9 results on '"Jalili, Kamran"'
Search Results
2. Design of LCL filters of active-front-end two-level voltage-source converters
- Author
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Jalili, Kamran and Bernet, Steffen
- Subjects
Electric current converters -- Design and construction ,Damping (Mechanics) -- Control ,Electric filters -- Design and construction ,Industrial electronics -- Research ,Electric current converter ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
This paper introduces a new iterative design procedure of L and LCL filters for low-voltage active-front-end PWM two-level voltage source converters. The analytical expression of the converter harmonic voltages by Bessel functions is applied to design the filter parameters for defined maximum grid current harmonics. Different filter designs are derived for various resonance frequencies and inductance split factors of LCL filter. The minimum amount of stored energy of passive components is used to select a final filter design. A voltage-oriented control scheme, including active damping, is applied in the (400 V and 50 kVA) experimental setup. Both simulation and experimental investigations are presented to verify the accuracy of the filter design procedure. Finally, the steady state and transient performance of the active front end with different LCL filters are depicted. Index Terms--Active damping, active front end, LCL filter.
- Published
- 2009
3. Behavior of PWM active front ends in the presence of parallel thyristor converters
- Author
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Jalili, Kamran, Weitendorf, Niels, and Bernet, Steffen
- Subjects
Electric current converters -- Design and construction ,Harmonics (Electric waves) -- Properties ,Pulse-duration modulation -- Methods ,Electric current converter ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
This paper investigates the effects of grid voltage distortions caused by thyristor converters on the steady-state performance of a pulsewidth modulation (PWM) rectifier with dc voltage link for low-voltage applications. The disturbance transfer function of the current control loop is used to analyze the effects of grid distortions. Influences of the current controller, the phase-locked loop parameters, and the filter inductance on the generated current harmonics are presented. For existing grid voltage harmonics, the amplitude of the corresponding current harmonics are determined and compared to measured current harmonics using a 400-V 40-kW test bench consisting of a PWM rectifier with voltage dc link parallel to a 40-kW thyristor converter. Index Terms--Harmonic distortion, pulsewidth modulation (PWM) active front ends, thyristor converters.
- Published
- 2008
4. Comparison of 2.3-kV medium-voltage multilevel converters for industrial medium-voltage drives
- Author
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Krug, Dietmar, Bernet, Steffen, Fazel, Seyed Saeed, Jalili, Kamran, and Malinowski, Mariusz
- Subjects
Electric current converters -- Design and construction ,Power electronics -- Research ,Voltage -- Measurement ,Electric current converter ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
This paper compares the expense of power semiconductors and passive components of a (2.3 kV, 2.4 MVA) two-level, three-level neutral-point-clamped, three-level flying-capacitor, four-level flying-capacitor, and five-level series-connected H-bridge voltage source converter on the basis of the state-of-the-art 6.5-, 3.3-, 2.5-, and 1.7-kV insulated gate bipolar transistors for industrial medium-voltage drives. The power semiconductor losses, the loss distribution, the installed switch power, the design of flying capacitors, and the components of an LC sine filter for retrofit applications are considered. Index Terms--Filter design, medium voltage, multilevel converters, power electronics.
- Published
- 2007
5. Design and comparison of 4-kV neutral-point-clamped, flying-capacitor, and series-connected H-bridge multilevel converters
- Author
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Fazel, Seyed Saeed, Bernet, Steffen, Krug, Dietmar, and Jalili, Kamran
- Subjects
Electric current converters -- Analysis ,Electric current converter ,Semiconductor device ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
This paper describes the design of a (4-kV, 4.16-MVA) three-level neutral-point-clamped-, three-level flying-capacitor-, four-level flying-capacitor-, and nine-level series-connected H-bridge voltage-source converter on the basis of state-of-the-art 6.5-, 4.5-, 3.3- and 1.7-kV insulated gate bipolar transistors. The semiconductor loss distribution and the design of semiconductors and passive components are compared for a medium switching frequency assuming a constant converter efficiency of about 99%. To evaluate the converter characteristics in high switching frequency applications, a second comparison is realized for the maximum switching frequencies assuming a constant expense of semiconductors in all converters. Index Terms--Medium-voltage drives (MVDs), multilevel converters, power electronics.
- Published
- 2007
6. Testing Characteristics of Grid Forming Converters Part IV: Overload Behaviour and Response to Grid Faults.
- Author
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Ernst, Philipp, Singer, Roland, and Jalili, Kamran
- Subjects
RENEWABLE energy sources ,CONVERTERS (Electronics) ,ELECTRIC generators ,STATIC electricity ,VOLTAGE control - Abstract
On the path towards an energy system powered entirely by Renewable Energy Sources (RES), power electronic converters will have to take over more and more functionalities from synchronous generators to ensure a stable and secure operation of the power grid. Moreover, it is widely recognized that the use of Grid Forming Converters (GFC) is necessary to fully meet these requirements. Over the last years, different concepts have been developed to achieve grid forming characteristics of static power converters. The next essential step is to agree on an exact definition and specification of GFC electrical behaviour as well as to define a suitable conformity assessment procedure. For this purpose, a standardized testing guideline for GFC is needed to assess those functionalities, which are relevant for dynamic grid stability. As a British-German joint work of the two research projects Battery-VSM1 and VerbundnetzStabil2, a first draft is currently under progress. This work focuses on the GFC's behaviour regarding overload situations. Those events includes voltage driven, phase jumps as well as RoCoFs. In every case, the GFC needs to retain grid-synchronicity and inject stabilizing current. In this work different tests are proposed in order to evaluate the GFC's response to the those events. [ABSTRACT FROM AUTHOR]
- Published
- 2020
7. Testing Characteristics of Grid Forming Converters Part II: Voltage Source Properties and Contribution to Power Quality.
