Topology, Efficiency Analysis, and Control of a Four-Level $\pi$ -Type Converter

Jin, Bosen; Yuan, Xibo

doi:10.1109/jestpe.2018.2875485

Cited by 39 publications

(44 citation statements)

References 44 publications

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“…The experimental results can verify the feasibility of the 4L hybrid converter and the effectiveness of the control method, and the phenomena of the undesired voltage jumps can be significantly decreased by using the adjusted switching states, which can effectively reduce the switching voltage stress (dv/dt) and improve the performance of the line voltage. Regarding efficiency, the 4L converter can have a higher efficiency than 2L and 3L converters at high switching frequencies due to a lower switching loss, as proved by Reference [27]. In future, the component parameters of the 4L hybrid converter will be optimized to provide the optimal efficiency.…”

Section: Output Frequency 50hzmentioning

confidence: 94%

Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter

et al. 2019

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In low and medium voltage power conversion systems, multilevel converters are becoming more and more attractive due to improved power density. However, the complexity of topology and control is a big challenge for the application of multilevel converters. In this paper, a four-level (4L) hybrid flying capacitor (FC) T-type converter has been researched in detail. The topological advantage of the converter is displayed in comparison to existing four-level converters. According to the feature of the topology, the operating status has been analyzed and the reason for the voltage jump is researched in detail during the dead-time period. A strategy to reduce voltage jump by adjusting the switching states has be presented. The FC voltages can be balanced by selecting the appropriate switching states. The relationships between the fluctuations of FC voltages and the modulation index and power factor (PF) have been analyzed by simulation results. The performance of the 4L converter has been investigated in MATLAB/Simulink as well as on a down-scaled laboratory prototype.

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Section: Output Frequency 50hzmentioning

confidence: 94%

Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter

et al. 2019

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“…where V on0 represents the equivalent on-state threshold voltage of six switches, and r represents the equivalent on-resistance [5]. The direction of i o is defined as:…”

Section: States Vonmentioning

confidence: 99%

“…[1][2][3][4]. Additionally, three-level or four-level converters are also considered for low-voltage fields to improve the power-density and power-quality [5,6].…”

Section: Introductionmentioning

confidence: 99%

Operation and Control of a Seven-Level V-Clamp Multilevel Converter

et al. 2019

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Multilevel converters are well suited for high-power and high-quality power conversion. This paper presents a new seven-level V-clamp multilevel converter (VMC) with reduced clamping devices. All phases of the VMC share common DC-link capacitors and realize bidirectional power conversion without flying capacitors. Each branch of the VMC sustains only a single-level voltage of the DC-link capacitors during its commutation process. Hence, the series switches can be controlled as simple as one switch and the dynamic voltage unbalancing issue is avoided. In this paper, the operation principle and the modulation method of the VMC are analyzed in detail. In addition, compensation control for non-ideal factors is designed to improve the output performance. The output fundamental distortion is compensated and the harmonics are reduced. Finally, a laboratory prototype of the seven-level VMC is set up to verify the feasibility of the presented topology and analysis.

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“…Compared to a conventional two-level converter, the benefits of multilevel topologies include lower dV/dt, lower output harmonics and lower switching loss. As an available candidate of the multilevel converter topologies, the π-type topology was proposed and has been actively researched over the past years [1]- [4]. The π-type topology is essentially a fourlevel converter in the Neutral-Point Clamped (NPC) family with reduced device count (six devices per phase leg).…”

Section: Introductionmentioning

confidence: 99%

“…1. The main challenge in a π-type converter is to maintain the middle capacitor voltage, especially under unity power factor [1]- [3]. In order to operate normally, the three DC-link capacitors voltages must maintain at 1/3 of the whole DC-link voltage.…”

Section: Introductionmentioning

confidence: 99%

Closed-loop DC-link Voltage Balancing Algorithm for a Four-level π-type Converter

Wang

Yuan

Jin

et al. 2019

IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society

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A four-level π-type converter is a Neutral Point Clamped (NPC) multilevel converter topology for low/medium voltage applications. As the inherent issue with this topology, the DC-link capacitor voltage balancing is challenging, especially when it operates as a single-end inverter/rectifier with unity power factor. This paper proposes a closed-loop DC-link voltage balancing algorithm of a π-type converter that is effective and simple to implement. In principle, this approach is based on Redundant Level Modulation (RLM). The RLM utilizes additional voltage levels in each switching window to gain extra controllability of the DC-link capacitor voltages without affecting the average output voltage. An algorithm based on mathematical and logical operations is developed to utilize RLM to achieve the closed-loop voltage balancing. The proposed control method is effective over the full modulation index (M = 0 ~ 1.15) and full power factor range (cos φ = 0 ~ 1). The algorithm is implemented in a test rig, and the experiment confirms its effectiveness.

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Topology, Efficiency Analysis, and Control of a Four-Level $\pi$ -Type Converter

Abstract: His research interests include multilevel converter topologies, control and power loss analysis.

Cited by 39 publications

References 44 publications

Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter

Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter

Operation and Control of a Seven-Level V-Clamp Multilevel Converter

Closed-loop DC-link Voltage Balancing Algorithm for a Four-level π-type Converter

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