# Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor

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## Abstract

**:**

## 1. Introduction

## 2. Structure of IWM

#### 2.1. Basic Structure of IWM

#### 2.2. Basic Parameters of IWM

## 3. Analysis of Electromagnetic-Heat-Flow Coupling Factors

#### 3.1. Analysis of the Coupling Factors of Electromagnetic Field and Temperature Field

#### 3.1.1. Influence Factors of Electromagnetic Field on Temperature Field

#### (1) Core Loss

^{−13}W, the value of the additional core loss is so small that it is almost negligible; ${B}_{m}$ is the amplitude of the flux density, $T$; $f$ is the magnetic field frequency, $Hz$; $\alpha $ is the empirical coefficient, and the general value is 2; $\sigma $ is the conductivity, $S/m$; $d$ is the thickness of silicon steel sheet, $mm$.

#### (2) Eddy Current Loss of the PM

#### (3) Copper Loss

#### 3.1.2. Influence of Temperature Field on Electromagnetic Field

#### (1) Influence of Temperature on the Conductivity of Materials

#### (2) Influence of Temperature on Residual Flux Density of PM

#### 3.2. Analysis of the Coupling Factors of Temperature Field and Flow Field

#### 3.2.1. Influence of Temperature on Thermal Conductivity of Fluid

#### 3.2.2. Influence of Temperature on the Specific Heat Capacity of Fluid

#### 3.2.3. Influence of Temperature on the Dynamic Viscosity of Fluid

^{2}and a distance of 1 m, when relative motion is at a speed of 1 m/s, and internal friction is caused by the interaction of fluids. The calculation formula is as follows [26]:

#### 3.2.4. Influence of Temperature on the Density of Fluid

#### 3.3. Analysis of the Coupling Factors of Electromagnetic Field and Flow Field

## 4. The Establishment of Electromagnetic-Fluid-Thermal Coupling Model for IWM and Model Validity Verification

#### 4.1. The Establishment of the Finite Element Model of IWM

#### 4.2. Determination of Boundary Conditions and Material Properties of IWM

#### 4.2.1. Determination of Material Properties of IWM

#### 4.2.2. Determination of Boundary Conditions of IWM

#### 4.3. Grid Division of IWM

#### 4.4. Model Validity Verification

#### 4.5. Three-Field Coupling Calculation Method

## 5. Analysis of Electromagnetic-Heat-Flow Coupling, Based on Working Conditions

#### 5.1. Comparison and Analysis of the Simulation Results of Unidirectional Coupling and Bidirectional Coupling

#### 5.2. Vehicle Working Condition Setting

#### 5.3. Analysis of Electromagnetic Field Simulation Results of IWM

#### 5.4. Analysis of Temperature Field Simulation Results of IWM

#### 5.5. Analysis of Flow Field Simulation Results of IWM

#### 5.6. Variation of Maximum Temperature of IWM at Different Flow Rates

## 6. Results

## Author Contributions

## Funding

## Conflicts of Interest

## References

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Name | Numerical Value | Name | Numerical Value |
---|---|---|---|

Stator outer diameter | 310 mm | Rotor inner diameter | 200 mm |

Stator inner diameter | 240 mm | Air gap length | 0.9 mm |

Stator length | 69 mm | Rotor length | 71 mm |

Diameter of inlet and outlet | 15 mm | Rib width | 4 mm |

Channel cross section | 232 mm^{2} | Channel height | 10 mm |

Name | Numerical Value | Name | Numerical Value |
---|---|---|---|

Rated power | 15 KW | Speak speed | 1100 rpm |

Peak power | 54 KW | Rated speed | 1000 rpm |

Component | Material | Thermal Conductivity $(\mathit{W}/\left(\mathit{m}\xb7\mathit{K}\right))$ | Density $(\mathit{k}\mathit{g}/{\mathit{m}}^{3})$ | Specific Heat Capacity $(\mathit{J}/\left(\mathit{K}\mathit{g}\xb7\mathit{K}\right))$ |
---|---|---|---|---|

Stator and rotor core | DW465-50 | 40/40/0.95 | 7700 | 426 |

Winding | copper | 379 | 8900 | 390 |

PM | NdFeB | 6.16 | 7800 | 460 |

Insulation layer | Insulation material | 0.3 | 1300 | 1340 |

Housing | 45 steel | 50.2 | 7850 | 480 |

Air | Air | 0.0267 | 1.29 | 1000 |

Maximum Temperature (°C) | ||||
---|---|---|---|---|

Stator Core | Rotor Core | Winding | PM | |

electromagnetic-heat-flow | 54.2 | 52.7 | 57.6 | 51.3 |

flow-heat | 50.1 | 47.1 | 53 | 46.2 |

Maximum Temperature (°C) | ||||
---|---|---|---|---|

Stator Core | Rotor Core | Winding | PM | |

flow-heat coupling factors | 54.2 | 52.7 | 57.6 | 51.3 |

without fluid-heat coupling factors | 52.1 | 50.7 | 55.1 | 50.2 |

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**MDPI and ACS Style**

Xue, H.; Tan, D.; Liu, S.; Yuan, M.; Zhao, C.
Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor. *World Electr. Veh. J.* **2020**, *11*, 29.
https://doi.org/10.3390/wevj11020029

**AMA Style**

Xue H, Tan D, Liu S, Yuan M, Zhao C.
Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor. *World Electric Vehicle Journal*. 2020; 11(2):29.
https://doi.org/10.3390/wevj11020029

**Chicago/Turabian Style**

Xue, Haojie, Di Tan, Shuaishuai Liu, Meng Yuan, and Chunming Zhao.
2020. "Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor" *World Electric Vehicle Journal* 11, no. 2: 29.
https://doi.org/10.3390/wevj11020029