Refrigerant Circuit and Refrigerant Compressor

Abstract

In order to provide a control unit which can cooperate with a great variety of operating units and/or status acquisition units, it is proposed that the control unit comprises a base module which has at least one processor and at least one memory store for the required program code for operating the processor and terminals for operating units carrying out basic functions and/or status acquisition units and that the processor and the program code stored in the memory store are configured such that therewith additional functions of an additional module connectable to the base module are also executable.

Claims

1. A refrigerant compressor, having a compressor unit which draws in refrigerant with a suction port, compresses it and delivers it by way of a pressure port, wherein the refrigerant compressor has an electrical drive unit driving the compressor unit and wherein the refrigerant compressor is provided with a control unit which cooperates with at least one of i) operating units and ii) status acquisition units associated with the refrigerant compressor or the refrigerant circuit, wherein the control unit comprises a base module which has at least one processor and at least one memory store for the required program code and data for operating the processor and also terminals for operating units carrying out at least one of i) basic functions and ii) status acquisition units and wherein the processor and the program code stored in the memory store are configured so that operating units carrying out additional functions by way of an additional module connectable to at least one of i) the base module and ii) status acquisition units are also operable with these.

2. The refrigerant compressor according to claim 1, wherein, for the execution of additional functions, the base module is connectable to an additional module which has terminals for operating units carrying out at least one of i) the additional functions and ii) the status acquisition units, and wherein the additional module enables, by way of mediatory communication between the base module and at least one of i) the operating units and ii) the status acquisition units connected to the additional module, the execution of the additional functions by way of the operation of at least one of i) the operating units and ii) the status acquisition units by the base module.

3. The refrigerant compressor according to claim 1, wherein a communication between the base module and the additional module connected thereto takes place directly by way of electrical connecting elements between the base module and the additional module.

4. The refrigerant compressor according to claim 2, wherein the mediatory communication of the respective additional module comprises at least one of i) a signal conversion and ii) a signal processing and iii) an intelligent signal processing and iv) an evaluating signal processing.

5. The refrigerant compressor according to claim 1, wherein different additional modules are connectable to the base module, of which each enables an operation of different combinations of at least one of i) operating units and ii) status acquisition units by way of mediatory communication between the base module and these different combinations of at least one of i) operating units and ii) status acquisition units.

6. The refrigerant compressor according to claim 1, wherein the control unit has a controller housing arranged on the refrigerant compressor, which is configured to accommodate the base module and also to accommodate at least one additional module.

7. The refrigerant compressor according to claim 6, wherein, in addition to the base module, different additional modules are insertable into the controller housing.

8. The refrigerant compressor according to claim 6, wherein the controller housing has mounting receptacles for fixedly connecting the base module thereto.

9. The refrigerant compressor according to claim 6, wherein the controller housing has mounting receptacles for fixedly connecting the one additional module thereto.

10. The refrigerant compressor according to claim 8, wherein the mounting receptacles are arranged on a housing base of the controller housing, wherein in particular the mounting receptacles are connected by way of reinforcements to the housing base and wherein in particular the reinforcements dampen vibrations of the housing base.

11. The refrigerant compressor according to claim 10, wherein the housing base is provided with vibration damping structures.

12. The refrigerant compressor according to claim 10, wherein the respective mounting bases for the base module and the additional module are arranged on the reinforcements of the housing base.

13. The refrigerant compressor according to claim 10, wherein the respective mounting bases for the base module and the additional module are arranged on the same reinforcements connected to the housing base.

14. The refrigerant compressor according to claim 6, wherein the base module mounted in the controller housing and the additional module connected thereto are connected to one another by way of a plug-in connector.

15. The refrigerant compressor according to claim 14, wherein the plug-in connector is secured by fixing the base module by way of its mounting base and the fixing of the additional module is secured by way of its mounting base.

16. The refrigerant compressor according to claim 1, wherein the base module for at least one of i) the operating units and ii) the status acquisition units has at least one low voltage terminal, in particular for DC voltage, and at least one terminal, in particular for AC voltage.

17. The refrigerant compressor according to claim 1, wherein the additional module for the operation of at least one of i) the operating units and ii) the status acquisition units has at least one low voltage terminal, in particular for DC voltage, and at least one mains voltage terminal, in particular for AC voltage.

18. The refrigerant compressor according to claim 1, wherein the base module has at least one BUS terminal unit.

19. The refrigerant compressor according to claim 1, wherein the base module has a communication unit for wireless communication.

20. The refrigerant compressor according to claim 1, wherein the base module has a terminal for communication with a system controller of the refrigerant circuit.

21. The refrigerant compressor according to claim 20, wherein the terminal for communication with the system controller is configured as a BUS terminal unit or as a wireless communication unit.

22. The refrigerant compressor according to claim 1, wherein the additional module has a BUS terminal unit.

23. The refrigerant compressor according to claim 1, wherein the drive unit is operable by way of a frequency converter and wherein the frequency converter is controlled by the base module.

24. The refrigerant compressor according to claim 1, wherein the drive unit is operable by way of a frequency converter and wherein the frequency converter is controlled by the additional module by way of the base module.

