Application Research On Active Disturbance Rejection Control Of DC/DC Converter

With the large-scale promotion and application of power electronic converters in various industries,users’ requirements for their dynamic performance are also increasing.When it comes to the classical frequency domain method,it generally only compensates for a certain operating point of the converter,which can have good performance in steady-state operation.However,the dynamic performance is poor under severe working conditions such as large-scale load steps,which makes improving the dynamic performance of the converter an important issue in academia and engineering.DC/DC converters transmit energy through semiconductor switching devices.Frequent switching of the devices makes the converter exhibit strong nonlinearity,which makes the model obtained inaccurate.Therefore,this paper applies Active Disturbance Rejection Control(ADRC),which can estimate the system’s external disturbance and the system’s internal model uncertainty in real time.It avoids the difficulty of obtaining the accurate mathematical model of the converter and enabling the converter to High dynamic performance to cope with sudden load changes.The main contents of this article are as follows:(1)The basic principle of ADRC is introduced,the principle of selecting its order when applying linear active disturbance rejection control(LADRC)in Buck converter is given,and its discrete equation is derived for common digital control applications.The transfer function of the converter system verifies that the LADRC can cope with the problems of inaccurate modeling and time-varying parameters of the converter.(2)For Buck converter,the PI controller is used as the voltage loop to compensate the Buck converter,and then the output voltage loop of the Buck converter is controlled by the LADRC based on the bandwidth method.The ADRC parameters of the bandwidth method are difficult to set.The particle swarm algorithm is used to optimize the LADRC parameters on the original basis.The Matlab/Simulink simulation is used to verify the effectiveness of the method.(3)Aiming at the master-slave current-sharing control strategy of parallel Buck converters,this paper proposes a cascade control strategy using inner-loop PI controller and outer-loop LADRC.In the end,this strategy can effectively enhance the load capacity of the converter and show good load sharing performance.(4)DSP is used to control the Buck converter.The selection of hardware parameters of the hardware platform and the DSP model-based automatic code generation method are introduced.Finally,the control strategy designed in this paper is verified by experiments.It can effectively control the controlled object.