Iet Electric Power Applications最新文献

Vibration signal analysis plays a vital role in the condition-based preventive maintenance of induction motor by identifying early signs of motor issues, avoiding costly breakdowns and optimising the motor's maintenance schedule. It provides detailed information very useful for extending the motor's life cycle with proactive, condition-specific maintenance. Furthermore, the vibration signal analysis offers the advantage of identifying the health status of rotating machinery as a whole, as well as its individual components. This paper presents an innovative solution for the automated health assessment of a critical induction motor component: the bearing. Our approach uses the matrix pencil method for signal processing and health signature generation, combined with a multilayer perceptron neural network to detect health conditions from the resulting health signature characteristics. Initially, the matrix pencil is applied to the vibration signal to identify the mean frequency characteristics. This vector provides a holistic view of the signal’s inherent features and transforms its frequency characteristics into a visual spectrum, resulting in improved induction motor bearing fault condition monitoring. Subsequently, the output from the matrix pencil mean frequency analysis is processed by a multilayer perceptron neural classifier, chosen for its low computational cost and high classification accuracy. Experimental validation demonstrates a 100% fault classification rate and automatic identification of defective components. Comprehensive validation further confirms the method’s robustness and feasibility for induction motor bearing fault detection compared to other recently methods.

This paper presents a modified structure of synchronous reluctance motors (SynRMs) combined with a new design strategy in which hybrid optimisation is considered to enhance line start capability and power factor. The rotor design, along with some embedded permanent magnets (PMs), has an important effect on the static performance. In the proposed SynRM, the rotor bars are designed for the flux barriers, and some additional bars are considered near the q-axis. The PM arrangement is changed so that some additional PMs are considered. In the proposed design strategy, two optimisation procedures called local and global optimisation phases are considered. In the first step, genetic algorithm (GA) is used to obtain optimal geometric parameters for some performance metrics. In the next step, the global response surface method is applied to combine the mentioned metrics and determine the globally optimal design for both stator configurations. In the last optimisation process, improvement of line-start capability and power factor are proposed as the main goals. The analysis results show that the design proposed by SynRM has better performance in terms of line-start capability and power factor. Experimental validation of the proposed SynRM is also presented to confirm the accuracy of the finite element method (FEM) simulation.

Hashem Yousefi Javid and Aydin Yousefi Javid (2025). Modelling and Simulation of a Novel Axial Flux Permanent Magnet Hysteresis Motor Comparing Different Disc Structures. IET Electric Power Applications. 19. https://doi.org/10.1049/elp2.70008.

In Section 3.3 of the original publication, the reference to Equations 1 and 2 was incorrect. This has been updated to correctly refer to Equations 8 and 9. Furthermore, Equations 8 and 9 have now been accurately presented to the following:

We apologise for this error.

Large variable-speed pumped storage generator-motors (VSPSGMs) offer superior speed adaptability and rapid adjustment capabilities for both active and reactive power. However, their rotor AC excitation systems pose significant challenges for electromagnetic design and ventilation cooling due to variable operational conditions. In this paper, the electromagnetic parameters, ventilation cooling system and heat transfer mechanism of 10 MW VSPSGM are studied. Losses in end components of VSPSGM are obtained at different locations. Fluid velocity distributions are analysed under different speeds. A coupled fluid-thermal model is developed for the end region of the 10 MW VSPSGM. Complex fluid flow and temperature distribution of end components in the VSPSGM are studied and compared at different speeds. The location of the highest temperature point is obtained. The calculated results are compared with the experimental test values. The ventilation cooling system design and accuracy of the calculation method are verified.

This paper discusses the potential core saturation issue in dry-type iron core reactors caused by power system harmonics and proposes a protection strategy based on variations in third harmonic impedance characteristics. First, an equivalent model of the dry-type iron core reactor is established by integrating its electromagnetic characteristics. Electromagnetic simulations using the COMSOL software are then conducted to analyse the dynamic trend of the reactor's equivalent inductance during core saturation. Subsequently, a power system model containing a high-voltage capacitor device was built based on Simulink. Simulations show that when the 3rd harmonic content reaches 6%, the reactor core enters a saturated state; whereas the 5th and 7th harmonics need to reach 11% and 24% content, respectively, to trigger saturation. Further analysis reveals that, compared with the fundamental wave and the 5th/7th harmonics, the 3rd harmonic impedance ratio curve exhibits unique identifiability in both single- and multifrequency harmonic scenarios: in weak and strong grid conditions, the corresponding inductance loss rate α can be accurately identified within specific ranges; in complex multifrequency harmonic environments, this identification range narrows further, with significantly improved precision. This characteristic provides a reliable basis for real-time monitoring of the saturation state of dry-type iron core reactors, confirms the effectiveness and stability of the protection method based on the 3rd harmonic impedance characteristics in complex grid environments and offers key theoretical support for the design of related protection logic.

