Analytical calculation no-load air-gap flux density of air-core compensated pulsed alternator with double layer Halbach

Xue Zhiqiang; Liu Jianfeng; Jiao Chuanhai; Huang Yao

doi:10.11884/HPLPB202638.250366

Article Contents

Article Navigation > High Power Laser and Particle Beams > 2026 > Accepted Manuscript

Xue Zhiqiang, Liu Jianfeng, Jiao Chuanhai, et al. Analytical calculation no-load air-gap flux density of air-core compensated pulsed alternator with double layer Halbach[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250366

Citation:

Xue Zhiqiang, Liu Jianfeng, Jiao Chuanhai, et al. Analytical calculation no-load air-gap flux density of air-core compensated pulsed alternator with double layer Halbach[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250366

Citation:

Xue Zhiqiang, Liu Jianfeng, Jiao Chuanhai, et al. Analytical calculation no-load air-gap flux density of air-core compensated pulsed alternator with double layer Halbach[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250366

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Analytical calculation no-load air-gap flux density of air-core compensated pulsed alternator with double layer Halbach

doi: 10.11884/HPLPB202638.250366

Army Arms University of PLA, Hefei 230031, China

Received Date: 2025-10-25
Accepted Date: 2026-02-04
Rev Recd Date: 2026-02-14

Available Online: 2026-03-11

Abstract

Abstract

Background
The compensated pulsed alternator (CPA) is a pulsed power source that integrates rotor inertial energy storage, electromechanical energy conversion and power regulation. It connects the prime mover and the electromagnetic launch load directly as a “unit component”, reducing many intermediate links. It has the advantages of high output voltage, high power density, high frequency of repetition and long service life, and is regarded as the most promising pulsed power source for electromagnetic launch systems.
Purpose
The air-core CPA (ACCPA) overcomes the limitations of ferromagnetic material saturation on magnetic field strength and rotational speed, significantly improving the motor’s energy storage density and power density. The Halbach permanent magnet array (HPMA) possesses a magnetic shielding, eliminating the need for a rotor core while generating an air-gap magnetic flux density (AGMFD) waveform with good sinusoidal characteristics. Therefore, this paper investigates the application of a double-layer HPMA rotor, which is simple in structure, strong in integrity, and easy to optimize, in the topological structure of ACCPA.
Methods
Without considering magnetic saturation, an analytical calculation model for the no-load electromagnetic field in an ACCPA was established using the subdomain model method in polar coordinates. Starting from the basic theory of electromagnetic fields, this method used the vector magnetic potential method to establish Laplace’s equations (for no- curl fields) or Poisson’s equations (for curl fields) for four subdomains respectively. By combining the boundary conditions between adjacent subdomains, the equations were solved jointly to obtain the mathematical expression for the no-load AGMFD of the motor, and the distribution of the no-load AGMFD was analyzed.
Results
This analytical model could directly reflect the relationship between the no-load AGMFD distribution of the motor and its design parameters. The analytical model’s calculation results were highly consistent with the results of finite element analysis, verifying the accuracy of the analytical model. Its calculation results could relatively accurately reflect the static and steady-state performance of the motor.
Conclusions
The relationship between the four main parameters of the motor and the amplitude and sinusoidal characteristics of the radial and tangential components of the no-load AGMFD is studied, which can provide technical support for the subsequent optimization of the motor’s no-load air-gap magnetic field and further calculation design.
- compensated pulsed alternator,
- magnetic field distribution,
- double layer Halbach,
- permanent magnet array,
- analytical prediction

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References(16)

References

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