| Wireless power transfer technology,with the advantage of no connection and overcoming the limitations of traditional wired transmission mode,has been concerned by all walks of life.However,WPT technology still has some problems,such as low transmission efficiency,charging load can not move at will,and there are limitations in the use process.In this paper,the constant voltage output control method of radio energy transmission system based on the combination of optimal switching control and fuzzy PID control when the magnetic coupling coefficient changes is proposed.Further,the transmission efficiency and output power model of magnetic coupling resonant radio energy transmission system based on adaptive particle swarm optimization algorithm considering the internal resistance loss of the system are proposed.The main work includes the following points.Firstly,the model of radio energy transmission system is studied and analyzed.By equating the four basic compensation networks of magnetic coupling resonance radio energy transmission into T-type and π-type equivalent circuits,the relationship between the corresponding output voltage and current and the input voltage and current is deduced.Further,the SS topology of constant voltage input constant voltage output is selected as the compensation network of the system.Through the derivation of the circuit equation,the condition of constant output voltage while keeping the system running efficiently is obtained.It is proved that for the system without external control means,when the coupling coefficient between the primary coil and the secondary coil changes,the system can not maintain a constant output voltage and be in an efficient working state.Secondly,aiming at the change of coupling coefficient between primary coil and secondary coil,a hybrid control method combining optimal switching control and fuzzy PID control is proposed.The of the two control methods are analyzed respectively,and the controller is designed by using the rapidity of the optimal switching control and the characteristics of on-line optimization of PID parameters of fuzzy PID control.The simulation circuit is built through Simulink simulation software to compare its control effect,which proves the rapidity and accuracy of the hybrid control method.Finally,the actual circuit experiment shows that the hybrid control method can quickly change the working state of the system.In the over coupling region,the system realizes the constant output voltage and maintains an efficient working state.Thirdly,considering the internal resistance loss of the system,an efficiency model of magnetic resonance radio energy transmission system based on adaptive particle swarm optimization algorithm is proposed.In view of the phenomenon that the transmission efficiency of magnetic resonance radio energy transmission system increases first and then decreases with the increase of system voltage level and output power,taking the input voltage of DC chopper module as the decision variable,a function with output power and transmission efficiency as the objective is constructed,which is transformed into a single objective problem and solved by adaptive particle swarm optimization algorithm,which provides a control index for the system considering internal resistance.By comparing the simulation results with the calculation results,it is proved that the proposed system efficiency model considering internal resistance is reasonable. |
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