Research On Bidirectional Inductive Power Transfer System

Bidirectional inductive power transfer technology has been widely applied in electric vehicles for its bidirectional power transfer.Based on bidirectional inductive power transfer system,the paper gives a detailed introduction of three resonance compensation topologies,which includes LCL circuit,SS circuit and LCC circuit.In addition,the paper focuses on the harmonic analysis and dead-zone effect of bidirectional LCL-IPT system.As to the system harmonics,a generalized mathematical model is built.The given equations of harmonic currents and harmonic power with 180° and 120° phase-shift control can be used to exactly analyze the harmonic characteristics and its effect.The simulation and experimental results demonstrate the validity of the theoretical harmonic analysis.As to the dead-zone effect,based on the investigation of the switching characteristics of full-bridge converter,the dead zone limitation for 180° phase-shift control is given to avoid dead zone effect.The dead zone effect based 120° phase-shift control on voltage,current,power and harmonic is investigated to obtain corresponding influence coefficients of dead zone,which quantifies dead zone effect accurately.Furthermore,the paper proposes dead zone compensation method to eliminate the dead-zone effect.Finally,the operating states of the system under the dead-zone effect are analyzed.Simulation and experimental results verify the effectiveness of the proposed compensation method.In order to realize high power transfer,the paper proposes a novel of bidirectional IPT system based modular multi-level converter(MMC),the corresponding control strategy and equalization of submodule capacitor voltage are given.The simulation has been conducted to verify the related analysis.The MMC topology,corresponding control strategy and equalization of submodule capacitor voltage operates at high frequency,and can be also used in other high frequency applications such as power electronic transformers,which is of certain research significance.