28. Integrated Design Wind speed distribution Wind turbine model Generator model Axial-flux Electrical model Structural model Criterion calculation Radial-flux 5 MW 3 MW 2 MW Thermal model
29. Hydrodynamic model Generator model Electrical model Structural model Criterion calculation Thermal model Design Optimisation Final Design Wave Energy Converter Wave Frequency Distribution
34. Induction Generator Modelling for OWCs - Wavegen Airflow and generator power recorded during OWC operation Recorded casing and winding temperatures and 1 minute average generator power during operation
37. F drive F spring F drive F spring Phase 1 Spring force is less than magnetic attraction force: Translator and armature move in same direction. Phase 2 Spring force matches magnetic attraction force: Armature movement ceases Phase 3 Armature becomes decoupled from translator and begins to move at high velocity relative to the translator.
45. What type of TFPM machine ? A number of TFPM machine types have been proposed. It is necessary to find the most suitable type. How?
46. Comparative design of PM machines a) RFPM machine b) TFPM machine-1 c) TFPM machine-2 d) TFPM machine-3 e) TFPM machine-4
47. Design parameters 12 Rotational speed, rpm 3 Number of phase, m 675 A Nominal current, i s 2746 V No-load voltage, e p 6.14 mm Air gap length, l g 6.14 m Air gap diameter, D g 5.56 MW Generator power, P Generator parameter 25 Magnet cost ( € /kg) 15 Copper cost ( € /kg) 3 Laminations cost ( € /kg) Cost modeling 0.025 Resistivity of copper at operating temperature (μΩm) 1.06 Recoil permeability of the magnets 1.2 Remanent flux density of the magnets (T) Material parameter
Perhaps add in some figures on global market from Future Energy Solutions – p8
Map of UK with resource, and a summary of bullet points of technical available resource
OWC – picture and describe the main components in the system – comment on efficiency of Wells Turbine
Picture of pelamis and bullet points of power conversion – SRO contract
NEED TO GET BETTER PICTURE
Picture and info on direct drive power take off
Better picture of SEAGEN
Example of Challenge facing Direct Drive in Wave Energy
Importance of structural material: From cost and mass point of view: Electromagnetic only: Small aspect ratio; reduce magnet and copper material Electromagnetic and structural material: Increase aspect ratio – smaller diameter and longer; large radius means lots of structural material Normally have airgap length as fixed % of airgap diameter (0.1%) From cost and mass point of view: Better to have larger airgap length and allow structure to be less stiff
The structural optimization highlighted the danger in not optimizing the active and inactive material together a generator design that minimizes active mass leads to a design that maximizes inactive/structural mass. The integrated electromagnetic–structural optimization indicated that machines with a larger airgap will result in lower mass! Traditionally, the airgap is kept as small as possible to optimize the electromagnetic performance. For minimum mass, large aspect ratios (ratio of length to airgap radius) with a larger airgap is desirable, leading to a sausage shaped machine. For minimum cost, small aspect ratios or pancake machines are more desirable, because active mass decreases with radius, and this forms the most expensive part of the generator.
OWC has air-flow over generator. Air-flow assists cooling of generator - include in thermal model 16% additional power achievable without exceeding temperature limits of machine
Go through main characteristics, pros & cons
In the case of TFPM machine, a number of electromagnetic topologies have been proposed as shown in this slide. For large direct-drive wind generators, what type of TFPM machine can be the most suitable? Therefore, it is necessary to find the most suitable type. But, how?
RF machine with surface mounted PM has been discussed as a better choice for large direct-drive wind in references. Therefore, RF machine with surface mounted PM is selected as the RFPM machine for this comparative design. The flux-concentrating TFPM machine has higher force density than other topologies. The single-winding type is simple in construction. Therefore, four different flux-concentrating single-winding TFPM machines are selected for this comparative design. The selected machine types are named as this slide.
5 MW five different PM machines have been designed and compared electromagnetically in terms of mass, cost and loss. In the figure of right side, the criteria values of each concept are divided by RFPM criteria which are the copper loss, the mass/power ratio m/P , the cost/power ratio cost/P , and the cost/mass ratio Cost/m , respectively. The copper losses of TFPM machines are significantly lower than the RFPM machine. The RFPM machine is the 3rd in mass , the 2nd in cost , and the 2nd in cost/m among the five generators. TFPM machine-2, which has the double-sided air gap and single-winding with C-cores, seems the best concept considering all criteria. However, to maintain the double-sided air gap is difficult in constructing. Regarding construction, TFPM machine-1 seems a better choice than TFPM machine-2 concept. However, TFPM-1 is heavier than RFPM. Therefore, when TFPM-1 is selected, it is required to reduce the mass and cost of TFPM-1 further to overcome RFPM.
RF machine with surface mounted PM has been discussed as a better choice for large direct-drive wind in references. Therefore, RF machine with surface mounted PM is selected as the RFPM machine for this comparative design. The flux-concentrating TFPM machine has higher force density than other topologies. The single-winding type is simple in construction. Therefore, four different flux-concentrating single-winding TFPM machines are selected for this comparative design. The selected machine types are named as this slide.
16m diameter, 500kW in low tidal currents, to be installed off Northern France Airgap winding similar to Goliath Ed Spooner is the main designer of the machine
AM One of the unique features of the C-GEN is it’s modular assembly The C-GEN rotor (which is coupled to the wind turbine blades) was made from 32 C-cores; each made machined standard mild steel pieces; PMs attached and then combined to make the C-cores; and then these were then brought together with 2 aluminium discs and the rotor shaft. The stator (which carries the electrical winding) is made up of 24 coil modules; these are combined to give a complete stator
Other permanent magnet generator technologies are difficult and dangerous to assemble, because there are large forces of attraction between the rotor and stator modules. This typically requires hydraulic jacks and manpower. The C-GEN design does not have this problem, so the stator can be easily lowered into place, here by an engine hoist. Potential savings for large size, large scale production are significant. Benefit for maintenance too.
AM - The C-GEN Mk I 20kW has been built and successfully tested on the test rig at Edinburgh. We have produced high efficiencies over the whole load range and verified our initial designs.
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