Browsing by Author "Liang, Wenyi"
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Item Open Access Analytical investigation of sideband electromagnetic vibration in integral-slot PMSM drive with SVPWM technique(Institute of Electrical and Electronics Engineers (IEEE), 2016-09-13) Liang, Wenyi; Fei, Wei-Zhong; Luk, Patrick Chi-KwongThis 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.Item Open Access Analytical modeling of current harmonic components in PMSM drive with voltage-source inverter by SVPWM technique(IEEE, 2014-04-22) Liang, Wenyi; Wang, Jianfeng; Luk, Patrick Chi-Kwong; Fang, Weizhong; Fei, Wei-ZhongThe sideband current harmonic components would inhere in permanent-magnet (PM) synchronous machine systems driven by a voltage-source inverter with space vector pulsewidth modulation (SVPWM). However, these harmonics could potentially deteriorate the overall performance of the drive system by increasing the resultant losses, torque ripple, and electromagnetic and acoustic noises. The main sideband harmonic voltages and currents in PM synchronous machine driven by voltage-source inverter with SVPWM technique, are analytically derived and expressed in both stator and rotor frame. The experimental results are carried out to underpin the validity of the analytical model. The analytical model could be employed to assess the influencing factors of current harmonics. In addition, it offers insightful guidance to the effective reductions of harmonic losses, torque ripples, and electromagnetic noises.Item Open Access The analytical study of stator tooth modulation on electromagnetic radial force in permanent magnet synchronous machines(IEEE, 2020-12-02) Liang, Wenyi; Wang, Jianfeng; Luk, Patrick Chi-Kwong; Fei, Wei-ZhongThe electromagnetic radial force acting on the stator inner periphery will induce radial vibration and acoustic noise in permanent magnet machines. The radial force components are transmitted through the stator teeth to the yoke to introduce deformations. The influence of the stator tooth structure can be considered as an equivalent mechanical modulation effect on these electromagnetic radial force components. As a result, high-order electromagnetic radial force components can be modulated and potentially result in eminent stator low-mode vibration. In this paper, an analytical model is developed to offer an intuitive knowledge of stator tooth modulation effect on electromagnetic radial force. The validity of the proposed analytical method has been underpinned by both finite element analysis and experimental results. Such an effective yet simple analytical model can be of significant benefit for the stator radial vibration analysis. It can be employed to not only promptly investigate the stator radial vibration characteristics but also perform effective optimization on stator radial vibration reduction in permanent magnet machinesItem Open Access An improved sideband current harmonic model of interior PMSM drive by considering magnetic saturation and cross-coupling effects(Institute of Electrical and Electronics Engineers, 2016-03-10) Liang, Wenyi; Fei, Wei-Zhong; Luk, Patrick Chi-KwongThe 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.Item Open Access The investigation of electromagnetic radial force and associated vibration in permanent magnet synchronous machines(Cranfield University, 2017-02) Liang, Wenyi; Luk, Patrick Chi-KwongThe rising public awareness of climate change and urban air pollution has been one of the key drivers for transport electrification. Such trend drastically accelerates the quest for high-power-and-torque-density electric drive systems. The rare-earth permanent magnet synchronous machine, with its excellent steady-state and dynamic characteristics, has been the ideal candidate for these applications. Specifically, the fractional-slot and concentrated-winding configuration is widely adopted due to its distinctive merits such as short end winding, low torque pulsation, and high efficiency. The vibration and the associated acoustic noise become one of the main parasitic issues of high-performance permanent magnet synchronous drives. These undesirable features mainly arise from mechanical connection failure, imperfect assembly, torque pulsation, and electromagnetic radial and axial force density waves. The high-power-and-torque-density requirement will only be ultimately fulfilled by the reduction of both electromagnetic active material and passive support structure. This results in inflated electromagnetic force density inside the electric machine. Besides, the sti.ness of the machine parts can be compromised and the resultant natural frequencies are significantly brought down. Therefore, the vibration and acoustic noise that are associated with the electromagnetic radial and axial force density waves become a burden for large deployment of these drives. This study is mainly dedicated to the investigation of the electromagnetic radial forced density and its associated vibration and acoustic noise in radial-flux permanent magnet synchronous machines. These machines are usually powered by voltage source inverter with pulse width modulation techniques and various control strategies. Consequently, the vibration problem not only lies on the permanent magnet synchronous machine but also highly relates to its drive and controller. Generally, the electromagnetic radial force density and its relevant vibration can be divided into low-frequency and high-frequency components based on their origins. The low-frequency electromagnetic radial force density waves stem from the magnetic field components by the permanent magnets and armature reaction of fundamental and phase-belt current harmonic components, while the high-frequency ones are introduced by the interactions between the main low-frequency and sideband highfrequency magnetic field components. Both permanent magnets and armature reaction current are the main sources of magnetic field in electric machines. Various drive-level modeling techniques are first reviewed, explored, and developed to evaluate the current harmonic components of the permanent magnet synchronous machine drive. Meanwhile, a simple yet e.ective analytical model is derived to promptly estimate the sideband current harmonic components in the drive with both sinusoidal and space-vector pulse width modulation techniques. An improved analytical method is also proposed to predict the magnetic field from permanent magnets in interior permanent magnet synchronous machines. Moreover, a universal permeance model is analytically developed to obtain the corresponding armature-reaction magnetic field components. With the permanent magnet and armature-reaction magnetic field components, the main electromagnetic radial force density components can be identified and estimated based on Maxwell stress tensor theory. The stator tooth structure has large impacts on both electromagnetic radial force density components and mechanical vibration behaviors. The stator tooth modulation e.ect has been comprehensively demonstrated and explained by both finite element analysis and experimental results. Analytical models of such e.ect are developed for prompt evaluation and insightful revelation. Based on the proposed models, multi-physics approaches are proposed to accurately predict low-frequency and high-frequency electromagnetic radial vibration. Such method is quite versatile and applicable for both integral-slot and fractional-slot concentrated-winding permanent magnet synchronous machines. Comprehensive experimental results are provided to underpin the validity of the proposed models and methods. This study commences on the derivations of the drive parameters such as torque angle, modulation index, and current harmonic components from circuit perspective and further progresses to evaluate and decouple the air-gap magnetic field components from field perspective. It carries on to dwell on the analytical estimations of the main critical electromagnetic radial force density components and stator tooth modulation e.ect. Based on the stator mechanical structure, the corresponding electromagnetic radial vibration and acoustic noise can be accurately predicted. Various analytical models have been developed throughout this study to provide a systematic tool for quick and e.ective investigation of electromagnetic radial force density, the associated vibration and acoustic noise in permanent magnet synchronous machine drive. They have all been rigorously validated by finite element analysis and experimental results. Besides, this study reveals not only a universal approach for electromagnetic radial vibration analysis but also insightful correlations from both machine and drive perspectives.