Case Studies Yaw Drive: the orientation system of the nacelle in a wind turbine.

Yaw Drive: the orientation system of the nacelle in a wind turbine.

Optimize the extraction of electricity from the wind with our customized solution.

The challenge

To develop the right motor to orient the turbine’s nacelle according to the wind and maximize the electrical energy extraction.

Yaw Drive is the orientation system of the nacelle, that is the central body of the wind turbine, and is positioned according to the direction of the wind in order to make the most of its kinetic potential. A Yaw Drive system uses several motors that move the cogwheel gear of the positioning system.

The challenge is to develop high-performance motors, with compact size and weight, particularly robust and equipped with a high degree of protection against corrosion, to withstand the aggressive outdoor environments typical of this application. The high reliability of the motor is essential to minimize maintenance interventions, which are particularly difficult and expensive, for example for offshore installations. The electrical design must be studied to overcome a wide range of voltages and above all to absorb the typical variations of this application that in the long term can damage the mechanics, insulation and functionality of the motor itself.

The development

The motors of a Yaw Drive are coupled to the respective gearboxes that act on the gear wheel on which the nacelle rests and allows the correct orientation to optimize the energy extraction from the wind. They must be high-performance motors, with reduced weight and size, to minimize the overall weight of the structure and therefore facilitate its handling and installation. At the same time, they must be robust solutions that can withstand the infinite stresses deriving from the wind, e.g. vibrations.

The Wind sector is particularly growing for our business because we have been able to understand the needs of the application, offering customizable solutions depending on the installation environment, the compactness and the necessary power

Andrea Silvestrini
Applications Sales Manager

Brake

To maximize the exploitation of the wind kinetic energy, the nacelle, once it reaches the optimal orientation, must remain locked in that position counteracting the thrust of the wind. The motor must therefore be equipped with a parking brake that maintains the reached position.

Special protection against aggressive environments

Wind turbines, whether installed in offshore or onshore environments, require special corrosion protection to withstand the aggressive outdoor environments in which they are installed. The normal protective solutions for applications in extreme environments already developed for the more standard product ranges are not enough.

The solution includes a special combination of materials, treatments (e.g. aluminum anodizing) and painting, able to guarantee the level of corrosion protection required by the application, both for the motor body and for the brake.

Irregular power supply

The supply voltage of the support systems inside the wind turbine is often not stable, but characterized by very wide variations, outside the normal tolerances acceptable by an electric motor. These variations can compromise the functionality of the motor, e.g. the activation and deactivation of the brake, but also affect the life of the motor, in particular at the level of electrical insulation.

The electrical design must therefore allow the motor to exceed a wide range of voltages and guarantee a long-life cycle to the product.

Lafert's solution

We have developed a range of brake motors, each coupled to the respective gearbox positioned on the main gear of the nacelle. The solutions include motors from size 90 to 132, equipped with AC or DC brake with specific braking torque, to maintain positioning and counteract wind thrust.

The high quality and reliability of all components and the final motor minimize production and maintenance downtime. Our motors comply with the quality standards defined by the APQP4Wind methodology, to which the main players in the wind sector adhere.

Yaw Drive application motors achieve high efficiency up to IE5 degree thanks to the PM permanent magnet technology controlled by inverters that ensures precise positioning of the nacelle. The solution is particularly suitable for offshore turbines thanks to the high torque density that allows to reduce the weight inside the nacelles, compared to the equivalent asynchronous solution.

The possibility to control the motor via inverter allows you to adjust accelerations and braking and limit the wear of the system, in particular of the brake.

Both the permanent magnet and asynchronous version consists of brake motors, equipped with direct or alternating current brake, designed in front or rear position to facilitate assembly on the specific application, as well as subsequent maintenance. The special electric design of the motor allows you to cover the wide voltage range and fluctuations typical of the application wind turbine.

The corrosion protection concerns both the choice of materials, e.g. stainless steel for braking elements and the painting of internal and external components in order to achieve a level of corrosion protection up to C5M - High (ISO 12944, salt spray).

Motor’s specifications

AC or PM brake motors
Frame size: 90 – 100 – 112 – 132
AC or DC brake with high corrosion resistance (stainless steel components, e.g. brake disc)
Specific braking torque to maintain the positioning of the nacelle by counteracting the action of the wind
Special windings to accommodate a wide range of supply voltages, typical of wind application
Efficiency up to IE5 with PM technology controlled by inverter for precise positioning (via encoder/resolver), lower stress in starting and stopping and above all reduction of weight and dimensions (essential for the installation of the nacelle, increasingly large and heavy)
Internal and external corrosion protection up to C5M-High level (ISO 12944, salt spray)
Flexibility in the assembly and positioning of components (e.g. flange, brake) to meet the installation and maintenance constraints inside the nacelle.
Direct supply motor + brake power supply through dedicated connectors
Compliance with APQP4Wind standards.

The future

We develop and supply innovative solutions for Yaw Drive, Pitch Drive, lifting systems and all auxiliary systems of a wind turbine. The next step is to supply a wind turbine entirely with our electric motors.

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