Extended Virtual-Flux Decoupling Hysteresis Control for Mains Connected Three-Level NPC Inverter Systems

An extended approach which adapts the VirtualFlux Decoupling Hysteresis Control initially employed for the conventional two-level VSI to a three-level NPC inverter is proposed in this paper. To extract the benefits of this topology, namely low output harmonic distortion and lower switches blocking voltage, the classical single-band hysteresis strategy must be modified and the balance of the mid-point potential have to be guaranteed. The mid-point voltage is controlled by influencing the zero sequence current generated in the decoupling loop. The method is adapted to be used with an LCL output filter, where some undesirable characteristics, such as filter resonance, have to be compensated. Theoretical analysis is presented and the performance of the proposed method is verified by simulation.

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

[2]  M. Marchesoni.  High performance current control techniques for applications to multilevel high power voltage source inverters , 1989 .

[3]  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.

[4]  U. Drofenik,et al.  Space vector based analysis of the variation and control of the neutral point potential of hysteresis current controlled three-phase/switch/level PWM rectifier systems , 1995, Proceedings of 1995 International Conference on Power Electronics and Drive Systems. PEDS 95.

[5]  Paolo Tomasin,et al.  Improved constant-frequency hysteresis current control of VSI inverters with simple feed-forward bandwidth prediction , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[6]  Alberto Bellini,et al.  A new approach to hysteresis modulation techniques for NPC inverters , 2002, Industrial Electronics, 2002. ISIE 2002. Proceedings of the 2002 IEEE International Symposium on.

[7]  Marian P. Kazmierkowski,et al.  Simple direct power control of three-phase PWM rectifier using space-vector modulation (DPC-SVM) , 2004, IEEE Transactions on Industrial Electronics.

[8]  U. Drofenik,et al.  A novel hysteresis current control for three-phase three-level PWM rectifiers , 2005, Twentieth Annual IEEE Applied Power Electronics Conference and Exposition, 2005. APEC 2005..

[9]  J.W. Kolar,et al.  A modified direct power control strategy allowing the connection of three-phase inverter to the grid through LCL filters , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[10]  L.A. Serpa,et al.  A Virtual-Flux Decoupling Hysteresis Current Controller for Mains Connected Inverter Systems , 2007, IEEE Transactions on Power Electronics.