31 results
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2. Leakage Current Mitigation in Photovoltaic String Inverter Using Predictive Control With Fixed Average Switching Frequency.
- Author
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Rojas, Christian A., Aguirre, Matias, Kouro, Samir, Geyer, Tobias, and Gutierrez, Eduardo
- Subjects
- *
PHOTOVOLTAIC power systems , *STRAY currents , *ELECTRIC inverters , *PREDICTIVE control systems , *VOLTAGE control - Abstract
This paper proposes and validates model predictive control as an alternative control strategy for H-bridgeneutral-point-clamped (H-NPC) converters for single-phase grid-tied string photovoltaic (PV) systems. The presented control scheme achieves good quality current waveforms with unity power factor, dc-link voltage control, and neutral-point voltage minimization. Furthermore, the predictive controller has been further enhanced by including an average device switching frequency restriction and a $dv/dt$ mitigation. The main contribution of this paper is the avoidance of the potential leakage current due to parasitic capacitance of the PV modules by using a predictive model based control technique instead of modulated schemes and eliminating high-frequency common-mode voltage components. Experimental results during steady state and dynamic operation are presented to illustrate the behavior of the H-NPC converter commanded by the proposed control scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
3. An Effective Sliding Mode Control Design for a Grid-Connected PUC7 Multilevel Inverter.
- Author
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Makhamreh, Hamza, Trabelsi, Mohamed, Kukrer, Osman, and Abu-Rub, Haitham
- Subjects
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SLIDING mode control , *ELECTRIC inverters , *COST functions , *PULSE width modulation transformers , *ONLINE algorithms , *SAMPLING errors - Abstract
This paper proposes an effective sliding mode controller (SMC) for a grid-connected 7-level packed U-cell (PUC7) inverter. The aim is to design a simple controller that deals effectively with the complex control problem of the PUC7 inverter (multiobjective control problem). The selection of the control actions is achieved according to the system state error at every sampling time, regardless of the previous values, which makes the control technique model-independent. The control algorithm evaluates online two cost functions (one for each state error), which are derived on the basis of sliding mode theory, and it selects the optimal control input in order to satisfy the reaching conditions of the two cost functions. Compared with the existing solutions, the proposed SMC technique ensures lower average switching frequency by tuning the hysteresis bandwidth of the capacitor-voltage error. The fast implementation, needless of gains tuning, and simple design procedure are the main features of the proposed algorithm. Simulation and experimental results are presented to prove the effectiveness of the proposed technique in controlling the PUC7 inverter with high dynamic performance and robustness against disturbances and parameters mismatch. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Simultaneous Common-Mode Voltage Reduction and Neutral-Point Voltage Balance Scheme for the Quasi-Z-Source Three-Level T-Type Inverter.
- Author
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Qin, Changwei, Zhang, Chenghui, Xing, Xiangyang, Li, Xiaoyan, Chen, Alian, and Zhang, Guangxian
- Subjects
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ELECTRIC potential , *PLANT shoots , *VOLTAGE control - Abstract
The conventional three-level inverter only has voltage buck capability. The quasi-Z-source three-level T-type inverter (QZS 3LT $^2$ I) has been proposed to realize voltage buck–boost operation. In this paper, we further propose a novel modulation scheme for the QZS 3LT $^2$ I to realize voltage boosting, reduce the common-mode voltage (CMV), and control the neutral-point voltage balance simultaneously. The proposed scheme adopts a large vector, a medium vector, a small vector with low CMV magnitude, a zero vector, and a shoot-through vector to generate the output voltage. According to sector number and neutral-point voltage difference, a p-type or n-type small vector with low CMV magnitude is properly selected to balance the neutral-point voltage. Shoot-through states are inserted within zero vector to boost the dc input voltage without affecting the ac output voltage. Dwell times of basic vectors are calculated through the revised volt–second balance equation. Furthermore, a coordinate control strategy between neutral-point voltage balance and voltage boosting is proposed. Doing so, the CMV magnitude can be restricted within one-sixth of dc-link voltage and neutral-point voltage imbalance can be effectively mitigated. The effectiveness of the proposed scheme is verified by simulations and experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
5. Extended Linear Modulation Operation of a Common-Mode-Voltage-Eliminated Cascaded Multilevel Inverter With a Single DC Supply.
- Author
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S, Arun Rahul, Pramanick, Sumit, Boby, Mathews, Gopakumar, K., and Franquelo, Leopoldo G.
