三相隔离型AC-DC-DC电源自适应线性自抗扰控制方法及纹波抑制补偿策略

Adaptive Linear Active Disturbance Rejection Control Method and Ripple Suppression Compensation Strategy for Three-Phase Isolated AC-DC-DC Power Supply

三相隔离型AC-DC-DC电源因其具有功率密度大、电气隔离等优点,在工业上应用广泛。但在一些负荷频繁投切的特殊应用场景下,如电泳、电镀等,基于传统PI控制的电源存在输出电压响应速度慢及纹波大的问题。为了提升电源的输出电压响应速度,该文在分析线性自抗扰控制中关键带宽参数与输出量之间关系的基础上,提出一种控制器带宽参数自适应调节的线性自抗扰控制(A-LADRC)方法以实现输出电压在负荷突变下的快速调节。而针对系统前级不控整流环节中电压六脉动分量对后级系统带来的输出电压纹波增大问题,设计一种根据系统输出电压反馈值,自适应调整变换器占空比补偿量的控制策略,以实现减小电压纹波的目的。最后通过一台400 V/50 A的实验样机对所提方法进行了验证,结果表明所提方法能够有效提升系统输出电压响应速度并减小电压纹波,具有较好的实际工程应用价值.

Three-phase isolated AC-DC-DC power supplies are widely used in industry due to their advantages of high power density and electrical isolation.However,in some particular application scenarios with frequent load switching,such as electrophoresis and electroplating,since the core isolated DC-DC converter is a typical nonlinear system,the power supply based on the traditional PI linear control method has slow output voltage response speed and large ripple,and cannot cope with the voltage sag or swell caused by the sudden change of load,especially for voltage-sensitive DC loads.Therefore,improving the output voltage response speed and reducing the ripple from the control level is urgent.This paper analyzes the relationship between the key bandwidth parameters and output quantities in the linear active disturbance rejection control based on traditional linear active disturbance rejection control research.An Adaptive linear active disturbance rejection control(A-LADRC)method with adaptive adjustment of the controller bandwidth parameters is proposed.The proposed control method can collect the current value supplied to the load terminal by the system in real-time,and select it according to the designed controller bandwidth.According to the rules,the bandwidth parameters of the controller are adjusted online to realize the rapid adjustment of the output voltage under the sudden load change.In view of the increase of the output voltage ripple caused by the voltage six-pulse component in the uncontrolled rectification of the front stage of the AC-DC-DC research system,the six-fold frequency pulsation of the power supply is analyzed by formula.Then a duty cycle compensation control(DCCC)strategy is designed to adaptively adjust the duty cycle compensation of the converter according to the feedback value of the system output voltage.This method can provide the compensation amount of the converter duty cycle according to the detected output voltage deviation,assisting A-LADRC in fine-tuning the system output voltage to reduce voltage ripple.Finally,the proposed method is verified by a 400 V/50 A experimental prototype.The experiments compare and verify the traditional PI control,linear active disturbance rejection control,and the A-LADRC with the duty cycle compensation control proposed in this paper.The experimental results show that among the output voltages at system startup under the same control parameters,the proposed A-LADRC control takes the least time to reach stability,and the time is 0.03 s,which is about 80%less than that of the PI control,and overshoot is significantly reduced.In the sudden load simulation experiment,the output voltage dropped from 200 V to 30 V under PI control.Under the control method proposed in this paper,the output voltage only suddenly dropped to 194 V,and the sag amplitude was reduced by about 96%compared with PI control.During PI control,the output voltage ripple fluctuation amplitude is 3.2 V.After using the control method proposed in this paper,the voltage ripple fluctuation amplitude is about 0.31 V,about 90%lower than that of PI control.The results show that the proposed method can effectively improve the response speed of the system output voltage,reduce the voltage ripple,and solve the problems caused by the AC-DC-DC power supply in particular application scenarios from the control level.