ABSTRACT:
This
paper proposes a new five-level hybrid topology combining features of neutral
point clamped and flying capacitor inverters. The proposed topology provides a
tradeoff between different component counts to achieve a good loss
distribution, avoid direct series connection of semiconductor devices, keep the
balanced operation of dc-link capacitors while keeping the number of costly
components such as capacitors and switches low. The required modulation
strategy is developed and the operation of the proposed topology is studied.
The features of the proposed topology are investigated and compared to other
available topologies. Simulation results are provided to verify the performance
of the converter for medium voltage applications
KEYWORDS:
1 .Multilevel Inverter,
2. Flying Capacitor,
3. Active Neutral Point Clamped,
4. Diode Clamped.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. A phase leg of the proposed 5-level hybrid topology.
EXPECTED SIMULATION RESULTS:
Fig. 2. Simulation results. (a) Phase voltage (b) Line voltage
(c) Flying capacitor voltages (d) Load current
frequency 5kHz. The dc-link voltage is set at 18kV and flying capacitors
are 330μF. It can be seen that even without an RLC balance booster, the
capacitor voltage errors are limited to less than 4%.
CONCLUSION:
A new hybrid 5-level inverter topology and modulation technique
is proposed. Compared to 5-level ANPC as the most similar topology, this new
topology requires two less switches at the cost of an additional capacitor and
six diodes. However, since the capacitors still see the switching frequency and
their size remain the same, it is expected to reduce the inverter’s
total cost. Also, unlike 5-level ANPC, all switches must
withstand the same voltage which eliminates the need for series connection of
switches and associated simultaneous turn on
and off problem. Good loss distribution among switches can
increase the inverters rated power or provide
higher switching frequency and smaller capacitor size.
REFERENCES:
[1] H. Abu-Rub, J. Holtz, and J. Rodriguez,
“Medium-Voltage Multilevel Converters—State of the Art, Challenges, and
Requirements in Industrial Applications,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2581–2596, Aug. 2010.
[2] S. Kouro, M. Malinowski, K. Gopakumar,
J. Pou, L. G. Franquelo, J. Rodriguez, M. A. Pérez, and J. I. Leon, “Recent
Advances and Industrial Applications of Multilevel Converters,” IEEE Trans. Ind. Electron.,
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[3] M. Malinowski, K. Gopakumar, J.
Rodriguez, and M. A. Pérez, “A Survey on Cascaded Multilevel Inverters,” IEEE Trans. Ind. Electron.,
vol. 57, no. 7, pp. 2197–2206, Jul. 2010.
[4] J. Rodriguez, “Multilevel inverters: a
survey of topologies, controls, and applications,” IEEE Trans. Ind. Electron., vol. 49, no. 4, pp. 724–738, Aug. 2002.
[5] J. Rodriguez, S. Bernet, P. K. Steimer,
and I. E. Lizama, “A Survey on Neutral-Point-Clamped Inverters,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2219–2230, Jul. 2010.
