Motor controlling device, motor drive system, method of motor control, semiconductor device and electronic device

A motor control device is disclosed which is arranged so as to perform a PWM control for a permanent magnet motor including a rotor having a permanent magnet and a stator with a multiphase winding. The motor control device includes a position detection unit which executes an analog computation process for induced voltages of respective phases of the motor based on a phase voltage equation having, as operation terms, respective phase voltages, respective phase currents, winding inductance, winding resistance and a neutral point voltage, the winding inductance and the winding resistance being motor constants of the motor, thereby generating and delivering a rotational position signal of the rotor based on a phase relation of the induced voltages, and a digital processing unit which has a function of generating and delivering a sinusoidal PWM signal based on the rotational position signal, thereby controlling the motor.