Research On Multi-Channel AC/DC Output Voltage Regulating Power Supply

With the rapid development of chip technology and power electronics technology,switching power supply has been applied everywhere,especially in some important scientific research sites and laboratories,which require power supply with multiple properties and voltage levels.However,most university laboratories or scientific research institutions still use separate contact voltage regulators and separate DC power supplies.In view of the problems of poor output accuracy,trouble in maintenance,disordered lines and inconvenience in use when multiple power supplies are required for the experimental research,the purpose of this research is to propose a multi-channel AC/DC output voltage regulating power supply,which can provide adjustable multichannel AC/DC power supply when multiple power supplies are required for the experiment.Based on the analysis of various classic topologies,a new main circuit structure is designed,which uses three-level conversion,and the front stage uses the PWM rectifier circuit controlled by DSP to convert the mains power into stable DC with high power factor.The intermediate stage uses a multiple-output isolated full-bridge converter,uses a multi-winding high-frequency transformer to realize two DC bus outputs,and uses a control chip UCC3895 to realize open-loop control.The latter stage circuit adopts inverter and buck converter respectively,with STM32 chip as the core.Through sampling voltage and current signal and comparing with the given value,PI control algorithm is adopted,and the AC and DC independent regulation output is realized by modulating SPWM modulation ratio and chopping duty ratio.Aiming at the problems of power supply fluctuation,load disturbance,power grid harmonic pollution and so on,which lead to the fluctuation of DC output of PWM rectifier,and then affect the fluctuation of DC bus output of full-bridge converter,an auto-disturbance rejection control of PWM rectifier based on PI-VPI is proposed.The auto-disturbance rejection controller is used in the voltage outer loop to improve the anti-interference ability of DC bus voltage,and the PI-VPI controller is used to improve the dynamic performance of the system,At the same time,reduce the harmonic pollution of power supply to the power grid.In order to verify the correctness of the power supply topology and control system,a simulation model of the power supply system was constructed on the MATLAB/Simulink simulation platform,and an experimental platform was built.The input voltage of the power supply was 220 V,the voltage range of the AC output port was 0-300 V,and the voltage range of the DC output port was 0-300 V.Through the analysis of simulation and experimental waveforms,the power supply can be adjusted within the voltage regulation range,and the output accuracy is within 5%.The effectiveness of the main power topology and control strategy of the designed power supply was verified,and the results showed that the designed power supply can quickly and accurately achieve multi-channel AC/DC voltage regulation output,and has good anti-interference ability.