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.

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 Equivalent Inductance of Three-phase Induction Motors in the Switching Frequency Range

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 120 ◽  
Author(s):  
Milan Srndovic ◽  
Rastko Fišer ◽  
Gabriele Grandi
Keyword(s):  
Induction Motors ◽  
Harmonic Distortion ◽  
Voltage Source ◽  
Switching Frequency ◽  
Frequency Range ◽  
Leakage Inductance ◽  
Squirrel Cage ◽  
Three Phase ◽  
Ripple Amplitude ◽  
Current Ripple

The equivalent inductance of three-phase induction motors is experimentally investigated in this paper, with particular reference to the frequency range from 1 kHz to 20 kHz, typical for the switching frequency in inverter-fed electrical drives. The equivalent inductance is a basic parameter when determining the inverter-motor current distortion introduced by switching modulation, such as rms of current ripple, peak-to-peak current ripple amplitude, total harmonic distortion (THD), and synthesis of the optimal PWM strategy to minimize the THD itself. In case of squirrel-cage rotors, the experimental evidence shows that the equivalent inductance cannot be considered constant in the frequency range up to 20 kHz, and it considerably differs from the value measured at 50 Hz. This frequency-dependent behaviour can be justified mainly by the skin effect in rotor bars affecting the rotor leakage inductance in the considered frequency range. Experimental results are presented for a set of squirrel-cage induction motors with different rated power and one wound-rotor motor in order to emphasize the aforesaid phenomenon. The measurements were carried out by a three-phase sinusoidal generator with the maximum operating frequency of 5 kHz and a voltage source inverter operating in the six-step mode with the frequency up to 20 kHz.

MATHEMATICAL MODELING OF ANALOG CONTROLLED VOLTAGE SOURCE CONVERTERS FOR IMPROVED DYNAMIC RESPONSE

1998 ◽  
Vol 08 (04) ◽  
pp. 483-496 ◽  
Author(s):  
M. N. GITAU ◽  
I. R. SMITH ◽  
J. G. KETTLEBOROUGH
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Voltage Source ◽  
Current Loop ◽  
Voltage Source Converter ◽  
Switching Frequency ◽  
Voltage Source Converters ◽  
Phase Voltage ◽  
Nonlinear Loads ◽  
Three Phase

Increases in the occurrence of nonlinear loads have resulted in the need to reduce or minimize the levels of harmonic currents being injected into the power supply. As a consequence, active current waveshaping and pulse-width modulation have now replaced conventional phase-controlled and diode bridge rectifiers in many applications. In this paper, mathematical models are developed for the power circuits of analog controlled single-phase and three-phase voltage source converters, and then used to analyse the performance of current- and voltage-control loops for the converters. Analytical expressions are derived for the gains and time constants of the current and voltage controllers, and it is shown that the bandwidth of the current-loop is a function of the switching frequency, and that of the voltage-loop is a function of the DC-busbar capacitance and the voltage filter cut-off frequency. To illustrate the application of the models, simulation results are presented from investigations into the control of a 5 kW single-phase voltage-source converter and a 100 kW three-phase boost converter.

Utilization of Self-Excited Three-Phase Induction Generator System

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Basil Saied ◽  
Hasan Mohammed
Keyword(s):  
Harmonic Distortion ◽  
Active Power ◽  
Modulation Index ◽  
Voltage Source ◽  
Induction Generator ◽  
Switching Frequency ◽  
Prime Mover ◽  
Generator System ◽  
Dc Voltage ◽  
Three Phase

In this paper the analysis of a three phase self-excited induction generator system under transient and steady states with various load conditions are presented. In rare area where assumed no national grid is present, but hydro or wind energy may be available a cheap prime mover, such as micro hydro or wind turbine may be applied, which has fluctuating speed. In order to obtain self-excitation, a voltage source inverter based on sinusoidal pulse width modulation  strategy has been proposed. The generated voltage and frequency are regulated by adjusting modulation index value. The value of modulation index  depends also on the DC voltage level obtained from  batteries or solar panels. The proposed system has been also examined without main dc power source , but with the existence of bank capacitor located at the dc link side of the inverter, in this case  the generated active power should be equal to/or greater than the required active load power. DC chopper load has thus been utilized to absorb the extra active power, this will control the DC voltage across the capacitor while modulation index  will control the system AC  output voltage. The generated voltage waveform contains harmonic orders around and higher than the switching frequency, therefore three-phase high passive filter has been used to eliminate the harmonics effects. As a result the machine terminal voltage and frequency values are regulated and maintained constant for different types of loads at different prime mover speed cases. In all these cases, total harmonic distortion values are within the standard values.

scholarly journals Optimal design of a single-phase APF based on PQ theory

2020 ◽  
Vol 11 (3) ◽  
pp. 1360
Author(s):  
Dur Muhammad Soomro ◽  
Sager K. Alswed ◽  
Mohd Noor Abdullah ◽  
Nur Hanis Mohammad Radzi ◽  
Mazhar Hussain Baloch
Keyword(s):  
Optimal Design ◽  
Power Loss ◽  
Single Phase ◽  
Reactive Power ◽  
Harmonic Distortion ◽  
Voltage Source ◽  
Switching Frequency ◽  
Shunt Active Power Filter ◽  
Current Controller ◽  
Three Phase

The instantaneous active and reactive power (PQ) theory is one of the most widely used control theory for shunt active power filter (SAPF), which can be implemented in single-phase and three-phase systems. However, the SAPF with PQ theory still had ability to improve to become more efficient. This paper presents the optimal design of a single-phase SAPF in terms of reducing the current harmonic distortion and power loss in voltage source inverter (VSI) controlled with the semiconductor switching devices IGBT, MOSFET and Hybrid (combination of IGBT and MOSFET). In order to reduce the switching frequency and power loss of VSI, instead of using single-band hysteresis current controller (HCC), double-band HCC (DHCC) and triple-band HCC (THCC) is used in the SAPF. The designed SAPF is tested with different non-linear loads to verify the results by using MATLAB Simulink.

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