Voltage Source Inverter Research Articles

Disturbance Observer-Based Feedback Linearized Controller for Grid-Forming Four-Leg VSI Supplying Unbalanced and Nonlinear Loads

This paper presents the design of a disturbance observer-based controller that regulates the output voltage of three-phase four-leg voltage source inverters (VSIs) deployed for grid-forming operation in Renewable Energy-based Distributed Generation (REDG) Systems. The primary objective of the controller is to provide a symmetric and sinusoidal voltage at the output of the VSI when supplying highly unbalanced and nonlinear loads. The controller employs the feedback linearization (FL) technique and incorporates a disturbance observer (DO) to address a range of disturbances that include oscillations resulting from unbalanced loads, harmonics generated by nonlinear loads, and non-oscillatory disturbances. Notably, the controller adopts a direct control scheme without the need for nested current control loops and does not use any transformation frames. Simulation studies and experimental investigations were conducted to assess the controller’s performance under various load conditions, including both linear and nonlinear types, as well as load transients. The findings demonstrate the controller’s capability to accurately track references while complying with the IEEE power quality standards for the tested conditions.

A hybrid methodology based battery power management and torque control of open-end winding induction motor drive for electric vehicles

This paper proposes a hybrid strategy for an isolated battery-powered induction motor drive with two stages fed by an inverter and open-end winding, designed for electric vehicle applications. The hybrid approach, termed EOO-RERNN, combines the Eurasian Oystercatcher Optimizer (EOO) and Recalling Enhanced Neural Network methods. RERNN predicts the control pulses generated by EOO, which are utilized to control the voltage source inverter (VSI) switches. The system comprises dual motors, two battery packs (BPs), and VSIs supplying power to both the rear motor (RM) and front motor (FM). The primary objective of the EOO-RERNN technique is to regulate each DC-link's power share to maintain equilibrium in the electric vehicle's charge. Direct Torque Control (DTC) is employed due to its quick and precise torque response and tolerance for parameter variations. Proper tuning is required to control the state of charge battery level. The EOO-RERNN method is implemented in the Matrix Laboratory (MATLAB) platform, with performance contrasted to other methods such as Wild Horse Optimizer (WHO), Grasshopper Optimization Algorithm (GOA), and Heap-Based Optimizer (HBO). Simulation results indicate a motor speed of 4850 rpm for the EOO-RERNN method.

Stabilized voltage source inverter for sensitive loads in nuclear installations

The present paper proposes a novel design of a stabilized single-phase voltage-source inverter with pure sinusoidal output voltage for photovoltaic systems employed for feeding sensitive loads in nuclear installations. Such types of loads require a voltage source with quite stabilized magnitude and frequency and pure sinusoidal shape that is free from higher-order harmonics. The inverter is based on an H-bridge four insulated gate bipolar transistors (IGBTs) with gate drivers and optocoupler isolators. A control system based on a fast DSP unit and a microcontroller is designed for cancelation of the higher-order harmonics to produce a pure sinusoidal output with almost zero total harmonic distortion (THD). The sinusoidal purity, frequency and magnitude stabilization are achieved through pulse width modulation (PWM) controlled by a fast-response feedback system that measures the time wave form of the output voltage applied to the load and then calculates the THD, frequency and amplitude. The sinusoidal shaping is performed with aid of a sinusoidal shaping filter (SSF) to fasten the operation of higher-order harmonic cancellation. The frequency measurement is achieved through a frequency counter whereas the amplitude measurement is carried out through a differential amplifier that amplifies the difference between the output voltage of the inverter (while being applied to the load) and reference voltage that determines the desired amplitude. A prototype of the entire system of the proposed voltage-source inverter is fabricated for experimental evaluation of its performance. It is shown through simulation and experimental work that the proposed control system of the inverter output voltage is able to stabilize both the amplitude and frequency of the voltage applied to the load irrespective of the load impedance. Also, it is shown that the THD of the output voltage is -57dB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-57 \ ext{ dB}$$\\end{document} (0.00025%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.00025 \\%$$\\end{document}), which is almost zero. Moreover, the switching losses are considerably reduced and can be negligible owing to the use of the appropriate IGBTs. The efficiency of the proposed inverter is obtained by simulation taking into account all types of losses. Also, the dependence of the inverter efficiency on the load current is investigated. The average efficiency of the proposed voltage-source inverter is shown to be higher than 97%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$97\\%$$\\end{document}.

