34 results on '"ground leakage current"'
Search Results
2. Internal Current Return Path for Ground Leakage Current Mitigation in Current Source Inverters
- Author
-
Emilio Lorenzani, Giovanni Migliazza, Fabio Immovilli, Chris Gerada, He Zhang, and Giampaolo Buticchi
- Subjects
Current source inverter ,photo-voltaic power systems ,ground leakage current ,renewable energy sources ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper analyzes in detail the effect of a simple solution for ground leakage current mitigation applicable to transformerless three-phase current source inverter (CSI). The circuit modification solution is assessed for both traditional CSI topology and for CSI with an additional seventh switch, in literature named CSI7 (or H7), in particular with the splitting of the dc input inductance. In the present work, the solution is applied to grid-connected converters for string photovoltaic applications: scope of the circuit modification is to provide an internal return path from the wye connected capacitors of the output CL filter. This additional return path is able to significantly reduce the ground leakage current without adversely affecting THD. The performance of the proposed solution is assessed by the numerical simulations in case of a string of photovoltaic (PV) modules and the different behavior of CSI and CSI7 topologies is thoroughly investigated. Furthermore, the definition of VcmZC is assessed by applying it to the common mode equivalent circuits for CSI7 with additional return path and their validation by means of a two-step simulation. The simulation results and experimental validation shows good agreement and confirm that the proposed solution is able to strongly reduce the ground leakage current.
- Published
- 2019
- Full Text
- View/download PDF
3. Mitigation of Ground Leakage Current of Single-Phase PV Inverter Using Hybrid PWM With Soft Voltage Transition and Nonlinear Output Inductor.
- Author
-
Shen, Ruihua and Chung, Henry Shu-Hung
- Subjects
- *
LEAKAGE , *ELECTRIC power , *PULSE width modulation transformers - Abstract
A single-phase transformerless full-bridge photovoltaic grid-tie inverter is presented. It utilizes 1) a virtual ground technique to mitigate ground leakage current, 2) a hybrid pulsewidth modulation (HPWM) scheme to profile the output current and prevent sudden changes in the common-mode voltage, and 3) a nonlinear output inductor to attenuate current ripple around zero crossings and minimize filter size. The HPWM is effectively the same as unipolar PWM (UPWM), but with soft voltage transition modulation introduced around the zero crossings. Apart from low switching losses, the output filter is implemented with a minimum number of components to achieve high attenuation of ripple current. By deriving the switching trajectory, a mathematical model is formulated, and the ground leakage current and the output current with the traditional UPWM and the proposed HPWM schemes are compared. The output current harmonics caused by the nonlinear output inductor is analyzed by the Volterra theory. A 340 W, 380 Vdc/110 V ac, 50 Hz prototype has been built and evaluated. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. Effect of Semiconductor Parasitic Capacitances on Ground Leakage Current in Three-Phase Current Source Inverters
- Author
-
Giovanni Migliazza, Emilio Carfagna, Giampaolo Buticchi, Fabio Immovilli, and Emilio Lorenzani
- Subjects
current source inverter ,photovoltaic ,parasitic capacitance ,common mode ,ground leakage current ,Technology - Abstract
This paper investigates the influence of power semiconductor parasitic components on the ground leakage current in the three-phase Current Source Inverter topology, in the literature called H7 or CSI7. This topology allows reducing converter conduction losses with respect to the classic CSI, but at the same time makes the topology more susceptible to the parasitic capacitances of the semiconductors devices. In the present work, a grid-connected converter for photovoltaic power systems is considered as a case study, to investigate the equivalent circuit for ground leakage current. The same analysis can be extended to applications regarding electric drives, since the HF model of electric machines is characterized by stray capacitance between windings and the stator slots/motor frame. Simulation results proved the correctness of the proposed simplified common-mode circuit and highlighted the need of an additional common-mode inductor filter in case of resonance frequencies of the common-mode circuit close to harmonics of the power converter switching frequency. Experimental results are in agreement with the theoretical analysis.
- Published
- 2021
- Full Text
- View/download PDF
5. Reducing Common-Mode Voltage and Bearing Currents in Quasi-Resonant DC-Link Inverter.
- Author
-
Turzynski, Marek and Chrzan, Piotr J.
