An Improved Sideband Current Harmonic Model of Interior PMSM Drive by Considering Magnetic Saturation and Cross-Coupling Effects

The sideband current harmonics, as parasitic characteristics in permanent-magnet synchronous machine (PMSM) drives with space vector pulsewidth modulation technique, will increase the corresponding electromagnetic loss, torque ripple, vibration, and acoustic noises. Therefore, fast yet accurate evaluation of the resultant sideband current harmonic components is of particular importance during the design stage of the drive system. However, the inevitable magnetic saturation and cross-coupling effects in interior PMSM drives would have a significant impact on the current components, while the existing analytical sideband current harmonic model neglects those effects. This paper introduces a significant improvement on the analytical model by taking into account these effects with corresponding nonlinear factors. Experimental results are carried out to underpin the accuracy improvements of the predictions from the proposed model over the existing analytical one. The proposed model can offer a very detailed and insightful revelation of impacts of the magnetic saturation and cross-coupling effects on the corresponding sideband current harmonics

Analytical investigation of sideband electromagnetic vibration in integral-slot PMSM drive with SVPWM technique

This paper provides a comprehensive investigation into the electromagnetic vibration associated with the sideband harmonic components introduced by space vector pulse width modulation applied in integral-slot permanent magnet synchronous machine drives. The critical permanent magnet, armature reaction, and sideband magnetic field components, which are the primary causes for sideband electromagnetic vibration in integral-slot permanent magnet synchronous machines, are identified. The analytical derivations of the magnetic field components are carried out, and amplitudes and frequencies of the resultant sideband radial electromagnetic force components are obtained. Furthermore, the proposed models of the sideband radial electromagnetic force components are incorporated into the vibration model to analytically evaluate the corresponding sideband electromagnetic vibrations of the machine. Experimental tests on an integral-slot permanent magnet synchronous machine drive are comprehensively performed to confirm the validity and accuracy of the analytical models. Not only can the validated analytical models offer insightful details in understanding the impacts of the key factors, such as operation conditions, machine geometry, electromagnetic and power converter parameters, on the sideband electromagnetic vibration, but also can be readily extended to assess and reduce noise in integral-slot permanent magnet synchronous machine drives

Multi-objective optimal design of a toroidally wound radial-flux halbach permanent magnet array limited angle torque motor

This paper presents the modeling, optimization and validation of a toroidally wound radial-flux Halbach array permanent magnet limited angle torque motor. A fully parameterized and flexible equivalent magnetic circuit model of the proposed motor, which is arranged in matrix form by means of Kirchhoff’s current laws for computational efficiency and ease of extension, is introduced for preliminary design. To optimize the design, a multi-objective optimization process is carried out and the multi-objective particle swarm optimization method is used to obtain the Pareto front of the desired objectives. An approved solution in Pareto front is selected and validated by finite element analysis method. A prototype based on the final design is built and tested. The experiment results further underpin the effectiveness of the proposed design and optimization approach

Control strategy for a modified cascade multilevel inverter with dual DC source for enhanced drivetrain operation

This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase series-connected respectively to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimise energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimise switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications

Control strategy for a modified cascade multilevel inverter with dual DC source for enhanced drivetrain operation

This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase seriesconnected respectively to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimise energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimise switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications

Preliminary design and optimization of toroidally-wound limited angle servo motor based on a generalized magnetic circuit model

This paper proposes a new generalized equivalent magnetic circuit model for the preliminary design of a toroidally-wound limited angle servo motor (LASM). In the model, the magnetic networks are formulated as a function of the pole number and geometric dimensions. Nonlinear saturation effect of the ferromagnetic material is also taken into consideration. A multi-objective optimization function involving the torque requirement, the mass, the time constant, and magnetic saturations of ferromagnetic material is introduced. Based on the proposed model, six design cases with different objectives have been carried by the particle swarm optimization (PSO) method. The comparisons of different optimization cases demonstrate the effectiveness and computation efficiency of the proposed method, and hence its suitability in preliminary design. Moreover, the generalized model can be readily applied in the other electromagnetic modelling

Toward an intelligent high frequency AC distributed power system - Part II: Analytical modelling and experimental realization

High frequency AC (HFAC) distributed power systems (DPS), where electric power is delivered at up to multi-kHz via cables, is an alternative means to conventional centralized power systems. This paper explores the means by which real-time information can be achieved without installing additional physical communication channels on an existing 50 kHz current-fed HFAC DPS in lighting applications. A communication protocol is methodologically developed to facilitate robust and efficient inter-device real-time communication. In addition, analytical modelling for the current fed coupling circuit is presented. The utility of an intelligent HFAC DPS is demonstrated by experimental results from comprehensive circuit level implementation. Copyright © 2016 Praise Worthy Prize - All rights reserved

Preliminary design and multi-objective optimization of electro-hydrostatic actuator

Electro-hydrostatic actuator is generally regarded as the preferred solution for more electrical aircraft actuation systems. It is of importance to optimize the weight, efficiency and other key design parameters, during the preliminary design phase. This paper describes a multi-objective optimization preliminary design method of the electro-hydrostatic actuator with the objectives of optimizing the weight and efficiency. Models are developed to predict the weight and efficiency of the electro-hydrostatic actuator from the requirements of the control surface. The models of weight prediction are achieved by using scaling laws with collected data, and the efficiency is calculated by the static energy loss model. The multi-objective optimization approach is used to find the Pareto-front of objectives and relevant design parameters. The proposed approach is able to explore the influence of the level length of linkage, displacement of pump and torque constant of motor on the weight and efficiency of the electro-hydrostatic actuator, find the Pareto-front designs in the defined parameter space and satisfy all relevant constraints. Using an electro-hydrostatic actuator for control surface as a test case, the proposed methodology is demonstrated by comparing three different conditions. It is also envisaged that the proposed prediction models and multi-objective optimization preliminary design method can be applied to other components and systems

Particle swarm optimization of air-cored axial flux permanent magnet generator for small-scale wind power systems

Axial flux permanent magnet synchronous machines with aircored configuration is particular suitable for small scale wind power system due to their advantages of low synchronous reactance, cogging torque free, high efficiency and high power factor. However, due to the number of machine parameters, with some tightly `coupled' with each other, optimisation of the design could become extremely challenging by conventional analytical means. Here, the particle swarm optimization method is used in the design of an axial flux permanent magnet generator for small-scale wind power system. Five inter-dependent design parameters are adjusted simultaneously to achieve an optimal solution for the application. Three-dimensional finite element analysis is employed to evaluate the electromagnetic performance for the optimization. The results show the proposed optimization method is efficient and with fast convergence