Topic
Three-phase
About: Three-phase is a research topic. Over the lifetime, 16801 publications have been published within this topic receiving 159477 citations.
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TL;DR: Analysis of the current ripple of a three-phase PWM converter with general PWM methods for the design and control of this kind of converter shows that discontinuous PWM could generate obviously bigger current ripples than space vector PMW for both peak and rms values with the same conditions.
Abstract: The three-phase pulsewidth-modulation (PWM) converter is one of the most widely used topologies for power conversion In order to design PWM methods, the influence of PWM methods on the current ripple is needed This paper studies the current ripple of a three-phase PWM converter with general PWM methods for the design and control of this kind of converter The current ripple is analyzed with eight different Thevenin equivalent circuits for the eight different voltage vectors Then, the current-ripple slope and effective time could be achieved for every period The current ripple could be predicted with both peak and rms values Analytical predicted results show that discontinuous PWM could generate obviously bigger current ripples than space vector PMW for both peak and rms values with the same conditions Simulation and experiments are built to verify the analytical results, proving that the theoretical prediction is valid This analysis provides the basis for the design and control of the PWM method for converters
97 citations
15 Jun 2003
TL;DR: In this article, the authors presented a 2 kW three-phase dual active bridge converter (DAB3) which converts power between 42 V and 300 V and is easily scalable up to 20 kW.
Abstract: This paper presents a 2 kW three-phase dual active bridge converter (DAB3) which converts power between 42 V and 300 V and is easily scalable up to 20 kW. The DAB3 has been selected for this application based on detailed simulations comparing different suitable topologies. The circuits investigated in this paper can operate in a soft-switching manner enabling a reduction in device switching losses and therewith an increase in switching frequency. Candidate topologies under investigation are the serial resonant converter (SR), the single-phase dual active bridge (DAB1) and the three phase dual active bridge (DAB3). Key-features are the galvanic isolation, reduced cooling costs, and the capability of transferring energy over a wide voltage range.
97 citations
TL;DR: In this paper, the second-order torque harmonics produced by dc-capacitor voltage fluctuations are first demonstrated, and a very simple compensation method is presented by introducing a novel nonorthogonal coordinate transformation.
Abstract: As a result of their reduced number of switches, three-phase four-switch (TPFS) inverters are generally applied as cost-reduction topologies for permanent magnet synchronous motor (PMSM) drives. However, the torque ripples of PMSM severely deteriorate the performance and reliability of the entire system. Hence, comprehensive considerations for torque ripple reduction, including high- and low-frequency torque ripples, are elaborated considering TPFS inverter-fed PMSM drives. The second-order torque harmonics produced by dc-capacitor voltage fluctuations are first demonstrated, and a very simple compensation method is presented by introducing a novel nonorthogonal coordinate transformation. Then, to evaluate the effects on the high-frequency torque ripples of space vector modulation (SVM) schemes, three SVM schemes for TPFS inverter-fed PMSM drives are assessed based on the torque ripple root-mean-square value. Consequently, the preferred SVM scheme is obtained for high-frequency torque ripple minimization. Moreover, the linear modulation range of the TPFS inverter-fed PMSM drive is derived considering capacitor voltage fluctuations, therein avoiding the low-frequency torque ripples caused by overmodulation. Meanwhile, an adaptive capacitor voltage offset suppression method is proposed to fully exploit the dc-link voltage. The experimental results demonstrate the validation and effectiveness of the proposed analysis and methods for torque ripple reduction.
97 citations
TL;DR: The proposed fault-tolerant MPDPC with power compensation method ensures the continuous and reliable operation of the bidirectional ac/dc converter with high power quality and validate the proposed control strategy under symmetrical unbalanced grid voltages with switch device faults.
Abstract: The bidirectional ac/dc converter is widely used to realize the power conversion between ac and dc microgrid, but the faults of switch devices and unbalanced grid voltages may lead to the decline of power quality and affect normal operation of the converter. The four-switch three-phase (FSTP) fault-tolerant structure is reconstructed from a six-switch three-phase structure with switch device fault. In order to reduce harmonic currents and output power fluctuations under unbalanced grid voltages, finite states model predictive direct power control (MPDPC) with power compensation method is proposed for FSTP structure and predictive power model of the bidirectional FSTP ac/dc converter is established. The power compensation values are expressed by grid voltages and their quadrature signals that lagging 90 electrical degrees in the αβ stationary coordinate system. Compared with the conventional method, phase-locked loop, pulse width modulation, and complex positive-/negative-sequence extraction of grid voltage are not required. Ripples of active power or reactive power under unbalanced grid voltages are eliminated. The proposed fault-tolerant MPDPC with power compensation method ensures the continuous and reliable operation of the bidirectional ac/dc converter with high power quality. Simulation and experimental results are presented to validate the proposed control strategy under symmetrical unbalanced grid voltages with switch device faults.
96 citations
TL;DR: In this paper, a recursive discrete Fourier transform (DFT) algorithm is used to calculate voltage and current phase and magnitude, real and reactive power, frequency, and impedance.
Abstract: State-of-the-art technology now permits measurement and analysis of power system performance on a scale not previously possible. Synchronized sampling, derived from the GPS (Global Positioning System), and high accuracy sigma-delta analog-to-digital converters form the basis for a system that can measure the state of the power system at a given instant over any area. Samples are acquired 12 times per cycle and are processed by a recursive discrete Fourier transform (DFT) algorithm. This produces the magnitude and angle of the input signal for each sample. The resulting phasors can be combined to produce a positive sequence phasor for a set of three phase inputs. The positive sequence quantities can be used to calculate voltage and current phase and magnitude, real and reactive power, frequency, and impedance. Since the positive sequence parameters are acquired at the same instant (within 1 microsecond), the state of the system at the measured nodes is known at the sample time. Applications to fault recording, disturbance recording, transmission and generation modelling verification, and power system stabiliser testing, are discussed. >
96 citations