Design of a mutually coupled external‐rotor direct drive E‐bike switched reluctance motor

Abstract

In this paper, a concentrated-wound exterior-rotor direct-drive electric bicycle (e-bike) mutually coupled switched reluctance motor (MCSRM) has been designed to match the performance parameters and dimensional constraints of a commercially available permanent magnet e-bike motor. Different stator and rotor pole configurations are compared for a 3phase MCSRM. During the design process, many parameters have been evaluated and analysed. The finalised performance capabilities of all pole configurations are summarised, and the choice of pole configuration for the final design is justified. The full dynamic torque-speed performance of the finalised 15/10 MCSRM is presented, along with a detailed thermal analysis. Finally, the MCSRM performance is compared to a 12/16 non-coupled SRM and a commercially available permanent magnet motor.

Model-Based Spatial Harmonics Vector Compensation Method for Three-Phase Mutually Coupled Switched Reluctance Machine With Sinusoidal Current Excitation

“…The reference currents in Fig. 6 are 10,5] A and the THD is improved from 23% to 4%. The THD in Fig.…”

“…The 3-phase voltages when [i d , i q ] = [10, 5] A at 1500 rpm are obtained from the FEA model, they are referred to as v u,v,w_FEA , and they are the essential 3-phase voltages to create the sinusoidal currents when they are applied to the MCSRM. The 3-phase reference voltages from the dynamic model when 10,5] A at 1500 rpm using the standard vector control with and without the proposed method are obtained as well, and they are referred to as v * u,v,w and v u,v,w_PI , respectively. Afterwards, the 3-phase voltages from the FEA model and the dynamic model are transformed into the dq synchronous reference frame.…”

“…The harmonics of phase current do not exist in (9) as the FEA model is based on sinusoidal current excitation. By considering the coefficients of the same trigonometric function in (9), the Fourier coefficients of the harmonic voltage vectors are calculated as: Equation (10) shows that the Fourier coefficients of the harmonic voltage vectors (V an and V bn ) are the multiplication of the flux linkage Fourier coefficients (ψ an and ψ bn ), the electrical angular frequency (w), and the harmonic order (n). As a result, the dominant spatial harmonics of the phase voltage have higher orders than the flux linkage.…”

“…Several current waveforms can be used for MCSRMs including sinusoidal waveform [9], [10], unipolar rectangular waveform [11], [12], and bipolar rectangular waveform [7], [13], [14]. For MCSRMs with sinusoidal current excitation, authors in [9] show that the double layer short-pitched MC-SRM has the highest efficiency compared to other configurations.…”

Dynamic Vector Modeling of Three-Phase Mutually Coupled Switched Reluctance Machines with Single dq-Quadrant Look-up Tables

“…The winding configuration is changed to make the motor operates as a MCSRM with sinusoidal current excitation. SRMs which are designed to operate as MCSRM can have much lower torque ripple [30]- [32].…”