# Wireless Charging Concave Coil Design for UAVs

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## Abstract

**:**

## 1. Introduction

## 2. Concave Coupling Mechanism Design

#### 2.1. Wireless Charging Coupling Mechanism for Drones

#### 2.2. Design of Coupling Mechanism Dimensions

#### 2.3. Coupling Structure Optimization

#### 2.4. Magnetic Field Distribution of the Coupling Mechanism

#### 2.5. Coupling Mechanism Anti−Offset Test

## 3. System Circuit and Control Design

#### 3.1. The Double-Sided LCC Compensation Topology Analysis

#### 3.2. Closed-loop Control System Design

## 4. System Construction and Experiment

## 5. Discussion

## 6. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 10.**(

**a**) Variation of coupling coefficients for different L1 lateral offsets. (

**b**) Variation of coupling coefficients at different L1 longitudinal offsets. (

**c**) Variation of coupling coefficients for different W1 lateral offsets. (

**d**) Variation of coupling coefficients at different W1 longitudinal offsets. (

**e**) Variation of coupling coefficients for different H1 lateral offsets. (

**f**) Variation of coupling coefficients at different H1 longitudinal offsets.

**Figure 11.**(

**a**) Distribution of magnetic flux lines in the transmitting coil (

**b**) Flux line distribution in the receiving coil.

**Figure 12.**(

**a**) Magnetic field distribution during alignment of concave structures. (

**b**) Magnetic field distribution during the offset of the concave structure.

**Figure 13.**(

**a**) Variation of coupling coefficients for offset in the X−axis direction. (

**b**) Variation of coupling coefficients for offset in the Y−axis direction.

**Figure 14.**(

**a**) Variation of the original side self-inductance. (

**b**) Variation of the secondary side self-inductance.

**Figure 19.**Rated power test for the 2.4 Ω fixed resistive load. (

**a**) DC-input and charging output power. (

**b**) System Loss Analysis. (

**c**) Inverter working waveform.

**Figure 20.**Charging voltage and current versus load resistance. (

**a**) Change the load resistance from 1.5 Ω to 48 Ω. (

**b**) Change the load resistance from 1.5 Ω to 5.5 Ω.

**Figure 21.**Charging power and system efficiency versus (

**a**) lateral displacement and (

**b**) longitudinal displacement.

Parameters | Values (mm) | Parameters | Values (mm) |
---|---|---|---|

Length of transmitting coil L1 | 305 | Launch core length L2 | 240 |

Width of transmitting coil W4 | 190 | Receiving coil length L3 | 294 |

Emission core width W2 Core width W3 | 120 28 | Receiving coil height H1 Receiving coil width W5 | 130 3.65 |

Symbol | Value | Symbol | Value |
---|---|---|---|

$\mathrm{Input}\mathrm{voltage}{\mathit{U}}_{\mathit{i}\mathit{n}}$ | $136V$ | $\mathrm{Primary}\mathrm{side}\mathrm{series}\mathrm{capacitance}{C}_{1}$ | 45 nF |

$\mathrm{Inductance}\mathrm{of}\mathrm{Transmitting}\mathrm{coil}{\mathit{L}}_{\mathit{1}}$ | $90.5\mathsf{\mu}\mathrm{H}$ | $\mathrm{Primary}\mathrm{side}\mathrm{shunt}\mathrm{capacitance}{C}_{f1}$ | 275 nF |

$\mathrm{Inductance}\mathrm{of}\mathrm{receiving}\mathrm{coil}{\mathit{L}}_{\mathit{2}}$ | $18.8\mathsf{\mu}\mathrm{H}$ | $\mathrm{Sec}\mathrm{ondary}\mathrm{side}\mathrm{series}\mathrm{capacitance}{C}_{2}$ | 336 nF |

$\mathrm{Primary}\mathrm{side}\mathrm{compensates}\mathrm{inductance}{\mathit{L}}_{\mathit{f}\mathit{1}}$ $\mathrm{Auxiliary}\mathrm{side}\mathrm{compensates}\mathrm{inductance}{\mathit{L}}_{\mathit{f}\mathit{2}}$ Load RL | $12.7\mathsf{\mu}\mathrm{H}$ $8.57\mathsf{\mu}\mathrm{H}$ 2.4 Ω | $\mathrm{Sec}\mathrm{ondary}\mathrm{side}\mathrm{shunt}\mathrm{capacitance}{C}_{f2}$ $\mathrm{coupling}\mathrm{coefficient}k$ Receiving coil weight | 408 nF $0.366$ 290 g |

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## Share and Cite

**MDPI and ACS Style**

Yu, L.; Wu, L.; Zhu, Y.; Cao, X.; Zhang, G.; Xiang, S.
Wireless Charging Concave Coil Design for UAVs. *Electronics* **2022**, *11*, 1962.
https://doi.org/10.3390/electronics11131962

**AMA Style**

Yu L, Wu L, Zhu Y, Cao X, Zhang G, Xiang S.
Wireless Charging Concave Coil Design for UAVs. *Electronics*. 2022; 11(13):1962.
https://doi.org/10.3390/electronics11131962

**Chicago/Turabian Style**

Yu, Langtao, Li Wu, Yuyu Zhu, Xin Cao, Guozheng Zhang, and Shicheng Xiang.
2022. "Wireless Charging Concave Coil Design for UAVs" *Electronics* 11, no. 13: 1962.
https://doi.org/10.3390/electronics11131962