Research On Integrated Mechanism Of DC/DC Converter And Motor Drive System For New Energy Vehicles

As people pay more and more attention to non-renewable energy and environmental pollution problems,the automotive industry is mainly to study how to reduce fuel consumption and improve performance,so the birth of a new energy vehicles.For new energy vehicles,in this paper,the DC/DC converter and the motor drive integrated system are studied from the aspect of circuit.The DC/DC converter and integrated system of the neutral point motor drive are analyzed.The aim is to reduce the number of power switches and reduce the total system cost and volume;First,an Integrated System of DC/DC Converter with Neutral Point Motor Drive is proposed.With the use of neutral and zero sequence voltage(zero sequence current)of the motor,the motor and its drivers also function as DC/DC converters.The formula is deduced to get the theoretical basis and explain the working principle.The influence of fixed neutral point connection on high frequency ripple current is analyzed,and the expression of high frequency ripple current is obtained.According to the low-voltage DC source in a neutral point motor drive integrated system can be equivalent to a step-down DC/DC converter and for some low-voltage auxiliary circuits in new energy vehicles,a new type of step-down DC/DC converter for new energy vehicles is proposed,and its working principle and property are analyzed.Based on matlab,design simulation verification experiment.The experimental results show that the new converter has little switching stress and low output ripple current,which can improve the dynamic load performance of the system and reduce the system volume.It is suitable for new energy vehicles.Secondly,according to the new energy vehicle voltage level requirements,the proposed integrated system is designed,modeled,simulated and analyzed.Simulation results show that the integrated system can drive the motor to achieve 5kw output power and has a better output dynamic response and can achieve the energy flow between the two voltage sources,playing the role of DC/DC converter.For the motor drive part,compared with the typical DC / DC converter and the motor drive system,according to the speed,the magnetic chain closed-loop vector control,the proposed integrated system has a more stable output dynamic response.