Rong‐Jie Wang

Chinese Academy of Civil Aviation Science and Technology

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Maarten J. Kamper

Stellenbosch University

Stiaan Gerber

Stellenbosch University

Nima Arish

Stellenbosch University

Morris Mugyema

Stellenbosch University

P. M. Tlali

Stellenbosch University

A. J. Sorgdrager

Magna (Austria)

C.D. Botha

Stellenbosch University

A. J. Grobler

North-West University

Vahid Teymoori

Stellenbosch University

Kamper Mj

Stellenbosch University

Cooperative Institutions

Stellenbosch University

East China University of Science and Technology

Huazhong University of Science and Technology

Chinese Academy of Sciences

State Key Laboratory of Chemical Engineering

Shihezi University

Tsinghua University

Xinjiang Production and Construction Corps

University of Cape Town

Shanghai Jiao Tong University

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Design optimization of a line-start PMSM considering transient and steady-state performance objectives

2022 IEEE Energy Conversion Congress and Exposition (ECCE) (2017)

A. J. Sorgdrager Rong‐Jie Wang A. J. Grobler

This paper investigates the use of the Taguchi method based regression rate optimization method for the design of line-start permanent magnet motors. A weighted factor multi-objective (MO) technique is used to take into account both steady-state and transient performance objectives. To validate the proposed method a prototype machine has been designed, constructed and experimentally evaluated. It shows that the proposed method can effectively take into account both steady-state and transient synchronization performance in the design of LS-PMSMs.

Transient (computer programming)

Line (geometry)

Transient state

10.1109/ecce.2017.8096853

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Citations (1)

Cogging Torque Definitions for Magnetic Gears and Magnetically Geared Electrical Machines

IEEE Transactions on Magnetics (2018)

Stiaan Gerber Rong‐Jie Wang

Although cogging torque in magnetic gears (MGs) has been studied, the additional degree of freedom inherent to MGs makes it unclear exactly what is defined as the cogging torque of a MG. Although MGs generally have relatively smooth torque transfer characteristics, this paper reveals that when the gear is used in an up-speed configuration, cogging effects may be amplified under startup conditions. This paper distinguishes between two kinds of cogging torque in MGs, termed the synchronous cogging torque and the true cogging torque. Calculation of the true cogging torque is more difficult than the synchronous cogging torque, but an approximation to the true cogging torque can be obtained using the synchronous cogging torque. The theory is verified experimentally and supported further by results from dynamic simulations. The impact on magnetically geared machines is also considered.

Cogging torque

Magnetic gear

Damping torque

10.1109/tmag.2017.2784823

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Citations (20)

Two-dimensional Cartesian air-gap element (CAGE) for dynamic finite-element modeling of electrical machines with a flat air gap

IEEE Transactions on Magnetics (2002)

Rong‐Jie Wang H. Mohellebi T.J. Flack Maarten J. Kamper J. D. Buys

This paper extends the air-gap element (AGE) to enable the modeling of flat air gaps. AGE is a macroelement originally proposed by Abdel-Razek et al. (IEEE Trans. Magn., vol. 17, pp. 3250-3252, 1981; ibid., vol. 18, pp. 655-659, 1982) for modeling annular air gaps in electrical machines. The paper presents the theory of the new macroelement and explains its implementation within a time-stepped finite-element (FE) code. It validates the solution produced by the new macroelement by comparing it with that obtained by using an FE mesh with a discretized air gap. It then applies the model to determine the open-circuit electromotive force of an axial-flux permanent-magnet machine and compares the results with measurements.

Air gap (plumbing)

10.1109/20.996024

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Citations (14)

Thermal analysis of a water-cooled interior permanent magnet traction machine

2022 IEEE International Conference on Industrial Technology (ICIT) (2013)

Rong‐Jie Wang G. C. Heyns

This paper presents the thermal analysis of a water-cooled interior permanent magnet (IPM) machine. An efficient quasi-3D lumped parameter thermal model is described and then applied to a practical IPM machine. The analytical model is validated by comparing its results with those obtained using detailed two-dimensional and three-dimensional finite element thermal analysis. Relevant conclusions are drawn.

10.1109/icit.2013.6505708

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Citations (18)

Load Angle of Flux Modulated Magnetic Gears

Progress In Electromagnetics Research C (2023)

Rong‐Jie Wang Stanley Robert Holm Josh Scheepers Stiaan Gerber

In this paper, the authors address the issue of flux-modulated magnetic gear (FMMG), which offers many potential advantages over traditional mechanical gears for a wide range of applications.In the proposed FMMG model, two permanent magnet (PM) carriers are of different pole-pairs and rotate asynchronously, and their relative angular position with respect to the pole parts of the flux modulator is not as straightforward and simple as it may seem in conventional electrical machines.Therefore, this paper focuses on the details of the derivation of FMMG load angle, which attempts to better express the angular relationship between the individual components of an FMMG.Finite element method (FEM) simulations and experiments are used to validate the load angle concept and corresponding results, and are complemented by experimental measurements.It is believed that the concept of loading angle can facilitate the design and simulation of FMMG and magnetically geared machines (MGM) based on the finite element method under different loading conditions.

