Bilateral Coordinated Constant Voltage Control Of Variable Load Magnetic Resonance Wireless Power Transmission

Wireless power transfer(WPT)technology has been the focus of research in the fields of new energy and power electronics in recent years.Compared with traditional technology,magnetic resonance wireless power transfer has great advantages in security,transmission distance,transmission efficiency and load power,which is the main research direction of wireless power transfer technology at present.In this paper,the constant voltage output control of a variable load magnetic resonance wireless power transmission system is realized based on a bilateral cooperative control strategy.The main work of this paper includes the following points.First,by analyzing T-type and ?-type equivalent circuits,the input and output models of four basic topological structures of magnetic resonance wireless power transmission systems are studied,and select the constant voltage input-constant voltage output topology as the compensation network of the system.Using the theory of mutual inductance circuit to model the wireless power transfer system circuit,the influencing factors of system output voltage,load power and transmission efficiency are analyzed.It is proved that the system working at the natural resonance frequency cannot maintain a constant output voltage and higher load power when the coupling conditions between the coils change,and it cannot meet the actual application requirements.Second,based on the combination of Bang-Bang control and fuzzy PID control,an automatic frequency tuning controller is designed at the transmitter of the system,which makes the system work frequency automatically track the resonance frequency and keep the output voltage constant when the coupling conditions of the constant load system change.Compared with the traditional control method,the simulation experiment shows that the control method in this paper can adjust the working frequency of the system to the resonance frequency quickly and accurately,ensure the constant voltage output of the constant load system within the working range of the system,and maintain the maximum load power and transmission efficiency.Third,in view of the influence of the load resistance of the variable load WPT system on the system output voltage and resonance frequency,a constant voltage output controller is designed based on the sliding mode control method at the receiving end of the system,which cooperates with the automatic tuning controller at the transmitting end to ensure the constant output voltage of the variable load system.For the chattering problem of sliding mode control,an improved exponential reaching law is designed,which can not only eliminate chattering problem,but also has faster reaching speed than the traditional reaching law.Finally,it is verified by system simulation experiment that under the bilateral cooperative control of the controller at the transmitter and the receiver,when the coupling condition between the coils and load resistance value of system changes,the constant voltage output control of the magnetic resonance wireless power transfer system can be realized.