Time scale analysis and control of Wind Energy Conversion Systems

Abstract

This paper presents a control method to design loworder optimal controllers for a high-order Wind Energy Conversion Systems (WECS) with Permanent Magnet Synchronous Generators (PMSG). Based on the nature of the WECS which consists of different time-scale (slow and fast) dynamics, the WECS is decoupled into slow and fast subsystems using timescale analysis. Separate low-order optimal controllers are then designed for the slow and fast subsystems based on the Linear Quadratic Regulator (LQR) theory. The reduced-order optimal control of separate subsystems is compared with the high-order optimal control of the original system to show the superiority of the proposed method in terms of separation of dynamics and reduced computational effort.

Nonlinear, optimal control of wind energy conversion systems using differential SDRE

“…Although a WECS involves many different devices, these devices can be grouped as functional blocks with respect to power flow as shown in Fig. 1 [29]. The aerodynamics block converts the power from wind into mechanical power (rotations) and these rotations are increased and transmitted to the generator block by the drive train block.…”

Robust Control of Wind Turbines by Using Singular Perturbation Method and Linear Parameter Varying Model

“…Wind energy has become one of the fastest-growing energies during the last two decades [1][2][3]. Because the wind turbines are large, flexible structures operating in noisy environment can offer abundant energy to mankind, and control problems are necessary to be studied to improve the reliability and conversion efficiency of the wind energy conversion systems (WECS).…”

“…Even though a wind energy conversion system can operate over a wide range of wind speeds, basically it is only active in two regions including partial load and full load [2]. In the partial load region, the control objective is to track the desired rotor speed corresponding to varying wind speed ( ) and maintain optimal tip-speed ratio [2,6].…”

“…In the partial load region, the control objective is to track the desired rotor speed corresponding to varying wind speed ( ) and maintain optimal tip-speed ratio [2,6]. In the full load region, the generation goal is to limit the generated power to avoid overloading [4,7].…”

“…As known to all, the wind conversion systems include mechanical part and electromagnetic part, and the time scales of mechanical dynamics (slow) and electrical dynamics (fast) are quite different from each other [2,19]. So the wind conversion systems have two-time-scale property, which means these kinds of systems have high dimension and stiffness problems.…”