25. The refrigerant compressor according to claim 1, wherein, on occurrence of damage-prone operating states, the base module detects them by way of the processor and stores an alarm signal and wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a display unit for the display of possible operating states, and wherein the base module controls, in particular, the display unit such that it displays at least one of i) an alarm signal recognized by the base module and ii) a stopping of the drive unit and iii) a start readiness of the control unit.

26. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module detects a temperature of the electrical drive unit by way of a temperature sensor.

27. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a lubricant sensor as a status acquisition unit and wherein the base module detects the values of the lubricant sensor.

28. The refrigerant compressor according to claim 27, wherein the base module evaluates the values of the lubricant sensor.

29. The refrigerant compressor according to claim 1, wherein the base module as the operating unit controls a lubricant feed from a lubricant separator to the compressor unit by way of a lubricant feed unit connected to at least one of i) the base module and ii) the additional module of the control unit.

30. The refrigerant compressor according to claim 29, wherein the lubricant feed unit is configured as a lubricant injection valve.

31. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a compressed gas temperature sensor as a status acquisition unit and wherein the base module detects the values of the compressed gas temperature sensor.

32. The refrigerant compressor according to claim 31, wherein the base module evaluates the values of the compressed gas temperature sensor, in particular while taking account of stored reference values.

33. The refrigerant compressor according to claim 1, wherein at least one of the base module and ii) the additional module of the control unit is connected to a high pressure sensor as a status acquisition unit and wherein the base module detects the values of the high pressure sensor.

34. The refrigerant compressor according to claim 33, wherein the base module passes on values that are at least one of i) detected and ii) determined, in particular by way of sensors.

35. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a lubricant heater as an operating unit and wherein, in particular, the base module switches the lubricant heater on or off.

36. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a power control unit of the compressor unit and wherein the base module controls the power control unit.

37. The refrigerant compressor according to claim 36, wherein the base module controls the power control unit according to a power demand of the system control unit.

38. The refrigerant compressor according to claim 36, wherein the base module controls the power control unit by way of the at least one processor dependent upon the compressed gas temperature detected by the compressed gas temperature sensor, while taking account of specifications stored in the memory store.

39. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a suction gas temperature sensor as a status acquisition unit and wherein the base module detects the values of the suction gas temperature sensor.

40. The refrigerant compressor according to claim 1, wherein the processor of the base module compares the values of the suction gas temperature sensor with reference values stored in the memory store or determined by the processor according to an operating state of the refrigerant compressor.

41. The refrigerant compressor according to claim 39, wherein if a reference value for the suction gas temperature is undershot, the base module communicates with the system controller.

42. The refrigerant compressor according to claim 36, wherein the base module controls the power control unit by way of the at least one processor, while taking account of the compressed gas temperature and the suction gas temperature and while taking account of specifications stored in the memory store.

43. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit are connected to a fan for cooling the compressor unit as an operating unit and wherein the base module controls the fan.

44. The refrigerant compressor according to claim 43, wherein the base module controls the fan by way of the at least one processor, while taking account of the compressed gas temperature and while taking account of specifications stored in the memory store.

45. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit are connected to an injection unit for refrigerant as an operating unit and wherein the base module controls the injection unit.

46. The refrigerant compressor according to claim 45, wherein, by way of the at least one processor, the base module controls the injection unit, while taking account of the compressed gas temperature and while taking account of specifications stored in the memory store or determined by the processor according to further status variables.

47. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to an ambient temperature sensor as a status acquisition unit and wherein the base module detects the values of the ambient temperature sensor.

48. The refrigerant compressor according to claim 46, wherein by way of the processor, the base module evaluates the values of the ambient temperature sensor according to reference values specified in the memory store.

49. The refrigerant compressor according to claim 48, wherein, by way of the processor, according to the values of the ambient temperature sensor, the base module controls a blower unit of the high pressure-side heat exchanger on the basis of specifications stored in the memory store or specifications determined by the processor according to further operating state variables.

50. The refrigerant compressor according to claim 1, wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a refrigeration location temperature sensor as a status acquisition unit and wherein the base module detects the values of the refrigeration location temperature sensor.

51. The refrigerant compressor according to claim 50, wherein, by way of the processor, the base module compares the refrigeration location temperature with reference values specified in the memory store or determined by the processor on the basis of further operating state variables.

52. The refrigerant compressor according to claim 51, wherein, by way of the processor, the base module controls a mass flow control unit in the refrigerant circuit, while taking account of the refrigeration location temperature and a control program stored in the memory store.

53. The refrigerant compressor according to claim 1, wherein the base module is configured to execute a lubricant return operation controlled by the processor in accordance with a lubricant return program, and wherein in particular at least one of i) the base module and ii) the additional module of the control unit is connected to a switchable output to activate the lubricant return operation as an operating unit and wherein the base module controls the output.

54. The refrigerant compressor according to claim 1, wherein, on occurrence of damage-prone operating states, the base module detects them by way of the processor and stores an alarm signal and wherein at least one of i) the base module and ii) the additional module of the control unit is connected to a display unit as an operating unit and wherein the base module controls the display unit such that it displays an alarm signal recognized by the base module.

