A Review: An Improved LLC Resonant Inverter for Induction Frequency Using Different Electrical Applications

In this paper, A simple power-control scheme for high frequency an LLC resonant inverter with asymmetrical control technique is proposed. The aim is to control the output power for high-temperature applications like steel melting, brazing, and hardening, where the load parameters and resonant frequency vary substantially throughout the system operation. The operating frequency is controlled using phase locked loop to track for the resonant frequency. The output power is controlled by adjusting the switch duty cycle. The LLC resonant tank is designed with a matching transformer in between the series inductor and paralleled LC resonant tank. The important advantage of the proposed topology is the short-circuit protection of the transformer and the induction coil. The validity of the proposed method is verified through computer simulation using MATLAB.