In a driving system comprising a permanent magnet type synchronous machine, an electric power converter for the synchronous machine and a driving controller for driving the electric power converter, the driving controller comprises a current command generator for generating a d-axis current command and a q-axis current command of the synchronous machine, a d, q-axis current control uni for generating AC voltage command values Vu*, Vv* and Vw* based on the d-, q-axis currents from the synchronous machines, and a PWM control unit for generating driving signals for the electric power converter based on the AC voltage command values. A phase generator generates a phase signal from zero-cross point information of the AC voltage command values and a phase difference angle .delta. between induced voltage and terminal voltage of the synchronous machine; and a magnet temperature compensating unit generates a phase signal from zero-cross point information of the AC voltage command values and a phase difference angle .delta. of a .delta.-table storing phase difference angles .delta. between induced voltage and terminal voltage of the synchronous machine. The phase difference angle .delta. is compensated based on a magnet temperature.