- Subjects
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ELECTRONIC modulation , *CAPACITORS , *INDUCTION motors , *MOTOR drives (Electric motors) , *HARMONIC distortion (Physics) , *ELECTRIC inverters - Abstract
Zero-common-mode-voltage (CMV) operation of multilevel inverters results in reduced dc-bus utilization and reduced linear modulation range. In this paper, a method to increase the linear modulation range for zero-CMV operation without increasing the dc-bus voltage using a cascaded multilevel inverter with a single dc supply is presented. Using this method, the peak fundamental output voltage can be increased from 0.499 to 0.637 \textV\text{dc} with zero CMV inside the linear modulation range. Also, various pulse width modulation (PWM) switching sequences are analyzed in this paper, and the PWM sequence that gives minimum current ripple is used for the zero-CMV operation of the inverter. The inverter topology with single dc supply is realized by cascading a two-level inverter with two floating-capacitor-fed full-bridge modules. Simulation and experimental results for steady-state and dynamic operating conditions are presented to validate the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
6. Model Predictive Control for a Dual-Active Bridge Inverter With a Floating Bridge.
- Author
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Chowdhury, Shajjad, Wheeler, Patrick W., Gerada, Chris, and Patel, Chintan
- Subjects
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PREDICTIVE control systems , *ELECTRIC inverters , *ELECTRIC transformers , *DIRECT currents , *ELECTRIC potential - Abstract
This paper presents a model predictive control technique applied to a dual-active bridge inverter where one of the bridges is floating. The proposed floating bridge topology eliminates the need for isolation transformer in a dual inverter system and therefore reduces the size, weight, and losses in the system. To achieve multilevel output voltage waveforms, the floating inverter dc-link capacitor is charged to the half of the main dc-link voltage. A finite-set model predictive control technique is used to control the load current of the converter as well as the floating capacitor voltage. Model predictive control does not require any switching sequence design or complex switching time calculations as used for space vector modulation; thus, the technique has some advantages in this application. A detailed analysis of the converter as well as the predictive control strategy is given in this paper. Simulation and experimental results to validate the approach are also presented. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
7. A Multilevel Converter With a Floating Bridge for Open-End Winding Motor Drive Applications.
- Author
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Chowdhury, Shajjad, Wheeler, Patrick W., Patel, Chintan, and Gerada, Chris
- Subjects
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CONVERTERS (Electronics) , *MOTOR drives (Electric motors) , *INDUCTION motor efficiency , *ELECTRIC inverters , *CAPACITORS - Abstract
This paper presents a three-phase open-end winding induction motor drive. The drive consists of a three-phase induction machine with open stator phase windings and dual-bridge inverter supplied from a single dc voltage source. To achieve multilevel output voltage waveforms, a floating capacitor bank is used for the second of the dual bridges. The capacitor voltage is regulated using redundant switching states at half of the main dc-link voltage. This particular voltage ratio (2:1) is used to create a multilevel output voltage waveform with three levels. A modified modulation scheme is used to improve the waveform quality of this dual inverter. This paper also compares the losses in the dual-inverter system in contrast with a single-sided three-level neutral point clamped converter. Finally, detailed simulation and experimental results are presented for the motor drive operating as an open-loop v /f controlled motor drive and as a closed-loop field-oriented motor controller. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
8. Experimental Design of Fixed Switching Frequency Model Predictive Control for Sensorless Five-Level Packed U-Cell Inverter.
- Author
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Sebaaly, Fadia, Vahedi, Hani, Kanaan, Hadi Y., and Al-Haddad, Kamal
- Subjects
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PREDICTIVE control systems , *SWITCHING circuits , *FREQUENCY changers , *ELECTRIC inverters , *VOLTAGE control , *MATHEMATICAL optimization - Abstract
In this paper, a fixed switching frequency model predictive current controller is designed and implemented on a sensorless five-level packed U-cell (PUC5) inverter interfacing the utility. The predictive control methodology is based on a voltage vector generation technique for the cost function optimization by nullifying its derivative. The aim of the controller is to allow a fixed-frequency operation with no iterations while operating as a utility line current regulator. A pulsewidth modulator based on employing PUC5 redundant switching states fixes the PUC5 auxiliary dc bus capacitor voltage to its desired level with no necessity of a regulator; the overall technique reduces system complexity with less sensors and no loops in the predictive algorithm making it suitable for industrial applications. System discrete model is developed and experimental results verify the performance of the designed controller in making a fast response in regulating the grid current and balancing the capacitor voltage. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
9. A Bridge Modular Switched-Capacitor-Based Multilevel Inverter With Optimized SPWM Control Method and Enhanced Power-Decoupling Ability.
