In the last two decades, the linear permanent magnet (PM) machines which could directly realize linear movement without any additional transmission mechanisms converting the rotary motion into linear motion, are applied in direct-drive wave energy conversion (WEC) [1-4]. In particular, a conventional linear permanent magnet generator (CLPMG) reciprocates at such low-speed wave motions and...
Homopolar synchronous machine (HSM) has a solid rotor with no permanent magnet, winding and any other components. Therefore, the HSM has the merits of high speed operation, high energy storage density, brushless excitation, reliable structure, etc. However, when the HSM is analyzed and optimized by finite element analysis (FEA), the 3-D magnetic flux distribution in the HSM leads to the great...
This paper presents core loss analysis of 5kW permanent magnet linear synchronous generator (PMLSG) with slotless stator. PMLSGs are widely used in various applications. Due to the advantages of high efficiency, high power density, and low maintenance cost. Moreover, slotless stator has the advantages of reducing the detent force and magnets barely impact the electrical steel’s saturation due...
The direct-drive wave energy converter (DD-WEC) system, using linear generator, are widely used for WEC. However, at the low direct-drive speed, how to increase the power density of the linear generator is the main objective of the researchers. Therefore, there are many linear generators have been investigated for DD-WEC. To solve the problem, a transverse flux hybrid field modulated linear...
Marine currents are more predictable than wind and solar power. Because there are only small fluctuations in current speed and stream location with minimal changes in direction, ocean currents may be suitable locations for deploying energy extraction devices such as turbines. The kinetic energy of marine currents can be converted in much the same way that a wind turbine extracts energy from...
Recently, MgB2 wire and YBCO wire have been widely used in superconducting generators. However, they have differences in terms of material characteristics, product performance, price, and the relevant cryogenic cooling system, which have a great influence on the design of superconducting generators. Therefore, it is necessary to compare which wire is better for superconducting wind turbine...
High temperature superconducting (HTS) generator is attractively researched with the advantages of high efficiency, and small size compared with conventional generator. One of the big challenge is cooling down the temperature of HTS magnet to ensure the superconducting state. It can take a long time to reach a vacuum because of bulky cooling system. In order to improve the cooling performance...
Number of offshore wind farms is still increasing all over the world. The offshore wind power is greater than that on land. In addition there is no restriction of site and road for construction. However the offshore wind farm is expensive. Therefore the capacity in electricity per a wind turbine needs to be much larger than those on land and onshore. Especially, in Japan, there is so little...
Ocean wave energy has a higher energy density than other renewable resources such as solar, wind, and tide energy. In recent years, a various ocean wave energy extraction systems have been proposed and established. But the average speed of ocean wave is generally slow. This will lead the traditional linear generator with disadvantages of large weight and low power density. In order to solve...
There are two ways to maximize the electric power extracted from a Wave Energy Converter(WEC): The first is a passive method through the design of the buoy shape and the next is an active method by controlling the phenomenon that occurs when a Power Take Off(PTO) device extracts maximum electric power. The former method does not have a considerable degree of freedom and has several practical...
To avoid the mechanical wear, machine noise and improve the service life of the conventional permanent magnet synchronous generator (PMSG), a bearingless PMSG (BPMSG) is proposed in this paper. The novel BPMSG which integrated the advantages of the conventional PMSG and magnetic bearings has a wider range of application in aeronautics and astronautics, national defense, new energy, and etc.....
With the energy crisis and environmental problems becoming increasingly prominent, the utilization of renewable energy is showing an accelerated attention. Compared with wind and solar power, ocean wave energy has many advantages such as high energy density, large amount and being easy to forecast. Direct-drive ocean waves energy conversion system(WEC) has a simple structure and higher...
The floating wind power generation is an important trend of the wind power generation on the sea, paid more attentions by the researchers around the world. The direct-drive vertical axis wind turbines (DVAWT) gives an important development direction for the floating wind power generation. In order to improve the starting performance and output power of the DVAWT, a hybrid excitation maglev...
With the rapid develop of energy crisis and environmental problems, the utilization of renewable energy is attracting an increasing attention in the world. Compared with the wind and solar power, ocean wave energy has many advantages, such as high energy density, large amount and being easy to forecast, etc. Therefore, a various ocean wave energy extraction systems have been proposed and...