A closed-loop voltage balance method for five-level diode-clamped inverters

Cui, Dongdong; Ge, Qiongxuan; Zhou, Zhida; Yang, Bo

doi:10.1109/iecon.2017.8216089

Cited by 12 publications

(2 citation statements)

References 16 publications

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“…The second option is the Zero-sequence Signal Injection (ZSI) [18], [19], which is equivalent to the nearest three vector (NTV) [20]- [22] approach in Space Vector Modulation (SVM), utilizing the redundancy in between phase voltages that cancels out in the line voltages. The ZSI approach is widely used in three-level converters [18], [19], while it is reported to significantly lose its effectiveness in a single-end 5L-NPC converter under a high power factor cos φ and a high modulation index M, as demonstrated in [12], [23]. As a solution to ease the problem, the active-front-end (back-to-back) configuration is applied to extend the operating range of a 5L-NPC converter [9], [10], [15], [24]- [26].…”

Section: Introductionmentioning

confidence: 99%

Fast-Processing Capacitor Voltage Balancing Algorithm for Single-End Five-Level NPC Converters Based on Redundant Level Modulation

Wang,

Zhou,

et al. 2024

IEEE Trans. Power Electron.

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Five-level neutral point clamped (5L-NPC) topologies have been proposed for the medium-voltage grid and drive applications since the 1990s. However, their practical implementation has been hindered due to the inherent capacitor voltage drift issue, especially in a single-end configuration. This work proposes a fast-processing, carrier-based voltage balancing algorithm to address this issue, which is based on the latest redundant level modulation (RLM) concept. The proposed approach is fully based on closed-form expressions and basic logic operations, which can be straightforwardly programmed in microcontrollers, as enabled by a fully transparent mathematical model. In contrast, the existing methods treat it as a black box problem, which requires mandatory PI/PID controllers that complicate the implementation. This method shows effective and superior voltage balancing performance against existing methods without affecting the converter output capacity throughout all operating conditions. The fundamental principles and analysis of the capacitor operation are presented to enable a better understanding of the problem and its solution. This work also evaluates the increased switching actions as a side effect of the RLM operation, which is the mandatory cost for all known modulation-based voltage balancing approaches for 5L-NPC converters. For comparison across different systems, a new normalization term is proposed to quantify the capacitor voltage ripples for evaluation with the switching frequency factored in.

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Section: Introductionmentioning

confidence: 99%

Fast-Processing Capacitor Voltage Balancing Algorithm for Single-End Five-Level NPC Converters Based on Redundant Level Modulation

Wang,

Zhou,

et al. 2024

IEEE Trans. Power Electron.

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“…The NPC inverters are used for high power AC motor drive applications, which have been studied to increase efficiency of trains (1) (2) . However, they have a disadvantage of the charge imbalance of capacitors, which need complicated modulation methods or extra circuits (3) (4) . The CHB inverters are used for very high power applications which demand power quality; static var compensator and distributed generations using renewable energy (1) (5) .…”

Section: Introductionmentioning

confidence: 99%

Multilevel Inverter Topology Using Current Path Change for Zero Current Switching

2019

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In motor drive applications, a high switching frequency is required to mitigate current harmonics, which cause a copper loss. However, the high switching frequency makes the switching loss large. Hence, some switching loss reduction techniques have been studied in the past. These techniques have some problems. This paper proposes a multilevel inverter topology for switching loss reduction. Because of provision of multiple current paths, the proposed inverter realizes the zero current switching. Consequently, a loss of the whole system including an inverter and motor can be reduced with a higher switching frequency. The switching loss of the proposed inverter is smaller than that of the conventional one. It was verified that the proposed inverter has some advantages at high switching frequency, through calculations.

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