Operating Performance Of Motor Research Articles

Current Harmonic Suppression of BLDC Motor Utilizing Frequency Adaptive Repetitive Controller

Compared to the proportional-integral strategy, the repetitive control strategy possesses high suppression ability for the alternating current (AC) harmonics of control signals. Thus, RC controllers are widely used in closed-loop control systems to suppress the periodic harmonics. In order to further improve the brushless DC (BLDC) motor operation performance, a frequency adaptive repetitive controller (FARC) is proposed, and then a novel current loop scheme that concatenation of proportional-integral controller (PIC) and FARC controller is established in this paper. Firstly, due to the real sampling number of the delay element in the BLDC, the motor control system may not be an integer, the designing process of the FARC parameters was studied, and an adaptive internal model controller and a novel decomposition rule for FARC were designed based on Lagrange interpolation theory. Secondly, the PIC parameters were analyzed through three-dimensional and two-dimensional images of the frequency characteristics. Furthermore, a composite controller that added a forward channel in the novel current loop was proposed, and the stability of the control system used the composite controller was analyzed through Lyapunov theory. It should be noted that the analysis of FARC mainly focused on the simplified structure and the parameter optimization, which is usually ignored in the previous studies. Finally, the BLDC motor control system model was established through Matlab/Simulink software, and the operation performances of the BLDC motor control system utilizing different current loop controllers were studied. The simulation results show that the proposed FARC can reduce current distortion and torque ripples, thus, the BLDC motor operation performances can be improved effectively.

A direct field‐circuit coupled analytical modelling method for permanent magnet motor operation performance analysis

In this paper, the analytical relationship among supply voltage, current, and structure parameters of the permanent magnet (PM) motor is cleverly deduced by using an intermediate-flux linkage. After further consideration of boundary conditions, the direct field-circuit coupled analytical model in integrated matrix form is subsequently constructed. Using this model, the vector potentials and currents of the motor can be calculated simultaneously, and the electromagnetic performance, such as the output torque, winding flux linkage, and so on can be further calculated by the vector potentials. Because the control parameters and motor structure parameters are both considered in the derivation process, the proposed analytical model can be used to analyse the motor operation performance under different control strategies. Its validity is finally verified on a 10-pole/12-slot PM motor. The results of the proposed direct field-circuit coupled analytical model are compared with those of field-circuit coupled time-stepping finite element model and experiment under speed-current double closed-loop and current closed-loop control strategies, respectively. The results of the proposed model are proved well with finite element simulation and experimental results.

Investigation of the Torque Production Mechanism of Dual-Stator Axial-Field Flux-Switching Permanent Magnet Motors

This paper studies the torque production mechanism of the dual-stator axial-field flux-switching permanent magnet (DSAFFSPM) machine. Due to the double-sided slotting design of such topology, more resultant air-gap working harmonics in the air-gap flux density are responsible for the torque production and the stator air-gap permeance is especially considered in the investigation. Based on the magnetic force (MMF)-permeance model, the composition and difference of the air-gap working harmonics are demonstrated. The DSAFFSPM machine torque contributions of the main working harmonics are analyzed theoretically and quantified by finite element analysis (FEA). The influence laws of the parameters on the working harmonics are shown and this effectively improves the motor operation performance. Finally, some experiments on the DSAFFSPM machine are carried out to validate the analytical and FEA results.

Robust Control for Active Suspension of Hub-Driven Electric Vehicles Subject to in-Wheel Motor Magnetic Force Oscillation

In this paper, after investigating the coupling effect in a permanent magnet synchronous in-wheel motor, a robust control method for active suspension of hub-driven electric vehicles (EVs) to enhance the performance of the in-wheel motor and the vehicle is proposed. Based on the electric vehicle model addressing the coupling effect between the electromagnetic excitation of the permanent magnet synchronous motor (PMSM) and the transient dynamics in EVs, the influence of the coupling effect on the motor and the vehicle performance is analyzed. The results reflect that the coupling effect in in-wheel motors intensifies the magnetic force oscillation, aggravates the eccentricity of the rotor, deteriorates the motor operation performance, and worsens the ride comfort. To suppress the magnetic force oscillation in motor and enhance the vehicle comfort, the active suspension system considering five aspects of suspension performance is introduced. Simultaneously, on the basis of Lyapunov stability theory, a reliable robust Hꝏ controller considering model uncertainties, actuator failure and electromagnetic force interference is designed. The simulation results reflect that the robust Hꝏ feedback controller can not only achieve better ride comfort, but also restrain the coupling effect in the motor. Meanwhile the other requirements such as the road holding capability, the actuator limitation, and the suspension deflection are also maintained. The proposed robust control method demonstrates a potential application in the practice of EV control.

