一种有源功率因数校正电流畸变抑制控制技术

摘要

为了减少风机驱动系统对电网造成的谐波污染，设计了一种带有功率因数校正功能的风机驱动器。在此项技术中，电流过零点畸变会影响功率因数校正的性能，为此提出了一种新的过零点畸变抑制方法并给出了理论证明和具体实现方式。采用占空比前馈补偿的数字控制，可以减小输入和输出电压对电感电流控制的干扰，从而使得输入电流能理想地跟踪输入电压。为了验证前馈补偿的效果，对输入阻抗进行分析进而说明了前馈补偿对电流相位超前的抑制作用。为得到准确的反馈电流，提出了一种电流采样方法，根据开关的占空比信息在一个P WM周期的两个不同时刻采样两次。文中所提出的方法可以有效抑制电流相位超前，减小电流过零点畸变，优化电流采样算法。仿真和实验结果都证明了所提出方法的正确性和有效性。%Single switch boost-type power factor correction (PFC) is applied to reducing power grid harmonic pollution in the fan motors control system.However,the current zero-crossing distortion will affect the PFC performance.To solve this problem,a new current zero-crossing distortion suppressing method and its concrete implementation are proposed.Digital control is adopted and duty ratio feedforward compensation is introduced to reduce the disturbance of input voltage and output voltage on the inductor current,forcing the input current to follow the input voltage changes;the input impedance is analyzed to show that duty ratio feedforward compensation can inhibit the current phase advance.A current sampling method is proposed to get the average current by sampling twice per PWM period.Simulation and experiment results show that the proposed method can inhibit current phase advance,eliminate input current harmonics,and achieve unity power factor correction,verifying the validity of the proposed method.