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

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8348
Author(s):  
Israel D. L. Costa ◽  
Danilo I. Brandao ◽  
Lourenço Matakas Junior ◽  
Marcelo G. Simões ◽  
Lenin M. F. Morais
Keyword(s):  
Steady State ◽  
Reference Frames ◽  
Computational Cost ◽  
Transient Behavior ◽  
Computational Effort ◽  
Superior Performance ◽  
Positive Sequence ◽  
Voltage Source ◽  
Three Phase ◽  
Grid Connected Inverter

The current state of the art shows that unbalance and distortion on the voltage waveforms at the terminals of a grid-connected inverter disturb its output currents. This paper compares AC linear current regulators for three-phase three-wire voltage source converters with three different reference frames, namely: (1) natural (abc), (2) orthogonal stationary (αβ), and (3) orthogonal synchronous (dq). The quantitative comparison analysis is based on mathematical models of grid disturbances using the impedance-based analysis, the computational effort assessment, as well as the steady-state and transient performance evaluation based on experimental results. The control scheme devised in the dq-frame has the highest computational effort and inferior performance under negative-sequence voltage disturbances, whereas it shows superior performance under positive-sequence voltages among the reference frames evaluated. In contrast, the stationary natural frame abc has the lowest computational effort due to its straightforward implementation, with similar results in terms of steady-state and transient behavior. The αβ-frame is an intermediate solution in terms of computational cost.

scholarly journals Study and Application of Intelligent Sliding Mode Control for Voltage Source Inverters

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2544 ◽  
Author(s):  
En-Chih Chang
Keyword(s):  
Steady State ◽  
Sliding Mode Control ◽  
Digital Signal Processor ◽  
Sliding Mode ◽  
Transient Behavior ◽  
Voltage Source ◽  
Accurate Estimation ◽  
Inference System ◽  
Mode Control ◽  
State Error

In this paper, an intelligent sliding mode controlled voltage source inverter (VSI) is developed to achieve not only quick transient behavior, but satisfactory steady-state response. The presented approach combines the respective merits of a nonsingular fast terminal attractor (NFTA) as well as an adaptive neuro-fuzzy inference system (ANFIS). The NFTA allows no singularity and error states to be converged to the equilibrium within a finite time, while conventional sliding mode control (SMC) leads to long-term (infinite) convergent behavior. However, there is the likelihood of chattering or steady-state error occurring in NFTA due to the overestimation or underestimation of system uncertainty bound. The ANFIS with accurate estimation and the ease of implementation is employed in NFTA for suppressing the chatter or steady-state error so as to improve the system’s robustness against uncertain disturbances. Simulation results display that this described approach yields low distorted output wave shapes and quick transience in the presence of capacitor input rectifier loading as well as abrupt connection of linear loads. Experimental results conducted on a 1 kW VSI prototype with control algorithm implementation in Texas Instruments DSP (digital signal processor) support the theoretic analysis and reaffirm the robust performance of the developed VSI. Because the proposed VSI yields remarkable benefits over conventional terminal attractor VSIs on the basis of computational quickness and unsophisticated realization, the presented approach is a noteworthy referral to the designers of correlated VSI applications in future, such as DC (direct current) microgrids and AC (alternating current) microgrids, or even hybrid AC/DC microgrids.

scholarly journals Enhanced Performance Modified Discontinuous PWM Technique for Three-Phase Z-Source Inverter

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 578 ◽  
Author(s):  
Hossameldin ◽  
Abdelsalam ◽  
Ibrahim ◽  
Williams
Keyword(s):  
Current Source ◽  
Operating Conditions ◽  
Single Stage ◽  
Superior Performance ◽  
Voltage Source ◽  
Passive Component ◽  
Operating Range ◽  
Three Phase ◽  
Voltage Stress ◽  
Conversion Stage

Various industrial applications require a voltage conversion stage from DC to AC. Among them, commercial renewable energy systems (RES) need a voltage buck and/or boost stage for islanded/grid connected operation. Despite the excellent performance offered by conventional two-stage converter systems (dc–dc followed by dc–ac stages), the need for a single-stage conversion stage is attracting more interest for cost and size reduction reasons. Although voltage source inverters (VSIs) are voltage buck-only converters, single stage current source inverters (CSIs) can offer voltage boost features, although at the penalty of using a large DC-link inductor. Boost inverters are a good candidate with the demerit of complicated control strategies. The impedance source (Z-source) inverter is a high-performance competitor as it offers voltage buck/boost in addition to a reduced passive component size. Several pulse width modulation (PWM) techniques have been presented in the literature for three-phase Z-source inverters. Various common drawbacks are annotated, especially the non-linear behavior at low modulation indices and the famous trade-off between the operating range and the converter switches’ voltage stress. In this paper, a modified discontinuous PWM technique is proposed for a three-phase z-source inverter offering: (i) smooth voltage gain variation, (ii) a wide operating range, (iii) reduced voltage stress, and (iv) improved total harmonic distortion (THD). Simulation, in addition to experimental results at various operating conditions, validated the proposed PWM technique’s superior performance compared to the conventional PWM techniques.

