Provided compressor control module, CCM, adapted to control an output of a
variable displacement swash plate compressor, it is an object of the present invention to improve the efficiency of the compressor. The object is solved by: either directly calculate, or receive from an
external source, for example the
HVAC control unit, a
signal indicating the desired or required output from the
variable displacement swash plate compressor (30), also referred to as control target or set value, for example, but not limited to, a suction pressure, a
piston stroke length, an
evaporator outlet
air temperature, a
refrigerant mass flow and / or a work done on fluid; receive the current / actual value of the value; receive or calculate the current rotation speed and angle, with respect to the rotation axis, of the
swash plate, or the current
piston stroke length and its reciprocating frequency, respectively, (48) of the
variable displacement swash plate compressor; receive or calculate optionally additional current values of the compressor, the
air conditioning system or from the vehicle, like the
discharge pressure, the
crank case pressure, the
delta pressure between suction pressure and
crank case pressure, the
evaporator outlet
air temperature, the engine speed, but not limited to; determine the difference between the desired or required output from the variable displacement swash plate compressor and the current output of the variable displacement swash plate compressor; and output a
signal to the valve driving unit which will adjust the angle of the swash plate (48) such that the actual output of the variable displacement swash plate compressor becomes closer to, or the same as, the desired or required output as obtained in step a), also taking into account the
additional values received or calculated in c) and d).