-
[show abstract]
[hide abstract]
ABSTRACT: In this paper the benefits of looping the conventional radial distribution system by a series power electronic system to control power flow has been investigated. The conventional radial electrical distribution system will change to loop or even meshed system due to the deregulation of electrical system and connection of Distributed Generation to Medium and Low voltage in future. However looping the feeders in the conventional distribution system has some benefits which are discussed more precisely in this paper. Controlling the power flow between two feeders from different substation by placing a D-SSSC in the connection point will be source of many advantages. These advantages will be voltage regulation, increasing reliability, loss reduction, avoiding congestion in cables and facilitating use of distributed generation. The real data of Tehran electrical distribution network is used as case study to investigate the advantages of looped power flow controller versus conventional radial distribution system.
Power and Energy (PECon), 2010 IEEE International Conference on; 01/2011
-
[show abstract]
[hide abstract]
ABSTRACT: The paper focuses on a new control strategy for improving the availability of power electronic converters based on interleaved structures. By using this strategy, the power electronic converters can continue to work (with reduced output power) in case of power component failure. The paper describes how to adapt the magnetic output filtering structure for this original control strategy. This structure is based on a monolithic coupler or a coupling transformer. Which are usually employed to minimize in a significant way the mass of the converters. They are normally sized to work with a fixed number of phases. Our control strategy induces new constraints on magnetic component, especially saturation problems. To reduce this problem some extra switch are added. Finally an experimental Power electronic converter driven by an FPGA is presented with the experimental results. It shows some experimental results with a 6 phases converter who work with 5 or 4 phases, to simulate one or two converter leg breakdown.
Applied Power Electronics Conference and Exposition (APEC), 2010 Twenty-Fifth Annual IEEE; 03/2010
-
[show abstract]
[hide abstract]
ABSTRACT: This article analyzes the effects of parasitic capacitances in the series connection of IGBT, which exist naturally due to gate driver and power circuit geometry. Two solutions, that can be combined, are proposed to minimize these effects in order to achieve a better voltage balancing. The first one is based on gate driver self-powering technique. The second one is based on a vertical structure assembly of IGBT connected in series. The performance offered by these two complementary solutions is investigated and validated on a series connection of three IGBT in a chopper converter. Both simulation and experimental results show the effectiveness of our approaches.
Applied Power Electronics Conference and Exposition (APEC), 2010 Twenty-Fifth Annual IEEE; 03/2010
-
[show abstract]
[hide abstract]
ABSTRACT: The choice of a set of capacitors for a dc link may be very different depending on the system requirements and user constraints. This paper shows how to achieve the best choice of a hybrid association of electrolytic capacitor and higher frequency technology (polyester for instance). Maximum allowed rms current in the electrolytic capacitor is obviously taken into account. The input filter of a buck converter is chosen as example. Various constraints are considered: voltage ripple, differential-mode electromagnetic-interference level, losses, weight, volume, surface, etc. Objective function for optimization is defined by the user and may be any of the previous parameters. The optimized result consists in the number and the values of components for both capacitor technologies.
IEEE Transactions on Industry Applications 05/2009; · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The paper focuses on a new driving strategy for improving the efficiency of power converters even if they are not used at there nominal power. The converters are using an output filtering structure with magnetical coupling. These filtering structures are usually employed to minimize in a significant way the mass of the converters. These filters are normally sized to work with a fixed number of phases. To optimize the magnetic components, it is necessary to take into account some physical constraint, as the iron sections of the magnetic circuits and saturation problems. These problems are tricky, especially in case of the variation of the number of phase. A new control strategy is presented for interleaved and multilevel structure. Finally converter simulation results are compared with the experimental results. A 1.6 kW (115 V) converter realization is presented.
Applied Power Electronics Conference and Exposition, 2009. APEC 2009. Twenty-Fourth Annual IEEE; 03/2009
-
[show abstract]
[hide abstract]
ABSTRACT: Interconnection of medium voltage grids associated to the modulation of the transmission line impedance can improves system operation and power quality. However it also leads to rise of the short circuit power. To cope with this constraint and make this new distribution scheme a viable alternative to radial distribution in the future, investigations on short-circuit limitation with a particular line's compensator relying on a series connected Voltage Source Converter (VSC) (also called SSSC for Static Synchronized Series Compensator) has been achieved. Short-circuit limitation is also motivated because power systems grow and become more constrained (due to Distributed Generation (DG) widespread). This paper presents a new concept for a combined short-circuits circuit limiter and dynamic series compensator for medium voltage grids. In non-fault use, it is designed to regulate active and reactive power flow in order to optimize grid behavior. Indeed, coordination of several units dispatched thought the grid could lead to more efficient grid exploitation (i.e. grid losses, loop flow, voltage drop reductions). During fault use (short-circuit) it will limit short-circuit currents to protect the grid and itself. Two innovative short-circuit limitation methods have been developed and experimented thanks to a test bench. The significant operation improvement is expected to justify the cost of the new device.
