Control device and method for operating a refrigerant compressor

Abstract

Electronic control device for a refrigerant compressor, comprising at least one drive unit and a compression mechanism which is in operative connection with the drive unit and has at least one piston which, in an operating state of the refrigerant compressor, moves back and forth in a cylinder of a cylinder block of the refrigerant compressor for the operational compression of refrigerant and is driven by a crankshaft of the drive unit, wherein the electronic control device of the refrigerant compressor is at least designed to detect at least one physical process parameter, preferably the rotational speed (n) of the crankshaft or the power consumption of the refrigerant compressor, and to detect a switch-off signal directed at the refrigerant compressor, said switch-off signal terminating a refrigerant compressor operating phase in which the refrigerant compressor is operated as intended with a positive operating torque; and is also designed to regulate a torque applied by the drive unit to the crankshaft so as to adjust the rotational speed (n) of the crankshaft, wherein the electronic control device is further designed to apply a braking torque to the crankshaft immediately after detecting the switch-off signal, wherein the braking torque is applied in the opposite direction to the positive torque acting during the operating phase and the value of this braking torque is a function of the detected physical process parameter, preferably the rotational speed (n) of the crankshaft or the power consumption of the refrigerant compressor.

What is claimed is: 
     
         1 . An electronic control device for a refrigerant compressor, which comprises at least
 a drive unit and   a compression mechanism that is in operative connection with the drive unit and that has at least one piston that moves back-and-forth in a cylinder of a cylinder block of the refrigerant compressor in an operating state of the refrigerant compressor for compression of refrigerant as designed and is driven via a crankshaft of the drive unit   
       where the electronic control device of the refrigerant compressor is configured at least
 to detect at least one physical process parameter of the refrigerant compressor, 
 to detect a shutoff signal directed to the refrigerant compressor, which shutoff signal ends an operating phase of the refrigerant compressor, in which operating phase the refrigerant compressor is operated as designed with a positive operating torque, and 
 to control a torque applied by the drive unit to the crankshaft in order to set its rotary speed (n), 
 
       wherein the electronic control device is further configured to apply a braking torque to the crankshaft immediately after detection of the shutoff signal, where the braking torque is directed opposite to the positive torque that existed during the operating phase and the value of said braking torque is a function of the detected physical process parameter of the refrigerant compressor. 
     
     
         2 . The electronic control device as in  claim 1 , wherein the physical process parameter is the rotary speed (n) of the crankshaft. 
     
     
         3 . The electronic control device as in  claim 1 , wherein the value of the braking torque applied to the crankshaft immediately after detection of the shutoff signal is inversely proportional to the rotary speed (n) of the crankshaft that the crankshaft has at the moment of the detection of the shutoff signal. 
     
     
         4 . The electronic control device as in  claim 1 , where the braking torque is maintained up to a complete stop of the crankshaft. 
     
     
         5 . The electronic control device as in  claim 1 , wherein the braking torque applied to the crankshaft is realized as a braking profile, where a function defining the course of the braking profile is stored by the electronic control device. 
     
     
         6 . The electronic control device as in  claim 1 , wherein the electronic control device is configured to compare the rotary speed (n) of the crankshaft with preset rotary speed values (n α , n β , . . . ) in a braking time extending between the detection of the shutoff signal and the complete stop of the crankshaft. 
     
     
         7 . The electronic control device as in  claim 6 , wherein the course of the braking profile essentially follows a piecewise linear function, where a segment of the braking time is associated with each of the preset rotary speed values (n α , n β , . . . ), within which segment said piecewise linear function exhibits an essentially constant slope. 
     
     
         8 . The electronic control device as in  claim 5 , wherein the value of the braking torque resulting from the course of the braking profile increases monotonously from the time of the detection of the shutoff signal to the time of the complete stop of the crankshaft. 
     
     
         9 . A refrigerant compressor for use in a refrigeration unit where the refrigerant compressor comprises an electronic control device as in  claim 1 . 
     
     
         10 . A refrigeration unit with a refrigerant compressor as in  claim 9 . 
     
