Design and Implementation of Grid-Connected Power Converter for PEM Fuel Cells
| Autor: | Ying-Jie Liao, 廖英傑 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 This thesis presents a power converter for proton exchange membrane fuel cell (PEMFC). The proposed converter is composed of consists a push-pull converter and a grid-connected inverter. The push-pull converter is controlled by the KA3525 IC, which changes the power transistor duty cycle to adjust the output voltage level. Subsequently the low voltage DC electricity is converted into the high voltage DC electricity. The converter is suitable for system with a low input voltage and large input current as powered by PEMFC. The proposed grid-connected inverter converts DC power of push-pull converter into AC power and connects to the utility system. The grid-connected inverter has the functions of frequency protection, over current protection, and islanding protection. The proposed islanding protection contains passive islanding detection method and active islanding detection method. The passive islanding detection method is based on two indices: the rate of change of frequency (ROCOF) and the rate of change of voltage (ROCOV). When the inverter is grid-interconnected, the ROCOF and ROCOV are lower than the threshold value. In contrast, as an islanding occurs, the ROCOF or ROCOV become much higher than the threshold values. The proposed the active islanding detection method is based on active frequency drift. To demonstrate the effectiveness of the proposed power converter, an 110V, 300W, prototype power converter has been tested under several load conditions. The test results show that the proposed power converter is efficient and reliable. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|