A Neutral Point Voltage Balancing Method for Multi-Level GTO Inverters

The balancing problem of the DC-link capacitor voltage is inherent in the NPC inverter. It is extremely important to keep the upper and lower DC-link capacitor voltages balanced to guarantee the three level operation of the inverter. Generally, the balancing of the DC-link voltage degrades at very low operating frequencies of the inverter. Most proposed methods of neutral point balancing techniques result in an increase of the switching losses of the inverter. To solve this problem a new energy saving PWM method is proposed. This results in a significant reduction of the fluctuations of the neutral point voltage of NPC inverters. Furthermore, the proposed method incorporates techniques to avoid the inherent minimum ON-OFF pulse width limitation in a GTO, without increasing the switching losses of the devices. Theoretical and practical aspects as well as the experimental results are presented in this paper

[1]  P. Enjeti,et al.  Optimal power control strategies for neutral point clamped (NPC) inverter topology , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[2]  L. Ben-Brahim,et al.  Improvement of a PWM controlled NPC GTO inverter for AC motor drives , 1999, ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465).

[3]  Gyu-Hyeong Cho,et al.  DSP based space vector PWM for three-level inverter with DC-link voltage balancing , 1991, Proceedings IECON '91: 1991 International Conference on Industrial Electronics, Control and Instrumentation.

[4]  Susumu Tadakuma,et al.  Consideration on PWM Control for Neutral Point Clamped Inverter , 1992 .

[5]  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.

[6]  Rae-Young Kim,et al.  A novel SVPWM strategy considering DC-link balancing for a multi-level voltage source inverter , 1999, APEC '99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285).

[7]  M. Swamy,et al.  Neutral-point clamped three-level general purpose inverter - features, benefits and applications , 2004, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551).

[8]  L.M. Tolbert,et al.  Novel multilevel inverter carrier-based PWM methods , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[9]  Yongdong Li,et al.  A direct torque control of induction motor based on three-level NPC inverter , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[10]  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.

[11]  K.R.M.N. Ratnayake,et al.  Novel PWM scheme to control neutral point voltage variation in three-level voltage source inverter , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[12]  Ivo Barbi,et al.  Soft-switched three-level capacitor clamping inverter with clamping voltage stabilization , 2000 .

[13]  Dushan Boroyevich,et al.  A comprehensive study of neutral-point voltage balancing problem in three-level neutral-point-clamped voltage source PWM inverters , 2000 .

[14]  G. Sciutto,et al.  A new multilevel PWM method: a theoretical analysis , 1990, 21st Annual IEEE Conference on Power Electronics Specialists.

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

[16]  S. Tadakuma,et al.  Fundamental approaches to PWM control based GTO inverters for linear synchronous motor drives , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.

[17]  A. von Jouanne,et al.  Multilevel inverter modulation schemes to eliminate common-mode voltages , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[18]  Seung-Ki Sul,et al.  A new PWM strategy for common mode voltage reduction in neutral-point clamped inverter-fed AC motor drives , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[19]  Seung-Ki Sul,et al.  A new discontinuous PWM strategy of neutral-point clamped inverter , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[20]  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.

[21]  T. Habetler,et al.  Novel Multilevel Inverter Carrier-Based PWM Method , 2000 .

[22]  H.L. Liu,et al.  Three-level space vector PWM in low index modulation region avoiding narrow pulse problem , 1993, Proceedings of IEEE Power Electronics Specialist Conference - PESC '93.

[23]  L. Ben-Brahim,et al.  A novel multilevel carrier-based PWM-control method for GTO inverter in low index modulation region , 2003, IEEE Transactions on Industry Applications.

[24]  A. von Jouanne,et al.  A simple method for balancing the DC-link voltage of three-level inverters , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[25]  Keiju Matsui,et al.  Application of parallel connected NPC-PWM inverters with multilevel modulation for AC motor drive , 2000 .

[26]  L. Ben-Brahim,et al.  A new PWM control for GTO minimum on-pulse compensation , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[27]  Dong-Seok Hyun,et al.  A new simplified space-vector PWM method for three-level inverters , 1999, APEC '99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285).

[28]  Tokuo Ohnishi,et al.  An improved voltage vector control method for Neutral-Point-Clamped inverters , 1994 .

[29]  Fei Wang,et al.  Sine-triangle vs. space vector modulation for three-level PWM voltage source inverters , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[30]  Dong-Seok Hyun,et al.  A novel PWM scheme for a three-level voltage source inverter with GTO thyristors , 1994, Proceedings of 1994 IEEE Industry Applications Society Annual Meeting.