An Improvement of Output Power in Doubly Salient Permanent Magnet Generator Using Pole Configuration Adjustment

Abstract

The doubly salient permanent magnet (DSPM) machines are very attractive for low-speed power generation. In this work, we propose a design technique to improve the output power of the DSPM generator by an adjustment of pole configuration. The number of stator and rotor poles, split ratio, as well as the stator pole arc of the generator, were proposedly adjusted and optimized. The output characteristics of the generator including the magnetic flux linkage, electromotive force, harmonic, cogging torque, electromagnetic torque, output voltage and output power were analyzed through finite element analysis. The symmetrical magnetic field distribution of all generators was firstly verified. Then, the results indicated that this particular generator was optimized at 18 stator poles and 12 rotor poles, while the split ratio and the stator pole arc should be set as 0.78 and 6.15 degrees, respectively. The proposed optimal generator could provide a significant improvement in the output voltage and the output power compared to the conventional structure. The output power of 1.28 kW can be reached by the optimal structure, which was two times higher than that of the conventional structure. The physical explanation regarding to the structural modification was also given. The proposed design technique can be applied for improving the output power of the DSPM machines.

E-Core and C-Core Switched Flux Permanent Magnet Generators for Wind Power Generation

“…Stator PM machines are particularly appealing for lowspeed wind power generation, as they typically exhibit lower inertia and higher robustness compared to rotor PM machines [5,6]. Within the category of stator PM machines, three different configurations are commonly utilized: doubly salient permanent magnet machines, flux reversal permanent magnet machines, and switched flux permanent magnet (SFPM) machines [5][6][7][8]. Of these configurations, SFPM machines have attracted significant research attention due to their potential improvements in power and torque capability, highly symmetric sinusoidal back-electromotive force (EMF), high reliability, low risk of demagnetization, and a simple structure with high robustness [9][10][11][12].…”

Design Optimization of Outer Rotor Toothed Doubly Salient Permanent Magnet Generator Using Symbiotic Organisms Search Algorithm

“…The direct drive machines are usually of the synchronous type (wound rotor or with magnets) with a large number of poles. However, for the generator power range of 0.5-15 kW (depending on the variation in the rated speed of the wind turbine), are not suitable for low speed applications [6,7,9,16,17].…”

“…There are also other architectures of direct-drive machines given in the literature such as those with variable reluctance excited with permanent magnets [16,17]. They belong to a class of stator-active machines with double saliency.…”

“…The recent advances in several fields (e.g., sensors technology, power electronics, materials etc.) help the DSPM machines to obtain performances comparable to those of PM synchronous machines [6,7,17,19]. However, the majority of this type of machines proposed for the wind power application are with the stator and rotor pole number, respectively, 6/4, 8/6, 12/10, 36/24 [20,21]; these machines are efficient when it comes to applications at high and medium speeds, but they become unsuitable at low speed ones, because their volume is directly linked to the value of its sizing torque.…”

Electromagnetic Torque Improvement of Doubly Salient Permanent Magnet Machine Using Pole Ratio Adjustment Technique

“…Next, the square envelope and asymmetrical-pole techniques were introduced for achieving larger slot area and lower torque ripple of DSPM (Zhang et al, 2019;Xu et al, 2020). Recently, several structural design techniques have been performed to improve the performance of DSPM, i.e., stator pole configuration design (Sriwannarat et al, 2018;Lounthavong et al, 2019;Lounthavong et al, 2020), partitioned-stator with asymmetrical pole (Sriwannarat et al, 2020a), optimizing the number of poles Sriwannarat et al (2019) and pole configuration adjustment technique (Sriwannarat et al, 2020b).…”