US20100300120A1

US20100300120A1 - Refrigerator unit and/or freezer unit

Info

Publication number: US20100300120A1
Application number: US12/787,756
Authority: US
Inventors: Herbert Gerner
Original assignee: Liebherr Hausgeraete Ochsenhausen GmbH
Current assignee: Liebherr Hausgeraete Ochsenhausen GmbH
Priority date: 2009-05-28
Filing date: 2010-05-26
Publication date: 2010-12-02
Also published as: BRPI1001983A2; EP2282150A3; EP2282150A2; DE102010018459A1

Abstract

The present invention relates to a refrigerator unit and/or freezer unit having a first electronic controller which controls a second electronic controller. In accordance with the invention, the first electronic controller transmits control signals to the second electronic controller by the selective switching of one or more mains half cycles of a mains voltage. The present invention furthermore comprises a corresponding method for the operation of a refrigerator unit and/or freezer unit.

Description

The present invention relates to a refrigerator unit and/or freezer unit having a first electronic controller which controls a second electronic controller.
The first electronic controller can in this respect be the unit controller of the refrigerator unit and/or freezer unit; the second electronic controller can be the compressor controller of a speed-regulated compressor.
With compressors which are not speed regulated, the control usually takes place via the unit controller which switches the mains power for the compressor on or off via a thermostat switch in order thus to regulate the temperature in the refrigerator and/or freezer unit. In order also to be able to operate speed-regulated compressors at units having such a simple thermostat controller, the compressor speed can in this respect be controlled autonomously by the compressor controller in a drop-in version. For this purpose, corresponding algorithms are implemented in the compressor controller, e.g. for the time controlled increase or reduction of the speed or for the compressor load-dependent change of the speed. The control of the compressor controller of the speed-regulated compressor in this case takes place like the control of a standard compressor without speed regulation by switching on and off of a mains power signal which now serves as a control signal.
So that the unit controller can directly control the speed of the compressor, the use of separate control lines is known via which control signals for the compressor controller can be transmitted. In this respect, different protocols can be used. On the one hand, the compressor controller can communicate with the unit controller via a serial interface so that a bidirectional connection is also possible. Alternatively to this, speeds are associated with specific frequencies or frequency ranges generated by the unit controller so that only one frequency signal has to be transmitted via the signal line.
Both control variants have the disadvantage that additional costs arise due to the required control line and its laying. Different components are furthermore required for the control of a standard compressor or of a drop-in version and for the generation of a control signal for speed-regulated compressors, said components either resulting in an additional equipping of the control electronics or in equipping variants of the control electronics in dependence on whether a standard compressor or a drop-in version or a speed control of the compressor should be used.
It is therefore the object of the present invention to provide a refrigerator unit and/or freezer unit which allows a simpler and less expensive control of the second electronic controller via the first electronic controller.
This object is achieved by a refrigerator unit and/or freezer unit in accordance with claim 1 and by a method for the operation of a refrigerator unit and/or freezer unit in accordance with claim 14.
Advantageous aspects of the invention form the subject of the dependent claims.
The refrigerator unit and/or freezer unit in accordance with the invention has a first electronic controller and a second electronic controller, with the second electronic controller being controlled via the first electronic controller. In this respect, the first electronic controller transmits encoded control signals to the second electronic controller by the direct switching of one or more mains half cycles of a mains voltage. The second electronic controller decodes these control signals and can then use them e.g. for the control of a consumer of for internal control work.
This has the advantage that the otherwise required additional signal line for the transmission of control signals from the first electronic controller to the second electronic controller can be omitted so that the additional costs associated therewith are likewise omitted. In addition, different electronic controller systems no longer have to be provided for units in which a control only takes place by switching the mains voltage on and off and for such unit in which encoded control signals are transmitted by the direct switching of mains half cycles. The control can rather in each case take place via the same electronic controller system.
This is possible since it is possible to make use of components already usually present in controllers for the simple switching on and off of the mains voltage for the direct switching of one or more mains half cycles. The first controller in this respect advantageously includes a zero-crossing recognition of the mains voltage and switch elements for the switching of the mains voltage such as triacs.
In this respect, control signals can be superimposed on the mains voltage signal by the direct suppression of one or more mains half cycles of the mains voltage, said control signals then being able to be interpreted by the second electronic controller. This allows a particularly simple realization of a unidirectional communication from the first electronic controller to the second electronic controller. The number of the mutually following mains half cycles which are switched as a minimum for the generation of a signal in this respect determines the transmission speed. It must be taken into account in this respect that such an implemented protocol is bound to the mains frequency so that anyway only low transmission speeds can be realized.
The control signals are therefore advantageously encoded by the direct switching of individual mains half cycles or individual mains periods of the mains voltage. Individual mains half cycles or individual mains periods thus form the minimal signal resolution by which control signals can be encoded and transmitted.
In accordance with the invention, the first electronic controller is advantageously the unit controller of the refrigerator unit and/or freezer unit. It can control a further electronic controller in the refrigerator unit and/or freezer unit by switching the mains voltage half cycles.
Further advantageously, the second electronic controller is the compressor controller of a speed-regulated compressor. The compressor controller can thus be controlled in accordance with the invention by switching the mains voltage half cycles. In this respect, an electronic inverter system is usually used as a compressor controller.
The refrigerator unit and/or freezer unit in accordance with the invention has a mains voltage line via which the second electronic controller can be supplied with mains voltage. In a first embodiment, the control signals are, however, transmitted via an additional signal line to which the mains voltage signal is applied. In a second embodiment, the control signals are, in contrast, transmitted via the mains voltage line. It is hereby possible to completely dispense with additional signal lines since the signals are superimposed on the mains voltage supply.
On the use in accordance with the invention of a transmission of encoded control signals by switching a mains voltage signal, the power supply of the second electronic controller system or of the consumer controlled by this electronic controller system therefore takes place separately in the first embodiment. In the second embodiment, the mains voltage supply takes place, in contrast, by the mains voltage signal on which the control signals are superimposed. In this case, the signal line would simultaneously form a mains control line for the supply of the second control electronics.
