EP0616693A1 - Procede de determination de l'inductance - Google Patents

Procede de determination de l'inductance

Info

Publication number
EP0616693A1
EP0616693A1 EP92924744A EP92924744A EP0616693A1 EP 0616693 A1 EP0616693 A1 EP 0616693A1 EP 92924744 A EP92924744 A EP 92924744A EP 92924744 A EP92924744 A EP 92924744A EP 0616693 A1 EP0616693 A1 EP 0616693A1
Authority
EP
European Patent Office
Prior art keywords
electric circuit
inductance
electric
dll
actuator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92924744A
Other languages
German (de)
English (en)
Inventor
Henrik Huovila
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valtion Teknillinen Tutkimuskeskus
Original Assignee
Valtion Teknillinen Tutkimuskeskus
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valtion Teknillinen Tutkimuskeskus filed Critical Valtion Teknillinen Tutkimuskeskus
Publication of EP0616693A1 publication Critical patent/EP0616693A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2611—Measuring inductance

Definitions

  • the present invention relates to a method for deter ⁇ mination of inductance by means of an electric circuit or a like subjected to the action of a control system, the inductance being determined by using a measuring system to measure one or more parameters, such as the intensity, voltage, electromotive force and/or the like of electric current running in the electric circuit or a like, the control system comprising at least one electric-current chopping control element, such as one or more transistors or the like, whereby an electric-current supply prevailing in the electric circuit or the like is used to generate in the electric circuit or the like or at least in its inductive section, at least two voltages of substantially dif ⁇ ferent intensities, depending on the chopping phase, i.e. the on-phase and the off-phase, of the control element.
  • a measuring system to measure one or more parameters, such as the intensity, voltage, electromotive force and/or the like of electric current running in the electric circuit or a like
  • the control system comprising at least one electric-current c
  • a method of the invention is particularly suitable for operating and/or controlling various actuators, such as motors, valves, clutches, magnetic bearings or the like, the functions thereof being based on the deter- mination of a position of a moving actuator component, such as a valve rod, a motor rotor or a like, on the basis of an induction change occurring in an electric circuit.
  • actuators such as motors, valves, clutches, magnetic bearings or the like
  • a method based on the determination or the change of inductance is currently applied e.g. in the control of hydraulic and pneumatic valves.
  • the valve is provided with a separate winding system, comprising for example a primary winding and two secondary windings.
  • the position of a valve rod is determined by means of a metallic indicator, which is in contact with the rod and which, upon the rod movement, performs a corresponding movement between the primary and secondary windings included in the winding system.
  • the mutual signal amplitudes of the secondary windings differ from each other, and on the basis of this, the rod position can be determined e.g. by calculation.
  • a method of the above type has been exploited e.g. in a so-called LVDT-sensor.
  • so-called brushless direct-current motors are currently provided with a so-called Hall sensor for measuring the commutating position of a motor and for controlling the motor.
  • the Hall sensor is a magnetic-fieId sensor, which is mounted on a motor in connection with the rotor.
  • the rotor is required to have a certain type of, e.g. asymmetric construction for alternating the magnetic field periodically, depending on the rotor position.
  • each pole of the motor is continuosuly operated basically in two successive phases, the pole operating in the first phase like a motor and in the second phase like a generator.
  • the commutating position of the pole can be determined for reversing its operation back to that of a motor.
  • a problem in this type of method is that at low rotating speeds, as a result of low kinetic energy, the amplitude to be measured is also very low, which is why the method cannot be applied at speeds lower than a certain speed limit.
  • the equipment applying this method requires the use of e.g. separate actuating circuits at low rotating speeds of a motor, as in connection with its starting procedure or operation stoppage.
  • An object of the method of this invention is to provide a decisive improvement on the above drawbacks and thus to substantially raise the available prior art.
  • a method of the invention is primarily characterized in that inductance is determined at least during said on- and off-phases on the basis of the intensity changes of voltages and/or electric current occurring at least in the inductive section of the electric circuit or the like.
  • the most important advantages gained by a method of the invention include simplicity and operating reliability, whereby it is possible to replace the current methods which require certain positioning and operating conditions.
  • a "comprehensive" method of the invention can be employed in most diversified applications in a manner substantially more effective than the currently available methods, e.g. by applying modern tehcnology fully automatically.
  • a method of the invention does not significantly increase the external dimensions or necessary wiring systems of an actuator unlike most of the corresponding methods currently used.
  • a method of the invention can be adapted to function on the basis of a current-supply circuit included directly in an actuator.
  • fig. 1 shows basically a diagram of a simple electric circuit for applying a method of the invention
  • fig. 2 illustrates symbols (a, b, c, d) clarifying principles of the method
  • fig. 3 shows a brushless direct-current motor as one exemplary embodiment of the method
  • fig. 4 shows a valve, a clutch or a like for the same purpose
  • fig. 5 shows a magnetic bearing for the same purpose.
  • a method of the invention is intended for determination of inductance by means of an electric circuit 1 subjected to the action of a control system 2.
  • a measuring system 3 is used for measuring one or more parameters, such as intensity I, voltage U, electromotive force and/or the like of an electric current traveling in electric circuit 1.
