Three-phase Inverter Research Articles

A novel RMPC strategy for three-phase inverters operating in grid-connected and standalone modes

One of the main features of microgrids is the capability of operating in both grid-connected (GC) and standalone (SA) modes. This paper presents a novel dual mode robust model predictive control (RMPC) strategy for a three-phase inverter with an LCL filter in both GC and SA operating modes under the filter’s parameter uncertainty. At first, a disturbance observer gain is obtained by solving a linear matrix inequality (LMI), which is determined to preserve the stability of the algorithm. The designed disturbance observer takes into account the polytopic uncertainty of system parameters. A performance index with two weighting matrices is then defined and solved in an infinite horizon by turning it into an optimization problem under LMI constraints. The performance of the control strategy highly depends on the weighting matrices. Hence, an optimization algorithm is formulated to ascertain the best matrices values for both GC and SA operation modes. Given the nonlinearity issue, particle swarm optimization (PSO) is employed to derive the optimal weighting matrices offline. To evaluate the proposed control strategy’s effectiveness, simulations and experiments are performed under several scenarios in both GC and SA operating modes. The results reveal the proposed control strategy’s powerfulness compared to other techniques in the presence of grid voltage and load current disturbances for both inverter operating modes.

Voltage regulation during short-circuit faults in low voltage distributed generation systems

As the penetration of inverter-based distributed generations into microgrids continues to rise, the significance of power electronic inverters in modern power systems becomes increasingly pronounced. They are designed to have fault ride-through capabilities, enabling them to sustain operation even during and after fault conditions. This paper presents a novel voltage compensation strategy based on the line impedances addressing both positive and negative-sequence aspects, for a three-phase three-wire inverter deployed to regulate the low-voltage network during unsymmetrical faults, thereby preserving voltage stability. The control strategy is carried out in a synchronous reference frame (dq) to govern the positive and negative-sequence voltages and currents of the inverter. By synthesizing AC currents, the inverter restores the positive-sequence voltage to its rated value while mitigating negative-sequence voltage at the point of common coupling arising from unsymmetrical faults. Through MATLAB/Simulink, are investigated three unsymmetrical fault scenarios (single line-to-ground, line-to-line, and double line-to-ground faults) within the low-voltage distribution network of the 18-bus European Cigré, incorporating three inverters equipped with the proposed voltage support capability. The results confirm that inverter-interfaced distributed generators with local voltage support can improve the system’s fault ride-through capability by reducing voltage drops and unbalances.

Design and implementation of an improved adaptive embedded-factor current controller for three-phase grid-connected inverter

This paper presents an improved current controller based on a series proportional integral resonant structure in synchronous reference frame in order to address low-order harmonics issue of the injected-grid current for three-phase grid-connected inverter. Additionally, to improve dynamic performance, an adapted factor is embedded into the proposed controller structure. Moreover, to design the parameters of the proposed controller, different constraint conditions are investigated. Based on the proposed controller structure and parameters design method, satisfactory steady-state and faster dynamic performances are both obtained in comparison to those of the conventional parallel proportional integral resonant controller. What's more, the proposed controller is easy to implement in practice. Simulation and experimental results are finally given to verify the effectiveness and superiority of the proposed controller.

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.

An energy efficient control method of a photovoltaic system using a new three-phase inverter with a reduced common mode voltage

This paper presents a new energy-efficient space vector pulse width modulation (SVPWM) for controlling the switches of a New three-phase inverter (NTPI) for photovoltaic (PV) applications to reduce switching losses, the peak value, and the dv/dt of the common mode voltage (CMV) with fewer number of switches. The proposed system offers a reliable operation in PV energy system with less leakage current and increased efficiency because of the reduction of the CMV, the source of leakage current in PV inverter-based application. Moreover, this also optimizes the operation of electric vehicle application with lower bearing failure. The performance of the proposed system with the new SVPWM is evaluated to the existing PWM in the literature, as well as the active zero state pulse width modulation (AZSPWM) of the two-level inverter introduced under identical conditions. Experiments and MATLAB simulations have both been used in this study.

