Study On Control Technology Of Contactless Power Transfer System And Implementation

Contactless Power Transfer (CPT) technology is a new power transfer technology. It combines of modern power electronics technology, magnetic coupling technology and high-power high-frequency transform technology in virtue of modern control theory and method, transferring power contactlessly from stationary source to movable loads with space electromagnetism coupling. The technology overcomes disadvantages of traditional power transfer methods and develops rapidly both in theoretic and application because it is safe, reliable and agility.This paper based on National Natural Science Foundation"Research on key technology of efficient contactless power transfer system with multi-degree freedom". It deeply studies the circulating current problem of primary energy converter in of CPT system, the main circuit control technology and related issues.Firstly, it introduces the main circuit and control technology of CPT system at home and abroad, analyses the basic principles of the system, the structure and the control requirements of every parts, describes the necessity and advantages by using digital signal processor (DSP), establishes the framework of CPT control system based on DSP.The paper mainly investigates the control technology of DC/DC converter and the circulating current of parallel load resonant inverter. It builds the dynamic small-signal model of Buck converter, analyses its open-loop frequency characteristics, suggests using Fuzzy PID control method to control the system, designs the controller and simulates the model. The simulation results show that Fuzzy PID can better realize the rail current invariableness control. The stability, anti-interference ability and speed of dynamic response are improved. It also analyses the factors and hazards of circulating current in parallel resonant load inverter, as well as the working mechanism and the mathematical model of the inverter when the circulating current exist. It points out that the resonant frequency change and the switch-off time delay is the factor that result circulating current, suggests using frequency and phase adaptive regulation to inhibit circulating current, establish the simulation model of circulating current inhibition system. The simulation studies show that the method can inhibit g circulating current, so that the inverter can full works in soft-switching. It reduces the switching losses, improves the quality of output voltage and current waveform, and thus improves the reliability, stability, and transmission efficiency of the system.Finally, the design of the CPT control system based on DSP is introduced, including the selection of controller, the hardware circuit and software flow. The experimental study shows that the control system can better achieve the control goal of the CPT system.