55. A refrigerant circuit comprising at least one refrigerant compressor, a high pressure line extending away from the at least one refrigerant compressor, a high pressure-side heat exchanger arranged in the high pressure line, at least one expansion element following the high pressure-side heat exchanger in the high pressure line, a low pressure-side heat exchanger which is arranged in a low pressure line following the expansion element and from which the low pressure line extends to the at least one refrigerant compressor, wherein the at least one refrigerant compressor is configured having a compressor unit which draws in refrigerant with a suction port, compresses it and delivers it by way of a pressure port, wherein the refrigerant compressor has an electrical drive unit driving the compressor unit and wherein the refrigerant compressor is provided with a control unit which cooperates with at least one of i) operating units and ii) status acquisition units associated with the refrigerant compressor or the refrigerant circuit.

56. The refrigerant circuit according to claim 55, wherein it comprises a high pressure sensor arranged in the high pressure line.

57. The refrigerant circuit according to claim 55, wherein the refrigerant circuit comprises a lubricant separator arranged in the high pressure line.

58. The refrigerant circuit according to claim 55, wherein it comprises a mass flow control unit connected upstream of the expansion element.

59. The refrigerant circuit according to claim 55, wherein it comprises a refrigeration location temperature sensor.

60. The refrigerant circuit according to claim 55, wherein it comprises a system controller which cooperates with the control unit of the at least one refrigerant compressor.

61. The refrigerant circuit according to claim 60, wherein the system controller cooperates with the base module of the at least one refrigerant compressor.

62. The refrigerant circuit according to claim 60, wherein the system controller cooperates with a BUS terminal unit of the base module.

63. The refrigerant circuit according to claim 60, wherein the system controller cooperates wirelessly with the base module.

64. The refrigerant circuit according to claim 55, wherein a plurality of refrigerant compressors are provided, each refrigerant compressor having a compressor unit which draws in refrigerant with a suction port, compresses it and delivers it by way of a pressure port, wherein the refrigerant compressor has an electrical drive unit driving the compressor unit and wherein the refrigerant compressor is provided with a control unit which cooperates with at least one of i) operating units and ii) status acquisition units associated with the refrigerant compressor or the refrigerant circuit, wherein the control unit comprises a base module which has at least one processor and at least one memory store for the required program code and data for operating the processor and also terminals for operating units carrying out at least one of i) basic functions and ii) status acquisition units and wherein the processor and the program code stored in the memory store are configured so that operating units carrying out additional functions by way of an additional module connectable to at least one of i) the base module and ii) status acquisition units are also operable with these.

65. The refrigerant circuit according to claim 64, wherein the refrigerant compressors are connected in parallel in the refrigerant circuit.

66. The refrigerant circuit according to claim 64, wherein the control units of the refrigerant compressors communicate by way of the respective base module.

67. The refrigerant circuit according to claim 64, wherein the system controller cooperates directly with the respective control unit of the refrigerant compressor.

68. The refrigerant circuit according to claim 64, wherein the system controller cooperates with the control unit of one of the refrigerant compressors and this control unit in turn cooperates with the other control units.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0190] FIG. 1 shows a first exemplary embodiment of the refrigerant circuit according to the invention;

[0191] FIG. 2 shows an exemplary embodiment of a refrigerant compressor according to the invention;

[0192] FIG. 3 shows a view of a housing base of a controller housing of a control unit according to the invention;

[0193] FIG. 4 shows a plan view onto a housing base of the controller housing with a base module installed;

[0194] FIG. 5 shows a view of the housing base of the controller housing with a base module and an additional module installed;

[0195] FIG. 6 shows a side view of a refrigerant compressor according to the invention with a first exemplary embodiment of a control unit according to the invention arranged thereon, comprising exclusively one base module together with function units connected to the base module;

[0196] FIG. 7 shows a representation similar to FIG. 6 with a second exemplary embodiment of a control unit according to the invention, comprising a base module and a first exemplary embodiment of an additional module;

[0197] FIG. 8 shows a representation similar to FIG. 7 of a refrigerant compressor with a third exemplary embodiment of a control unit according to the invention, comprising a base module and a second exemplary embodiment of an additional module;

[0198] FIG. 9 shows a representation of different operating limits of an exemplary embodiment of a refrigerant compressor according to the invention;

[0199] FIG. 10 shows a representation similar to FIG. 8 of a refrigerant compressor with a fourth exemplary embodiment of a control unit according to the invention, comprising a base module and a third exemplary embodiment of an additional module;

[0200] FIG. 11 shows a representation similar to FIG. 6 of a refrigerant compressor with the fifth exemplary embodiment of a control unit according to the invention, comprising a base module to which a frequency converter is also connected;

[0201] FIG. 12 shows a representation similar to FIG. 7 of a refrigerant compressor with a sixth exemplary embodiment of a control unit according to the invention, comprising an additional module to which a frequency converter is connected;

[0202] FIG. 13 shows a representation similar to FIG. 1 of a second exemplary embodiment of a refrigerant circuit according to the invention;

[0203] FIG. 14 shows a representation similar to FIG. 13 of a third exemplary embodiment of a refrigerant circuit according to the invention; and

