Research On A New Type Of Super Sparse Matrix Converter With Improved Voltage Transfer Ratio

Since the advent of Matrix Converter(MC),it has attracted much attention from researchers because of its excellent input and output characteristics and adjustable power factor.However,due to the large number of switches,the commutation control is more complicated and other shortcomings make it difficult to promote.Ultra Sparse Matrix Converter(USMC)has great research value due to its small number of switches and simple commutation.However,its application is still limited by the voltage transfer ratio.Therefore,it is of great research significance to effectively improve the voltage transfer ratio of USMC.The research work of this paper is as follows.First of all,in view of the relatively low voltage transmission problem of the traditional USMC,a new USMC topology that can improve the voltage transmission ratio is proposed.The specific implementation method is to add a Boost circuit to the DC link of the traditional USMC,and by increasing the intermediate DC voltage of the USMC,thereby broadening the voltage transmission ratio range.Secondly,the mathematical models of the topological structure under the two modes of large signal and small signal were established respectively,the working principle of the boost circuit was explained,the circuit component parameters were optimized and the design of the circuit component parameters was deduced,and the voltage transmission ratio and the boost circuit accounted for the new USMC were derived.The relationship between space ratio.Then,aiming at the AC high-frequency ripple in the output voltage of the rectifier stage and the phase shift of the boost circuit,a voltage feedforward closed-loop control strategy is proposed.The combination of feedforward and closed loop is applied to the DC bus voltage control,and the influence of DC voltage fluctuation on the output voltage can be completely offset by the feedforward control amount.However,in the actual circuit,due to the phase between the input and output of the control object Therefore,the DC output voltage value will have greater fluctuations,so the addition of feedback control can effectively control it.By reducing the DC link voltage fluctuations,the output power quality of the new USMC is improved.When the output voltage frequency is 50Hz and the voltage transmission ratio is 1.0,compared to the DC open loop,the new USMC output line voltage distortion rate of the DC closed loop is reduced by 37.73%.Finally,build a new USMC simulation model in Matlab,design simulation parameters,and perform simulation verification under DC open loop and closed loop respectively.It shows that the new USMC under DC closed loop improves the voltage transmission ratio while significantly improving the quality of the output voltage waveform.This verifies the correctness and effectiveness of the new USMC topology under DC closed-loop control.