- Subjects
- *
ELECTRIC inverters , *ELECTRIC potential , *INDUCTION motors , *INDUCTION machinery , *PULSE width modulation transformers , *ZERO voltage switching , *VOLTAGE control - Abstract
In this article, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is re-examined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the article is to show an advantage of the proposed topology in limiting high-frequency common-mode voltage and bearing currents. In the laboratory setup, an induction machine was equipped with hybrid ceramic bearings and an insulated clutch to measure the shaft-to-frame bearing voltage and the shaft-grounding current. Experimental tests of the PQRDCLI confirm significant reduction of common-mode voltage and shaft-to-frame bearing voltage at dc-link zero voltage notches. By controlling the output voltage slopes, the shaft-grounding brush current and the ground leakage current are also reduced. The efficiency measurement and evaluation of the proposed topology, as compared with a two-level hard switched inverter, reveal comparable efficiency of around 95% and indicate loss distributions in both inverters. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
6. Parallel voltage sag compensator without an injection transformer.
- Author
-
Choi, Woo-Young, Yang, Min-Kwon, and Kim, Yu-Jin
- Abstract
A parallel voltage sag compensator (PVSC) is a power electronics device to compensate the voltage sag and interruption. The conventional PVSC uses an energy storage device and a bidirectional inverter with an injection transformer. However, the injection transformer reduces the power efficiency with high power losses. This paper proposes a PVSC without the injection transformer. The proposed PVSC has a bidirectional DC–DC converter to transfer the electrical power between the energy storage device and the bidirectional inverter. It uses the common-mode filter capacitors for the AC-side filter in the bidirectional inverter. The ground leakage current can be effectively suppressed between the energy storage device and the AC voltage. The proposed system has high power efficiency and low ground leakage current. Experimental results are discussed to evaluate the performance of the proposed system. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
7. 血液透析机电气安全质量控制研究.
- Author
-
杨悦, 李真, and 侍伟伟
- Abstract
Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
8. A Review of Reduction Methods of Impact of Common-Mode Voltage on Electric Drives
- Author
-
Marek Turzyński and Piotr Musznicki
- Subjects
common-mode voltage ,AC drive ,voltage gradient ,ground leakage current ,bearing current ,common-mode disturbances ,Technology - Abstract
In this survey paper, typical solutions that focus on the reduction in negative effects resulting from the common-mode voltage influence in AC motor drive applications are re-examined. The critical effectiveness evaluation of the considered methods is based on experimental results of tests performed in a laboratory setup with an induction machine fed by an inverter. The capacity of a common-mode voltage level reduction and voltage gradient du/dt limitation is discussed to extend motor bearings’ lifetime and increase motor windings’ safety. The characteristic features of the described solutions are compared and demonstrated using laboratory results.
- Published
- 2021
- Full Text
- View/download PDF
9. A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters
- Author
-
M. Pakdel and S. Jalilzadeh
- Subjects
common-mode voltage (cmv) ,grid-connected inverter ,ground leakage current ,neutral point clamped (npc) topology ,photovoltaic (pv) generation system ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Technology (General) ,T1-995 ,Information technology ,T58.5-58.64 - Abstract
This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC) topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM) will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.
- Published
- 2017
- Full Text
- View/download PDF
10. Transformerless Line-Interactive UPS With Low Ground Leakage Current.
- Author
-
Choi, Woo-Young and Yang, Min-Kwon
- Subjects
- *
UNINTERRUPTIBLE power supply , *EFFICIENCY of power amplifiers , *PULSE width modulation , *STRAY currents , *ELECTRIC inverters , *ELECTRIC potential - Abstract
This paper proposes a transformerless line-interactive uninterruptible power supply (UPS) with low ground leakage current. A high-efficiency bidirectional inverter is suggested, which performs the line-interactive UPS functions with low ground leakage current. It has a full-bridge inverter and a bidirectional switch, which operate with the unipolar pulsewidth modulation. Because the bidirectional switch operates at the line-frequency, switching losses can be lower than the previous transformerless inverters. As the inverter operates, the parasitic capacitance between the inverter and the ac voltage ground is clamped to zero voltage for a positive line cycle and to the ac voltage for a negative line cycle, respectively. Thus, the parasitic capacitance can be prevented from being charged or discharged, which ensures the absence of the ground leakage current. The operation modes of the proposed system are described. The control schemes are presented to design the proposed inverter for the line-interactive UPS. Experimental results for a 2.0 kW prototype are discussed to verify the performance of the proposed system. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
11. The First Commercial Brain–Computer Interface Environment
- Author
-
Guger, Christoph, Edlinger, Günter, Graimann, Bernhard, editor, Pfurtscheller, Gert, editor, and Allison, Brendan, editor
