Effect of Pulse Width Modulation Methods on Power Losses and Thermal Loadings of Single-Phase 5-Level NPC Inverters for PV Systems

전압 변조 방법에 따른 단상 5-레벨 NPC 태양광 인버터의 전력 손실 및 열 부하 분석

  • Ryu, Taerim (Dept. of IT Media Engineering, Seoul National University of Science and Technology) ;
  • Choi, Ui-Min (Dept. of Electronic & IT Media Engineering, Seoul National University of Science and Technology)
  • 류태림 ;
  • 최의민
  • Received : 2021.09.06
  • Accepted : 2021.11.15
  • Published : 2022.02.20


In this paper, the effect of pulse width modulation methods on thermal loadings and power losses of single-phase five-level NPC inverters for photovoltaic systems are analyzed. The pulse width modulation methods affect the power losses of the NPC inverters and thus lead to different thermal loadings of NPC inverters. To identify the reliability-critical power device with respect to thermal stress, the thermal loadings of I- and T-type NPC inverters are analyzed by applying the unipolar pulse modulation method. Then, the effect of the discontinuous pulse width modulation method on power losses and thermal loadings of power devices of I- and T-type NPC inverters are analyzed. Finally, the operation of NPC inverters applying the discontinuous pulse modulation method is confirmed by experiments. The results show that the discontinuous pulse modulation method is able to improve the reliability of NPC inverters by reducing thermal loadings of reliability-critical power devices and it is more effective for T-type NPC inverters than I-type NPC inverters.



이 성과는 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임. (No. 2019R1F1A1057164)


  1. S. Yang, A. Bryant, P. Mawby, D. Xiang, L. Ran, and P. Tavner, "An industry-based survey of reliability in power electronic converters," IEEE Transactions on Industry Applications, Vol. 47, pp. 1441-1451, May/Jun. 2011.
  2. U. Choi, F. Blaabjerg, and K. Lee, "Study and handling methods of power IGBT module failures in power electronic converter systems," IEEE Transactions on Power Electronics, Vol. 30, No. 5, pp. 2517-2533, May 2015.
  3. H. Wang, M. Liserre, F. Blaabjerg, P. de Place Rimmen, J. B. Jacobsen, T. Kvisgaard, and J. Landkildehus, "Transitioning to physics-of-failure as a reliability driver in power electronics," IEEE Journal of Emerging and Selected Topics in Power Electronics, Vol. 2, No. 1, pp. 97-114. Mar. 2014.
  4. Handbook for Robustness Validation of Automotive Electrical/Electronic Modules, ZVEL, Frankfurt, Germany, Jun. 2008.
  5. H. Wang, K. Ma, and F. Blaabjerg, "Design for reliability of power electronic systems," in Proc. Ind. Electron. Soc. Conf., pp. 33-44, 2012.
  6. M. Ciappa, "Selected failure mechanism of modern power modules," Microelectronics Reliability, Vol. 42, No. 4-5, pp. 653-667, Apr./May 2002.
  7. U. M. Choi, F. Blaabjerg, and S. Jorgensen, "Power cycling test methods for reliability assessment of power device modules in respect to temperature stress," IEEE Transactions on Power Electronics, Vol. 33, No. 3, pp. 2531-2551, Mar. 2018.
  8. A. Volke and M. Hornkamp, IGBT modules: Technologies, driver and applications, 1st ed., Infineon Technologies AG, Munich, Germany, ch. 4, 2011.
  9. Mitsubishi Electric, "Power module reliability," pp. 1-13. [Online]. Available: