To solve the problem of the tracking speed versus control efficiency trade off problem of the hill climb search(HCS) method, an adaptive variable step search algorithm realized by fuzzy PID is applied. Based on the equivalent circuit analysis of the wind energy conversion system (WECS), a speed-sensorless control scheme has been developed. A 5kW stand alone WECS was analyzed in the Simulink. The results show that the proposed algorithm has better dynamic performance and capture more power than the conventional HCS under constant wind and variable wind.