Research On Constant Current And Constant Voltage Compensation Network For Single-tube Inverter Wireless Power Transmission

When a certain kinds of wireless power transfer(WPT)compensation network introduced to the full/half bridge inverter circuit,the mode switching between constant current output(CCO)and constant voltage output(CVO)can be realized.However,the two kinds of circuit topologies used 2 or 4 switches,increased the volume and cost of circuit,improved the complexity of control,and there may cause a short circuit on the arm of bridge.The two kinds of circuit are mainly used in medium and high-power applications.Single-switch LC inverter circuit has only one switch,the low cost,high reliability can be expected,and it is mainly used in low-power field.However,the relative CCO and CVO research in single-switch circuit to is quite rare.To solve this problem,in this paper,the LC-DSLCC compensation network and P-CLCL compensation network based on single-switch circuit is proposed.By switching the operation frequency,the mode switching between CCO and CVO can be realized,and the process of topology modeling,calculation of parameters,analysis of characteristics of these two kinds are detailed in this paper.In chapter 2,the Fourier decomposition is used to calculate the RMS value of equivalent input voltage source waveform in single-switch circuit,which lays a foundation for analysis and calculation the circuit parameters.For the ease of the analysis and calculation of parameters,the LC-DSLCC compensation network and P-CLCL compensation network are modeled by T network model respectively.And then,the frequency characteristics,high-order harmonic suppression ability,the sensitivity of parameters are analyzed to explore their working characteristics.Using the image drawn by Mathcad software,a method used to calculate the primary-side compensation capacitance in P-CLCL compensation network was also proposed creatively.In order to realize the requirement of reliable constant voltage charging for lithium battery,the reliability turn-off of PWM signal when finished the charging,over-current protection of circuit,and wireless communication between primary and secondary sides and so on.In chapter3,the auxiliary power supply,driving circuit,voltage detection circuit,current detection circuit,wireless communication circuit between primary and secondary sides,and the overcurrent/overvoltage detection circuit in the primary side are designed in detail.By adjusting the operation frequency and duty cycle of driving signal automatically,the output will be kept constant,meanwhile,the zero voltage switching(ZVS)can also be realized to complete the charging experiment of the lithium battery.In chapter 4,two kinds of compensation networks are simulated by Saber simulation software with variable load.The simulation results show that the two kinds of compensation topologies have excellent CCO and CVO characteristics,which confirms the correctness of the theoretical analysis and the calculation of parameters.Then,use the P-CLCL compensation network built the cutting load experiment platform and the lithium battery charging experiment platform respectively,to carry out the experimental verification.The open-loop cutting load experiment show that the circuit can keep excellent CCO and CVO characteristic although the load changing suddenly,proves the feasibility of the circuit.The closed-loop cutting load experiment and lithium battery charging experiment verify the correctness and rationality of the design of hardware circuit.The P-CLCL compensation network with the CCO and CVO characteristic proposed in this paper can be widely used in small and medium power battery charging.