- Author
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He, Liangzong and Cheng, Chen
- Subjects
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ELECTRIC inverters , *CONVERTERS (Electronics) , *ELECTRIC current converters , *POWER density , *CAPACITORS - Abstract
Microinverters operating into the single-phase grid from new energy source with low-voltage output face the challenges of efficiency bottleneck and twice-line-frequency variation. This paper proposed a multilevel inverter based on bridge modular switched-capacitor (BMSC) circuits with its superiority in conversion efficiency and power density. The topology is composed of dc–dc and dc–ac stages with independent control for each stage, aiming to improve system stability and simplify the control method. The BMSC dc–dc stage, which can be expanded to synthesize more levels, not only features multilevel voltage gain but also partially replaces the original bulk input capacitor and functions as an active energy buffer to enhance power-decoupling ability between dc and ac sides. In dc–ac stage, the control strategy of optimized unipolar frequency doubling sine-wave pulse width modulation is proposed to improve the quality of output waveform. Meanwhile, the multilevel voltage phase has been optimized to further reduce the power loss. Finally, a prototype has been built and tested. Associated with the simulation, the experimental results validate the practicability of these analyses. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
10. Novel Discontinuous PWM Method of a Three-Level Inverter for Neutral-Point Voltage Ripple Reduction.
- Author
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Lee, June-Seok, Yoo, Seungjong, and Lee, Kyo-Beum
- Subjects
- *
PULSE width modulation transformers , *ELECTRIC inverters , *VOLTAGE regulators , *ELECTRIC waves , *ELECTRIC potential - Abstract
A new pulsewidth modulation (PWM) strategy which is an alternative approach of the discontinuous PWM (DPWM) for a three-level neutral-point-clamped (NPC) inverter is proposed in this paper. A three-level NPC inverter is completely mature and very well-established topology in high-power applications. However, the three-level NPC inverter has an inheritance problem of the neutral-point voltage unbalancing due to the split dc-link capacitors. This structure can cause large neutral-point voltage ripple. Furthermore, output currents of the three-level NPC inverter are distorted by the neutral-point voltage ripple. Therefore, the neutral-point voltage must be controlled. In this paper, a new DPWM method using two different offsets for the neutral-point ripple reduction is proposed and the effectiveness of the proposed DPWM method is verified by using the simulation and the experimental results. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
11. Single-Phase Modified Quasi-Z-Source Cascaded Hybrid Five-Level Inverter.
- Author
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Ho, Anh-Vu and Chun, Tae-Won
- Subjects
- *
ELECTRIC inverters , *VOLTAGE control , *ELECTRIC impedance , *ELECTRONIC modulation , *SWITCHING theory - Abstract
This paper proposes the combination of a novel modified quasi-Z-source (MqZS) inverter with a single-phase symmetrical hybrid three-level inverter in order to boost the inverter three-level output voltage. The proposed single-phase MqZS hybrid three-level inverter provides a higher boost ability and reduces the number of inductors in the source impedance, compared with both the single-phase three-level neural-point clamped quasi-Z-source inverter and the single-phase quasi-Z-source cascaded multilevel inverter. Additionally, it can be extended to obtain the nine-level output voltage by cascading two three-level pulse width modulation switching cells with a separate MqZS and a dc source, which herein is called a single-phase MqZS cascaded hybrid five-level inverter (MqZS-CHI). A modified modulation technique based on an alternative phase opposition disposition scheme is suggested to effectively control the shoot-through state for boosting the dc-link voltage and balancing the two series capacitor voltages of the MqZS. The performances of both the proposed MqZS-CHI and the modulation techniques are verified through simulation and experimental results. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
12. Operation and Control of a Nine-Level Modified ANPC Inverter Topology With Reduced Part Count for Grid-Connected Applications.
- Author
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Sandeep, N. and Yaragatti, Udaykumar R.
- Subjects
- *
ELECTRIC inverters , *TOPOLOGY , *VOLTAGE control , *CAPACITORS , *ELECTRIC switchgear , *POWER supply quality , *RENEWABLE energy sources - Abstract
This paper presents a nine-level active-neutral-point-clamped (ANPC) based multilevel inverter (MLI) topology for grid-connected applications requiring only ten switches. The envisaged structure comprises two parts, namely five-level ANPC unit, and a two-level converter leg whose midpoint is used as another ac terminal. An ad hoc switching state redundancy based modulation strategy is used to ensure that the voltage across the flying capacitor is tightly balanced and is implemented using a look-up table further simplifies the control complexity. The performance and effectiveness of the proposed topology with its control scheme are validated through simulations and experimental tests. Comparison with other MLIs is included to highlight the merits of the proposed topology. From the results, it will be shown that the proposed inverter requires the least part count as compared to other topologies with the same performance and output quality. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