[0204] FIG. 15 shows a representation similar to FIG. 13 of a fourth exemplary embodiment of a refrigerant circuit according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0205] A first exemplary embodiment shown in FIG. 1 of a refrigerant circuit 10 according to the invention comprises a refrigerant compressor identified overall as 20, from the pressure port 22 of which a high pressure line 12 extends through a high pressure-side heat exchanger 14 in which the refrigerant is cooled, in particular condensed, and then passes to an expansion element 15 in which the refrigerant is expanded to a low pressure and is passed by a low pressure line 16 through a low pressure-side heat exchanger 18 in which the refrigerant expands, in particular evaporates and absorbs heat by means of expansion. The refrigerant leaving the low pressure-side heat exchanger 18 is then fed by the low pressure line 16 to a suction port 24 of the refrigerant compressor 20.

[0206] The pressure port 22 and the suction port 24 are associated with a compressor unit of the refrigerant compressor 20 identified overall as 26, in which the refrigerant drawn in through the suction port 24 is compressed, wherein the compressor unit 26 is configured, for example, as a reciprocating piston compressor.

[0207] Additionally, the compressor unit 26 is driven by an electrical drive unit identified overall as 28, in particular an electric motor.

[0208] The control of the refrigerant circuit 10 takes place by means of a system controller 30 or system regulation which controls, firstly, for example, a blower unit 32 of the high pressure-side heat exchanger 14 and, secondly, the expansion element 15 and furthermore also controls the refrigerant compressor 20 in that the system controller 30 cooperates with the motor supply unit 34 arranged on the electrical drive unit 28.

[0209] The motor current supply unit 34 is directly associated with a control unit 40 with which operating units and status acquisition units for the refrigerant compressor 20 and also the refrigerant circuit 10 are operated, in order, firstly, to monitor the operation of the refrigerant compressor 20 and, secondly, to optimize the operating conditions (FIG. 2).

[0210] The motor current supply unit 34 itself comprises a housing 36 which is arranged directly on the electrical drive unit 28, in particular on a drive housing 29 thereof accommodating said drive unit.

[0211] Seated on the housing 36 is a controller housing 42 of the control unit 40 (FIG. 2) protecting the control unit 40 according to the respective protective requirements by way of an encapsulation, said control unit cooperating with the motor supply unit 34.

[0212] The controller housing 42 therein comprises a housing base 44 (shown in FIG. 3) which is seated directly on the housing 36 and which represents, in particular, a bottom of the controller housing 42, wherein the housing base 44 is provided with a vibration-damping structure 46, for example a honeycomb structure, which is elevated above a housing bottom 48 in order to prevent vibrations of the drive housing 29 being transmitted by means of the housing 36 of the motor supply unit 34 to the control unit 40.

[0213] The housing base 44 is further provided with reinforcements 52 and 54 which are configured, for example, as reinforcing webs 52, 54 elevated above the housing bottom and on which the control unit 40 lies in the mounted state.

[0214] Furthermore, the housing base 44 has mounting receptacles 56 for fixing the control unit 40.

[0215] In addition, an earthing terminal strip 58 is arranged on the housing base 44.

[0216] As FIG. 4 shows, in its basic version, the control unit 40 comprises a base module 60 which can be laid onto a portion of the reinforcements 52 and 54 and is fixable to a portion of the mounting receptacles 56.

[0217] Provided on the base module 60 for carrying out basic functions are terminals 62 and 64, to whichas described in detail belowoperating units and/or status acquisition units are connectable.

[0218] For example, the terminals 62 are mains voltage terminals, for example, for alternating current and the terminals 64 are low voltage terminals, for example, for direct current (FIG. 4).

[0219] In particular, at least a portion of the mains voltage terminals 62 is switchable by means of output stages 63 provided with switching units, in order to switch operating units on or off.

[0220] Furthermore, in particular, at least a portion of the low voltage terminals 64 is configured for operating status acquisition units and is partially provided with switchable or controllable output stages 65 and a portion of the low voltage terminals 64 further serves for acquisition of measurement values of the status acquisition units (FIG. 4).

[0221] Furthermore, the base module 60 also has an electrical connecting element 66 to which as shown in FIG. 5, an additional module 70 is connectable, which is also insertable into the controller housing 42 and therein, in addition to the base module 60, can be arranged lying on the reinforcements 52 and 54 and is also additionally mountable on the housing base 44 with a further portion of the mounting receptacles 56.

[0222] By means of the reinforcements 52 and 54 carrying both the base module 60 and also the additional module 70, the connection between the electrical connecting element 66 of the base module 60 and a corresponding electrical connecting element 72 of the additional module 70 is therefore also protected against mechanical loadings, in particular vibrations, such that the electrical connection thereby created by way of the connecting element 66 to the additional module 70 remains securely and reliably intact.

[0223] Alternatively, the possibly also exists of the connection between the base module 60 and the additional module 70 by way of plug-in strips provided in the controller housing 40.

[0224] Furthermore, the additional module 70 is also provided with electrical terminals 74 and 76, by means of which a connection to operating units and/or status acquisition units carrying out additional functions takes place.

[0225] For example, the terminals 74 are mains voltage terminals, for example, for alternating current and the terminals 76 are low voltage terminals, for example, for direct current.

