Control Of
Parallel Multiple Converters For Direct-Drive Permanent-Magnet Wind Power
Generation Systems
ABSTRACT:
This paper proposes control strategies for mega watt
level direct-drive wind generation systems based on permanent magnet
synchronous generators. In the paper, a circulating current model is derived
and analyzed. The parallel-operation controllers are designed to restrain
reactive power circulation and beat frequency circulation currents caused by
discontinuous space vector modulation. The control schemes do not change the
configurations of the system consisting of parallel multiple converters. They
are easy to implement for modular designs and large impedance required to equalize
the current sharing is not needed. To increase the system reliability, a robust
adaptive sliding observer is designed to sense the rotor position of the wind
power generator. The experimental results proved the effectiveness of the
control strategies.
KEYWORDS:
1.
Circulation
currents
2.
Parallel multiple converters
3.
Permanent magnet synchronous generators
(PMSGs)
4.
Wind power
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.1. High-Power Direct-Drive PMSG Wind Generator
System Connected To The Power Grid.
CONCLUSION:
This
paper has comprehensively addressed the control issues of parallel three-phase
PWM converters for the permanent magnet wind power generation systems. The
major accomplishments and some conclusions are summarized in the following.
1)
A peak current model of zero-sequence currents has been derived and analyzed
for the three-phase PWM converters in parallel connection.
2)
A zero-sequence current control scheme has been adapted to reject the
zero-sequence current inside an individual converter.
3)
An adaptive observer has been integrated with parallel operation control
experimentally. The performance of position sensorless control of the generator
has been greatly enhanced and the reliability has been increased.
4)
Zero-sequence currents have been successfully suppressed for the back-to-back
converters with parallel connection. Large impedance needed to equalize the
current sharing has been removed.
5)
Experimental verification of the control of the three-phase PWM converters in
parallel confirms the good performance and promising features of the proposed
directly driven permanent magnet synchronous power generation system.
REFERENCES:
[1]
T. Kawabata And S. Higashino, “Parallel Operation Of Voltage Source Inverters,”
Ieee Trans. Ind. Appl., Vol. 24, No. 2, Pp. 281–287, Mar./Apr. 1988.
[2]
J. Holtz, W. Lotzkat, And K. H. Werner, “A High-Power Multi-Transistorinverter Uninterruptable
Power Supply System,” Ieee Trans. Power Electron., Vol. 3, No. 3, Pp.
278–285, Jul. 1988.
[3]
L. H.Walker, “10mwgto Converter For Battery Peaking Service,” Ieee Trans.
Ind. Appl., Vol. 26, No. 1, Pp. 63–72, Jan./Feb. 1990.
[4]
S. Fukuda And K. Matsushita, “A Control Method For Parallel-Connected Multiple
Inverter Systems,” Presented At The 7th Int. Conf. Power Electron. Variable
Speed Drives, London, U.K., 1998.
[5]
X. Kun, F. C. Lee, D. Boroyevich, Y. Zhihong, And S. Mazumder, “Interleaved Pwm
With Discontinuous Space-Vector Modulation,” Ieee Trans. Power
Electron., Vol. 14, No. 5, Pp. 906–917, Sep. 1999.
