A novel DC-link voltage balancing algorithm for a 3-level neutral point clamped (NPC) traction inverter for an electric vehicle IPMSM drive

This paper presents a novel DC-link voltage balancing algorithm for a 3-level DC/AC traction inverter drive. In this topology, two DC-link capacitor voltages and three-phase line currents are measured, to generate the control pulses for the traction inverter, based on space-vector pulse width modulation (SV-PWM) scheme. Depending on the states of the two DC-link capacitors, redundant voltage vector sequences are used, to keep the capacitor voltages within a particular tolerance level. Phase current directions are also taken into account, because below a certain power factor level, it affects the capacitor voltage balancing capability. Simulation and experimental results are presented in this paper for a 6.0 kW interior permanent magnet synchronous machine (IPMSM) used for the electric vehicle (EV) traction applications. Both the simulation and experimental results show required performance of the proposed system.

[1]  T. Suzuki,et al.  An improved voltage vector control method for Neutral-Point-Clamped inverters , 1994, Proceedings of 1994 Power Electronics Specialist Conference - PESC'94.

[2]  Thomas M. Jahns,et al.  Flux-Weakening Regime Operation of an Interior Permanent-Magnet Synchronous Motor Drive , 1987, IEEE Transactions on Industry Applications.

[3]  S. Bernet,et al.  A comparison of three-level converters versus two-level converters for low-voltage drives, traction, and utility applications , 2005, IEEE Transactions on Industry Applications.

[4]  F. Wang.  Multilevel PWM VSIs , 2004, IEEE Industry Applications Magazine.

[5]  Dushan Boroyevich,et al.  Evaluation of the low-frequency neutral-point voltage oscillations in the three-level inverter , 2005, IEEE Transactions on Industrial Electronics.

[6]  Hirofumi Akagi,et al.  A New Neutral-Point-Clamped PWM Inverter , 1981, IEEE Transactions on Industry Applications.

[7]  A.M. Hava,et al.  A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[8]  Mark Sumner,et al.  Neutral point control for multi-level inverters: theory, design and operational limitations , 1997, IAS '97. Conference Record of the 1997 IEEE Industry Applications Conference Thirty-Second IAS Annual Meeting.

[9]  H. Akagi,et al.  Analysis of variation of neutral point potential in neutral-point-clamped voltage source PWM inverters , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[10]  B. P. Schmitt,et al.  Retrofit of fixed speed induction motors with medium voltage drive converters using NPC three-level inverter high-voltage IGBT based topology , 2001, ISIE 2001. 2001 IEEE International Symposium on Industrial Electronics Proceedings (Cat. No.01TH8570).

[11]  D. Boroyevich,et al.  Limits of the neutral-point balance in back-to-back-connected three-level converters , 2004, IEEE Transactions on Power Electronics.

[12]  Pragasen Pillay,et al.  Modified DC-link voltage balancing algorithm for a 3-level neutral point clamped (NPC) traction inverter based electric vehicle PMSM drive , 2013, IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society.

[13]  Pragasen Pillay,et al.  DC-Link Voltage Balancing for a Three-Level Electric Vehicle Traction Inverter Using an Innovative Switching Sequence Control Scheme , 2014, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[14]  Dushan Boroyevich,et al.  A fast space vector modulation algorithm for multilevel three-phase converters , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).