Two-stage single-phase inverter system has found many applications in distributed generators and grid-connected systems. However, the existence of double-line frequency ripple on the dc-bus voltage due to single-phase inverter's operation has given rise to some design and reliability issues. Some of these are the degradation in the quality of inverter's output voltage and shortening of dc-bus capacitor's lifetime. The problem is rooted in the controller design of the front-end dc-dc converter, which is often designed based on a simplified mathematical model of the dc-dc converter that fails to account for some complex phenomena, such as system's nonlinearities and circuit parameter variations due to temperature and aging effects. In this paper, a disturbance-observer-based control is proposed where these unmodeled effects are treated in the form of lumped disturbance and compensated for in a feed-forward manner. The major advantage of this control solution is that only minimal plant information is needed for controller design and that a decoupled composite controller can be realized, where the feedback compensator is designed to meet certain stability criteria while the disturbance-observer-based feed-forward compensator is designed to handle fast transient events. A prototype of a dual-active-bridge (DAB) dc-dc converter implemented with disturbance-observer-based control is constructed to verify its effectiveness. Experimental results show that the dynamic response of the DAB converter is significantly improved and the double-line frequency ripple on the dc-bus voltage is effectively suppressed by the proposed control solution.

中文翻译：

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基于干扰观测器的直流母线电压控制，可减轻两级单相逆变器系统中的纹波并改善动态响应


两级单相逆变器系统在分布式发电机和并网系统中得到了广泛的应用。然而，由于单相逆变器运行，直流母线电压上存在双线频率纹波，引起了一些设计和可靠性问题。其中一些是逆变器输出电压质量下降和直流母线电容器寿命缩短。该问题的根源在于前端DC-DC转换器的控制器设计，该设计通常是基于简化的DC-DC转换器数学模型来设计的，无法考虑一些复杂现象，例如系统的非线性和电路参数由于温度和老化影响而产生的变化。在本文中，提出了一种基于扰动观测器的控制，其中这些未建模的效应以集总扰动的形式处理，并以前馈方式进行补偿。该控制解决方案的主要优点是控制器设计只需要最少的被控对象信息，并且可以实现解耦复合控制器，其中反馈补偿器设计为满足某些稳定性标准，而基于扰动观测器的前馈补偿器旨在处理快速瞬态事件。构建了采用基于扰动观测器的控制实现的双有源桥 (DAB) DC-DC 转换器原型，以验证其有效性。实验结果表明，所提出的控制方案显着改善了DAB转换器的动态响应，并且有效抑制了直流母线电压上的双线频率纹波。