- Published
- 2010
- Full Text
- View/download PDF
12. CSI7: A Modified Three-Phase Current-Source Inverter for Modular Photovoltaic Applications.
- Author
-
Lorenzani, Emilio, Immovilli, Fabio, Migliazza, Giovanni, Bianchini, Claudio, Davoli, Matteo, and Frigieri, Matteo
- Subjects
- *
ELECTRIC inverters , *PHOTOVOLTAIC power systems , *CLOSED loop systems , *IDEAL sources (Electric circuits) , *SIMULATION methods & models - Abstract
This paper analyzes the performance of a grid-tied, wide power range, transformerless, modified three-phase current-source inverter (CSI), named CSI7. The CSI7 topology is here analyzed along with a suitable space vector modulation strategy able to attenuate the excitation of the output CL filter. The theoretical analysis and simple analytic expressions highlighted the performance and limitations of the topology when employed as a single-stage photovoltaic (PV) inverter, with a particular emphasis on injected grid current distortion and ground leakage current values. The inverter wide input range allows interfacing PV strings of different module count with a simple closed-loop control. The principle of operation and control is described; the viability of the CSI7 topology was assessed with simulations and extensive experiments on a full-size laboratory prototype. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
13. A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters.
- Author
-
Pakdel, Majid and Jalilzadeh, Saeid
- Subjects
PHOTOVOLTAIC power systems ,ELECTRIC inverters ,SHORT circuits ,IDEAL sources (Electric circuits) ,ENERGY consumption - Abstract
This paper presents a novel neutral point clamped fullbridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC) topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM) will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
14. Effect of Semiconductor Parasitic Capacitances on Ground Leakage Current in Three-Phase Current Source Inverters
- Author
-
Emilio Carfagna, Giampaolo Buticchi, Emilio Lorenzani, Fabio Immovilli, and Giovanni Migliazza
- Subjects
Technology ,Control and Optimization ,Parasitic capacitance ,parasitic capacitance ,Common mode ,Energy Engineering and Power Technology ,ground leakage current ,Topology (electrical circuits) ,Inductor ,common mode ,current source inverter ,photovoltaic ,Electric power system ,Hardware_INTEGRATEDCIRCUITS ,Electrical and Electronic Engineering ,Current source inverter ,Engineering (miscellaneous) ,Ground leakage current ,Photovoltaic ,Physics ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,Current source ,Three-phase ,Harmonics ,Equivalent circuit ,business ,Energy (miscellaneous) - Abstract
This paper investigates the influence of power semiconductor parasitic components on the ground leakage current in the three-phase Current Source Inverter topology, in the literature called H7 or CSI7. This topology allows reducing converter conduction losses with respect to the classic CSI, but at the same time makes the topology more susceptible to the parasitic capacitances of the semiconductors devices. In the present work, a grid-connected converter for photovoltaic power systems is considered as a case study, to investigate the equivalent circuit for ground leakage current. The same analysis can be extended to applications regarding electric drives, since the HF model of electric machines is characterized by stray capacitance between windings and the stator slots/motor frame. Simulation results proved the correctness of the proposed simplified common-mode circuit and highlighted the need of an additional common-mode inductor filter in case of resonance frequencies of the common-mode circuit close to harmonics of the power converter switching frequency. Experimental results are in agreement with the theoretical analysis.
- Published
- 2021
15. High Step-Up DC–AC Inverter Suitable for AC Module Applications.
- Author
-
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
16. Design and Implementation of New Topology for Solar PV Based Transformerless Forward Microinverter
- Author
-
Premkumar, M. and Sumithira, T. R.
- Published
- 2019
- Full Text
- View/download PDF
17. CSI and CSI7 current source inverters for modular transformerless PV inverters
- Author
-
Giovanni Migliazza, Emilio Lorenzani, Giampaolo Buticchi, and Fabio Immovilli
- Subjects
Total harmonic distortion ,business.industry ,Computer science ,Current source inverter ,Ground leakage current ,Photo-voltaic power systems ,Renewable energy sources ,Photovoltaic system ,Energy Engineering and Power Technology ,Modular design ,Converters ,Current source ,Network topology ,Control and Systems Engineering ,Robustness (computer science) ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Space vector modulation - Abstract
Current source inverter (CSI) is a class of power electronic converters that, thanks to the inherent boost capability and ease of control, is investigated for grid-tied photovoltaic power conversion applications. Traditional CSI and CSI7 topologies are here analyzed and compared with two kind of space vector modulation strategies mainly in terms of ground leakage current both in simulations and experiments. Furthermore, THD of the injected grid current and the computation of conduction and switching semiconductor power losses are also carried out in numerical simulations. The topology comparison is carried out with the use of a different number of PV modules, to analyze the robustness of the topologies to different size of the PV strings. Simulation and experimental results show that the CSI7 topology, with respect to conventional CSI, allows to strongly reduce ground leakage current, phase current THD and semicondutor power losses, at the price of an additional power device.
- Published
- 2019
18. Investigation of common-mode voltage and ground leakage current of grid-connected transformerless PV inverter topology.
