Method for measuring characteristic constants of alternating current motor and controller thereof based on said method
First Claim
1. A method of measuring characteristic constants of a three-phase alternating current motor controlled by an inverter apparatus including a three-phase inverter for converting a direct current voltage into a three-phase alternating current so as to supply the three-phase alternating current to said three-phase motor and a controller for controlling the magnitude and pulse-width of an output voltage of said three-phase inverter, the method comprising the steps of:
- producing single-phase alternating current excitation signals based on a primary frequency command value ω
1 and a primary voltage command value Vc1 for said three-phase inverter, and a detected current value of the three-phase motor;
controlling the three-phase inverter by single-phase alternating current excitation based on said single-phase alternating current excitation signals so as to output single-phase alternating current to the three-phase motor;
calculating an active power component of current Iq and a reactive power component of current Id for the three-phase motor based on a phase value obtained by integrating said primary frequency command and a detected current value of the three-phase motor controlled in the manner of the single-phase alternating current excitation; and
measuring a combined resistance (r1 +r2) of primary resistance r1 and secondary resistance r2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Iq and a value (Id2 +Iq2), and a combined leakage inductance (l1 +l2) of primary leakage inductance l and secondary leakage inductance l2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Id and a value ω
1 (Id2 +Iq2).
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Accused Products
Abstract
An inverter corrects an output voltage in accordance with the magnitude of output voltage error due to a dead time and an ON-state voltage drop in power elements so as to energize an AC motor in a manner of single phase alternating current excitation, by calculating an active component of current Iq and a reactive component of current Id from the phase θ of an excitation voltage vector and a detected instantaneous current value iu, and by measuring characteristic constants of the motor, including a combined resistance (r1 +r2) and a combined leakage inductance (l1 +l2), from an excitation voltage command value Vc1, Id and Iq. The measured values are used as the control constants for a speed sensorless vector control. Further, the resistances r1, r2, and a self-inductance L1, which are control constants, can be obtained based on the component in a primary voltage vector direction of a primary current vector Iq'"'"' and the component π/2 delayed from the primary voltage vector direction of the primary current vector Id'"'"'. In this way, the characteristic constants can be accurately measured without any inverter output voltage sensor.
51 Citations
8 Claims
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1. A method of measuring characteristic constants of a three-phase alternating current motor controlled by an inverter apparatus including a three-phase inverter for converting a direct current voltage into a three-phase alternating current so as to supply the three-phase alternating current to said three-phase motor and a controller for controlling the magnitude and pulse-width of an output voltage of said three-phase inverter, the method comprising the steps of:
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producing single-phase alternating current excitation signals based on a primary frequency command value ω
1 and a primary voltage command value Vc1 for said three-phase inverter, and a detected current value of the three-phase motor;controlling the three-phase inverter by single-phase alternating current excitation based on said single-phase alternating current excitation signals so as to output single-phase alternating current to the three-phase motor; calculating an active power component of current Iq and a reactive power component of current Id for the three-phase motor based on a phase value obtained by integrating said primary frequency command and a detected current value of the three-phase motor controlled in the manner of the single-phase alternating current excitation; and measuring a combined resistance (r1 +r2) of primary resistance r1 and secondary resistance r2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Iq and a value (Id2 +Iq2), and a combined leakage inductance (l1 +l2) of primary leakage inductance l and secondary leakage inductance l2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Id and a value ω
1 (Id2 +Iq2). - View Dependent Claims (2, 3, 4, 5)
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6. A controller for controlling a three-phase alternating current motor using an inverter apparatus comprising:
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a three-phase inverter for converting direct current voltage into a three-phase alternating current so as to supply the three-phase alternating current to said motor; and a controller for controlling the magnitude and pulse-width of an output voltage of said inverter said controller comprising; (a) means for producing single-phase alternating current excitation signals based on a primary frequency command value ω
1 and a primary voltage command value Vc1 for said three-phase inverter, and a detected current value of the three-phase motor;(b) means for controlling the three-phase inverter by single-phase alternating current excitation in response to said single-phase alternating current excitation signals so as to output single-phase alternating current to the three-phase motor; (c) means for calculating an active power component of current Iq and a reactive power component of current Id for the three-phase motor based on a phase value obtained by integrating said primary frequency command and a detected current value of the three-phase motor controlled by single-phase alternating current excitation; and (d) means for measuring a combined resistance (r1 +r2) of primary resistance r1 and secondary resistance r2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Iq and a value (Id2 +Iq2), and a combined leakage inductance (l1 +l2) of primary leakage inductance l1 and secondary leakage inductance l2 of the three-phase motor by calculating a ratio of a value Vc1 ·
Id and a value ω
1 (Id2 +Iq2). - View Dependent Claims (7, 8)
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Specification