ELECTRIC-DRIVE POWER CIRCUIT INCORPORATING SMOOTHING REACTOR IN DC CIRCUIT Russian patent published in 2004 - IPC

FIELD: electrical engineering; variable speed induction-motor drives coupled with final elements of mechanotronic systems such as manipulators, numeric-control machines. SUBSTANCE: electric-drive power circuit incorporating smoothing reactor in dc circuit has uncontrolled rectifier connected to ac power supply and through smoothing reactor, to dc motor armature winding, the latter being connected through transistor switch to minus bus of uncontrolled rectifier; center tap of smoothing reactor winding is connected to LC filter capacitor and to reset diode cathode. Novelty is that electric drive power circuit is provided in addition with current sensor, zero current comparator, control pulse shaper, two transistor switches, two isolating diodes, metering capacitor, two switching components, and control unit. Smoothing reactor has additional winding; starting lead of reactor primary winding is connected through first switching component to current sensor whose output is connected to motor armature winding, to second switching component, and through low-voltage output of current sensor, to input of zero-current comparator whose output is connected to first input of control pulse shaper; output of the latter is connected to base of second transistor switch. First switching component is connected through emitter-collector junction of third transistor switch to first isolating diode whose cathode is connected to positive plate of metering capacitor, to cathode of second isolating diode, and to starting lead of smoothing reactor secondary winding; finishing lead of the latter is connected through emitter-collector junction of second transistor switch to negative plate of metering capacitor and to dc motor armature. Second switching component is connected through variable resistor to dc motor armature and to emitter of first transistor switch. Control unit is connected to bases of first and third transistor switches and to second input of control pulse shaper. EFFECT: reduced power loss in dc motor at low drive speeds; reduced mass of smoothing reactor magnetic circuit. 1 cl, 5 dwg