改进的有源电力滤波器滞环电流控制策略

针对滞环电流控制开关频率不固定、频率范围大从而产生较大损耗的问题,以提高控制精度、减少开关损耗为目标,提出一种有源电力滤波器随机变环宽滞环电流跟踪控制方法。该方法针对电力系统负荷的特点,产生预置变环宽函数,能够较合理地给出滞环宽度,并引入随机函数,将开关频率范围拉宽,使电流频谱分布范围更宽,从而降低谐波畸变率,减少开关损耗。仿真及实验结果均证明了其可行性,可在保持总控制精度的同时有效降低总开关损耗,同时具有良好的补偿性能。

An Improved Hysteretic Current Method for Active Power Filter

In view of the considerable loss due to unstable switch frequency and wide frequency range in high harmonic distortion existing in traditional hysteresis control strategy for the three-phase voltage source pulse-width modulation (PWM) rectifier, an improved control algorithm for active power filter based on random variable bandwidth hysteretic current control is proposed. It allows significant reduction in the loss of switching produced by variable switching frequency and accurate compensation of harmonic currents. In order to modulate the accurate bandwidth of hysteresis current control, the approach based on the characteristics of load in the power system generated a bandwidth with random function able to widen the range of switching frequency, while effectively reducing the harmonic distortion rate and the switching loss. Simulation and test results of the shunt active power filter show the performance of the improved control strategy is feasible.