Analysis on constant power range enhancement in hybrid-inverter open winding PMSM drive system

This paper analyzes the constant power range enhancement in hybrid-inverter open winding Permanent Magnet Synchronous Motor (PMSM) drive system. With the support of controllable reactive power from the conditioning inverter (CI), the main inverter (MI) is able to operate at unity power factor and the voltage supply is boosted. The relationship between the inverters´ voltage and the machine voltage is derived as a function of the motor power factor angle and the phase difference between two inverters´ voltage vectors. Furthermore, in order to select the appropriate capacitor voltage value, different capacitor voltage settings are analyzed to demonstrate the effectiveness of CI in hybrid-inverter drive system. Comprehensive analysis and simulation results have shown that, compared with the single-inverter drive system, the hybrid-inverter drive system has the ability to boost machine voltage and enhance the constant power range.