Research On High Frequency Power Converters Applied In Microwave Wireless Power Transmitter

The technology of wireless power transmission has gotten more and more attention for the advantages of high mobile flexibility and strong environment adaptation.With the advantages of low transmission loss,long transmission distance and high transmission efficiency,microwave wireless power transmission has provide a new way to charge the aircrafts.The microwave wireless power transmission can be divided into two parts: the microwave transmitter and the receiver.The radiation power of the transmitter directly determines the maximum power received by the receiver and delivered to the load.Under this background,this thesis carries out a research on the high frequency power converters applied in the transmitter of the microwave wireless power transmission system.To increase the output power of the RF source,this thesis proposes a Push-Pull resonant inverter based on a single-ended Class Φ2 inverter.Compared with the single-ended Class Φ2 inverter,the proposed Push-Pull resonant inverter doubles the output power without increasing the voltage stress or current stress of the switching device.It also remove the DC component from the input voltage of the load network,simplifying the design of the load network.Firstly,the working principles of the singleended Class Φ2 inverter and the impacts of the resonant components are analyzed in detail.Then the parameter design process of single-ended Class Φ2 inverter is given with the methods of impedance analysis.Secondly,a suitable driving circuit is proposed for the proposed Push-Pull resonant inverter.The driving circuit has two stagger output,a trapezoidal voltage and a sinusoidal voltage,avoiding shoot-through problem.To decrease the output harmonics,obtain high efficiency of the retina,and realize the radiation direction control,this thesis proposes a linear-resonant hybrid converter.This converter is composing of a linear amplifier in parallel with a resonant inverter at the load end.The linear amplifier,adopting a voltage-controlled AB amplifier controls the output voltage to be in phase with the reference voltage,achieving phase control and a pure sinusoidal output voltage.And all the power is delivered by the resonant inverter,a single-ended Class Φ2 inverter,to attain a high efficiency.To achieve efficient parallel,a resonant driving circuit is given.This driving circuit all composed of passive elements imposes a suitable phase-shift and an attenuation on the output voltage,acquiring a proper driving voltage for the resonant inverter.And the power of the driving circuit is also delivered by the resonant inverter.A prototype of 24 V DC input and 20 W AC output Push-Pull resonant inverter and a prototype of 5W AC output linear-resonant hybrid converter both operating at an output frequency of approximately 100 MHz were built in the lab.The simulation and experimental results are both agree with the theoretical analysis,verifying the feasibility of the proposed converters and the correction of the design methods.