ABSTRACT:
KEYWORDS:
1. Power
conversion
2. Ac-dc
power conversion
3. Rectifiers
4. Dc
power systems
5. Wind
energy
6. Maximum
power point trackers
7. Wind
energy generation
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Figure
1. (a) Wind turbine power-point tracking architecture: the prime mover is a
variable-speed wind turbine. The turbine shares a common shaft with the multi-port
PMSG. Ac power is converted to dc by an integrated generator-rectifier system.
The dc output is connected to a stiff dc interface. The integrated generator-rectifier
system performs maximum power-point tracking to extract the turbine maximum power.
EXPECTED SIMULATION RESULTS:
Figure
2. (a) (Top plot) The active rectifier d-axis and q-axis currents track the
reference command, presented by the dotted lines. The dc-bus current varies
accordingly by changing the d-axis current, leading to a change in the dc-bus
power (bottom plot). (b) The relationship between dc-bus power and active-rectifier
d-axis current acquired from the simulation model (recorded by the markers)
matches the theoretical analysis (plotted by the lines using equation (6)).
Figure
3. Waveforms to illustrate the system MPPT capability. (a) At each wind speed,
the turbine speed (solid-blue line) successfully tracks the optimal speed to generate
maximum power. (b) The dc-bus power and the turbine mechanical power versus
time. (c) The d-axis and q-axis currents to achieve MPPT.
Figure
4. Generator phase-A back emf, phase-A current, and power of the passive and
active rectifiers at different operating speeds. (a) Sinusoidal and phase-shifted
back emfs at the rated generator speed. (b) The corresponding phase-A currents.
(c) Sharing of PMSG input power between ac ports powering active versus passive
rectifiers. (d) Back emfs at the minimum operating speed that is equal to 55%
the rated speed. (e) Phase-A currents corresponding to the minimum speed. (f)
Power sharing between the ac ports powering active and passive rectifiers at
the minimum operating speed.
CONCLUSION:
This paper presents an MPPT methodology for an integrated generator-rectifier
system. An analytical relationship between the dc-bus power and the active
rectifier d-axis current is established and validated using both simulation and
experiment. A cascaded control architecture is proposed for practical
implementation. The inner loop comprises PI current controllers with
feed-forward terms, while the outer loop is a PI power controller. Satisfactory
power tracking performance has been accomplished. The power flow control
enables the wind turbine MPPT through controlling the dc-bus power. This capability
opens up opportunities for the integrated generator rectifier systems in wind
energy applications.
REFERENCES:
[1]
P. Huynh, S. Tungare, and A. Banerjee, “Maximum power point tracking for wind
turbine using integrated generator-rectifier systems,” in 2019 IEEE Energy
Conversion Congress and Exposition (ECCE), Sep. 2019, pp. 13–20.
[2]
D. S. Ottensen, “Global offshore wind market report,” Norweigian Energy
Partner, Tech. Rep., 2018.
[3]
C. Bak, R. Bitsche, A. Yde, T. Kim, M. H. Hansen, F. Zahle, M. Gaunaa, J. P. A.
A. Blasques, M. Døssing, J.-J. W. Heinen et al., “Light rotor: The 10-MW
reference wind turbine,” in EWEA 2012-European Wind Energy Conference &
Exhibition. European Wind Energy Association (EWEA), 2012.
[4]
P. Higgins and A. Foley, “The evolution of offshore wind power in the united
kingdom,” Renewable and sustainable energy reviews, vol. 37, pp. 599–612, 2014.
[5]
W. Musial, P. Beiter, P. Spitsen, J. Nunemaker, and V. Gevorgian, “2018
offshore wind technologies market report,” National Renewable Energy
Laboratory, https://www.energy.gov/eere/wind/downloads/2018-
offshore-wind-market-report, Tech. Rep., 2018.