Improved switching loss calculation in neutral point clamped inverter via waveforms linearization

An improved switching loss calculation method for IGBT switching on, switching off and the diode reverse recovery energy losses in neutral point clamped inverter is proposed in this paper. A model of linear instantaneous switching on and off waveforms is presented to approximate actual switching process. The IGBT switching on and off duration, the changing rates of current di/dt and collector-emitter voltage dv/dt all can be calculated at different load currents with the given IGBT parameters. Besides, the proposed method is apparently different from the linear waveform method used before which assuming switching time to be a constant value. In addition, compared with the traditional mathematical equation that uses measured data to fit a formula, the equation proposed here is based on physical model and it can indicate the relationship between gate drive resistor, the IGBT capacitance, trans-conductance and switching process. An inverter employing a switching pattern as sinusoidal PWM (SPWM) was designed and experiment was carried out to test the switching waveforms under different output currents. Switching loss under different currents was also measured and compared with calculated value using mathematical equation proposed in this paper.

[1]  Frede Blaabjerg,et al.  Optimum design and test of a snubberless IGBT PWM-VSI inverterbridge , 1994, Proceedings of 1994 IEEE Industry Applications Society Annual Meeting.

[2]  J. Schonberger,et al.  Modelling turn-off losses in power diodes , 2008, 2008 11th Workshop on Control and Modeling for Power Electronics.

[3]  Chang-xin Miao,et al.  Research on Switching Loss Minimized PWM Method for Flying Capacitor Three-Level Inverters , 2010, 2010 International Conference on Electrical and Control Engineering.

[4]  Sibylle Dieckerhoff,et al.  Simple methods to calculate IGBT and diode conduction and switching losses , 2009, 2009 13th European Conference on Power Electronics and Applications.

[5]  Feng Chai,et al.  Analysis of modulation pattern and losses in inverter for PMSM drives , 2008, 2008 IEEE Vehicle Power and Propulsion Conference.

[6]  D.V. Korobkov,et al.  A principle of calculation dynamic and static power losses with hard-switching IGBT , 2005, Proceedings. 6th Annual. 2005 International Siberian Workshop and Tutorials on Electron Devices and Materials, 2005..

[7]  P. Krein,et al.  IGBT and Diode Loss Estimation Under Hysteresis Switching , 2012, IEEE Transactions on Power Electronics.

[8]  Bin Wu,et al.  Switching loss analysis of modulation methods used in neutral point clamped converters , 2009, 2009 IEEE Energy Conversion Congress and Exposition.

[9]  Dong-Seok Hyun,et al.  The analysis of conduction and switching losses in multi-level inverter system , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[10]  J. Rodriguez,et al.  Switching loss analysis of modulation methods used in cascaded H-bridge multilevel converters , 2008, 2008 IEEE Power Electronics Specialists Conference.