- Author
-
Raji, Atanda K. and Kahn, Mohamed T. E.
- Subjects
- *
ELECTRIC inverters , *ELECTRIC potential , *LIQUID hydrocarbons , *PHOTOVOLTAIC cells , *STRAY currents , *SOLAR energy , *TOPOLOGY - Abstract
The problems of increasing electricity demand by the unabated population and economy growth can be solved by employing sustainable distributed generation technologies. Convectional primary energy sources such as coal, liquid hydrocarbons' and natural gasses create environmental degradation and energy security problems. Even though the cost of solar energy is zero, the same cannot be said of a solar energy system. The system cost especially the initial capital investment has been hindering the rapid deployment of solar energy systems. One way of reducing the system cost of a solar energy system is to look into the constituent components and see where cost can be reduced without compromising the system efficiency and human safety. Eliminating the isolation transformer reduces the cost and increases the system overall efficiency. However, the galvanic connection between the PV array and the utility grid creates a safety problem for people and system equipment. We present a simplified model for the investigation of the common mode voltage and ground leakage current that can lead to electromagnetic interference. The leakage current level is used for the determination of the suitability of the investigated PV inverter topology for grid connection without isolation transformer. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
19. Experimental Discussions on a Shaft End-to-End Voltage Appearing in an Inverter-Driven Motor.
- Author
-
Shami, Umar Tabrez and Akagi, Hirofumi
- Subjects
- *
INDUCTION motors , *ELECTRIC breakdown , *ELECTRIC conductivity , *CAPACITANCE meters , *ELECTRIC capacity - Abstract
This paper addresses shaft end-to-end and shaft-to-frame voltages that appear in the 400-V, 15-kW induction motor driven by a voltage-source pulsewidth modulation (PWM) inverter. A shaft-to-frame voltage can be observed at either shaft end with respect to the grounded motor frame. A shaft end-to-end voltage can be observed as a voltage difference between the shaft-to-frame voltage at the drive end (DE) and that at the nondrive end (NDE). Experimental waveforms lead to the following interesting observations: motor internal coupling and parasitic capacitance, along with the high-frequency common-mode voltage generated by the PWM inverter, cause a shaft-to-frame voltage with a peak of 8 Vat both DE and NDE. When the shaft-to-frame voltage at either DE or NDE exceeds a dielectric breakdown voltage of thin bearing lubricating grease films, a shaft end-to-end voltage with a peak of 2 V and a width of 30 ns occurs along the motor shaft. This paper makes experimental discussions on the shaft end-to-end voltage generation. Installing a differential-mode filter and/or a common-mode filter on the motor drive system gives a hint on the mechanisms of the occurrence of the shaft end-to-end voltage. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
20. Effect of Semiconductor Parasitic Capacitances on Ground Leakage Current in Three-Phase Current Source Inverters.
- Author
-
Migliazza, Giovanni, Carfagna, Emilio, Buticchi, Giampaolo, Immovilli, Fabio, and Lorenzani, Emilio
- Subjects
- *
STRAY currents , *PHOTOVOLTAIC power systems , *ELECTRIC capacity , *POWER semiconductors , *PHOTOVOLTAIC power generation , *SEMICONDUCTOR devices , *ELECTRIC current rectifiers , *SUBSTRATE integrated waveguides - Abstract
This paper investigates the influence of power semiconductor parasitic components on the ground leakage current in the three-phase Current Source Inverter topology, in the literature called H7 or CSI7. This topology allows reducing converter conduction losses with respect to the classic CSI, but at the same time makes the topology more susceptible to the parasitic capacitances of the semiconductors devices. In the present work, a grid-connected converter for photovoltaic power systems is considered as a case study, to investigate the equivalent circuit for ground leakage current. The same analysis can be extended to applications regarding electric drives, since the HF model of electric machines is characterized by stray capacitance between windings and the stator slots/motor frame. Simulation results proved the correctness of the proposed simplified common-mode circuit and highlighted the need of an additional common-mode inductor filter in case of resonance frequencies of the common-mode circuit close to harmonics of the power converter switching frequency. Experimental results are in agreement with the theoretical analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
