Rotary Motor Coil Connection Layout for Circulating Current Suppression
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Solution Overview
Problem
In electrical rotating machines with coils inserted in three circumferentially consecutive slots, existing methods fail to suppress circulating currents effectively, leading to reactive power losses and reduced motor output.
Innovation Solution
A wire connection method where coil segments are strategically inserted into slots with specific pitch differences to ensure equalization of coil segments across phases, using two types of coil segments with different straddle widths to form overlapping groups, allowing for balanced electrical connections and reduced circulating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If coil segments are inserted into three circumferentially consecutive slots, then the coil structure can accommodate various slot and pole combinations, but circulating currents occur causing reactive power losses and reduced motor output
Solution Approach 1:
The coil segments are divided into different types (first type with pitch of three slots, second type with pitch of four slots, third type with pitch of five slots) and strategically assigned to different slot groups. This segmentation allows each type to handle specific slot configurations, achieving balanced parallel circuits across various slot and pole combinations while preventing circulating currents.
Solution Approach 2:
Different slot groups receive different types of coil segments based on their specific positions and requirements. For example, in a 54-slot machine, slot groups are selectively assigned first type, second type, or third type coil segments depending on the local phase difference requirements, ensuring each local area contributes to overall circuit balance.
2Reliability
If the number of coil segments in each slot is unequal, then the parallel circuits lack equivalence, but increasing coil segments to balance circuits increases device complexity
Solution Approach 1:
The invention changes the pitch parameter of coil segments (three slots, four slots, or five slots) to adjust the number of coil segments in each slot. By selecting appropriate pitch values for different slot configurations, the system achieves equal coil segment distribution and parallel circuit equivalence without requiring complex additional components or structures.
3Loss of energy
If circulating currents are suppressed by equalizing coil segments, then reactive power losses are reduced, but the wire connection method becomes more complex
Solution Approach 1:
The invention performs preliminary classification of coil segments into different types with predetermined pitch values before assembly. This pre-organization allows for systematic insertion into corresponding slot groups, simplifying the manufacturing process compared to ad-hoc balancing methods, while ensuring circulating current suppression through equalized coil segment distribution.
Data Source
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Figure 3A~3B
AI summary
Coil segments of the same phase are inserted into each group of circumferentially consecutive three slots. Assuming that the grouped three slots are A, B, and C, and six groups are U1 to U6, respectively, and that slot y of group Ux are slot Uxy, a coil starting from the slot U1A is wired to pass through one turn of a stator in the order of slots U1A → U2B → U3B → U4C → U5C → U6A, and connected to slot U1A of the next turn. In this turn, coil segments with a wide straddle width are used for the connections of U1A → U2B and U3B → U4C, and a coil segment with a narrow straddle width is used for the connection of U5C → U6A. Thus, in the case of forming an electrical rotating machine in which coil segments of same phase are inserted into each three circumferentially consecutive slots, circulating current can be suppressed.