MEDIUM-POWER DRIVE INSTALLATIONS BASED ON TRIPLE VOLTAGE SOURCE INVERTERS ADJUSTED BY ALGORITHMS OF SYNCHRONOUS MULTI-ZONE PWM

This paper presents short overview of the development and dissemination of specialized schemes and algorithms of space-vector-based synchronous multi-zone pulsewidth modulation (MZ PWM) for control of triple inverters of the medium-power variable speed drives characterized by relatively low switching frequency of inverters. It insures providing synchronization and symmetry of the basic voltage waveforms in triple-inverter-based configurations of drive installations on the base of standard voltage source inverters (VSIs). It assures also minimization of magnitudes of even-order harmonics and undesirable subharmonics in spectra of the basic voltages of drive installations, leading to reducing of losses in the corresponding apparatuses and to increasing of its efficiency. Examples of application of the basic techniques of multi-zone PWM for regulation of three typical structures of triple-VSI-based medium-power motor drives are presented. Modeling and simulations give a behavior of drive installations based on triple inverters adjusted by algorithms of synchronous MZ PWM. References 12, figures 11, table 1.

Direct Power Regulation of Grid-Connected Voltage-Source Inverters Based on Bang-Bang Funnel Control

Direct Power Regulation of Grid-Connected Voltage-Source Inverters Based on Bang-Bang Funnel Control

Squirrel Cage Induction Motor (SCIM) Rotor Flux Estimation and Observer Using Multivariable Sliding Mode Control (MSMC)

This paper proposes a multivariable sliding mode control (MSMC) based in rotor flux estimation and observer methods for squirrel cage induction motor (SCIM). The principle of sliding mode control (SMC) adjustment can also be applied to multivariable systems. In this case, for each control quantity, there is a control member who switches the latter quickly between a maximum value and a minimum value, thus causing the sliding mode to appear. This article will discuss sliding mode tuning of multivariable systems, highlighting issues that arise in relation to mono-variable systems studied so far. In this paper, we will establish the general relationships, where we introduce the regulators of multivariable systems. To describe the behavior in sliding mode, we will call or equivalent control vector, at the end of this article we will introduce a rotor flux observer to improve the results obtained. The work is developed with a 2-level voltage source inverter. The simulation results are carried out to verify and validate the multivariable sliding mode control method proposed based rotor flux estimation and observer scheme

Predictive Controller Strategies for Electrical Drives System using Inverter System

Advanced control strategies in power electronics include Predictive controller of current (P CURRENT CONTROL) and Predictive controller of torque (P TORQUE CONTROL). In order to operate a SRM or an induction machine, the Predictive controller of torque (P TORQUE CONTROL) approach analyses the stator flux and electromagnetic torque in the cost function (IM), and the Predictive controller of current (P CURRENT CONTROL) method [1,2] takes errors between the current reference and the measured current into account in the cost function. The switching vector selected for usage in IGBTs reduces the error between the references and the predicted values. The system restrictions are easy to include [4, 5]. The weighting component is not required. Together with the P TORQUE CONTROL and P CURRENT CONTROL systems, the SRM method is the most practicable direct control technique since it doesn't require a modulator and offers 10% to 30% more power than an induction motor [3]. With the same current, an induction motor can only generate between 70 and 90 percent of the force generated by an SRM due to its lagging power factor. SRM approach decreases 23% more THD in torque, speed, and stator current when P CURRENT CONTROL and P TORQUE CONTROL method with 15-level H-bridge multilevel inverter is compared to P CURRENT CONTROL and P TORQUE CONTROL method with 15-level H-bridge multilevel inverter utilising induction motor [21]. The transistors are only swapped when necessary to maintain the limits of torque and flux, which minimises switching losses. To improve the efficiency of a multilevel inverter, semiconductor switches are switched in a specific pattern. In contrast to the P TORQUE CONTROL and P CURRENT CONTROL approaches using a 2-level voltage source inverter, the 15-level H-bridge multilevel inverter employed in this study, coupled with SRM and IM, gives outstanding torque and flux responses and achieves robust and stable operation. This unique strategy quickly caught the interest of academics due to its simple algorithm and high performances in both steady and transient modes [8].

