IPMSM Rotor Core Bridge Layout for Lower Torque Pulsation
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Solution Overview
Problem
There is a growing demand for techniques to reduce torque pulsation in interior permanent magnet synchronous motors (IPMSM).
Innovation Solution
A rotor core design with flux barriers and bridges is implemented, where the width of the rear bridge is greater than the front bridge, and the central locations of these bridges are positioned to optimize magnetic flux paths, minimizing torque pulsation by controlling the magnetic flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotor core design is used, then manufacturing is simpler, but torque pulsation increases
Solution Approach 1:
The rotor core is segmented into multiple functional regions: front bridges, rear bridges, front flux barriers, and rear flux barriers. Each segment serves a specific purpose in controlling magnetic flux distribution, with the front and rear bridges having different widths to independently manage flux paths at different positions, thereby reducing torque pulsation through distributed flux control
Solution Approach 2:
Different regions of the rotor core are given different properties: the front bridges have a first width while rear bridges have a second width (different from the first), allowing local optimization of magnetic flux control at different positions. This local differentiation enables precise control over flux distribution to minimize torque pulsation
2Reliability
If symmetric bridge design is used, then manufacturing is easier, but magnetic flux control is insufficient
Solution Approach 1:
The rotor core employs asymmetric design where front bridges and rear bridges have different widths. The front bridge width is set to a first value while the rear bridge width is set to a second value (different from the first), creating intentional asymmetry to optimize magnetic flux control at different positions and reduce torque pulsation
Solution Approach 2:
The design changes the geometric parameter of bridge width differently at different positions: front bridges have width W1 while rear bridges have width W2, where W1 ≠ W2. This parameter variation allows independent optimization of flux control characteristics at the front and rear of the rotor core, improving torque stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces torque pulsation by guiding magnetic flux efficiently, enhancing torque output and stability in rotary electric machines.
Implementation Method 1
A plurality of sets of permanent magnets forming magnetic poles are disposed in the rotor core in a circumferential direction of the rotor core
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A rotor core (31) includes a front bridge (37f) provided between an outer circumferential surface (31a) of the rotor core (31) and a front flux barrier (35f) and a rear bridge (37r) provided between the outer circumferential surface (31a) of the rotor core (31) and the rear flux barrier (35r). A relative location of a central location θr of the rear bridge (37r) to a rear reference location θsr of the rear flux barrier (35r) is located rotationally rearward relative to a relative location of a central location θf of the front bridge (37f) to a front reference location θsf of the front flux barrier (35f). A width Wf of the front bridge (37f) is different from a width Wr of the rear bridge (37r).