Resonant Inverter Shunt IGBT Equalization Control Strategy Research

With the increasing demands for clean high-power electric energy devices,the use of high-power semiconductor IGBTs in parallel is becoming a trend.The reliability and safety of the power supply is affected by the uneven current distribution problem when IGBTs are used in parallel to increase the output power of the power supply.In this paper,based on the traditional active gate-level control technology,the parallel IGBT current equalization control for resonant inverters was studied coupled with Variable-Domain Fuzzy Control,Differential Evolution algorithm,and RBF neural network.The research mainly includes:Firstly,relevant factors that may cause parallel IGBT unequal currents were analyzed.At the same time,the related influencing factors of parallel IGBT current disproportion,such as the consistency of device parameters,the strength of driving signal,as well as the magnitude of driving resistance,were verified using simulation software,which provided theoretical foundation for the determination of current equalization strategies.Secondly,aiming at the shortcoming of traditional active gating techniques which is Overly dependent on expert experience and difficult to obtain control parameters in Static homogeneous flow,a control strategy for active gating techniques.which used variable-domain fuzzy control Is proposed.Fuzzy control rules are established directly from the output characteristics of IGBTs in the data sheet the effectiveness of the method and its performance superiority over conventional control are also verified by simulation.Finally,because turn-on and turn-off delay time of IGBT used in delay compensation of driving pulses in dynamic current sharing is difficult to obtain,the IGBT turn-on and turn-off delay time prediction model based on RBF neural network is established,which combined with tests results.Then,the turn-on and turn-off delay time of IGBT can be predicted directly according to the existing IGBT operating circuit environment parameters.The accuracy of prediction and the effect of dynamic current sharing using prediction results of the time prediction were verified by simulation experiment.In summary,variable-domain fuzzy control and time prediction model were used to improve the active gate-level control technology in this paper,the uneven parallel IGBT currents are effectively improved,and good current balance effect is obtained.