Electric blade pitch control
May 26, 2010 by Paul Dvorak
Filed under Drives, Wind Watch
A state-of-the art servodrive for electric pitch systems was on display at WINDPOWER 2010 in the Moog booth. The PITCHmaster II was developed for the harsh conditions prevailing in rotor hubs. It operates reliably at constant internal switch gear cabinet temperatures ranging from -22°F to 158°F.
The design features several advantages, such as a capability to withstand high mechanical loads in the rotating hub. An external connection is facilitated by means of an integrated diode for EPU and dc link circuit decoupling. No need for shielded cables for the EPU because its connection is included in the EMC concept. Accurate EPU voltage measurements reduce the number of additional components in the switchgear cabinet, thus reducing installation time and increasing reliability. An integrated acceleration sensor supplies information on rotor speed, rotor position, and vibrations. This data can be used for condition monitoring equipment. An inherently earth-fault proof brake driver allows regulating holding brakes to EPU voltage level, thus reducing the number of relevant switching devices in the switchgear cabinet. The motor software also supports control of synchronous, asynchronous, or dc motors.
Lastly, the PITCHmaster II was optimized to increase its reliable operation in harsh environments. This reduces the number of maintenance intervals which leads to higher wind turbine availability.
Moog acquires servodrives and backup power company
June 12, 2009 by Paul Dvorak
Filed under Wind Turbine Controls
Blade-pitch controls can fail in cold weather and high winds, but Moog says its Pitchmaster withstands temperatures from -22 to 158F.
After taking a 40% ownership stake in privately held LTi REEnergy GmbH last June, Moog Inc, East Aurora, NY, has acquired the remaining 60% of the Germany-based company . The deal lets Moog acquire two manufacturing and testing facilities, one in Unna, Germany and the other in Shanghai, China, along with an electric wind-turbine blade pitch control system that complements Moog’s existing pitch controls, rotor monitoring, and slip-ring products. Blade-pitch systems control rotor speed and, therefore, efficiency of wind turbines.
The LTi REEnergy products acquired by Moog include Pitchmaster servodrives, motors, emergency back-up systems, a control system, and software for remote diagnostics and back-up power. Most blade-pitch controls reside in the wind-turbine hub where temperature and motion can be extreme. If, for example, a wind turbine loses electrical power, then the blade-pitch control taps its battery power to gauge speed, adjusts the turbine’s blades, and puts the rotor into a safe operating mode to protect the entire unit from damage.
