A new approach is proposed here to control the two-level three-phase grid side converter. The proposed control strategy is an extended state observer (ESO)-based adaptive control, consists of two cascaded control loops. The adaptive-multi-input multi-output controller is employed in the inner control loop, which is used to regulate the active and reactive component of the grid currents. The outer-loop consists of an adaptive controller augmented with an ESO to regulate the DC bus voltage. The goal of the proposed control strategy is to maintain a unity power factor while keeping the DC bus voltage constant under a sudden change in load demand at DC side, i.e. change in the resistive load connected across the DC bus. The proposed adaptive controller in the inner control loop does not require any information about the parameters associated with the grid filter (L-filter), and hence, it is found to be more robust towards parametric variations. The ESO-based adaptive controller is compared with the classical proportional–integral control in real-time, and the comparison indicates that the proposed controller not only accomplishes a nearly flawless tracking performance but also delivers a complete robust performance against resistive load variation across the DC bus.

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具有广泛参数和负载不确定性的三相电网侧变流器自适应控制策略的开发

在此提出一种新的方法来控制两级三相电网侧变换器。所提出的控制策略是基于扩展状态观察器（ESO）的自适应控制，由两个级联的控制回路组成。内部控制回路中采用了自适应多输入多输出控制器，该控制器用于调节电网电流的有功和无功分量。外环由自适应控制器组成，该控制器增加了ESO以调节DC总线电压。提出的控制策略的目标是在直流侧负载需求突然变化（即，跨直流母线连接的电阻性负载变化）下，保持单位功率因数同时保持直流母线电压恒定。内部控制回路中提出的自适应控制器不需要有关与网格滤波器（L滤波器）相关的参数的任何信息，因此，发现它对参数变化更加健壮。基于ESO的自适应控制器与经典比例积分控制进行了实时比较，比较结果表明，所提出的控制器不仅实现了近乎完美的跟踪性能，而且还提供了针对整个直流电阻负载变化的完整鲁棒性能总线。