The second embodiment of a refrigerator unit and/or freezer unit is in this respect a subject of the invention also independent of the signal generation by switching of one or more mains half cycles. It therefore includes a refrigerator unit and/or freezer unit having a first electronic controller and a second electronic controller, wherein the second electronic controller is supplied with mains voltage via a mains voltage line, wherein the first electronic controller transmits encoded control signals to the second electronic controller via the mains voltage line which are decoded by the second electronic controller. The encoding of the control signals advantageously takes place as was represented above.
The first controller is advantageously suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.
This has the advantage that the same electronics can be used for the control of the compressor both on the use of a standard compressor, of a drop-in version and of a speed-regulated compressor. The standard compressor is in this respect switched on and off directly by switching the mains voltage on and off, wherein this switching on and off of the mains voltage serves as a switch signal for the autonomous speed regulation in the drop-in version. In accordance with the invention, the compressor controller of a speed-regulated compressor can obtain encoded signals from the unit controller via the same electronics by the switching of mains half cycles of the mains voltage.
The communication between the first electronic controller and the second electronic controller advantageously takes place with reference to a protocol which is implemented in both electronic controllers. This is advantageously a digital protocol in this respect with which control commands are encoded by digital control signals.
It is furthermore advantageously a unidirectional protocol since this can be implemented with less effort.
The protocol is advantageously implemented in that a specific number of mains half cycles are combined to a telegram which digitally encodes the control signals. Ten half cycles or ten periods can e.g. be fixed as the telegram length.
The absence of a half cycle or of a period can then e.g. be interpreted as a 0; the presence of the half cycle or period as a 1. Corresponding encodings are then assigned to the respective control signals.
In an advantageous embodiment of the invention, in this request a sequence of a plurality of physical half cycles or periods are linked to form a logic unit to enable an error check. The absence e.g. of a half cycle or of a period followed by the presence of the half cycle or period can thus be interpreted as a logical 1; the presence of a half cycle or of a period followed by the absence of the half cycle or period as a logical 0.
In accordance with the invention, control signals for a switch-on command and/or a switch-off command are advantageously transmitted. A mains voltage signal can hereby be continuously applied, while the switch-on command and/or the switch-off command are transmitted by an encoded signal superimposed on the mains voltage signal for the switching on or off of a consumer or of the electronic controller itself. Such a protocol is advantageously implemented when the control signals are transmitted via a separate signal line.
It is alternatively possible that the switching on and off of the consumer controlled by the second controller is continued to be controlled by the switching on and off of the mains voltage, but that control signals are additionally transmitted with a switched-on mains voltage. No change in the control mode is thus required in the control of a standard compressor and of a speed-regulated compressor. Such a protocol is advantageously implemented when the control signals are transmitted via the mains voltage supply of the second controller.
In accordance with the invention, control signals for the desired speed of a speed-regulated compressor are advantageously transmitted. A control of the desired speed of the compressor is hereby possible via the unit controller without an additional signal line having to be provided.
The single control signal in this respect forms the desired speed in an embodiment of the invention. In this case, the switching on and off of the consumer controlled by the second controller is advantageously still controlled by the switching on and off of the mains voltage; in contrast, the protocol transmits the desired speed. Such a protocol is advantageously implemented when the control signals are transmitted via the mains voltage supply of the second controller.
Further advantageously, the second electronic controller can be set into a default state by a control signal. The ex works settings can hereby be restored.
Further advantageously, a display of an error memory can be started.
Further advantageously a diagnosis routine can be started to be able to diagnose errors.
Further advantageously, the second electronic controller can be set into different modes by the control signals. One or more of the following modes can in particular be provided: a default mode, a diagnosis mode, an error storage mode, a drop-in mode in which the speed of the compressor is controlled autonomously by the compressor controller, a speed pattern as well as different automatic modes with which the second controller reacts to the absence of control signals.
Further advantageously, the then current control commands for the second controller are transmitted at regular intervals. The security of the unidirectional protocol can hereby be improved.
Provision is advantageously made that the second electronic controller changes into an automatic mode on the absence of control signals. Provision can in particular be made in this respect that the consumer, in particular the speed-regulated regulated compressor, is regulated to a maximum speed or is completely switched off in the automatic mode. Provision can alternatively be made that the compressor is operated as in the drop-in mode in the automatic mode and the compressor controller of the compressor is controlled autonomously. The control of the speed can in this respect in particular take place in dependence on time or in dependence on the load.
A timer is advantageously provided in this respect which is reset again in each case on the input of a correct control signal, but which continues to run on the input of an erroneous control signal or on the absence of a control signal. If the timer in this respect exceeds a specific time duration of e.g. some minutes, the second controller changes into the automatic mode.
Further advantageously, in accordance with the invention, the control signals include information on the error recognition. This is in particular of advantage when it is a case of a unidirectional controller. The individual control command telegrams can hereby be secured to avoid erroneous transmissions. This can be realized e.g. by check sums or by a corresponding number of telegram repetitions.
The present invention furthermore includes a method for the operation of a refrigerator unit and/or freezer unit having a first electronic controller and a second electronic controller, said method including the following steps: Generation of encoded control signals in the first electronic controller by the direct switching of one or more mains half cycles of a mains voltage and decoding the control signals in the second electronic controller. The second electronic controller can then use the decoded control signals for the controlling of a consumer, in particular for the controlling of a compressor.
In a further embodiment, the present invention furthermore includes a method for the operation of a refrigerator unit and/or freezer unit having a first electronic controller and a second electronic controller, said method including the following steps: supplying the second electronic controller via a mains voltage line with a mains voltage, transmission of encoded control signals from the first electronic controller to the second electronic controller via the mains line, and decoding the control signals in the second electronic controller.
The method in accordance with the invention is in this respect advantageously used for the operation of a refrigerator unit and/or freezer unit, as was described above. The method in accordance with the invention in particular thus advantageously includes those features which were already described above with respect to the refrigerator unit and/or freezer unit.