[0226] In particular, at least a portion of the mains voltage terminals 74 is provided with switching units and is switchable by means of output stages 75 controlled by the base module 60 in order to switch operating units on or off.

[0227] Therein, for example, these mains voltage terminals 74 are additionally secured in order to prevent further-reaching disruptions in the event of damage to an operating unit.

[0228] Furthermore, in particular, at least one of the low voltage terminals 76 is configured to operate a status acquisition unit and is provided, for example, with an output stage 77 that is switchable or controllable by means of the base module 60 and a portion of the low voltage terminals 76 further serves for acquisition and passing-on of measurement values from status acquisition units to the base module 60.

[0229] Furthermore, both the base module 60 and also the additional module 70 are connected to earth with the earth terminal strip 58.

[0230] In that operating units and/or status acquisition units are connectable to the base module 60 for executing basic functions, the control unit 40 can be configured in a first exemplary embodiment such that it has only the base module 60 and thus is capable only for executing the basic functions.

[0231] The communication of the base module 60 with the system controller 30 takes place, for example, either in analog manner or by means of a BUS system by means of a BUS terminal 140.

[0232] For wireless communication with the system controller 30 and/or with configuration and/or readout devices and/or further base modules 60, each base module 60 is advantageously provided with a wireless communication unit 86 which transmits and receives information and/or data, for example by means of Bluetooth or WiFi.

[0233] Depending upon the application, the basic functions can now be extended, by installing an additional module 70, to operating units and/or status acquisition units carrying out additional functions which, depending upon the configuration of the additional module 70 and thus, depending upon the requirement for the respective refrigerant compressor 20, can be configured and combined in the respective refrigerant circuit 10.

[0234] Herein, the base module 60 is in a position to recognize an additional module 70 of this type as such.

[0235] For optimal operation of the additional module 70, another configuration of the base module 60 preferably also takes place.

[0236] In principle, however, the operation of the basic functions and the additional functions takes place by way of at least one processor 82 already provided in the base module 60 and at least one memory store 82 associated therewith, using program code and data stored in the memory store 84, such as reference values, operating state variables, etc., so that the respective additional module 70 carries out only one mediatory communication, in each case, between the base module 60 and the operating units and status monitoring units connected to the additional module 70 for carrying out the additional functions.

[0237] The communication of the respective additional module 70 with the base module 60 takes place internally or externally either wire-based in analog manner or by means of a BUS connection.

[0238] In particular, an internal connection between the base module 60 and the respective additional module 70 takes place by means of the connecting elements 66 and 72.

[0239] Alternatively, an external connection can take place by means of lines, for example, between the terminal units 140 and 144.

[0240] A further alternative provides that the communication of the base unit 60 with the additional module 70 takes place wirelessly between the communication unit 86 of the base module and the communication unit 87 of the respective additional module 70.

[0241] A mediatory communication of this type of the additional module 70 can comprise not only a transmitting of a signal, but possibly a signal conversion and/or a signal processing and/or an intelligent signal processing and/or an evaluating signal processing or even a passing-on of a control signal for the operation of output stages 75 and 77 according to the control specifications of the base module 60.

[0242] The additional module 70 does not, however, in any event carry out evaluating and/or control functions. These are reserved for the at least one processor 82 in the base module 60.

[0243] Thus, the respective additional modules 70 serve only, by way of the mediatory communication, to make available an optimal adaptation of a great variety of operating and/or status acquisition units for carrying out the additional functions, while, on the basis of the stored program code and the data, the base module 60 makes available all the evaluating and/or control possibilities for a great variety of additional functions and thus for all the combinations with additional modules 70.

[0244] In a first exemplary embodiment shown in FIG. 6 of a refrigerant compressor 20 according to the invention arranged in the refrigerant circuit 10 according to the invention, the control unit 40 comprises only the base module 60, as shown in FIG. 4.

[0245] The base module 60 controls with the processor 82 a configurable start sequence of the electrical drive unit 28 by controlling the motor current supply unit 34 which has switch elements needed for the start sequence. Thereby, an adaptation to a great variety of drive units 28 is possible.

[0246] In addition, a temperature sensor 88 for acquisition of the temperature of the electrical drive unit 28 is connected to the base module 60, so that, on overheating of the electrical drive unit 28, by comparing the measured temperature with a stored reference value, the base module 60 can switch the drive unit 28 off.

[0247] Therein, connected to the base module 60 is a lubricant sensor 92 which is arranged on the compressor unit 26, for example on the front side of an external housing 27 thereof and, as the lubricant level sensor, optically detects a lubricant level in a drive chamber of the compressor unit 26.

[0248] The signal indicating the lubricant level is therein evaluated by the at least one processor of the base module 60 and, if it falls below a threshold value, has the result that the processor 82 switches the drive unit 28 off in order to prevent damage to the compressor unit 26.

[0249] Furthermore, a sensor 94 is connected to the base module 60 for monitoring a temperature of the compressed gas at the pressure port 22, wherein the detected compressed gas temperature is also compared by the processor 82 of the base module 60 with a threshold value, on exceeding of which, for example on exceeding 150? Celsius, a switching off of the electrical drive unit 28 takes place.

