| Abstract |
This paper deals with a new quasi-resonant dc link inverter with only one additional switch connected between dc voltage source and resonant inductor. First, circuit states for given switching and load current states are analyzed and classified into one of three operating modes, i.e., free-wheeling, inverting, and rectifying mode, The operating principle of the proposed inverter at inverting mode is analyzed by using the analogy to the DC/DC buck ZCS-QRCs. This analysis shows that the stable oscillation of resonant link and the soft swïtching of both the added switch and the inverter are guaranteed by only appropriately controlling the inserted switch according to the circuit state. Compared with the known resonant dc link inverters with well controlled oscillation of resonant link, the proposed inverter is the simplest one from the viewpoint of power circuit. Based on the analysis a proper current control algorithm is suggested. Operating characteristics of the proposed inverter with about 50 (KHz) resonant frequency are verified through simulation and experiment. |