The present invention will now be represented in more detail with reference to embodiments and to drawings. There are shown:

FIG. 1: an example protocol for the generation of encoded control signals in which the control signals are encoded by the switching of mains half cycles;

FIG. 2: an example protocol for the generation of control signals in which the control signals are encoded by the switching of mains half cycles;

FIG. 3: the state regulation of the second unit controller in accordance with a first embodiment (standard option);

FIG. 4: the operating state of the compressor in accordance with the first embodiment (standard option);

FIG. 5: a diagram on the sampling of the mains period;

FIG. 6: an embodiment of a signal encoding;

FIG. 7: a diagram on the synchronization of the signals;

FIG. 8: a control telegram in accordance with the first embodiment (standard option);

FIG. 9: a signal telegram in accordance with the first embodiment (standard option);

FIG. 10: a diagram of the error handling in accordance with the first embodiment (standard option);

FIG. 11: the state regulation of the second unit controller in accordance with a second embodiment (AC option);

FIG. 12: a control telegram in accordance with the second embodiment (AC option); and

FIG. 13 the error handling in accordance with the second embodiment (AC option).

The embodiments of the present invention show transmission controls between the unit controller of a refrigerator unit and/or freezer unit and the compressor controller of a speed-regulated compressor by which the unit controller can transmit encoded control signals to the compressor controller. These encoded control signals are decoded by the compressor controller and used for the control of the compressor. The transmission protocol is in this respect based on the switching of individual mains half cycles or mains periods. The control signals are therefore encoded in that individual mains half cycles or mains periods of the mains voltage are selectively suppressed and hereby form a signal which can be interpreted by the compressor controller. The additional frequency signal line previously required for the control can hereby be omitted. Furthermore, a variant reduction can be achieved in the compressor controller since the protocol can be realized in a manner open for future speed versions.
The representation in this respect takes place with reference to the control of a compressor in the following. The data transfer used between a first controller and a second controller can, however, also be used in the same manner for the control of any desired other unit components.
The refrigerator unit and/or freezer unit in accordance with the invention in this respect has a unit controller which controls the functions of the unit and in particular serves the maintenance of a temperature in the interior of the refrigerator. At least one temperature sensor is provided for this purpose which is connected to the unit controller. The unit controller determines control signals for the control of the compressor controller from the data of the temperature sensor. The compressor controller in this respect serves for the control of the speed of the speed-regulated compressor and is usually made as a frequency inverter.
The compressor controller in this respect is connected in accordance with the invention via a signal line to the unit controller which serves the switching on and off of the compressor in standard units. Control signals encoded in accordance with the invention are now transmitted via this signal line by switching from one or more mains half cycles of the mains voltage signal to the compressor controller. In the embodiment, a protocol is generated by selective switching of individual mains voltage half-cycles or mains-voltage periods which can be interpreted by the compressor controller. This enables the realization of a unidirectional protocol from the unit controller to the speed-regulated compressor.
The signal line can in this respect be the mains voltage line by which the compressor controller is supplied with mains voltage or it can be an additional signal line.
In this respect, triacs can be used for the implementation of the protocol on the unit controller side, said triacs also being used for the control of standard compressors, and the zero crossing recognition of the mains voltage usually already present can be used. The inventive control of speed-regulated compressors via a mains voltage signal thus also allows standard compressors to be controlled by the same electronic unit system, said standard compressors being switched on and off by simple switching on and off of the mains voltage.
The use of drop-in versions is naturally also possible in which the otherwise autonomous speed regulation receives a switching signal for the switching on or off of the compressor by the unit controller by the switching on and off of the mains voltage. On the use of a drop-in version or of a speed controller in accordance with the invention, the power supply of the compressor controller or of the compressor can take place separately in this respect. Alternatively, however, the drop-in version can also be only be supplied with mains voltage when the compressor should be operated so that the control signals of the mains voltage are superimposed on the mains voltage supply, with in particular only the desired speed being transmitted.
The protocol in accordance with the invention for the control of the compressor controller can in this respect contain one or more of the following control signals:

- Signals for the desired speed
- Signal for compressor On
- Signal for compressor Off
- Signals for setting different modes of compressor control.