13. A Symmetrical Cascaded Compact-Module Multilevel Inverter (CCM-MLI) With Pulsewidth Modulation.
- Author
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Lee, Sze Sing, Heng, Yeh En, Sidorov, Michail, and Idris, Nik Rumzi Nik
- Subjects
- *
ELECTRIC inverters , *PULSE width modulation transformers , *TOPOLOGY , *SWITCHING circuits , *VOLTAGE control - Abstract
Cascaded H-bridge (CHB) multilevel inverters (MLIs) have been widely used for power electronics systems. While high-voltage blocking across power switches is not a constraint for low voltage applications, the research trend has been oriented to the design of more compact module topologies as an alternative for CHB. Despite the generation of more voltage levels with reduced switch count, the existing module topologies in recent literature take no account of the freewheeling current path during dead-time, thus, inducing multistep jumps in voltage levels and giving rise to undesirable voltage spikes. Addressing this concern, this paper proposes two symmetrical compact-module topologies for cascaded MLI, where freewheeling current path during dead-time is provided for smooth transition between voltage levels to prevent voltage spikes. The proposed 7-level and 13-level compact-modules demonstrated low number of conducting switches for all voltage levels. Comprehensive analysis and comparison with the latest module topologies are conducted. To validate the operation of the proposed compact-module topologies, simulation and experimental results are presented. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
14. Decoupled Control Scheme of Grid-Connected Split-Source Inverters.
- Author
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Abdelhakim, Ahmed, Mattavelli, Paolo, Boscaino, Valeria, and Lullo, Giuseppe
- Subjects
- *
MATHEMATICAL decoupling , *RENEWABLE energy sources equipment , *CONVERTERS (Electronics) , *RENEWABLE energy sources & economics , *ELECTRON tube grids ,DESIGN & construction - Abstract
Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, e.g., the high efficiency, the reduced cost and complexity, and, quite often, the boost capabilities that is usually achieved using a front-end dc–dc boost converter before the inversion stage, leading to a two-stage architecture. Meanwhile, single-stage power conversion systems, which perform the boosting operation within the inversion one, offer some potential advantages, in terms of reducing the complexity and the volume of the whole system. Among several proposed options, the split-source inverter (SSI) has been recently proposed by Abdelhakim et al. as an alternative option with some interesting features to the commonly used Z-source inverter. Taking into account that the SSI is controlled by a single parameter, i.e., its dc and ac sides are controlled by the modulation index, it is of paramount importance to investigate its control scheme in grid-connected mode, which has never been studied yet. Hence, this paper models the SSI dc side and proposes a modified modulation scheme combined with the commonly used synchronous reference frame control technique to achieve a decoupled control scheme of the SSI in grid-connected mode, i.e., the dc and the ac sides of the SSI can be controlled independently, which is convenient for many applications. The introduced control scheme is analyzed and simulated using a MATLAB/Simulink model, where a reduced scale 1-kVA grid-connected SSI is designed and simulated for the sake of experimental validation. Finally, the designed system is implemented experimentally to validate and verify the reported analysis and simulations. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
15. Novel High-Efficiency Three-Level Stacked-Neutral-Point-Clamped Grid-Tied Inverter.
- Author
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Wang, Yong and Li, Rui
- Subjects
- *
DIODES , *HYBRID power systems , *ELECTRIC inverters , *ELECTRIC current converters , *DIRECT currents - Abstract
In recent years, high photovoltaic array voltage up to 1000 V and transformerless grid-tied inverter have been increasingly researched and applied to elevate the inverter and the dc power collection efficiency. With the same reasons, a three-level neutral point clamped (3L-NPC) inverter featuring low power device voltage stress and low leakage current becomes increasingly attractive. In this paper, the operation and the features of a novel grid-tied 3L-NPC are presented. The proposed topology is a derivative of the three-level stacked neutral point clamped (3L-SNPC) structure. However, compared with the conventional 3L-SNPC and its pulse width modulation (PWM) strategy, the new topology with novel PWM strategy features completely inactive intrinsic body diodes. Furthermore, only two outer power devices are working with switching frequency, while the other four Insulated Gate Bipolar Transistors (IGBTs) are actually with the grid frequency. Therefore, the relatively high switching frequency is selected to reduce the inverter output filter inductance. A hybrid CoolMosfet and IGBT power module configuration is also proposed based on the new PWM strategy. The calculation shows that the total power device losses are reduced. The experimental results are illustrated in this paper to confirm the operation of the proposed topology and controller. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
