AC Current - DOAJ

A Comprehensive AC Current Ripple Analysis and Performance Enhancement via Discontinuous PWM in Three-Phase Four-Leg Grid-Connected Inverters

A complete investigation of the ac output current ripple in four-leg voltage source inverters considering multiple modulation options is included. In the whole basic period, current ripple envelopes and peak-to-peak profiles have been identified, and a robust approach of providing the latest ripple rms has been established, most of which are as a result of the modulation index. Moreover, the average switching frequency and switching losses are measured, determining which PWM technique achieves minimum output current ripple within different assumptions.

Source link: https://doi.org/10.3390/en13174352

AC Current Ripple in Three-Phase Four-Leg PWM Converters with Neutral Line Inductor

In a general case of three-phase converters with uncoupled AC interface inductors present in all three phases and in neutral, this paper presents a comprehensive analysis of peak-to-peak and root-mean-square values of AC current ripples with balanced and unbalanced fundamental currents. Considering the sinusoidal pulse-width modulation method, both phase and neutral currents were determined for both phase and neutral currents. Particular attention has been paid to the comparison between the three-phase three-leg converter and its four-leg counterpart, with different line inductance values in the neutral wire.

Source link: https://doi.org/10.3390/en14051430

High Sensitivity Differential Giant Magnetoresistance (GMR) Based Sensor for Non-Contacting DC/AC Current Measurement

This paper discusses the construction and usage of a high-sensitivity giant magnetoresistance based current sensor with a wide variety of applications. The unique of our approach is that we used a two-different measurement system based on commercial GMR sensors, as well as an adjustable biasing system to normalize the field response of the instrument. The new measurement system can be used in DC and 150 mA in AC up to 4 A by a single unit, with a broad current measurement range from 75 mA to 4 A in AC. U22124. 59 A/U2050B0C, a high resistance to external magnetic fields, low hysteresis effects of 40 mA, and a temperature drift of the offset of about 0. 0272 to 0. 0307 V/A, a constant change of the current to be measured is flowing due to the fact that the sensors are polarized and positioned above the U-shaped conductive band through which the current to be measured is flowing, and u00b0C.

Source link: https://doi.org/10.3390/s20010323

AC Current Ripple Harmonic Pollution in Three-Phase Four-Leg Active Front-End AC/DC Converter for On-Board EV Chargers

Although conventional carrier-based modulations and space vector modulations have been widely used and extensively researched for three-phase four-leg voltage-source converters, little has been reported on their environmental impact on the AC grid in terms of changing ripple currents. In the case of three-phase four-leg converters with uncoupled AC-link inductors, this paper presents a comprehensive investigation of the AC current ripple's peak-to-peak and RMS values of the AC current ripple under balanced and unbalanced working conditions. At the same time, the suggested equations and diagrams can be used to create the conversion device based on current ripple guidelines, allowing the sizing of AC-link inductors and the determination of the correct switching frequency for the respective operating conditions.

Source link: https://doi.org/10.3390/electronics10020116

Low Field Optimization of a Non-Contacting High-Sensitivity GMR-Based DC/AC Current Sensor

Many applications require galvanic isolation between the circuit where the current is flowing and the measurement unit. This essentially amounts to a planar coil that would greatly enhance the usable magnetic field detected by the GMR sensor. An experimental device is being developed for calculating the magnetic field generated by the current in the GMR sensing area, which resulted in a significant rise in sensitivity up to 13 times compared to a single biased sensor. DC and AC currents range from 2 to 23. 19 mV/mA, with a detection limit of 100 % to 150 kHz in DC and 100 to 300 mB, respectively.

Source link: https://doi.org/10.3390/s21072564

Analysis of Stationary- and Synchronous-Reference Frames for Three-Phase Three-Wire Grid-Connected Converter AC Current Regulators

Unbalance and distortion on the voltage waveforms at the terminals of a grid-connected inverter's terminals disrupt the product's current output voltages, according to the current state of the art. This paper compares AC linear current regulators for three-phase three-wire voltage source converters with three different reference frames, including natural, orthogonal stationary, and orthogonal synchronous. The control system developed in the dq-frame exhibits the highest computational cost and inferior results under negative-sequence voltage fluctuations, as shown by the comparison frames, but it has better results under positive-sequence voltages.

Source link: https://doi.org/10.3390/en14248348

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