Comparative analysis of three starting methods for parallel resonant current source inverter

In this paper three starting methods for an inductive heating equipment are proposed and analyzed. Starting concerns energization and control sequence. The equipment is based on a parallel resonant inverter connected to a resonant tank (coil and susceptor in parallel with a capacitor) for inductive heating applications. The inverter consists of a current source single-phase H bridge, which operates at the resonant frequency of the tank. The inverter is fed by a current controlled buck DC-DC converter, connected to the output of a six pulses bridge diode rectifier. The paper details the proposed starting methods and experimental results obtained in a 15kW, 540V DC laboratory prototype are presented. The operating frequency of the DC-DC buck converter is 2kHz and a the load resonant frequency is around 4,3kHz.