SNAPPING CIRCUIT AND MODULATING APPARATUS FOR SEMICONDUCTOR OF POWER TRANSFORTATION

摘要

Power switching elements (1,7 to 6,12) are connected across a D.C. power supply (25) to provide a three-phase voltage output. A snubber circuit is provided as a series arrangement of an asymmetrical voltage element (19 to 24) and a capacitor (13 to 18) connected in parallel with each power switching element (and/or across the D.C. power supply). The unit can be constructed from modules each comprising the semiconductor components (e.g. 1,7,19) to which the capacitor is connected. The module can be hermetically sealed in a synthetic resin moulding shaped to accommodate the capacitor in an overall rectangular parallelepiped shape of the module.