Staggered Motor Coil Windings for Lower Mutual Inductance Loss

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Solution Overview

Problem

Existing motor coil structures experience large energy losses and poor performance due to mutual inductance effects between phase coils, which impede current ripple control and increase impedance.

Innovation Solution

The motor coil is designed with x sets of windings, where each set includes m-phase windings with n coil branches, connected in a staggered configuration to reduce mutual inductance by forming electrical angles of 360 degrees and P * (360 * k + 360/m) degrees, enhancing inductance and reducing energy losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a motor coil structure with phase coils is used to drive the motor, then the motor can be driven, but mutual inductance effect is generated between phase coils, impeding control of current ripples and increasing energy losses

Engineering Contradiction:
Improveenergy lossesVSAvoidcontrol of current ripples
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The motor coil is divided into multiple independent winding sets (first winding set, second winding set, etc.), each with its own phase windings and coil branches. This segmentation reduces the mutual inductance effect between phase coils by spatially separating the windings, thereby improving current ripple control and reducing energy losses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new spatial dimension by arranging coil branches at specific electrical angles (360 degrees and P*(360*k + 360/m) degrees). This dimensional arrangement in the electrical angle space reduces the coupling between phase coils, effectively mitigating the mutual inductance effect while maintaining motor drive capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If phase coils are connected with driving circuit to enable motor operation, then motor driving is achieved, but impedance control is affected and working performance is reduced

Engineering Contradiction:
Improveworking performanceVSAvoidmotor coil structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Different winding sets are configured with specific local characteristics, including designated phase windings and coil branches arranged at particular electrical angles. This local quality differentiation allows each winding set to contribute differently to the overall motor performance, improving working performance while managing structural complexity through functional specialization.

Inventive Principle:
Principle #3Local quality

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

This configuration effectively reduces energy losses and improves control of current ripples, addressing the impedance issues in motor coil performance.

Implementation Method 1

a motor coil in a motor is generally formed by a plurality of phase coils... when a current passes through the motor coil, a mutual inductance effect is generated between the phase coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

when a current passes through the motor coil, a mutual inductance effect is generated between the phase coils, impeding control of the current ripples

Methodology Applied
Scientific EffectMutual inductance: Electromagnetic Induction

Data Source

PatentEP4016806B1Motor and energy conversion device thereof
Publication Date: 2023.11.22 BYD CO LTD
  • EP4016806B1 patent drawingFigure 1~2
  • EP4016806B1 patent drawingFigure 3~5
  • EP4016806B1 patent drawingFigure 6~7

AI summary

The disclosure relates to the field of electronic technologies, and provides a motor and an energy conversion device therefor. The motor includes a motor coil. The motor coil includes x sets of windings. A number of phases of the x sets of windings is mx. In each of the x sets of windings, each phase winding includes nx coil branches. A first end of each of the nx coil branches of each phase winding is connected with a first end of a coil branch separated from the coil branch by an electrical angle of 360 degrees, to form mx phase endpoints. A second end of each of the nx coil branches of each phase winding is further connected with a second end of a coil branch separated from the coil branch by an electrical angle of P ∗ (360 ∗ k1 + 360/mx) degrees to form nx neutral points, nx ≥ mx ≥ 2, nx ≥ 3, p = ± 1, 1 ≤ k1 ≤ (nx-1), and mx nx, and k1 are all integers.