# Suppression of Cross-Coupling Effect of Hybrid Permanent Magnet Synchronous Motor with Parallel Magnetic Circuit

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Motor Topology

## 3. Analysis of Equivalent Magnetic Circuit and Magnetic Modulation

#### 3.1. Equivalent Magnetic Circuit Model

#### 3.2. Principle of Parallel Magnetic Circuit Magnetic Adjustment

## 4. Methods to Reduce the Cross-Coupling Effect

#### 4.1. Lengthening the Magnetic Barrier between Two Kinds of Permanent Magnets

#### 4.2. Setting the Excitation Coil Close to the Low-Coercive Permanent Magnet

## 5. Electromagnetic Analysis and Verification

#### 5.1. Lengthened Magnetic Barrier

#### 5.1.1. No-Load Analysis

#### 5.1.2. Load Analysis

#### 5.2. Adding the Excitation Winding

#### 5.2.1. No-Load Analysis

#### 5.2.2. Load Analysis

## 6. Conclusions and Shortcomings

- (1)
- When setting the magnetic barrier, the original magnetic circuit and the magnetic barrier of the high-coercive permanent magnet should be avoided.
- (2)
- Since the excitation winding is placed on the rotor, it must be equipped with a commutation device. Moreover, the additional loss and heat dissipation of the winding must be considered.
- (3)
- The two methods inevitably lead to the complex structure of the motor, which is not easy to process.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Renyuan, T. Theory and Design of Modern Permanent Magnet Motor; Machine Industry Press: Shenyang, China, 2016. [Google Scholar]
- Ostovic, V. Memory Motors—A New Class of Controllable Flux PM Machines for a True Wide Speed Operation. In Proceedings of the 36th Industry Applications Conference, Chicago, IL, USA, 30 September–4 October 2021; IEEE: Piscataway, NJ, USA, 2001. [Google Scholar]
- Limsuwan, N.; Kato, T.; Akatsu, K.; Lorenz, R.D. Design and Evaluation of a Variable-Flux Flux-Intensifying Interior Permanent-Magnet Machine. IEEE Trans. Ind. Appl.
**2015**, 50, 1015–1024. [Google Scholar] [CrossRef] - Jianzhong, S.; Fengxian, B. New Concept Permanent Magnet Machine—On the Design of Memory Machine. Large Electr. Mach. Hydraul. Turbine
**2004**, 3, 9–12. (In Chinese) [Google Scholar] - Lee, J.H.; Hong, J.P. Permanent Magnet Demagnetization Characteristic Analysis of a Variable Flux Memory Motor Using Coupled Preisach Modeling and FEM. IEEE Trans. Magn.
**2008**, 44, 1550–1553. [Google Scholar] [CrossRef] - Sakai, K.; Yuki, K.; Hashiba, Y.; Takahashi, N.; Yasui, K. Principle of the Variable-Magnetic-Force Memory Motor. In Proceedings of the International Conference on Electrical Machines & Systems, Tokyo, Japan, 15–18 November 2009; IEEE: Piscataway, NJ, USA, 2010. [Google Scholar]
- Hui, Y.; Lin, H.; Zhu, Z.Q.; Fang, S.; Huang, Y. Novel Flux-Regulatable Dual-Magnet Vernier Memory Machines for Electric Vehicle Propulsion. IEEE Trans. Appl. Supercond.
**2014**, 24, 1–5. [Google Scholar] - Yubin, Z.; Yangsheng, C.; Jianxin, S. Design of a hybrid permanent-magnet memory machine. Trans. China Electrotech. Soc.
**2015**, 30, 51–60. [Google Scholar] - Yubin, Z.; Yangsheng, C.; Jianxin, S. Analysis and improvement of a hybrid permanent-magnet memory machine. IEEE Trans. Energy Convers.
**2016**, 31, 915–923. [Google Scholar] - Hua, H.; Zhu, Z.Q.; Pride, A.; Deodhar, R.; Sasaki, T. Comparative Study on Variable Flux Memory Machines with Parallel or Series Hybrid Magnets. IEEE Trans. Ind. Appl.
**2019**, 55, 1408–1419. [Google Scholar] [CrossRef] - Wu, D.; Zhu, Z.Q.; Sasaki, T.; Liu, X.; Pride, A.; Deodhar, R.; Sasaki, T. Cross Coupling Effect in Hybrid Magnet Memory Motor. In Proceedings of the 7th IET International Conference on Power Electronics, Manchester, UK, 8–10 April 2014; IET: London, UK, 2014. [Google Scholar]

