Instantaneous current profile control for flat torque of switched reluctance motors

Abstract

SUMMARYThis paper presents a new instantaneous current control to obtain an instantaneously flat torque waveform with smaller torque ripples of switched reluctance motors (SRMs). The proposed current control is based on table lookup. By geometric insights for the machine and finite element method based analysis, ideal current profiles for the flat torque are generated. Some simulation results are presented to demonstrate the validity of the proposed control, which are verified by experiment.

New Drive Circuit for Reducing the Switching Current Ripples in Switched Reluctance Motors

“…With methods of the second group, SRM structure remains unchanged; instead, stator current waveforms are controlled so that instantaneous torque is kept constant [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. By realizing such stator current waveforms, one can compensate for nonlinearity of current and torque characteristics with respect to rotor position and rotation speed.…”

“…There are also methods to calculate reference current waveforms using rotor position, current, and torque characteristics acquired through electromagnetic field analysis, and so on. [13][14][15][16]. In so doing, reference current waveforms are generated based on trapezoidal-wave current [13][14][15], or calculated with regard to trackability of actual current via rotor position, current, and torque characteristics [16].…”

Controlled Voltage Source Vector Control for Switched Reluctance Motors Using PWM Method

“…The former features by simple controller design and good responsiveness as well as high stability against variation of motor parameters. Thus, current control by CCS using HC scheme is normally used for SRMs with strongly nonlinear magnetization characteristics while clear mathematical models are not available [7,13]. However, in such scheme, switching frequency varies randomly with inverter's dc link voltage, operating load, and other factors, which may excite motor's natural vibrations and generate large noise [8,9].…”

Research of Electro-mechanical Actuator in Electric Braking System Based on Instantaneous Torque Control with SRM

“…As 8/6 SRM is concerned, two-phase excitation control strategy can effectively reduce starting torque ripple, but as speed increases, the mutual flux has greater impact on the torque, and the two-phase excitation strategy is difficult to reduce torque ripple during commutation [11]. In addition, some scholars have proposed the use of an ideal current distribution to get a smooth torque in order to achieve the purpose of suppressing the torque ripple, but due to the higher speed, the rate of change of current becomes greater, so it makes difficult to track the actual current for given current [12]. As the electromagnetic properties of SRM is highly nonlinear and strong coupling, even injecting constant current to the phase winding, the instantaneous torque generated will not be smooth.…”