三相电压型PWM整流器双开关表直接功率控制策略

首先,提出了一种直接功率控制改进策略,用以解决三相电压型脉冲宽度调制整流器采用传统直接功率控制时存在的扇区判断算法复杂和无功功率周期性波动问题。该改进策略设置2个开关表,对无功功率误差进行判断,并根据误差大小选择不同的开关表。然后,对所提出的扇区判断方法进行了分析,该方法避免了复杂的坐标变换和反正切函数运算;给出了2个开关表的选择原则,即分别以最大限度地降低开关损耗和提高无功功率响应速度为原则。最后,通过MATLAB/Simulink仿真与传统直接功率控制进行对比。仿真结果表明,该改进策略不仅取得了更低的交流侧电流谐波总畸变率,同时有功功率、无功功率到达稳态的时间也提前近38.5%。

A Double Switching Table Based Direct Power Control Strategy for Three-phase Voltage Source PWM Rectifiers

Firstly,an improved strategy of direct power control(DPC) is proposed to solve the complexity problem of sector determination and reactive power cyclical fluctuation problems under the traditional DPC strategy in three-phase voltage source pulse width modulation(PWM) rectifiers.The improved strategy adopts two switching tables and chooses the different ones in accordance with the reactive power errors.Then the new algorithm of sector determination is presented aiming at avoiding the complexities involved with coordinate transformation and arctangent function.Furthermore,the principle of selecting the switching tables is provided to reduce the switching losses and enhance the reactive power response speed.Finally,a simulation model is established under MATLAB/Simulink environment to compare with the results obtained from both the proposed and the traditional DPC strategies.The simulation results show that the proposed strategy has much lower total harmonic distortion(THD) rate at the AC side,meanwhile the response time for both active and reactive powers reaching the steady state is reduced by 38.5% as compared with the traditional approaches.