This paper describes the operation of reduced-switch single DC source cascaded H-bridge multilevel inverter (RSDCHBMLI). Compared to conventional multilevel inverters, RSDCHBMLI offers a number of advantages such as lower component count, inherent isolation and requirement of single DC source. The paper proposes application of RSDCHBMLI as DSTATCOM in a weak distribution system. The usage of single DC-link capacitor in this topology eliminates the problem of capacitor voltage balancing in DSTATCOM operation. The DSTATCOM is operated in current controlled mode (CCM) using Finite control set-Model predictive control (FCS-MPC). FCS-MPC is successful in independently performing load compensation in presence of feeder impedance along with maintaining sinusoidal voltages at the point of common coupling (PCC), without the need of any modulator or supplementary control techniques. This paper also explores different control schemes used for maintaining the DC-bus voltage. A current based proportional-integral (PI) DC-bus voltage controller is implemented in this paper, which allows easier calculation of the controller gain parameters. The performance of the current based controller is also compared with conventional power based DC-bus controllers in terms of steady state error and settling time. The results are presented for a 11-kV distribution system with RSDCHBMLI based DSTATCOM simulated in PSCAD/EMTDC environment.

本文介绍了减少开关的单直流源级联 H 桥多电平逆变器 (RSDCHBMLI) 的操作。与传统的多电平逆变器相比，RSDCHBMLI 具有许多优点，例如组件数量少、固有隔离和对单个直流电源的要求。本文提出了在弱配电系统中将 RSDCHBMLI 作为 DSTATCOM 的应用。在此拓扑中使用单个直流链路电容器消除了 DSTATCOM 操作中的电容器电压平衡问题。DSTATCOM 使用有限控制集模型预测控制 (FCS-MPC) 在电流控制模式 (CCM) 下运行。FCS-MPC 在馈线阻抗存在的情况下成功地独立执行负载补偿，同时在公共耦合点 (PCC) 处保持正弦电压，无需任何调制器或辅助控制技术。本文还探讨了用于维持直流母线电压的不同控制方案。本文实施了基于电流的比例积分 (PI) 直流母线电压控制器，可以更轻松地计算控制器增益参数。还在稳态误差和稳定时间方面将基于电流的控制器的性能与传统的基于功率的直流总线控制器进行了比较。结果是针对在 PSCAD/EMTDC 环境中模拟的具有基于 RSDCHBMLI 的 DSTATCOM 的 11 kV 配电系统提供的。这允许更容易地计算控制器增益参数。还在稳态误差和稳定时间方面将基于电流的控制器的性能与传统的基于功率的直流总线控制器进行了比较。结果是针对在 PSCAD/EMTDC 环境中模拟的具有基于 RSDCHBMLI 的 DSTATCOM 的 11 kV 配电系统提供的。这允许更容易地计算控制器增益参数。还在稳态误差和稳定时间方面将基于电流的控制器的性能与传统的基于功率的直流总线控制器进行了比较。结果是针对在 PSCAD/EMTDC 环境中模拟的具有基于 RSDCHBMLI 的 DSTATCOM 的 11 kV 配电系统提供的。