A novel single phase three-level power factor correction with passive lossless snubber

Multilevel conversion techniques, power factor correction techniques and soft switching techniques are the three research hot topics of power electronics. The paper finds an appropriate application object that embodies these trends and proposes a novel single phase there-level PFC circuit with passive lossless snubber. The three-level buck and boost topologies are derived from the traditional diode clamped three-level inverters' bridge leg firstly. Then, a single phase three-level PFC circuit is presented based on the three-level boost topology. The principle and implementation approaches of the three-level PFC circuit are described. Two passive lossless snubber cells are added to three-level PFC circuit to soften the switching processes of the switches and freewheeling diodes. It's operating principle and design considerations are discussed in detail. A 2 kW prototype of single phase three-level PFC with the passive lossless snubber is built and tested. The simulated and experimental results indicate that the circuit can realize the three-level PFC function and increase system efficiency as well as resulting in no overvoltage stress on main power switches. Moreover, the power factor of the circuit with the proposed passive lossless snubber is higher than that of the circuit without the snubber.