摘要 |
An equalizer circuit for switches connected in series between a voltage source (21) and a load (16), each switch (4, 11) being connected in parallel with a respective equalizing capacitor (2, 9) via a respective diode (7, 8). The circuit further includes a transformer (20) having a plurality of windings (6, 13) connected in series with respective diodes (5, 12), with each switch having a respective winding-diode series connection connected in parallel therewith. In this manner, electrical energy initially stored in the capacitors is transferred to be stored in magnetic form by the windings when the switches are closed and is re-used when the switches are opened to accelerate charging of the less charged capacitors until all the capacitors reach the voltage of the most charged capacitor. The invention is particularly applicable to semiconductor switches such as transistors or gate turnoff thyristors connected in series and needing protection against exposure to excessive voltages due to differences in switching times between switches.
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