Real-Time Control of Active and Reactive Power for Doubly Fed Induction Generator (DFIG)-Based Wind Energy Conversion System

Abstract

This paper presents the modeling, rapid control prototyping, and hardware-in-the-loop testing for real-time simulation and control of a grid-connected doubly fed induction generator (DFIG) in a laboratory-size wind turbine emulator for wind energy conversion systems. The generator is modeled using the direct-quadrature rotating reference frame circuit along with the aligned stator flux, and the field-oriented control approach is applied for independent control of the active and reactive power and the DC-link voltage at the grid side. The control of the active, reactive power and the DC-link voltage are performed using a back-to-back converter at sub-and super-synchronous as well as at variable speeds. The control strategy is experimentally validated on an emulated wind turbine driven by the Opal-RT real-time simulator (OP5600) for simultaneous control of the DC-link voltage, active and reactive power.

Real-time implementation of sliding-mode field-oriented control for a DFIG-based wind turbine

“…Wind electric generation is one of the best alternative electric energy sources because of its economic benefits and usefulness for power systems in diverse areas . For a variable speed wind turbine (WT), there are many reasons to use a DFIG, such as noise reduction, effort reductions on the WT shaft, reduced cost inverters, and the possibility for stator active and reactive powers control .…”

“…The DFIG rotor is coupled to the grid via power electronic converters (rectifier, filter, and inverter), while the DFIG stator is linked directly to the grid; this configuration allows decoupling the grid frequency from the DFIG rotational speed . In fact, a rectifier can be directly linked to the grid or via the step‐up transformer terminals, which provides a stable DC voltage in the output of grid‐side converter (GSC) . The DC‐link voltage is used as the voltage source for rotor‐side converter (RSC), which is directly coupled to the rotor winding terminals …”

“…To regulate the GSC and the RSC for a DFIG prototype, an SM block control technique is used in Sanchez and Ruiz‐Cruz . Tanvir et al present an experimental validation of a control algorithm for the WT based on DFIG, using a PI controller to regulate the RSC and a hysteresis controller for the GSC.…”

Feedback Linearization Controller for a Wind Energy Power System

“…Investigations to determine the best nonlinear control technique that can be used to improve the performance of DFIG-based WEC systems are still ongoing [29]. The control of both the grid side converter (GSC) and the rotor side converter (RCS) in one control loop was reported in [30].…”

Passivity-Based Control of a Doubly Fed Induction Generator System under Unbalanced Grid Voltage Conditions

“…The converter's capacity is relatively small and largely influenced by the status of the grid. Therefore, higher requirements are desired if DFIGs are to be constructed on a large scale and operated in grid-connected mode [6][7][8][9]. Though the PI regulator based vector control is commonly used and can ensure stable operation of DFIGs within certain range, it is not intrinsically robust, and it can be rather difficult to realize the overall stability of the system.…”