VP7-01 Mechanical Flux-Weakening Design of the Bidirectional Flux-Modulated Radial Permanent Magnet Generator for Wind Power Generation
Creators: Zixu Dong
Mingyuan Jiang
Shuangxia Niu and K. T. Chau
Publisher: name: IEEE
Year: 2025

I. Introduction Nearly one-fifth of the world's population still lacks access to the grid, with many of these populations residing in remote areas where expanding the grid may not be feasible. Therefore, stand-alone wind power generation systems are highly applicable in such scenarios. Permanent magnet synchronous motor (PMSM) is widely used because of its excellent performance, but usually requires two sets of windings. In addition, in order to achieve weak magnetic and speed up, previous motors usually use electrical method, but electrical method will cause PM demagnetization and additional current consumption. This paper proposes a bidirectional flux-modulated radial permanent magnet synchronous generator (PMSG) based mechanical flux-weakening design. By implementing the flux modulation principle to achieve a mechanical flux-weakening, the risk of demagnetization of the PMs is avoided. By selecting the working harmonic, ensuring that the pole pair number of the outer rotor matches the number of stator slots, the adjustment of total back electromotive force (EMF) output can be achieved with only one set of windings, greatly reducing the manufacturing complexity of the motor. II. Proposed Motor Structure The generator topology is shown in the Fig. 1, consisting of the stator, rotor, and adjustable modulation ring. The angle of the adjustable modulation ring is controlled by an additional servo motor to achieve the purpose of controlling the magnetic flux. Both the rotor and adjustable modulation ring contain radial PMs. The number of pole pair on the adjustable modulation ring matching the number of stator slot, in order to use one set of winding to produce total back EMF. III. Performance After optimization and finite element analysis, the performance of the motor is shown. Fig. 2 shows the voltage regulation curve as the modulation ring angle changes, the voltage regulation ratio can up to 93%, which indicates a large regulation range and also indicates that the system is very suitable for the stand-alone wind power generation system
I. Introduction Nearly one-fifth of the world's population still lacks access to the grid, with many of these populations residing in remote areas where expanding the grid may not be feasible. Therefore, stand-alone wind power generation systems are highly applicable in such scenarios. Permanent magnet synchronous motor (PMSM) is widely used because of its excellent performance, but usually requires two sets of windings. In addition, in order to achieve weak magnetic and speed up, previous motors usually use electrical method, but electrical method will cause PM demagnetization and additional current consumption. This paper proposes a bidirectional flux-modulated radial permanent magnet synchronous generator (PMSG) based mechanical flux-weakening design. By implementing the flux modulation principle to achieve a mechanical flux-weakening, the risk of demagnetization of the PMs is avoided. By selecting the working harmonic, ensuring that the pole pair number of the outer rotor matches the number of stator slots, the adjustment of total back electromotive force (EMF) output can be achieved with only one set of windings, greatly reducing the manufacturing complexity of the motor. II. Proposed Motor Structure The generator topology is shown in the Fig. 1, consisting of the stator, rotor, and adjustable modulation ring. The angle of the adjustable modulation ring is controlled by an additional servo motor to achieve the purpose of controlling the magnetic flux. Both the rotor and adjustable modulation ring contain radial PMs. The number of pole pair on the adjustable modulation ring matching the number of stator slot, in order to use one set of winding to produce total back EMF. III. Performance After optimization and finite element analysis, the performance of the motor is shown. Fig. 2 shows the voltage regulation curve as the modulation ring angle changes, the voltage regulation ratio can up to 93%, which indicates a large regulation range and also indicates that the system is very suitable for the stand-alone wind power generation system