A PSPWM with variable frequency control for a two-output three-level series resonant inverter

This research paper presents a two-output three-level series resonant inverter by using phase-shifted pulse width modulation with a variable frequency control technique. In order to achieve the boundary condition of operation under ZVS for all switches, this paper will analyze this condition which depends on operating frequency and phase-shifted angle between the gate signals of the outer switches and the inner switches. In addition, the proposed circuit was designed, built and tested. The test has two cases which include fixed frequency control and variable control method. From the experiment, the fixed frequency control cannot obtain the ZVS condition of switches for all phase-shifted angle values. On the other hand, the variable frequency control can maintain the ZVS condition for all phase-shifted angle values that is in line with the proposed concept.