An Experimental Investigation on VSI-fed Induction Motor using Xilinx ZYNQ-7000 SoC Controller

In medium voltage and high-power drive applications, pulse width modulation (PWM) techniques are widely used to achieve effective speed control of AC motors. In real-time, an industrial drive system requires reduced hardware complexity and low computation time. The reliability of the AC drive can be improved with the FPGA (field programmable gate array) hardware equipped with digital controllers. To improve the performance of AC drives, a new FPGA-based Wavect real-time prototype controller (Xilinx ZYNQ-7000 SoC) is used to verify the effectiveness of the controller. These advanced controllers are capable of reducing computation time and enhancing the drive performance in real-time applications. The comparative performance analysis is carried out for the most commonly used voltage source inverter (VSI)-based PWM techniques such as sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) for three-phase, two-level inverters. The comparative study shows the SVPWM technique utilizes DC bus voltage more effectively and produces less harmonic distortion in terms of higher output voltage, flexible control of output frequency, and reduced harmonic distortion at output voltage for motor control applications. The simulation and hardware results are verified and validated by using MATLAB/Simulink software and FPGA-based Wavect real-time controller respectively.

High gain interleaved PFC converter for torque ripple minimization in industrial PMBLDC motor based drives

The necessity of motors is proliferating in almost all the modern era applications as the motors play a significant role in lessening the manual labour and minimizing the consumption of time. As the consequence of having many meriting measures like minimal expenditure, substantial efficacy, massive robustness, and uncomplicated structure, the Permanent Magnet Brushless DC (PMBLDC) motor is preferred in this present study. For the target of achieving ripple-free operation, a Bridgeless High-Resolution Pulse Width Modulation (HR PWM) converter is instigated as a replacement of traditional Diode Bridge Rectifier (DBR) in this paper, which assists in procuring the aim of Power Factor Correction (PFC). The regulation of converter output is obtained with the assistance of the Adaptive Cascaded Fuzzy Controller, which optimizes and retains the output as constant. The optimized output is then fed to the motor through a Voltage Source Inverter (VSI). Eventually, the Grey Wolf Optimization (GWO) tuned PI controller is magnificently implemented to manage motor speed regulation without any interruptions or uncertainties. Hence, the introduced approach performs well in ripple suppression, PFC, and torque regulation processes. The utilized converter provides improvised results with the efficiency of 97 %, The entire work is validated through MATLAB simulation and FPGA Spartan 6E in hardware.

Model-free predictive flux vector control for N ∗ 3-Phase PMSM drives considering parameters mismatch

This paper develops a novel model free-predictive flux vector control method (MF-PFVC) for high-performance stator flux and torque monitoring of the multi-module three-phase PMSM (N ∗ 3-Phase PMSM) drive with parameters mismatch. The proposed MF-PFVC method is based on a convenient combination of direct predictive torque control (PTC) and model free predictive control techniques. First, the voltage source inverter (VSI) vector control of N ∗ 3-Phase PMSM is determined by the three-segment stator windings structure. Then, the parameter mismatch sensitivity of the N ∗ 3-Phase PMSM drive system is analyzed based on the conventional PTC. Furthermore, a novel MF-PFVC method with multivariable unknown disturbance integral terminal sliding mode observer (SMO) is proposed for N ∗ 3-Phase PMSM drive, which can effectively enhance robustness against the parameters mismatch. Finally, compared with the conventional PTC, the simulation and experimental results of MF-PFVC method illustrated improved stator flux control performance concerning lower stator flux ripple as well as reduced torque ripple while it can eliminate the influence of parameter mismatch.

