ABSTRACT:
In this paper,
a novel PWM technique insuring the self-balancing of the capacitors voltages
has been proposed for the attained nine-level packed U cells (PUC) converter.
In the traditional fifteen-level operation, the capacitors voltages have to be
maintained around their references using a state variable feedback which
requires three sensors, two for the capacitors voltages and one for the load
current. By applying the proposed PWM technique to the fifteen-level PUC
converter, self balancing of the capacitors voltages is attained, which results
in the proposed nine-level converter. The proposed balancing technique is
achieved without any closed loop regulation or sensors. The proposed concept has
been verified by mean of simulations performed in the Matlab Simulink
environments. Simulation results show that even under severe DC bus voltage and
load parameters variations, the capacitors voltages remains around their
required values. Harmonics contents of load current depend on the modulating
signal frequency. Moreover, even under low frequencies, the total harmonics
distortion remains reduced.
KEYWORDS:
1. Packed U cells
2. Multilevel converters
3. Self balancing
4. PWM technique
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
A sensor-less self balancing PWM
technique applied to the fifteen-level PUC inverter was presented in this
paper. It allows a fast open loop regulation of the PUC inverter capacitors
voltages without using any additional circuit. Indeed, the self balancing is
achieved without using any state variable feedback or sensors. The proposed
concept was verified by simulation results.
REFERENCES:
[1] Y. Ounejjar and K. Al-Haddad "A
novel high energetic efficiency multilevel topology with reduced impact on
supply network", The 34th Annual Conference of the IEEE
Industrial Electronics Society, pp.489-494, 10-13 November 2008, Orlando,
Florida, USA
[2]- Ounejjar, Y., K. Al-Haddad et L.
Gregoire.. "Packed U Cells Multilevel Converter Topology: Theoretical
Study and Experimental Validation". IEEE Transactions on Industrial
Electronics, vol. 58, n°4, p.1294-1306, (April 2011).
[3] X. h. Zhang and W. k. Yue,
"Neutral point potential balance algorithm for three-level NPC inverter
based on SHEPWM," in Electronics Letters,vol. 53, no. 23, pp.
1542-1544, 11 9 2017
[4] M. Sleiman, K. Al-Haddad, H. F.
Blanchette and H. Y. Kanaan, "Insertion Index Generation Method Using
Available Leg–Average Voltage to Control Modular Multilevel Converters,"
in IEEE Transactions on Industrial Electronics, vol. PP, no. 99, pp.
1-1.
[5] I. López et al.,
"Modulation Strategy for Multiphase Neutral-Point- Clamped
Converters," in IEEE Transactions on Power Electronics, vol. 31, no.
2, pp. 928-941, Feb. 2016.
