Study On An Ac Electronic Load Considering Dead-time Effect

With the intellectualization of production and life,all kinds of power supplies have been widely used.In order to ensure the quality of the power supply,its performance needs to be tested before leaving the factory.The traditional power supply test adopts the real load with high test accuracy,but there are some disadvantages,such as inflexible load parameter adjustment,waste of energy,large floor area and so on.Therefore,it is necessary to study an electronic load which can not only improve the shortcomings of the traditional load test,but also ensure the test accuracy.In this paper,an AC electronic load considering dead-time effect and its compensation is studied,Firstly,the main circuit structure of PWM rectifier AC electronic load is designed,and the common topology,modulation method and four quadrant operation principle of PWM rectifier are introduced,and the working principle and working mode of PWM rectifier AC electronic load are analyzed.Secondly,based on the classical control strategy of PWM rectifier,a target current control strategy combining feedforward and closed-loop is proposed.The addition of feedforward compensates the error caused by the voltage drop of AC side inductance and resistance,and improves the control accuracy and stability of the system.Then,the dead-time effect of AC electronic load based on PWM rectifier is analyzed combined with target current control,and three simulation accuracy indexes related to dead-time are obtained,which quantitatively express the influence of deadtime effect on impedance simulation accuracy of AC electronic load for the first time.Next,the voltage error compensation method,the dead-time compensation method based on pulse conversion and the subsection dead-time elimination method are studied.In the subsection dead-time elimination method,an accurate threshold calculation method suitable for PWM rectifier-type AC electronic load is proposed to compensate the dead-time effect better,and the correctness of the dead-time effect analysis and the remarkable effect of the compensation are verified by simulation.Finally,a PWM rectifier-type AC electronic load experimental prototype is designed and built,and the experimental results verify the correctness of the proposed control strategy and analysis,as well as the effect of dead-time compensation.