Flat Wire Motor Winding Layout for Three-Branch Current Balance

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Solution Overview

Problem

Flat copper wire drive motors in electric vehicles suffer from unbalanced current in each phase winding branch, leading to uneven heating and insulation damage due to complex structures that hinder automated production processes.

Innovation Solution

A three-branch balanced winding structure for a six-pole, fifty-four-slot flat copper wire motor with symmetrical distribution and equal spans and heights of welding ends, utilizing a Y-connection or delta-connection manner, and a six-layer winding configuration to balance current distribution and simplify production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple parallel branches are used in flat copper wire motors, then the power capacity is improved, but the structure of bridging wires, star point wires, and power supply lead wires becomes complex

Engineering Contradiction:
Improvepower capacityVSAvoidstructure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The winding is divided into six distinct layers (first layer through sixth layer) with specific wire type assignments. Each layer contains standardized wire configurations that simplify the overall structure while maintaining multiple parallel branches for high power capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent standardizes wire spans and heights across different layers. For example, U-pin wires in the second and third layers both have span of 9, and U-pin wires in the fourth and fifth layers both have span of 10. This parameter standardization simplifies production while supporting multiple parallel branches.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If complex winding structures with special-shaped wires are used, then the electrical performance is improved, but the mass production processability deteriorates

Engineering Contradiction:
Improveelectrical performanceVSAvoidmass production processability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses homogeneous wire types within each layer. The first layer contains only I-Pin and U-Pin wires, the second and third layers contain only U-pin wires with span 9, the fourth and fifth layers contain only U-pin wires with span 10, and the sixth layer contains only U-pin wires with span 11. This homogeneity enables automated production while maintaining electrical performance.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The standardized wire configurations serve multiple functions: they provide electrical connectivity, maintain structural integrity, and facilitate automated insertion. The same wire types and span parameters are reused across different layers, reducing the need for special-shaped wires while maintaining electrical performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If unbalanced current distribution occurs in parallel branches, then the motor operates, but uneven heating damages the insulation system

Engineering Contradiction:
Improvemotor operationVSAvoidinsulation system reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent balances the current distribution in parallel branches by carefully designing the winding connections. Each phase has three parallel branches with equal impedance characteristics, ensuring balanced current flow. The standardized wire spans and heights across layers contribute to equalizing the electrical path lengths and impedances, preventing uneven heating and insulation damage.

Inventive Principle:
Principle #12Equipotentiality

4Productivity

If the power supply frequency is increased, then the motor efficiency is improved, but the circulating current between parallel branches increases

Engineering Contradiction:
Improvemotor efficiencyVSAvoidcirculating current
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent optimizes wire span parameters to minimize circulating current at higher frequencies. The specific span values (9 for second/third layers, 10 for fourth/fifth layers, 11 for sixth layer) are selected to balance the inductance and resistance of parallel branches, reducing circulating current effects while maintaining motor efficiency at increased supply frequencies.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4391318B1Six-pole 54-slot flat wire motor three-branch balancing winding and use method therefor
Publication Date: 2026.03.11 GZK INTELLIGENT POWER TECH (SHANGHAI) CO LTD
  • EP4391318B1 patent drawingFigure 1
  • EP4391318B1 patent drawingFigure 2
  • EP4391318B1 patent drawingFigure 3~4

AI summary

Disclosed are a three-branch balanced winding of a six-pole, fifty-four-slot flat copper wire motor and a method. A three-branch balanced winding of a six-pole, fifty-four-slot flat copper wire motor includes a three-phase flat copper wire winding distributed symmetrically along a circumferential direction of an iron core slot. Spans of the welding end (1) are equal, and heights of the lead welding ends (1) are equal. The power lead wire end (3) is composed of four U-Pin wire types and one I-pin wire type, and a first layer of the power lead wire end (3) is composed of an I-Pin wire (4) and an U-pin wire (5) with an equal span. Both a second layer and a third layer are composed of U-pin wires (6) with an equal span. Both a fourth layer and a fifth layer are composed of U-pin wires (7) with an equal span. A sixth layer is composed of a U-pin wire (8) with an equal span.