Research On Power Amplifier Based On GaN Device And FPGA

Power amplifier depending on the power device works can be divided into linear power amplifier and digital power amplifier,the traditional linear power amplifier power devices work in the district,the distortion small but big loss efficiency is low,not suitable for application in high-power,digital power amplifier power devices working in switch area,low loss of high efficiency but low output precision,but with wide band gap power devices and the development of digital chips,digital power amplifier performance is improved.At present,the application of digital power amplifier in magnetic suspension bearing,photovoltaic power generation and other fields requires bidirectional current output,so it is of great significance to carry out the research of bidirectional digital power amplifier.Taking bidirectional digital power amplifier as the research object,this paper studies the topology,working principle,control method and hardware and software design of bidirectional power amplifier.The main research contents are as follows:First this paper introduces the structure and composition of the bidirectional power amplifier,the working principle of each part of the bidirectional power amplifier is studied,based on the use of Fourier series theory established the mathematical model of bidirectional power amplifier,get the closed-loop transfer function can be converted into standard second order system form,the damping ratio and natural frequency are expressed with the specific parameters,such as can intuitive see the influence of parameters on the system,and the scope of control parameters is deduced,on subsequent is of important guiding significance for the realization of the control method.And then studied the model predictive control based on bidirectional power amplifier,the prediction model,the objective function,delay compensation,feedback correction etc.Parts are introduced,and combined with the idea of integral compensation proposed an adaptive feedback correction methods,the selection of the feedback compensation coefficient setting,and set up in MATLAB/Simulink simulation model to verify the correctness of the proposed control method.Finally,the design of hardware and software of bidirectional power amplifier is studied,the driver circuit of hardware platform,sampling and conditioning circuit,overcurrent protection circuit and other parts are introduced in detail,and the matters needing attention in PCB design process are analyzed.According to the design process of FPGA,the control algorithm of digital power amplifier based on FPGA is realized by module.On this basis,the steady-state and dynamic performance of the designed bidirectional power amplifier are tested.The experimental results verify that the designed power amplifier has good following effect,small output current ripple,and good dynamic performance in the case of load mutation.