Patent ID: 7439703

Claim:
A controller for a synchronous machine, comprising: a power converter which alternately converts direct current power and alternating current power, and receives gate commands; a synchronous machine driven by the power converter; a PWM modulation section which performs PWM modulation for a voltage command value for controlling the synchronous machine and outputs the gate commands to the synchronous machine, wherein a voltage applied to the synchronous machine is obtained by an operation from the gate commands; a current detection section which detects a current conducted to the synchronous machine at predetermined sampling timing; a first current variation operation section which operates a current variation during a time interval between timings synchronized with the detection sampling in the current detection section; a first voltage integration operation section which operates a voltage integration value during a time interval between the same timings as the timings in the first current variation operation section; a second current variation operation section defining, as one set, the current variation of the first current variation operation section and the voltage integration value of the first voltage integration operation section during the time interval between the same timings, and operating a current variation during a time interval in which all operation timings of a plurality of the sets are included; a second voltage integration operation section operating a voltage integration value during the same time interval as the time interval of the second current variation operation section; and a rotation phase angle assumption section which assumes a rotation phase angle of the synchronous machine by using the plurality of respective sets, the time intervals corresponding to the respective sets, the current variation and the voltage integration value during the time interval in which all the operation timings of the plural sets are included, and the time interval in which all the operation timings of the plural sets are included.