[0250] However, the possibility also exists of providing, as a further threshold, a warning threshold, for example at 140? Celsius, so that if the warning threshold is undershot, the processor 82 of the base module generates a warning signal and transmits it, for example, to the system controller 30.

[0251] Furthermore, connected to the base module 60 is a high pressure sensor 96 which detects, for example, the pressure in the refrigerant circuit 10, in particular in the high pressure line 12, so that the processor 82 can compare this high pressure with a threshold value and, if this threshold is exceeded, either again switches the drive unit 28 off or at least communicates a warning signal to the system controller 30.

[0252] The base module 60 in turn controls one or more display units 90 which display, for example, a warning signal and/or a stopping of the drive units 28 due to an inadmissible operating state being recognized by the processor 82 and/or the start readiness of the control unit 40, and are visible through a window 91 in the controller housing 42 (FIG. 4).

[0253] Furthermore, provided in the compressor unit is a lubricant heater 98 which is operated by the base module 60 such that, when the drive unit 28 is switched off, it heats the lubricant and then, when the drive unit 28 is in operation again, switches off the heating for the lubricant in order to keep the lubricant at a desired viscosity.

[0254] The base module 60 therein operates, in particular, the lubricant sensor 92, the compressed gas temperature sensor 94 and the high pressure sensor 96 with DC voltage, for example 12 Volt or 24 Volt.

[0255] Furthermore, the base module 60 operates the lubricant heater 98 with mains voltage, for example 110 Volt or 230 Volt, wherein an internal or a separate mains supply for the lubricant heater 98 is provided which the processor 82 switches on or off by means of one of the output stages 63.

[0256] In a second exemplary embodiment of the control unit 40 (FIG. 7), as FIG. 5 shows, it comprises the base module 60 and a first additional module 70.

[0257] The base module 60 can therein be configured in the same way and can be connected to the same sensors 92, 94, 96 as in the first exemplary embodiment according to FIG. 6.

[0258] Alternatively thereto, however, the possibility also exists, in place of the lubricant sensor 92, of using a lubricant sensor 93 that is configured as a continuous level sensor and enables a precise acquisition of the lubricant level.

[0259] Additionally, a lubricant injection unit 102 connected to the additional module 70 is also provided which injects lubricant according to the lubricant level measured by the lubricant sensor 93, said lubricant originating from a lubricant separator 104 which is arranged in the high pressure line 12 of the refrigerant circuit 10, following the pressure port 22, so that the processor 82 feeds lubricant to the compressor unit 26 according to the lubricant level determined by the lubricant sensor 93, for example, in defined intervals from the lubricant separator 104, by way of the lubricant injection unit 102, wherein this takes place making use of the fact that the lubricant is under high pressure in the lubricant separator 104 and thus, due to the high pressure, can easily be injected into the drive chamber of the compressor unit 26.

[0260] Furthermore, a power control unit 106 associated with at least one cylinder bank 105 of the compressor unit 26 is also connected to the additional module 70, said power control unit comprising, in particular, at least one power controller valve which, for example, in the cylinder bank 105, interrupts a feed of refrigerant to a suction chamber or short-circuits an outlet chamber to the corresponding suction chamber so that this cylinder bank 105 contributes no mass flow to the mass generated by the refrigerant compressor 20.

[0261] It is, however, also provided in the context of the invention to control individual cylinders, each with an associated power control unit 106.

[0262] It is, however, also conceivable to switch a plurality of cylinder banks 105 on or off individually with the additional module 70 of the control unit 40 to vary the mass flow and thus to control the power on a plurality of levels with regard to the mass flow of the refrigerant compressor 20.

[0263] The control of the at least one power controller unit 106 or a plurality of power controller units 106 therein takes place by means of the processor 82 of the base module 60, which transmits the control signals to the additional module 70, which then undertakes the respective control of the at least one power controller unit 106.

[0264] The processor 82 of the base module 60 therein reacts, for example, to demand signals from the system controller 30, which demands the required mass flow in the refrigerant circuit 10.

[0265] Furthermore, in this second exemplary embodiment, it is also provided that the additional module 70 controls a head fan 108 which represents a blower that serves for blower cooling of cylinder heads, for example of the cylinder banks 105 of the compressor unit 26 in order to prevent overheating of the compressor in the region of the cylinder heads and, in particular, the pressure port 22.

[0266] It is also optionally provided that an injection unit 110 for liquid refrigerant is arranged on the refrigerant compressor 20 such that it cools the refrigerant drawn in by the compressor unit 26 in the region of suction chambers thereof by expansion, in order to reduce the compressed gas temperature.

[0267] This injection unit 110 is connected to the additional module 70 and is controlled, for example, by the processor 82 of the base module 60, on evaluation of the compressed gas temperature at the compressed gas port 22, in the same way as the head fan 108.

