A control system for a rotary compressor driven by a rotary engine, said control system comprising: A) a first control subsystem comprising: - a performance input arranged to receive a first measure signal indicating performance of said rotary compressor, - a speed input arranged to receive a second measure signal indicating rotation speed of said rotary compressor or said rotary engine, and - a first control output arranged to provide a first control signal as a function of said first measure signal and said second measure signal; B) a second control subsystem comprising: - a performance input arranged to receive a third measure signal indicating performance of said rotary compressor, and - a second control output arranged to provide a second control signal as a function of said third measure signal; characterised in that said control system further comprises: C) a selector comprising: - a first input electrically connected to said first control output, - a second input electrically connected to said second control output, and - a third control output arranged to provide a third control signal to a power control input of said rotary engine, wherein said selector is arranged to select said first control signal or said second control signal as said third control signal to be provided at said third control output. A) a first control subsystem comprising: - a performance input arranged to receive a first measure signal indicating performance of said rotary compressor, - a speed input arranged to receive a second measure signal indicating rotation speed of said rotary compressor or said rotary engine, and - a first control output arranged to provide a first control signal as a function of said first measure signal and said second measure signal; - a performance input arranged to receive a first measure signal indicating performance of said rotary compressor, - a speed input arranged to receive a second measure signal indicating rotation speed of said rotary compressor or said rotary engine, and - a first control output arranged to provide a first control signal as a function of said first measure signal and said second measure signal; B) a second control subsystem comprising: - a performance input arranged to receive a third measure signal indicating performance of said rotary compressor, and - a second control output arranged to provide a second control signal as a function of said third measure signal; characterised in that said control system further comprises: - a performance input arranged to receive a third measure signal indicating performance of said rotary compressor, and - a second control output arranged to provide a second control signal as a function of said third measure signal; C) a selector comprising: - a first input electrically connected to said first control output, - a second input electrically connected to said second control output, and - a third control output arranged to provide a third control signal to a power control input of said rotary engine, - a first input electrically connected to said first control output, - a second input electrically connected to said second control output, and - a third control output arranged to provide a third control signal to a power control input of said rotary engine,