Loss Model for Gallium Nitride DC-DC Buck Converter
This work was supported primarily by the Engineering Research Center Program of the National Science Foundation and the Department of Energy under NSF Award Number EEC- 1041877 and the CURENT Industry Partnership Program.
Loss modeling for enhancement mode gallium nitride field efect transistor in power converter applications
Wide bandgap devices have been drawn significant research interests for future renewable energy applications thanks to the advantages of high switching performance, high achievable junction temperature, and low on-resistance in comparison with silicon-based devices. It becomes more and more important to understand the switching characteristics for designing high-efficient power converters. A model for estimating switching power losses in enhancement mode gallium nitride (eGaN) Field effect transistor (FET) is developed and presented in this paper. The loss modeling considers both the on resistance and parasitic capacitances that arise from inherent manufacturing processes. A 12V/24V boost converter is prototyped by using eGaN FET and used to validate the proposed model by comparing the experimental result with simulation. The switching losses are calculated for different frequencies and compared with experimental result and show a strong correlation with the expectation in simulations. It shows that the loss model inaccuracy is less than 10%.
Ideological Quietism? Ideology and Party Politics in Britain
Ideology and political parties are frequently depicted as disparate entities, with scholars citing a range of exogenous and endogenous changes to demonstrate the decreasing relevance of ideology to party politics. This article moves away from such accounts by looking at the role of actors, and specifically party leaders, in contributing to perceptions of ideological decline. Through an examination of the rhetoric of Labour and Conservative Party leaders in Britain between 1946 and 1997, this article contends that politicians have engaged in, what is termed here, ‘ideological quietism’. In this sense, parties have not abandoned ideology but have made rhetorical shifts indicative of ideological decline.