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In this paper comparison of constant switching frequency carrier-based pulse-width modulation techniques for three-phase four-leg inverters is presented. Space vector, one-sixth and one-fourth third-harmonic injection and sinusoidal pulse-width modulation are compared based on output voltage total harmonic distortion, power losses and DC voltage utilization. If switching frequency of the fourth leg...
At the beginning of the sizing procedure of a switched reluctance machine (SRM), the system designer is often confronted with the task of finding an appropriate configuration for a specific application. Existing publications ([2], [3]) offer solutions to optimize the geometry of one specific configuration, but no guidance on the choice of the configuration itself. Within the scope of this paper, a...
This paper proposes a high power-density bidirectional converter for hybrid electric vehicles. A conventional HDC?? has two disadvantages. First, a large inductance is required to satisfy the inductor's ripple current because of the low switching frequency (< 20 kHz). Second, a large core size is required to prevent inductor saturation from the high current. Our present work is to achieve high...
The objective of the research is to obtain a better understanding of the feasibility of superconducting machine concepts for wave energy systems. These topologies were previously investigated by Keysan with regards to wind energy. An optimization design tool is developed in Matlab for the electrical design of the machine types. Two case studies, namely the Archimedes Wave Swing and the Oyster wave...
Voltage transients occur in a low-voltage automotive electric system due to switching on and off inductive loads. Many new loads in the system are transient in nature. These transients lead to high voltage ratings of the devices on board. They threat the safe operation of some critical electronic loads in the system. This paper begins with a review of voltage transient related standards for the low...
The silicon carbide (SiC) power semiconductor and the medium frequency transformer (MFT) are two enabling technologies that are allowing the efficiencies and power densities of power electronic converters to be pushed beyond the limits of those that have previously been possible; the solid-state transformer (SST), with its viability based in part upon the two aforementioned technologies, has much...
The present article is dealing with measures and aspects to achieve an increase in availability of electric drives. Even if the main focus will be on electric power steering application (EPS) the results can also be transferred to many other applications as well. Beginning with a brief explanation on the current state-of-the-art the use of a system attempt to collect and differentiate appropriate...
On-board bi-directional chargers for electric vehicles (EV) are important elements of smart grid infrastructure enabling peak load shaving and grid frequency/voltage support. Conventional LLC resonant converter based on-board EV charger incurs large losses in reverse mode of operation and when operating frequency deviates from the resonant frequency which is often the case as battery voltage changes...
This paper presents the analysis and evaluation of power losses in a modular multilevel flying capacitor converter (MMFCC) controlled by three different pulse width modulation techniques. A new unipolar hybrid PWM scheme, which combines phase disposed PWM (PD-PWM) and phase shifted PWM (PS-PWM), is proposed. Detailed electrical and thermal models of the single star configured FC cells are implemented...
This paper investigates the matrix converter when working as the unified power flow controller which can regulate the active reactive power flowing in a transmission line. A conventional unified power flow controller usually has a DC capacitor; this is removed in the proposed controller. This reduces the volume, improves the efficiency and lifetime, and eliminates the DC voltage control. The detailed...
This paper deals with the high efficient iron losses calculation of a yokeless and segmented-armature axial flux machine, which consists of two external rotors and an internal stator. It has many great advantages such as high efficiency, short axial length, high torque and power density due to the absence of stator yoke and the application of double layer concentrated winding. Considering the 3D magnetic...
Permanent magnet (PM) linear machines have been utilized in various applications due to their high force density, high efficiency and simple structure. In this study, the electromagnetic performances of three PM tubular machines, i.e. partitioned stator surface mounted permanent magnet (PS-SPM), partitioned stator interior permanent magnet (PS-IPM) and switched flux permanent magnet (SFPM) tubular...
This paper presents a novel method for torque ripple reduction in PMSM drives at variable speed, using a combination of angle-based repetitive control and deadbeat current control. Based on the internal model principle, repetitive control is capable to reduce periodic torque ripple by generating a compensating action that consequently need to be synchronized with the original ripple. The time to angle,...
This paper presents a case study for multi-variable and multi-modal design optimisation of a doubly fed induction generator (DFIG) based on surrogate-model optimisation algorithm. The DFIG's winding of stator and rotor are optimised to obtain higher efficiency for rewinding purposes. First, a Latin hypercube design is selected as the design of experiments to obtain sampling points. Then, the surrogate...
This paper presents a surrogate-model based optimisation method for a novel asymmetrical rotor design for easy assembly and repair of rotor windings in industrial synchronous generators. The rotor geometry of a 27.5 kVA synchronous generator is optimised to achieve the maximum efficiency and best electricity quality while maintaining the feature of rotor pole asymmetry. A surrogate modelling technique...
An angle grinder with a new Flux Reversal motor (FRM) considered in this paper has higher efficiency, lower mass and longer service time compared with analogues. The speed stabilization increases its productivity. The mathematical model of the FRM allowing us not only to calculate the motor power but to estimate the winding and core losses is described. The comparative tests have been held and its...
This paper proposes a computationally efficient analytical method, for accurate prediction of 3-dimensional (3D) eddy current loss in the rotor magnets of surface mounted permanent magnet machines considering slotting effect. Sub-domain model incorporating stator tooth tips is employed to generate the information on radial and tangential time-derivatives of 2D magnetic field (eddy current sources)...
In the past few years interest in the use of low speed permanent magnet generators for direct-drive wind turbine generator applications has increased significantly. The significant fluctuations in NdFeB magnet prices has encouraged designers to optimise magnet utilisation and to look at alternative magnet materials for wind turbine electrical generators. In this paper an analytical design model is...
This work presents the outcome of a comprehensive study that assesses the transient behaviour of two high voltage direct current (HVDC) networks with similar structures but using different converter topologies, termed two-level and half-bridge (HB) modular multilevel converter (MMC). To quantify the impact of converter topology on DC current characteristics a detailed comparative study is undertaken...
Lithium ion batteries have become a promising candidate as an energy storage in contemporary devices, especially in the automotive field. However, new challenges arise from the flat state of charge to open circuit voltage curve, which puts the Electrochemical Impedance Spectroscopy (EIS) in the lead of condition monitoring. Usually, in the EIS the Fast Fourier Transformation (FFT) is used. The FFT...
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