Synchronous motor-control apparatus and vehicle using the control apparatus

A digital calculation apparatus (4) including a position-detection means (14) for detecting the magnetic pole position, based on the detected current difference values of the synchronous motor (1) in a two-phase short-circuit state, takes in current flowing in the synchronous motor (1) by generating an interruption trigger signal in synchronization with the PWM signals for driving an inverter (3), and driving an A/D converter with the generated trigger signal.