Fast Vector Selection Model Predivtive Power Control For Reduced Matrix Converter Under Abnormal Grid Power Supply

As a isolated bidirectional AC-DC converter,reduced matrix converter(RMC)is used widely due to its advantages,such as fewer conversion stages,no large capacity components,bidirectional energy flow,and isolation between source and load.Finite set model predictive control has become a research hotspot,because its control principle is simple and no need for modulation process.However,traditional model predictive control methods has the problem of high computational complexity.The actual grid is affected by loads and exhibits abnormal operating conditions,such as unbalanced voltage with harmonics.The conventional control strategy cannot eliminate the problem of current distortion caused by this abnormal condition.Therefore,this article focuses on the research of RMC fast vector selection model predictive direct power control under abnormal power supply,with the aim of improving grid side performance with less computational complexity.Introduced the RMC model predictive direct power control and fast vector selection model predictive direct power control methods under normal grid power supply.Studied the improved fast vector selection model predictive direct power control method under abnormal power grid supply.Specifically,the extension power theory was introduced in response to the problem of grid side current distortion caused by unbalanced voltage in the power grid.By calculating the extension reactive power while as a constraint term,a fast vector selection model predict extension power control was used.In response to the problem of grid side current distortion caused by unbalanced grid voltage with harmonics,a cascaded delay signal cancellation method(CDSC)was introduced.By extracting the positive and negative sequence of grid voltage to eliminate harmonics and reconstructing a new grid voltage,the CDSC fast vector selection model predict extension power control is used to achieving the effect of reducing the harmonic content of grid side current and improving the quality of grid side current.An experimental prototype was built using DSP+CPLD as the controller architecture,and the control method studied was verified by experiment.The results showed that the model predictive direct power control achieved good input and output performance of RMC under normal power supply,and the calculation time of fast vector selection model predictive direct power control is shorter.Under abnormal grid power supply,an improved fast vector selection model predictive power control was constructed by introducing extension power theory and cascading delay signal cancellation method.This strategy reduces the harmonic content of grid side current caused by abnormal grid power supply effectively,improving current sine degree,and ensures grid side performance with less computational complexity.