METHOD OF FREQUENCY CONVERTER CONTROL IN CASE OF POWER SUPPLY INTERRUPTION Russian patent published in 2009 - IPC H02P1/00 H02P27/04 

FIELD: electricity.

SUBSTANCE: when controlling frequency converter with direct current link and voltage inverter with pulse-width modulation (PWM) following steps are to be taken: operating control mode is interrupted, output frequency is saved, output voltage is decreased with limited speed and keeping voltage of the direct current link at the specified level, inverter is blocked, after power supply restoration the inverter is switched on, output voltage is increased and operating control mode is reactivated. Moment of the inverter blocking is defined by counting specified delay time from the moment of the voltage output decrease down to the specified value or from moment of power supply interruption fixation. After power supply restoration output frequency is set equal or proportional to its saved value or according to actual rotation speed of electric motor fed from the converter; output voltage is increased with limited speed keeping at the specified level starting current of the electric motor fed from the converter.

EFFECT: improving starting conditions of electric motor acceleration by frequency converter and reducing losses of rotation speed of driven technological mechanism.

6 cl, 3 dwg