Performance indexes’ evaluation of a NSynRM with sinusoidal rotor shape

Abstract

This study presents the evaluation of performance indexes of a novel synchronous reluctance motor (NSynRM) that has an axially sinusoidal rotor lamination shape. The stator of a 5.5 kW, 4-pole, 50 Hz conventional three-phase squirrel cage induction motor, with distributed and chorded by one slot, double-layer winding, is used for both standard and NSynRMs. Owing to the nature of the sinusoidal rotor structure, the three-dimensional finite element analysis (FEA) is utilised to study the electromagnetic parameters of interests. The NSynRM with sinusoidal rotor shape results is compared with the standard SynRM without cutoff on the q-axis. The FEA results are validated by means of practical measurements.

Line-Start Synchronous Reluctance Motor With V-Shaped Rotor Laminations

“…The torque harmonic produced by the variation of d-and q-axis inductances along the top V-shape of the rotor structure will be the same in magnitude with the harmonic torque produced in the bottom V-shape rotor structure [19]. The effect of variation of d-and q-axis inductances on the middle stack lamination can be negligible due to its no cutoff structure [19]. On the other hand, the effect on other rotor stack laminations that form the two V-shapes will be cancelled due to the opposite periodicity of the rotor structure.…”

“…1(c) and (d), it is noted that the rotor has two V-shapes per pole that are structurally opposed from one another. The torque harmonic produced by the variation of d-and q-axis inductances along the top V-shape of the rotor structure will be the same in magnitude with the harmonic torque produced in the bottom V-shape rotor structure [19]. The effect of variation of d-and q-axis inductances on the middle stack lamination can be negligible due to its no cutoff structure [19].…”

“…1(c) and (d). The total axial length of the rotor lamination is obtained using (1), and the variations of cut-off pitch and cut-off angle for a V-shape structure are expressed as shown in ( 2) and (3), respectively [17]- [19]. The subscript n represents the stack lamination number, 𝜉 𝑛 is the axial length of each n individual stack lamination shape, 𝜉 𝑣 is the axial length of the middle lamination shape, 𝑤 𝑖 is the total thickness of steel lamination insulation coating, 𝛽 𝑝 is the barrier pitch angle, ℎ 𝑏 is the barrier height, 𝑤 𝑏 is the barrier web width, 𝑏 𝑒𝑟 is the barrier end radius, 𝑏 0(1 ,2) is the barrier web length, 𝑏 𝑖(1 𝑜𝑟 2) is the barrier base length, ℎ 𝑖(1,2,3) is the iron width, 𝑙 𝑟𝑡 is the tangential bridge width, 𝑙 𝑟𝑟 is the radial bridge width, 𝑟 𝑟𝑟 is the radius of the rotor lamination, and 𝑟 𝑠ℎ is the shaft radius.…”

“…On the other hand, the effect on other rotor stack laminations that form the two V-shapes will be cancelled due to the opposite periodicity of the rotor structure. This will assist with the mitigation of torque ripple in the proposed LS-SynRM-VSRL [19]. The IE2-132S4 NEMA stator frame with three-phase winding is shown in Fig.…”

“…The above electromagnetic torque equation has two components, mainly due to induction and reluctance. In (19), ΔLmdqv and ΔLmdqn are the differences between the d-axis and q-axis magnetizing inductances for the mid-point stack lamination 𝑣 and the 𝑛 number of stack laminations, respectively. Using (17) and (18), the dynamic mechanical model of the LSSynRM with v-shape rotor laminations is given by…”