16. Wide Input Voltage Range Photovoltaic Microconverter With Reconfigurable Buck?Boost Switching Stage.
- Author
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Chub, Andrii, Vinnikov, Dmitri, Kosenko, Roman, and Liivik, Elizaveta
- Subjects
- *
DC-to-DC converters , *PHOTOVOLTAIC power systems , *SWITCHING circuits , *VOLTAGE regulators , *DIGITAL control systems - Abstract
This paper presents a novel soft-switching galvanically isolated buck-boost dc–dc converter as a module-integrated converter for photovoltaic (PV) applications. It features three major operating modes: boost, normal, and buck mode. Their proper distribution over the input voltage range enables wide voltage regulation capabilities, i.e., close to those of nonisolated power optimizers. The proposed control algorithm requires only one buck-boost switching stage that performs voltage regulation by means of the switching stage reconfiguration with smooth transition between the modes. The design guidelines and the digital control system for PV applications are provided. The module-integrated converter was verified experimentally with a solar array simulator. The converter showed good maximum power point tracking performance and a peak efficiency of nearly 97%. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
17. A Flying-Capacitor-Clamped Five-Level Inverter Based on Bridge Modular Switched-Capacitor Topology.
- Author
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He, Liangzong and Cheng, Chen
- Subjects
- *
CAPACITORS , *ELECTRIC inverters , *COMPOSITE structures , *DC-to-DC converters , *CAPACITOR switching - Abstract
A novel flying-capacitor-clamped five-level inverter based on bridge modular switched-capacitor topology is proposed in this paper. The inverter features the switched-capacitor circuit with dc–dc boosting conversion ability and the multilevel inverter circuit with flying-capacitor-clamped performance. With the special composite structure, the number of components is cut down compared to the topology of the conventional cascaded multilevel inverter. Meanwhile, part of switches can be operated under line voltage frequency, resulting in switching loss reduction. Hence, the potential of system efficiency and power density is released due to embed switched-capacitor circuit. More importantly, the optimized carrier-based phase disposition pulse width modulation method is employed as a control strategy. Under this control strategy, the capacitor voltage self-balance can be realized and quality of output waveforms can be improved significantly. After simulation, the prototype is built to validate the correctness and practicability of the analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
18. Design and Implementation of Space Vector Modulation-Based Sliding Mode Control for Grid-Connected 3L-NPC Inverter.
- Author
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Sebaaly, Fadia, Vahedi, Hani, Kanaan, Hadi Y., Moubayed, Nazih, and Al-Haddad, Kamal
- Subjects
- *
ELECTRIC filters , *SLIDING mode control , *ELECTRIC power distribution grids , *ELECTRIC current rectifiers , *PHASE shifters - Abstract
This paper presents a closed-loop space vector modulation (SVM)-based sliding mode controller (SMC) for a three-level grid-connected neutral point clamped (3L-NPC) inverter. The nonlinear SMC based on Gao's reaching law has been designed to control the grid current and inject desired amount of active and reactive power into the network. Due to using single dc source at the NPC inverter dc bus, neutral point voltage is controlled through redundant switching states and instantaneous dc voltage feedback integrated into SVM technique. Meanwhile, there is no external voltage controller involved, thus no associated fine tuning issues are existed. The performance of the proposed hybrid controller to inject a desired active/reactive power to the grid is investigated through external perturbations such as change in the line current amplitude/phase shift, ac voltage fluctuation, as well as dc voltage variation. Full converter state-space model was developed and simulated. Experimental results are provided to verify the fast dynamic performance, low content of line current THD%, and good voltage balancing of dc bus capacitors of the NPC inverter. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
19. A Novel Six-Level Inverter Topology for Medium-Voltage Applications.
- Author
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Le, Quoc Anh and Lee, Dong-Choon
- Subjects
- *
ELECTRIC inverters , *CAPACITORS , *ELECTRIC potential , *ELECTRIC currents , *ELECTRICAL engineering - Abstract
In this paper, a novel topology of six-level inverters for a medium-voltage high-power applications is proposed, which consists of inner flying-capacitor inverter (FCI) units and outer two-level inverter units. The proposed topology can reduce the number of devices, components, and isolated sources compared with the existing ones in the case of the same number of output voltage steps, which result in a reduction of the size and weight of the inverters. Also, the total power loss of the proposed topology is lower than that of the diode-clamped inverter (DCI) and FCI. Besides, the estimated cost of the proposed topology is about 60.5% and 81.3% compared with the DCI and FCI, respectively. In addition, the modulation technique and the control strategy for the dc-link capacitor and flying-capacitor voltages are developed for the proposed topology. The effectiveness of the proposed six-level inverter for the medium-voltage applications has been verified by simulation results. Also, the feasibility of the proposed inverter has been proved by experimental results for the prototype at the laboratory. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Finite-Control-Set Model Predictive Control for Grid-Connected Packed-U-Cells Multilevel Inverter.
