A systemic design methodology of PM generators for fixed-pitch marine current turbines

Abstract

This paper deals with the systemic design of permanent magnet (PM) generator associated with fixed-pitch turbine for tidal energy generation. The main problem with marine current turbines systems are the maintenance requirements of the drive-train. It is known that the blade pitch system increases the complexity, cost, and the maintenance requirements of the drive-train. In offshore energy generation, the maintenance should be minimized as much as possible. For that purpose direct-drive permanent-magnet machines associated with fixed-pitch marine turbines can be an attractive solution. The main challenge with fixed-pitch blades is to ensure the power limitation of the turbine at high speed without using variable pitch system. As solution, we propose a systemic design approach of the generator that takes into account the power limitation requirement. In addition, this methodology takes into account the tidal site energy potential, the turbine characteristic, the control strategy, the generator specifications and the power converter constraints. The obtained results show the feasibility of our approach to satisfy the control strategy requirements.

Design Optimization of a Direct-Drive Electrically Excited Synchronous Generator for Tidal Wave Energy

“…It is als great interest to take into account the control strategy by optimizing the current and v age parameters according to variable operating points. Whereas conventional solut prefer synchronous permanent magnet machines [9,10], the use of Electrically Exc Synchronous Generators remains an interesting solution. The removal of magnets f electrical machines is actually increasingly investigated in order to free themselves f In the specific case of tidal turbines, the main challenge of the designer is to size the electrical generator considering the working cycle while managing all the constraints, especially the thermal one because the machine never operates in a steady state.…”

“…It is also of great interest to take into account the control strategy by optimizing the current and voltage parameters according to variable operating points. Whereas conventional solutions prefer synchronous permanent magnet machines [9,10], the use of Electrically Excited Synchronous Generators remains an interesting solution. The removal of magnets from electrical machines is actually increasingly investigated in order to free themselves from their excessive and highly fluctuating cost and the risks of supply disruption in a very tight market [11,12].…”

Lifetime Analysis of IGBT Power Modules in Passively Cooled Tidal Turbine Converters

“…The speed is controlled by using the active speed stall control instead of the pitch control [40][41][42]. Whereas, pitch control is common for turbines with larger power ratings (≥1 MW), for low power tidal turbines (≤300 kW) it is more common having fixed pitch blades or operating pitch control only when the tides change direction.…”

Large direct drive generators: the induction machine as an alternative to permanent magnet machines

“…6 shows assumed relationship when the tidal speed 2.75 m/s was assigned to the rated turbine speed of 15 rpm (TSR 15 ) and when the tidal speed 2.75 m/s was mapped to the rated turbine speed of 25 rpm (TSR 25 ). C p was determined from (7) [13], obtained by fitting the curve of the data from a tidal turbine prototype and is shown in Fig. 7.…”