Assessment of Power Quality Enhancement in a Grid-tied PV Network via ANN-based UPQC

Background: Microgrid is the recent decade terminology that surpasses the long-run issues associated with the public and utility grids. Among the renewable energy sources, solar PV units have gained greater importance owing to their huge potential availability and laidback operating characteristics on technological grounds. Conversely, it offers pollution-free electricity and perhaps the dependability is volatile in most situations. The literature study accumulates the foresaid setback and presents the fluctuation-less and controlled standard quality of power outputs. Objective: The aim of this particular research is to propose an assessment of Power Quality enhancement in a Grid-tied photovoltaic (PV) network via ANN-based UPQC. The novel idea behind this proposed approach is the UPQC component which deliberately regulates and controls the power system to achieve higher levels of power quality, ultimately meeting the recent IEEE standards. Method: This particular research enhances the performances of UPQC employed in the microgrid unit by replacing the traditional PI controller with a multi-layered feed-forward-type ANN controller for the current regulation of the series active filter. Additionally, a training algorithm for the ANN controller is built, trained and simulated via MATLAB/Simulink platform. The ANN-based UPQC is proposed to alleviate the power quality challenges like sag and swell in voltage, harmonic distortion, the time required for voltage compensation, and power factor. Therefore, UPQC is equipped to enrich the standard of power transfer at the point of common coupling inside the power frameworks, respectively. Result: Finally, the simulation results are presented to validate the operation of the grid-tied PV network via an ANN-based UPQC system. To show the enriched performance of the proposed topology, a comparative analysis is made with PI controller-based UPQC, and outcomes infer to be in agreement with the theoretical discussions. Also, the ANN-based proposed approach reduces the restoration time and THD as well under both sag and swell conditions, respectively. Conclusion: In this articulated work, a PV power system network with a DC-DC converter and three-phase inverter is employed for grid integration. The peak power extraction is ensured via a DC-DC converter with an incremental conductance algorithm. Both UPQCs are analysed and experimented via MATLAB/Simulink platform with inconstant nonlinear loads to investigate the indices mentioned above and corroborate the same within the operating regions.

A non-isolated PFC bridgeless SEPIC-Cuk converter with adaptive PI controller for induction motor

In general, the induction motor (IM) is extremely nonlinear in nature and frequency dependent. In most cases, the power generated by the IM has a low power factor (PF), which exhibits detrimental effect on the extent to which the whole transmission and distribution system functions. Since there exists more current harmonics as an outcome of minimized PF, the efficiency of the power system suffers due to transmission line heating and voltage distortion characteristics. Therefore, this paper proposes a power factor correction (PFC) method to overcome the aforementioned issues. Here, by the utilization of AC-DC bridgeless SEPIC-Cuk converter, the power quality is improved by reducing reactive power consumption and enabling better control of voltage and current outputs. To maintain the stable DC link voltage with reduced ripples, the adaptive proportional-integral (PI) controller is used in this work. The three-phase voltage source inverter (VSI) transitioning function is controlled by cascaded fuzzy logic (CFL) controller, which is also utilized for regulating the speed of the three-phase IM. Implementing the proposed control strategy improves power quality significantly by reducing total harmonic distortion (THD). The proposed system is simulated in the MATLAB platform and the attained outcomes, it is clear that the proposed system is highly effective.

Review of Three-Phase Soft Switching Inverters and Challenges for Motor Drives

Review of Three-Phase Soft Switching Inverters and Challenges for Motor Drives

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.

