一种改进的三相PWM整流器模型预测控制方法研究

Improved model predictive direct power control for three-phase PWM rectifier

针对传统的三相两电平PWM整流器模型预测直接功率控制(MPDPC)可选择的开关矢量有限,需要较高的采样频率才能满意的控制效果,从而带来较大计算量等问题,在变换器多矢量控制方法基础上,提出一种改进的三相PWM整流器模型预测直接功率控制方法。该方法在一个开关控制周期内使用一个非零矢量和零矢量组合替代传统方法的单矢量,并推导了占空比计算公式,提出一种简单计算的方法来计算非零矢量和零矢量的作用时间。相比于传统的单矢量枚举MPDPC,该方法具有计算简洁、鲁棒性强和受整流器电感、电阻参数影响小等优点。仿真和实验结果表明,在相同的开关频率情况下,所提出的改进的MPDPC可以获得与传统MPDPC相似的动态响应,并具有更低的功率脉动和更低的电流谐波含量。

For the drawbacks of traditional model predictive direct power control in three-phase two-level pulse width modulation(PWM)rectifier such as limited number of voltage vectors,and higher sampling frequency.To achieve satisfactory performance,which brings a large amount of computation,an improved model predictive direct power control(MPDPC)for a three-phase PWM rectifier was proposed.In the proposed method,an active voltage vector and a null voltage vectors are applied to replace the single vector of the traditional methodduring a control period.The duty cycles of active vector was determined by a simple calculation.Compared with the traditional MPDPC,the method has the advantages of simple calculation,strong robustness,and no dependence on rectifier parameters such as inductance and resistance.Simulation and experimental results show that the dynamic response of the proposed MPDPC is similar to that of the traditional MPDPC,and has significant power ripple reduction and lower harmonic distortion at the same switching frequency.