Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Patent
1998-06-29
2000-12-12
Karlsen, Ernest
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
3241581, G01R 3126
Patent
active
061604143
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an abnormality diagnosis method for diagnosing failures and the like of various circuit components of an inverter drive control apparatus for drivingly controlling a motor.
BACKGROUND ART
In a typical method for detecting abnormalities such as failures in circuit components and elements in an electric circuit, current, voltage, resistance, etc. of those spots which are supposed to be abnormal are measured by means of a tester, ammeter, voltmeter, etc. to detect abnormalities. A similar method is conventionally used to detect and diagnose abnormalities in an inverter drive control apparatus for drivingly controlling a motor by means of an inverter.
According to the aforesaid abnormality diagnosis method using the tester and the like, measurement must be carried out after removing covers for supposedly abnormal spots and other members that hinder the measurement. If no abnormalities are detected as a result of the measurement, other spots must be measured in like manner after reassembling the removed member. Thus, the detection and diagnosis of abnormalities require much time and labor.
DISCLOSURE OF THE INVENTION
The object of the present invention is to make easier the detection and diagnosis of abnormalities in various circuit components that constitute an inverter drive control apparatus for drivingly controlling a motor.
In order to achieve the above object, an abnormality diagnosis method according to the present invention for diagnosing the abnormalities of the circuit components of an inverter drive control apparatus for drivingly controlling a motor comprises first turning on only a selected one of a plurality of switching devices constituting an inverter, then supplying a current between selected phases, and troubleshooting the circuit members through which the current flows in accordance with detection results detected by current detection circuits corresponding to the phases.
Preferably, the selection of the switching device to be turned on and the selection of the phases associated therewith are carried out at least twice in different combinations, and the circuit members to be concluded to be abnormal are identified by comparing the results of detection in the current detection circuit for each cycle.
Preferably, the current supplied for abnormality diagnosis is control pulses with a given width. Further, the detection results detected by the current detection circuits are current leading-edge waveforms or trailing-edge waveforms.
According to the present invention, as described above, abnormalities can be detected and diagnosed for transistors as the switching devices in the drive and control apparatus for the motor using the inverter, diodes connected in parallel with the transistors, the current detection circuits for detecting the current flowing through windings for individual phases, cables connected to the windings for the individual phases of the motor, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram showing the principal part of a motor drive and control apparatus using an inverter to which one embodiment of the present invention is applied; and
FIG. 2 is a diagram for illustrating detected currents according to this embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a circuit diagram showing the principal part of a drive control apparatus designed for driving and controlling a motor by means of an inverter. Connected between a positive terminal L1 and a negative terminal L2 is a DC power source by which the current from a three-phase AC power source is converted into DC current by means of a diode bridge circuit (not shown) or the like. Symbol C designates a capacitor for smoothing the voltage of the direct current obtained by conversion. Two sets of circuits, each including switching devices (transistor) and diodes connected in parallel for each phase of the motor, are connected in series between the aforesaid terminals L1 and L2. More specifically, a parallel circuit of a switching device Tr
REFERENCES:
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patent: 4659983 (1987-04-01), Jacob
patent: 5266891 (1993-11-01), Kumar et al.
patent: 5363039 (1994-11-01), Kumar et al.
patent: 5376881 (1994-12-01), Takahashi
patent: 5497095 (1996-03-01), Ueyama et al.
Matsubara Shunsuke
Yamada Yuichi
Fanuc Ltd.
Karlsen Ernest
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