Enhancing of single-stage grid-connected photovoltaic system using fuzzy logic controller

The power generated by photovoltaic (PV) systems is influenced by environmental factors. This variability hampers the control and utilization of solar cells' peak output. In this study, a single-stage grid-connected PV system is designed to enhance power quality. Our approach employs fuzzy logic in the direct power control (DPC) of a three-phase voltage source inverter (VSI), enabling seamless integration of the PV connected to the grid. Additionally, a fuzzy logic-based maximum power point tracking (MPPT) controller is adopted, which outperforms traditional methods like incremental conductance (INC) in enhancing solar cell efficiency and minimizing the response time. Moreover, the inverter's real-time active and reactive power is directly managed to achieve a unity power factor (UPF). The system's performance is assessed through MATLAB/Simulink implementation, showing marked improvement over conventional methods, particularly in steady-state and varying weather conditions. For solar irradiances of 500 and 1,000 W/m<sup>2</sup>, the results show that the proposed method reduces the total harmonic distortion (THD) of the injected current to the grid by approximately 46% and 38% compared to conventional methods, respectively. Furthermore, we compare the simulation results with IEEE standards to evaluate the system's grid compatibility.

Real-Time Diagnosis of Open Circuit Faults in Three-Phase Voltage Source Inverters

Real-Time Diagnosis of Open Circuit Faults in Three-Phase Voltage Source Inverters

Light Load Efficiency Improvement for Three-Phase Inverter Employing Valley Switching Under Mixed TCM/DCM Operation

Light Load Efficiency Improvement for Three-Phase Inverter Employing Valley Switching Under Mixed TCM/DCM Operation

Design and Implementation of Model Parameter Independent Robust Current Control Scheme of Three-Phase Inverter - A Neural Network-Based Classification Approach

Design and Implementation of Model Parameter Independent Robust Current Control Scheme of Three-Phase Inverter - A Neural Network-Based Classification Approach

Modeling and simulation of three-phase IGBT full-bridge inverter circuit based on FPGA

The field of motor drive makes extensive use of electronic power modeling and simulation of three-phase IGBT full-bridge inverter circuits. The accuracy and computational efficiency of these models have a direct impact on the dependability of the motor control system. The majority of earlier research focused solely on static processes of turning on and off in IGBTs, disregarding the transient proesses that occur when three-phase IGBT full-bridge inverter circuits are switched at high frequencies. This has an impact on the circuits' accuracy in real-time simulation. Therefore, this paper proposes and builds a field-programmable logic gate array (FPGA)-based steady-state and transient dual-phase three-phase IGBT full-bridge inverter circuit model for the static and transient characteristics of the insulated gate bipolar transistor (IGBT) element in the circuit. Depending on whether or not the switching states of the six IGBTs in the three-phase IGBT full-bridge inverter circuit are altered, the simulation process is split into steady state and transient phases. In the steady state phase with large step size, the circuit is discretized using the binary L/C approach. In the transient phase, the transient process is divided into several small-step-long time domains. Real-time simulation waveforms are generated by interleaving and combining the multistage fitting method's solution of the circuit's transient waveforms at tiny step lengths with the steady state phase. Finally, in order to demonstrate the accuracy of the circuit model in this work, the simulation results of the two-stage three-phase IGBT full-bridge inverter circuit model based on FPGA are compared with those of the conventional ideal model for waveform comparison and data analysis.

Comparison of three-phase inverter modulation techniques: a comprehensive analysis of SPWM and SVPWM

With the increasing utilization of renewable energy sources like solar and wind, three-phase inverters have become indispensable equipment for grid-connected energy systems, sparking significant research interest in the field of power electronics. This paper presents a comprehensive comparison of two primary modulation techniques employed in three-phase inverters: Sinusoidal Pulse Width Modulation (SPWM) control and Space Vector Pulse Width Modulation (SVPWM) control. The aim is to elucidate their respective advantages and disadvantages, particularly focusing on their performance under various control models. Through a systematic analysis of parameters such as total harmonic distortion under different control schemes including the unity power factor control model, the V/F control model, and the modulation ratio, this paper delves into the operational principles, strengths, and weaknesses of SPWM and SVPWM. Additionally, it elucidates the distinctions between these two modulation techniques and their interconnections. Lastly, the paper provides insights into the future development prospects and identifies potential technical challenges in the realm of pulse width modulation techniques.

