Hybrid PWM Strategy for Power Efficiency Improvement of 5-Level TNPC Inverter and Current Distortion Compensation Method
Department of Electrical Engineering, Konkuk University, Seoul 05029, Korea
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Electronics 2019, 8(1), 76; https://doi.org/10.3390/electronics8010076
Received: 18 November 2018 / Revised: 31 December 2018 / Accepted: 4 January 2019 / Published: 10 January 2019
(This article belongs to the Special Issue Renewable Electric Energy Systems)
This paper proposes a pulse width modulation (PWM) strategy for improving the efficiency of a 5-level H-bridge T-type neutral point clamped (TNPC) inverter. In the case of the proposed PWM strategy, unlike the conventional PWM strategy in which both of the switching legs of the H-bridge inverter operate at a high frequency, one switching leg of the inverter operates at a low frequency. As the switching frequency is lowered, the switching loss is reduced, this improving the efficiency of the system. The duty references for the switching legs and the operating principle of the inverter are described in detail. The proposed PWM strategy, however, causes distortion of the output filter inductor current. The cause of the distortion has been analyzed and a compensation method is proposed to mitigate the distortion of the current. The effect of the proposed PWM strategy can be predicted through the loss calculation of the inverter for each modulation strategy. Furthermore, current distortion mitigation obtained by compensation method is confirmed through the simulation. In order to verify the effectiveness of the proposed strategy, a 2 kW H-bridge TNPC inverter prototype is implemented and tested. The simulation and experimental results show that the efficiency of the inverter is improved when the proposed PWM strategy is applied.
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Keywords:
T-type neutral point clamped (TNPC) inverter; pulse width modulation (PWM) strategy; power efficiency improvement; current distortion compensation
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MDPI and ACS Style
Lee, T.; Bu, H.; Cho, Y. Hybrid PWM Strategy for Power Efficiency Improvement of 5-Level TNPC Inverter and Current Distortion Compensation Method. Electronics 2019, 8, 76. https://doi.org/10.3390/electronics8010076
AMA Style
Lee T, Bu H, Cho Y. Hybrid PWM Strategy for Power Efficiency Improvement of 5-Level TNPC Inverter and Current Distortion Compensation Method. Electronics. 2019; 8(1):76. https://doi.org/10.3390/electronics8010076
Chicago/Turabian StyleLee, Taeyeong; Bu, Hanyoung; Cho, Younghoon. 2019. "Hybrid PWM Strategy for Power Efficiency Improvement of 5-Level TNPC Inverter and Current Distortion Compensation Method" Electronics 8, no. 1: 76. https://doi.org/10.3390/electronics8010076
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