- Author
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Denninger, Rebekka, Reichert, Stefan, Rogalla, Sönke, and Jalili, Kamran
- Subjects
RENEWABLE energy sources ,ELECTRIC power distribution grids ,CONVERTERS (Electronics) ,STATIC electricity ,ELECTRIC distortion - Abstract
On the path towards an energy system powered entirely by Renewable Energy Sources (RES), power electronic converters will have to take over more and more functionalities from synchronous generators to ensure a stable and secure operation of the power grid. Moreover, it is widely recognized that the use of Grid Forming Converters (GFC) is necessary to fully meet these requirements. Over the last years, different concepts have been developed to achieve grid forming characteristics of static power converters. The next essential step is to agree on an exact definition and specification of GFC electrical behaviour as well as to define a suitable conformity assessment procedure. For this purpose, a standardized testing guideline for GFC is needed to assess those functionalities, which are relevant for dynamic grid stability. As a British-German joint work of the two research projects Battery-VSM1 and VerbundnetzStabil2, a first draft is currently under progress. This work is the second of four papers on testing GFC and focuses on steady state operation. The GFC must demonstrate stable operation in grid-tie mode, load sharing with other sources as well as an appropriate response to unbalances and harmonic distortion. [ABSTRACT FROM AUTHOR]
- Published
- 2020
8. Investigation of Control Concepts for High-Speed Induction Machine Drives and Grid Side Pulse-Width Modulation Voltage Source Converters
- Author
-
Jalili, Kamran, Bernet, S., Mertens, A., and Malinowski, M.
- Subjects
ddc:621.3 ,ddc:620 ,Electrical engineering, Power electronics, Electric drives ,Elektrotechnik, Leistungselektronik, elektrische Antriebe - Abstract
Control of a low voltage ac/dc/ac converter for high-speed induction machine drive applications has been investigated. Such a configuration can be applied, for example, in microturbines and high-speed spindles. Scalar control is usually applied for the control of high-speed drives especially in the case of very high-speed drives. Indirect rotor-flux-oriented control and direct torque control are designed and compared for the control of an exemplary high-speed induction machine drive. The 2L VSC is the most widely applied converter for high-speed drives. However, the 3L-NPC VSC is an attractive topology if drastically increased switching frequencies are required. A detailed comparison between a 2L VSC and a 3L-NPC VSC as the machine side converter of the exemplary high-speed induction machine drive is carried out. Voltage-oriented control is applied for the control of the grid side PWM active front end converter. In several industrial applications PWM active front end converters commonly operate in parallel to thyristor converter fed dc drives. Behavior of the voltage-oriented controlled active front end converter with L-filter in the presence of a parallel thyristor converter is investigated. The design of the LCL-filter components according to the given maximum grid current harmonics (e.g. IEEE-519) is a complex task. So far a precise and clear design procedure has not been presented. A new procedure to design the grid side filter (L- and LCL-filter) is proposed using the analytical expression of the converter voltage harmonics based on Bessel functions to achieve the compliance with the grid standard of IEEE-519. Voltage-oriented control with active damping is used to control the active front end converter with LCL-filter. A simple method is proposed to design the required lead-lag compensator in the active damping loop.
- Published
- 2008
9. Investigation of Control Concepts for High-Speed Induction Machine Drives and Grid Side Pulse-Width Modulation Voltage Source Converters
- Author
-
Bernet, S., Mertens, A., Malinowski, M., Jalili, Kamran, Bernet, S., Mertens, A., Malinowski, M., and Jalili, Kamran
- Abstract
Control of a low voltage ac/dc/ac converter for high-speed induction machine drive applications has been investigated. Such a configuration can be applied, for example, in microturbines and high-speed spindles. Scalar control is usually applied for the control of high-speed drives especially in the case of very high-speed drives. Indirect rotor-flux-oriented control and direct torque control are designed and compared for the control of an exemplary high-speed induction machine drive. The 2L VSC is the most widely applied converter for high-speed drives. However, the 3L-NPC VSC is an attractive topology if drastically increased switching frequencies are required. A detailed comparison between a 2L VSC and a 3L-NPC VSC as the machine side converter of the exemplary high-speed induction machine drive is carried out. Voltage-oriented control is applied for the control of the grid side PWM active front end converter. In several industrial applications PWM active front end converters commonly operate in parallel to thyristor converter fed dc drives. Behavior of the voltage-oriented controlled active front end converter with L-filter in the presence of a parallel thyristor converter is investigated. The design of the LCL-filter components according to the given maximum grid current harmonics (e.g. IEEE-519) is a complex task. So far a precise and clear design procedure has not been presented. A new procedure to design the grid side filter (L- and LCL-filter) is proposed using the analytical expression of the converter voltage harmonics based on Bessel functions to achieve the compliance with the grid standard of IEEE-519. Voltage-oriented control with active damping is used to control the active front end converter with LCL-filter. A simple method is proposed to design the required lead-lag compensator in the active damping loop.
- Published
- 2009
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