Control apparatus of induction motor

A control apparatus of an induction motor, comprising:

• a detector for detecting a primary current of the induction motor;
• primary current component detecting means for detecting an exciting current and a torque current from the current detected by the detector;
• correcting means for outputting a correction voltage to set to zero a difference between an exciting current command value and the exciting current outputted from the primary current detecting means;
• frequency-voltage control means for outputting a frequency command and a voltage command based on
• an output of the correcting means,
• a primary resistance of the induction motor,
• a leakage inductance of the induction motor, and
• an inductance ratio of the induction motor, the inductance ratio being a ratio of a mutual inductance of the induction motor to a secondary self-inductance of the induction motor;
• and
• at least one constant correcting means selected from a first constant correcting means, a second constant correcting means, and a third constant correcting means,
• the first constant correcting means being for correcting the primary resistance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the primary resistance,
• the second constant correcting means being for correcting the leakage inductance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the leakage inductance, and
• the third constant correcting means being for correcting the inductance ratio based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the inductance ratio.

A control apparatus of an induction motor, comprising:

• a detector for detecting a primary current of the induction motor;
• primary current component detecting means for detecting an exciting current and a torque current from the current detected by the detector;
• correcting means for outputting a correction voltage to set to zero a difference between an exciting current command value and the exciting current outputted from the primary current detecting means;
• frequency-voltage control means for outputting a frequency command and a voltage command based on
• an output of the correcting means,
• a primary resistance of the induction motor,
• a leakage inductance of the induction motor, and
• an inductance ratio of the induction motor, the inductance ratio being a ratio of a mutual inductance of the induction motor to a secondary self-inductance of the induction motor;
• and
• at least one constant correcting means selected from a first constant correcting means, a second constant correcting means, and a third constant correcting means,
• the first constant correcting means being for correcting the primary resistance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the primary resistance,
• the second constant correcting means being for correcting the leakage inductance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the leakage inductance, and
• the third constant correcting means being for correcting the inductance ratio based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the inductance ratio;
• wherein the frequency-voltage control means outputs a frequency command and a voltage command based on a constant obtained by an arithmetic operation from
• the primary resistance,
• the inductance ratio,
• the leakage inductance, and
• a preset value;
• and
• wherein the second constant correcting means corrects the constant based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the constant.

A control apparatus of an induction motor, comprising:

• a detector for detecting a primary current of the induction motor;
• primary current component detecting means for detecting an exciting current and a torque current from the current detected by the detector;
• correcting means for outputting a correction voltage to set to zero a difference between an exciting current command value and the exciting current outputted from the primary current detecting means;
• frequency-voltage control means for outputting a frequency command and a voltage command based on
• an output of the correcting means,
• a primary resistance of the induction motor,
• a leakage inductance of the induction motor, and
• a primary self-inductance of the induction motor;
• and
• at least one constant correcting means selected from a first constant correcting means, a second constant correcting means, and a third constant correcting means,
• the first constant correcting means being for correcting the primary resistance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the primary resistance,
• the second constant correcting means being for correcting the leakage inductance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the leakage inductance, and
• the third constant correcting means being for correcting the primary self-inductance based on a quantity obtained by multiplying a quantity of the voltage command outputted from the frequency-voltage control means by the output of the correcting means, the quantity of the voltage command being a result of partial differentiation with the primary self-inductance.

A control apparatus of an induction motor, comprising:

• a detector for detecting a primary current of the induction motor;
• primary current component detecting means for detecting an exciting current and a torque current from the current detected by the detector;
• correcting means for outputting a correction voltage to set to zero a difference between an exciting current command value and the exciting current outputted from the primary current detecting means;
• frequency-voltage control means for outputting a frequency command and a voltage command based at least on one of
• (1) an output of the correcting means, a primary resistance of the induction motor, a leakage inductance of the induction motor, and an inductance ratio of the induction motor, the induction ratio being a ratio of a mutual inductance of the induction motor to a secondary self-inductance of the induction motor, and
• (2) a constant replacing at least one of the primary resistance, the leakage inductance, and the inductance ratio, the constant being obtained by a calculation from the primary resistance, the leakage inductance, the inductance ratio, and a preset value;
• and
• constant correcting means for correcting the constant for use in the frequency-voltage control means to set to zero the correction voltage output by the correcting means.