Research And Improvement Of Digital Current Hysteresis Control For Boost DC-DC Converters

In recent years,switching power supplies have developed rapidly and have been applied to more and more fields,which has led to an increasing demand for switching power supplies,and people are increasingly demanding switching power supplies.With the in-depth study of switching power supply control methods,more optimization methods and control strategies have been proposed.The current hysteresis control strategy studied in this paper has the advantages of fast response speed,high control precision,good robustness and simple control mode,and it has been widely used.The current hysteresis control Boost DC-DC converter has good performance in the steady state process,but the transient control process using the same control strategy will cause the transient recovery process to take too long.In order to solve the problem that the transient recovery process of Boost DC-DC converter is too long,the theoretical analysis of the transient process of load surge and load dump is carried out in detail,and the mathematical model is established according to the working process of circuit load jump.Based on the current hysteresis control strategy,a transient control strategy is proposed.The improved control strategy uses the current hysteresis steady-state control strategy when the Boost converter is in the steady state.If the load jumps,it is judged whether the output current is sudden increase or sudden drop according to the jump of the output load.If the load current suddenly increases,the current surge transient control strategy is used,the on-time time of the switch is prolonged,and the transient recovery time depends on the magnitude of the inductor current:if the load current suddenly drops,the current dip transient control strategy is used,the turn-off of the switch is prolonged,and the transient recovery time depends on the magnitude of the output voltage.According to the design requirements,the appropriate parameters are selected and verified in the Matlab/Simulink environment.It can be seen that the improved control strategy can effectively shorten the transient recovery process time and improve the load adjustment rate in the case of load hopping,and the simulation results are basically consistent with the theoretical calculation results.Using ARM-STM32F407ZGT6 as the control platform,the prototype was built and the hardware test was completed.The experimental results show that the improved control strategy can effectively shorten the recovery time of the load jump process.The transient recovery time of load current surge is shortened from 2ms to 210?s,and the transient recovery time of load current drop is shortened from 6ms to 342?s.At the same time,the load regulation rate is improved,and the dynamic characteristics of the converter are significantly improved.