Direct Power Control of DFIG With Constant Switching Frequency and Improved Transient Performance

Abstract

This paper proposes a new direct power control (DPC) strategy for a doubly fed induction generator (DFIG)-based wind turbine system. The required rotor control voltage, which eliminates active and reactive power errors within each fixed time period, is directly calculated based on stator flux, rotor position, and active and reactive powers and their corresponding errors.No extra power or current control loops are required, simplifying the system design, and improving transient performance. Constant converter switching frequency is achieved that eases the design of the power converter and the ac harmonic filter. Rotor voltage limit during transients is investigated, and a scheme is proposed that prioritizes the active and reactive power control such that one remains fully controlled while the error of the other is reduced. The impact of machine parameter variations on system performance is investigated and found negligible. Simulation results for a 2 MW DFIG system demonstrate the effectiveness and robustness of the proposed control strategy during variations of active and reactive power, machine parameters, and wind speed.Index Terms-Constant switching frequency, DFIG, direct power control, pulse width modulation (PWM) converter, wind energy. NOMENCLATURE θ s , θ rStator flux, rotor angles in the stationary frame. θPhase angle between the rotor and stator flux vectors. ω 1 , ω r , ω s

Sliding-Mode Control for a DFIG-Based Wind-Power Generation System with Series Grid-Side Converter under Unbalanced Grid Voltage Conditions

“…Similar to (20) The sliding-mode control of the RSC is similar to that of [26]. Based on the sliding-mode control, the RSC is used for control of the electromagnetic torque and for the stator reactive power.…”

“…Besides, the complexity of designing in these methods has been increased. In [18][19][20], Sliding-Mode Control (SMC) method has been introduced for DFIG control because of its easy implementation and robustness. SMC has been recently introduced for DFIG control connected to the ideal grid voltage because of its easy implementation and robustness [21][22][23][24].…”

Improved Direct Power Control of Shunt Active Power Filter with Minimum Reactive Power Variation and Minimum Apparent Power Variation Approaches

“…These methods have been mainly applied to grid connected PWM converter application such as PWM Rectifier [3], grid connected DC/AC inverter [10] and DFIGs [11]. However, recently their applications to Active Power Filter have also gained attention.…”

Site-specific design optimization of horizontal-axis wind turbine systems using PSO algorithm

“…Modeling of the rotor power coefficient resulting in power characteristics of WTSs and a comparison of produced energy for both types of wind turbines were given in [6]. Stability analyses and generator output voltage-power control strategies were demonstrated in [7,8].…”