21. A Passive EMI Filter for Eliminating Both Bearing Current and Ground Leakage Current From an Inverter-Driven Motor.
- Author
-
Akagi, Hirofumi and Tamura, Shunsuke
- Subjects
- *
ELECTROMAGNETIC interference , *ELECTRIC interference , *ELECTRIC noise , *DIELECTRICS , *POWER electronics , *STRAY currents , *ELECTRIC currents - Abstract
This paper presents a practical approach to eliminating both bearing current and ground leakage current from an inverter-driven motor rated at 400 V and 3.7 kW. When the shaft voltage with respect to the motor frame exceeds the dielectric breakdown voltage of thin lubricating grease films in two metal bearings at the drive and non-drive ends, an electrical discharge machining (EDM) current flows through the bearings. A passive electromagnetic interference (EMI) filter can keep the shaft voltage in check, as a result of having eliminated high-frequency common-mode voltage from the motor terminals. Hence, no dielectric breakdown occurs in the grease films, so that no EDM current flows in the bearings. Experimental results verify the viability and effectiveness of the passive EMI filter designed in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
22. A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters
- Author
-
Majid Pakdel and Saeid Jalilzadeh
- Subjects
Engineering ,common-mode voltage (CMV) ,photovoltaic (PV) generation system ,lcsh:T58.5-58.64 ,business.industry ,lcsh:Information technology ,Photovoltaic system ,neutral point clamped (NPC) topology ,ground leakage current ,Topology (electrical circuits) ,Grid ,Network topology ,Topology ,Power (physics) ,lcsh:TA1-2040 ,lcsh:Technology (General) ,Full bridge ,lcsh:T1-995 ,Point (geometry) ,grid-connected inverter ,business ,lcsh:Engineering (General). Civil engineering (General) ,Voltage - Abstract
This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC) topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM) will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.
- Published
- 2017
23. Investigation of common-mode voltage and ground leakage current of grid-connected transformerless PV inverter topology
- Author
-
Atanda K. Raji and Mohamed Tariq Kahn
- Subjects
lcsh:GE1-350 ,education.field_of_study ,Engineering ,Isolation transformer ,General Computer Science ,Primary energy ,business.industry ,common-mode voltage ,Photovoltaic system ,Population ,Electrical engineering ,ground leakage current ,grid-connected transformerless PV inverter topology ,Solar energy ,General Energy ,lcsh:Energy conservation ,Distributed generation ,Grid-connected photovoltaic power system ,Grid connection ,lcsh:TJ163.26-163.5 ,business ,education ,lcsh:Environmental sciences - Abstract
The problems of increasing electricity demand by the unabated population and economy growth can be solved by employing sustainable distributed generation technologies. Convectional primary energy sources such as coal, liquid hydrocarbons’ and natural gasses create environmental degradation and energy security problems. Even though the cost of solar energy is zero, the same cannot be said of a solar energy system. The system cost especially the initial capital investment has been hindering the rapid deployment of solar energy systems. One way of reducing the system cost of a solar energy system is to look into the constituent components and see where cost can be reduced without compromising the system efficiency and human safety. Eliminating the isolation transformer reduces the cost and increases the system overall efficiency. However, the galvanic connection between the PV array and the utility grid creates a safety problem for people and system equipment. We present a simplified model for the investigation of the common mode voltage and ground leakage current that can lead to electromagnetic interference. The leakage current level is used for the determination of the suitability of the investigated PV inverter topology for grid connection without isolation transformer.
- Published
- 2017
24. An Approach to Eliminating High-Frequency Shaft Voltage and Ground Leakage Current From an Inverter-Driven Motor.
- Author
-
Akagi, Hirofumi and Doumoto, Takafumi
- Subjects
- *
ELECTROMAGNETIC interference , *ELECTRIC leakage , *ELECTRIC currents , *ALTERNATING current machinery , *MOTORS , *ELECTRIC inverters - Abstract
This paper proposes a small-sized passive electromagnetic interference (EMI) filter for the purpose of eliminating high-frequency shaft voltage and ground leakage current from an ac motor driven by a voltage-source pulsewidth-modulation inverter. The filter requires access to the neutral point of the motor. A common-mode inductor is connected between the inverter and the motor. The neutral point of the motor is connected to the dc-bus midpoint via a resistor. The dc-bus midpoint is created by using two capacitors in series across the dc positive and negative buses. This unique circuit configuration makes the common-mode inductor effective in reducing the common-mode voltage appearing at the motor terminals. The validity and effectiveness of the EM! filter is verified by experimental results obtained from a 5-kVA laboratory system. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
25. Internal Current Return Path for Ground Leakage Current Mitigation in Current Source Inverters
- Author
-
Chris Gerada, He Zhang, Emilio Lorenzani, Fabio Immovilli, Giampaolo Buticchi, and Giovanni Migliazza
- Subjects
General Computer Science ,Computer science ,020209 energy ,ground leakage current ,Topology (electrical circuits) ,02 engineering and technology ,Current source inverter ,photo-voltaic power systems ,renewable energy sources ,Inductor ,law.invention ,Control theory ,law ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Current source inverter, Photo-voltaic power systems, Ground leakage current, Renewable energy sources ,Leakage (electronics) ,Total harmonic distortion ,business.industry ,020208 electrical & electronic engineering ,Photovoltaic system ,General Engineering ,Current source ,Renewable energy ,Inductance ,Capacitor ,Equivalent circuit ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,business ,lcsh:TK1-9971 - Abstract
This paper analyzes in detail the effect of a simple solution for ground leakage current mitigation applicable to transformerless three-phase current source inverter (CSI). The circuit modification solution is assessed for both traditional CSI topology and for CSI with an additional seventh switch, in literature named CSI7 (or H7), in particular with the splitting of the dc input inductance. In the present work, the solution is applied to grid-connected converters for string photovoltaic applications: scope of the circuit modification is to provide an internal return path from the wye connected capacitors of the output CL filter. This additional return path is able to significantly reduce the ground leakage current without adversely affecting THD. The performance of the proposed solution is assessed by the numerical simulations in case of a string of photovoltaic (PV) modules and the different behavior of CSI and CSI7 topologies is thoroughly investigated. Furthermore, the definition of V-{cmZC} is assessed by applying it to the common mode equivalent circuits for CSI7 with additional return path and their validation by means of a two-step simulation. The simulation results and experimental validation shows good agreement and confirm that the proposed solution is able to strongly reduce the ground leakage current. © 2013 IEEE.
