Electricity: motive power systems – With signals – meters – recorders or testing devices
Patent
1998-10-21
2000-05-23
Ro, Bentsu
Electricity: motive power systems
With signals, meters, recorders or testing devices
318798, 318801, H02P 763
Patent
active
060669349
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an induction motor controller for measuring electrical constants of a polyphase induction motor such as a primary resistance, a secondary resistance, and a leakage inductance by supplying a test power thereto with a polyphase inverter, setting a result of this measurement as parameters for driving control, and controlling driving of the polyphase induction motor.
BACKGROUND ART
For the purpose of controlling an induction motor with high precision, there is sometimes a case where such values as primary/secondary winding resistance, primary/secondary leakage inductance and mutual inductance which are electrical constants of the induction motor are required. FIG. 12 shows one of conventional technologies having functions of measuring those electrical constants and setting the constants in an induction motor controller.
FIG. 12 shows system configuration of a key section of an induction motor controller based on the conventional technology described in Japanese Patent Laid-Open Publication No. HEI 7-325132. In the figure, designated at the reference numeral 1 is an inverter, at 2 an induction motor, at 3 a current detector, at 4 a voltage detector, at 5 a magnetic flux torque control means, at 6 a no-load testing means, at 7 a DC testing means, at 8 (1) to 8 (n) a single-phase testing means respectively, at 9 a constant calculating means, at 10 a selector, and at 11 a setting storage means. The inverter 1 inputs a switching signal of output from the selector 10, operates according to the switching signal, and applies a voltage to the induction motor 2.
Next description is made for operations of measuring the secondary resistance as well as leakage inductance of this induction motor controller. The selector 10 successively selects output switching signals from a plurality of single-phase testing means 8 (1) to 8 (n), and outputs each of the selected signals to the inverter 1. A single-phase AC voltage is applied to a section between two terminals among three-phase input terminals with the induction motor 2 being at rest. Herein, it is assumed that frequencies of voltages each applied to the induction motor 2 are different from each other in n-pieces of single-phase testing means 8 (1) to 8 (n). Each of the single-phase testing means 8 (1) to 8 (n) inputs a current detected with the current detector 3 as well as a voltage detected with the voltage detector 4, obtains each magnitude as well as phase of those fundamental waves, obtains a sum (L011+L021) to (L01n+L02n) between primary and secondary leakage inductance and a sum (R11+R21) to (R1n+R2n) between primary and secondary winding resistance from those relations, and outputs the sums together with frequencies (F1 to Fn) of the voltage to the constant calculating means 9. Herein, it is assumed that the primary leakage inductance and the secondary leakage inductance are equal to each other, and that a half of the sum of the leakage inductance outputted from each of the single-phase testing means 8 (1) to 8 (n) is leakage inductance (L1 to Ln) of each of the single-phase testing means 8 (1) to 8 (n) respectively.
Further, it is assumed that the frequency changing property of leakage inductance is expressed by the following m-th-degree polynomial satisfying the condition of (m.ltoreq.n-1) and including a frequency of an applied voltage as a variable:
Herein, the leakage inductance (L1 to Ln) measured for a frequency (F1 to Fn) is substituted in the equation (1) and factors A, B, and Z can be obtained based on a method of undetermined coefficients. Then, only the factor Z as a value of a 0-th degree may be computed because a value of a frequency 0 Hz is employed, so that computation is very simple. A value for the 0-th degree in this m-th-degree polynomial is assumed to be an estimated true value L of leakage inductance. Similarly, a value for the 0-th degree in this m-th-degree polynomial is assumed to be a true value R2 of secondary winding resistance by using the secondary winding resistance (R21 to R2n) meas
REFERENCES:
patent: 4204425 (1980-05-01), Mallick, Jr.
patent: 4567419 (1986-01-01), Watanabe
patent: 4670698 (1987-06-01), Fulton et al.
patent: 4780658 (1988-10-01), Koyama
patent: 4789834 (1988-12-01), Koopman
patent: 4801877 (1989-01-01), Herrick et al.
"A Method of Calculating the Characteristics of Squirrel Cage Type Induction Motor Driven by a Nonsinusoidal Voltage Source", Tadao Fujimaki et al, pp. 108-116, Electrical Engineering in Japan, vol. 104, No. 3, 1984 .
Imanaka Akira
Kaitani Toshiyuki
Nagano Tetuaki
Shiraishi Yasuhiro
Mitsubishi Denki & Kabushiki Kaisha
Ro Bentsu
LandOfFree
Induction motor controller does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Induction motor controller, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Induction motor controller will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1839271