- Author
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Trabelsi, Mohamed, Bayhan, Sertac, Ghazi, Khalid Ahmed, Abu-Rub, Haitham, and Ben-Brahim, Lazhar
- Subjects
- *
ELECTRIC inverters , *ELECTRIC currents , *ELECTRIC power distribution grids , *ELECTRIC inductors , *ELECTRIC circuits - Abstract
This paper presents a finite-control-set model predictive control (FCS-MPC) for grid-tied packed U cells (PUC) multilevel inverter (MLI). The system under study consists of a single-phase 3-cells PUC inverter connected to the grid through filtering inductor. The proposed competitive topology allows the generation of 7-level output voltage with reduction of passive and active components compared to the conventional MLIs. The aim of the proposed FCS-MPC technique is to achieve, under various operating conditions, grid-tied current injection with unity power factor and low total harmonic distortion while balancing the capacitor voltage. Parameters’ sensitivity analysis was also conducted. The study is conducted on a low-power case study single-phase 3-cells PUC inverter and with possible extension to higher number of cells. Theoretical analysis, simulation, and experimental results are presented and compared. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. A Single DC Source Cascaded Seven-Level Inverter Integrating Switched-Capacitor Techniques.
- Author
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Sun, Xiaofeng, Wang, Baocheng, Zhou, Yue, Wang, Wei, Du, Huiyuan, and Lu, Zhigang
- Subjects
- *
CASCADE converters , *CAPACITOR switching , *ELECTRIC circuits , *ELECTRIC inverters , *DIRECT currents - Abstract
In this paper, a novel cascaded seven-level inverter topology with a single input source integrating switched-capacitor techniques is presented. Compared with the traditional cascade multilevel inverter, the proposed topology replaces all the separate dc sources with capacitors, leaving only one H-bridge cell with a real dc voltage source and only adds two charging switches. The capacitor charging circuit contains only power switches, so that the capacitor charging time is independent of the load. The capacitor voltage can be controlled at a desired level without complex voltage control algorithm and only use the most common carrier phase-shifted sinusoidal pulse width modulation strategy. The operation principle and the charging–discharging characteristic analysis are discussed in detail. A 1-kW experimental prototype is built and tested to verify the feasibility and effectiveness of the proposed topology. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
22. A Predictive Capacitor Voltage Control of a Hybrid Cascaded Multilevel Inverter With a Single DC-Link and Reduced Common-Mode Voltage Operation.
- Author
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Arun Rahul, S., Kaarthik, R. Sudharshan, Gopakumar, K., Franquelo, Leopoldo G., and Leon, Jose I.
- Subjects
- *
VOLTAGE control , *ELECTRIC inverters , *INDUCTION motors , *PREDICTIVE control systems , *PULSE width modulation transformers - Abstract
For cascaded multilevel inverter topologies with a single dc supply, closed-loop capacitor voltage control is necessary for proper operation. This paper presents zero and reduced common-mode voltage (CMV) operation of a hybrid cascaded multilevel inverter with predictive capacitor voltage control. Each phase of the inverter is realized by cascading two- three-level flying capacitor inverters with a half-bridge module in between. For the presented inverter topology, there are redundant switching states for each inverter voltage levels. By using these switching state redundancies, for every sampling instant, a cost function is evaluated based on the predicted capacitor voltages for each phase. The switching state that minimizes cost function is treated as the best and is switched for that sampling instant. The inverter operates with zero CMV for a modulation index upto 86%. For modulation indices from 86% to 96%, the inverter can operate with reduced CMV magnitude (Vdc/18) and reduced CMV switching frequency using the new space-vector pulsewidth modulation (SVPWM) presented herein. As a result, the linear modulation range is increased to 96% as compared to 86% for zero CMV operation. Simulation and experimental results are presented for the inverter topology for various steady state and transient operating conditions by running an induction motor drive with open loop $V/f$ control scheme. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
23. Real-Time Implementation of Model-Predictive Control on Seven-Level Packed U-Cell Inverter.
- Author
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Metri, Julie I., Vahedi, Hani, Kanaan, Hadi Y., and Al-Haddad, Kamal
- Subjects
- *
PREDICTIVE control systems , *ELECTRIC inverters , *CAPACITORS , *ELECTRIC potential , *ELECTRICAL harmonics - Abstract
In this paper, a model-predictive control (MPC) has been designed and implemented on the packed U-cell (PUC) inverter, which has one isolated dc source and one capacitor as an auxiliary dc link. The MPC is designed to regulate the capacitor voltage at the desired magnitude to have seven voltage levels at the output of the inverter. Since grid-connected application is targeted by this application, the inverter should be capable of supplying requested amount of active and reactive power at the point of common coupling (PCC) as well. Therefore, MPC should also consider the line-current control to monitor the exchange of reactive power with the grid while injecting appropriate active power at low total harmonic distortion (THD). Various experimental tests including change in dc-source voltage, active power variation, and operation at different power factor (PF) have been performed on a laboratory prototype to validate the good performance obtained by the proposed MPC. The dynamic performance of the controller during sudden changes in dc capacitor voltage, supply current, and PF demonstrates the fast and accurate response and the superior operation of the proposed controller. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
