PWM & PAM control strategy for five-level double converter

A three-phase five-level double converter, which we use in this study, consists of connecting a three-phase five-level rectifier and a three-phase five-level inverter. The five-level rectifier converts AC source power to DC power, and then the five-level inverter converts the DC power to variable-voltage and variable-frequency AC output power. The converter may help adjustable-speed drive of motors. We propose the PWM & PAM control strategy for the three-phase five-level double converter. The PWM & PAM control strategy carries out the operation as follows. In low motor speed areas, the rectifier fixes DC voltage at low value and the inverter outputs pulse width modulation (PWM) waveforms. In high speed areas, the rectifier adjusts DC voltage in proportion to the speed and the inverter outputs pulse amplitude modulation (PAM) waveforms. This strategy can reduce the generated losses at switching devices in the inverter circuit and the harmonic distortion of the inverter output current waveform.