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In this paper, RDFT(Recursive Discrete Fourier Transform) FLL(Frequency Locked Loop) based on DSC-PLL(Delayed Signal Cancellation Phase Locked Loop) is proposed for coping with frequency variation. This method shows significant performance for detection of fundamental positive sequence component voltage when the grid voltage is polluted by grid harmonics and frequency variation. The frequency tracking...
Rotor winding interturn short circuit is the main fault of synchronous electric machines, it is of great significance to the safe and stable operation of the machine to discover and handle the fault timely. In view of this, the fault positioning method of rotor turn-to-turn short circuit of synchronous machines was studied. The mathematic expression of exciting magnetomotive force (e-m.m.f.), electromotiveforce...
The thrust and levitation force of the long stator linear synchronous motor (LSLSM) are key points to evaluate the performance of the maglev train. However, it is not easy to be achieved due to the non-linear and dynamic coupling characteristics between thrust and levitation force. In this paper, the finite element analysis model of long stator linear synchronous motor is built for analyzing the thrust...
This paper presents a random space vector pulse width modulation (SVPWM) strategy for a three-phase voltage source inverter based on Field Programmable Gate Array (FPGA). It is more flexible and faster to realize randomization algorithm in FPGA than digital signal processor (DSP). What's more, it is easily extensible for multiphase driving systems with FPGA. Models in Simulink and an experiment platform...
In this paper, two dual random space vector pulse-width modulation (RSVPWM) methods, Random Switching Period-Random Zero Vector Timing SVPWM (RSP-RZVT-SVPWM) and Variable Daley-Random Zero Vector Timing SVPWM (VD-RZVT-SVPWM), are proposed to apply in five-phase inverters. The proposed RSVPWM methods can decrease the amplitudes of high harmonics and spread harmonics concentrated around switching frequency...
The efficiency of motor can be increased by optimizing stator, rotor slot design and using more materials, but there is limit within the narrow space of motor frame. Because of limited dimension, high quality material can be adapted, such as copper bar instead of aluminum bar, or low core loss Si-steel. However, adapting low core loss electrical steel does not always mean reduction of core loss. Because...
A two-dimensional (2-D) field-circuit coupled finite element model of induction motor (IM) is built. The equivalent circuit of three-phase squirrel cage rotor is modeled. Based on time-stepping finite elements analysis (T-S FEA), core loss in the stator of a no-load IM under sinusoidal and Sinusoidal Pulse Width Modulation (SPWM) excitations is studied. The rotating flux density distributions with...
This paper suggests asymmetric stator teeth design to reduce torque ripple and back EMF Total Harmonic Distortion(THD) for Interior Permanent Magnet Synchronous Machine(IPMSM). IPMSM which has 8 poles, 12 slots is analyzed in this study. From changing design parameter in stator structure, 8 comparison models are analyzed. Analysis of proposed method is carried out using Finite Element Method(FEM)...
The high temperature superconducting (HTS) cable has a wide application prospect in the future power grid because of its low loss, large capacity and friendly environment. Since without AC loss, the HTS DC cable has a longer cooling distance, and is more suitable for large capacity and long distance transmission. In the near future, with large-scale application of renewable energy, HTS DC cable is...
Two linear hall sensors are utilized to detect the mover position of permanent magnet linear motor (PMLM) in this paper. To eliminate the harmonics of the sensor signals, suboptimal multiple fading Kalman filter (SMFEKF) is utilized to estimate the mover position. The third-order harmonic is considered into the observation model of SMFEKF, and high-order harmonics are considered as measurement noise...
With the development of more/all electric aircrafts, variable frequency AC (VFAC) generation systems become popular. Dual stator-winding induction generators (DWIG) utilized in VFAC systems have the feature of the high fundamental frequency. However, the switching frequency of high power devices does not exceed 5 kHz in general, which makes carrier ratio lower. Thus, how to ensure the quality of the...
Most torque ripple reduction strategies for rotating motor are not suitable for long stator linear synchronous motor (LSLSM). In this paper, the electromagnetic force ripple reduction method for LSLSM based on the structure that the pole pitch of the mover (τm) is different from the pole pitch of the stator (τs) is analyzed. Both mathematical derivation and 2-D finite element method (FEM) are adopted...
For high power rectifiers, due to the limit restriction of the switching loss, operating at low switching frequency is necessary. In this paper, an effective approach is proposed to restrain grid harmonic current and DC-link pulsating voltage. A discrete-time domain of the complex vector current regulator combined with a synchronized PWM modulation strategies at low switching frequency are employed...
Paper introduces a coaxial magnetic gearbox with a new high-speed rotor configuration. The proposed configuration optimizes magnet volume and employs cage rotor bars in the high-speed rotor. The resulting proposed gear improves torque performance at overload condition, and utilises 5% less magnet volume in the high-speed rotor.
Since air-gap magnetic fields of brushless doubly-fed machine (BDFM) are produced by two stator windings of different pole pairs, the spatial harmonic contents of the BDFM are higher than conventional induction machines and have a considerable effect on the machine performance. To reduce the contents of main slot harmonics, the harmonic components of airgap magnetic field for the BDFM are analyzed...
According to the requirement of the power factor and the dynamic performance of the asynchronous machine tool field, an asynchronous motor inverter with active power factor correction is proposed. The proposed inverter is a 3kW asynchronous motor drive control platform. At first, the proposed single phase converter with APFC is realized by using the MATLAB/SIMULINK. Then, the boost APFC is designed...
Conventional LC filters cannot compensate effectively harmonics due to non-linear loads in a grid-connected photovoltaic (PV) system. Thus, active power filters (APF) are introduced due to its characteristics and performances, for compensation of harmonics from non-linear loads in the grid-connected photovoltaic (PV) system. This work presents a three-phase voltage-fed shunt active power filter implementation...
In this paper, a novel supply voltage harmonic mitigation method using a simple DVR without harmonic detection is proposed. In contrast to the conventional DVRs control methods, the proposed method realizes two independent control objectives at fundamental and harmonic frequencies without couplings, with the adoption of the proposed voltage controller with two independent inputs focusing on different...
This paper proposed a single-phase to three-phase converter with APF in house-service power supply of traction substation. The single phase part of converter is controlled as the rectifier, with implement of the active power filter (APF). The three phase part of converter is used as an inverter. The experiment of the step-down prototype verified the control strategy of the converter.
A Flywheel Energy Storage System (FESS) can solve the problem of randomness and fluctuation of new energy power generation. The flywheel energy storage as a DC power supply, the primary guarantee is to maintain the stability of output voltage in discharge mode, which will cause the variation of motor internal magnetic field. In this paper, taking a flywheel energy storage permanent magnet motor as...
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