Abstract

This paper presents a control strategy for power management with maximum power extraction of a stand-alone wind-driven Permanent Magnet Synchronous Generator (PMSG). The main objective of the presented control strategy is to manage the generated wind-power between the load and the employed battery-bank in addition to extract the maximum wind-power and supply the load with a constant voltage and frequency. The wind generating-system under study consists of a wind turbine, PMSG, switch-mode rectifier (three-phase uncontrolled rectifier followed by DC-DC boost converter), bidirectional DC-DC converter, battery bank, three-phase SPWM inverter, LC filter, three-phase isolating transformer, main load and two auxiliary-loads. The proposed power-management strategy depends upon the level of the generated wind-power compared to the load power and the state of charge (SOC) level of the battery bank. The duty cycle of the DC-DC boost converter, included in the switch mode rectifier, is controlled in order to extract maximum wind-power under different operating conditions. Hence, the operating mode (charging or discharging of the battery bank) of the bidirectional DC-DC converter is controlled in order to attain an appropriate constant dc-voltage under different loading conditions. Finally, a sinusoidal pulse width modulated (SPWM) inverter is used to regulate the magnitude and frequency of the load voltage via controlling the modulation index. In order to check the validity and capability of the presented control strategy, a sample of simulation results is obtained and analyzed for the employed wind generating-system under different operating modes. The presented simulation results confirm the effectiveness of the presented control strategy to extract the maximum power from the wind and manage the active-power between the loads at a constant level of voltage and frequency.