Seven
Level Shunt Active Power Filter for
High
Power Drive Systems
ABSTRACT:
In high-power adjustable-speed motor drives, such as
those used in electric ship propulsion systems, active filters provide a viable
solution to mitigating harmonic related issues caused by diode or thyristor
rectifier front-ends. To handle the large compensation currents and provide better
thermal management, two or more paralleled semiconductor switching devices can
be used. In this paper, a novel topology is proposed where two active filter inverters
are connected with tapped reactors to share the compensation currents. The
proposed active filter topology can also produce seven voltage levels, which
significantly reduces the switching current ripple and the size of passive
components. Based on the joint redundant state selection strategy, a current
balancing algorithm is proposed to keep the reactor magnetizing current to a minimum.
It is shown through simulation that the proposed active filter can achieve high
overall system performance. The system is also implemented on a real-time
digital simulator to further verify its effectiveness.
KEYWORDS:
1.
Active filters
2.
Harmonic
analysis
3.
Power
conversion
4.
Power electronics.
SOFTWARE: MATLAB/SIMULINK
BLOCK
DIAGRAM:
Fig. 1. Active filter connection
to a shipboard power system.
CIRCUIT DIAGRAM:
Fig. 2. Proposed seven-level
active filter topology.
CONCLUSION:
A
new type of power converter has been introduced in this paper. The converter is
based on parallel connection of phase legs through an interphase reactor.
However, the reactor has an off center tap at one-third resulting in an
increased number of voltage levels. Specifically, two three-level flying
capacitor phase legs are paralleled in this way to form a seven-level power converter.
The converter is utilized in an active filter application. The details of the
high-level control as well as the switching control have been presented. The
control ensures reactor current sharing as well as flying capacitor voltage
balance. The proposed active filter has been validated for a naval ship board
power system using detailed simulation and RTDS hardware.
REFERENCES:
[1]
B. Singh, K. Al-Haddad, and A. Chandra, “A review of active filters for power
quality improvement,” IEEE Trans. Ind. Electron., vol. 46, no. 5, pp.
960–971, Oct. 1999.
[2]
S. Bhattacharya, T.M. Frank, D. M. Divan, and B. Banerjee, “Active filter system
implementation,” IEEE Ind. Appl. Mag., vol. 4, no. 5, pp. 47–63, Sep.
1998.
[3]
Z. Du, L. M. Tolbert, and J. N. Chiasson, “Active harmonic elimination for
multilevel converters,” IEEE Trans. Power Electron., vol. 21, no. 2, pp.
459–469, Mar. 2006.
[4]
M. E. Ortuzar, R. E. Carmi, J. W. Dixon, and L. Moran, “Voltage-source active
power filter based on multilevel converter and ultracapacitor DC link,” IEEE
Trans. Ind. Electron., vol. 53, no. 2, pp. 477–485, Apr. 2006.
[5]
B. R. Lin and T. Y. Yang, “Analysis and implementation of a three-level active
filter with a reduced number of power semiconductors,” Proc. Inst. Electr.
Eng. Electr. Power Appl., vol. 152, no. 5, pp. 1055–1064, Sep. 2005.