     
         11 . A method for operating a refrigerant compressor suitable for use in a refrigeration unit, which comprises a compression mechanism for compression of refrigerant and a drive unit, where the compression mechanism is driven by means of a crankshaft of the drive unit that is supplied with a torque, wherein the method comprises the following steps:
 detection of a shutoff signal ending an operating phase in which the refrigerant compressor is operated as designed with a positive operating torque;   detection of a physical process parameter of the refrigerant compressor;   a application of a braking torque to the crankshaft immediately after the detection of the shutoff signal, where the braking torque opposes the positive operating torque in its direction of action and the value of the braking torque is a function of the detected physical process parameter of the refrigerant compressor.   
     
     
         12 . The method as in  claim 11 , wherein the physical process parameter is the rotary speed (n) of the crankshaft. 
     
     
         13 . The method as in  claim 11 , wherein the value of the braking torque applied to the crankshaft immediately after detection of the shutoff signal is essentially inversely proportional to the rotary speed (n) of the crankshaft that the crankshaft has at the moment of the detection of the shutoff signal. 
     
     
         14 . The method as in  claim 11 , wherein the braking torque is maintained at least in a segment within a braking time, where the braking time is the time between the detection of the shutoff signal and the complete stop of the crankshaft. 
     
     
         15 . The method as in  claim 14 , wherein the braking torque is applied to the crankshaft in the form of a braking profile, where a function defining the course of the braking profile is stored by the electronic control device. 
     
     
         16 . The method as in  claim 15 , wherein the value of the braking torque resulting from the course of the braking profile increases monotonously from the tune of the detection of the shutoff signal to the time of the complete stop of the crankshaft. 
     
     
         17 . The method as in  claim 14 , wherein during the braking time the rotary speed (n) of the crankshaft is compared with preset rotary speed values (n α , n β , . . . ) and the braking time is divided at least partially, into process time segments (T α , T β , . . . ), where in each of said process time segments (T α , T β , . . . ) the rotary speed (n) of the crankshaft lies in a value range with which one of the preset speed values (n α , n β , . . . ) is associated. 
     
     
         18 . The method as in  claim 17 , wherein the course of the braking profile essentially follows a piecewise linear function of the process time, where said function exhibits a segment with constant slope in each process time segment (T α , T β , . . . ). 
     
     
         19 . The electronic control device of  claim 1  wherein the at least one physical process parameter comprises one or more of:
 rotary speed (n) of the crankshaft, and power consumption of the refrigerant compressor. 
 
     
     
         20 . The electronic control device as in  claim 5 , wherein the function defining the course of the braking profile comprises a linear dependency on the current rotary speed (n) of the crankshaft and/or the time elapsed since detection of the shutoff sign. 
     
     
         21 . The electronic control device of  claim 6 , wherein the electronic control device is configured to compare the rotary speed (n) of the crankshaft a number of times with preset rotary speed values (n α , n β , . . . ) in a braking time extending between the detection of the shutoff signal and the complete stop of the crankshaft. 
     
     
         22 . The electronic control device as in  claim 21 , wherein the electronic control device is configured to compare the rotary speed (n) of the crankshaft continuously with preset rotary speed values (n α , n β , . . . ) in a braking time extending between the detection of the shutoff signal and the complete stop of the crankshaft. 
     
     
         23 . The refrigerant compressor as in  claim 9 , wherein the refrigeration unit comprises a refrigerator or freezer. 
     
     
         24 . The method as in  claim 11 , wherein the physical process parameter comprises one or more of: rotary speed of the crankshaft, and power consumption. 
     
     
         25 . The method as in  claim 14 , wherein the braking torque is maintained up to the complete stop of the crankshaft. 
     
     
         26 . The method as in  claim 15 , wherein the function defining the course of the braking profile comprises a linear dependency on the current rotary speed (n) of the crankshaft and/or of the elapsed time since detection of the shutoff signal. 
     
     
         27 . The method as in  claim 17 , wherein the rotary speed (n) of the crankshaft is compared a number of times with the preset rotary speed values (n α , n β , . . . ). 
     
     
         28 . The method as in  claim 26 , wherein the number of times is continuously with the preset rotary speed values (n α , n β , . . . ). 
     
     
         29 . The method as in  claim 17 , wherein the entire braking time is divided into process time segments (T α , T β , . . . ).