Artificial Intelligence with Metaheuristic Algorithm Based Optimization for a Hybrid Energy Storage System

This paper presents an optimization framework for a hybrid energy storage system (HESS) integrating photovoltaic (PV) and wind energy conversion systems (WECS). The PV system voltage is stepped up using a Cuk converter, controlled by a Particle Swarm Optimization (PSO) tuned Artificial Neural Network (ANN) controller to enhance dynamic performance and ensure maximum power point tracking (MPPT). The Doubly Fed Induction Generator (DFIG) based WECS is interfaced through a Pulse Width Modulation (PWM) rectifier regulated by a Proportional Integral (PI) controller, maintaining stable and efficient power conversion. Both converter outputs converge at a common DC link, whose voltage is subsequently applied to a single phase Voltage Source Inverter (VSI). This VSI is connected to the grid through an LC filter, ensuring smooth power delivery with minimal harmonics. The proposed system combines AI and metaheuristic algorithms for optimized control, enhancing overall efficiency, reliability and stability of the renewable energy integration into the grid. Simulation results demonstrate the effectiveness of the PSO ANN and PI control strategies in managing the dynamic interactions and power quality of the hybrid system. The proposed hybrid controller shows 92.47% tracking efficiency and the proposed converter shows 89.6% efficiency.

PV Connected Grid System Using Modified Boost Converter with AI Based Controller

Grid connected solar Photovoltaic (PV) system has a fast growing rate and rapidly becoming an essential part in power distribution systems. Solar energy generated through PV array completely depends on atmospheric conditions, changes in weather affects the amount of output energy, and hence the system needs to be improved according to changes in climate. Thereby, this work focuses on Modified Boost Converter (MBC) with AI based controller for optimizing the performance of grid connected PV module. Moreover, Artificial Neural Network (ANN) based Maximum Power Point Tracking (MPPT) is used in extracting maximum output power from PV system. The single phase Voltage Source Inverter (1 VSI) is utilized in converting the DC supply into AC. For verifying the performance of grid connected PV, it is implemented in MATLAB. The results demonstrates that the proposed converter results with higher voltage gain compared to the other conventional converters.

Comparative Analysis of Single Stage and Dual Stage PV Based Generation System for Pollution Reduction in Asian Nations

The growing need for sustainable and clean energy solutions has elevated photovoltaic (PV) systems to the forefront of competitive options. In order to evaluate the performance and viability of single-stage and dual-stage single-phase PV voltage source inverter systems within the context of renewable energy, this study undertakes a thorough comparative analysis. MATLAB Simulink has been used to run the simulations, and the results produced show that the selected configurations are robust and closely match theoretical expectations. The study explores the subtle distinctions, benefits, and drawbacks that come with single- and dual-stage systems. By extensively evaluating the consequences on system stability, grid synchronisation, and power quality, useful insights emerge. The simplicity and efficiency of the single-stage system are demonstrated by the direct connectivity between the PV MPPT output and the inverter. In contrast, the dual-stage system addresses the issue of low PV output voltage by incorporating a boost converter with an MPPT algorithm, albeit at the expense of more parts and complexity. The research described here adds a great deal to the current discussion on PV system optimization. The study notably clarifies methods for improving dependability and efficiency in applications involving renewable energy. With the increasing worldwide trend towards sustainable energy, it is critical to comprehend the subtle dynamics of various PV setups. In addition to offering a comprehensive grasp of the complexities involved in single- and dual-stage single-phase PV voltage source inverter systems, this research paves the way for future developments in the planning and execution of effective renewable energy solutions especially for Asian nations that still rely on coal-based power plants. Increased contribution of solar based electricity generation will lead to a significant drop in pollution contributed by the ash and gases released by thermal power plants that employ fossil fuels. The ultimate goal of this study is to provide information to stakeholders in the renewable energy industry so that they may make more informed decisions and create PV systems that are both sustainable for the environment and efficient for the utility.

