Study on a Rotor Speed Control System for a Horizontal Axis Windmill

摘要

Rotor speed control technology in windmills is indispensable not only in attaining a high level of energy conversion but also in avoiding damage to the windmill rotor system under very strong wind conditions. This study was conducted as part of the component technology research and development program for the 20kw horizontal axis windmill system development project sponsored by the Science and Technology Agency of Japan. A hydraulic pitch control system for a 1kw class windmill (a pioneering subscale model for the 20kw windmill) was developed and improved through repeated tests in the NAL low speed wind tunnel and in field tests. The original application of the electromagnetic proportional hydro-relief valve to the hydraulic pitch control system of windmills brought an outstanding reduction of the variation in widnmill rotational speed. Test results confirm the excellent characteristics of the windmill rotor speed control. The practicality of the hydraulic pitch control system has been proving itself in the 20kw windmill operation since December 1985.