Patent ID: 8937451
Filing Date: 2015-01-20
Classification: H02M,H02P

Abstract:
1. A motor control apparatus comprising: a smoothing capacitor coupled to a source of a DC voltage, to provide a smoothed DC voltage between opposing terminals of said smoothing capacitor; a control circuit, and a plurality of DC-to-AC inverter circuits connected to respectively corresponding ones of a plurality of electric motors, each of said DC-to-AC inverter circuits comprising a plurality of switching circuits respectively controlled by said control circuit, all of said switching circuits being connected in parallel between said opposing terminals of said smoothing capacitor, each of said switching circuits comprising a pair of switching elements connected in series, with a junction of each of said pairs of switching elements of a DC-to-AC inverter circuit being connected to said corresponding electric motor, each of said switching circuits controlled by said control circuit for converting said smoothed DC voltage to an AC voltage and supplying said AC voltage to said corresponding electric motor; said control circuit responding to removal of said DC voltage source by setting both of respective switching elements of a switching circuit in a conducting condition, for discharging a residual charge of said smoothing capacitor; wherein said control circuit is configured to respond to said removal of the DC voltage source by setting both of respective switching elements of a single switching circuit of each of said plurality of DC-to-AC inverter circuits in a conducting condition, for discharging said residual charge, while setting all other switching elements of said switching circuits in a non-conducting condition.