In this respect, in particular one or more of the following modes can be implemented as different modes for the compressor control:

- Default mode
- Diagnosis mode
- Error saving mode
- Drop-in mode in which the speed of the compressor is controlled autonomously by the compressor controller, e.g. by time-controlled increase or reduction of the speed or by a compressor load-dependent change of the speed
- No signal condition: Continuously off: Here, on the absence of control signals, the compressor controller reacts in that the compressor is switched off as long as no new control signals are present
- No signal condition: Continuously on: Here, on the absence of control signals, the compressor controller reacts in that the compressor is operated autonomously for so long until control signals are present again Speed pattern mode.

Since the protocol shown in the embodiment only allows a unidirectional communication, a corresponding error handling has to be implemented.
On the one hand, it has to be defined how the compressor controller reacts on the absence of control signals. Provision can in particular be made in this respect that control signals with the then current desired operating states are transmitted regularly, e.g. at intervals of some seconds. In this respect, a timer is provided in the compressor controller which measures the time which has passed since the reception of the last error-free control signal. If this time exceeds a specific limit of e.g. some minutes, the compressor controller switches into an automatic mode.
The individual signal telegrams can furthermore be secured to avoid erroneous transmissions. This can be realized both by check sums and by a corresponding number of telegram repetitions.
In addition, a plurality of physical signal lines can be combined to form a logical signal unit to improve the transmission reliability.
Since the protocol is bound to the mains frequency, only a low transmission speed can be realized. In this respect, as shown in FIG. 1, a half cycle of the mains voltage can be used as the minimal signal resolution. Alternatively, as shown in FIG. 2, a period of the mains voltage can be used as the minimal signal resolution. Three or more mains half cycles can naturally also be used as the minimal signal resolution; however this reduces the transmission speed. A protocol can now be implemented e.g. in that a specific number of signals are combined to form a telegram which digitally encodes the control signals. E.g. ten half cycles or ten periods can be fixed as the telegram length.
The absence of a half cycle or of a period is then interpreted as a 0. The presence of the half cycle or period as a 1. A plurality of physical units can be combined to form a logical unit for better error handling. Corresponding encodings are then assigned to the respective control signals. The encoding and decoding of the control signals in this respect advantageously takes place by a microcontroller or a microprocessor.
The present invention thus allows a simple and inexpensive control of the compressor controller in that the selective switching of one or more mains half cycles of a mains voltage signal is/are used for the transmission of encoded signals. This enables both a reduction in the variants of the unit controller and in the variants for the compressor controller.
The protocol shown in the embodiment, which is implemented by switching individual mains half cycles or mains periods, in this respect enables a particularly simple unidirectional communication between the unit controller and the compressor controller. The present invention can in this respect also be used for the communication between other electronic components of a refrigerator unit and/or freezer unit. The unit controller can in this respect in particular also control other components in the refrigerator unit and/or freezer unit in accordance with the invention.
In the following, the present invention will now be represented in more detail again with reference to two specific examples.
Functional Description of the AC Protocol
As a rule, triacs are used for the control of standard compressors. The unit controller furthermore as a rule includes a zero crossing recognition of the mains voltage. In accordance with the invention, in this respect, a protocol is generated by selective switching of individual mains voltage half cycles which can be interpreted by the compressor controller. The realization of a unidirectional protocol from the unit controller to the speed-regulated compressor is possible by this method of signal transmission.
Since the protocol in this form is only possible unidirectionally, a corresponding error handling has to be implemented which

- defines corresponding reactions of the compressor controller on the absence of control signals
- secures the individual telegrams to avoid error transmissions

Since the protocol is bound to the mains frequency, only a low transmission speed can be realized. Two example protocols with mains half cycles and with mains periods are shown in FIGS. 1 and 2. Two variants are explained in the following for the realization of the control of a compressor.
Standard Option:
In this variant, a cable having an additional conductor core (L, N, PE+“signal line”) is required for the connection of the compressor. The voltage supply of the compressor electronics is realized as previously, i.e. the mains voltage is applied to the compressor electronics the whole time. The cable for the transmission of the frequency signal is dispensed with. Instead, a mains voltage signal which is modulated by the triac output and which includes the control signals for the compressor is transmitted to the compressor electronics. This line is connected to the drop-in input of the compressor electronics.
AC Option:
In this variant, the previously used supply line (L, N, PE) is required. This line serves both the voltage supply of the compressor and the transmission of the protocol. It is the aim to modulate commands onto the mains voltage by skipping individual mains voltage half cycles. These commands are interpreted by the compressor controller and the compressor is controlled accordingly. Unlike in the standard option, in this method, the compressor electronics is not supplied with the mains voltage for the whole time. The compressor is only supplied with voltage during a compressor demand.
This method of compressor control provides the following advantages:

- Standardization of the control of standard compressors and VCC compressors
- Standardization of the electronics of standard compressors and VCC compressors when the standard compressors are not influenced by the protocol
- Energy saving by switching off the supply voltage of VCC compressors when they are not being controlled

Description of the Standard Option
The following control commands and states are converted for the standard option:
Commands:

- cmd.Drop-in On
- cmd.Speed specification On
- cmd.Set speed
- cmd.No signal condition On
- cmd.No signal condition Off
- cmd.Default state setting
- cmd.Reset to default
- cmd.Compressor On
- cmd.Compressor Off

States:

- state.Protocol mode
- state.Drop-in mode

The state regulation in accordance with the Standard option is shown in FIG. 3; the operating state of the compressor in FIG. 4.
Commands
cmd.Drop-in On
See state diagram “State regulation, Standard option”
The status state.Drop-in mode becomes active with the transmission of the command cmd.Drop-in On
cmd.Speed specification On
See state diagram “State regulation, Standard option”
The status state.Protocol mode becomes active with the transmission of the command cmd.Speed specification On
cmd.Set speed
See state diagram “State regulation, Standard option”
The status state.Protocol mode becomes active with the transmission of the command cmd.Set speed
This command additionally includes the speed specification of the compressor
cmd.No signal condition On
The command cmd.No signal condition On serves the setting of the compressor speed in emergency operation as well as the setting of the compressor speed in the default state.
If the command cmd.No signal condition On is transmitted, the compressor runs in emergency operation and at a default setting at 3000 1/min.
cmd.No signal condition Off
The command cmd.No signal condition Off serves the setting of the compressor speed in emergency operation as well as the setting of the compressor speed in the default state.
If the command cmd.No signal condition Off is transmitted, the compressor is switched off and does not run in emergency operation and in the default setting.
cmd.Default state setting
The command cmd.Default state setting serves the selection of the compressor status during the default state.
Default state=>Protocol mode: signal-telegram, command bit D0=0
Default state=>Drop-in mode: signal-telegram, command bit D0=1
The drop-in mode is selected in the default state as standard.
cmd.Reset to default
See state diagram “State regulation, Standard option”
The command cmd.Reset to default initializes the compressor with its default values.
Default mode: dependent on the set default mode (drop-in mode or protocol mode)

- The drop-in mode is selected as standard

No signal condition: depending on the cmd.No signal condition

- No signal condition=On is standard

Speed dependent on the status No signal condition

- With No signal condition=Off→0 1/min
- With No signal condition=On→3000 1/min

cmd.Compressor On
See figure “Operating state compressor standard option”
The command cmd.Compressor On switches the compressor on. The signal is sent repeatedly to the compressor electronics by the unit controller every 15 seconds. This serves the updating of the operating state of the compressor electronics and is functionally comparable with the previously permanently applied frequency signal.
cmd.Compressor Off
See figure “Operating state compressor standard option”
The command cmd.Compressor Off switches the compressor off in the protocol mode.
The drop-in mode is switched off by the absence of the voltage signal.
Status Description
state.Protocol mode
The protocol mode represents the then current VCC regulation operation. This state becomes active as soon as a valid protocol is applied. Exception cmd.Drop-in On
The compressor is updated to its new then currently valid compressor speed by the transmission of the command cmd.Set speed. After the transmission of cmd.Compressor On, the compressor starts with the now valid compressor speed. The signal cmd.Compressor On must e.g. be repeated as a “refresh” every 15 seconds, for example. The signal cmd.Set speed should e.g. be repeated every 5 minutes.
The compressor runs with the speed set in the default setting with the transmission of the command cmd.Speed specification On and subsequent cmd.Compressor On (without speed specification). This is updated at the latest after e.g. 5 minutes by the signal cmd.Set speed.
If the command cmd.Reset to default is transmitted to the compressor electronics, the compressor starts with the set default speed after the signal cmd.Compressor On was transmitted.
The compressor is switched off by transmitting the command cmd.Compressor Off. The compressor electronics is, however, still in the status state.Protocol mode and is waiting for the next command.
state.Drop-in mode
This mode represents the then current drop-in operation.
This state becomes active by the commands cmd.Drop-In-On or cmd.Reset to default (default mode=drop-in mode).
The compressor starts its drop-in routine with the transmission of the command cmd.Drop-in On or cmd.Reset to default and subsequent transmission of cmd.Compressor On. This drop-in routine automatically calculates the required speed and controls the compressor in accordance with the implemented algorithm.
If no voltage is applied to the drop-in input, the compressor switches off. The compressor electronics is still in the status state.Drop-in mode and is waiting for the voltage signal at the drop-in input or for the next valid command.
The state.Drop-in mode is active as standard after a power-up.
Error/Diagnosis Display
The error/diagnosis display serves the error monitoring of the protocol transmission. If an error occurs during the transmission of the telegram, an error counter is incremented and an LED lights up for 400 ms.

