Vector controller for permanent-magnet synchronous electric motor
First Claim
1. A vector controller for a permanent-magnet synchronous electric motor that controls an alternating current from an inverter that drives the permanent-magnet synchronous electric motor so as to come into coincidence with a current command, comprising:
- a reference phase-angle calculation unit for generating a reference phase angle of the permanent-magnet synchronous electric motor;
a current command generation unit for generating the current command using a given torque command;
a current control unit for making a control calculation of a current error between the current command and a current through the permanent-magnet synchronous electric motor, to output the calculated current error;
a decoupling voltage calculation unit for calculating a feed-forward voltage using motor parameters of the permanent-magnet synchronous electric motor and the current command;
a modulation index calculation unit for outputting a modulation index for the inverter by receiving a direct-current voltage to the inverter and a voltage command that is the sum of the current error and the feed-forward voltage;
a control phase-angle calculation unit for outputting a control phase angle for the inverter by receiving the voltage command and the reference phase angle;
a pulse-width-modulation signal generation unit for generating pulse-width-modulation signals for the inverter using the modulation index and the control phase angle; and
a current command compensator for correcting the current command using a corrected current command calculated based on the modulation index;
whereinthe current command compensator sets the corrected current command to a value obtained by processing through a time delay element and by multiplying by a predetermined constant the difference between the modulation index and a predetermined modulation index set value.
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Abstract
A method of controlling a current command by comparing voltage with a set value needs to vary the set value depending on voltage fluctuation, which involves taking a complicated control. A vector controller for a permanent-magnet synchronous electric motor, according to the present invention, can realize with a simplified configuration a field-weakening operation in a one-pulse mode in a high speed range by providing a current command compensator that corrects a current command by a corrected current command calculated based on a modulation index.
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Citations
16 Claims
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1. A vector controller for a permanent-magnet synchronous electric motor that controls an alternating current from an inverter that drives the permanent-magnet synchronous electric motor so as to come into coincidence with a current command, comprising:
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a reference phase-angle calculation unit for generating a reference phase angle of the permanent-magnet synchronous electric motor; a current command generation unit for generating the current command using a given torque command; a current control unit for making a control calculation of a current error between the current command and a current through the permanent-magnet synchronous electric motor, to output the calculated current error; a decoupling voltage calculation unit for calculating a feed-forward voltage using motor parameters of the permanent-magnet synchronous electric motor and the current command; a modulation index calculation unit for outputting a modulation index for the inverter by receiving a direct-current voltage to the inverter and a voltage command that is the sum of the current error and the feed-forward voltage; a control phase-angle calculation unit for outputting a control phase angle for the inverter by receiving the voltage command and the reference phase angle; a pulse-width-modulation signal generation unit for generating pulse-width-modulation signals for the inverter using the modulation index and the control phase angle; and a current command compensator for correcting the current command using a corrected current command calculated based on the modulation index;
whereinthe current command compensator sets the corrected current command to a value obtained by processing through a time delay element and by multiplying by a predetermined constant the difference between the modulation index and a predetermined modulation index set value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification