# Slot Design Optimization for Copper Losses Reduction in Electric Machines for High Speed Applications

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## Abstract

**:**

## 1. Introduction

## 2. Analytical Approach

## 3. Finite Element Analyses

#### 3.1. Introduction to the Analyses

- The percentage reduction, or the increment, in the total power losses;
- The percentage difference between the greatest and the smallest impedance $\Delta Z\%$ between the conductors inside the slot, see Equation (13).$$\Delta Z\%=\frac{{Z}_{max}-{Z}_{min}}{{Z}_{min}}$$

#### 3.2. Slot Opening Width Analysis

#### 3.2.1. Rectangular Slot

#### 3.2.2. Trapezoidal Slot

#### 3.3. Tooth Width Analysis

#### Trapezoidal Slot

#### 3.4. Polar Shoe Depths Analysis

#### Trapezoidal Slot

#### 3.5. Slot Depth to Width Ratio Analysis

^{2}was imposed and only the rectangular shape were considered.

#### Rectangular Slot

## 4. Conclusions

- Narrow stator teeth;
- Great polar shoes, in order to create the best flux density paths;
- Narrow slot-opening.

## Author Contributions

## Funding

## Conflicts of Interest

## Abbreviations

BEV | Battery Electric Vehicles |

HEV | Hybrid Electric Vehicles |

FEA | Finite Element Analysis |

KPI | Key Performance Indicator |

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## Share and Cite

**MDPI and ACS Style**

Bianchini, C.; Vogni, M.; Torreggiani, A.; Nuzzo, S.; Barater, D.; Franceschini, G.
Slot Design Optimization for Copper Losses Reduction in Electric Machines for High Speed Applications. *Appl. Sci.* **2020**, *10*, 7425.
https://doi.org/10.3390/app10217425

**AMA Style**

Bianchini C, Vogni M, Torreggiani A, Nuzzo S, Barater D, Franceschini G.
Slot Design Optimization for Copper Losses Reduction in Electric Machines for High Speed Applications. *Applied Sciences*. 2020; 10(21):7425.
https://doi.org/10.3390/app10217425

**Chicago/Turabian Style**

Bianchini, Claudio, Mattia Vogni, Ambra Torreggiani, Stefano Nuzzo, Davide Barater, and Giovanni Franceschini.
2020. "Slot Design Optimization for Copper Losses Reduction in Electric Machines for High Speed Applications" *Applied Sciences* 10, no. 21: 7425.
https://doi.org/10.3390/app10217425