An Optimized Zero-Sequence Voltage Injection Method for Eliminating Circulating Current and Reducing Common Mode Voltage of Parallel-Connected Three-Level Converters

2020 ◽  
Vol 67 (8) ◽  
pp. 6583-6596 ◽  
Author(s):  
Xiangyang Xing ◽  
Xiaoyan Li ◽  
Changwei Qin ◽  
Jie Chen ◽  
Chenghui Zhang
Keyword(s):  
Common Mode ◽  
Injection Method ◽  
Common Mode Voltage ◽  
Circulating Current ◽  
Zero Sequence ◽  
Zero Sequence Voltage

scholarly journals A Novel Low Common-Mode Voltage Modulation Strategy for ANPC-5L Inverter

2020 ◽  
Vol 185 ◽  
pp. 01015
Author(s):  
Fusheng Wang ◽  
Sai Weng ◽  
Lizhong Ye ◽  
Tao Chen
Keyword(s):  
Harmonic Distortion ◽  
Output Current ◽  
Space Vector ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Zero Sequence ◽  
Implementation Method ◽  
Bus Voltage ◽  
Vector Modulation ◽  
Zero Sequence Voltage

In order to suppress the leakage current of the active neutral point clamed five-level (ANPC-5L) inverter, this paper proposes a novel low common-mode voltage (CMV) modulation strategy based on the space vector modulation thought. Only the 55 voltage vectors with low CMV amplitude instead of all 125 voltage vectors are utilized. The CMV amplitude is suppressed to one-twelfth of the DC bus voltage (Vdc). In the simplified five-level space vector diagram, “obtuse triangle” synthesis principle is used to control the CMV changes twice in each carrier cycle, and get lower output current total harmonic distortion (THD). According to the vector thought, a carrier implementation method based on zero sequence voltage injection and carrier splitting is proposed. This method simplifies the calculation and is easy to implement.Simulation results prove the correctness and feasibility of this low CMV modulation strategy.

scholarly journals A Carrier-Based Discontinuous PWM Strategy of NPC Three-Level Inverter for Common-Mode Voltage and Switching Loss Reduction

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 3041
Author(s):  
Guozheng Zhang ◽  
Yingjie Su ◽  
Zhanqing Zhou ◽  
Qiang Geng
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Balance Control ◽  
Neutral Point ◽  
Switching Loss ◽  
Major Drawback ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Zero Sequence ◽  
Zero Sequence Voltage

For the conventional carrier-based pulse width modulation (CBPWM) strategies of neutral point clamped (NPC) three-level inverters, the higher common-mode voltage (CMV) is a major drawback. However, with CMV suppression strategies, the switching loss is relatively high. In order to solve the above issue, a carrier-based discontinuous PWM (DPWM) strategy for NPC three-level inverter is proposed in this paper. Firstly, the reference voltage is modified by the twice injection of zero-sequence voltage. Switching states of the three-phase are clamped alternatively to reduce both the CMV and the switching loss. Secondly, the carriers are also modified by the phase opposite disposition of the upper and lower carriers. The extra switching at the border of two adjacent regions in the space vector diagram is reduced. Meanwhile, a neutral-point voltage (NPV) control method is also presented. The duty cycle of the switching state that affects the NPV is adjusted to obtain the balance control of the NPV. Still, the switching sequence in each carrier period remains the same. Finally, the feasibility and effectiveness of the proposed DPWM strategy are tested on a rapid control prototype platform based on RT-Lab.

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