Analysis Of Boost DC-DC Converters Based On Digital PID Control

In recent years,the requirements of power supply performance have become higher and higher waking the analog power supplies unable to meet requirements in some application scenarios.With the rapid development of digital controllers,digital control technologies have been improved and matured.Therefore,the digital control of the power supply has received more and more attention and promoted the development of digital power supplies.Compared with analog controllers,the digital controllers have their inherent flexibility,ease of implementation of more complex algorithms,and allow designers to reprogram without the significant hardware modifications.In addition,the digital controller systems would not be affected by the parameter changes caused by temperature,humidity,device aging and other reasons.The research of the boost DC-DC converters based on digital PID control is focused on in this thesis.Based on the theory and methods of digital control related theory and digital control loops,the digital PID module,the digital peak voltage predictive module and the digital pulse width modulation module are researched and designed.By discretizing the analog PID,the digital PID control strategy,the algorithm idea and Verilog programming strategy are obtained and studied,which realizes the compensation of the loop and the stability of the system.The digital peak voltage predictive module is used to predict the peak value of the output voltage of the next cycle and calculated the duty cycle of this cycle to achieve advanced control.Therefore the loop delay is compensated.The output voltage waveform is smoother.Also,the stability of the Boost DC-DC converters is improved.The response speed of the system is accelerated,and the performance of the Boost DC-DC converters is improved.The digital pulse width modulation module adjusts the pulse drive signal through the duty cycle of the peak voltage predictive output to control the turn-on and turn-off of the switch in the power stage circuit.Then,the output voltage is adjusted.In this thesis,a digital pulse width modulation module is designed by the counter,and the pulse drive signal is generated by comparing the count value of the counter and the duty cycle value.The power stage circuit and the digital control loop of the digitally controlled Boost DC-DC converter designed in this thesis are modeled in MATLAB/ Simulink.Then thefeasibility of the design scheme and the stability of the system are proved.The Verilog program of the above digital modules are written in Vivado,which completes the functional simulation of the digital modules.By downloading the bitstream to the FPGA development board,the algorithm of the control loop is verified.Combined with the power stage circuit,a hardware test is performed to verify the feasibility of the digital control scheme in this thesis.