24. High Step-Up DC–AC Inverter Suitable for AC Module Applications.
- Author
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Arshadi, Sayed Abbas, Poorali, Behzad, Adib, Ehsan, and Farzanehfard, Hosein
- Subjects
- *
ELECTRIC inverters , *DC-AC converters , *ELECTRIC power distribution grids , *PHOTOVOLTAIC power systems , *PERFORMANCE evaluation - Abstract
In this paper, a novel grid-connected high step-up inverter is proposed. The topology is composed of two stages. The first stage is a single-switch high step-up dc–dc converter with bipolar outputs, and the second stage is a conventional half-bridge dc–ac grid-connected inverter. Negative grounding of the photovoltaic (PV) module has resulted in elimination of unwanted ground leakage currents in the PV system. Simple structure, employing few semiconductor switches, simple control, and high efficiency are the features of the proposed topology. Theoretical analysis and principal operation of the circuit are discussed. An experimental prototype is implemented to verify the performance of the proposed inverter. The experimental results confirm the aforementioned features and the theoretical analysis of the converter operation. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
25. Carrier-Based PWM Methods With Common-Mode Voltage Reduction for Five-Phase Coupled Inductor Inverter.
- Author
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Tan, Cheng, Xiao, Dan, Fletcher, John Edward, and Rahman, Muhammed Fazlur
- Subjects
- *
PULSE width modulation , *VOLTAGE control , *ELECTRIC inductors , *ELECTRIC inverters , *ELECTRICAL conductivity transitions - Abstract
Carrier-based pulsewidth-modulation (CBPWM) techniques are popular due to their simplicity, and have been widely researched for various three-phase inverter configurations. In this paper, two CBPWM techniques are proposed to reduce the common-mode (CM) voltage generated by the five-phase inverter. The five-phase inverters have more flexibility in reducing the CM voltage than their three-phase counterparts because they have more phase legs, hence finer control over the star-point voltage of the load. Two methods are proposed for the conventional two-level five-phase inverter to reduce the CM voltage; one utilizing adjacent modulating waveforms and the other utilizing nonadjacent modulating waveforms. The coupled inductor inverter (CII) uses coupled inductors to generate multilevel outputs. As the volt-second balance must be maintained across each coupled inductor, direct application of the proposed methods on the CII inverter will result in overcurrents in the coupled inductors. Hence, the proposed methods are further improved to ensure the volt-second integral over each switching period is zero. Moreover, the two proposed methods are designed to reduce switching events and prevent unexpected states occurring during the switching transitions. The performance and the switching strategy of both methods are verified by both simulations and experiments on a prototype of five-phase CII. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
26. Novel Modular Multiple-Input Bidirectional DC–DC Power Converter (MIPC) for HEV/FCV Application.
- Author
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Hintz, Andrew, Prasanna, Udupi R., and Rajashekara, Kaushik
- Subjects
- *
DC-to-DC converters , *ELECTRIC power conversion , *ELECTRIC current converters , *HYBRID electric car research , *ELECTRIC vehicles - Abstract
This paper proposes a novel multiple-input bidirectional dc–dc power converter to interface more than two dc sources of different voltage levels. This finds applications in hybrid electric/fuel cell vehicles (FCVs), where different dc sources of unequal voltage levels need to be connected with bidirectional power flow capability. The converter can be used to operate in both the buck and boost modes with bidirectional power control. It is also possible to independently control power flow between any two sources when more than two sources are actively transferring power in either directions. The operation, analysis, and design of the converter are presented with different modes of power transfer. The proposed converter is demonstrated for FCV application using real-time hardware-in-the-loop system. Experimental results for a 5-kW system are presented, validating the theoretical analysis. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
27. Hybrid Multilevel Inverter Using Switched Capacitor Units.
- Author
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Babaei, Ebrahim and Gowgani, Saeed Sheermohammadzadeh
- Subjects
- *
ELECTRIC inverters , *CAPACITORS , *TOPOLOGY , *ENERGY storage , *ELECTRIC equipment - Abstract
In this paper, two new topologies are proposed for multilevel inverters. The proposed topologies consist of a combination of the conventional series and the switched capacitor inverter units. The proposed topologies reduce the number of switches and isolated dc voltage sources, the variety of the dc voltage source values, and the size and cost of the system in comparison with the conventional topologies. In addition, the proposed topologies can double the input voltage without a transformer. There is no need for complicated methods to balance the capacitor voltage. The simulation and experimental results of single-phase 25- and 17-level inverters are given to prove the correct operation of the proposed topologies. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