Single-phase grounding faults (SPGFs), especially high-resistance faults, significantly weaken the electrical characteristics of active distribution networks (ADNs), thereby posing considerable challenges for faulted line selection (FLS). To address these challenges under flexible grounding conditions, this paper proposes an FLS method based on the ratio of zero-sequence current variations. By establishing the zero-sequence equivalent circuit of SPGFs in flexible grounding ADNs, the variation patterns of zero-sequence currents in both faulted and nonfaulted feeders are analysed before and after the parallel insertion of a small grounding resistor. Using a designated reference feeder, the proposed method evaluates the magnitude and phase characteristics of zero-sequence current variation ratios of other feeders relative to the reference. These features are then used to construct a reliable line selection criterion. The effectiveness of the method is validated through fault simulations carried out in PSCAD/EMTDC. Simulation results confirm that the proposed approach achieves high selection accuracy and demonstrates strong robustness against transition resistance.

This paper proposes an optimal voltage compensation method for the drop across long power cable in a motor drive system. In the proposed method the drive is utilised to compensate the voltage drop and no additional voltage regulation device is required. The method is optimised by means of vector control-based approach introduced in this paper. The independent control of voltage vectors in the d-axis and q-axis allow compensation of the amplitude drop and the phase shift. The analysis in this paper proves the minimum voltage compensation can be achieved by the independent control of the d-axis and the q-axis voltages. A dqn model of the long power cable is used in this paper which decouple the mutual coupling between the three phases. The paper starts with analysing the dependency of the voltage drop on the cable parameters and the operating power factor. Then, a brief background of the dqn power cable model is introduced. Detailed analysis of the proposed method is presented. The MATLAB simulation results show the operation from standstill slip to synchronous speed slip to verify the validity of the method in that slip range. The experimental verification is carried out by using a lumped long cable model with two different sets of inductance and resistance. It is seen that the proposed algorithm can reduce the voltage requirement by 15%–18% compared to the commonly used scalar compensation method.

Aiming at the technical problems of electromagnetic parameter analysis of large hydro generators, this paper innovatively proposes an electromagnetic torque analysis method based on the characteristics of fundamental electric quantity, with the core idea of positive and negative sequence decoupling. Under the condition of ungrounded neutral point, the method eliminates the interference of zero-sequence magnetic field and realises the decoupling of positive-sequence and negative-sequence components in the system. It models the generator as an independent positive-sequence network and negative-sequence network, decomposes the three-phase voltage and current into positive-sequence and negative-sequence components through symmetrical component transformation and establishes separate mathematical models for each sequence component to achieve independent analysis of their electromagnetic characteristics. By accurately modelling the actual connection relationship of each phase branch of the stator winding, the accurate mathematical model of the three-phase fundamental voltage, current and electromagnetic power of the stator side under the stable operation of the generator is constructed. The test results of the finite element simulation experiment platform based on 280 MVA large hydro generator show that the proposed method can effectively identify the fundamental electromagnetic torque and second harmonic electromagnetic torque under stable operating conditions, and the measured relative error range is 0.01%–9.41%, which has high engineering application accuracy.

Due to the remarkable performance, dual three-phase axial flux 33permanent magnet synchronous motors (DTP-AFPMSMs) are increasingly being adopted in the field of electric vehicles (EVs). However, the installation of position sensors limits the application scenarios of DTP-AFPMSMs owing to increased complexity, size and cost. This article proposes an innovative high-speed sensorless control method for surface-mounted DTP-AFPMSMs using an improved rotor flux observer. The proposed observer achieves precise rotor flux estimation by filtering out harmonic distortion and noise from the rotor flux of the first winding set using high-pass and low-pass filters, followed by a tracking-mode PI controller that accurately tracks the phase and amplitude of the rotor flux in the second winding set. Therefore, the proposed method can enable accurate rotor position estimation without the need for a phase-locked loop (PLL) and realise a more precise sensorless motor control. A series of simulations and experiments are carried out to validate the effectiveness of the observer, which reveals that the proposed method can effectively estimate the electrical position angle with a tiny error and presents a considerable improvement over the conventional method.

This paper examines the axial force negative stiffness of the induction and permanent magnet (PM) axial-flux machines. Simplified analytical models are used to identify the key normalised machine parameters which affect the variation of the axial force with the airgap length. The analytical results are validated against finite-element simulation and experimental results from axial force tests comparing the negative stiffness of the induction and PM axial-flux machines. Finally, the effect of load, the use of double-sided machines and tilting torque are examined.