# Research on Dual-Phase Non-Salient Pole Receiver for EV Dynamic Wireless Power Transfer System

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## Abstract

**:**

## 1. Introduction

## 2. Analysis of Basic Principle

_{0}is the resonant frequency, I

_{P}is RMS current of the transmitter and k

_{dc−ac}is the gain from the average voltage of the DC side to the RMS voltage of the AC side [20].

_{AB}is the center distance between two modules. Two modules compensate each other and reduce the sensitivity of the mutual inductance to the misalignment. It is possible for mutual inductance to be unchanged within a certain range of misalignment through optimized design.

## 3. Parameter Optimization Analysis

#### 3.1. Length and Width of the Receiver Yoke

_{yoke}and widths of receiver yoke w

_{yoke}. Obviously, a larger w

_{yoke}leads to a larger end face of the coupling flux, and then, the mutual inductance and the coupling coefficient are increased. However, the influence is weakened along with a larger w

_{yoke}. In Figure 5a, l

_{yoke}has little effect on the mutual inductance of winding D; due to that, a pair of adjacent magnetic poles is mostly covered by the receiver yoke in Mode 1. However, the coupling coefficient decreases in Figure 5b with too large l

_{yoke}because it provies a leakage flux path for other magnetic poles of the transmitter. A winging Q consists of two sub windings, and the mutual inductance of each sub winding is weaker because of smaller covered area of adjacent magnetic poles by the receiver yoke in Mode 2. This also means that l

_{yoke}has a larger effect on the mutual inductance and the coupling coefficient, which are shown in Figure 5c,d. In summary, under the spacing limitation of the receiver in engineering design, the receiver yoke is preferred to be longer and narrower, to significantly improve the mutual inductance of winding Q with less sacrifice of winding D and to reduce the wire consumption under the same design requirements.

#### 3.2. Center Distance of Receiver Winding Q

_{Q}has no effect on the coupling mode of the dual-phase NSP receiver. To optimized d

_{Q}, the inner magnetic flux of the position in the receiver yoke surrounded by the winding Q should be larger when the magnetic flux is generated by only one transmitter. It is shown in Figure 6 that the optimized d

_{Q}is close to the center distance between adjacent magnetic poles τ of transmitter. It should be noticed that when d

_{Q}is 600 mm, the mutual inductance is less effected by τ, which shows possible interoperability between the dual-phase NSP receiver and different designs of the transmitter.

#### 3.3. Center Distance between Receiver Module A and B

_{AB}is shown in Figure 7. According to the principal analysis of coupling compensation by two modules in Figure 3b, it is shown that when d

_{AB}is smaller than 400 mm, it is in a compensation state, when d

_{AB}is equal to 400 mm, it is in a critical compensation state, and when d

_{AB}is larger than 400 mm, it is in an overcompensation state. In the critical compensation state, the mutual inductance is unchanged within 160 mm of misalignment, which is quite valuable for improving misalignment tolerance.

## 4. Design and Simulation Verification

## 5. Experiment

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**Overall configuration of the dual-phase NSP receiver: (

**a**) Structure of the magnetic coupler with the dual-phase NSP receiver; (

**b**) Connection of the dual-phase NSP receiver in the system.

**Figure 3.**The characteristic of mutual inductance of the dual-phase NSP receiver with (

**a**) moving distance and (

**b**) misalignment distance.

**Figure 5.**(

**a**) The mutual inductance and (

**b**) the coupling coefficient of single-turn winding D in Mode 1, and (

**c**) the mutual inductance and (

**d**) the coupling coefficient of single-turn winding Q in Mode 2.

**Figure 8.**Diagrams of (

**a**) the proposed dual-phase NSP receiver and (

**b**) the reference dual-phase DD-OQO receiver.

**Figure 9.**Simulated normalized receiving voltage of (

**a**) the proposed dual-phase NSP receiver and (

**b**) the reference dual-phase DD-OQO receiver with moving distance and misalignment distance.

**Figure 10.**Experimental system for comparing the dual-phase NSP receiver and the dual-phase DD-OQO receiver.

**Figure 12.**Power waveforms of the system with two receivers: (

**a**) the dual-phase NSP receiver; (

**b**) the dual-phase DD-OQO receiver.

**Figure 14.**Output characteristics of two receivers with different misalignments from the maximum mutual inductance position and the minimum mutual inductance position: (

