Pickup Device Design Of The Wireless Power Supply System For Electric Vehicle

Currently, energy and environmental issues have become increasingly serious. Inthis case, because of electric vehicles(EV) having the advantages of low pollution, lowenergy consumption, low maintenance costs, there is a very good market prospect forthem. But electric vehicles in the market at present are mainly charging in a contactlessmethod. This charging method has the following disadvantages: easy to wear, easy toproduce sparks, difficult to maintain, not safe enough and not beautiful.The development of wireless power transfer technology is a developmentopportunity for electric vehicles. Inductively coupled power transfer (InductivelyCoupled Power Transfer, referred ICPT) technology is a direction of wireless powertransfer technology. It is safe, flexible, easy to maintain, and has strong environmentalaffinity due to its non-contact power transmission.There are two ways to introduce ICPT technology into power supply system ofEV. The first is charging battery in a wireless way, and the second is supplying powerdirectly to the motor without battery in a wireless way. This will eliminate the securityrisks when using a contactless charging method.This design is for a demo system of wireless power supply for EV, the demosystem is owned by our laboratory. The main research content is pickup technologydesign of the demo system.First, the paper analyzes the functional requirements of the demo system.According to the requirements, the paper analyzes the characteristics of the two kindsof pick-up end of the two resonant compensation networks of the pickup circuit, thecharacteristics of several basic DC-DC circuits, and every power control strategy. Asuitable compensation network, DC-DC conversion topology, and power controlstrategy are used in designing the system.Secondly, the paper calculates the pick-up device equivalently according to therequirements of wireless power supply system, and thus get the entire mutualinductance model of the power supply system. It mainly focuses on the analysis of therelationship between the mutual inductance and the efficiency, maximum transferpower of the coupling mechanism when the current is large. According to therelationship, some optimization analyses on the mutual inductance value are made forthe actual situation. Then suitable mutual inductance value is selected and robust model is built for the simulation.Thirdly, the paper analyzes the inrush current in rectifier circuit and the spike ofswitch tube in DC-DC circuit, and gives the solutions. PI control method is applied forvoltage control when supplying power to the charger while hysteresis control methodis applied for voltage control when supplying power to the motor. Then, the simulationmodel is built.Finally, the hardware circuit is designed for experiments based on the analysisand simulation results. The results show the effectiveness of the design for the demosystem.