A Single-Phase Current Source Induction Heater with Improved Efficiency and Package Size

This paper presents a modified Current Source Parallel Resonant Push-pull Inverter (CSPRPI) for single phase induction heating applications. One of the most important problems associated with current source parallel resonant inverter is to achieve ZVS in transient intervals. This paper shows that the CSPRPI with integral cycle control method has dynamic ZVS. According to this method, it is the Phase Locked Loop (PLL) circuit that tracks the switching frequency. The advantages of this technique are higher efficiency, small package size and low EMI in comparison with similar topologies. Additionally, the proposed modification results in low THD of ac-line current; measured as less than %2. To show the validity of the proposed method, a laboratory prototype is implemented with operating frequency of 80 kHz and output power of 400 W. The experimental results confirm the validity of the proposed single phase induction heating system.