Research Of Power Amplifier Based On Digital Control

With the rapid development of the vibration table industry,and the power amplifier as an important part of the vibration table,its performance will directly affect the reliability of the vibration table.In order to improve the integration and reliability of the power amplifier control system and meet the quality and capacity requirements of the power amplifier output waveform,this paper studies the digital power amplifier based on FPGA control with the 240 k VA power amplifier project as the background,and put forward a method to improve the performance of the power amplifier and the device was developed.Firstly,the design of power amplifier module is carried out.In order to meet the requirements of large capacity of power amplifier,this paper adopts modular design,and the internal parallel structure of inverter unit is adopted in the module.The first,according to the technical requirements of the project,the main circuit and filter circuit of the inverter unit are designed.The second,the range of modulation frequency is 200 Hz ? 3k Hz,and 25 k Hz is chosen as switch frequency.In order to improve the quality of output electric energy and reduce harmonics,the carrier phase shift technology is adopted.The equivalent switching frequency is increased by 6 times,namely,150 k Hz,which reduces the module volume and improves the power density.The third,the Matlab/Simulink software was used to build the model of the main circuit.The simulation results verified the rationality of the design of the main circuit,and proved that the carrier phase shift control strategy could improve the quality of the output waveform,and the waveform THD value was obviously reduced.Then the control method design,the system adopts double closed-loop control strategy,focuses on the voltage outer loop design,researches and designs the improved incremental PID algorithm,and uses the Matlab/Simulink software to carry out simulation verification.The simulation results prove that the double closed-loop control can improve the system.Finally,the controller hardware and software design based on FPGA control is carried out.The hardware part includes the design of system controller and module controller hardware,PCB drawing and experimental verification.The software part is mainly for algorithm research design and implementation using Quartus software,including CPS-SPWM wave design,improved incremental PID algorithm design and temperature protection algorithm design,and simulation verification.The simulation results verify the rationality of the design.Based on the results of the above research and analysis,this paper completes the development and development of the control device,and assists the cooperation unit to carry out the development of the main circuit device,and finally carry out the corresponding experimental test.The experimental results show that with the carrier phase shifting technology,the switching frequency of the output of the inverter unit is increased by 6 times,and the system block can reach 3 k Hz.After adopting the double closed-loop control strategy,the output waveform has a good sinusoidal and is analyzed by the analyzer.The THD is less than 2%,which meets the requirements,and the output waveform tracking capability is significantly improved.