Quasi-resonant dc-link soft-switching PWM inverter with active feedback clamp circuit for motor drive applications

A novel soft-switched quasi-resonant dc-link (QRDCL) inverter topology is derived using the concept of an auxiliary switch-assisted soft-switcher (AASS) employing the flying capacitor. This concept is known for its high efficiency at high power levels, and is used for soft-switching the boost switch in zero-voltage transition (ZVT) power factor correction (PFC) boost rectifiers. Also, an active clamp circuit configuration to clamp the dc-link and recover the energy stored in the clamp capacitor is introduced and is applied to the proposed inverter topology. The resultant inverter configuration gives high efficiency and is suitable for high power motor drive applications. The maximum dc-link voltage is clamped at around (1.05-1.1) times the input dc-source voltage. The proposed inverter is suitable for pulse width modulation (PWM) operation. A detailed analysis along with the design procedure of the proposed inverter is presented. Simulation and laboratory experiments are carried out to validate the analysis.