使用传统控制器的LLC谐振变换器,在负载变化频繁时,会出现输出电压超调大和调节时间长等问题.为此提出一种基于模型辅助自抗扰控制(Model-assisted active disturbance rejection control,MADRC)策略.首先在扩展描述函数法的基础上,建立LLC谐振变换器的小信号模型,通过降阶处理得到LLC变换器的传递函数.然后提出将模型辅助自抗扰控制应用于LLC谐振变换器的电压环路中,详细介绍模型辅助自抗扰控制器的设计过程,对比系统经过PID控制器、线性自抗扰控制器和模型辅助自抗扰控制器补偿后的伯德图.最后为验证设计效果,搭建了一台额定功率为300 W的试验样机.通过对PID控制器、线性自抗扰控制器(Linear active disturbance rejection control,LADRC)和模型辅助自抗扰控制器三种控制器的对比试验,证明了模型辅助自抗扰控制器在负载扰动下具有更好的快速性和鲁棒性.
Model-assisted Active Disturbance Rejection Control of LLC Resonant Converter
When the load changes frequently,the main issues in LLC resonant converters with traditional controllers are large overshoot of the output voltage and long regulation time.To solve above issues,a model-assisted active disturbance rejection control(MADRC)is proposed.First,based on the extended describing function method,the small-signal model of the LLC resonant converter is established.Then,the transfer function of the LLC converter is obtained through order reduction.Next,the application of MADRC in the voltage loop of the LLC resonant converter is proposed,and the detailed design process of the MADRC controller is presented,and the Bode diagram of the system after compensation by PID controller,linear active disturbance rejection controller and model-assisted active disturbance rejection controller is compared.Finally,the operation and performance of the proposed control strategy are verified with a 300 W LLC resonant.Comparative experiments are conducted among PID controller,linear active disturbance rejection control(LADRC)and model-assisted active disturbance rejection control.The results demonstrate that the model-assisted active disturbance rejection control exhibits better performance in terms of fast response and robustness under load disturbances.
LLC resonant convertermodel-assisted active disturbance rejection controllerlinear active disturbance rejection controller
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