Per-phase output current control of 4-leg active power filter based on adaptive notch filter. - In: 2022 IEEE 23rd International Conference of Young Professionals in Electron Devices and Materials, (2022), S. 388-393
This paper presents control strategy of four-leg four-wire active power filter for independent phase current control. The strategy is based on digital notch filter adaptive to grid voltage frequency to maintain high quality compensation under grid voltage frequency variations inherent in microgrids with distributed generation and standalone power supply systems using fast response phase-locked loop system. Proposed control strategy requires no coordinate transformation and operates directly with load and converter currents which significantly reduces computational load and dynamic phase interaction. Mathematical modeling of the converter with LC filter and neutral wire inductor was carried out and mathematical equations were obtained to choose the parameters of the current controller (proportional and integral gains) based on the desired bandwidth of the current control loop, power stage reactive elements nominal values, and DC-side nominal voltage level. Proposed control strategy was studied using Matlab/Simulink simulation under distorted grid with variable frequency, and experimental verification using laboratory prototype of the system was implemented.
https://doi.org/10.1109/EDM55285.2022.9855148
MMC stationary operating regimes in case of periodic power demand on the DC side. - In: IEEE transactions on power electronics, ISSN 1941-0107, Bd. 37 (2022), 7, S. 7640-7651
The operation of modular multilevel converters (MMCs) with a periodic dc-side voltage is considered whose fundamental frequency component is linked to the grid frequency. Such a voltage component arises for instance by operating a pulsed power load, which is analyzed in this article as an example for this problem class. This application entails harmonic voltage components, which in conjunction with the ac current, lead to an imbalance of the available arm voltages. Although purely feedback-based balancing schemes can reduce the imbalance, they may fail to mitigate it sufficiently. Considering the balancing problem already during the stationary regime design, new options appear, which are to be investigated. Recent modeling methods are employed in order to analyze and mitigate this imbalance. In particular, the imbalance is already dealt with during the determination of suitable stationary operating regimes. Thanks to this, four regimes are derived, one of which is analogous to an already published regime for the concerned application. The regimes are compared on the basis of their individual advantages and their impact on the converter rating. Three of them avoid the singularity that is present in the already published regime. The findings are supported by numerical and experimental results.
https://doi.org/10.1109/TPEL.2022.3143318
Sliding-mode control for interleaved operation of parallel-connected three-phase active front-ends. - In: IEEE journal of emerging and selected topics in power electronics, ISSN 2168-6785, Bd. 10 (2022), 6, S. 6545-6556
A converter system is considered that consists of parallel-connected two-level voltage source converters that share the same ac and dc terminals. A controller design is proposed that, in a first stage, controls the grid currents using hysteresis controllers. To this end, augmented grid currents are introduced that feature a decoupling between the phases. As a consequence, a switching action in one phase does not affect the derivatives of these currents in the other phases. In a second stage, the converter currents are controlled using hysteresis controllers such that a desired current distribution among the parallel converters may be ensured. This implicitly sets the circulating currents. The proposed approach is verified by measurements on an industrial MW-scale testbench with ten parallel converters. The results are compared with a benchmark approach, with the proposed approach showing lower semiconductor losses and grid current harmonic distortion.
https://doi.org/10.1109/JESTPE.2021.3113937
EMI filter for a three-phase 800 kHz nine-level flying capacitor GaN multilevel inverter. - In: 2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe), (2021), S. P.1-P.10
This paper presents a Gallium Nitride (GaN) three-phase nine-level flying capacitor multilevel inverter with a switching frequency of 800 kHz and a peak efficiency above 99 %. The focus is on the noise spectrum and the EMI filter layout for the differential mode (DM) and the common mode noise (CM). Special attention is given to an analysis of different parasitic components and their effect on the resulting EMI spectrum.
https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570600
The investigation of a hybrid cascaded multilevel matrix converter. - In: 2021 IEEE 22nd International Conference of Young Professionals in Electron Devices and Materials (EDM), (2021), S. 360-364
https://doi.org/10.1109/EDM52169.2021.9507718
Energy-balancing of a Modular Multilevel Converter with pulsed DC load using an online trajectory planning algorithm. - In: 2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe), (2021), S. P.1-P.10
Modular Multilevel Converter (MMC) energy balancing is a nontrivial open-loop control problem since the choice of a technically meaningful output leads to an internal dynamics. A large voltage ripple on the dc side of an MMC may cause permanent arm power imbalances. For example, the large voltage ripple at the smoothing capacitor of a pulsed dc load can affect the supplying MMC. This paper focuses on the energy balancing task of MMCs supplying the smoothing capacitor of a pulsed dc load. The approach introduced in this paper is to define feasible stationary operating regimes with circulating current injection and plan appropriate trajectories solved analytically for all variables. This lends itself to an online implementation and provides a feedforward energy control supporting the standard feedback based energy balancing. Test bench measurements confirm improved energy control performance compared to standard feedback balancing.
