System Description
The resolver is a sensor that is used to detect the position of the magnetic poles of the rotor of the rear motor. Knowing the position of the poles is indispensable for ensuring precise control of the rear motor. Each resolver contains a stator that has an excitation coil and 2 detection coils (S, C). The gap between the stator and rotor changes as the rotor turns because the rotor is oval shaped. An alternating current with a predetermined frequency flows through the excitation coil, and detection coils S and C output alternating currents in accordance with the sensor rotor position.
The rear motor generator control ECU (MGR ECU), which is built into the EV motor control inverter assembly, detects the absolute position of the rotor according to the phases of detection coils S and C and the heights of their waveforms. Furthermore, the CPU calculates the amount of change in the position within a predetermined length of time, in order to use the resolver as a revolution speed sensor.
The rear motor generator control ECU (MGR ECU), which is built into the EV motor control inverter assembly, monitors signals output from the rear motor resolver and detects malfunctions.