State plane analysis and soft switching condition of novel resonant DC link inverter

The novel resonant DC link voltage source inverter combined merits of pulse width modulation (PWM) and soft switching. However, auxiliary resonant DC link has a four-element LCCC structure, and it lead to inverter has complex transient dynamics, high dimension and time variation. It is difficult to obtain soft switching condition and design rule of inverter by means of differential equation. The state-plane analysis technique is established for the novel resonant DC link inverter in this paper. Making use of three state planes to express four dimensions circuit, transient dynamics, soft switching condition and design rule are presented. Subsequent experiment is performed for Brushless DC Motor (BLDCM), and their results confirm validity of analysis and design rule presented.