Research On Parallel Transmission Method Of Signal And Power In Bidirectional ICPT System Based On D-LCC

With the development of wireless power transmission technology,the two-way inductively coupled power transfer(ICPT)system has gradually shown its unique advantages in applications.In the non-contact traction power supply of rail transit,the grid provides electric energy to the train in the traction state,and the train in the braking state feeds back the electric energy to the traction grid,which can realize the bidirectional flow of electric energy between the "source" and the "load".The ICPT system avoids the problems of pantograph-to-net coupling,negative sequence,and excessive equivalence in the traditional contact power supply mode.It has the characteristics of flexible power supply,safe and reliable,and low maintenance cost,and is suitable for short-distance high-power transmission.It mainly used in rail transit traction power supply,industrial production,non-contact charging of electric vehicles and other occasions.There is a demand for signal interaction in the practical application of the bidirectional ICPT system.For example,parallel transmission of signals and electric energy in rail transit can assist trains to run efficiently and reliably,and signal interaction can provide trains with information such as control and feedback.Therefore,it has important practical significance to study the parallel transmission method of signal and electric energy in the bidirectional ICPT system.This paper focuses on the characteristics analysis of the signal and power parallel transmission method of the D-LCC type bidirectional ICPT system,the parameter design of the signal coupling coil,and the verification of the phase shift control of the bidirectional ICPT system based on the parallel transmission of signal and power.First,by comparing and analyzing the transmission characteristics of the typical resonance compensation network,it is determined that the D-LCC resonance compensation network is used as the main circuit structure of the bidirectional ICPT system.The series injection FSK signal modulation and demodulation method is used to give the bidirectional ICPT system signal and power.The circuit structure of the parallel transmission method;Further in terms of characteristic analysis,the transmission characteristics of the system power transmission circuit are analyzed,and the system power transmission circuit and the system signal transmission circuit are respectively modeled,and the state space model and the AC impedance method are used to analyze the mutual interference problem between signal and electric energy,the feasibility of the method is verified by analyzing the frequency domain response characteristics;the parameter design of the signal coupling coil,considering that the inductance of the signal coupling coil in the series injection structure has an impact on the power transmission circuit and the signal transmission circuit,aiming to improve the efficiency of power transmission,the signal coupling coil parameters are designed from the perspective of signal transmission quality,the design range of the signal coupling coil inductance is selected based on the superposition principle,and the AC impedance method is used to analyze the signal transmission rate,channel bandwidth,and signal-to-noise ratio of signal transmission.The relationship between the signal coupling coil inductance and the optimal value point are obtained,and the transmission efficiency and frequency response are compared for simulation verification.Finally,in order to verify the validity and correctness of the given signal and power parallel transmission method and the designed signal coupling coil inductance,a D-LCC type bidirectional ICPT system simulation model is built based on the MATLAB/Simulink platform.The signal transmission circuit is used to transmit the control signal to realize the phase shift control of the bidirectional ICPT system.Through the theoretical analysis of the D-LCC type bidirectional ICPT system signal and electric energy parallel transmission method,it is found that the mutual interference between the signal and electric energy in parallel transmission is small.The bode plot and signal error rate of the analysis system show that the signal transmission does not cause obvious interference to the power transmission efficiency of the main circuit,and the high accuracy of signal interactive transmission is realized.By giving the signal coupling coil inductance design method,the system power transmission efficiency and stability are effectively improved.