Research On Energy Analysis And Its Control Strategy Design Of DC/DC Converters

DC/DC converters provide load with fast response,stable and reliable DC power to meet the increasingly wide application of power electronics.It is an effective way to improve the dynamic response,power density and operation efficiency of DC converters by studying the control technologies of DC converters.Although PI control strategy is still widely used in current applications,the inherent hysteresis characteristics and setting process of PI control strategy can not meet the needs for some special applications.Taking Buck converter as the research object,the energy change during the operation of the converter is analyzed,and the Energy Balance Control strategy is designed.According to the different time scales of the control strategy,the Single Cycle Energy Balance Control strategy suitable for dynamic process and steady-state operation,the Whole Process Energy Balance Control strategy used for improving dynamic performance are described respectively.Compared with PI control strategy,there is no need of parameter setting process,which greatly improves the efficiency of controller design.Compared with Time Optimal Control(TOC)strategy and other composite control strategies,there is no additional adjustment process caused by the change of control algorithm in the process of steady-state and dynamic process switching,and the optimal dynamic response characteristics are obtained.In view of the influence of energy loss and parameter nonlinearity on the control strategy and operation state of DC converters,the identification algorithm of internal loss equivalent resistance and parameter nonlinearity of DC/DC converters are designed from the perspective of energy analysis.The identification results are used to modify the Energy Balance Control strategy,which improves the adaptability of the proposed control algorithm to the changes of system model to a certain extent,and further improves the steady-state and dynamic performance of DC/DC converters.Based on the platform of Matlab/Simulink,the Energy Balance Control strategy and TOC strategy of Buck converter are built.The start-up process,the given voltage mutation process and the load mutation process are selected for simulation to verify the feasibility and superiority of the Energy Balance Control strategy.The identification and correction strategy is simulated to further improve the stability and reliability of the Energy Balance Control strategy.The experimental platform of Energy Balance Control strategy for Buck converter is built and experiments are carried out by hardware calculating circuits combining with TMS320-F28335 DSP.The experimental results further illustrate the superiority and practicability of Energy Balance Control strategy in the dynamic adjustment process,and the improvement of the existing energy control strategy in the steady-state performance is verified by the hardware calculation circuit.