10.2528/pierc23031603

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Citations (0)

Design and Optimization Techniques in Performance Improvement of Line-Start Permanent Magnet Synchronous Motors: A Review

IEEE Transactions on Magnetics (2021)

Mousalreza Faramarzi Palangar Wen L. Soong Nicola Bianchi Rong‐Jie Wang

This article covers the design methodologies and optimization techniques studied in the performance improvement of line-start permanent magnet synchronous motors (LSPMSMs). LSPMSM performance improvement using design techniques are chiefly limited to either the transient or the steady-state performance improvement, and a focus on only the transient performance improvement may degrade the steady-state performance of the LSPMSM and vice versa. Optimization studies of LSPMSMs can be categorized in terms of optimization aim in three classifications: transient performance improvement, steady-state performance improvement, and simultaneous improvement of both transient and steady-state performances. This study indicates the impact of various variables on the LSPMSM performance improvement. The optimization review shows that starting cage optimization without considering the steady-state characteristics as constraints results in synchronous performance degradation. The steady-state performance optimization with transient characteristics as constraints results in a minor synchronous performance improvement though there is the lowest transient performance sacrifice. Multi-objective optimization, including a transient and a steady-state characteristic as individual objectives, resulted in a more optimum LSPMSM with overall performance improvement. Finally, suggestions for optimization implementation of LSPMSMs are presented for future research work.

Transient (computer programming)

Performance Improvement

Performance Prediction

Synchronous motor

10.1109/tmag.2021.3098392

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Citations (23)

Accurate prediction of three-phase short-circuit currents of PM synchronous machines

IET conference proceedings. (2023)

F. Eichin Maarten J. Kamper Stiaan Gerber Rong‐Jie Wang

Since the advent of rare-earth permanent magnet (PM) materials, the PM synchronous machine (PMSM) has gained popularity in various applications, including power generation systems, industrial drives, and e-Mobility. However, the rare-earth PMs commonly used in PMSMs are inherently prone to both temperature and operation related irreversible demagnetisation risks. To realise a fault-tolerant machine design, it is essential to consider these fault conditions during the design phase of a PMSM. Traditionally, this involves time-consuming transient finite element analysis (FEA). To make it computationally more viable, fast analytical-based simulation approaches are very attractive alternatives. This paper assesses various methods for analysing dynamic three-phase short-circuit (3PSC) currents in PMSMs, with an aim to improve overall accuracy. Experimental measurements are conducted on a PMSM prototype and used as a benchmark for this study. It shows that the discrepancy between the measured and predicted results is less when machine saturation is considered. While spatial harmonic content and subtransient reactance may be neglected in the 3PSC fault simulation for specific machine types, it is crucial to exercise discretion when applying them in other scenarios.

Reactance

Synchronous motor

Transient (computer programming)

Benchmark (surveying)

Harmonic Analysis

Harmonic

10.1049/icp.2023.2028

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Citations (1)

Statistical analysis of cogging torque considering various manufacturing imperfections

Stiaan Gerber Rong‐Jie Wang

Cogging torque in permanent magnet machines is undesirable because it is a source of noise and vibration and because it has a negative impact on controllability. Over the years, many design techniques that can effectively reduce cogging torque have been developed. However, due to manufacturing tolerances, a machine's cogging torque characteristics often deviate from that intended with the design. In this paper, an analytical model of cogging torque in permanent magnet machines with surface-mounted magnets is developed. The model is capable of accounting for various manufacturing imperfections that can have an impact on cogging torque. The low computational complexity of the model allows statistical analyses of the cogging torque to be conducted using Monte Carlo simulations. Using this approach, it is possible to obtain the probability density distribution of the cogging torque, given the error distributions of critical machine features.

Cogging torque

10.1109/icelmach.2016.7732807

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Citations (10)

Performance Comparison of Induction Motor and Line Start PM Motor for Cooling Fan Applications

C Mutize Rong‐Jie Wang

This paper presents the design of a line-start permanent magnet (LSPM) motor by modifying a commercial premium efficiency cage induction motor (IM) for cooling fan applications. Two-dimensional transient finite element (FE) analysis is applied to both IM and LSPM motor to compare their starting and synchronization performance for fan-type load. It clearly shows that the LSPM motor has better efficiency and power factor than that of IM at steady-state. However, the transient starting performance of the LSPM compares less favorably with that of the IM.

Transient (computer programming)

Line (geometry)

Source

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Citations (2)

Design and Comparison of Three Surface-Mounted PM Motors for a Light Electric Vehicle

2019 Southern African Universities Power Engineering Conference/Robotics and Mechatronics/Pattern Recognition Association of South Africa (SAUPEC/RobMech/PRASA) (2021)

Francois du Plessis Stavros Pastellides Rong‐Jie Wang

Electric vehicles (EV) are increasingly used in both urban and industrial environments. Electric motors are the essential part of the EV power train systems. Different types of electric motor technologies have been developed for the purpose. Amongst others, permanent magnet synchronous motors (PMSM) are widely used for EV applications because of their unique advantages such as high efficiency and high power density. This paper presents the optimal design of three different surface-mounted PMSMs with fractional-slot tooth-concentrated and distributed winding topologies, respectively. The performance comparison of these motors will outline their respective advantages and disadvantages.

Synchronous motor

Power density

10.1109/saupec/robmech/prasa52254.2021.9377239

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Citations (2)