Control Device For A Compressor, A Compressor With The Same, And An Air Conditioning System Including Control Device And Compressor

Abstract

A compressor control module (CCM) controls an output of a variable displacement swash plate compressor. The CCM directly calculates, or receives from an external source, a signal indicating a desired or required output from the compressor, receives a current value of the desired or required output, and receives or calculates a current rotation speed and angle, with respect to a rotation axis, of a swash plate, or a current piston stroke length and a reciprocating frequency of the compressor. The CCM determines a difference between the desired or required output from the compressor and the current value and outputs a signal to a valve driving unit which will adjust an angle of a swash plate such that the actual value becomes closer to, or the same as, the desired or required output, taking into account the additional values received or calculated in the receives or calculates step.

What is claimed is: 
     
         1 . A compressor control module adapted to control an output of a variable displacement swash plate compressor, wherein the compressor control module:
 directly calculates, or receives from an external source, a signal indicating a desired or required output from the variable displacement swash plate compressor;   receives a current value of the desired or required output;   receives or calculates a current rotation speed and angle, with respect to a rotation axis, of a swash plate, or a current piston stroke length and a reciprocating frequency of the variable displacement swash plate compressor;   determines a difference between the desired or required output from the variable displacement swash plate compressor and the current value; and   outputs a signal to a valve driving unit which will adjust an angle of a swash plate such that the actual value becomes closer to, or the same as, the desired or required output, taking into account the additional values received or calculated in the receives or calculates step.   
     
     
         2 . The compressor control module of  claim 1 , wherein the external source is a heating ventilation and air conditioning control unit. 
     
     
         3 . The compressor control module of  claim 1 , wherein the desired or required output from the variable displacement swash plate compressor is a suction pressure, a piston stroke length, an evaporator outlet air temperature, a refrigerant mass flow and/or a work done on a fluid. 
     
     
         4 . The compressor control module of  claim 1 , wherein the compressor control module receives or calculates additional current values of the variable displacement swash plate compressor, an air conditioning system, or from a vehicle, such as a discharge pressure, a crank case pressure, a delta pressure between a suction pressure and a crank case pressure, an evaporator outlet air temperature, and/or an engine speed. 
     
     
         5 . The compressor control module of  claim 1 , wherein the steps are repeated in the claimed sequence until the current value is closer to, or the same as, the desired or required output. 
     
     
         6 . The compressor control module of  claim 1 , wherein the desired or required output is manipulated based on the additional values received or calculated in the receives or calculates step. 
     
     
         7 . The compressor control module of  claim 1 , wherein an upper and/or a lower threshold difference between a crank chamber pressure and a suction pressure difference, exceeding the upper threshold results in an swash plate angle increase and undershooting the lower threshold results in a swash plate angle decrease, is stored while a derivative of piston stroke length is different from zero or different from a certain tolerance band around zero, the upper and/or lower threshold difference or a function of the upper and/or lower threshold difference is used for swash plate angle control. 
     
     
         8 . The compressor control module of  claim 1 , wherein a compressor rotation speed and/or derivatives of the compressor rotation speed are fed forward to the compressor control module in order to adjust an input and/or an output of one and/or more than one controller loops to improve dynamic behavior in case of changes in compressor rotations per minute. 
     
     
         9 . The compressor control module of  claim 1 , wherein the signal to the valve driving unit is at least in part generated from an output of a Model Predictive Control, an Internal Model Controller, an online predictive controller like neural network, and/or a Multi-Input-Single-Output controller. 
     
     
         10 . The compressor control module of  claim 1 , wherein the signal to the valve driving unit is at least in part generated from an output of a PID controller, the determined difference is an input signal to the PID controller. 
     
     
         11 . The compressor control module of  claim 10 , wherein at least one gain parameter of the PID controller is at least in part adjusted based on one or more measured or calculated values of the compressor, the measured or calculated values are at least one of: a suction chamber pressure, a discharge chamber pressure, a piston stroke length, a piston reciprocating frequency, and opening level of a control valve. 
     
