Robert A Carroll

US Patent:

40126820, Mar 15, 1977

Filed:

Feb 5, 1975

Appl. No.:

5/547150

Inventors:

Robert J. Carroll - Warren MI
Walter K. O'Neil - Southfield MI

Assignee:

Eaton Corporation - Cleveland OH

International Classification:

H02M 700

US Classification:

321 5

Abstract:

A commutation circuit for an inverter has a capacitor which is charged prior to commutation of the inverter from an auxiliary dc power source instead of by the principal dc power supply for the inverter. Polarity of the voltage on the capacitor is reversed prior to start of commutation by a switch that connects a first inductor across the capacitor to establish a first capacitor current path through the first inductor. No portion of thee first capacitor current by which the capacitor achieves its reverse polarity flows through the inverter. After the polarity of voltage on the capacitor has been reversed the capacitor is connected by switching so as to apply reverse polarity voltage to the dc input busses of the inverter. Commutation current then flows through the inverter, but not through the first inductor. A separate inductor is provided for the commutation current, in series with the capacitor and the inverter.