Research On Current Sourced Bi-directional Inductively Coupled Power Transfer System

Inductively coupled power transfer(ICPT)technology is mainly based on the law of electromagnetic induction,transferring power without direct electrical contact.So,it's very safe,convenient,flexible and reliable.In recent years,a lot of researchers and engineers have paid attention to ICPT technology and researched it.Bi-directional ICPT technology has wide application field and good practical value.For example,if electrical equipment can feedback power to the gird,it will be helpful to realize peak shaving and valley filling,so as to solve the problem of grid's power climbing.What's more,if electric vehicles can feedback power by regenerative braking,it can improve the efficiency.When power can be fed back wirelessly,the four quadrant operation of motors can be realized.In addition,the wirelessly bi-directional flow of power is a key point of constructing wireless power transfer networks.The existing literature mainly researches the main circuit topology,compensation network,power regulation,signal transmission and so on.However,only a few researchers put their eyes on bi-directional power transfer.Moreover,the literature pays more attention to realization of the function,but they haven't considered security,reliability and simplicity of the system.This paper focuses on current sourced bi-directional ICPT system,tries to solve the problems of circuit security,control reliability,realization complexity existing in present bi-directional ICPT systems.The purpose of this paper is to propose a kind of securer,more reliable and simpler circuit topology and control method.The research of this paper is helpful to achieve the practical application of bi-directional ICPT technology.In order to improve the security of the circuit,this paper takes use of current sourced inverter,and proposes a compensation method who takes CLCS(CapacitorInductor-Capacitor-Series)network at primary side,and LCL(Inductor-Capacitor-Inductor)network at secondary side.This method can keep the system safe even the driving signal is wrong,the load is gone,or the system is shut down.Besides,power transfer ability of the proposed compensation method is better than the existing methods'.To improve the reliability,this paper proposes a control method who takes bi-directional DC/DC to control the current on primary side,and no-bridge voltage regulator to control the voltage(or current)on secondary side.No-bridge voltage regulator regulates the output voltage(or current)by trigging the switching devices of the controllable rectifier bridge on secondary side.Not only it takes no additional circuit,but also makes full use of the existing components in the system.Taking control methods at both primary and secondary sides makes the system much more reliable.In order to make bi-directional ICPT system simple and easy to realize,this paper takes control methods at primary and secondary sides respectively.The signals of coil current at primary side and output voltage(or current)at secondary side are sent to their MCUs respectively.Therefore,the system doesn't need additional wireless signal transmission.Besides,the two closed loops make the output of the system more accurate.On the basis of the above theoretical analysis,the simulation model and experimental platform are established.The results of simulation and experiment prove the feasibility and effectiveness of the proposed method.