Variable Mode Hybrid Control Based on Half-bridge LLC Resonant Converter for Stabilize The Voltage

摘要

In this paper, studies the voltage stabilization scheme for new energy electric vehicle charging, pulse width modulation and pulse frequency modulation (PWM+PFM) variable mode hybrid control strategy based on half bridge LLC converter is proposed. According to the change of input voltage and load, different control methods are adopted to stabilize the output voltage. When the input voltage and load variations is small, pulse frequency modulation (PFM) control is adopted. If the frequency regulation exceeds a certain range due to the input voltage rise and load drop, it is converted to PWM+PFM hybrid control. The whole process has zero voltage switching (ZVS) characteristics and reduces the switching loss. There is no need to add auxiliary circuits, stable output of voltage can be realized. And build a 500w experimental prototype to verify the effectiveness of the control strategy.