An Efficient Supervisory Power Management Scheme for a Wind–Battery-Assisted Hybrid Autonomous System

Abstract

This article presents an efficient power management and protection scheme for a wind–battery-assisted hybrid autonomous system. To operate the wind power generation system at the maximum power point (MPP), a drift-free perturb and observe algorithm is adapted. A unified controller for a bidirectional converter (BDC) is incorporated for the dc-bus voltage regulation along with the charge/discharge control of the battery. The small-signal analysis of the BDC and the buck converter is presented in detail. The performance of the proposed power management scheme (PMS) is validated through a time-domain simulation in MATLAB/Simulink along with the hardware implementation using the DS1103 digital platform. Initially, the PMS with only maximum power point tracking (MPPT) and pitch controller is unable to maintain the dc-bus voltage during the battery overcharge or deep-discharge condition. To address this issue, an <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> -MPPT controller is proposed to regulate the dc-bus voltage. The effectiveness of all the operating modes of the proposed PMS is verified in the developed laboratory prototype, and the performance is also compared with that of the classical droop control method. The experimental results confirm the ability of the PMS to handle power sharing and dc-bus voltage fluctuation during wind speed and load change and satisfy the load demand. This ensures that the improved performance of the developed hybrid autonomous system and changeover from the MPP to the generator or battery protection mode is seamless and fast.