A Comparative Study of Dual Stator With Novel Dual Rotor Permanent Magnet Flux Switching Generator for Counter Rotating Wind Turbine Applications

Abstract

Compared with the single rotor wind turbine, a counter-rotating (CR) wind turbine with two rotor sets leads to twice power density. In this regard, dual stator CR (DSCR) permanent magnet flux switching generator (DSCR-PMFSG) is employed. However, in DSCR-PMFSG both rotor and armature parts are rotating and require slip rings for power transmission. The slip rings associate demerits of constant maintenance, poor speed regulation, increased cost, and additional slip ring losses, whereas DSCR-PMFSG offer lower flux and lesser power density. To overcome the demerits as mentioned earlier of DSCR-PMFSG, this paper proposed a novel dual rotor counter-rotating permanent magnet flux switching generator (DRCR-PMFSG) for wind turbine applications that eliminate the requirements of slip rings and retain brushless operation. The proposed DRCR-PMFSG share one stator connected back-to-back through a flux bridge that provides an alternate flux path between two mechanical ports associated with the inner rotor and outer rotor, contributing to the cumulative output. A detailed comparative analysis of DSCR-PMFSG and DRCR-PMFSG is performed under static characteristics, overload, and wide speed range to generate output power, voltage, current, power density, and efficiency. Quantitative comparative analysis under static analysis evident that proposed DRCR-PMFSG exhibits 33.29% higher flux, suppressed cogging torque and torque ripples up to 53.48% and 67.45%, respectively. Furthermore, a comprehensive quantitative analysis is performed under coupled overload and over-speed capability. The analysis exposes that in comparison with DSCRP-PMFSG, the proposed DRCR-PMFSG improves voltage regulation factor by 55.88%, output current enhanced by 67.9%, raise output voltage to 2.01 times, and power density to 1.72 times while maintaining the efficiency of 90.195% and achieving stable voltage profile with load variation. Finally, a detailed comparative analysis with conventional designs is performed and comprehensive mathematical modelling based on sub-domain model is developed accounting stator slot and rotor pole combinations, magnetic saturation, and winding configuration to validates finite element analysis (FEA) utilizing JMAG Designer v.20.1.

Review of Control Topologies for Flux Switching Motor

“…• Good disturbance rejection capability with reduced torque ripple With these objectives under consideration, different configurations of FSM are under research to support applications like hybrid electric vehicles [5], [6], [7], [8], [9], [10], [11], [70] locomotive traction [12], [13], [14], downhole [15], wind energy conversion systems [16], [17], [18], [19], [71], aerospace [20], [21], elevator [22] and household appliances [23], [24], [25], [26]. Although there had been many advancements in the design of FSM, researchers started to explore controller algorithms for FSM only after the year 2008 [30].…”

Dual mechanical port power distribution in dual rotor permanent magnet flux switching generator for counter‐rotating wind turbine applications

“…It is noteworthy that a higher pulsating torque results vibration and acoustic noise which is undesirable and can be suppressed through rotor pole shaping [35]. A detailed study of the rotor pole shaping for cogging torque and torque ripples suppression in the proposed DMPDRCR-PMFSG is investigated in [36], which effectively shows suppression of undesirable cogging torque and torque ripple ratio.…”

An analytical formula for back EMF waveform of a counter‐rotating dual‐rotor non‐slotted axial flux permanent magnet synchronous machine

“…The use of this type of counter-rotating machine results in improving the performance of wind turbine systems compared to the conventional generator, even for producing low electrical power [26,27]. Since the proposed structure has two rotors, it exhibits twice the power density compared to the single-rotor structure [28,29]. In addition, the use of PM in the proposed structure leads to an increase in the reliability of counter-rotating wind turbine systems [3,31].…”