- Published
- 2019
26. A Review of Reduction Methods of Impact of Common-Mode Voltage on Electric Drives.
- Author
-
Turzyński, Marek and Musznicki, Piotr
- Subjects
- *
VOLTAGE , *ELECTRIC drives , *ALTERNATING current electric motors , *STRAY currents , *EVALUATION methodology - Abstract
In this survey paper, typical solutions that focus on the reduction in negative effects resulting from the common-mode voltage influence in AC motor drive applications are re-examined. The critical effectiveness evaluation of the considered methods is based on experimental results of tests performed in a laboratory setup with an induction machine fed by an inverter. The capacity of a common-mode voltage level reduction and voltage gradient du/dt limitation is discussed to extend motor bearings' lifetime and increase motor windings' safety. The characteristic features of the described solutions are compared and demonstrated using laboratory results. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction
- Author
-
Michal Frivaldsky and Marek Turzyński
- Subjects
Control and Optimization ,Computer science ,020209 energy ,Energy Engineering and Power Technology ,Topology (electrical circuits) ,02 engineering and technology ,lcsh:Technology ,quasi-resonant DC link inverter ,Reduction (complexity) ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Common-mode signal ,Point (geometry) ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,common-mode voltage ,AC drive ,circuit simulation ,modeling ,voltage gradient ,ground leakage current ,SIMPLE (military communications protocol) ,lcsh:T ,Renewable Energy, Sustainability and the Environment ,020208 electrical & electronic engineering ,Voltage gradient ,Inverter ,Current (fluid) ,Energy (miscellaneous) ,Voltage - Abstract
In this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction methods. Designed models of inverter, induction machine (IM), and cable are simple, thus the methods for parameter extraction are not complicated. Verification of the proposed modeling approach was realized with the use of the the Synopsys (Mountain View, CA, USA) SABER simulator, while simulation results were experimentally verified. Operation principles of the proposed PQRDCLI converter topology are also described. Based on simulation and experimental results, it was confirmed that the proposed PQRDCLI solution represents required performance within the reduction of common-mode voltage and ground current in electric drives. Moreover, comparisons from a simulation complexity point of view have been performed to the existing methods. The evaluation is being shown at the end of the paper. It is confirmed that the presented method is simple, fast, accurate, and robust as well.
- Published
- 2020
28. Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction.
- Author
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Turzyński, Marek and Frivaldsky, Michal
- Subjects
- *
ELECTRIC current grounding , *ELECTRIC potential , *ELECTRIC drives - Abstract
In this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction methods. Designed models of inverter, induction machine (IM), and cable are simple, thus the methods for parameter extraction are not complicated. Verification of the proposed modeling approach was realized with the use of the the Synopsys (Mountain View, CA, USA) SABER simulator, while simulation results were experimentally verified. Operation principles of the proposed PQRDCLI converter topology are also described. Based on simulation and experimental results, it was confirmed that the proposed PQRDCLI solution represents required performance within the reduction of common-mode voltage and ground current in electric drives. Moreover, comparisons from a simulation complexity point of view have been performed to the existing methods. The evaluation is being shown at the end of the paper. It is confirmed that the presented method is simple, fast, accurate, and robust as well. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application
- Author
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Frede Blaabjerg, Jaber Fallah Ardashir, Seyed Hossein Hosseini, Mehran Sabahi, and Yam P. Siwakoti
- Subjects
Engineering ,Common Mode Voltage (CMV) ,business.industry ,020208 electrical & electronic engineering ,Ripple ,Photovoltaic system ,Electrical engineering ,Transformerless inverter ,020206 networking & telecommunications ,Topology (electrical circuits) ,02 engineering and technology ,Single-phase inverter ,LC circuit ,Maximum power point tracking ,law.invention ,Capacitor ,Ground leakage current ,law ,0202 electrical engineering, electronic engineering, information engineering ,Inverter ,Grid-tie inverter ,business ,Grid-tied converter - Abstract
This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the PV source. This results in a constant common-mode voltage and almost zero leakage current. A unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to reduce the output current ripple and the filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration and higher efficiency. The operating principle and analysis of the proposed circuit are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The results obtained clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems.
