Low frequency PWM inverter using an independent resonant DC link

Low frequency PWM control of a quasi-resonant, voltage source inverter associated with a suitable high frequency resonant interface is proposed. One can thus consider using this structure for high-power GTO applications, where the target frequency is several kHz, without including high value reactive elements. Decoupling of the resonant interface and the inverter is proposed concerning both QRDCLI structure and control. This approach requires modelling of the assembly formed by the oscillating circuit, the power converter and the load. Theoretical analysis is validated by an experimental prototype based on digital control of the PWM quasi-resonant voltage inverter