Study On Three-phase Interlaced And Parallel High-voltage Boost Converter

Today,the problem of social environmental protection and energy crisis is becoming more and more serious,the sustainable development of the traditional automobile industry is facing severe challenges.Comparing with traditional cars,new energy vehicles can alleviate the consumption of petroleum energy in the automobile industry,achieve zero pollution,reduce the exhaust emissions of automobiles,improve the air pollution which caused by haze and other problems.In this context,new energy vehicles have become the focus of the automotive industry,countries are constantly investing in funds and the introduction of policies to support the development of the new energy vehicle industry,compared with foreign countries,China's new energy vehicle industry started late,but the development is relatively rapid.At present,new energy vehicles have been industrialized,but there are still many technical problems which should be solved.As an important part of the energy transmission between the battery and the driver of the new energy vehicle,the two-way DC/DC converter gives the energy of the battery to the motor(Boost transformation mode)when driving the operation condition,and the energy of the motor is fed back to the battery(Buck transformation mode)when braking conditions,so the converter needs to have the highest possible transfer efficiency and reliability.In addition,the design of the new energy vehicle using the high-voltage DC bus architecture has become a trend,and the voltage level of the two-way DC/DC converter needs to be improved.In this paper,the problem of Boost transformation in high-voltage two-way DC/DC converter is studied,the circuit structure and control strategy of Boost converter are designed based on the three-phase interlaced parallel technology,and the output voltage level of the Boost converter is improved,and the performance index of converter efficiency,life,dynamic response and reliability is improved.The main work of this article is divided into the following three parts:(1)This paper summarizes the research status of new energy vehicles at home and abroad,as well as the current situation of two-way DC/DC converter structure and control strategy,makes a comparative analysis of the working principle,application and advantages and disadvantages of several common topological structures,and finally uses three-phase interlaced parallel topology for high-power situations of new energy vehicles.(2)Small signal modeling of the whole converter system working process,the introduction of state relationship,the system transfer function,Boost converter control strategy using voltage outer ring and current independent inner ring design,analysis of the voltage ring and current ring PI control parameters,and analysis of the voltage ring and current ring PI compensation characteristics.In Simulink,the digital simulation model of the three-phase interlaced and parallel high-voltage Boost converter is constructed,the simulation is carried out for possible undervoltage,overload,disturbance and other conditions,and the simulation results show that the performance of the Boost converter meets the expected requirements,and the feasibility of the control strategy is verified.(3)The TMS320F28335 is selected as the control chip of the system to design the system hardware circuit,including voltage current sampling circuit,auxiliary power supply circuit and overcurrent protection circuit.Based on the voltage current dual closed-loop control strategy,the three-phase staggered parallel high-voltage Boost converter control software is designed,including the main program and soft start protection,ADC sampling,digital PI,PWM generation and interrupt protection and other sub-programs.Finally,an experimental platform was set up to simulate the actual operating conditions such as undervoltage,overload and output voltage changes that might occur in the converter,observed the voltage and current waveforms,analyzed the actual working performance of the three-phase staggered parallel high-voltage Boost converter,and verified the validity of the hardware and software design.