Marcin Hołub, Stanisław Kalisiak and Krzysztof Ruchała
The purpose of this paper is to introduce a unique multilevel, one‐phase inverter (in the multiplied full‐bridge configuration, cascaded‐type) with unequal voltage distribution…
Abstract
Purpose
The purpose of this paper is to introduce a unique multilevel, one‐phase inverter (in the multiplied full‐bridge configuration, cascaded‐type) with unequal voltage distribution among the voltage levels.
Design/methodology/approach
Numerical and experimental results are discussed and the topology thereafter evaluated.
Findings
Unequal voltage distribution among voltage stages of the converter leads to increase of the output voltage resolution while simplifying the converter construction and minimizing the power switch losses. Simplorer numerical analyses as well as test stand measurements were led in order to verify properties of the system. Using the voltage distribution in the proportion of 6/2/1 leads to improved utilisation of power switches used in the means of voltage, current and switching frequency. FFT analysis was implemented in order to explore the frequency domain properties of the control apparatus.
Practical implications
The results allow improvement of power switch utilisation and output voltage resolution of cascaded, three‐stage multilevel converter topologies and voltage output filter optimisation for multilevel power electronic converters.
Originality/value
A new concept of voltage distribution is provided and described, a dedicated DSP‐based control system was developed as well as a small‐scale converter prototype, test stand measurement results are provided.
Details
Keywords
Cezary Galinski, Grzegorz Krysztofiak, Marek Miller, Pawel Ruchala, Marek Kalski, Mateusz Lis, Adam Dziubinski, Krzysztof Bogdanski, Lukasz Stefanek and Jaroslaw Hajduk
The purpose of this paper is to present the methodology and approach adapted to conduct a wind tunnel experiment on the inverted joined-wing airplane flying model together with…
Abstract
Purpose
The purpose of this paper is to present the methodology and approach adapted to conduct a wind tunnel experiment on the inverted joined-wing airplane flying model together with the results obtained.
Design/methodology/approach
General assumptions underlying the dual-use model design are presented in this paper. The model was supposed to be used for both wind tunnel tests and flight tests that significantly drive its size and internal structure. Wind tunnel tests results compared with the outcome of computational fluid dynamics (CFD) were used to assess airplane flying qualities before the maiden flight was performed.
Findings
Extensive data about the aerodynamic characteristics of the airplane were collected. Clean configurations in symmetric and asymmetric cases and also configurations with various control surface deflections were tested.
Practical implications
The data obtained experimentally made it possible to predict the performance and stability properties of the unconventional airplane and to draw conclusions on improvements in further designs of this configuration.
Originality/value
The airplane described in this paper differs from frequently analyzed joined-wing configurations, as it boasts a front lifting surface attached at the top of the fuselage, whereas the aft one is attached at the bottom. The testing technique involving the application of a dual-use model is also innovative.