Sensorless control system for synchronous motor
AssigneeHitachi, Ltd.
InventorsYoshitaka Iwaji, Tsunehiro Endo, Kiyoshi Sakamoto, Yuhachi Takakura
Life of this patent
Estimating the term…
Abstract
A synchronous motor drive system in accordance with the present invention detects a DC current of an inverter which drives a synchronous motor, and based on the magnitude of the current, estimates torque current components that flow through the motor, and then based on the estimated value, determines the voltage which is applied to the motor, and finally estimates and computes the magnetic pole axis located inside the motor using the estimated value of the torque current.
Claims23
A synchronous motor drive system comprising a synchronous motor, an inverter which applies alternating current to the synchronous motor, direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving a rotation command to said synchronous motor, means for giving current commands Id* and Iq*, Id* on the dc-axis that is assumed to be the magnetic pole axis located inside said synchronous motor and Iq* on the qc-axis that is perpendicular to the dc-axis, and means for computing dc-qc-axis voltage commands based on said current commands Id* and Iq* and said rotation command;
- said synchronous motor drive system sending control signals to said inverter based on the voltage commands for controlling said synchronous motor;
- wherein torque current components inside said synchronous motor are estimated and computed based on the detected current value of said direct current power source, and then said qc-axis component current command Iq* is generated based on the computed value.
A synchronous motor drive system comprising a synchronous motor, an inverter which applies alternating current to the synchronous motor, a direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving a rotation command to said synchronous motor, means for computing an alternating current phase of said synchronous motor based on the rotation command, and means for computing voltage commands applied to said synchronous motor;
- wherein:
- said synchronous motor drive system sends control signals to said inverter based on the voltage commands for controlling said motor;
- a corrected current value is formed by performing a differential or partial differential correction to a detected current value of said direct current power source;
- and
- said alternating current phase is corrected using the corrected current value.
A synchronous motor drive system comprising a synchronous motor, an inverter which applies alternating current to the synchronous motor, a direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving a rotation command to said synchronous motor, means for giving current commands Id* and Iq*, Id* on the dc-axis that is assumed to be the magnetic pole axis (d-axis) located inside said synchronous motor and Iq* on the qc-axis that is perpendicular to the dc-axis, and means for computing said dc-qc-axis voltage commands based on the current commands Id* and Iq* said rotation command;
- said synchronous motor drive system sending control signals to said inverter based on the voltage commands for controlling said synchronous motor;
- said synchronous motor drive system further comprising means for estimating and computing a torque current component which is perpendicular to the magnetic pole axis located inside said synchronous motor, based on the detected current value of said direct current power source, means for computing the error Δθ between said d-axis and said dc-axis using the estimated value of said torque current component, and means for generating said current command Iq* based on the error Δθ.
A synchronous motor drive system a synchronous motor, an inverter which applies alternating current to the synchronous motor, a direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving a rotation command to said synchronous motor, means for computing an alternating current phase of said synchronous motor based on the rotation command, means for giving current commands Id* and Iq*, Id* on the dc-axis that is assumed to be the magnetic pole axis (d-axis) located inside said synchronous motor and Iq* on the qc-axis that is perpendicular to the dc-axis, and means for computing said dc-qc-axis voltage commands based on the current commands and said rotation command;
- said synchronous motor drive system sending control signals to said inverter based on the voltage commands for controlling said synchronous motor;
- said synchronous motor drive system further means for estimating and computing a torque current component which is perpendicular to the magnetic pole axis located inside said synchronous motor, based on the detected current value of said direct current power source, means for computing the error Δθ between said d-axis and said dc-axis using the estimated value of said torque current component and correcting said alternating current phase based on the obtained error Δθ, and means for generating a current command Iq* based on an adjusted amount for correcting said alternating current phase.
A synchronous motor drive system comprising a synchronous motor, an inverter which applies alternating current to the synchronous motor, a direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving a rotation command to said synchronous motor, means for giving current commands Id* and Iq*, Id* on the dc-axis that is assumed to be the magnetic pole axis (d-axis) located inside said synchronous motor and Iq* on the qc-axis that is perpendicular to the dc-axis, and means for computing said dc-qc-axis voltage commands based on the current commands and said rotation command;
- said synchronous motor drive system sending control signals to said inverter based on the voltage commands for controlling said synchronous motor;
- said synchronous motor drive system further comprising means for estimating and computing a torque current component which is perpendicular to the magnetic pole axis located inside said synchronous motor, based on the detected current value of said direct current power source, means for computing the error Δθ between said d-axis and said dc-axis using the estimated value Iqc of said torque current component and estimating rotation of said synchronous motor based on the obtained error Δθ, means for computing an alternating current phase of said synchronous motor based on the estimated value of said rotation, and means for generating a current command Iq* based on the deviation between said rotation command and the estimated value of said rotation.
A synchronous motor drive system comp sing a synchronous motor, an inverter which applies alternating current to the synchronous motor, a direct current power source which supplies power to the inverter, means for detecting a current supplied from the direct current power source to said inverter, means for giving rotation command to said synchronous motor, means for giving a torque command to said synchronous motor, and means for computing voltage commands of said synchronous motor based on said torque command and said rotation command;
- said synchronous motor drive system sending control signals to said inverter based on the voltage commands for controlling said synchronous motor;
- wherein torque occurring inside said synchronous motor is computed using the detected current value of said direct current power source and then said torque command is generated based on the computed value Tmc.
Dependencies are inferred from the claim text.