28. A Novel Multilevel Inverter Based on Switched DC Sources.
- Author
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Gupta, Krishna Kumar and Jain, Shailendra
- Subjects
- *
ELECTRIC inverters , *HARMONIC distortion (Physics) , *DIRECT currents , *VOLTAGE control , *INTEGRATED circuits , *FAULT-tolerant control systems - Abstract
This paper presents a multilevel inverter that has been conceptualized to reduce component count, particularly for a large number of output levels. It comprises floating input dc sources alternately connected in opposite polarities with one another through power switches. Each input dc level appears in the stepped load voltage either individually or in additive combinations with other input levels. This approach results in reduced number of power switches as compared to classical topologies. The working principle of the proposed topology is demonstrated with the help of a single-phase five-level inverter. The topology is investigated through simulations and validated experimentally on a laboratory prototype. An exhaustive comparison of the proposed topology is made against the classical cascaded H-bridge topology. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
29. Pulsewidth Modulation of Z-Source Inverters With Minimum Inductor Current Ripple.
- Author
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Tang, Yu, Xie, Shaojun, and Ding, Jiudong
- Subjects
- *
ELECTRONIC modulation , *ELECTRIC inverters , *ELECTRIC inductors , *CIRCUIT elements , *SIMULATION methods & models - Abstract
This paper proposes the pulsewidth modulation (PWM) strategy of Z-source inverters (ZSIs) with minimum inductor current ripple. In existing PWM strategy with single-phase shoot-through, the shoot-through time interval is divided into six equal parts, therefore the three phase legs bear the equal shoot-through time interval. In this manner, the allotment and arrangement of the shoot-through state is easy to realize, but the inductor current ripple is not optimized. This causes to use relatively large inductors. In the proposed PWM strategy, the shoot-through time intervals of three phase legs are calculated and rearranged according to the active state and zero state time intervals to achieve the minimum current ripple across the Z-source inductor, while maintaining the same total shoot-through time interval. The principle of the proposed PWM strategy is analyzed in detail, and the comparison of current ripple under the traditional and proposed PWM strategy is given. Simulation and experimental results on the series ZSI are shown to verify the analysis. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
30. A Nine-Level Inverter Topology for Medium-Voltage Induction Motor Drive With Open-End Stator Winding.
- Author
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Rajeevan, P. P., Sivakumar, K., Gopakumar, K., Patel, Chintan, and Abu-Rub, Haitham
- Subjects
- *
INDUCTION motors , *INDUCTION machinery , *STATORS , *CONVERTERS (Electronics) , *BRUSHLESS electric motors - Abstract
A new scheme for nine-level voltage space-vector generation for medium-voltage induction motor (IM) drives with open-end stator winding is presented in this paper. The proposed nine-level power converter topology consists of two conventional three-phase two-level voltage source inverters powered by isolated dc sources and six floating-capacitor-connected H-bridges. The H-bridge capacitor voltages are effectively maintained at the required asymmetrical levels by employing a space vector modulation (SVPWM) based control strategy. An interesting feature of this topology is its ability to function in five- or three-level mode, in the entire modulation range, at full-power rating, in the event of any failure in the H -bridges. This feature significantly improves the reliability of the proposed drive system. Each leg of the three-phase two-level inverters used in this topology switches only for a half cycle of the reference voltage waveform. Hence, the effective switching frequency is reduced by half, resulting in switching loss reduction in high-voltage devices. The transient as well as the steady-state performance of the proposed nine-level inverter-fed IM drive system is experimentally verified in the entire modulation range including the overmodulation region. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
31. Assessing the Benefits of Hybrid Cycloconverters.
- Author
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Xu, Tianning, Klumpner, Christian, and Clare, Jon
- Subjects
- *
CASCADE converters , *COMMUTATION (Electricity) , *THYRISTORS , *ELECTRIC motors , *PERFORMANCE evaluation , *FORCE & energy , *ELECTRIC inverters , *CAPACITORS , *COMPUTER simulation - Abstract
Power converters consisting of naturally commutated thyristors such as cycloconverters and current source inverters were the first to be used in driving electrical motors with variable speed, but now, due to their inferior performance compared to forced commutated converters, their use is restricted in the high voltage/high power range where the performance and cost of forced commutated switching devices are not yet competitive. Hybrid cycloconverters proposed recently are capable of improving the performance of cycloconverters by adding an auxiliary forced commutated inverter with reduced installed power. It will be shown that the new topology is not only able to improve the quality of the output voltage but is also able to enhance the control over the circulating current and, therefore, for some of the cycloconverter arrangements, to improve the input power quality. This paper evaluates the performance of a few standard and hybrid cycloconverter arrangements using both simulation and experimental results. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
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