[0268] In a further exemplary embodiment of a refrigerant circuit 10 according to the invention with a refrigerant compressor 20 according to the invention, in a third exemplary embodiment of the control unit 40, shown in FIG. 8, the base module 60 is configured as described in relation to the second exemplary embodiment according to FIG. 7, and the additional module 70 is connected to the same units as the additional module 70 according to FIG. 7, wherein the additional module 70 is additionally connected to the power controller unit 106 with further power controller units 106, 106 in order to carry out a more accurate power regulation and also to achieve a start loading relief similarly by means of at least one of the power controller units 106, 106 and 106.

[0269] The power controller units 106 or 106, 106 and 106 are preferably used such that a power regulation between 10% and 100% of the mass flow is possible.

[0270] This takes place, for example, by means of pulse width modulation, in particular with a high switching frequency at which the power controller units 106, 106 and 106 are controlled by the processor 82 according to a pre-programmed control logic stored in the memory store 84 in order to achieve the most stable possible control of the operation of the refrigerant compressor 20 but also, furthermore, to be able to react rapidly to load changes.

[0271] In particular, however, the power regulation also comprises a monitoring of the refrigerant compressor 20 on the basis of the signal solely of the compressed gas temperature sensor 94 which, if a threshold value for the compressed gas temperature is exceeded, causes the processor 82 to increase the mass flow through the refrigerant compressor 20 according to a predetermined operating program stored in the memory store 84 by means of suitable control of the power controller unit 106 or the power controller units 106, 106, 106, and thereby to reduce the compressed gas temperature again.

[0272] In addition, the additional module 70 is also connected to a suction gas temperature sensor 112 which detects the temperature of the drawn-in refrigerant, which temperature can then be communicated by way of the additional module 70 to the base module 60.

[0273] The processor 82 is thus able to compare the suction gas temperature with a threshold value to check whether it is high enough so that no liquid refrigerant enters into the compressor unit 26 of the refrigerant compressor 20 and, given too low a suction gas temperature, to transmit a warning signal to the system controller 30.

[0274] Another possibility consists therein that the processor 82 compares both the suction gas temperature measured by the suction gas temperature sensor 112 as well as the compressed gas temperature measured by the compressed gas temperature sensor 94 with the operating limits E specified in the memory store 84 for the operation of the refrigerant compressor 20.

[0275] Alternatively, the possibility exists of drawing upon values of a high pressure sensor and a suction pressure sensor for monitoring the operating limits E.

[0276] Such operating limits E are, for example, as shown in FIG. 9, an operating limit E1 which has the result that the processor 82 communicates a warning to the system controller 30.

[0277] Furthermore, for example, an operating limit E2 is provided which has the result that if the refrigerant compressor 20 is not operated again within the operating limit E1 within a particular time period, a switch-off of the refrigerant compressor 20 takes place or an operating limit E3 is provided which has the result that the refrigerant compressor 20 is immediately switched off by way of the processor 82.

[0278] In addition, for example, an operating limit E4 is provided, the undershooting of which has the result that all the preceding warnings regarding an exceeding of the operating limits E1 or E2 are deleted.

[0279] Furthermore, the additional module 70 is also connected to an ambient temperature sensor 114 which communicates an ambient temperature to the processor 82 so that the processor is able to monitor further and, if necessary, adapt the operating conditions for the refrigerant compressor 20.

[0280] In addition, the possibility also exists that, by means of a comparison of the ambient temperature with stored reference values and by way of the connection of the additional module 70 to the blower unit 32 of the high pressure-side heat exchanger 14, the processor 82 switches on this blower unit 32 independently of the system controller 30.

[0281] Furthermore, in the second exemplary embodiment of the additional module 70 it is also provided that, by means of the lubricant sensor 92 as described in relation to the exclusive use of the base module according to FIG. 6, it also monitors a lubricant level.

[0282] In a fourth exemplary embodiment of a control unit 40 according to the invention shown in FIG. 10, the base module 60 is configured identically to the first exemplary embodiment of the control unit 40 according to the invention.

[0283] However, the lubricant sensor 91 is a lubricant differential pressure sensor which detects a pressure difference in the lubricant supply to the compressor unit 26 and thus transmits to the base module 60 values regarding the quality of the lubricant supply to the compressor unit 20.

[0284] If the processor 82 recognizes by means of a comparison with reference values stored in the memory store 84, a deficit in the lubricant supply, then the processor 82 temporarily operates the refrigerant compressor 20 at full load, that is at maximum mass flow, in order thereby to achieve a sufficient lubricant return.

[0285] The additional module 70 is also configured so that it is connected to the power controller unit 106 and to the suction gas temperature sensor 112 and thereby the processor 82 of the base module 60 is capable, on the one hand, of comparing the suction gas temperature with a threshold value and, on the other hand, of determining whether the refrigerant compressor 20 is being operated in the region of its operating limits E1 to E4.

[0286] Furthermore, the additional module 70 is connected to the ambient temperature sensor 114 and thus the processor 82 of the base module 60 is capable of operating the blower unit 32 while taking account of the ambient temperature and possibly the high pressure.

[0287] Additionally, the possibility exists of connecting this additional module 70 to a refrigeration location temperature sensor 116 which detects the temperature of the site to be cooled by means of the low pressure-side heat exchanger 18 and thus opens the possibility, when this temperature is communicated by the additional module 70 to the processor 82 of the base module 60, that the processor 82 temporarily or permanently takes over the control functions of the refrigerant circuit, in particular of the system controller 30, and controls the power level of the refrigerant compressor 20, in particular its mass flow, according to the temperature measured by the refrigeration location temperature sensor 116 with the specification of a control program stored in the memory store 84.

