Voltage Balancing Control of Hybrid Stacked Multicell Converters Based on Modified Phase-Shifted PWM

Abstract

The hybrid stacked multicell converter (HSMC) is a competitive converter in the lowvoltage high-efficiency applications. Proper modulation and voltage balancing control are important for the operation of the HSMC, which may ensure the HSMC to obtain high-quality output and low power losses. A hybrid phase-shifted PWM (PS-PWM) with the modified reference signal is developed for nine-level HSMC (9L-HSMC), and the neutral point voltage can be naturally balanced in a fundamental cycle. Based on the hybrid PS-PWM, an active voltage balancing control is put forward for the flying capacitor (FC). The voltage balancing of FC is implemented by slightly modifying the reference signals to adjust the duty cycles of the high-frequency switches symmetrically. This method does not need complex calculations, and it can be easily extended to higher level HSMC and other FC-based configurations. The simulations are carried out to validate the merits of low power losses and superior power quality. A downscale experimental platform of a 9L-HSMC is a setup to verify the effectiveness of the proposed control strategy under both the steady state and the transient states. INDEX TERMS Multilevel converter, neutral point (NP) voltage, phase-shifted PWM (PS-PWM), stacked multicell converter (SMC), voltage balancing control.

Dual-Stage Control Strategy for a Flying Capacitor Converter Based on Model Predictive and Linear Controllers

“…Depending on the topology, it is possible to move the internal states to their references by using an appropriate standard modulation stage [21], or including more sophisticated modulation schemes [22,23], without any significant effect…”

Model predictive control of a hybrid stacked multicell converter with voltage balancing and fault tolerance capability

“…To evaluate the effectiveness of the proposed control strategy, the power losses of the 9L-HSMC including switching loss and conduction loss are studied. The conduction losses are determined by the on-state equivalent resistance and forward voltage drops, while the switching losses are estimated by the linear approximation of voltage and current through kth switch [32]. The power losses were calculated by MATLAB/Simulink based on the constructed loss models.…”

New Approach of Multi-Cell Stacked Cell Inverter for Solar Photovoltaic System

“…Three-level neutral-point-clamped (NPC) converter has been widely used in high-power motor drives and renewable energy conversions. However, as the number of voltage level increases, the clamping diodes and unbalanced loss distribution will be fast increased [13]. In recent years, hybrid multilevel converters have been proposed and compared to popular multilevel topologies, they require fewer switches and FCs [14] [15].…”

“…Active neutral-point-clamped (ANPC) converter is a newly introduced hybrid multilevel converter (HMC), which combines the advantages of the NPC and FC converters. Three-level ANPC and several five-level ANPC topologies have been put forward in [13]. In this configuration, to generate a high number of voltage levels, the number of diodes is increased slightly, which limits applications of this topology.…”