A control system for an electric three-phase variable speed motor having a stator and rotor, the control system comprising an inverter for providing power to the electric motor, a scalar based control arrangement for controlling said inverter, and current sensors configured to repeatedly detect currents of the motor, wherein the control arrangement comprises: - a d and q axis currents determining module configured to repeatedly determine d and q axis currents (i sd, i sq) based on the detected currents; - a filter block for repeatedly filtering the determined q axis current, thereby generating a reference q axis current (i* sq); - an MTPA (maximum torque per ampere) control block for repeatedly generating a reference d axis current (i* sd) based on said determined d and q axis currents (i sd, i sq) and a ratio value such that the ratio of the d and q axis currents is equal to said ratio value, wherein said ratio value is unity, and - a switching signal generation module configured to repeatedly generate switching signals to control said inverter based on said reference d and q axis currents (i* sd, i* sq), characterized in that the control arrangement comprises - a fine adjustment module which is configured to calculate a magnitude of a current (|i|) or power (P*) of the motor and to determine an optimum compensation ratio value (K(sc)) based on the calculated magnitude of a current or power of the motor, which optimum compensation ratio value is added to the ratio value to form an adjusted ratio value (1+ K(sc)), which adjusted ratio value when being used by the MTPA control block would cause the motor to operate in a condition wherein the magnitude of a current or power of the motor is minimized, wherein - the MTPA control block is configured to repeatedly generate an adjusted reference d axis current (i* sd (adj)) based on said determined d and q axis currents (i sd, i sq) and said adjusted ratio value such that the ratio of the d and q axis currents is equal to said adjusted ratio value; and - the switching signal generation module is configured to repeatedly generate switching signals to control said inverter based on said adjusted reference d axis current. - a d and q axis currents determining module configured to repeatedly determine d and q axis currents (i sd, i sq) based on the detected currents; - a filter block for repeatedly filtering the determined q axis current, thereby generating a reference q axis current (i* sq); - an MTPA (maximum torque per ampere) control block for repeatedly generating a reference d axis current (i* sd) based on said determined d and q axis currents (i sd, i sq) and a ratio value such that the ratio of the d and q axis currents is equal to said ratio value, wherein said ratio value is unity, and - a switching signal generation module configured to repeatedly generate switching signals to control said inverter based on said reference d and q axis currents (i* sd, i* sq), characterized in that the control arrangement comprises - a fine adjustment module which is configured to calculate a magnitude of a current (|i|) or power (P*) of the motor and to determine an optimum compensation ratio value (K(sc)) based on the calculated magnitude of a current or power of the motor, which optimum compensation ratio value is added to the ratio value to form an adjusted ratio value (1+ K(sc)), which adjusted ratio value when being used by the MTPA control block would cause the motor to operate in a condition wherein the magnitude of a current or power of the motor is minimized, wherein - the MTPA control block is configured to repeatedly generate an adjusted reference d axis current (i* sd (adj)) based on said determined d and q axis currents (i sd, i sq) and said adjusted ratio value such that the ratio of the d and q axis currents is equal to said adjusted ratio value; and - the switching signal generation module is configured to repeatedly generate switching signals to control said inverter based on said adjusted reference d axis current.