LVRT Enhancement of DFIG-based WECS using SVPWM-based Inverter
Control
Authors: Purushothaman Srinivasan , Samiappan Dhandapani , Kamalkannan Muralikrishna , Joseph Nissy , Murugavel Roshan 
Published: June 2023

Across many countries, wind turbine generation systems (WTGS) have been established
over the past few decades. In this paper, we augment the low voltage ride-through (LVRT) enrichment
facility of driving a DFIG-based wind energy conversion system (WECS) using space vector
pulse width modulation (SVPWM)-based inverter control. The proposed technique employs an
SVPWM-based control algorithm to regulate the voltage and frequency of the output power during
grid faults, thereby enhancing the WECS's ability to remain connected to the grid and provide power.
The study focuses on decreasing transient current throughout the instant of fault. Modeling and
control approaches were also discussed in this study. The performance of the proposed technique is
evaluated using MATLAB/Simulink simulations, and the results demonstrate that the technique effectively
improves the LVRT capability of the DFIG-based WECS.

Background:

Due to the variation in wind speed, the power generated by wind turbines is inconsistent.
The power generated and the losses in wind turbines change correspondingly with changes
in wind speed. The only type of machine that can generate power at speeds below the fixed speed is
the doubly-fed induction generator (DFIG). But DFIG is oversensitive to network faults, which makes
the bidirectional converters and DC link capacitor fail due to high inrush current and over-voltage.

Methods:

The converters connected to DFIG consist of an AC-to-DC converter, a boost converter,
and a space vector pulse width modulation (SVPWM)-based DC-AC converter. The performance of
the SVPWM controller is analyzed during symmetrical and unsymmetrical fault conditions.

Results:

The anticipated control provides adequate reactive power support to the network through
the time of the fault and improves voltage and current waveform. The reactive power flow is also analyzed,
and the effectiveness of the proposed controller is verified using MATLAB and Simulink.

Conclusion:

SVPWM (Space Vector Pulse Width Modulation)-based inverter control is an effective
technique for wind energy conversion systems (WECS). The use of SVPWM can provide accurate
and precise control of the AC voltage generated from the DC voltage source, resulting in improved
system efficiency and reduced harmonic distortion in the output waveform.

:

The comparative analysis of THD suggests that SVPWM is a superior technique compared to other
inverter control techniques such as sine-triangle pulse width modulation (SPWM) and carrier-based
pulse width modulation (CPWM). SVPWM can help to reduce the distortion in the output waveform,
leading to improved system efficiency, reduced wear on the system components, and overall
better performance of the WECS. Furthermore, SVPWM offers several advantages over other inverter
control techniques, including better utilization of DC voltage, improved voltage control, and
better utilization of switching devices. These advantages make SVPWM a valuable tool for optimizing
the operation of WECS and improving the reliability and performance of renewable energy systems.
The value of THD for SVPWM inverter control in WECS is 1.53 under symmetrical fault and
1.34 for unsymmetrical fault, respectively. In summary, the use of SVPWM-based inverter control for
WECS is an effective way to improve the efficiency and performance of the system while reducing the
distortion in the output waveform and providing adequate reactive power support. The advantages of
SVPWM over other inverter control techniques make it a valuable tool for the development and optimization
of renewable energy systems.