| Wireless Power Transfer(WPT)technology has been applied in more and more fields because of its convenience,flexibility,security and efficiency.In the application of WPT system,fast and reliable information interaction between the primary and secondary side is often required,such as tracking of optimal efficiency,feedback control of output power,upload of load’s status information,etc.parallel transmission of power/signal technology has become an important part of information interaction in WPT system.At present,there are four main ways to realize signal transmission in WPT system: near-field communication technology,signal coil transmission,power modulation and independent carrier modulation.Near-field communication technology has pairing delay,signal coil has poor anti-offset performance of transmission,and power modulation can hardly avoid power fluctuation.Therefore,independent carrier modulation with small delay,high anti-offset capability and no energy fluctuation is gaining attention.Independent carrier modulation is also known as Parallel Transmission of Power and Signal(PTPS)technology,but PTPS system with bidirectional signal transmission(hereinafter referred to as PTPS system with full-duplex mode)can realize both forward and backward signal transmission at the same time of power transmission,and has higher communication efficiency to meet the real-time information interaction between primary and secondary side.It is an important research content in the field of WPT at present.The transmission process of PTPS system includes not only power waves but also forward and backward signal carriers.As a result,the complex system circuit and various parameters restrict each other,which makes PTPS system face many key scientific and technological problems to be solved.First,the effect of adding signal transmission channels on power transmission needs to be considered,otherwise the resonance state of power transmission is destroyed and power transmission efficiency is low.Secondly,the signal transmission process is interfered by the power transmission,the signal demodulation is difficult,and even the communication may fail if the interference is serious.At the same time,the forward and backward signal carriers in full-duplex mode interfere with each other,further reducing the signal-to-noise ratio,which limits the data rate and makes it difficult to meet the actual communication requirements.In addition,because of the the circuit complexity of the PTPS system in full-duplex mode and the large number of parameters,it is difficult to optimize the transmission performance of the system in order to ensure the robustness of the system.These problems restrict the promotion and development of PTPS technology.Therefore,it is the key to realize a PTPS system with stable power transmission,high signal-to-noise ratio and full-duplex communication mode.In this paper,according to the requirements of power transmission and full-duplex signal transmission in WPT system,the power and signal transmission performance of PTPS system are studied,and on this basis,the topology and parameter optimization methods for full-duplex mode of PTPS system are mainly studied.This paper mainly carries out the following research work:To meet the requirements of full-duplex communication in static WPT system,a PTPS system based on the combination of double-sided LCC compensation topology and blocking network is presented.Based on the double-sided LCC compensation topology,a mathematical model of power transmission channel is established,and the resonance relationship considering the impedance effect of blocking network is deduced.A new type of PTPS system is presented to solve the problem of power interference to signal and the interference between signal carriers.Based on the carrier separation method of blocking network and the impedance analysis of the signal transmission channel,the resonance relationship of the parameters of the signal transmission channel is deduced.In order to reduce the transmission performance of PTPS system under dynamic conditions,a power transmission channel PTPS system based on double-sided LCCL compensation and signal transmission channel based on dual notch circuit is presented.Based on the double-sided LCCL compensation topology,the resonance relationship of the power transmission channel is deduced,the frequency characteristics of the power branch are analyzed,and the power transmission topology to reduce the interference to the signal transmission is obtained.Based on the band-pass characteristics of dual notch circuit,a full-duplex mode parallel transmission system for PTPS system is presented,then the impedance characteristics of the signal transmission channel are analyzed,and the gain of forward and reverse signal transmission and interference gain are obtained.To meet the transmission requirements of PTPS system under dynamic conditions.To meet the requirement of high power application of PTPS system,a signal full-duplex transmission system based on dual-resonant circuit is proposed to solve the problem of signal-to-noise ratio limitation in high power PTPS system.Power transmission channel is based on double-sided LCCL compensation topology,which ensures stable transmission of primary side constant current and load constant current.Resonance point distribution and parameter resonance relationship of dual-resonant structure in signal transmission channel are analyzed.On the basis of this,the impedance characteristics of the signal transmission channel are deduced,and a full-duplex communication method to suppress the interference of the same side signal source is presented.To overcome the limitation of signal-to-noise ratio of PTPS system,a parameter optimization method to improve the signal-to-noise ratio of PTPS system is presented by using the high gain characteristics of dual resonance points in the dual-resonance structure and the band-pass characteristics of isolation transformer.The system has stable power transmission and high signal-to-noise ratio signal transmission.To solve the problem of multi-objective optimization of PTPS system,a design principle of PTPS system parameters for comprehensive performance goals is presented.To solve the problem that the transmission performance of PTPS system is affected by the parameters of coupling mechanism,a mathematical model of coupling mechanism considering the influence of proximity effect is established,and an optimal coil parameter design method based on inductance-resistance ratio is presented.To improve the comprehensive performance of PTPS system,based on the index of energy and signal transmission performance,a comprehensive performance function is established to measure the energy and signal transmission performance quality of PTPS system.Further,based on the multi-parameter optimization method,the Pareto optimal frontier and Pareto optimal solution set of the system are obtained.A parameter design principle to improve the comprehensive transmission performance of PTPS system is presented. |