- Visualization of an erroneous protocol transmission
- Counting the transmission errors which occurred (a possibility of reading out the error counter is to be provided)

Signal Resolution
The signal resolution amounts to a mains period such as is shown in FIG. 2.
Zero Crossing Recognition
The zero crossing recognition of the mains voltage plays a decisive role in the functionality of the protocol transmission. If the zero crossings or the zero crossing recognition of the unit electronics and of the compressor electronics are not synchronized to one another, an error-free telegram transmission is not possible. The mains voltage has a different stability, depending on the country. Interference spikes, ripple control signals and, in part, a plurality of closely adjacent zero crossings can occur. These interference types must be recognized and interpreted in the same way both by the unit electronics and by the compressor electronics. It is thus ensured that the same zero crossings are recognized. A synchronization of unit electronics and compressor electronics and an error-free transmission of the protocol is thus possible.
Sampling the Mains Half Cycle
The signal must be sampled a number of times during a mains period for an error-free detection of the mains periods. It is basically enough to sample the positive mains voltage half cycle. If the corresponding mains voltage half cycle is present. this corresponds to a high level; if the mains voltage half cycle is cut-off, this corresponds to a low level. A digitizing of the mains voltage is achieved by the recognition and interpretation of the mains periods.
FIG. 5 shows such a sampling of the mains period.
Speed Resolution
A speed setting in the range from 0 to 8191 1/min (13 bit encoding) is theoretically possible.
A seed setting with the precision factor 10 is required.
If a speed demand is made which exceeds the maximum speed of the compressor, the compressor runs with its highest possible speed.
If a speed demand is made which is below the speed of the compressor possible at a minimum, the compressor runs with its smallest possible speed.
The minimum or maximum possible speed can be seen from the respective data sheet of the compressor.
Telegram Structure
Signal Encoding
Standard Option:
With the standard option, a digitizing of the mains voltage is achieved by switching or omitting whole, or selectively half, mains voltage periods.
AC option:
With the AC option, a digitizing of the mains voltage is achieved by switching or omitting mains voltage half cycles. The positive half cycle of the sinusoidal signal is in each case switched or omitted for the encoding of the mains voltage signal.
Two bits are required in the telegram for the transmission and for the representation of one “logical bit” (if necessary, a third bit could be donated).
Bit status “1”=>0 1
Bit status “0”=>1 0
An example for the signal encoding is shown in FIG. 6.
This method of bit transmission allows an error recognition of the protocol, still during the transmission, by the compressor electronics. A protocol repetition is not necessary.
The parity of the protocol is constant.
An error case occurs when:

- 3×“0” is transmitted.
- 3×“1” is transmitted.

Synchronization of Unit Electronics and Compressor Electronics
To ensure an error-free transmission of the protocol, the unit electronics and the compressor electronics have to be synchronized to one another. This is achieved via the zero crossings of the mains voltage signal.
The synchronization is carried out before every protocol transmission and is realized via the pattern “11111”. This pattern does not occur during the protocol transmission and thus allows a delineation toward the telegram. The start bit of the protocol is recognized and the interpretation of the data is started by the state change 1→0.
At least 5 bits with the state “1” must be transmitted for the synchronization. With the AC option, a “1” must be transmitted for so long until the compressor has started up.
An example for the synchronization is shown in FIG. 7.
Command Addressing
The control telegram or the signal telegram is used for data transmission depending on the command. The commands are addressed differently.


Command	Address	Protocol

cmd.Set speed	0x0	Control
		telegram
cmd.Drop-in On	0xE	Signal
		telegram
cmd.Speed specification On	0x2	Signal
		telegram
cmd.No signal condition On	0xC	Signal
		telegram
cmd.No signal condition Off	0x5	Signal
		telegram
cmd.Reset to default	0x9	Signal
		telegram
cmd.Compressor On	0x8	Signal
		telegram
cmd.Compressor Off	0xB	Signal
		telegram
cmd.Default state setting	0xF	Signal
		telegram

The 4-bit addressing allows commands which may additionally be required.
Protocol Structure, Standard Option
A transmission counts as a protocol when the start bit and the address are correctly interpreted. If an error occurs during this transmission, it is not declared as an erroneous protocol. This method is introduced since otherwise a protocol error would be recognized on each absence of a mains half cycle.
Control Telegram
The following Figure shows the structure of a control telegram. This protocols serves the transmission of the command cmd.Set speed with the compressor speed.
The control telegram is shown in FIG. 8.
Telegram Structure:
S =Start bit=1
A0 . . . A3=Decoding command
D0 . . . D12=Speed specification
EB=End bit=0
Signal Telegram
The following Figure shows the structure of a signal telegram. This protocol serves the transmission of the commands. (See command addressing)
The signal telegram is shown in FIG. 1.
Telegram Structure:
ST=Start bit=1
A0 . . . A3=Decoding command
D0=State variable→low active
EB=End bit=0
Error Treatment
Error Recognition
The system of bit transmission listed under signal encoding was developed to recognize errors during the transmission of the protocols. This system makes it possible to transmit telegrams only once and to check them already during the transmission. Telegram repeats or a monitoring by suitable error recognition methods such as CRC are not required.
Standardized protocols are used for the transmission of the data; if an error occurs, a corresponding error handling is carried out.
The following protocol structure must be observed for the transmission of the data. An error in this structure results in a defined error handling.