scholarly journals A Simulink / MATLAB Model of a Three-Phase Sinusoidal PWM Inverter Driven Induction Motor

2019 ◽  
Vol 9 (4) ◽  
pp. 25-30
Author(s):  
Dr. Aleck W. Leedy, P.E. ◽  
◽  
Tanner Grider ◽  
Rebekah Priddy ◽  
◽  
...  
Keyword(s):  
Induction Motor ◽  
Transient Behavior ◽  
Drive System ◽  
System Model ◽  
Voltage Source ◽  
Motor Drive ◽  
Pwm Inverter ◽  
Three Phase ◽  
Student Researchers ◽  
Motor Drive System

A three-phase voltage source inverter driven induction motor dynamic model developed using Simulink / MATLAB is presented. The presented model is derived from the d-q motor model. A modular approach is used in the construction of the motor-drive system model. The model presented is useful for studying both the steady-state and transient behavior of the motor drive system. The developed model enables the user to access all parameters of interest. Modifications can be made to the system model in order for it to be used with other motor drive system topologies. The model has benefits for use by undergraduate student researchers, and professors when used as a teaching tool in undergraduate courses.

The Role of Dissolved and Nascent Air in Oil-Hydraulic Systems

2000 ◽  
Author(s):  
Hansjoerg Stern
Keyword(s):  
Steady State ◽  
High Performance ◽  
Transient Behavior ◽  
Operating Conditions ◽  
Phase System ◽  
Hydraulic Systems ◽  
Three Phase ◽  
Significant Damage ◽  
Water Hydraulic

Abstract In modern, high performance hydraulic systems the transient behavior of dissolving, dissolved and nascent air under changing dynamic conditions of pressure and temperature is emerging as an increasingly important factor, capable of creating undesirable operating conditions. The paper discusses the question of how to predict the performance of pump inlets and valve discharges, where we have known for some time that cavitation and cavitation-like conditions exist and can cause significant damage. The steady state conditions at which nascent air evolves from saturated air-in-oil solutions is normally one or two orders of magnitude above the vapor pressure of the system fluid. To what extent, therefore, is “cavitation” in these systems an air-oil problem? Or is it an oil-vapor problem that is analogous to cavitation in water hydraulic pumps and turbines? Or have we created the combination of the two, a three-phase system of liquid, gas and vapor?

scholarly journals A New PLL Simulation Validation for Three-phase Grid under Heavy Distorted Conditions

2015 ◽  
Vol 11 (7) ◽  
pp. 37
Author(s):  
Yingwen Long ◽  
Yuhong Sun
Keyword(s):  
Digital Simulation ◽  
Good Choice ◽  
Positive Sequence ◽  
Output Performance ◽  
Simulation Validation ◽  
Synchronous Reference Frame ◽  
Three Phase ◽  
Reference Frame Transformation ◽  
Frame Transformation ◽  
Grid Connected Inverter

The precision of phase-locked loop (PLL) has a direct effect on the output performance for three-phase grid-connected inverter or three-phase active PFC. In this paper, a new three-phase digital closed-loop phase-locked algorithm is proposed on the basis of synchronous reference frame transformation. Synchronous simulation of the PLL techniques is a good choice even if the polluted three-phase grid such as the harmonics, phase jump and unbalance. Finally, MATLAB digital simulation results prove that the proposed PLL can fast and accurately track the positive sequence fundamental components of three-phase grid voltage.

scholarly journals Dynamic Modeling of HVDC for Power System Stability Assessment: A Review, Issues, and Recommendations

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4829
Author(s):  
Tarek Abedin ◽  
M. Shahadat Hossain Lipu ◽  
Mahammad A. Hannan ◽  
Pin Jern Ker ◽  
Safwan A. Rahman ◽  
...  
Keyword(s):  
Steady State ◽  
Dynamic Modeling ◽  
Direct Current ◽  
Current Source ◽  
Computational Cost ◽  
Operating Conditions ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Stability Assessment

High-voltage direct current (HVDC) has received considerable attention due to several advantageous features such as minimum transmission losses, enhanced stability, and control operation. An appropriate model of HVDC is necessary to assess the operating conditions as well as to analyze the transient and steady-state stabilities integrated with the AC networks. Nevertheless, the construction of an HVDC model is challenging due to the high computational cost, which needs huge ranges of modeling experience. Therefore, advanced dynamic modeling of HVDC is necessary to improve stability with minimum power loss. This paper presents a comprehensive review of the various dynamic modeling of the HVDC transmission system. In line with this matter, an in-depth investigation of various HVDC mathematical models is carried out including average-value modeling (AVM), voltage source converter (VSC), and line-commutated converter (LCC). Moreover, numerous stability assessment models of HVDC are outlined with regard to stability improvement models, current-source system stability, HVDC link stability, and steady-state rotor angle stability. In addition, the various control schemes of LCC-HVDC systems and modular multilevel converter- multi-terminal direct current (MMC-MTDC) are highlighted. This paper also identifies the key issues, the problems of the existing HVDC models as well as providing some selective suggestions for future improvement. All the highlighted insights in this review will hopefully lead to increased efforts toward the enhancement of the modeling for the HVDC system.

