基于单三相兼容PFC的过零点畸变抑制策略

Zero-crossing Distortion Suppression Strategy Based on Single/Three-phase Compatible PFC

单三相兼容功率因数校正(PFC)变换器应用广泛,具有效率高、稳定性好、兼容单相和三相电源等优点。但该拓扑在单相运行时,网侧输入电流在采用传统控制策略下的过零点畸变严重,影响着单三相兼容PFC变换器的稳态运行性能。此处首先分析了所采用的单三相兼容PFC变换器的拓扑结构,指出了变换器单相运行时电流过零点畸变的产生机理。这里采用延时补偿和采样电压幅值补偿策略,解决控制延时带来的过零点畸变问题。在此基础上,通过对过零点处高频开关管和工频开关管采取分时开关策略,解决过零点处开关逻辑混乱导致的过零点畸变问题。为验证理论分析的正确性,搭建了一台1 kW单三相兼容PFC变换器实验平台,测试结果表明,所提出的策略能够抑制电流的过零点畸变,提高单三相兼容PFC变换器的稳定性。

Single/three-phase compatible power factor correction(PFC)converters are widely used,with the advantages of high efficiency,good stability,and compatibility with single-phase and three-phase power supplies.However,when the topology operates in single-phase mode,the problem of zero-crossing distortion of the input current with traditional control strategies seriously affects the stable control performance of single/three-phase compatible PFC converters.Firstly,the circuit topology of the adopted single/three-phase compatible PFC converter is analyzed,the mechanism of current zero-crossing distortion during the single-phase operation mode is presented.Adopting time delay compensation and sampling voltage amplitude compensation strategies to solve the problem of zero-crossing distortion caused by delay.On this basis,by adopting a time-sharing switching strategy for high-frequency and power frequency switches at the zero-crossing point,the problem of zero-crossing distortion caused by chaotic switching logic at the zero-crossing point is solved.In order to verify the feasibility and effectiveness of this scheme,a 1 kW single/three-phase compatible PFC converters experimental platform is built.The experimental results show that the proposed strategy can suppress the zero-crossing distortion of the input current and improve the efficiency and stability of the single/three-phase compatible PFC converters.