- Start bit: First pulse of the telegram must correspond to “logical 1”
- Period length: The time of one period length is present between two pulses within a telegram
- Addressing: The commands must have a defined address
- End bit: The last pulse of a valid code word must correspond to a “logical 0”
- Call length: No further bit with information may be transmitted for e.g. 4 seconds after the end bit.
- Refresh: A refresh must be transmitted by cmd.Compressor On in dependence on the selected state.

Error Treatment:
The following Figure shows the error handling of the standard protocol.
If a valid command is applied, the timer is reset and the then current demand is carried out. The timer is started.
While the timer is e.g. less than 2.5 minutes, the compressor electronics waits for a new valid command, but simultaneously carries out the then currently valid demand. If an invalid protocol is transmitted, this is displayed via the error/diagnosis display; the timer is incremented further. If a valid command is transmitted, the timer is reset, the then current demand is processed and the timer is started again.
If the timer is larger than 2.5 minutes, the compressor runs at the speed set in the No signal condition and waits for a new valid command of the unit electronics. If an invalid protocol is transmitted, this is displayed via the error/diagnosis display. If a valid command is transmitted, the timer is reset, the then current demand is processed and the timer is started again
In FIG. 2, a flowchart of the error handling is shown.
AC Option
Functional Description AC Option
The transmission of the protocol takes place in parallel to the voltage supply via the supply line of the compressor electronics. No additional line or conductor core is required.
The control signals are modulated onto the supply voltage of the compressor by switching or omitting individual mains voltage half cycles. They are then interpreted and processed by the compressor electronics. The compressor is controlled in accordance with the transmitted command.
The voltage supply is only applied during a compressor demand at the compressor electronics. If no compressor demand is present, the compressor electronics is currentless and the compressor cannot be switched on.
This method of compressor control provides the following advantages:

- Standardization of the control of standard compressors and VCC compressors
- Standardization of the electronics of standard compressors and VCC compressors when the control of the standard compressors is not influenced by the protocol
- Energy saving by switching off the supply voltage of the compressor electronics if no compressor demand is applied

Protocol Structure
The following points are identical to the Standard option and are not explicitly listed here:

- Protocol demands
- Zero crossing recognition
- Sampling the mains half cycle
- Speed resolution
- Signal encoding
- Synchronization of unit electronics and compressor electronics

The following control commands and states are implemented for the AC option:
Commands:

- cmd.Set speed

States:

- state.Protocol mode
- state.Drop-in mode

The state regulation of the AC option is shown in FIG. 11.
Command
cmd.Set speed
See state diagram “State regulation, AC option”
The status state.Protocol mode becomes active with the transmission of the command cmd.Set speed
This command includes the speed specification of the compressor
Status Description
state.Protocol mode
The protocol mode represents the then current VCC regulation operation and becomes active with the command cmd.Set speed.
The compressor is updated to its new valid compressor speed by the transmission of the command cmd.Set speed and a timer is started.
The command cmd.Set speed must be repeated and transmitted to the compressor electronics e.g. every 5 minutes. In this respect, the speed of the compressor is updated and the timer is reset.
If a valid command and the mains voltage are present at the compressor electronics, the compressor runs at the then currently set speed in the protocol mode.
If an error occurs on the updating of the command or if the times is >=12 minutes, the compressor changes from the protocol mode into the drop-in mode and continues to run at the speed buffered in the drop-in mode.
The command “Compressor ON/OFF” is realized in the AC option via the switched/applied voltage supply of the compressor.
If no compressor demand is applied by the unit electronics, the voltage supply of the compressor is set and the compressor switches off.
state.Drop-in mode
This state represents the then current drop-in operation and becomes active from the protocol mode as standard after a power-up or after the expiry of the timer.
The drop-in mode calculates the required speed automatically and controls the compressor in accordance with the implemented algorithm.
If the protocol mode is active, the drop-in mode continues to run parallel thereto in the background without influencing it. If the command cmd.Set speed is absent or invalid, the drop-in mode becomes active and the compressor continues to run with the then currently valid drop-in speed.
If the compressor should be operated in drop-in mode, only the voltage supply of the compressor is required. A transmission of the command cmd.Set speed is not necessary.
If no compressor demand is present, the compressor is not supplied with power.
Error/Diagnosis Display
Control: see status diagram Error treatment, AC option
The status state.Error/Diagnosis serves the error monitoring of the protocol transmission. If an error occurs during the transmission of the telegram, an error counter is incremented and an LED lights up for 400 ms.

