Non-Linear Control System for Wind Power Plant with DFIG

Abstract

Nowadays actual scientific problem of renewable energy is the problem of developing control systems, that ensure the generation of stable voltage in a changing environment. This paper presents a structure and methods of synthesis of control system development, which allow to decide the indicated problem. An electric subsystem of wind power plant is a well-known structure with well-known advantages, consisting mainly of double-fed induction generator (DFIG) and power converter in the circuit of rotor. Operation of the control system based on the original nonlinear mathematical model of DFIG in rotational "dq" coordinates, taking into account the nonlinear external and internal DFIG disturbances, such as inductances of coil winding, changes of coil winding resistances from temperature, etc. The study received adaptive control algorithms of the wind turbine output voltage parameters.

Computer Simulation of Adaptive Control Algorithms for AC Wind Turbine with DFIG

“…The solution of the indicated problem, offered in this paper, is based on the nonlinear model of DFIG in rotational "dq" coordinates, as in the conditions of different disturbances, linearizing appears uneffective [1]. Because, coming from the structure of WPP, control circuit is a rotor circuit, then primary control objective is feed on it control voltage of some parameters, at that DFIG output voltage remains unchanging and corresponds to set, without depending on influences.…”

“…In detail, mathematical derivation of control laws see in [1]. So, in accordance with [1], we will get: V set through Park-Gorev transformations from "abc" coordinates to "dq".…”

“…So, in accordance with [1], we will get: V set through Park-Gorev transformations from "abc" coordinates to "dq".…”

“…Now, in accordance with [2], we will execute a procedure of synthesis for and disturbances observer, influencing on currents in stator windings, because from their values depends the value of DFIG output voltage. In detail, mathematical derivation of observer equalizations see in [1]. Now we can define equalization of observer :…”

The system of nonlinear adaptive control for wind turbine with DFIG

“…To perform full-scale simulation of the above described control system on the existing equipment is not possible, mainly due to the lack of three-phase inverter, controlled on channels of frequency and amplitude. Its replacement by the synchronous generator, even with the possibility of automatic regulation of shaft rotation frequency and voltage excitation will not be equivalent [12].…”