A boost five-level inverter for wireless power transfer system

The paper proposed a boost five-level inverter for wireless power transfer (WPT) system. It consists of one DC source, one inductor, one capacitor, and six power switches. It can produce a five-level output with an amplitude twice that of the DC source voltage. Compared with the existing five-level inverters, the proposed topology needs fewer power switches and energy storage elements, as well as lower power switches total standing voltage. Firstly, this paper introduced the topology and operating principle of the proposed inverter, established the mathematical models of the inverter output voltage and the system output power, and compared the proposed inverter with the existing five-level inverters. On this basis, the level cascaded extension method and topology of the proposed inverter were introduced and analyzed. Then, the modulation strategy and parameters of the proposed inverter were designed. Furthermore, the power loss of the proposed inverter was calculated. Finally, simulation and experimental verification were conducted. The results show that the inverter efficiency can reach up to about 94.5%, and the output THD can be as low as 24.47% or even lower. In addition, the transient response time is within 4 ms, proving the feasibility and superiority of the proposed inverter applied to WPT systems.