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

Abstract

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.

An Analysis of Iron Flux Bridges Topologies for 12Slot-14Pole HE-FSM

“…Lastly, the armature coil parameter such as armature coil width and armature coil depth, L7 and L8, are set to 6.46mm and 26. 775mm, respectively, this gives the 7 number of turns for armature coil [3]. Besides, in 2D-Finite Element Analysis (FEA) analysis, JMAG-Designer ver.14.1, released by Japanese Research Institute (JRI) is used for this design.…”

“…As for HE-FSM, it require flux source from the PM and FEC, respectively as their main flux sources [3]. PM-FSM exhibit a high torque density and high efficiency meanwhile the price of PM material is high.…”

“…2(a) and Fig. 2(b), respectively [3]. In this paper, performance analysis is carried out for numerous iron flux bridges topologies of 12Slot-14Pole HE-FSM with DC FEC in radial polarity.…”

Flux‐Switching Machines

“…The iron bridges can be used to connect the separate U-shaped laminations, which also contribute to better flux regulation performance (32). Then, as shown in Figure 15b, a new topology is proposed by employing nonoverlapping field and armature windings (33,34), as well as outer rotor type (35). However, the outer diameter of the machine is significantly enlarged for the field winding, which consequently reduces torque density.…”

Performance Analysis of 12Slot with Various Rotor Pole Numbers HE-FSM for HEV Application

“…Since HE-FSM used a hybrid excitation flux source, the machine has a potential to produce a higher torque output and power density, improve flux weakening performance, increase efficiency and more flux variable capability. It have been studied by most researcher broadly over a decade [8][9][10][11][12][13]. Figure 2 illustrates several HE-FSMs topologies that have been designed.…”