Analysis and suppression of a common mode resonance in the cascaded H-bridge multilevel inverter

The common mode (CM) voltage and current issues due to the parasitic ground capacitance have been well reported for the PWM converters. However, most of the previous work focused on the CM voltage generated at the motor side, or the input/output filter design for the standard compliance purpose. This paper identified a unique ground loop resonance phenomenon for the cascaded H-bridge multilevel inverter, which is generated internally due to the stray inductance of the bridge interconnection cable and the bus-to-ground parasitic capacitance. This resonance will increase the voltage and current stress in the power stage and therefore reduce the reliability of the system. The mechanism of the resonance is analyzed in detail and the corresponding suppression approach is discussed, proposing the preferred CM choke placement scheme. Simulation and experimental results provided verification of the resonance analysis and the effectiveness of the proposed suppression approach.

[1]  T.A. Lipo,et al.  Reduced common mode carrier-based modulation strategies for cascaded multilevel inverters , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[2]  N. Zargari,et al.  Comparison and mitigation of common mode voltage in power converter topologies , 2004, Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting..

[3]  J. Sabate,et al.  High-bandwidth high-power gradient driver for magnetic resonance imaging with digital control , 2005, Twentieth Annual IEEE Applied Power Electronics Conference and Exposition, 2005. APEC 2005..

[4]  Sun Xing-tao,et al.  A New Multilevel Space Vector PWM Technique for H-bridge Cascaded Inverter , 2007, 2007 2nd IEEE Conference on Industrial Electronics and Applications.

[5]  A.K. Gupta,et al.  A Space Vector Modulation Scheme to Reduce Common Mode Voltage for Cascaded Multilevel Inverters , 2007, IEEE Transactions on Power Electronics.

[6]  Pinggang Song,et al.  Reduce Common-Mode Voltage in Cascaded Multilevel Inverter Based on Artificial Neural Network , 2006 .

[7]  Prasad Enjeti,et al.  Analysis of common mode voltage-"neutral shift" in medium voltage PWM adjustable speed drive (MV-ASD) systems , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[8]  J. Sabate,et al.  Ripple cancellation filter for magnetic resonance imaging gradient amplifiers , 2004, Nineteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2004. APEC '04..

[9]  Leon M. Tolbert,et al.  Multilevel converters for large electric drives , 1999 .