- Published
- 2016
30. Recent advances in single-phase transformerless photovoltaic inverters
- Author
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Davide Barater, Giovanni Franceschini, Emilio Lorenzani, Carlo Concari, and Giampaolo Buticchi
- Subjects
Engineering ,Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,020208 electrical & electronic engineering ,Photovoltaic system ,Electrical engineering ,02 engineering and technology ,Converters ,photovoltaic power systems ,power grids ,invertors ,leakage currents ,electromagnetic interference ,power semiconductor devices ,power convertors ,single-phase transformerless photovoltaic inverters ,grid-connected PV power systems ,converter topology review ,PV panel technologies ,common-mode voltage ,PV string terminals ,ground leakage current ,time variations ,electric safety ,electromagnetic interference-related problems ,EMI ,international standards ,semiconductor devices ,conversion efficiency evaluation ,single-phase grid-connected equipment ,international regulations ,Electromagnetic interference ,Maximum power point tracking ,Electric power system ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Grid-connected photovoltaic power system ,business ,Galvanic isolation - Abstract
Photovoltaic (PV) power systems have been in the spotlight of scientific research for years. However, this technology is still undergoing developments, and several new architectures are proposed each year. This study describes the main challenges facing grid-connected PV systems without galvanic isolation, then carries out a review of the state-of-the-art of single-phase systems. The converter topology review is focused on the match between the different types of converters and the different PV panel technologies, determined by the common-mode voltage between the PV string terminals and the ground. The ground leakage current, due to time variations of this voltage, is a source of electric safety and electromagnetic interference (EMI)-related problems, and its amplitude is constrained by international standards. The basic principles of operation of the different solutions are described, along with their strengths and drawbacks. Conversion efficiency is evaluated qualitatively comparing the semiconductor power losses. Finally, the future trends regarding semiconductor devices, PV panels and international regulations for single-phase grid-connected equipment are discussed, and indications on how these might steer future research efforts in PV converters are inferred.
- Published
- 2016
31. Digital Control of Actual Grid-Connected Converters for Ground Leakage Current Reduction in PV Transformerless Systems
- Author
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Giampaolo Buticchi, Emilio Lorenzani, Giovanni Franceschini, and Davide Barater
- Subjects
Engineering ,business.industry ,Photovoltaic system ,Electrical engineering ,grid connected converters ,transformerless topologies ,ground leakage current ,actual commutations ,Maximum power point tracking ,Computer Science Applications ,law.invention ,Electric power system ,Capacitor ,Parasitic capacitance ,Control and Systems Engineering ,law ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Galvanic isolation ,Pulse-width modulation ,Information Systems ,Voltage - Abstract
The design of a photovoltaic (PV) grid-connected converter usually comprehends a galvanic isolation between the grid and the photovoltaic panels. Recently, in low power systems, the galvanic isolation has been removed with the aim to increase efficiency and reduce the cost of the converter. Due to the presence of a parasitic capacitance between the photovoltaic cells and the metal frame of the PV panel, usually connected to earth, a high value of common mode current (i.e., ground leakage current) can arise. In order to limit the ground leakage current (which deteriorates the power quality and generates EMI), new converter topologies have been proposed. Their effectiveness is based on the symmetrical (ideal) commutations of the power switches and some of them adopt a further voltage level derived from a capacitive divider of the DC bus voltage. Unfortunately, in actual implementations, asymmetrical power switches transients and variations of this added voltage lead to higher ground leakage current with respect to the ideal case. After a review of the state of the art this paper investigates these two issues and presents a particular solution (based on digital control and PWM strategy) that, in conjunction with a compensation strategy of power switches actual commutations, guarantees low ground leakage current regardless the parameters tolerance of the power circuit. Simulation and experimental results confirm the effectiveness of the proposed solution.
