METHOD AND DEVICE FOR CONTROL OF ASYNCHRONOUS MOTOR Russian patent published in 2009 - IPC H02P21/00 H02H7/08 

FIELD: engines and pumps.

SUBSTANCE: invention is related to transforming equipment, namely to control of asynchronous motors. For this purpose in method by set value of asynchronous motor rotation frequency and by accepted law of scalar frequency control of motor, components of vector voltage are generated at the outlet of coordinates converter in fixed double-phase coordinates (Uα, Uβ), according to which generator of pulse-duration modulation (PDM) generates control signals for autonomous voltage inverter, which forms output AC voltage with pulse-duration modulation from DC voltage, then frequency setting variation is stopped in case of input AC voltage variation within broad range or variation of frequency setting, when current or voltage in DC link achieve their critical values, and autonomous voltage inverter is disconnected from source of DC supply until current or voltage in DC link does not become lower than critical value. Device comprises autonomous voltage inverter, three detectors of phase currents, asynchronous motor, DC link, comprising DC detector and parallel connected voltage detector and capacitor, rectifier, source of three-phase AC voltage, charging circuit, block of drivers, driver and control block, comprising interface block, commutation block, setter of intensity, integrator, block of output voltage generation, coordinates converter, PDM generator, block for selection of maximum possible frequency, protection block, charging block, block for setting of fixed phase of voltage vector, block for setting of voltage vector amplitude, amplifier, comparator and frequency metre.

EFFECT: control of asynchronous motor in case of input voltage variation in broad range, start-up of asynchronous motor at run-down without application of rotation frequency detector and efficient braking.

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