PWAM controlled quasi-Z source motor drive

This paper proposes a novel pulse-width-amplitude-modulation (PWAM) method for three-phase quasi-Z source inverter system in motor drive application. It is demonstrated that it operates at only 1/3 switching frequency of traditional PWM methods, with less harmonic distortion. As a result, switching actions and losses are also reduced significantly. With the proposed modulation, the required capacitance is reduced greatly, which makes a system of smaller volume and lighter weight. Compared to traditional PWM methods, the higher efficiency and better reliability are confirmed in PWAM controlled motor drive system. The motor drive with the proposed hybrid PWAM modulation method presents good performance in simulation. Theoretical analysis is provided to verify the inverter efficiency and design improvements.