https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570671
Ethernet-basierte Ultra-Hochgeschwindigkeitskommunikation für eine Regelung dezentraler Einspeiseumrichter von Windenergieanlagen. - In: Kommunikation in der Automation (KommA 2021), (2021), insges. 8 S.
Tagung: KommA 2021, 18.11.2021 in Magdeburg
In diesem Beitrag wird eine Ethernet-Ultra-Hochgeschwindigkeitskommunikation vorgestellt, welche auf der Nutzung von GBit-Ethernet-PHYs in Verbindung mit einer FPGA-Protokollverarbeitung basiert. Hierzu wurde ein mit IEEE 802-Standards kompatibles Protokoll entwickelt, welches es dem Empfänger ermöglicht, Daten bereits vor dem vollständigen Empfang eines Paketes zu nutzen. Die Protokollverarbeitung wurde vollständig in Hardware umgesetzt, welche alle Verarbeitungsschritte zwischen der GBit-Schnittstelle des PHYs und der systeminternen Datenschnittstelle vornimmt. Im Rahmen einer Fallstudie wurde ein FPGA-basierter Systemaufbau zur quantitativen Ermittlung der Kommunikationseigenschaften umgesetzt. In jedem Zyklus sendet dabei eine Zentralsteuerung Echtzeitdaten zur Ansteuerung von IGBT-Umrichter-Brücken und empfängt jeweils Strommesswerte. Für die in der Anwendung relevanten Mengen an zu übertragenden Echtzeitdaten wurden an dem Aufbau Endezu- Ende-Latenzen in der Größenordnung < 1 μs sowie ein Jitter < 50 ns gemessen. Aufgrund der Protokollverarbeitung repräsentieren diese Werte die Kommunikationseigenschaften zwischen den späteren Applikationen, welche in der Steuerung und den verteilten IGBT-Umrichterbrücken ausgeführt werden.
https://opendata.uni-halle.de//handle/1981185920/41549
Analyzing and optimizing the switching behavior of power electronics by automated PCB parasitics extraction of the critical path. - In: 2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe), (2021), S. P.1-P.8
This paper presents an algorithm to support the PCB design process by automatically extracting its parasitic components in the critical path from a common EDA tool. An algorithm reads the board file from an EDA tool and feeds the information to the open source programs FastHenry2 and FasterCap. These programs are used for the extraction of frequency-dependent resistances, self and mutual inductances of the PCB tracks as well as the capacitances between those tracks. By augmenting the extraction process by automatically finding the critical path in any given power converter, the extraction procedure can be sped-up significantly and made more user-friendly. Especially in fast-switching applications this approach helps to reduce the usually needed design iterations by knowing the effect of differently routed PCBs. The accuracy of the calculated parasitics is verified by experimental results.
https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570455
Analysis and implementation of a novel four-step commutation method for direct matrix converters based on FPGA and DSP. - In: 2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe), (2021), S. P.1-P.9
This paper presents a novel current-controlled four-step commutation method for robust and safe operation of direct matrix converters (DMC) by dynamically adjusting the most critical commutation time according to amplitude of the output load current, which is an optimization for the overall necessary commutation time. Meanwhile, this method also helps to ensure the desired switching sequence to be implemented correctly. The principle of proposed strategy is explained in detail and a formula of setting the most critical commutation time is given. Simulation results are used to verify this proposed strategy. A low voltage laboratory platform consisting of a DMC and a brushless motor (BLDC) is implemented and controlled using a hybrid hardware concept based on a field-programmable gate array (FPGA) and a digital signal processor (DSP). Experimental studies on the laboratory prototype confirm the feasibility and effectiveness of the proposed method.
https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570664
Solid state transformer as a part electrical circuit for data center application. - In: 2021 IEEE 22nd International Conference of Young Professionals in Electron Devices and Materials (EDM), (2021), S. 354-359
https://doi.org/10.1109/EDM52169.2021.9507640