**a**) the dual-phase NSP receiver; (

**b**) the dual-phase DD-OQO receiver.

Structure Parameter | Symbol | Value |
---|---|---|

Center distance between adjacent magnetic poles | τ | 600 mm |

Length of receiver yoke | l_{yoke} | 1000 mm |

Width of receiver yoke | w_{yoke} | 200 mm |

Center distance of receiver winding Q | d_{Q} | 600 mm |

Center distance between receiver module A and B | d_{AB} | 400 mm |

Type of Receiver | Dual-Phase NSP | Dual-Phase DD-OQO |
---|---|---|

Resonant frequency | 20 kHz | |

Transmission distance | 200 mm | |

Rated transmitter current | 70 A (RMS) | |

Specification of Litz wire | 0.1 mm × 2500 strands | |

Material of magnetic cores | PC95 | |

Overall area (including shielding) | 1200 mm × 800 mm | 1200 mm × 800 mm |

Size (except shielding) | 1000 mm × 220 mm × 30 mm (1 module) | 1200 mm × 800 mm × 30 mm |

Width of the receiver (except shielding) | 620 mm | 800 mm |

Number of turns | D winding: 16 turns Q winding: 14 turns | D winding: 6 turns Q winding: 7 turns O winding: 4 turns |

Length of wires | 36.96 m | 69.80 m |

Volume of magnetic cores | 4000 cm^{3} | 4800 cm^{3} |

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

Inductance of transmitter | L_{P} | 210 µH |

Inductance of dual-phase NSP receiver | L_{SDA} + L_{SDB}L _{SQA} + L_{SQB} | 236.0 µH 262.2 µH |

Inductance of dual-phase DD-OQO receiver | L_{S-DD}L _{S-OQO} | 153.7 µH 172.9 µH |

AC internal resistance of transmitter | r_{P} | 60 mΩ |

AC internal resistance of dual-phase NSP receiver | r_{SDA} + r_{SDB}r _{SQA} + r_{SQB} | 63 mΩ 78 mΩ |

AC internal resistance of dual-phase DD-OQO receiver | r_{S-DD}r _{S-OQO} | 65 mΩ 80 mΩ |

Max mutual inducatance with dual-phase NSP receiver | M_{NSP} | 16.0 µH |

Max mutual inducatance with dual-phase DD-OQO receiver | M_{DD-OQO} | 17.0 µH |

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## Share and Cite

**MDPI and ACS Style**

Zhao, F.; Jiang, J.; Cui, S.; Zhu, C.; Chan, C.C.
Research on Dual-Phase Non-Salient Pole Receiver for EV Dynamic Wireless Power Transfer System. *World Electr. Veh. J.* **2021**, *12*, 157.
https://doi.org/10.3390/wevj12030157

**AMA Style**

Zhao F, Jiang J, Cui S, Zhu C, Chan CC.
Research on Dual-Phase Non-Salient Pole Receiver for EV Dynamic Wireless Power Transfer System. *World Electric Vehicle Journal*. 2021; 12(3):157.
https://doi.org/10.3390/wevj12030157

**Chicago/Turabian Style**

Zhao, Fandan, Jinhai Jiang, Shumei Cui, Chunbo Zhu, and C. C. Chan.
2021. "Research on Dual-Phase Non-Salient Pole Receiver for EV Dynamic Wireless Power Transfer System" *World Electric Vehicle Journal* 12, no. 3: 157.
https://doi.org/10.3390/wevj12030157