Research On Fractional Order Control Strategy Of Boost Converter

DC-DC converter is an important power electronic device,which has gradually been widely used in various fields such as electric vehicles,industrial instruments,military and so on.At the same time,its performance has been put forward higher requirements.The system output can’t meet the higher performance requirements because of the influence of the variation in load parameter,internal circuit parameter with time and input voltage under the complex and changeable working environment.And the control strategy is more essential for DC-DC converter to achieve the optimal output performance.Therefore,the exploration of DC-DC converter control methods has become an important aspect of the research in the field of power electronics technology,which with better performance in dynamic,static and anti-interference ability.At present,people have proposed many integer-order control methods for the control problems of DC-DC converter,such as PID control,sliding mode control,adaptive control,fuzzy control,etc.Most of them adopt voltage single closed-loop control structure.To a certain degree,these methods can improve the output performance of the converter,but each method has its own advantages and disadvantages.In recent years,people have found that fractional order control can obtain better system control performance and robustness than integer order control.At the same time,active disturbance control technology has been gradually paid attention and application in the field of control engineering because it has no dependence on the controlled object model,strong anti-interference ability,etc.Therefore,in view of the control advantages of fractional order control and active disturbance rejection control,this paper takes Boost converter as the research object,and proposes the double closedloop fractional order PI control method and fractional order active disturbance rejection control method of Boost converter.1.Double closed-loop fractional order PI control method of Boost converterIn order to improve the control performance and anti-interference ability of the boost converter output voltage,this paper proposes a double closed-loop control method with fractional-order proportional integral(PI)controller for both the voltage loop and the current loop.Based on the established mathematical model of the double closed-loop fractional order PI control system,combined with the control system frequency domain design theory,the fractional order PI controller parameters of the current loop and the voltage loop are designed.The stability and robustness of the controlled system are analyzed by the Bode diagram.The simulation results of double closed-loop fractional order PI control of Boost converter show that even under the conditions with variation in power voltage,load and expected output voltage,compared with double closed-loop integer order PI and voltage loop fractional order PI and current loop integer order PI in a control situation,this method can achieve better output voltage performance and control robustness.2.Fractional order active disturbance rejection control method of Boost converterIn view of the advantages of fractional order control and auto disturbance rejection control,the research proposes a compound control method with fractional order active disturbance objection control for Boost converter.On the basic of Boost converter mathematical model,the integer order active disturbance objection controller of current loop is designed by bandwidth and the parameters of fractional order PI controller for the voltage loop are designed under the frequency domain.The study analyzes the stability and robustness of system by the Bode diagram.The simulation results show that the fractional order active disturbance control method can quickly track the desired output voltage with variation in input power voltage,load and internal parameters.It can achieve better performance about fast response and anti-interference ability.The research results provide a useful theoretical method reference for Boost converter to explore the high-performance control strategy and improve voltage output performance and anti-interference ability of the converter.