Showing papers by "Hans Ertl published in 2014"
16 Mar 2014
TL;DR: In this article, an active three-phase rectifier circuit utilizing a Flying Converter Cell (FCC) based on the concept of third harmonic injection was proposed for applications where dc-link voltage control is not required.
Abstract: The proposed active three-phase rectifier circuit utilizing a Flying Converter Cell (FCC) based on the concept of third harmonic injection allows the extension of a passive three-phase diode bridge rectifier to a low-harmonic input stage (THDi <; 5%) for applications where dc-link voltage control is not required. In this work the design and experimental verification of a 10kW laboratory prototype using the proposed concept is addressed. Based on the analysis of the rectifier system a control concept is developed which is implemented in a digital signal processor. It is shown that the proposed rectifier system shows several degrees of freedom which can be used for system optimization. Several implementation details are discussed and experimental results taken from the constructed 10kW laboratory prototype demonstrate the good performance of the proposed rectifier system and verify the proper operation of the developed control concepts.
7 citations
13 Nov 2014
TL;DR: In this article, a voltage balancing concept for an active three-phase rectifier based on the third harmonic injection principle using a flying converter cell (FCC) is proposed, which can advantageously be used for balancing the DC capacitor voltages without disturbing the input currents.
Abstract: In order to reduce input current distortions and improve power factor of a passive three-phase diode bridge rectifier, an active add-on-option circuitry (”Flying Converter Cell”) has been introduced recently. A novel voltage balancing concept for such an active three-phase rectifier which is based on the third harmonic injection principle using a Flying Converter Cell (FCC) is proposed in this paper. It is shown that the midpoint voltage of the FCC can advantageously be used for balancing of the DC capacitor voltages without disturbing the input currents. The proposed balancing concept can simply be added to the existing controller structure consisting of current controllers and a voltage controller. Using the proposed active balancing any losses of alternative passive balancing concepts (resistor networks) can be avoided which maximizes the system’s efficiency. The proposed concept is described in a simple mathematical manner, limitations of the concept are derived and basic operation is verified by simulation results. Measurement results taken from a laboratory prototype with an output power of 10 kW finally demonstrate the good balancing characteristic of the proposed concept.
7 citations
29 Sep 2014
TL;DR: In this article, the authors investigated sources and implications of measurement errors that result for CM/DM separators in a practical measurement environment with a particular focus on the recently presented input impedance criterion.
Abstract: This Paper details two different contributions related to practical CM/DM EMI measurements. A first part investigates sources and implications of measurement errors that result for CM/DM separators in a practical measurement environment with a particular focus on the recently presented input impedance criterion for CM/DM separators. Furthermore, the realization of an active CM/DM separator, which features competitive separation capabilities (DMTR/CMRR > 51 dB and CMTR/DMRR > 47 dB for frequencies up to 10MHz), is presented.
5 citations