**Figure 2.**Equivalent magnetic circuits. (

**a**) Forward parallel equivalent magnetic circuit; (

**b**) reverse parallel equivalent magnetic circuit.

**Figure 3.**Illustration of flux-regulation mechanism of the parallel hybrid permanent magnet magnetic circuit.

**Figure 6.**Equivalent magnetic circuit with excitation magnetomotive force. (

**a**) Forward parallel equivalent magnetic circuit; (

**b**) reverse parallel equivalent magnetic circuit.

**Figure 7.**Distribution of magnetic lines with different lengths of magnetic barriers under the no load operation. (

**a**) a = 5 mm; (

**b**) a = 7 mm; (

**c**) a = 10 mm; (

**d**) a = 13 mm.

**Figure 8.**Back EMF with different lengths of magnetic barriers. (

**a**) Back EMF waveform; (

**b**) harmonic spectra.

**Figure 10.**Air gap flux density with different barrier lengths. (

**a**) Waveform of air gap flux density; (

**b**) spectrum analysis.

**Figure 11.**Distribution of magnetic lines with different lengths of magnetic barriers under the no load operation. (

**a**) a = 5, (

**b**) a = 7, (

**c**) a = 10, (

**d**) a = 13.

**Figure 12.**Air gap flux density with different lengths of magnetic barriers. (

**a**) Waveform of air gap flux density; (

**b**) harmonic spectra.

**Figure 14.**Back EMF with different lengths of magnetic barriers. (

**a**) Waveform of back EMF; (

**b**) harmonic spectra.

**Figure 15.**Motor output torque. (

**a**) Output torque with the forward parallel permanent magnet; (

**b**) output torque with the forward parallel permanent magnet.

**Figure 18.**Air gap flux density of the motor under different excitation currents. (

**a**) Waveform of air gap flux density; (

**b**) harmonic spectra.

**Figure 19.**Flux density of VPM under different excitation currents when the permanent magnets are reverse parallel.

**Figure 22.**Motor output torque. (

**a**) Output torque with the forward parallel permanent magnet; (

**b**) Output torque with the reverse parallel permanent magnet.

Parameters | Values | Parameters | Values |
---|---|---|---|

Phases number | 3 | CPM thickness (mm) | 6.5 |

Stator slots/rotor poles | 48/8 | CPM width (mm) | 25 |

Axial length (mm) | 50.8 | VPM thickness (mm) | 7 |

Stator outer diameter | 264 | VPM width (mm) | 25 |

Stator inner diameter | 161.9 | Number of turns per coil | 11 |

Rotor outer diameter | 160.44 | Air-gap length (mm) | 0.73 |

Rotor inner diameter | 68 | Rated speed (rpm) | 1500 |

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

He, X.; Bao, G.
Suppression of Cross-Coupling Effect of Hybrid Permanent Magnet Synchronous Motor with Parallel Magnetic Circuit. *World Electr. Veh. J.* **2022**, *13*, 11.
https://doi.org/10.3390/wevj13010011

**AMA Style**

He X, Bao G.
Suppression of Cross-Coupling Effect of Hybrid Permanent Magnet Synchronous Motor with Parallel Magnetic Circuit. *World Electric Vehicle Journal*. 2022; 13(1):11.
https://doi.org/10.3390/wevj13010011

**Chicago/Turabian Style**

He, Xiao, and Guangqing Bao.
2022. "Suppression of Cross-Coupling Effect of Hybrid Permanent Magnet Synchronous Motor with Parallel Magnetic Circuit" *World Electric Vehicle Journal* 13, no. 1: 11.
https://doi.org/10.3390/wevj13010011