  • the control system 2 includes an electric- current chopping control element 2a, such as one or more transistors or the like, whereby a current supply I, U operating in electric circuit 1 is capable of producing two voltages Ul, U2 of substantially dif ⁇ ferent intensities in the inductive section i of electric circuit l in response to the chopping phase, i.e.
  • inductance L is determined during said on- and off-phases in response to voltages Ul, U2 prevailing in the inductive section i of electric circuit 1 and/or electric-current intensity changes dll, dI2 occurring therein.
  • Fig. 1 illustrates in principle a simple electric circuit 1, which represents for example a circuit extending through one 6a of the coils in a single couple of electromotor poles.
  • coil 6a its winding provides an inductive element L and a conductor used in the winding provides a resistive element R.
  • such wirings or circuits are also provided with a diode, indicated by reference numeral 4 and facilitating in one direction the by-pass of coil 6a.
  • the by-pass it is possible to create between the contact points X of diode 4 the inductive section i of electric circuit 1 operating as follows.
  • the transistor 2a serving as a control element can be used to subject the inductive section i of circuit 1 to the action of two alternating voltages, a first voltage Ul and a second voltage U2.
  • inductance L is then determined by way of calculation on the basis of the relative deviations between first voltage Ul and second voltage U2 of the electric current as well as corresponding intensity change rates dll/dt and dI2/dt of the electric current.
  • the transistor 2a is operated at a high frequency, at least > 1 kHz, typically > 20 kHz, whereby the electric current intensities dll and dI2 change during said on- and off-phases in a substantially linear fashion.
  • inductance L it is possible to evaluate the change of electric current intensity during on- and off-phases by means of straight lines dll and dI2, whose oppositely signed slopes correspond to intensity change rates dll/dt, dI2/dt.
  • the relative deviation e of change rates can be determined as a difference between the slopes.
  • inductance L is determined on the basis of the inverse value of a difference: dll/dt - dI2/dt between the current change rates determined from the inductive section i of electric circuit 1.
  • Fig. 2 clarifies the application of the method by showing symbols from two electric circuits l j , 1. j , having inductances different from each other.
  • Figs. 2a illustrate alternating first and second voltages Ul, U2 during the on- and off-phases.
  • Figs. 2b il ⁇ lustrate corresponding linear changes dll, dI2 in current intensity when using a sufficiently high frequency.
  • Figs. 2c illustrate the rate per time dll/dt, dI2/dt of the linear changes occurring during the corresponding phases, said rates corresponding to the slopes of the straight lines shown in figs. 2b.
  • Figs. 2d illustrate the inverse values of inductance L determined by way of calculation on the above basis. In the illustrated cases, the inductance L t j of electric circuit l j j is 2 x the inductance L j of electric circuit l j .
  • the basic allegation is to have such a high chopping frequency that the current intensity can be presumed to change linearly during each on- and off-phase.
  • inductance L e.g. basic ⁇ ally as shown in fig.
  • a calculating element 5, such as a microprocessor, an analogous circuit or a like is used to provide the inductive section i of an electric circuit 1 included in an actuator 6 with measuring elements 3a, included in a measuring system 3 and fitted at least in a data transmitting communi ⁇ cation with said calculating element 5, for measuring and/or determining at least a change dll, dI2 in the intensity of electric current and a voltage Ul, U2 relative to time.
  • a method of the invention can also be applied as described with the above positional sensors, whereby an electric circuit or a section thereof functioning on a simple principle of the method is adapted to operate in a particular actuator.
  • an electric circuit or a section thereof operating in accordance with a method of the invention can also be used to replace a sensor previously employed in said actuator.
  • inductance of an operating coil included therein changes in response to the position of a moving component.
  • the operation of an actuator essentially involves a winding, such as a solenoid, a coil or a like, which means that also its current-supply circuit has a varying inductance, representing directly e.g. the position of a moving component.
  • a particularly preferred application for a method of the invention is an actuator, whose electric circuit 1 dealing essentially with power supply is chopped by means of a transistor 2a.
  • inductance L can be directly determined from electric circuit 1, included in an actuator and fitted with measuring elements 3a e.g. according to the above- described principle.
  • FIGs. 3, 4 and 5 illustrate practical applications for the method carried out on the above principles.
  • Fig. 3 shows how the method is applied in connection with a reluctance motor representing a direct-current motor.
  • the inductance L determined mathematically by means of calculating element 5 has an effect through the action of control system 2 and a control element 2b included therein on the operation of said motor in a manner that at a certain threshold value of the calculable inductance L to be determined during the rotating motion of a rotor 7, i.e. in a certain angular position of rotor 7, the polarity of a stator 8 is switched (6a, -> 6a2) for maintaining the rotating motion.
  • Fig. 4 is a typical practical application showing e.g.
  • a valve or a clutch whose rod 9 is controlled by using a magnetic field generated by means of a solenoid 6a. Even in this case, a method of the invention is very simple to apply since the position of rod 9 can be determined directly from electric circuit 1 supplying current to the solenoid.
  • Fig. 5 illustrates yet another example of the applica- tion of a method of the invention in connection with a conventional magnetic bearing included in a moving component 10, such as a shaft or a like, said appli ⁇ cation corresponding in its operating principle and in its benefits to those described above.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Ac Motors In General (AREA)
  • Control Of Linear Motors (AREA)
  • Control Of Electric Motors In General (AREA)