Optimal weighting factor design based on entropy technique in finite control set model predictive torque control for electric drive applications

In the conventional finite control set model predictive torque control, the cost function consists of different control objectives with varying units of measurements. Due to presence of diverse variables in cost function, weighting factors are used to set the relative importance of these objectives. However, selection of these weighting factors in predictive control of electric drives and power converters still remains an open research challenge. Improper selection of weighting factors can lead to deterioration of the controller performance. This work proposes a novel weighting factor tuning method based on the Multi-Criteria-Decision-Making (MCDM) technique called the Entropy method. This technique has several advantages for multi-objective problem optimization. It provides a quantitive approach and incorporates uncertainties and adaptability to assess the relative importance of different criteria or objectives. This technique performs the online tuning of the weighting factor by forming a data set of the control objectives, i.e., electromagnetic torque and stator flux magnitude. After obtaining the error set of control variables, the objective matrix is normalized, and the entropy technique is applied to design the corresponding weights. An experimental setup based on the dSpace dS1104 controller is used to validate the effectiveness of the proposed method for a two-level, three-phase voltage source inverter (2L-3P) fed induction motor drive. The dynamic response of the proposed technique is compared with the previously proposed MCDM-based weighting factor tuning technique and conventional MPTC. The results reveal that the proposed method provides an improved dynamic response of the drive under changing operating conditions with a reduction of 28% in computational burden and 38% in total harmonic distortion, respectively.

Analysis of capacitive discharges in motor bearings under different operation conditions

AbstractDespite being a well‐known problem, bearing faults are still one of the major challenges that the industry face. The growing use of voltage source inverters imposed the alertness of possible bearing damage due to their high‐frequency signals. The aim of this paper is to investigate the effect of capacitive discharges on a rolling element bearing to obtain a series of faulty bearings with different deterioration levels. An ageing test bench is built to generate bearing roughness using Electric Discharge Machining. The purpose is to study the effect of operation conditions, such as frequency of drive, amplitude of shaft voltage, radial load level as well as rotational speed, on the capacitive discharge occurrence within the bearing. Having the desire to further understand this phenomenon, the influence of each parameter on the discharge activity and the discharge waveform is analysed. A worst‐case scenario is conducted and applied to a series of bearings. Finally, the bearing damage is examined, and a quantitative fault detection method is presented based on a microscopic inspection of the bearing's surface.

Double-Vector Model-Free Predictive Current Control Method for Voltage Source Inverters With Sampling Noise Suppression

Model-free predictive current control (MFPCC) methods based on look-up tables (LUTs) have been widely applied in voltage source inverters (VSIs) due to their simple implementation and excellent robustness. However, the performance of the VSIs is affected by the voltage vector used, accuracy of current gradients and sampling noise. In order to improve these, a new double-vector MFPCC method is proposed in this paper. First, a synthetic voltage vector composed of double vectors is applied in each control period to reduce current ripples, where the durations of the double vectors are calculated using predicted current gradients. Next, an extended LUT is designed by using the current gradients of the applied synthetic voltage vectors to update all current gradients of eight basic voltage vectors, so as to increase the accuracy of current gradients. Then, the effect of the sampling noise on MFPCC is analyzed in detail and suppressed by a sliding-mode observer (SMO) for the VSIs. Finally, simulation and experimental results have verified the effectiveness of the proposed method.