Applied Power Electronics Conference and Exposition, 2008. APEC 2008. Twenty-Third Annual IEEE; 03/2008
-
[show abstract]
[hide abstract]
ABSTRACT: It is well known that power modules must exhibit as low as possible stray inductance. However, the total inductance of a power module is not the only parameter to indicate the electrical quality of the packaging. In this paper, mathematical criteria will be given, which will allow the evaluation of power modules interconnects with regard to several objectives: equal current constraints among the different paralleled dies, power-drive, and even drive-drive interactions.
IEEE Transactions on Power Electronics 02/2006; · 4.65 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper deals with the design of 1 MHz switching frequency boost convert with silicon carbide power Schottky diodes. This application is designed to work as a power factor correction rectifier. With high breakdown voltage, high energy gap and good thermal conductivity, silicon carbide (SiC) is a serious challenger as a new power semiconductor material. Here we analyze switching behavior in order to evaluate losses in such applications. Then, we compare theoretical and experimental results on PFC boost application.
Industry Applications Conference, 2004. 39th IAS Annual Meeting. Conference Record of the 2004 IEEE; 11/2004
-
[show abstract]
[hide abstract]
ABSTRACT: Today, high voltage power semiconductors such as IGBTs, are being developed. As the voltage is increased, local electric fields applied to dielectric materials also increase. Local deterioration of dielectric materials due to partial discharges (PD) may appear and affect the reliability of the whole component. The usual way to detect PD's under ac voltage via electrical measurements is no longer applicable with the pulsed voltage wave shape encountered in power semiconductor applications. This paper presents investigations carried out with optical measurements of PD's in silicone gels, in a typical IGBT module structure. In addition, a very faint light emission is detected below the PD inception voltage. This light can presumably be attributed to an electroluminescence phenomena, such as previously reported in solids or aromatic liquids, and can constitute a non destructive technique that allows to detect the existence of local high fields in the gel.
Solid Dielectrics, 2004. ICSD 2004. Proceedings of the 2004 IEEE International Conference on; 08/2004
-
[show abstract]
[hide abstract]
ABSTRACT: Power module reliability can be increased if problems due to high electric fields can be better understood. This paper proposes a global analysis using finite element simulations. Results are confirmed thanks to optical detection of partial discharge localization. Solutions to reduce field reinforcement are proposed and discussed. A discussion of maximum electric field handled by insulation gel is also provided.
Solid Dielectrics, 2004. ICSD 2004. Proceedings of the 2004 IEEE International Conference on; 08/2004
-
[show abstract]
[hide abstract]
ABSTRACT: The development of high voltage power module using IGBTs leads to serious problems concerning the electric field insulation. The values of these electric fields are very important regarding the capabilities of the dielectric gels used in the power packages. Solutions have to be developed to ensure limited field and good reliability. The aim of this paper is to show the interest of using finite element simulations in association with partial discharge measurements to determine and localize the maximum field values. Some solutions to lower them are also presented.
Industry Applications Conference, 2003. 38th IAS Annual Meeting. Conference Record of the; 11/2003
-
[show abstract]
[hide abstract]
ABSTRACT: Modern power modules will include more and more electronics in the same package as the power semiconductors. The high dV/dt generated in the module originate common mode currents, which can disturb the module, especially the driver. This paper investigates the common mode current generation in several cases (chopper cell, inverter arms, and series association) and brings layout solutions to reduce its effects.
Industry Applications Conference, 2002. 37th IAS Annual Meeting. Conference Record of the; 02/2002
-
[show abstract]
[hide abstract]
ABSTRACT: Among the various solutions for the series association of high power IGBTs, the active clamping circuit insures both protection and voltage balancing, within good reliability and compactness. Therefore, this structure has been chosen to be integrated closed to the IGBTs. The design of this circuit leads to the resolution of a compromise between a good balancing and limited additional losses. The aim of this paper is to optimise this circuit, in order to reduce the losses, in the IGBTs as well as in the active clamping circuit. This design has been validated in a 3 kV 400 A test bench, using three 1.7 kV components in series.
Industry Applications Conference, 2001. Thirty-Sixth IAS Annual Meeting. Conference Record of the 2001 IEEE;