Steady-State and Dynamic Behavior of a Single-Phase Self-Excited Induction Generator Using a Three-Phase Machine

2007 ◽  
Vol 8 (3) ◽  
Author(s):  
S. N. Mahato ◽  
M. P. Sharma ◽  
S. P. Singh
Keyword(s):  
Steady State ◽  
Reference Frame ◽  
Single Phase ◽  
Short Circuit ◽  
Induction Machine ◽  
Transient Behavior ◽  
Experimental Results ◽  
Induction Generator ◽  
State Variables ◽  
Three Phase

This paper presents the steady-state and transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine with one shunt and one series excitation capacitors for resistive and inductive loads. The generation scheme consists of one three-phase delta connected induction machine and two capacitors - one connected in parallel with one winding and the other in series with a single-phase load. The dynamic model of the system has been developed as a hybrid model considering the stator phase currents in abc reference frame and the rotor currents in stationary d-q axes reference frame as state variables. The simulated and experimental results are presented for different dynamic conditions such as initiation of self-excitation, load perturbation and short-circuit. The simulated results of the steady-state analysis have been compared with the transient and experimental results and a close agreement between them indicates the accuracy and effectiveness of the approach.

Modified Power Compensation Control Strategy of Three-Phase Grid-Connected Inverter under Unbalanced Grid Voltage Conditions

2015 ◽  
Vol 740 ◽  
pp. 335-338 ◽  
Author(s):  
Shao Hua Sun ◽  
Hong Qi Ben
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Positive Sequence ◽  
Grid Voltage ◽  
Compensation Control ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Grid Connected Inverter ◽  
Three Phase Inverter ◽  
Unbalanced Grid

Control strategy under unbalanced grid voltage conditions is one of the most important issues for grid-connected inverter. Under unbalanced grid voltage conditions, the 2nd active and reactive power ripples generate, they pollute the grid. To meet the demands of IEEE Std.929-2000, this paper proposed a modified power compensation control strategy; the proposed solution is based on direct power control. To provide accurate compensating power, the power model of three-phase inverter under unbalanced grid voltage conditions is given, using the positive sequence current component and the negative sequence voltage component, the compensating powers are calculated in details. Theoretical analysis and comparative simulation verification are presented to demonstrate the effectiveness of the proposed control strategy.

scholarly journals Research on SVPWM Method and its Neutral Point Potential Control

2011 ◽  
Vol 2-3 ◽  
pp. 39-42
Author(s):  
Yan Liu ◽  
Xu Wang ◽  
Yan Xing
Keyword(s):  
Passive Control ◽  
Balance Control ◽  
Neutral Point ◽  
Superior Performance ◽  
Voltage Source ◽  
Effective Control ◽  
Potential Control ◽  
Point Potential ◽  
Voltage Vector ◽  
Three Phase

Neutral-point potential unbalance is an inherent problem of Neutral-point-clamped three-level PWM rectifiers. If the problem of neutral point can’t be controlled appropriately, the harm of input current will increase, and even the dc-link capacitor and switches will be destroyed. Thus domestic and foreign experts have done lots of research on the balance control of Neutral-point-clamed and put forward many effective control methods. This paper proposes a novel SVPWM strategy for the three-level neutral-point-clamped voltage source inverter, based on the particular disposition of all the redundant voltage vectors. The new modulation approach shows superior performance for the harmonic voltage and the control of neutral-point potential compared to the popular eight-stage centered SVPWM and realizes the balancing control of inverter neutral-point potential by modifying redundant small vectors pairs’ distribution factor accurately, only requiring the information of dc-link capacitor voltages and three-phase load currents, which is convenient to apply and is compatible of digital computer realization. The feasibility of the proposed control approach has been verified via simulation and experiment results. In the strategy of software control, domestic and foreign scholars propose numerous neutral point potential control schemes. When carrier modulation is used, the balance control is achieved by injecting zero-sequence component into the three-phase modulated wave. When space vector modulation methods are adopted, they can be divided into three categories: passive control, hysteresis control and active control. there is also a new algorithm based on the intrinsic relationship between SVPWMs for two—level inverters and three．1evel inverters．a novel SVPWM control algorithm is proposed for three．1evel．The dwell time of voltage vector for three-level inverter can be acquired from counterpart for two-level inverter by using a linear transformation．Aiming to analysis the output PWM sequence of three-level inverter, a novel classification standard of voltage vector is proposed．Based on evaluating the PWM sequences, a novel PWM sequence is given，that can reduce the total harmonics distortion of inverter output.

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