Asymmetric cascaded H-bridge (ACHB) trinary inverter has several advantages, such as high efficiency due to high power main H-bridge modulated under a fundamental low frequency, optimal modulation due to nonredundant output voltage levels, and reduction in output filter sizes due to high-quality staircase output waveform. However, ACHB inverter requires prestage isolated dc sources for the individual H-bridges and has inherent control issues of nonregenerative operation, being incompatible with photovoltaic source. This article proposes a single-stage, single-sourced ACHB trinary inverter topology without presources. Then, a control strategy using unity horizon length finite-control-set model predictive control (FCS-MPC) is proposed to modulate the ACHB inverter. Conventional unity horizon length FCS-MPC has presence of undesirable harmonics and chaos in its variable frequency switching waveform due to the minimum achievable error. Therefore, an exact discrete-time modeling for FCS-MPC is newly derived to show the nonlinear effects of power stage and control parameters in the closed-loop dynamics. And then, a bifurcation analysis-based design is proposed to eliminate the undesirable harmonics and chaos operation in the FCS-MPC closed-loop operation. The proposed topology and FCS-MPC controller design is implemented and verified in hardware by using a 2-kW prototype for standalone and grid-connected operation.

中文翻译：

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有限控制集模型预测控制辅助浮动电容光伏单源三元逆变器建模与分岔分析

非对称级联 H 桥 (ACHB) 三元逆变器具有多个优点，例如由于在基频低频下调制的高功率主 H 桥实现高效率、由于非冗余输出电压电平实现的最佳调制以及由于高品质阶梯输出波形。然而，ACHB 逆变器需要用于单个 H 桥的前级隔离直流电源，并且具有非再生操作的固有控制问题，与光伏电源不兼容。本文提出了一种无预源的单级、单源 ACHB 三元逆变器拓扑。然后，提出了一种使用统一水平长度有限控制集模型预测控制（FCS-MPC）的控制策略来调制 ACHB 逆变器。由于可达到的最小误差，传统的单位水平长度 FCS-MPC 在其可变频率切换波形中存在不希望有的谐波和混沌。因此，新推导出 FCS-MPC 的精确离散时间建模，以显示闭环动态中功率级和控制参数的非线性效应。然后，提出了一种基于分岔分析的设计，以消除 FCS-MPC 闭环操作中的不良谐波和混沌操作。所提出的拓扑结构和 FCS-MPC 控制器设计通过使用用于独立和并网运行的 2 kW 原型在硬件中实现和验证。新推导出 FCS-MPC 的精确离散时间建模，以显示闭环动态中功率级和控制参数的非线性效应。然后，提出了一种基于分岔分析的设计，以消除 FCS-MPC 闭环操作中的不良谐波和混沌操作。所提出的拓扑结构和 FCS-MPC 控制器设计通过使用用于独立和并网运行的 2 kW 原型在硬件中实现和验证。新推导出 FCS-MPC 的精确离散时间建模，以显示闭环动态中功率级和控制参数的非线性效应。然后，提出了一种基于分岔分析的设计，以消除 FCS-MPC 闭环操作中的不良谐波和混沌操作。所提出的拓扑结构和 FCS-MPC 控制器设计通过使用用于独立和并网运行的 2 kW 原型在硬件中实现和验证。