# Sensitivity Analysis of a Double-Layer Coupling Structure for an Electric Vehicle Wireless Power Transfer System

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Overview of an EV WPT System

- 1.
- The system should achieve load-independent constant voltage/current output:

- 2.
- The transmitting coil should achieve load-independent constant current output:

- 3.
- The input impedance should meet the zero phase angle (ZPA) condition:

- 4.
- The number of compensating devices should be as small as possible:

_{in}is the input high-frequency AC voltage generated by the inverter; L

_{f}, C

_{f}, and C

_{P}are the series compensating inductor, parallel compensating capacitor, and series compensating capacitor, respectively, which comprise the symmetric T-type network; C

_{S}is a secondary series compensating capacitor; L

_{1}, L

_{2}, and M are the primary self-inductance, secondary self-inductance, and mutual inductance of the coupling coils, respectively; and R

_{L}is the equivalent load resistance of the receiver circuit.

## 3. Design of Coupling Structure

- 1.
- The coupling coil has a certain resistance to combined spatial motion:

- 2.
- The size of the coupling coil should be limited:

- 3.
- Electromagnetic shielding and electromagnetic compatibility should be considered:

- 4.
- The manufacturing cost of the WPT system should be considered:

#### 3.1. Parameter Optimization

_{S1}and L

_{S2}are the self-inductance of the SP at the transmitter and the receiver, respectively; L

_{D1}is the self-inductance of the DDP at the transmitter and L

_{D2}is the self-inductance of the DDP at the receiver; M

_{S1D1}is the mutual inductance between the SP and the DDP at the transmitter; M

_{S2D2}is the mutual inductance between the SP and the DDP at the receiver; M

_{S1S2}and M

_{D1D2}are the mutual inductance between the SPs and DDPs at the transmitter and the receiver, respectively; M

_{S1D2}is the mutual inductance between the transmitter SP and the receiver DDP; M

_{D1S2}is the mutual inductance between the transmitter DDP and the receiver SP; L

_{1}and L

_{2}are the self-inductance of the transmitter coil and the receiver coil, respectively; and M is the mutual inductance of the SP-DDP coupling structure. The formulas for L

_{1}, L

_{2}, and M are provided below.

- Defining the limiting conditions and optimization parameters;
- Finite element simulation and evaluation of the coil;
- Electromagnetic shielding design.

#### 3.1.1. Defining the Limiting Conditions and Optimization Parameters

_{S1}, N

_{S2}, N

_{D1}, and N

_{D2}, respectively.

#### 3.1.2. Finite Element Simulation and Evaluation of the Coil

#### 3.1.3. Electromagnetic Shielding Design

#### 3.2. Anti-Misalignment and Anti-Deflection Performance

#### 3.3. Experiment of Prototype

_{X-sim}, M

_{Y-sim}, and M

_{Z-sim}are the simulation mutual inductance of misalignment along the X-, Y-, and Z-axes as well as the deflection around the X-, Y-, and Z-axes, respectively; M

_{X-exp}, M

_{Y-exp}, and M

_{Z- exp}are the experimental mutual inductance of misalignment along the X-, Y-, and Z-axes as well as the deflection around the X-, Y-, and Z-axes, respectively.

## 4. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 5.**SP-DDP coupling structure with and without aluminum case shielding: (

**a**) no aluminum shield; (

**b**) with an aluminum shield.

**Figure 6.**The magnetic field distribution cloud figure of the SP-DDP coupling structure with and without the aluminum case shielding: (

**a**) no aluminum shielding; (

**b**) with aluminum shielding.

**Figure 7.**How misalignment and mutual inductance change the SP-DDP coupling structure: (

**a**) misalignment along the X-axis; (

**b**) misalignment along the Y-axis; (

**c**) misalignment along the Z-axis; and (

**d**) change in mutual inductance.

**Figure 8.**Figure of deflection and mutual inductance change of SP-DDP coupling structure: (

**a**) deflection around the X-axis; (

**b**) deflection around the Y-axis; (

**c**) deflection around the Z-axis; and (

**d**) change in mutual inductance.

**Figure 10.**Simulation and experimental results regarding changes in mutual inductance with misalignment and deflection of SP-DDP coupling structure: (

**a**) misalignment; (

**b**) deflection.

Parameters | Value | Parameters | Value |
---|---|---|---|

Transmitter DDP length l_{A} (mm) | 200 | Receiver DDP length l_{a} (mm) | 200 |

Transmitter DDP width l_{B} (mm) | 200 | Receiver DDP width l_{b} (mm) | 200 |

Transmitter DDP inner rectangle length l_{M} (mm) | 132.8 | Receiver DDP inner rectangle length l_{m} (mm) | 142.4 |

Transmitter DDP inner rectangle width l_{N} (mm) | 32.8 | Receiver DDP inner rectangle width l _{n} (mm) | 42.4 |

Transmitter SP length l_{P} (mm) | 207 | Receiver SP length l_{p} (mm) | 207 |

Transmitter SP width l_{Q} (mm) | 28.8 | Receiver SP width l_{q} (mm) | 28.8 |

Transmitter SP height l_{H} (mm) | 9.8 | Receiver SP height l_{h} (mm) | 9.8 |

Transmitter SP separation distance l _{C} (mm) | 71.2 | Receiver SP separation distance l _{c} (mm) | 71.2 |

Ferrite length l_{FA} (mm) | 200 | Ferrite width l_{FB} (mm) | 200 |

Ferrite height l_{FH} (mm) | 3 | Wire diameter d_{C} (mm) | 2.4 |

Parameters | With Aluminum Plate | Without Aluminum Plate |
---|---|---|

Mutual inductance | 222.49 μH | 218.67 μH |

Self-inductance of transmitter | 312.26 μH | 310.71 μH |

Self-inductance of receiver | 274.53 μH | 271.96 μH |

Weight of transmitter | 1.52 kg | 1.65 kg |

Weight of receiver | 1.47 kg | 1.56 kg |

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## Share and Cite

**MDPI and ACS Style**

Xu, F.; Wei, S.; Li, J.; Yuan, D.
Sensitivity Analysis of a Double-Layer Coupling Structure for an Electric Vehicle Wireless Power Transfer System. *World Electr. Veh. J.* **2023**, *14*, 322.
https://doi.org/10.3390/wevj14120322

**AMA Style**

Xu F, Wei S, Li J, Yuan D.
Sensitivity Analysis of a Double-Layer Coupling Structure for an Electric Vehicle Wireless Power Transfer System. *World Electric Vehicle Journal*. 2023; 14(12):322.
https://doi.org/10.3390/wevj14120322

**Chicago/Turabian Style**

Xu, Feifan, Shuguang Wei, Jiaqi Li, and Dong Yuan.
2023. "Sensitivity Analysis of a Double-Layer Coupling Structure for an Electric Vehicle Wireless Power Transfer System" *World Electric Vehicle Journal* 14, no. 12: 322.
https://doi.org/10.3390/wevj14120322