Abstract

Le procédé selon l'invention est conçu pour la détermination de l'inductance au moyen d'un circuit électrique (1) sujet à l'action d'un système de commande (2). De manière à déterminer l'inductance (L), un système de mesure (3) est utilisé pour mesurer un ou plusieurs paramètres, tels que l'intensité (I), la tension (U), force électromotrice et/ou les paramètres similaires du courant électrique passant dans le circuit électrique (1). Le système de commande (2) comporte un élement de commande de découpage (2a) du courant électrique tel qu'un ou plusieurs transistors ou éléments similaires, au moyen duquel une alimentation en courant (I, U) fonctionnent dans le circuit électrique (1) est utilisée pour produire dans la section inductive (i) du circuit électrique (1) au minimun deux tensions (U1, U2) d'intensités substantiellement différentes selon la phase de découpage, par exemple la phase "on" et la phase "off" de l'élément de commande (2a). Ainsi, selon l'invention, l'inductance (L) est déterminée sur la base des tensions (U1, U2) présentes dans la section inductive (i) du circuit électrique (1) et/ou sur la base des changements d'intensité du courant électrique (dI1, dI2) ayant lieu dans cette section.
EP92924744A 1991-12-10 1992-12-09 Procede de determination de l'inductance Withdrawn EP0616693A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI915799 1991-12-10
FI915799A FI89636C (fi) 1991-12-10 1991-12-10 Foerfarande foer bestaemning av induktans
PCT/FI1992/000334 WO1993012437A1 (fr) 1991-12-10 1992-12-09 Procede de determination de l'inductance

Publications (1)

Publication Number Publication Date
EP0616693A1 true EP0616693A1 (fr) 1994-09-28

Family

ID=8533641

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92924744A Withdrawn EP0616693A1 (fr) 1991-12-10 1992-12-09 Procede de determination de l'inductance

Country Status (5)

Country Link
EP (1) EP0616693A1 (fr)
AU (1) AU3088392A (fr)
CA (1) CA2125562A1 (fr)
FI (1) FI89636C (fr)
WO (1) WO1993012437A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009001400A1 (de) 2009-03-09 2010-09-16 Robert Bosch Gmbh Verfahren zur Überwachung der elektrischen Eigenschaften eines getaktet gesteuerten Lastkreises und Schaltungsanordnung zur Durchführung des Verfahrens
CN103728499B (zh) * 2013-11-15 2017-02-01 王泉 一种使用三相全控整流桥测量直流电机电枢回路电感方法
CN110328160A (zh) * 2019-08-01 2019-10-15 中山市博测达电子科技有限公司 小型贴片电感自动测试设备

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4219740A (en) * 1979-01-12 1980-08-26 Eldec Corporation Proximity sensing system and inductance measuring technique
DE2939665A1 (de) * 1979-09-29 1981-04-16 Robert Bosch Gmbh, 7000 Stuttgart Auswerteschaltung fuer einen halbdifferential-kurzschluss-geber
EP0126846B1 (fr) * 1983-04-21 1990-08-01 WABCO Westinghouse Fahrzeugbremsen GmbH Capteur inductif
DE3807015A1 (de) * 1987-04-29 1988-11-10 Wabco Westinghouse Fahrzeug Verfahren und schaltung zur messung einer induktivitaet
GB9002811D0 (en) * 1990-02-08 1990-04-04 Du Pont Uk Inductance and resistance measuring circuit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9312437A1 *

Also Published As

Publication number Publication date
CA2125562A1 (fr) 1993-06-24
FI915799A0 (fi) 1991-12-10
FI89636B (fi) 1993-07-15
AU3088392A (en) 1993-07-19
FI89636C (fi) 1993-10-25
WO1993012437A1 (fr) 1993-06-24

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