Hybrid control of DFIGs for short‐term and long‐term frequency regulation support in power systems

Abstract

This paper proposes a new hybrid frequency control strategy for doubly fed induction generator (DFIG)-based wind turbines (WTs) to simultaneously provide short-term and long-term frequency regulation support to the connected power system. The kinetic energy stored in the rotating mass and the mechanical power reserve of the WT are coordinately configured to participate in frequency recovery at both primary and secondary stages. A frequency response model (FRM) is also derived to analyse the mutual interactions between WTs and the power system. Based on the FRM, the impacts of relevant parameter variations on the overall system stability can be investigated through Nyquist criterion and modal analyses and the stable operation range of proposed strategy could be easily identified. Theoretical and numerical results have both verified the effectiveness of the proposed control strategy and its advantages over existing methods.

Direct slip angle control for rotor side converter of standalone DFIG‐DC system

“…Various control schemes have been proposed for the DFIG-AC [16][17][18][19][20] and DFIG-DC systems [21][22][23][24][25]. As mentioned, the grid-tied DFIG-based researches are few.…”

“…To concurrently achieve short‐term and long‐term frequency adjustment, a hybrid frequency control method for DFIG‐based wind turbines (WTs) is proposed in [17]. An optimization‐enabled wide‐area damping control for DFIG is described in [18] to diminish the oscillations of the local and inter‐area. Moreover, techniques like vector control (VC), direct power control (DPC), and direct torque control (DTC) were thoroughly analyzed for the DFIG system [20].…”

Closed‐loop fast primary frequency‐response of type‐3 wind power plants in low inertia grids

“…These methods mimic the inertial and droop response of the conventional SGs, by adding an auxiliary loop to the power controller of the WTGs. The synthetic inertial control methods are classified as the frequency deviation-based methods [8][9][10][11][12][13][14][15][16][17][18] and step over-production methods [19][20][21][22][23][24][25][26]. The frequency deviation-based methods employ a feedback loop with a constant or adaptive gain [11,12] to compensate for the power mismatch.…”

“…Various synthetic inertial control methods have been presented in [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] to exploit the kinetic energy stored in the masses of blades and gearbox stages of wind-turbines, to improve the inertial response while they operate in Maximum Power Point Tracking (MPPT) mode. These methods mimic the inertial and droop response of the conventional SGs, by adding an auxiliary loop to the power controller of the WTGs.…”

Advantages of variable‐speed pumped storage plants in generating phase‐modulation mode: rapidity and stability

“…The increasing penetration rate of renewable energies (such as wind power and solar energy) will produce a passive influence on the safe and stable operation of power system because of the features of randomness, intermittency and volatility [1–3]. As a result, it is of great significance to depress oscillations of frequency and retain active and reactive power balance in the power system effectively and efficiently [4, 5].…”