scholarly journals Capacitors Voltage Switching Ripple in Three-Phase Three-Level Neutral Point Clamped Inverters with Self-Balancing Carrier-Based Modulation

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3244 ◽  
Author(s):  
Manel Hammami ◽  
Gabriele Rizzoli ◽  
Riccardo Mandrioli ◽  
Gabriele Grandi
Keyword(s):  
Experimental Tests ◽  
Neutral Point ◽  
Grid Connection ◽  
Voltage Ripple ◽  
Three Phase ◽  
Capacitor Voltage ◽  
Sinusoidal Load ◽  
Almost All ◽  
Current Ripple ◽  
Voltage Switching

This paper provides a comprehensive analysis of the capacitors voltage switching ripple for three-phase three-level neutral point clamped (NPC) inverter topologies. The voltage ripple amplitudes of the two dc-link capacitors are theoretically estimated as a function of both amplitude and phase angle of output current and the inverter modulation index. In particular, peak-to-peak distribution and maximum amplitudes of the capacitor voltage switching ripple over the fundamental period are obtained. A comparison is made considering different carrier-based pulse-width modulations in the case of almost all sinusoidal load currents, representing either grid connection or passive load with a negligible current ripple. Based on the voltage switching ripple requirements of capacitors, a simple and effective original equation for a preliminary sizing of the capacitors has been proposed. Numerical simulations and experimental tests have been carried out in order to verify the analytical developments.

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

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1430
Author(s):  
Aleksandr Viatkin ◽  
Riccardo Mandrioli ◽  
Manel Hammami ◽  
Mattia Ricco ◽  
Gabriele Grandi
Keyword(s):  
Numerical Simulations ◽  
Pulse Width Modulation ◽  
Neutral Line ◽  
Experimental Tests ◽  
Performance Comparison ◽  
Design Parameters ◽  
Switching Frequency ◽  
Three Phase ◽  
Ac Current ◽  
Current Ripple

This paper presents a comprehensive study of peak-to-peak and root-mean-square (RMS) values of AC current ripples with balanced and unbalanced fundamental currents in a generic case of three-phase four-leg converters with uncoupled AC interface inductors present in all three phases and in neutral. The AC current ripple characteristics were determined for both phase and neutral currents, considering the sinusoidal pulse-width modulation (SPWM) method. The derived expressions are simple, effective, and ready for accurate AC current ripple calculations in three- or four-leg converters. This is particularly handy in the converter design process, since there is no need for heavy numerical simulations to determine an optimal set of design parameters, such as switching frequency and line inductances, based on the grid code or load restrictions in terms of AC current ripple. Particular attention has been paid to the performance comparison between the conventional three-phase three-leg converter and its four-leg counterpart, with distinct line inductance values in the neutral wire. In addition to that, a design example was performed to demonstrate the power of the derived equations. Numerical simulations and extensive experimental tests were thoroughly verified the analytical developments.

scholarly journals Analysis of Input Voltage Switching Ripple in Three-Phase Four-Wire Split Capacitor PWM Inverters

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5076 ◽  
Author(s):  
Manel Hammami ◽  
Riccardo Mandrioli ◽  
Aleksandr Viatkin ◽  
Mattia Ricco ◽  
Gabriele Grandi
Keyword(s):  
Numerical Simulations ◽  
Comprehensive Evaluation ◽  
Experimental Tests ◽  
Input Voltage ◽  
Switching Voltage ◽  
Two Phase ◽  
Voltage Ripple ◽  
Battery Chargers ◽  
Three Phase ◽  
Split Capacitor

Three-phase, four-wire split capacitor inverters are currently employed in many applications, such as photovoltaic systems, battery chargers for electric vehicles, active power filters, and, in general, in all grid-tied applications that deal with possible grid voltage and/or current unbalances. This paper provides a comprehensive evaluation of the capacitor-switching voltage ripple and dc-link switching voltage ripple for the three-phase, four-wire, split capacitor inverters. Specifically, analytical formulations of the peak-to-peak and rms values of the voltage ripples are originally pointed out in this paper and determined in the case of balanced three-phase and unbalanced (two-phase and single-phase) output (ac) currents. The obtained results can help in designing the considered inverter and sizing of the dc-link capacitors. Reference is made to the sinusoidal PWM modulation and sinusoidal three-phase output currents with an almost unity power factor, representing a grid-connected application. Extensive numerical simulations have been carried out to thoroughly verify all the analytical developments presented in this paper. Furthermore, some experimental tests, having balanced output currents on the ac side, have been accomplished, validating numerical simulations and analytical developments.

Capacitor voltage balancing of a three‐phase neutral‐point clamped bi‐directional rectifier using optimised switching sequences

2013 ◽  
Vol 6 (6) ◽  
pp. 1209-1219 ◽  
Author(s):  
Abdul Hamid Bhat ◽  
Nitin Langer ◽  
Deepak Sharma ◽  
Pramod Agarwal
Keyword(s):  
Neutral Point ◽  
Voltage Balancing ◽  
Three Phase ◽  
Capacitor Voltage

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

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 116
Author(s):  
Aleksandr Viatkin ◽  
Riccardo Mandrioli ◽  
Manel Hammami ◽  
Mattia Ricco ◽  
Gabriele Grandi
Keyword(s):  
Smart Grids ◽  
Harmonic Distortion ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Voltage Source ◽  
Switching Frequency ◽  
Voltage Source Converters ◽  
Three Phase ◽  
Ac Current ◽  
Current Ripple

Three-phase four-leg voltage-source converters have been considered for some recent projects in smart grids and in the automotive industry, projects such as on-board electric vehicles (EVs) chargers, thanks to their built-in ability to handle unbalanced AC currents through the 4th wire (neutral). Although conventional carrier-based modulations (CBMs) and space vector modulations (SVMs) have been commonly applied and extensively studied for three-phase four-leg voltage-source converters, very little has been reported concerning their pollution impact on AC grid in terms of switching ripple currents. This paper introduces a thorough analytical derivation of peak-to-peak and RMS values of the AC current ripple under balanced and unbalanced working conditions, in the case of three-phase four-leg converters with uncoupled AC-link inductors. The proposed mathematical approach covers both phase and neutral currents. All analytical findings have been applied to two industry recognized CBM methods, namely sinusoidal pulse-width modulation (PWM) and centered PWM (equivalent to SVM). The derived equations are effective, simple, and ready-to-use for accurate AC current ripple calculations. At the same time, the proposed equations and diagrams can be successfully adopted to design the conversion system basing on the grid codes in terms of current ripple (or total harmonic distortion (THD)/total demand distortion (TDD)) restrictions, enabling the sizing of AC-link inductors and the determination of the proper switching frequency for the given operating conditions. The analytical developments have been thoroughly verified by numerical simulations in MATLAB/Simulink and by extensive experimental tests.

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