A novel 3-phase AC current control technique with fast response and high accuracy

2002 ◽  
Author(s):  
Jong-Woo Choi ◽  
Seung-Ki Sul
Keyword(s):  
Fast Response ◽  
High Accuracy ◽  
Current Control ◽  
Control Technique ◽  
Ac Current

scholarly journals Reduced Switch Multilevel Inverter based STATCOM

2020 ◽  
Vol 6 (5) ◽  
pp. 117-121
Author(s):  
Akshay Kadu
Keyword(s):  
Direct Current ◽  
Power Factor ◽  
Control Method ◽  
Digital Simulation ◽  
Fast Response ◽  
Current Control ◽  
Multilevel Inverter ◽  
Control Technique ◽  
Basic Unit ◽  
Direct Current Control

This paper presents an application of reduced switch multilevel inverter topology to STACOM. This topology consists of basic unit in which two switches are connected in series and one H-bridge unit. Multilevel inverter is beneficial in terms of reliability and improved output quality. Multilevel inverter have only drawback of higher number of switches. This reduced switch topology has less number of switches as compared to conventional Cascaded H Bridge Inverter. Compared to direct control method, indirect control method is simple but due to fast response and precise control, direct current control method is quite effective. In this work STACOM is implemented to improve the Power factor of the power system. An extensive digital simulation of the recommended STATCOM and its controller is carried out using MATLAB/SIMULINK software to study system performance. Simulation results prove that using Direct current control technique overall power factor is improved.

scholarly journals Versatile AC Current Control Technique for a Battery Using Power Converters

Batteries ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 47
Author(s):  
S. M. Rakiul Islam ◽  
Sung-Yeul Park
Keyword(s):  
Input Voltage ◽  
Open Circuit ◽  
Current Control ◽  
Current Injection ◽  
Control Technique ◽  
Feedback Gain ◽  
Stable Operation ◽  
Offset Voltage ◽  
Internal Impedance ◽  
Ac Current

Although a battery is a DC device, AC current is often necessary for testing, preheating, impedance spectroscopy, and advanced charging. This paper presents a versatile control technique to inject AC current to a battery. Synchronous buck and H-bridge topologies are operated in bidirectional mode and controlled by uni-polar and bi-polar pulse width modulation techniques for the AC current injection. The input and output passive circuits are specially designed considering AC current and the properties of the battery. A controller is proposed considering a small internal impedance, small AC ripple voltage, and variable DC offset voltage of a battery. The controller is capable of maintaining stable operation of AC current injection in two power quadrant within a small DC voltage boundary of a battery. The controller is comprised of a feedback compensator, a feedforward term, and an estimator. The feedback gain is designed considering the internal impedance. The feedforward gain is designed based on estimated open circuit battery voltage and input voltage. The open circuit voltage estimator is designed based on filters and battery model. For validation, AC current is injected to a Valence U-12XP battery. The battery is rated for 40 Ah nominal capacity and 13.8 V nominal voltage The controller successfully injected AC current to a battery with +10 A, 0 A and −10 A DC currents. The magnitude and frequency of the AC current was up to 5 A and 2 kHz respectively.

scholarly journals Comparative Study of Classical and MPC Control for Single-Phase MMC Based on V-HIL Simulations

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3230
Author(s):  
Milovan Majstorovic ◽  
Marco Rivera ◽  
Leposava Ristic ◽  
Patrick Wheeler
Keyword(s):  
Single Phase ◽  
Current Control ◽  
Superior Performance ◽  
Control Methods ◽  
Reference Tracking ◽  
Voltage Balancing ◽  
Current Reference ◽  
Circulating Current ◽  
Ac Current ◽  
Classical Control

The operation of single-phase Modular Multilevel Converter (MMC) is analyzed in the paper. A mathematical model of the converter is developed and described, based on which the structure and selection of parameters for Classical Control and Optimal Switching State Model Predictive Control (OSS-MPC) are defined. Additionally, the procedure for the determination of circuit parameters, such as submodule capacitance and arm inductance, is described and carried out. The listed control methods are designed and evaluated in Virtual Hardware-in-the-Loop together with single-phase MMC power circuit, regarding three control objectives: AC current control, voltage balancing control and circulating current control. Control methods are evaluated for both steady-state and transient performance and compared based on nine criteria: AC current reference tracking, THD of AC current and voltage, submodule capacitor voltage balancing, total submodule voltage control, circulating current magnitude and THD, number of control parameters and computational complexity. This is the first time that a fair comparison between Classical Control and MPC is considered in literature, resulting in superior performance of both control methods regarding four different criteria and the same performance regarding AC current reference tracking.

Extended Mobility Carried Out with a Double Hexapod Robot

2010 ◽  
Vol 166-167 ◽  
pp. 271-276 ◽  
Author(s):  
Mihai Margaritescu ◽  
Ana Maria Eulampia Ivan ◽  
Vlad Vaduva ◽  
Cornel Brisan
Keyword(s):  
Fast Response ◽  
High Accuracy ◽  
Positioning System ◽  
Hexapod Robot ◽  
Parallel Kinematics ◽  
High Stiffness ◽  
Serial Robots ◽  
Visual Comparison ◽  
Operating Space

The double hexapod robot consists in two staged hexapod platforms – Stewart Gough platforms - combining in a certain measure the advantages of the robots with parallel kinematics and of the serial robots: high accuracy, high stiffness, fast response and small dimensions, having an extended operating space. Different modelling and construction aspects were described in few previous articles. Some examples of trajectories generated with this positioning system are now presented to illustrate its mobility, as well as the workspaces for one and two hexapods in order to make possible a visual comparison between the two volumes.

scholarly journals Disturbance-Observer-Based Model Predictive Control for Battery Energy Storage System Modular Multilevel Converters

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2285 ◽  
Author(s):  
Yantao Liao ◽  
Jun You ◽  
Jun Yang ◽  
Zuo Wang ◽  
Long Jin
Keyword(s):  
Energy Storage ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Current Control ◽  
Multilevel Converters ◽  
Battery Energy Storage ◽  
Circulating Current ◽  
Modular Multilevel Converters ◽  
Ac Current ◽  
Battery Energy

Although the traditional model predictive control (MPC) can theoretically provide AC current and circulating current control for modular multilevel converters (MMCs) in battery energy storage grid-connected systems, it suffers from stability problems due to the power quality of the power grid and model parameter mismatches. A two discrete-time disturbance observers (DOBs)-based MPC strategy is investigated in this paper to solve this problem. The first DOB is used to improve the AC current quality and the second enhances the stability of the circulating current control. The distortion and fluctuation of grid voltage and inductance parameter variation are considered as lump disturbances in the discrete modeling of a MMC. Based on the proposed method, the output prediction is compensated by disturbance estimation to correct the AC current and circulating current errors, which eventually achieve the expected tracking performance. Moreover, the DOBs have a quite low computational cost with minimum order and optimal performance properties. Since the designed DOBs work in parallel with the MPC, the control effect is improved greatly under harmonics, 3-phase unbalance, voltage sag, inductance parameter mismatches and power reversal conditions. Simulation results confirm the validity of the proposed scheme.

Implementation of Single-Phase Two-Switch Midpoint Unidirectional Multilevel Converter System

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Open Loop ◽  
Current Control ◽  
Control Technique ◽  
Control Scheme

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.

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