Coupling effect between road excitation and an in-wheel switched reluctance motor on vehicle ride comfort and active suspension control

The coupling effect between road excitation and an in-wheel switched reluctance motor (SRM) on vehicle ride comfort is numerically analysed. A hybrid control system consisting of fault tolerant H∞ suspension controller and SRM controller for an in-wheel SRM driven electric vehicle is proposed to improve the vehicle ride comfort and motor operation performance. By conducting numerical simulations based on the developed quarter-car active suspension model and switched reluctance motor model, it is observed that the road roughness is highly coupled with SRM airgap eccentricity and unbalanced residual vertical force. The SRM airgap eccentricity is influenced by the road excitation and becomes time-varying such that a residual unbalanced radial force is induced; which is one of the major causes of SRM vibration. To suppress SRM vibration and to prolong the SRM lifespan, while at the same time improving vehicle ride comfort, a fault tolerant controller based on output feedback H∞ control method is designed to reduce the sprung mass acceleration. Moreover, an SRM controller is adapted by using the combined Current Chopping Control (CCC) and Pulse Width Modulation control (PWM) to further improve the SRM performance. A comparison of passive suspension and suspensions with hybrid control method on the vehicle and SRM dynamic response under stochastic road excitation and bump road excitation is illustrated. The results indicate that the proposed hybrid control method can effectively reduce the SRM airgap eccentricity, residual unbalanced radial force and achieve better vehicle ride comfort.

Investigation and Countermeasures for Demagnetization in Line Start Permanent Magnet Synchronous Motors

Line start permanent magnet synchronous motors (LSPMSM) may get demagnetized under some special conditions. The demagnetization is usually investigated with finite element analysis (FEA) by using the nominal properties of the magnets. However, the properties decay after the magnets have suffered the demagnetizing magnetic motive force (DMMF), causing spread of the demagnetization area. Therefore, it is proposed in this paper that iteration of FEA should be taken, considering the decaying of the magnets properties. Moreover, four rotor configurations are proposed, so as to enhance the anti-demagnetization capability. FEA with these four configurations proves that the comprehensive configuration with both dual squirrel cages and magnetic barriers on the rotor is rather effective to protect the magnets, but hardly deteriorates the motor operation performance under the rated condition.

Torque ripple minimisation control method for a four‐phase brushless DC motor with non‐ideal back‐electromotive force

In conventional control methods of brushless DC (BLDC) motor drives, back-electromotive force (EMF) is assumed to be in ideal form and the controller injects rectangular phase current commands to produce the desired constant torque. However, real back-EMF waveform might not be exactly trapezoidal because of non-ideality of magnetic material, design considerations and manufacturing limitations. This makes the generated electromagnetic torque contain ripples in its waveform which is not desirable in motor operation performance especially, in sensitive industries. Moreover, commutation states affect the quality of generated torque by producing torque pulsations because of changes of conducting phases. In this study a control strategy for a four-phase BLDC motor with non-ideal back-EMF to reduce electromagnetic torque ripples is presented. Basis of the proposed method is to inject phase currents considering back-EMF instantaneous magnitude. For this purpose, an on-line back-EMF estimation technique is used to inject appropriate phase currents to compensate non-ideality of back-EMF waveform. Moreover, the estimated back-EMF is also used for commutation torque ripple reduction. The experimental results indicate performance of the proposed control strategy in torque pulsations reduction compared with conventional control method.

Radial Laminated Magnetic-Barrier Rotor Optimization Design of Brushless Doubly-Fed Machine

This paper establishes four kinds of Brushless Doubly-Fed Machine (BDFM) models with radial laminated magnetic-barrier rotor using ANSOFT finite element software, calculates the electromagnetic field of these four kinds of models, comparatively analyzes the magnetic field distribution, the torque capability, the end winding characteristics ,the rotor’s radial magnetic forces, the core losses and the motor operating performance of motor with different rotor structures, and thus provides theoretical guidance for optimization design of radial laminated magnetic-barrier rotor structure.