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This paper presents a new application of modular multilevel cascaded converters (MMCC) for combined active harmonic current elimination and reactive power compensation in a power distribution line. A technique for simultaneous extracting harmonic components and reactive element in the load current is presented. A novel voltage control scheme for balancing the module intra-cluster capacitor voltages...
This paper presents a new algorithm which employs morphological filter and instantaneous reactive power theory for phasor measurement. A preprocessor is proposed to removes the decaying DC component from the input signal with a delay of two samples. The effects of sampling rate, time constant, frequency shift, harmonics and fault inception angle on the performance of the proposed algorithm have been...
This paper presents a simulation study for a built prototype of modular multi-level flying capacitor cascade converter as a STATCOM. The converter modulation scheme applied is based on Phase Shifted PWM and the two scenarios which require compensation are investigated to verify this topology. The two scenarios are PCC voltage regulation and unity power factor correction through reactive power compensation...
A well-known issue with existing power systems is rapid and accurate synchronisation to grid voltages when the system is unbalanced under grid fault conditions and corrupted with harmonics. This paper presents a novel phase locked loop technique for grid synchronisation technique using the energy operator. A comparative study is undertaken to investigate the accuracy and robustness of this technique...
The accurate detection and location of a fault is crucial for power systems applications such as protective relaying and phasor measurement. As fault signals have unique mathematical expressions, this paper proposes a computational intelligence based method to estimate the parameters of the fault signal towards the minimum difference between the input signal and the reconstructed one. The optimization...
Permanent magnet synchronous motors (PMSMs) with salient rotor structure are attractive in the applications where high power density and high efficiency is of importance[1]. However, with the increasing of power density and rotating speed, acoustic noise and vibration problem [2] caused by electromagnetic (E.M.) force wave is very serious. But, the existing literatures [3-4] mainly research the non-salient...
Experimental results will be presented of a frequency tunable gyrotron backward wave oscillator (gyro-BWO). A helically corrugated interaction region (HCIR) was used to allow efficient interaction over a wide frequency band at the second harmonic of the electron cyclotron frequency without parasitic output [1-5]. The gyro-BWO generated a maximum output power of 12 kW when driven by a 40 kV, 1.5 A,...
An online harmonic estimation technique is proposed based on lifting wavelet transforms. The effectiveness of this technique is successfully verified in the paper through analyzing the current samples supplied to a practical building network which are unbalanced and corrupted with noise. Combining with a novel synchronization technique based on the energy operator principle, this scheme is applied...
Theoretical calculation, numerical simulation and experimental development of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. The cusp gun generated a 40 keV, 1.5 A axis-encircling electron beam. The maximum output of the gyro-TWA was predicted to be 5 kW with a 3 dB frequency bandwidth of 90–100 GHz and a saturated gain of 37 dB. The latest experimental...
A thermionic cusp electron gun has been designed, numerically optimized and experimentally measured and is presented. A 40 kV, 1.5 A annular axis-encircling electron beam has been simulated to generate a beam with low velocity and alpha spreads. The electron gun performance has been verified through experiments and the results are given.
Harmonic characteristics of a number of widely used appliances are investigated. Their cumulative effect on a 3-phase 4-wire distribution network, in terms of severity of harmonic disturbance and current unbalance, is explored. This data is used in designing an active power filter based on a 3-phase 4-leg flying capacitor multilevel converter to eliminate the harmonics and current unbalance. The controller...
In this paper the 3-level integration PWM is developed to a simplified generalized PWM algorithm which can be used to control higher level photovoltaic (PV) inverters. The proposed algorithm is implemented practically by using eZdsp™ F28335 to control the multi-level DC-link inverter and to maintain the operation of input PV sources at their maximum power point (MPP). The inverter has been tested...
A strategy is presented for the control of a 4-limb flying-capacitor multi-level inverter (FCMI) as an active power filter for unbalanced load conditions. Improved reference tracking is achieved using a modified deadbeat controller, and a naturally-balanced 3DPWM technique enables sensor-less flying-capacitor voltage control. Simulation results show the effectiveness of the proposed scheme.
A 390 GHz harmonic gyrotron based on a cusp electron gun was designed to operate on a TE71 mode and the 7th cyclotron harmonic of a large orbit electron beam. This beam is produced by a cusp electron gun with a voltage of 40 keV, a current of 1.5 A and an adjustable velocity ratio from 1 to 3. Smooth cylindrical waveguide was studied and built as the interaction cavity. The relationship between the...
The experimental demonstration of a gyrotron backward wave oscillator (gyro-BWO) using a cusp electron gun and helically corrugated waveguide will be presented. Operating in the W-band frequency range the gyro-BWO is predicted to output ~10 kW with a frequency tuning range of 85-104 GHz at 18% electronic efficiency before the energy recovery. The annular axis-encircling electron beam has been experimentally...
The majority of studies in saturation nonlinearities making use of periodic input signals and signal noise ratio (SNR) measures indicate the possibility of SNR gains due to stochastic resonance (SR). The paper points out that for such circumstances, the SNR measure discards some statistical information due to the saturation. When the shape of input signals is required at the output of the saturation...
The paper presents a switching pattern selection scheme for the control of a multilevel flying capacitor inverter. The scheme reduces capacitor voltage fluctuation without using voltage feedback. The method is developed for sinusoidal voltage generation using the selective harmonic elimination (SHE) technique and was compared favorably with the result when voltage feedback was used.. The result of...
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