     
         12 . The compressor control module of  claim 11 , wherein, when the suction chamber pressure is low, a P-parameter and/or an I-parameter and/or a D-parameter is lower compared to when the suction chamber pressure is higher; and/or when the discharge chamber pressure is high, the P-parameter and/or the I-parameter and/or the D-parameter is lower compared to when discharge chamber pressure is lower; and/or when the piston stroke length is low, the P-parameter and/or the I-parameter and/or the D-parameter is higher compared to when the piston stroke length is higher. 
     
     
         13 . A variable displacement swash plate compressor, comprising:
 a compressor control module adapted to control an output of the variable displacement swash plate compressor, the compressor control module:
 directly calculates, or receives from an external source, a signal indicating a desired or required output from the variable displacement swash plate compressor; 
 receives a current value of the desired or required output; 
 receives or calculates a current rotation speed and angle, with respect to a rotation axis, of a swash plate, or a current piston stroke length and a reciprocating frequency of the variable displacement swash plate compressor; 
 determines a difference between the desired or required output from the variable displacement swash plate compressor and the current value; and 
 outputs a signal to a valve driving unit which will adjust an angle of a swash plate such that the actual value becomes closer to, or the same as, the desired or required output, taking into account the additional values received or calculated in the receives or calculates step. 
   
     
     
         14 . The variable displacement swash plate compressor of  claim 13 , wherein the variable displacement swash plate compressor does not have a bleed port or a bleed valve between a suction chamber and a crank chamber or has a bleed port with a reduced diameter. 
     
     
         15 . The variable displacement swash plate compressor of  claim 13 , further comprising at least one speed-stroke sensor, the speed-stroke sensor monitors a piston stroke length and a reciprocating speed of one, or more, of a plurality of pistons of the variable displacement swash plate compressor and sends the measurement to the compressor control module. 
     
     
         16 . The variable displacement swash plate compressor of  claim 15 , wherein the compressor control module, on the basis of an amount of travel of the one of more pistons, calculates the angle of the swash plate and/or the piston stroke length of the variable displacement swash plate compressor and, on the basis of the reciprocating speed of the piston, calculates the swash plate and the compressor rotational speed. 
     
     
         17 . The variable displacement swash plate compressor of  claim 13 , further comprising an electronic control valve connected to the compressor control module and adapted, in response to receiving the output signal at the valve driving unit, to direct pressure from a crank chamber to one or more of a plurality of suction chambers or from a discharge chamber to the crank chamber, changing an angle of the swash plate. 
     
     
         18 . An air conditioning system, comprising:
 a variable displacement swash plate compressor including a compressor control module adapted to control an output of the variable displacement swash plate compressor, the compressor control module:
 directly calculates, or receives from an external source, a signal indicating a desired or required output from the variable displacement swash plate compressor; 
 receives a current value of the desired or required output; 
 receives or calculates a current rotation speed and angle, with respect to a rotation axis, of a swash plate, or a current piston stroke length and a reciprocating frequency of the variable displacement swash plate compressor; 
 determines a difference between the desired or required output from the variable displacement swash plate compressor and the current value; and 
 outputs a signal to a valve driving unit which will adjust an angle of a swash plate such that the actual value becomes closer to, or the same as, the desired or required output, taking into account the additional values received or calculated in the receives or calculates step. 
   
     
     
         19 . The air conditioning system of  claim 18 , wherein the air conditioning system is in an automobile and the compressor control module ensures that a temperature in a cabin of the automobile is maintained at a desired, or set, temperature by users of the automobile by controlling a suction pressure or an output of coolant of the variable displacement swash plate compressor. 
     
     
         20 . The air conditioning system of  claim 19 , wherein the desired output of the variable displacement swash plate compressor is an amount of work done on the coolant, and which remains constant irrespective of a driving force and rotation speed of the variable displacement swash plate compressor.