Applied Mechanics and Materials Vol. 785

Abstract: This paper presents the design modeling and analysis of linear permanent magnet generator for wave energy conversion using finite element method. The time-stepping finite element technique is used to determine electromagnetic characteristics and analyze the efficiency. The main parts such as; copper loss is analyzed on the different variation of winding input excitation and the core loss is determined based on various specific loss curves data in order to analyze its effect on frequency. The influence of main dimension of stator is analyzed on electromagnetic characteristic and copper loss.

Abstract: This paper deduces from Finite-Element Analysis (FEA), the influence of leading design parameters on the performance of a novel T-shaped permanent magnet (PM), quasi-Halbach magnetized tubular linear motor. The proposed motor is designed and developed for small reciprocating applications. In order to obtain the maximum power density, a two-dimensional Finite-Element model is developed to investigate the performance of the proposed machine. The proposed T-shaped PM structure has a higher power density as compared to the conventional rectangular-shaped PM structure. The losses of the motor, such as copper loss and iron loss, as well as the efficiency, are established as functions of a set of motor leading design parameters. It is shown that the developed motor produce satisfactory output power, around 85 W, which is enough to operate the direct-drive reciprocating compressor of a household refrigerator.

Abstract: Advanced monitoring system and preventive maintenance introduced on serviced transformer successfully reducing the equipment malfunction and breakdown rate. However, faults that occur and developed inside the transformer can be very unpredictable. One of the measures can be taken is to analyse the hottest spot temperature (HST) of the transformer, because high temperature will affect transformer insulation system performance and its life-span. HST distribution study on the transformer surface body can give better understanding on how HST will behave at inner and outer transformer surface tank, so that it can be correlated to the actual temperature inside the transformer. Therefore, this paper presents a simulation study on 100 KVA ONAN oil-filled type of distribution transformer with three types of HST intensity. Result shows that temperature distribution projectile is tending to go upwards in the insulation oil and inward into the winding. Moreover, location of HST can be identified by comparing the temperature distribution plot with and without HST.

Abstract: This paper presents a new structure of permanent magnet flux switching machine (PMFSM) with multiple different sizes of rotor pole width. A robust single piece salient rotor is used to modulate and switch the flux linkage polarity in the armature winding and become the fundamental mechanism of these types of machines. The methodology of two-dimensional (2-D) finite element analysis (FEA) is used to evaluate the electromagnetic performance of coil test including flux line distributions, three phase flux linkage, cogging torque as well as induced emf. The resulting performances are analysed based on the variety of rotor pole width to meet the requirement of direct drive propulsion of Electric Vehicles (EVs).

Abstract: Given the volatile market prices and impending reduction in fuel supplies, electric vehicles (EV) have drawn increasing attention. The electric motor in EVs is an important component because it functions as an engine during acceleration and as a generator during deceleration or braking. Energy is saved in these processes when the kinetic energy is converted into electrical energy, which is then stored in a storage system by a regenerative braking system (RBS). In terms of highly efficient performance, ideal torque and speed, high-powered density, and cost-effective maintenance, brushless DC (BLDC) motors are preferred. This paper aims to explore and propose a seamless and effective method of RBS for a BLDC motor in an EV. In braking mode, the proposed method change the motor to act as a generator even without any additional converter, ultra-capacitor, or a complex winding-changeover technique. In this mechanism, the energy flows to the DC side. By using MATLAB/SIMULINK, the BLDC motor with speed and current controller is simulated. Accordingly, in the deceleration or braking mode, the motor functions as a generator and transports the power to the DC side. The proposed model is validated in both starting or no-load and load conditions.

Abstract: This paper presents a new design modification of Hybrid Excitation Flux Switching Machine (HEFSM) in which the initial Field Excitation Coil (FEC) in theta direction is replaced with FEC in radial direction. Obviously, the new design has advantages of preventing flux cancellation between FEC and armature coil windings. With similar design restrictions and specifications of existing electric motor used in traction drive applications, initial performances of the proposed HEFSM are evaluated based on 2D-FEA. Design modification by using deterministic optimization approach is conducted in effort to achieve the optimum performances. After several cycles of iteration, the improved HEFSM with FEC in radial direction has achieved torque and power of 304.8Nm and 130kW, respectively.

Abstract: The increasing use of energy saving lamps provides additional benefits to the application of low-power low-speed self-excited induction generators resulted from capacitor motor modification. Reactive power requirement of the generator can be provided from the capacitive nature of the lamps, while at the same time it is delivering active power to loads. Any loading change will automatically increase or reduce reactive power supply to generator. Results of experiments show that low-power low-speed single-phase self-excited induction generator is more robust and suitable for this kind of loads. Generator does not lose its voltage when experiencing abrupt change of loads. This robustness makes the generator suitable for the use in low-capacity hydropower generation in remote areas being commonly not covered by national electricity grid.

Abstract: This paper presents the new design of Hybrid Excitation Flux Switching Motor (HEFSM) using segmental rotor structure. HEFSMs are those that consist all the excitation flux sources at their stator with robust rotor structure. The rotor is designed as segmental due to the reason that segmental rotor has ability to yield the magnetic path for conveying the field flux to nearby stator armature coil with respect to the rotation of the rotor. This design gives the clear advantage of shorter end winding compared to the toothed rotor as there is no overlap winding between field excitation coil (FEC) and armature coil. In this paper the initial design of HEFSM with segmental rotor has been improved by changing segment span, FEC slot area and armature slot area until maximum torque and power of 33.633 Nm and 8.17 KW respectively have been achieved. Moreover coil test analysis, induced voltage, cogging torque, magnetic flux characteristics, torque vs. field current density and torque vs. power speed characteristics are examined on the basis of 2-D finite element analysis (FEA).

Abstract: This paper will focus on designing and modelling the portable pico linear generator for the wave energy converter application. The aim for this research is to develop a permanent magnet linear generator which has the weight less than 20 kg and can produce up to 80 W. A thorough literature review has been done on type of configurations, stator structure, magnetization and type of cored to select the best features of the linear generator. Three proposed designs of the permanent magnet linear generator is presented and each of the proposed design performance is simulated using the Ansys Maxwell software. Comparison on the preliminary result such as the air gap flux distribution, back-emf, flux linkage and thrust force of the three proposed designs will be shown and discussed.

Abstract: This paper illustrates a design methodology to accomplish optimum performance for a single-phase, tubular, linear permanent magnet generator which drives linear motion of wave energy for Wave Energy Conversion (WEC) system application. It is shown that the linear generator performance can be optimized with respect to three leading dimension ratios. Existence of copper loss in the linear generator also can be reduced by performing the optimization process. Results for the linear generator efficiency, copper loss and output power are demonstrated and discussed are shown to be as expected.