VARIABLE-FREQUENCY CONTROL DEVICE OF ASYNCHRONOUS ELECTRIC MOTOR Russian patent published in 2011 - IPC H02P23/00 

FIELD: electricity.

SUBSTANCE: variable-frequency control device includes asynchronous motor, frequency and voltage converter the control inputs of which are connected to outputs of the second and the third adders, the first input of the second adder is connected to functional transducer, the first input of the third adder is connected to the output of the first adder the first input of which is connected to signal setting source, current sensors of stator winding of motor, the outputs of which are connected to the first and the second inputs of functional current transducer the second output of which is connected to the second reversible input of the fourth adder, the first input of which is connected to current limiting signal source, and output of the fourth adder is connected to the input of the second static non-linear transducer the output of which is connected to the input of proportional integral control. The first output of functional current transducer is connected to input of static transducer and to input of the first static non-linear transducer, the outputs of which are connected to the second inputs of the second and third adders respectively. Output of proportional integral control is connected to the second input of the first adder.

EFFECT: providing overload capacity of drive, reducing losses in stator and rotor of motor which is under high loads owing to decreasing the slide and increasing the flow.

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