- Published
- 2012
32. Compensation strategy of actual commutations for PV transformerless grid-connected converters
- Author
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Giampaolo Buticchi, Emilio Lorenzani, and Giovanni Franceschini
- Subjects
Engineering ,Isolation transformer ,parasitic capacitance ,photovoltaic cells ,ground leakage current ,galvanic isolation ,law.invention ,Parasitic capacitance ,line transformer ,law ,Electronic engineering ,Power semiconductor device ,PV transformerless grid-connected converters ,photovoltaic field ,Transformer ,actual commutations ,power devices ,photovoltaic power systems ,compensation strategy ,non-ideal switching behavior ,business.industry ,Photovoltaic system ,Converters ,DC-AC power convertors ,power grids ,DC-AC power conversion ,PWM power convertors ,business ,Galvanic isolation ,Pulse-width modulation - Abstract
Photovoltaic grid-connected converters usually embed a high-frequency or a line transformer, which guarantees galvanic isolation between the photovoltaic field and the mains. In order to increase efficiency and reduce the total cost of the system, the transformer has been removed, and special topologies of converter have been studied in order to limit the ground leakage current that arises with the galvanic connection. In fact, the parasitic capacitance between the photovoltaic cells and the metallic frame of the panel allows high ground leakage current (i.e. common mode current) to be injected into the grid. Actual solutions rely heavily on the symmetry of the system to address the problem. This paper presents a novel strategy to compensate for non-ideal switching behavior of power devices, which is immune to layout asymmetries and tolerance of parameters. Simulation results show the feasibility of the proposed solution.
- Published
- 2010
33. A three-phase transformerless Boost inverter for the reduction of common-mode leakage current in photovoltaic applications
- Author
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Georgios I. Orfanoudakis, Eftychios Koutroulis, Michael A. Yuratich, and Suleiman M. Sharkh
- Subjects
Transformerless ,Ground leakage current ,PV inverter ,Common-mode current ,Boost inverter ,Step-up inverter - Abstract
Summarization: Three-phase transformerless photovoltaic (PV) inverters with PV voltage step-up capability are widely used for integrating PV generation to the electric grid. A known issue with transformerless topologies is the generation of common-mode (CM) ground leakage currents. Several inverter topologies and modulation strategies have been proposed to suppress the CM currents below the limits set by relative standards. The proposed inverter topologies commonly have increased component count and lower efficiency than conventional three-phase inverters, while their modified modulation strategies commonly result in lower output voltage quality and DC-bus voltage utilization. This paper presents a new three-phase Boost PV inverter topology which achieves CM leakage current suppression by modifying the Boost converter instead of the three-phase inverter stage. The topology is formed simply with the addition of one diode in the Boost stage. The added diode losses have a minor effect on the overall conversion efficiency, while the inverter can be modulated with conventional modulation strategies, thus retaining a high output voltage/current quality. The structure and operating principle of the proposed topology are presented, and its effectiveness with respect to CM current suppression is demonstrated through simulation results in MATLAB/Simulink. Παρουσιάστηκε στο: 2021 23rd European Conference on Power Electronics and Applications
34. Extended Boost PV inverter topology for the reduction of common-mode leakage current in three-phase applications
- Author
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Michael A. Yuratich, Georgios I. Orfanoudakis, Suleiman M. Sharkh, and Eftychios Koutroulis
- Subjects
Computer science ,business.industry ,020209 energy ,PV inverter ,020208 electrical & electronic engineering ,Photovoltaic system ,Electrical engineering ,Step-up inverter ,02 engineering and technology ,Transformerless ,Three-phase ,Ground leakage current ,Boost converter ,0202 electrical engineering, electronic engineering, information engineering ,Inverter ,Common-mode current ,Boost inverter ,Common-mode signal ,business ,Pulse-width modulation ,Voltage ,Leakage (electronics) - Abstract
Summarization: Photovoltaic (PV) inverters must not generate high levels of common-mode (CM) ground leakage currents, which may flow due to fast variations in their CM voltage. Moreover, a highly desirable feature for PV inverters is their voltage step-up capability, which enables operation with lower DC input voltage levels, thus extending energy harvesting over wider solar irradiance and temperature ranges. This paper presents a new three-phase Boost PV inverter topology and its modulation strategy, designed based on a new concept for suppressing CM leakage currents in three-phase PV inverters. In contrast to past-proposed three-phase step-up topologies, the proposed PV inverter uses a modified Boost converter instead of a transformerless inverter, as well as a modulation strategy generating high-quality PWM voltage. Due to their combined characteristics, the variation of the CM voltage generated by the proposed PV inverter is minimized, which radically improves its CM current suppressing capability. The structure and operating principle of the proposed topology are presented, and its effectiveness with respect to CM current suppression is demonstrated through simulation results in MATLAB/Simulink. Presented on
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