[0288] Furthermore, the additional module 70 is connected to a display of a lubricant return operation 118 which enables lubricant to be fed back to the refrigerant compressor 20 in that the refrigerant compressor 20 is operated during a predetermined time period by means of the processor 82 and of a lubricant return program stored in the memory store 84 at full load, that is at maximum mass flow. For example, the lubricant return operation is initiated by the processor 82 if a lubricant deficit is recognized by the processor 82 by way of one of the lubricant sensors.

[0289] Furthermore, the additional module 70 is connected to a mass flow control unit 122 which is arranged on the high pressure side of the expansion element 15 and enables the mass flow passing through the expansion organ 15 to be controlled by the processor 82 according to a control program specified in the memory store 84.

[0290] Furthermore, the additional module 70 is also connected to a display unit 124 which serves to display whether any fault-prone operating state has been recognized by the processor 82 or whether an alarm-free operation of the refrigerant compressor 20 is underway and possibly also for indication on the display 118 of whether a temporary operation of the refrigerant compressor 20 takes place at full load for lubricant return.

[0291] A fifth exemplary embodiment of a refrigerant compressor 20 according to the invention, shown in FIG. 11, is provided with a frequency converter 130 for the electrical drive unit 28, which in this exemplary embodiment of the control unit 40 is connected to the base module 60, for example, by way of a BUS terminal unit 140, preferably by way of its BUS terminal 142 and is thus controllable by means of the processor 82, so that by means of the frequency converter 130 the mass flow of the refrigerant and thus the power level of the refrigerant compressor 20 in the refrigerant circuit 10 is controllable.

[0292] Alternatively, however, it can also be provided in a sixth exemplary embodiment of the control unit 40, shown in FIG. 12, to operate the frequency converter 130 in addition to one or more of the operating units or status acquisition units described above, by way of the respective additional module 70, for example, the BUS terminal unit 144, wherein in this case an operation of the power control units 106 for controlling the mass flow in this refrigerant compressor 20 can be omitted or even possibly be additionally provided.

[0293] In the exemplary embodiments of the control unit 40 described above, the communication between them and the system controller 30 is either by way of a direct line or by way of the BUS terminal unit 140 or by way of the wireless communication unit 86 of the respective base module 60.

[0294] The BUS terminal units 140 and 144 and the communication units 86, 87 serve in particular however not only for communication with the system controller 30, but are also usable for communication with other base modules 60 or additional modules 70 or configuration or readout units in order to read in or read out program code and/or data.

[0295] In the exemplary embodiments of the refrigerant circuit 10 according to the invention described so far, it comprises only one refrigerant compressor 20.

[0296] It is, however, also conceivable in a further exemplary embodiment, as shown in FIG. 13, to use a plurality of refrigerant compressors 201, 202, 203 connected in parallel, each to one control unit 401, 402, 403 according to one of the above exemplary embodiments, which in this exemplary embodiment and all further exemplary embodiments is configured according to one of the exemplary embodiments described above.

[0297] A first possibility for the communication between the system controller 30 and the control units 401, 402 and 403 provides that the system controller 30 of each of the control units 401, 402 and 403 transmits a start/stop signal in analog or digital manner and transmits a target value specification in analog manner so that the system controller 30 of each of the control units 401, 402 and 403 controls the respective refrigerant compressor according to these specifications.

[0298] Alternatively, however, the possibility exists for each base module 60 of the system controller 30 to control the BUS terminal unit 1401, 1402, 1403 at its BUS terminal 141, wherein specifications regarding the mass flow are then transmitted to each of the refrigerant compressors 201, 202, 203 by the system controller 30 by way of the BUS terminal 141, but otherwise each refrigerant compressor 201, 202, 203 is controlled independently of the other refrigerant compressors 201, 202, 203 by means of the respective base module 601, 602, 603.

[0299] Otherwise, the refrigerant compressor 20 and the refrigerant circuit 10 are configured in the same manner as in the previous exemplary embodiments.

[0300] In a further exemplary embodiment, shown in FIG. 14, the system controller 30 is connected, for example, by means of a BUS system to the base module 60 of the control unit 401 by means of the terminal unit 140 and the base module 60 of this control unit 401 communicates with the base modules 60 of the control units 402 and 403 as lower-order control units 402 and 403, so that the entire communication with the system controller 30 takes place by means of the one interface of the base unit 60 of the control unit 401.

[0301] Otherwise, this exemplary embodiment is configured in the same manner as the exemplary embodiment according to FIG. 13.

[0302] In a further exemplary embodiment, shown in FIG. 15, the communication between the refrigerant compressors 201, 202, 203 is identical to that in the preceding exemplary embodiment according to FIG. 14, however, for example, one of the refrigerant compressors 201, 202, 203 or a plurality thereof is provided with a frequency converter 130 which is controlled by means of the control unit 401, 402, 403 associated with this refrigerant compressor 201, 202, 203.