三相电压型PWM整流器模型预测直接功率控制

Model Predictive Direct Power Control for Three-Phase Voltage Source PWM Rectifiers

摘要:

通过对三相电压型PWM整流器传统直接功率控制(DPC)引起的开关频率不固定,网侧电流谐波分量高,系统调节时间长等问题的分析,提出一种电压型三相PWM整流器模型预测直接功率控制方法,应用模型预测理论构建目标函数并对目标函数进行求偏导,对下一个采样周期的有功功率和无功功率变化进行预测,将模型预测理论与二阶拉格朗日插值法相结合进行功率修正,实现了有功和无功功率的实际值与预测值的误差最小,并采用空间矢量脉宽调制(SVPWM)产生PWM信号驱动整流器功率开关,实现固定的开关频率；仿真结果表明,本方法具有良好的动态和稳态性能,系统对电感参数的变化不敏感,有效降低了交流测电流总谐波失真(THD),提高了交流侧功率因数。

Abstract:

With the analysis of the problems caused by the traditional direct power control for three-phase PWM rectifier, including the unfixed switching frequency, net side current harmonic component is high,and system settling time is long,a scheme on the model predictive direct power control for three-phase voltage source PWM rectifier is proposed in this paper. Constructing the objective function by using model predictive theory and calculating the partial derivative of the objective function, to predict the variations of active and reactive power in the next sampling period, which achieves the tracking control to the given power of next period. By using model predictive and the second order Langrange interpolation method to correct the power, which achieves the minimum error of active and reactive power between actual value and the predicted value. And using the PWM signal generated by Space Vector Pulse Width Modulation (SVPWM) to drive the power switch of rectifier, which makes the fixed switching frequency. The simulation results show that this scheme has better dynamic performance and stable performance; The system is not sensitive to the change of inductance parameters; it can reduce the Total Harmonic Distortion (THD) of AC-link current effectively and can improve the power factor of AC-link.