A Simplified Virtual Vector PWM Algorithm to Balance the Capacitor Voltages of Four-Level Diode-Clamped Converter

Qamar, Muhammad Attique; Wang, Kui; Zheng, Zedong; Wang, Shien

doi:10.1109/access.2020.3028444

Cited by 22 publications

(8 citation statements)

References 56 publications

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“…Other methods propose the regulation of the dwell times of the switching states to balance the NPC, for 3-level [122] and for 4-level [123] or, at least, to reduce the output voltage distortion [95].…”

Section: Closed-loop Techniquesmentioning

confidence: 99%

A Survey on Capacitor Voltage Control in Neutral-Point-Clamped Multilevel Converters

et al. 2022

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Neutral-point-clamped multilevel converters are currently a suitable solution for a wide range of applications. It is well known that the capacitor voltage balance is a major issue for this topology. In this paper, a brief summary of the basic topologies, modulations, and features of neutral-point-clamped multilevel converters is presented, prior to a detailed description and analysis of the capacitor voltage balance behavior. Then, the most relevant methods to manage the capacitor voltage balance are presented and discussed, including operation in the overmodulation region, at low frequency-modulation indexes, with different numbers of AC phases, and with different numbers of levels. Both open- and closed-loop methods are discussed. Some methods based on adding external circuitry are also presented and analyzed. Although the focus of the paper is mainly DC–AC conversion, the techniques for capacitor voltage balance in DC–DC conversion are discussed as well. Finally, the paper concludes with some application examples benefiting from the presented techniques.

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Section: Closed-loop Techniquesmentioning

confidence: 99%

A Survey on Capacitor Voltage Control in Neutral-Point-Clamped Multilevel Converters

et al. 2022

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“…The total power loss, P L is the sum of conduction and switching losses, which is represented in the following: P L = P CL,DIODE + P CL,IGBT + P SL,DIODE + P SL,IGBT (19) The equation below is used to calculate the efficiency, η of the converter, in which P O stands for the output power of the converter:…”

Section: Analysis Of Power Loss and Efficiencymentioning

confidence: 99%

“…As for DCMI, there are two possible solutions that can be adopted to overcome the unbalanced voltage problem. One solution is via the modification of the pulsewidth modulation (PWM) switching pattern [17][18][19][20][21]. The switching pattern is normally selected from the redundant switching states.…”

Section: Introductionmentioning

confidence: 99%

Capacitor Voltage Balancing with Online Controller Performance-Based Tuning for a Switch-Sharing-Based Multilevel Inverter

et al. 2021

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Switch-sharing-based multilevel inverters offer great advantages in terms of efficiency improvement and output quality enhancement for low-power photovoltaic (PV) applications. However, the capacitor voltage balancing issue may critically deteriorate the output voltages, and thus could nullify the aforementioned benefits. Hence, this paper proposes a capacitor voltage balancing solution based on a buck-boost converter with performance-based tuning controllers to address the issue. The proposed controllers are designed based on the proportional-integral (PI) configuration equipped with an online tuning mechanism. The main purpose of the online tuning mechanism is to fine tune the proportional gain according to the DC input voltage, based on the measured output current total harmonic distortion (THD) performance of the inverter, while at the same time preventing the controller from reaching a state of saturation. By using the actual measurement of current THD performance, online tuning accuracy can be improved since no ideal condition is assumed, and thus, the associated error can be minimized. Simulation and experimental results reveal that the capacitor voltages can be balanced at high modulation indexes with improved current harmonic performance able to be be acquired at the inverter’s output.

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“…A generalized mechanism for investigating the capacitor voltage imbalance in the four-level topologies was provided in [27]. The three capacitor currents [23], [27], [31]- [34] or using voltage-balance circuitry [35], [36]. The variable-carrier scheme (VCS) can effectively control the voltage balance among the three capacitors [27], [34], thus it is chosen to balance the capacitor voltages in this work.…”

Section: Voltage Balancing Control Of the Dc-link Capacitorsmentioning

confidence: 99%

Four-Level Three-Phase Inverter With Reduced Component Count for Low and Medium Voltage Applications

2021

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This paper proposes a novel three-phase topology with a reduced component count for lowand medium-voltage systems. It requires three bidirectional switches and twelve unidirectional switches for producing four-level voltages without using flying capacitors or clamping diodes, reducing the size, cost, and losses. Removing flying capacitors and clamping diodes allows it to simplify control algorithms and increase the reliability, efficiency, and lifetime. A modified low-frequency modulation (LFM) scheme is developed and implemented on the proposed topology to produce a staircase voltage with four steps. Further, a level-shifted pulse width modulation (LSPWM) is used to reduce the filter size and increase the output voltage controllability. In this study, a voltage balancing control algorithm is executed to balance the DC-link capacitor voltages. The performance of the proposed topology is numerically demonstrated and experimentally validated on an in-house test setup. Within the framework, the power loss distribution in switches and conversion efficiency of the proposed circuit are studied, and its main features are highlighted through a comparative study.INDEX TERMS DC-AC converters, four-level inverters, low and medium voltage applications, multilevel inverters, three-phase inverters.

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A Simplified Virtual Vector PWM Algorithm to Balance the Capacitor Voltages of Four-Level Diode-Clamped Converter

Cited by 22 publications

References 56 publications

A Survey on Capacitor Voltage Control in Neutral-Point-Clamped Multilevel Converters

A Survey on Capacitor Voltage Control in Neutral-Point-Clamped Multilevel Converters

Capacitor Voltage Balancing with Online Controller Performance-Based Tuning for a Switch-Sharing-Based Multilevel Inverter

Four-Level Three-Phase Inverter With Reduced Component Count for Low and Medium Voltage Applications

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