A robust H∞ controller based frequency control approach using the wind-battery coordination strategy in a small power system

In this paper, a coordinated control method for a wind turbine generator (WTG) and a battery energy storage system (BESS) of a small power system have been presented. The coordinated control approach applies to control the system frequency to reduce the size of BESS and to control the pitch angle system to mitigate the wind turbine blades stress. To achieve these objectives simultaneously, the robust H,, control method is applied in this paper. The pitch angle system of the WTG and the output power command system of the BESS are controlled by the H-infinity controllers. The output power command of the WTG is determined from the wind velocities and it is controlled by the pitch angle control system. Concurrently, the output power command of the BESS is calculated according to the state of charge and the frequency deviations in the small power system. The small power system includes a WTG, a BESS and a diesel generator. Numerical simulations are conducted by the MATLAB/SIMULINK (R) environment to validate the proposed method. (C) 2014 Elsevier Ltd. All rights reserved.