| 1. |
- Domeij, Martin, et al.
(författare)
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SiC power bipolar junction transistors : Modeling and improvement of the current gain
- 2005
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Ingår i: 2005 European Conference on Power Electronics and Applications. - Dresden : IEEE. - 9075815085 - 9789075815085 ; , s. 1665888-
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Konferensbidrag (refereegranskat)abstract
- Epitaxial silicon carbide bipolar junction transistors (BJTs) for power switching applications have been designed and fabricated with a maximum breakdown voltage of 1100 V. The BJTs have high common emitter current gains with maximum values exceeding 60, a result that is attributed to design optimization of the base and emitter layers and to a high material quality obtained by a continuous epitaxial growth. Device simulations of the current gain as function of collector current have been compared with measurements. The measurements show a clear emitter-size effect that is in good agreement with simulations including surface recombination in interface states at the etched termination of the base-emitter junction. Simulations indicate an optimum emitter doping around 1-1019 cm-3 in agreement with typical state-of-the-art BJTs.
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| 2. |
- Hansson, Jörgen, et al.
(författare)
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Minimizing power pulsations in a free piston energy converter
- 2005
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Ingår i: 2005 European Conference on Power Electronics and Applications. - 9789075815085
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Konferensbidrag (refereegranskat)abstract
- A Free Piston Energy Converter (FPEC) is a combination of a linear combustion engine and a linear electrical machine. This type of converter has many potential advantages like high efficiency, low fuel consumption and low emissions, which make it suitable for a series hybrid vehicle. However, the generated power pulsates due to the reciprocating motion of the translator. This paper presents a comparative study on how different generator force profiles affect the electric power pulsations produced by the FPEC. In addition, the influence of these profiles on translator motion and the needed power converter current is investigated. A dynamic free piston model is used for the investigation. Results show that the generator force profile has a major impact on the power pulsation amplitude and peak current demand. Thus the chosen force profile will affect dimensioning of power converter, electrical machine and energy storage. Furthermore, loading the translator heavily in the beginning or end of the stroke seems to affect the peak translator velocity more than evenly distributed load profiles.
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| 3. |
- Ranstad, Per, et al.
(författare)
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A novel control strategy applied to the series loaded resonant converter
- 2005
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Ingår i: 2005 European Conference on Power Electronics and Applications. - Dresden : IEEE. - 9789075815085 ; , s. 1665918-
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Konferensbidrag (refereegranskat)abstract
- An novel control strategy of the series loaded resonant converter is presented. The main objective of the control strategy is to minimize the switching losses in the main switching elements (IGBT). The results are experimentally verified on a 60kW/25kHz prototype converter. The IGBT losses obtained with the proposed control strategy are compared with those of the commonly used frequency control and phase-shift control strategies. With the proposed control strategy it is found that the losses are reduced in the entire operating range compared to phase-shift control. The same statement is valid also for frequency control, except for the highest output voltage.
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| 4. |
- Wallmark, Oskar, 1976, et al.
(författare)
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Post-fault operation of fault-tolerant inverters for PMSM drives
- 2005
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Ingår i: European Conference on Power Electronics and Applications. - 9075815085 - 9789075815085
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Konferensbidrag (refereegranskat)abstract
- This paper considers post-fault operation of permanent-magnet synchronous motor drives equipped with a fault-tolerant inverter. In post-fault mode, the faulted phase is isolated and the neutral point is connected either to an additional inverter leg or to the midpoint of the dc bus. Different methods of controlling the neutral point voltage are presented and compared. Furthermore, operation without a position sensor (i.e., sensorless control) is considered and a modification to an estimator previously reported in the literature is proposed in order to take into account the effect of the asymmetry introduced due to the isolation of the faulted phase in post-fault mode. Simulations and experimental results are provided to support the theory and demonstrate the practical impact of the modifications proposed.
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