Showing papers by "Hans Ertl published in 2016"
10 May 2016
TL;DR: The paper presents a comparison of estimated and measured semiconductor losses for discrete as well as module packaging and discusses the implementation of the gate driver stage, of the DC link and of the EMI output filter.
Abstract: The paper reports design and performance evaluation of a three-phase AC power source which is mainly used for the development, validation and testing of grid connected converter system and components. The main objective of the designed AC power source is the controllability of the output (grid) voltage amplitude and frequency, harmonic components as well as of the grid impedance characteristic. The small signal bandwidth of the proposed system is specified up to 2 kHz. To fulfill this requirement at very low output noise voltage levels, the target switching frequency has to be in the region of 200 kHz. For achieving acceptable efficiency 1200V silicon carbide (SiC) MOSFETs are used. The paper presents a comparison of estimated and measured semiconductor losses for discrete as well as module packaging and discusses the implementation of the gate driver stage, of the DC link and of the EMI output filter.
4 citations
TL;DR: In this paper, an active add-on option for 208 VLL/60 Hz passive three-phase rectifiers is presented, which is implemented as a center-tapped full-bridge stage and guarantees lowharmonic input currents and unity power factor.
Abstract: An active add-on option for 208 VLL/60 Hz passive three-phase rectifiers is presented. The active optional circuit is implemented as ‘centre-tapped’ full-bridge stage and guarantees low-harmonic input currents and unity power factor. The active unit is able to operate for a wide frequency range and therefore applicable for high- (e.g. >100 kW) and low-power applications. Some basic considerations such as principle operation, duty cycles, voltage/current stress of switches and design of inductors are discussed and additionally supported by simulation results. Applicability of emerging wide bandgap power devices such as silicon carbide MOSFETs, which improve converter efficiency and power density, is furthermore briefly discussed.
2 citations
20 Mar 2016
TL;DR: Experimental results of a laboratory prototype based on a 10 kW/72 kHz rectifier system using SiC-MOSFETs verifies the proper behaviour of the proposed upgrade and various implementation issues are discussed.
Abstract: A recently proposed third harmonic injection rectifier (two half-bridge legs) - serving as optional solution for passive three-phase diode bridge systems with LC output filter - is characterized by unity power factor (λ ≈ 1) and low harmonic input currents (THD < 5%). The rectifier at hand, furthermore sticks out of the crowd due to a very low number of active and passive switches compared to similar power electronic circuits based on the same (third harmonic injection) principle. Additionally, the more and more establishing and reliable SiC-MOSFET allows an optimized design for higher switching frequencies without seriously impairing the efficiency of the total system. A proper design of active and passive components of the optional circuit is therefore required and several operating modes and optimization possibilities are existing. Besides basic considerations of control structures and topology limitations, also various implementation issues are discussed. Finally, experimental results of a laboratory prototype based on a 10 kW/72 kHz rectifier system using SiC-MOSFETs verifies the proper behaviour of the proposed upgrade.
1 citations