Power Up
The state.Drop-in mode is active as standard after a power-up.
A start delay (e.g. 5 seconds) must run before the compressor powers up. This start delay ensures that the transmitted protocol was completely transmitted and was interpreted by the compressor electronics.
If a valid protocol is applied before the start delay has expired, the compressor powers up before the expiry of the start delay.
The unit electronics and compressor electronics are synchronized to one another after a power up. The command cmd.Set speed is transmitted and decoded after the synchronization. If a valid command with a then current speed specification is applied, the compressor starts in the protocol mode at the then current speed.
The unit electronics and compressor electronics are synchronized to one another after a power up. The command cmd.Set speed is transmitted and decoded after the synchronization. If no valid command with a then currently valid speed specification is applied after the expiry of the start delay, the compressor starts in the drop-in mode with its implemented drop-in routine.
Telegram Structure
A transmission is deemed a protocol if e.g. the start bit and the first 4 bits of the speed setting were correctly interpreted. If an error occurs during this transmission, it is not declared as an erroneous protocol. This method is introduced since otherwise a protocol error would be recognized on each absence of a mains half cycle.
The following Figure shows the structure of the control telegram. This protocol serves the transmission of the command cmd.Set speed with the then valid compressor speed. No addressing is necessary.
FIG. 3 shows the control telegram of the AC option.
Telegram Structure:
ST=Start bit=1
D0 . . . D12=Speed specification
EB=End bit=0
Error Treatment
The following Figure shows the error handling of the AC option.
If a valid command is applied, the timer is reset and the then current demand is carried out. The timer is started.
While the timer is e.g. less than 12 minutes, the compressor electronics waits for a new valid command, but simultaneously carries out the then currently valid demand. If an invalid protocol is transmitted, this is displayed via the error/diagnosis display; the timer is incremented further. If a valid command is transmitted, the timer is reset, the then current demand is processed and the timer is started again.
If the timer is larger than 12 minutes, the compressor changes into the drop-in mode and waits for a new valid command of the unit electronics. If an invalid protocol is transmitted, this is displayed via the error/diagnosis display. If a valid command is transmitted, the timer is reset, the then current demand is processed and the timer is started again
FIG. 4 shows the error handling of the AC option.
Voltage Supply
The compressor is supplied with voltage via the AC line. Since the commands are modulated onto the voltage supply, the omission of individual mains voltage half cycles occurs in the supply of the compressor. This may not influence or damage the compressor. It must maintain its full functionality and may not switch off due to the omission of mains voltage half cycles.
Standard Compressor
The AC option also allows the control of standard compressors in addition to the control of VCC compressors. In comparison with VCC compressors, they do not need any control commands, but only the supply voltage for the operation. If an agreement is made that the same control is realized both for standard compressors and for VCC compressors, it is possible to save some hardware and software variants of the unit electronics. It is, however, a requirement that both standard compressors and VCC compressors can compensate the omission of the mains voltage half cycles and can continue to run without errors.

Claims

1-10. (canceled)

11. A refrigerator unit and/or freezer unit having a first electronic controller which controls a second electronic controller, wherein the first electronic controller transmits control signals to the second electronic controller by the selective switching of one or more mains half cycles of a mains voltage.

12. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the control signals are encoded by the selective switching of individual mains half cycles or of individual mains periods of the mains voltage.

13. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the first electronic controller is the unit controller of the refrigerator unit and/or freezer unit; and/or the second electronic controller is the compressor controller of a speed-regulated compressor.

14. A refrigerator unit and/or freezer unit in accordance with claim 11, comprising a mains voltage line via which the second electronic controller is supplied with mains voltage, wherein the control signals are transmitted via the mains voltage line or via an additional signal line.

15. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

16. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the communication between the first electronic controller and the second electronic controller takes place with reference to a protocol which is implemented in both electronic controllers.

17. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein control signals for a switch-on command and/or a switch-off command are transmitted; and/or control signals for the desired speed of a speed-regulated compressor are transmitted; and/or the second electronic controller can be set into a default state by a control signal; and/or a display of an error store and/or a diagnosis routine can be started; and/or the second electronic controller can be set into different modes by the control signals.

18. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the second electronic controller changes into an automatic mode on the absence of control signals.

19. A refrigerator unit and/or freezer unit in accordance with claim 11, wherein the control signals include information on the error recognition.

20. A method for the operation of a refrigerator unit and/or freezer unit having a first electronic controller which controls a second electronic controller, in particular for the operation of a refrigerator unit and/or freezer unit in accordance with claim 11, comprising the steps of

generating encoded control signals in the first electronic controller by the selective switching of one or more mains half cycles of a mains voltage; and

decoding the control signals in the second electronic controller.

21. A refrigerator unit and/or freezer unit in accordance with claim 12, wherein the first electronic controller is the unit controller of the refrigerator unit and/or freezer unit; and/or the second electronic controller is the compressor controller of a speed-regulated compressor.

22. A refrigerator unit and/or freezer unit in accordance with claim 21, comprising a mains voltage line via which the second electronic controller is supplied with mains voltage, wherein the control signals are transmitted via the mains voltage line or via an additional signal line.

23. A refrigerator unit and/or freezer unit in accordance with claim 13, comprising a mains voltage line via which the second electronic controller is supplied with mains voltage, wherein the control signals are transmitted via the mains voltage line or via an additional signal line.

24. A refrigerator unit and/or freezer unit in accordance with claim 12, comprising a mains voltage line via which the second electronic controller is supplied with mains voltage, wherein the control signals are transmitted via the mains voltage line or via an additional signal line.

25. A refrigerator unit and/or freezer unit in accordance with claim 24, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

26. A refrigerator unit and/or freezer unit in accordance with claim 23, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

27. A refrigerator unit and/or freezer unit in accordance with claim 22, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

28. A refrigerator unit and/or freezer unit in accordance with claim 21, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

29. A refrigerator unit and/or freezer unit in accordance with claim 14, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.

30. A refrigerator unit and/or freezer unit in accordance with claim 13, wherein the first controller is suitable, alternatively to the control of the second electronic controller, to control a consumer directly by switching the mains voltage on and off.