# Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Principle of MRC-WPT

_{1}and C

_{1}are the inductor and capacitor on the primary side, respectively. R

_{1}is the parasitic resistance on the primary side. L

_{2}and C

_{2}are the inductor and capacitor on the secondary side, respectively. R

_{2}and R

_{L}are the parasitic and load resistances on the primary side, respectively. M is the mutual inductance of primary and secondary coils. I

_{1}and I

_{2}are the currents on the primary and secondary sides, respectively. The primary side and the secondary side are isolated from each other in space, and there is no contact. Coupling is achieved by mutual inductance between the primary side and secondary side coils.

_{2}is much smaller than R

_{L}, so

## 3. A Resonant Wireless Excitation System of EESM

#### 3.1. The Type of Primary and Secondary Coils

#### 3.2. The Secondary Circuit

#### 3.3. The Voltage at the Primary Side

#### 3.4. Rotor Excitation Current Regulation

## 4. Model of EESM and RFOC

#### 4.1. Model of EESM

_{s}and R

_{f}are the stator and rotor winding resistances, respectively; i

_{d}and i

_{q}are the current components of the stator on the d-axis and q-axis, respectively; i

_{f}is the rotor excitation current; ${\psi}_{\mathrm{d}}$ and ${\psi}_{\mathrm{q}}$ are the flux components of the stator on the d-axis and q-axis, respectively; ${\psi}_{{}_{\mathrm{f}}}$ is the rotor flux; and ${\omega}_{\mathrm{r}}$ is the electrical angular velocity of the rotor.

_{d}and L

_{q}are the inductance components of the stator on the d-axis and q-axis, respectively. L

_{f}is the self inductance of the rotor. L

_{md}is the mutual inductance on the d-axis.

_{0}is the pole number of the motor. From Equations (11) and (12):

_{s}and the d-axis is defined as the torque angle β, as shown in Figure 4.

#### 4.2. RFOC

#### 4.3. Stator Current Distribution Strategy

#### 4.3.1. Maximum Torque per Ampere (MTPA) Control at Low Speed

_{e}takes the maximum value:

#### 4.3.2. Maximum Torque Control under Voltage Limitation

_{q}can be solved, and then the maximum torque control curve under voltage limitation can be obtained.

#### 4.3.3. Stator Current Distribution Strategy

_{1}. Due to the inverter voltage limitation, the motor speed cannot continue to rise.

_{1}point along the current limit circle until the current distribution point reaches the A

_{2}point on the MTPV curve. In this process, the motor speed increases and the torque decreases.

