Earticle

초록

영어

This paper proposes a field current control method to improve the flux-weakening operation performance of a no-insulation (NI) high-temperature superconducting (HTS) synchronous motor for electric vehicles. An NI field coil can enhance thermal stability by providing turn-to-turn current bypass paths; however, turn-to-turn leakage current caused by contact resistance and the large electrical time constant of the coil can delay the field flux response. In particular, in the high-speed operating region of a synchronous motor, the armature d−axis current rapidly changes in the negative direction for flux-weakening control, which induces voltage and current in the field circuit. The induced current causes the azimuthal current to deviate from its reference value and increases the back-electromotive-force component, leading the armature q−axis voltage to reach the voltage limit prematurely. In this study, an analytical model combining the lumped circuit of the NI field coil and the d−q equivalent circuit of the synchronous motor is developed, and a proportional–integral (PI)-based field current controller is designed to regulate the azimuthal current. The effectiveness of the proposed control method is verified under an acceleration condition from standstill to 4000 rpm. The analysis results show that, in the maximum torque per ampere operation region, the difference in operating characteristics with and without field current control is insignificant because the variation rate of the d−axis current is limited. In contrast, in the flux-weakening region above approximately 2400 rpm, the proposed control method significantly improves the operating performance. With field current control, the maximum azimuthal current decreases from 197 A to 192 A, and the settling time of the azimuthal current to its reference value is reduced from 90 s to 9.5 s. In addition, by suppressing the increase in back electromotive force, the q−axis voltage margin is secured, and the time required to reach 4000 rpm is reduced from approximately 72 s to approximately 5 s. A comparison under different contact resistivity conditions also confirms that the proposed field current control method maintains similar acceleration performance. Furthermore, a higher contact resistivity reduces both the turn-to-turn leakage current and the variation in the field operating current. These results indicate that the proposed field current control method is effective for improving the high-speed operation performance of NI HTS synchronous motors, and that contact resistivity should be selected by considering not only acceleration performance but also leakage current, loss, and thermal stability.

목차

Abstract
1. INTRODUCTION
2. OPERATING CHARACTERISTICS OF THE NO-INSULATION HTS SYNCHRONOUS MOTOR UNDER MTPA AND FLUX-WEAKENING CONTROL
2.1. d−q equivalent circuit model of a high-temperature
2.2. Induced current characteristics of the no−insulation field coil under armature–field coupling
2.3. Dynamic characteristics of the no−insulation HTS synchronous motor under MTPA and FW operation
3. FIELD CURRENT CONTROL SCHEME OF THE NO−INSULATION FIELD COIL FOR INDUCED CURRENT COMPENSATION
3.1. Design of the PI controller for azimuthal current regulation
3.2. Validation of the proposed scheme in the MTPA and flux-weakening regions
4. DISCUSSION
5. CONCLUSION
ACKNOWLEDGMENT
REFERENCES

키워드

저자

• Hoon Jung [ Faculty of Applied Energy System Electrical Engineering, Jeju National University, Jeju, South Korea ]
• Sung Hoon Lee [ Electric Energy Research Center, Jeju National University, Jeju, South Korea ]
• Huu Luong Quach [ Faculty of Electrical Engineering, Can Tho University, Can Tho, Viet Nam ]
• Ho Min Kim [ Faculty of Applied Energy System Electrical Engineering, Jeju National University, Jeju, South Korea ] Corresponding Author
• Ji Hyung Kim [ Electric Energy Research Center, Jeju National University, Jeju, South Korea ] Corresponding Author

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  한국초전도·저온논문지 (구 한국초전도저온공학회논문지) [Progress in Superconductivity and Cryogenics]

• 간기

  계간

• pISSN

  1229-3008

• eISSN

  2287-6251

• 수록기간

  1999~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 427 DDC 537