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The Self Turn-ON influences the turn-ON and short-circuit behaviour of the IGBT. This is a positive feedback by the IGBT on itself and increases its turn-ON speed. The strength of the effect depends on the gate structure's design. Therefore, IGBTs with different gate structures are investigated with TCAD simulations. Additionally, its influence during Fault under Load is investigated.
The Current-Direction Detection based on measurement of the load current can be used as static MOS-Control of the BIGT. As the gate-emitter voltage vge affects the ON-state characteristics of the BIGT in diode forward-conduction mode, it has to be adapted for optimised operation. In order to operate at low static losses vge has to be below threshold voltage in diode forward-conduction mode. The chosen...
This paper introduces a control method for Reverse-Conducting (RC-)IGBTs which reduces the control dead time of RC-IGBT inverters. Switching measurements with 6.5 kV RC-IGBTs concerning the applicability of the introduced control method and the effect of a load current direction change during the desaturation pulse are presented.
The Advanced-ANPC converter is designed to withstand almost every possible short-circuit failure of the semiconductors in comparison to state-of-the-art (A)NPC converters. The idea behind this concept is an additional short-circuit inductor to improve the robustness against faults. The presented investigations within this paper examine all the possible short-circuit situations and their effects for...
This paper is about the design for the control of a cascaded hybrid converter for railway applications. It shows, how to control the converter with considerations of special aspects for the use in rail vehicles. It considers several aspects of reducing THD of the current and reduction of switching losses.
This paper presents the implementation and dynamic analysis of synchronous frame current regulators for Modular Multilevel Converters (MMC) using complex vectors. This includes the design of the Decoupling Physical Input Cross-Coupling (DPICC) for MMC-topologies. With this, the set of differential equation of the MMC can be transformed into the same format that is used for virtually every other Voltage...
Silicon carbide semiconductors offer high switching frequencies for high voltage application which reduces the filter size. The main drawback of high current applications are high turn-on losses. Within this paper an inverter is proposed which uses a quasi-resonant triangular current mode where the MOSFETs are turned on at zero current.
In modern traction drives the transformer causes a high amount of the overall losses. A transformer with lower losses however increases the THD of the output current and the amplitude of the fault current. Two converters will be presented which make the utilization of an enhanced transformer possible.
The impact of converter-based loads on the power system is evaluated based on stability studies. This requires adequate load models. This paper deals with a time-domain model of an electric vehicle battery charger with grid support functionality (so-called controllable load). The dynamic properties of the components of a unidirectional 1,2 kW battery charger with input diode rectifier are discussed...
Offshore wind turbines built at a long distance from public ac-grid are connected via HVDC-transmission. Future HVDC-systems may connect offshore wind farms via uncontrolled diode rectifiers instead of VSC-HVDC converters. Due to this wind turbine inverters must own a grid forming capability. This Paper describes a fault handling strategy for offshore the wind turbines during faults in the ac-offshore...
For improvement of power system stability, a variety of control strategies has been developed for converter-based loads and generators, that regulate the power consumption or generation dependent on the grid frequency. For unsymmetrical and transient grid conditions the effectiveness of these control strategies is highly dependent on the performance of the frequency measurement. This paper compares...
The Self Turn-ON of IGBTs leads to an increased turn-on speed. As far as IGBTs with different threshold voltages are paralleled, collector current imbalances, during turn-on, may occur. The intensity of imbalance depends on the used gate-drive topology, influenced by the Self Turn-ON.
The gate-emitter voltage VGE affects the on-state characteristics of the BIGT in diode forward-conduction mode. While for conventional IGBT with antiparallel free-wheeling diode VGE is at 15 V regardless of current direction, it has to be adapted for the BIGT. The gate-emitter voltage VGE has to be below threshold voltage, in order to operate at low static losses in diode forward-conduction mode....
Future HVDC systems may connect offshore wind farms via uncontrolled diode rectifiers instead of VSC-HVDC converters. Due to this wind turbine inverters must own a grid forming capability. This paper describes a control strategy that requires only minor changes in the conventional wind turbine inverter control software to form the AC voltage in the offshore island grid connected via diode rectifier...
This paper introduces a efficient design a the grid side inverter for railway applications in cascaded multilevel hybrid technology. It is shown how to balance the capacitor voltages and how to dimension the capacitor size for different control strategies. Additionally the calculated power losses for this topology are determined and compared with two-level converter.
Reverse-conducting IGBTs (RC-IGBTs) allow the modulation of plasma concentration in diode mode. This can be utilized to put the device in a low saturation mode during conduction in diode direction and to reduce the charge before reverse-recovery. [1] This paper gives an insight into the plasma modulation during the desaturation time and the lock time of RC-IGBTs in diode mode. The influence of these...
Offshore wind farms built at a long distance from the onshore grid are connected via HVDC-transmission. Future HVDC-systems may connect offshore wind farms via uncontrolled diode rectifiers instead of VSC-HVDC converters. Due to this wind turbine inverters must own a grid forming capability. This paper describes a control strategy that requires only minor changes in the conventional wind turbine inverter...
At medium voltage level the three level NPC converter is commonly used. As generator side converter in wind energy applications the diodes are most stressed and limit operation. The BIGT combines the functionality of the IGBT and the free-wheeling diode in one chip. The larger usable chip area in both IGBT and diode mode decreases the maximum junction temperature as well as the junction temperature...
HVDC connected offshore wind farms represent a weak grid that causes stability issues in voltage oriented controlled converters. In addition the conventional line side converter control is not applicable for island grids without an existing AC-voltage source. A Fixed Reference Frame (FixReF) control proved already beneficial in full scale converter wind turbines. In this paper, the usage of FixReF...
The rated power of wind energy plants increases but generators and generator side converters still operate at low voltage level. This leads to high currents and so to large cable cross-sections and high cable losses. The change to medium voltage level overcomes these drawbacks but will make the use of multilevel converters necessary. The Neutral-Point-Clamped three level converter is a common multilevel...
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