Wind turbines

Onshore

XE- and XD onshore series

Darwind’s parent company XEMC has been producing onshore direct drive wind turbines since they acquired the Z72 direct drive technology in 2006. The Z72 was rebranded, improved and today over 1500 onshore XE-series Direct Drive wind turbines have been delivered by XEMC Windpower. 

Supply chain

The original Dutch designed turbine was fitted with European components. Nowadays the turbines still use components supplied by those western companies, some of which have establishments in China. XEMC has been producing electrical equipment since 1936. XEMC’s generator company produces the permanent magnet generators for the western and Asian market.

 

XE93 2MW

XE93 2MW

The XE93 2MW is at this time the smallest turbine in the Darwind product portfolio. Its 93m rotor and compact design make it possible to install the turbine in remote areas. The turbine has proven itself over the years in the harsh environmental conditions of Inner Mongolia. To September 2013 approximately 500 turbines of the XE93 product family have been installed. The XE93 is suitable for IEC class IIIA locations.

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XD115 4,5MW

XD115 4,5MW

The XD115 onshore 4,5MW turbine is derived from the offshore dedicated 5MW. This turbine clearly benefits from its offshore predecessor. The focus is still on fast installation and low maintenance. 


Supply chain management

Darwind uses the philosophy of horizontal integration what means all manufacturing is outsourced and we only assemble and test before sending the turbine to site. All design work however is done in house and in conjunction with strategic suppliers for components such as blades, bearings, hydraulic systems, towers and pitch system. In this sense we are a system integrator although the majority of the components are of exclusive design.  

Patents

All intellectual property rights of the XD115 turbine are vested in XEMC Darwind B.V. (Netherlands). To date no license rights have been granted to third parties. To protect XEMC Darwind’s unique position over 20 patents are pending.  

XEMC Wind turbine technologies

XEMC turbines are based upon the single bearing, direct drive, and permanent magnet principle.  

XD115  

XD115  

Structural design  

Use is made of a single multiple row roller bearing on which the hub is mounted on one side and generator carrier and –rotor on the other side. The stator is mounted on the opposite side of the carrier which in turn is mounted on a compact casted nacelle frame. The advantage of this design is the relative big diameter the load path follows, contrary to the traditional designs with a main shaft. Hence considerable weight reduction is achieved.  

Light weight

Innovative design and new materials have resulted in an easy to install, large, lightweight turbines.  

Direct Drive

Our product platform is based on the direct drive principle, thereby dispensing of the need for gearboxes. Gearboxes pose a significant problem for offshore wind turbines because the torque of multi-megawatt wind turbines is enormous. In contrast, gearless turbines require less maintenance, are more reliable and therefore boast higher operating availability.

The rotor speed during power production is variable. The matching between the available aerodynamic torque and the produced electromechanical torque of the generator is determining the rotor speed. No use of a gearbox is made. The torque-speed curve is programmed in the frequency converter controller and the inverter is adapting the generator stator current in response to the measured generator power frequency.  

Single main bearing & generator in one

The XEMC Darwind XD and XE platform is based on the single main bearing concept. The bearing has a large diameter that enables it to bear the enormous force of the rotor: there is no central shaft. The bearing component is integrated into the generator and is possible because the turbine uses direct-drive technology. This innovative design not only creates a compact and lightweight permanent magnet direct-drive generator; it also results in significant savings in logistics, foundation and support structure costs.  

Fully sealed

The tower and nacelle of the turbine are fully sealed to keep out the salty and moist sea air. This protects our valuable components, increases operational availability and saves a great deal of maintenance.  

Permanent magnet

Coil driven generators make use of electrical excited magnets. XEMC’s Permanent Magnetic systems are lighter/compacter, more efficient and require less copper than Coil Driven generators. As no additional electricity is required to magnetise the rotor coils, there is no need for generator `brushes` to transfer this electricity. This increases both efficiency and reliability because the rotating part of the generator contains no electrical systems.  

Full power conversion

The AC-DC-AC converter, located in the bottom tower section, allows the generator to operate with a variable speed while the power is fed into the grid with a constant frequency of 50 Hz (or 60 Hz for the countries where this applies). It furthermore assures an average constant power output for wind speeds above rated. The power factor at the grid side is controllable at standstill as well as in operating mode. Above rated wind speed, the blade pitch control maintains a more or less constant rotor speed between admitted boundaries.  

Grid code flexibility / grid code compliance

XEMC wind turbines have a pitch-controlled variable speed rotor and a full power converter, capable of meeting the requirements of the most demanding grid codes, e.g. with respect to reactive power.

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Offshore

XD offshore series

Darwind’s Dutch based design team took care of the development of the XD offshore series. The initial design of the onshore Z72 and XE-series are the perfect basis for an offshore turbine. Our “less is more” philosophy shows itself in the single main bearing and direct drive technology, with one goal in mind: Reduce the Cost of Energy.

XD115 5MW

XD115 5MW

The XD115 5MW is designed with offshore application foremost in mind. As such it is the first offshore dedicated multi MW Direct Drive permanent magnet generator wind turbine, based on in-house proven technology. 


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