Siti Khalidah Rahimi

Design investigation of hybrid excitation flux switching machine for high-speed electric vehicles

Permanent magnet (PM) and field excitation coil (FEC) in Hybrid Excitation machine (HEMs) act as a main flux sources which has numerous attractive features compared to interior permanent magnet synchronous machines (IPMSM) usually employed in hybrid electric vehicles (HEVs). The advantage of both permanent magnet and field excitation coil located on the stator is robust rotor structure alike with switch reluctance machine (SRM). Furthermore, this machine becoming more attractive because of variable flux control capabilities from FEC, which is appropriate to be applied for high-speed motor drive systems. This HEM can be categorized as hybrid excitation flux switching machine (HEFSM). In this paper, a novel 12Slot-10Pole HEFSM in which the FEC is wounded in radial direction on the stator is proposed for traction drives in HEVs. The design target of maximum torque and power are 303Nm and 123kW, respectively. Moreover, maximum power density of more than 3.5kW/kg is to be achieved, resulting that proposed motor have better power density compared to existing IPMSM. Deterministic design optimization technique based on 2D-FEA is used to treat design parameters defined in rotor, armature coil slot and FEC slot until the target performances are achieved, under maximum current density condition for both armature coil and FEC. The final results prove that the final design HEFSM is able to keep the equivalent torque density in existing IPMSM installed on commercial HEV.

Analysis of Permanent Magnet Demagnetization Effect Outer-rotor Hybrid Excitation Flux Switching Motor

This paper addresses the irreversible permanent magnet (PM) demagnetization analysis of hybrid excitation flux switching motor (HEFSM) with outer-rotor configuration. PM demagnetization cause the PM strength used in the motor significantly reduces and hence contributes less torque performance. The study is focused on thermal analysis and conducted at various temperature up to as high as 180 degrees Celsius which has a tendency to be demagnetized. Therefore, PM demagnetization is among a critical issue and influences the choice of the applied motor. The analysis is carried out based on finite element method (FEM) and percentage of PM demagnetization is then calculated. Finally, based on simulated and calculated results the final design outer-rotor HEFSM has only 0.85 percent PM demagnetization at very high temperature and obviously the is no PM demagnetization at normal operating conditions. Full Text: PDF DOI: http://dx.doi.org/10.11591/ijpeds.v8.i1.pp255-261

Design and Improvement of 12S-14P Hybrid Excitation Flux Switching Machine with Field Excitation Coil in Radial Direction

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.

Performance Analysis of 12S-10P HEFSM with Various Flux Bridges

Flux switching machine (FSMs) with several advantages of robust rotor structure, high reliability, high efficiency and high torque density have been develop in recent years. Among several types of FSM, HEFSM gives extra advantage at variable flux capabilities suitable for higher load conditions. However, the developed C-Type has a problem of separated stator core which lead to difficulty in manufacturing design as well as flux leakage to the outer stator. In order to solve the problem, iron flux bridges have been introduced to the stator core. Because of that, the separated stator core becomes the single piece of core. In this paper, various topologies of iron flux bridges is introduced and overviewed. Performances of torque at various flux bridge is analyzed and compared. This analysis is verified by Finite Element Analysis (2D-FEA).