## 5. Prototype Verification Test

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

- Zhang, F.; Li, Y.; Wang, X. The design and FEA of brushless doubly-fed machine with hybrid rotor. In Proceedings of the 2009 International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2009, Chengdu, China, 25–27 September 2009; IEEE: Piscataway, NJ, USA, 2009. 5306627. pp. 324–327. [Google Scholar]
- Xia, Y.; Huang, S. Influence of field current pulsation on no-load voltage waveform of armature windings. Electr. Mach. Contrl.
**2012**, 16, 21–25. [Google Scholar] - Liu, Y.; Pehrman, D.; Lykartsis, O.; Tang, J.; Liu, T. High frequency exciter of electrically excited synchronous motors for vehicle applications. In Proceedings of the 2016 22nd International Conference on Electrical Machines, ICEM 2016, Lausanne, Switzerland, 4–7 September 2016; IEEE: Piscataway, NJ, USA, 2016. 7732554. pp. 378–383. [Google Scholar]
- Tang, J.; Liu, Y. Design and Experimental Verification of a 48 v 20 kW Electrically Excited Synchronous Machine for Mild Hybrid Vehicles. In Proceedings of the 2018 23rd International Conference on Electrical Machines, ICEM 2018, Alexandroupoli, Greece, 3–6 September 2018; IEEE: Piscataway, NJ, USA, 2018. 8507259. pp. 649–655. [Google Scholar]
- Tang, J.; Liu, Y.; Rastogi, Y.; Sharma, N.; Shukla, T. Study of Voltage Spikes and Temperature Rise in Power Module Based Integrated Converter for 48 V 20 kW Electrically Excited Synchronous Machines. In Proceedings of the 2018 IEEE Applied Power Electronics Conference and Exposition, APEC 2018, San Antonio, TX, USA, 4–8 March 2018; IEEE: Piscataway, NJ, USA, 2018. 8341011. pp. 210–217. [Google Scholar]
- Tang, J.; Liu, Y. Comparison of copper loss minimization and field current minimization for Electrically Excited Synchronous Motor in mild hybrid drives. In Proceedings of the 2017 19th European Conference on Power Electronics and Applications, EPE 2017 ECCE Europe, Warsaw, Poland, 11–14 September 2017; IEEE: Piscataway, NJ, USA, 2017. 8099352. pp. 1–10. [Google Scholar]
- Hu, K.; Deng, X.; He, F. Design and analysis of novel structural brushless electrically excited synchronous motor. Electr. Mach. Contrl.
**2014**, 18, 86–91. [Google Scholar] - Ludois, D.C.; Hanson, K.; Reed, J.K. Capacitive power transfer for slip ring replacement in wound field synchronous machines. In Proceedings of the 2011 IEEE Energy Conversion Congress and Exposition, ECCE 2011, Phoenix, AZ, USA, 17–22 September 2011; IEEE: Piscataway, NJ, USA, 2011. 6063982. pp. 1664–1669. [Google Scholar]
- Ludois, D.C.; Reed, J.K.; Hanson, K. Capacitive Power Transfer for Rotor Field Current in Synchronous Machines. IEEE Trans. Power Electron.
**2012**, 27, 4638–4645. [Google Scholar] [CrossRef] - Dai, J.; Hagen, S.; Ludois, D.C.; Brown, I.P. Synchronous Generator Brushless Field Excitation and Voltage Regulation via Capacitive Coupling through Journal Bearings. IEEE Trans. Ind. Appl.
**2017**, 53, 3317–3326. [Google Scholar] [CrossRef] - Dai, J.; Hagen, S.; Ludois, D.C.; Brown, I.P. Synchronous generator field excitation via capacitive coupling through a journal bearing. In Proceedings of the 2016 IEEE Energy Conversion Congress and Exposition, ECCE 2016, Milwaukee, WI, USA, 18–22 September 2016; IEEE: Piscataway, NJ, USA, 2016. 7855488. pp. 1–8. [Google Scholar]
- Kurs, A.; Karalis, A.; Moffatt, R.; Joannopoulos, J.D.; Fisher, P.; Soljacic, M. Wireless power transfer via strongly coupled magnetic resonances. Science
**2007**, 317, 83–86. [Google Scholar] [CrossRef] [PubMed] - Jiang, C.; Chau, K.T.; Ching, T.W.; Liu, C.; Han, W. Time-Division Multiplexing Wireless Power Transfer for Separately Excited DC Motor Drives. IEEE Trans. Magnetics
**2017**, 53, 1–5. [Google Scholar] [CrossRef] - Ditze, S.; Endruschat, A.; Schriefer, T.; Rosskopf, A.; Heckel, T. Inductive power transfer system with a rotary transformer for contactless energy transfer on rotating applications. In Proceedings of the 2016 IEEE International Symposium on Circuits and Systems, ISCAS 2016, Montreal, QC, Canada, 22–25 May 2016; IEEE: Piscataway, NJ, USA, 2016. 7538876. pp. 1622–1625. [Google Scholar]

**Figure 2.**A resonant wireless excitation system of the electrically excited synchronous motor (EESM).

Item | Parameter |
---|---|

Transfer power | Peak 160 W |

Power supply voltage | 30 V |

Load resistance | 10 Ω |

Self inductance | 25 uH |

Mutual inductance | 18 uH |

Resonant capacitance | 100 nF |

Resonant frequency | 100 kHz |

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## Share and Cite

**MDPI and ACS Style**

Bao, Y.; Zhong, Z.; Hu, C.; Qin, Y.
Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor. *World Electr. Veh. J.* **2019**, *10*, 62.
https://doi.org/10.3390/wevj10040062

**AMA Style**

Bao Y, Zhong Z, Hu C, Qin Y.
Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor. *World Electric Vehicle Journal*. 2019; 10(4):62.
https://doi.org/10.3390/wevj10040062

**Chicago/Turabian Style**

Bao, Yong, Zaimin Zhong, Chengyu Hu, and Yijin Qin.
2019. "Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor" *World Electric Vehicle Journal* 10, no. 4: 62.
https://doi.org/10.3390/wevj10040062