The Research On The High Power Bi-directional Electric Vehicle Charging Power Supply

With the gradually reduce of the non-renewable energy and haze weather frequent attacks, the advantages of high efficiency, energy saving, environmental protection of electric vehicles has attracted widespread attention. Electric vehicle charging station is the energy supply center of electric vehicle, excellent electric vehicle charging infrastructure is the commercial premise and foundation of electric vehicle. In the charging process of the traditional electric vehicle charging device will produce a large number of non-linear, impact load and they will cause the deterioration of power quality, influence the normal operation of the electronic equipment. Aiming at the shortcomings of the traditional electric vehicle charging device, this paper studies a kind of high power, bi-directional, low harmonic of electric vehicle charging power supply. The exploration and research of high power bi-directional electric vehicle this article mainly consists of the following aspects:Firstly, this article introduces the technology of electric vehicle charging and charging power supply development present situation at home and abroad and summarizes the commonly used the current-sharing control technology at present and then analysis and contrast the traditional topological structure of electric vehicle charging power supply. Adopting two levels of structure of the traditional electric vehicle charging power supply, there is a high harmonic content, low power factor, the high current distortion rate in power grid side and large impact to power grid and so on. In this paper propose a two-stage type high-power bi-directional electric vehicle charging power supply topology structure, for the pre-stage the main circuit adopts three-phase efficiently PWM converter, post-stage circuit using isolation transformer with bi-directional full bridge DC/DC converter structure, after designing of main circuit in detail and the selection of the device, and research the control strategy of high-power bi-directional electric vehicle charging power supply and the corresponding mathematical model is established.Secendly, analysing the working principle of charging power supply. To realize the difference and rapid tracking control system, for the pre-stage converter adopt a composite deadbeat current tracking control method. To post-stage of the whole bridge DC/DC converter, a double closed-loop control strategy of voltage out loop and current inner loop is proposed, which can achieve the charging power supply high precision, low ripple output. To test and verify the feasibility of the proposed control method and built the simulation model. For charging stations multi-parallel current-sharing problem, this paper discusses a kind of automatic current-sharing control strategy based on virtual resistor, which can improve the output characteristic of the electric vehicle charging power supply and achieve the current-sharing control of multi-parallel charging power supplies.Thirdly, this article discusses the high-power bi-directional the electric vehicle charging power supply hardware and software design of the control system and finally set up the experimental prototype, and then carried on related experiments on the prototype, the experimental results show that the prototype performance parameters meet the requirements of electric vehicle charging technology, and in this paper, we study the high-power bi-directional electric vehicle charging power supply topology and control method is reasonable.For shortcomings of traditional electric vehicle charging power high harmonic and low efficiency,this paper studied the high-power bi-directional electric vehicle charging power supply with zero pollution, low ripple and high efficiency etc, and also can feedback to the grid when the peak of power, increase the efficiency of energy and power system stability.