Advanced detection and localization of open circuit faults in two-level three-phase IGBT-based inverters using machine learning approaches and discrete wavelet transform

Advanced detection and localization of open circuit faults in two-level three-phase IGBT-based inverters using machine learning approaches and discrete wavelet transform

Power Regulation of a Three-Phase L-Filtered Grid-Connected Inverter Considering Uncertain Grid Impedance Using Robust Control

Uncertain grid impedance is often common in power distribution networks; therefore, it is crucial to design an efficient controller in this situation. An issue that frequently occurs is the problem of unpredictable grid impedance, which can cause voltage fluctuations, power quality problems, and potential damage to equipment. This work provides a systematic control strategy to tackle these issues by supplying well-regulated power from a DC source to an AC power grid. A linear matrix inequality (LMI)-based robust optimal control is proposed in this paper to provide stability to the inverter system without offset error at the output side. The convergence time to steady state is minimized by solving the LMI problem to maximize the eigen value of the closed-loop system with the inclusion of the uncertainty of the filter parameter and grid impedance. Furthermore, the uncertainties in this study include the potential variation of values for the filters and the grid's impedance. These uncertainties occur because the grid impedance can fluctuate fast in the event of a fault or termination of a transmission line, while the filter's impedance can also be affected by changes in operating temperature. The simulation study of this proposed control includes a comparison between wide and narrow uncertainty ranges, as well as a performance comparison under uncertain parameters. Furthermore, this approach exhibits a lower power ripple in comparison to existing PI control method.

Single Three-Phase Inverter for Dual-Frequency Induction Heating

This paper presents new resonant inverter topologies for dual-frequency induction heating (IH). These 2T1C and 3T topologies combine the advantageous features of two- and one-inverter solutions. An analytical description of the load impedance of a dual-frequency series-parallel circuit has been made. Using manufacturer datasheets and LTspice models of selected transistors, a MATLAB model was parameterized. Based on it, power losses are determined as a function of the following parameters: nominal power, frequency and DC bus voltage. The obtained results allowed for determining the data necessary in the design process. The research has been experimentally verified. Tests were carried out for pulsing and simultaneous operation. Power control characteristics as a function of frequency are determined. The possibility of operating the inverter with high efficiency (>97%) in the proposed 2T1C and 3T systems at nominal power is demonstrated.

Efficiency Analysis of Hybrid Extreme Regenerative with Supercapacitor Battery and Harvesting Vibration Absorber System for Electric Vehicles Driven by Permanent Magnet Synchronous Motor 30 kW

This research presents an approach to the hybrid energy harvesting paradigm (HEHP) based on suspended energy harvest. It uses a harvesting vibration absorber (HVA) with an SC/NMC-lithium battery hybrid energy storage paradigm (SCB-HESP) equipped regenerative braking system (SCB-HESP-RBS) for electric vehicles 2 tons in gross weight (MEVs) driven by a 30 kW permanent magnet synchronous motor (PMSM). During regenerative braking, the ANN mechanism controls the RBS to adjust the switching waveform of the three-phase power inverter, and the braking energy transfers to the energy storage device. Additionally, a supercapacitor (SC) equipped with HVA can absorb energy from vehicle vibrations and convert it into electrical energy. The energy-harvesting efficiency of MEV based on SCB-HESP-RBS using HVA suspended energy harvesting enhances the efficiency maximum to 50.58% and 15.36% in comparison to MEV with only-HVA and SCB-HESP-RBS, respectively. Further, the MEV with SCB-HESP-RBS using HVA has a driving distance of up to 247.34 km (22.5 cycles) when compared with SCB-HESP-RBS (214.40 km, 19.5 cycles) and only-HVA (164.25 km, 15 cycles).

Optimized and Sustainable PV Water Pumping System with Three-Port Converter, a Case Study: The Al-Kharijah Oasis

Optimized and Sustainable PV Water Pumping System with Three-Port Converter, a Case Study: The Al-Kharijah Oasis