Abstract This work introduces a generalized methodology for mathematical modelling and controller design of a single-phase cascaded H-bridge multilevel-converter comprising the connection of N H-bridges, which results in 2 N + 1 voltage levels. Towards this end, the average model of the converter is first transformed into a decoupled mathematical structure based on a new definition of state variables. Out of this, the control objectives, current tracking and voltage regulation, are decoupled from the voltage balance problem for such a general case of N H-bridges. To show the benefits of the proposed methodology, a shunt active power filter application has been considered in this paper, where the control objectives are the compensation of the power factor and harmonic distortion due to nonlinear loads, plus regulation and balance of all DC-bus voltages. In particular, this work focus on the balance issue, which leads to the design of N - 1 balance loops. A tuning strategy is also introduced to design the gains of the proposed control scheme, which are based on time scale separation and a desired closed-loop transient performance. The proposed generalized methodology is evaluated in a 7-level cascaded H-bridge converter both through simulations and experimentally.

中文翻译：

---

基于模型的单相 n 电平 CHB 多电平转换器控制器

摘要 这项工作介绍了一种用于数学建模和控制器设计的通用方法，该方法包括连接 N 个 H 桥的单相级联 H 桥多电平转换器，从而产生 2 N + 1 个电压电平。为此，转换器的平均模型首先被转换为基于状态变量的新定义的解耦数学结构。因此，对于 N H 桥的这种一般情况，控制目标、电流跟踪和电压调节与电压平衡问题分离。为了展示所提出方法的好处，本文考虑了并联有源电力滤波器应用，其中控制目标是补偿非线性负载引起的功率因数和谐波失真，加上所有直流母线电压的调节和平衡。特别是，这项工作侧重于平衡问题，这导致了 N-1 个平衡回路的设计。还引入了一种调整策略来设计所提出的控制方案的增益，其基于时间尺度分离和所需的闭环瞬态性能。通过仿真和实验在 7 级级联 H 桥转换器中评估所提出的通用方法。