1,764 research outputs found
Thermal Characteristics of Liquid Metal Interconnects for Power Semiconductors
Get PDFDue to its electrical conductivity and fluidity, liquid metal interconnection has the potential to become a new industrial power semiconductors packaging application method to solve the failure of wire bonding liftoff and improve the reliability of power semiconductor applications. As a crucial characteristic in use, the thermal characteristics of liquid metal interconnects for power semiconductors are obtained experimentally in this paper. By powering a diode die in a bridge busbar liquid metal interconnect structure, the thermal resistance from the die to the ambient is extracted. The result shows that the liquid metal interconnects method has the potential to improve the thermal behavior of power semiconductors compared with wire-bonding interconnection. The finite element simulation explains the possible reasons causing abnormal temperature responses among some samples. Besides, during the test, a slow decline in the forward voltage of the module is observed.</p
Multilevel converters for UPS applications: comparison and implementation
No full textIn this paper the possibility to use multilevel converters in UPS applications is discussed. Three different converter topologies, i.e. the three-level diode-clamped, the four-level diode-clamped and the four-level Multi Point Clamped (MPC) have been firstly compared by simulation simulations to find out their efficiency. The Simulink environment has been used, together with Plecs toolbox, to obtain a fast simulation including conduction and switching losses in the components. The MPC turned out to be the converter with the highest efficiency among the three considered and it was implemented to prove the simulation result with some experimental tests. Furthermore, two switching tables for the MPC converter have been implemented and compared in order to minimize the voltage spikes across the switches during the commutations
Power Cycle Test Bench for Accelerated Life Testing of 10 kV SiC MOSFETs
No full textRecent advancement in the area of medium voltage SiC MOSFETs are approaching the maturity level necessary for practical applications and emerging as a potential competitor for Si IGBTs. However since the SiC MOSFET manufacturing process are different from Si production and limited application related experience are available for the reliability of SiC devices. Investigating the defect growth and failure modes in an application relevant environment for SiC are therefore a necessity. A power cycling test-bench for medium voltage has therefore been built to expose SiC Modules to temperature swings during AC operation. The performance of the test-bench is thoroughly verified. The module tested consist of first generation 10 kV SiC MOSFETs and diode dies, packaged at Aalborg University. A detailed infant characterization of the SiC module is performed for post mortem fault behaviour investigation. During power cycling tests the conduction voltages of the SiC dies are measured for monitoring degradation and used as an indicator for state of health
Serial Connection of three phase converters
No full textThis Master thesis deals with the analysis,simulation and implementation of serialconnected converters. The focus is laidon the design of a single phase equivalentcell, comprised of a standard threephase - two level voltage source inverterconnected in series with a bidirectionalfull bridge converter via a high frequencytransformer. In order to realize the highfrequency operation of the transformera modification in the sinusoidal PWMis implemented. Also, several schemesfor commutating the bidirectional fullbridge are analyzed, simulated and tested.Transformer design aim on the minimizationof leakage inductances and for thisreason three prototypes are constructedcompared
Thermoelectric Modeling of IGBT Modules for Transient Operation
No full textIn order to avoid destruction of braking chopper IGBTs, the need of information about instantaneous junction temperature arises. As the operation regime is transient, there is interest of having developed a technique that will allow wind turbine inverter manufacturers to limit the number of paralleled transistors as much as possible, while avoiding physical destruction and keeping the ability of fault ride-through for same period of time. This project proposes a novel electro-thermal model for the braking chopper used in wind turbine converters. The thermal model is realized as a ladder network, for better accuracy. Using thermal information provided by it, the model is developed to emulate dynamic changes in collector-emitter voltage drop. A test setup is proposed in order to reproduce the operating conditions of a braking chopper used in a real field wind turbine application. Electrical devices dimensioning, cooling system design, control and measurement PCBs design are necessary for the setup. The control PCB is designed by taking into consideration that the system must be self-protective. As final purpose, a simple and accurate estimator for junction temperature is realized and presented. The main advantage of the estimator is that it uses only electric measurements – collector current and collector-emitter voltage drop
Mitigation of Common-Mode and Circulating Currents in Power Supplies for Power-to-X Applications
No full textMedium Voltage Modular Multi-Level Inverter
No full textThis project presents the design, building and control of a three phase modular multilevel inverter. The inverter is simulated with respect to the 3 main modulation methods and 3 submodulation methods. The design and the way units are connected are also explained with direct link to their functionality. The inverter topology, a cascaded full H-Bridge inverter allows a multi-level functionality with 9 levels line-to-line and 5 levels line-to-neutral. The modulation strategies are explained for the simulations as well as for the FPGA implementation. The control was simulated using Simulink and Plecs toolboxes inside the Matlab platform. Also FPGA code simulation were carried out. The main aspects of the modulations were expresses the main focus being the simulation and construction of the inverter in order to provide a working platform for either motor control or grid connection
Performance Evaluation of Medium Voltage DC-DC Converters based on 10kV SiC MOSFETS for Energy Storage Systems
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