Performance evaluation of solar-PV integrated hybrid fuzzy-logic controlled multi-functional UPQC for enhancing PQ features

To improve distribution system voltage and current quality, a newly built solar-PV system connected multi-functional universal power quality compensator (MFUPQC) has been extensively used. The proposed MFUPQC mitigates both load and source-side concerns in a three-phase distribution system. Furthermore, as part of the distributed generation scheme, active power from solar PV is injected into the grid or source when solar PV is available. In this context, the proposed MFUPQC was tested in both PQ enhancement and DG integration modes using a feasible control scheme. The proportional-integral controller is used for shunt- voltage-source inverter (VSI) DC-link control, which is not suitable for regulating DC-link voltage at the desired level due to incorrect gain value selection. In this work, an intelligent hybrid-fuzzy-logic DC-link control of MFUPQC evidences the intelligent knowledge base for better regulation of power-quality issues. The suggested hybrid fuzzy-logic controlled MFUPQC device's performance for both power quality (PQ) improvement and DG integration is validated using the MATLAB/Simulink software tool, and simulation results are provided with an appealing comparison analysis.

Power quality conditioning using two-level buck inverter based DSTATCOM

A two-level buck inverter is derived from the voltage source inverter, by replacing the additional power devices and suitable combination of inductor circuits respectively. Novel isolated buck inverter, featuring each-phase conversion and soft-switching within wide operation range, is developed. An optimized control strategy is employed to realize isolated buck conversion. By utilizing the buck inverter, the voltage stress on the power devices and passive components, the self-supported capacitor and filter inductance, is reduced to the half of the output voltage. Moreover, it is proven that the thyristor-controlled series capacitor (TCSC) equipped with a well-designed distributed static compensator (DSTATCOM) can effectively improve source current harmonics reduction, power factor correction in the source side, load compensation, regulation of load voltage and upholding constant voltage across the DC-link capacitor. In order to verify the effectiveness of the proposed DSTATCOM, its performance is compared with the two level DSTATCOM. The extensive simulations are carried out using MATLAB/Simulink to analyze the results. Experimental results using dSPACE-1104 prototype verify the appropriate DSTATCOM.

Improve the voltage profile of the grid-integrated induction motor with a fuzzy-based voltage source converter

This article suggests installing a series compensator on grid-connected induction motors that allows for the ride-through of unbalanced voltage sag. Fuzzy logic controls the motor voltages in a standard three-phase voltage source inverter or voltage source inverter (VSI). An open-ended three-phase machine and the grid form a series connection for the VSI. The proposed system is well suited for uses where frequency variation is unnecessary, such as with large pumps or fans. There is no requirement for a direct current (DC) source or injection transformer when conducting an electric mutual coupling The severity of the sag in the grid voltage that will prevent EMC from shutting down is proportional to the load on the motors. An increase in the voltage of the DC link may be necessary if the voltage is not balanced. A 1.5 hp four-pole induction motor was used alongside grid voltage disturbances to test the proposed compensator's ride-through capability. Grid's current analysis demonstrates that the proposed system does not require the addition of a passive filter to achieve low levels of total harmonic distortion (THD). Additionally, the control strategy, component ratings, and analysis of the converter's output voltage operating principle and pulse width modulation technique are covered. The system's viability is shown via simulation and experimental results.

Analysis, design, and control of standalone PV based boost DC-AC converter

This paper presents a new control scheme for a boost DC–AC converter which is used for solar power applications. The proposed DC-AC converter configuration can produce an AC voltage level across the output or load side greater than input DC voltage based on the operating duty cycle. Generally, the conventional DC-AC converter or voltage source inverter (VSI) generates AC voltage which is less than input DC voltage. Maintaining a constant voltage across the load with improved dynamic performance is challenging for anyone for the solar photovoltaic (PV) system. A dual-loop sliding mode control is proposed for the boost VSI to address the above issues. The proposed controller has robust in nature against the wide fluctuation in the plant or load parameters. The design, analysis and control of the boost DC-AC converter are briefly discussed in this paper. This topology can be broadly used in solar powered uninterruptible power supply (UPS) where boosting operation is essential for low voltage solar PV system. This topology eliminates the DC boosting power processing stage which leads an improved efficiency of the overall system. The MATLAB/Simulink results are presented to highlight the above issues.