三相PWM整流器预测直接功率控制

Predictive Direct Power Control of Three-phase Pulse Width Modulation Rectifiers

针对三相PWM(pulse width modulation)整流器预测直接功率控制(predictive direct power control,PDPC)策略中,数字处理过程存在的延迟问题,设计两步预测方法消除延迟,并设计反馈校正环节对传统PDPC策略中参考功率不准确的问题进行修正,消除实际功率与参考功率之间存在的偏差.另外,在三相PWM整流器中,网压传感器使整个系统变得更复杂且耗费成本,因此采用改进型二阶广义积分器(second-order generalized integrator,SOGI)产生同频率的正交信号估算电网电压,并将基于改进型SOGI的无网压传感器算法应用于优化后的PDPC策略中.在仿真平台对所提方法进行仿真,结果表明所提方法消除了功率跟踪偏差,准确估算了电网电压.通过对比传统与优化后的PDPC策略仿真结果,验证了所提方法的有效性.

To solve the delay problems in the digital processing of the three-phase pulse width modulation(PWM)rectifier predictive direct power control(PDPC)strategy,we design a two-step prediction method to eliminate the delay and a feedback correction link to correct the inaccurate reference power in the traditional PDPC strategy,so as to eliminate the deviation between the actual power and reference power.In the three-phase PWM rectifier,a grid voltage sensor makes the whole system complex and costly.Therefore,we use an improved secondorder generalized integrator(SOGI)to generate orthogonal signals of the same frequency and to estimate the grid voltage.Then,we apply a grid voltage sensor-free algorithm based on the improved SOGI to the optimized PDPC strategy.The proposed method is simulated on the simulation platform.Simulation results show that the proposed method can eliminate power tracking deviation and accurately estimate the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results of the traditional and optimized PDPC strategies.