Research On Electric-field Coupled Power And Signal Parallel Transmission Technology Via A Shared Channel

Electric-field coupled power transfer(ECPT)technology transfers power wirelessly without direct electrical connections utilizing a high frequency electric-field as a medium,and refers to power electronics,resonant compensation,and control technologies.ECPT systems adopt metal plates as coupling interfaces,which make the systems have advantages of reduced size and weight of coupling interfaces,high design flexibility,low cost,low electromagnetic interference,and low eddy current in the metal barriers between and near the coupling interfaces.ECPT systems also have ability to transfer power across metal barriers.For most ECPT applications,a reliable signal transfer link between the primary side and the secondary side plays an essential role in a well-designed wireless power transfer(WPT)system.For example,the regulation of the output voltage,load detection,status monitoring of electrical vehicle's batteries,frequency tracking,and the synchronization between controllers are some of frequently-used functions of ECPT systems.Besides,in practical applications,communication between electric equipment and the power source is also generally required,such as the backward transfer of the thermal and battery information of drills and electrical vehicles.The signal transmission between two sides of ECPT systems is helpful to realize these engineering requirement and improve the practicability of ECPT technology.This paper proposes an electric-field coupled power and signal parallel transmission technology(ECPST)via a shared channel,which can realize signal transfer of an ECPT system without influence of the power transmission.The research work contains:This paper proposes an ECPST method based on the circuit network impedance isolation.In this part,mathematical models of power channel,signal channel and the power crosstalk are established for ECPST systems with functions of half-duplex and full-duplex signal transfer.For half-duplex ECPST systems,the effect of the signa branches parameters on the power and signal transfer performance is analyzed based on the proposed model.Then the parameters design method is given after the analysis.For full-duplex ECPST systems,problems of the ipsilateral signal crosstalk is modelled and the suppression method for this crosstalk signal is proposed.Similar with the half-duplex case,the relationship among the signal branches parameters and system performance is researched,and the parameter design method is given afterwards.The simulation model and the experimental prototype are constructed to verify the characteristics of power and signal transfer,power crosstalk isolation,and the ipsilateral signal crosstalk suppression.This paper proposes an ECPST method based on the inductors' frequency-domain impedance isolation to solve the problems of the effect of the circuit parameters on the performance of the power crosstalk isoation.This paper analyze the topology of the inductor's parasitic parameters and gives the equivalent circuit of the inductor element,based on which the frequency-domain impedance model of the inductor is established.The relationship between the maximum impedance frequencies(MIFs)and the size and winding number of the inductor is given.The relationship curves of the impedance and inductor parameters is also given when the MIFs of inductors is determined.Then the impedance design method which is only related to the operating frequency and the signal carrier frequency is proposed.The power transfer,signal transfer and the power crosstalk isolation performance and are verified based on the simulation model and the experimental setup.This paper proposes an ECPST method based on the square-wave modulation to solve the problems of the ECPST method based on the sinusoidal wave modulation and enhance the baud rate of the signal transmission.The mathematical models of the power channel and power crosstalk are established for both half-duplex and full-dulplex ECPST systems.The frequency-domain characteristic of the signal channel is analyzed,and the signal channel is simplified further according to its high-pass characteristics.Then the time-domain response of the output signal is calculated.Based on the system model and expressions of the output signal,the signal branches parameters deisgn method is given.Finally,the simulated and experimental results verify the signal transfer performances under low and high baud rate signal transfer conditions.This paper proposes a constrained multi-objective optimization method for general ECPST systems to find the globally optimal solution of the paremeters design.This method is given based on a double-sided LCL compensated ECPST system.The objective functions considering the power transfer,signal transfer and the power crosstalk are given to evaluate the transmission performance of ECPST systems.Then the constraints considering the reasonable region of the element parameters and the voltage-current limitation of the element are expressed.Then the non-dominated sorting genetic algorithm II(NSGA-II)is adopted to solve the optimization problem.In this algorithm,the random number generation,offspring population generation,and the crossover of the parent population are improved.The global optimal solutions in the Pareto front set are solved.The simulation and experimental prototype are established to verify the operating performance of the ECPST systems with the selected parameters.