A study on the multi-carrier PWM methods for voltage balancing of flying capacitor in the flying capacitor multi-level inverter

The voltage control of flying capacitor is very important for safe operation in flying capacitor multi-level inverter (FCMLI). The voltage unbalancing of flying capacitor causes serious problems in safety and reliability of system, and also limits FCMLI's applications. The voltage unbalancing is occurred due to the difference of each capacitors charging and discharging time applied to FCMLI. This paper investigates and analyzes multi-carrier PWM methods to solve capacitor voltage balancing problem. Among the various PWM methods for the FCMLI, the phase-shift PWM (PSPWM) method, the modified carrier-redistribution PWM (MCRPWM) method and the saw-tooth-rotation PWM (STRPWM) method are discussed and compared with respect to switching state, balancing voltage of capacitors and output waveform. Also, this paper considers the performance of PWM methods. These three PWM methods are analyzed in the flying capacitor three-level inverter. The results are shown through simulation and experiment. Finally, the harmonics about the output voltages of their methods are compared using the harmonic distortion factor (HDF)

[1]  I. Barbi,et al.  Investigation on the clamping voltage self-balancing of the three-level capacitor clamping inverter , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[2]  Vassilios G. Agelidis,et al.  Analysis of multicarrier PWM methods for a single-phase five level inverter , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[3]  Dong-Seok Hyun,et al.  The carrier-based PWM method for voltage balance of flying capacitor multilevel inverter , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[4]  Dong-Seok Hyun,et al.  A symmetric carrier technique of CRPWM for voltage balance method of flying-capacitor multilevel inverter , 2005, IEEE Transactions on Industrial Electronics.

[5]  Dong-Seok Hyun,et al.  An Improved Carrier-Based SVPWM Method Using Leg Voltage Redundancies in Generalized Cascaded , 2003 .

[6]  Fang Zheng Peng,et al.  Multilevel inverters: a survey of topologies, controls, and applications , 2002, IEEE Trans. Ind. Electron..

[7]  D. S. Hyun,et al.  Simple harmonic analysis method for multi-carrier PWM techniques using output phase voltage in multi-level inverter , 2005 .

[8]  Dong-Seok Hyun,et al.  Carrier-rotation strategy for voltage balancing in flying capacitor multilevel inverter , 2004 .

[9]  T.A. Meynard,et al.  Multi-level conversion: high voltage choppers and voltage-source inverters , 1992, PESC '92 Record. 23rd Annual IEEE Power Electronics Specialists Conference.