Research On Control Method Of Multi-source Converter

The development of electric vehicles has put forward higher requirements on the performance of energy storage systems.The traditional lithium-ion battery has a low power density and cannot meet the snowballs of electric vehicles.The hybrid energy storage system based on the multi-source converter can effectively improve the efficiency,energy density and power density of the electric vehicle power system,and can also greatly reduce the system volume and weight.Based on the working principle of the multi-source converter,this paper studies its control method: a new modulation method based on vector coordinates is proposed;the multi-source conversion is optimized and studied with the goal of reducing the peak power of the battery and controlling the super capacitor SOC Control method of energy storage system.The innovations and main research results of this article are as follows:First,this thesis analyzes the working principle of the multi-source converter,and proposes eight working modes for the energy flow path of the multi-source converter with different space voltage vectors.In order to determine the actual topology of the multi-source converter,the loss of power devices with different topologies is modeled and analyzed,and the influence of the unbalanced DC side of the multi-source converter on the space voltage vector was analyzed.A space suitable for the multi-source converter is proposed.Secondly,in order to realize the control of the multi-source converter system,this paper has carried out specific research on the multi-source converter power coordination control method,system capacity configuration method and energy storage element SOC control.Establish a multi-source converter mathematical,study the impact of different vector groups on the output power of the energy storage element to achieve coordinated control of the converter power,and improve the DC of the multi-source converter by analyzing the effect of modulation ratio and imbalance on the coordination performance The range of side power can be coordinated.Combined with the performance index of the multi-source converter system of electric vehicles,the system capacity and power characteristics are calculated,and the capacity allocation method of HESS and the super capacitor SOC control strategy are optimized.The control method was simulated and verified on the constructed multi-source converter system model.Finally,based on theoretical analysis,a multi-source converter 3k W experimental platform was designed.The multi-source converter modulation method,power coordination performance and power frequency division control strategy were experimentally verified,and the performance of the control strategy was analyzed.