Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
  • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
  • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
  • H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
  • H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
  • H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
  • H02P7/29—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using pulse modulation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60S—SERVICING, CLEANING, REPAIRING, SUPPORTING, LIFTING, OR MANOEUVRING OF VEHICLES, NOT OTHERWISE PROVIDED FOR
  • B60S1/00—Cleaning of vehicles
  • B60S1/02—Cleaning windscreens, windows or optical devices
  • B60S1/04—Wipers or the like, e.g. scrapers
  • B60S1/06—Wipers or the like, e.g. scrapers characterised by the drive
  • B60S1/08—Wipers or the like, e.g. scrapers characterised by the drive electrically driven

Definitions

• the present invention relates to a method of electronic regulation of an electric motor.
• the present invention relates more particularly to a method of electronic regulation of an electric motor, in particular of a motor of a wiping mechanism for driving at least one wiper, or arm, of wiping moving on a glazed surface, of the type in which a control device supplies the motor with voltage by pulses of determined durations, each pulse duration determining a characteristic curve, substantially rectilinear, of operating points corresponding to doublets of values, respectively of the torque and the speed angular of the motor, between two limit points corresponding, on the one hand, to an angular speed at zero torque and, on the other hand, to a torque at zero speed.
• U represents the supply voltage of the motor
• E its induced electromotive force
• R the resistance of its armature
• I the intensity of the current
• K represents the electromagnetic constant
• ⁇ the angular speed of the motor
• Cm K. l (3)
• Cm represents the electromagnetic torque or torque of the motor.
• the characteristic curve C a of the angular speed ⁇ as a function of the torque Cm is linked to a voltage value U.
• armature references which each correspond to a separate application of the wiping motor, so that the performance of the wiping motor is adapted to models of separate motor vehicle.
• the invention also aims to allow the use of a single motor armature for several applications having different speed characteristics, without being penalized in terms of motor torque.
• the invention provides an electronic regulation method of the type described above, characterized in that the voltage pulse duration is controlled as a function of the measured value of the intensity of the current supplied to the motor, from so as to obtain each doublet of values, or operating point, requested.
• the pulse duration is indexed on threshold values of the current intensity
• the number of current step values can increase with the value of the difference between the maximum angular speed at zero torque of the motor, defined by design, and the angular speed at zero torque requested;
• each level can be close to zero so that the associated level corresponds substantially to a point value
• the pulse duration is controlled so as to follow overall a theoretical characteristic curve connecting the angular speed at zero torque requested with the torque at zero speed requested;
• the theoretical characteristic curve is a straight line which connects the angular speed at zero torque requested to the torque at zero speed requested;
• the pulse duration is controlled so as to follow overall, within the limits of the physical capacities of the motor defined by design, a straight line which connects the angular speed at zero torque requested to a virtual motor torque at zero speed, the virtual motor torque at zero speed being greater than the maximum torque at zero speed, so that the angular speed is substantially stable as long that the engine torque is less than a limit value defined by design;
• the torque at zero speed requested is the maximum torque at zero speed of the engine which is defined by design
• the values of the pulse duration as a function of the values of the current intensity are stored in a table whose content varies according to the required operating points of the motor, and in that the duration of the impulse following the indications in the table;
• the control device calculates the pulse duration to be applied to the motor, by means of a transfer function, the transfer function varying according to the requested operating points of the motor; - the required operating points of the motor depend in particular on the position of the wiper, or arm, of wiping on the glass surface;
• the requested operating points are determined so as to reduce the kinetic energy stored by the wiper blade, when it arrives near one end of the swept surface;
• FIG. 3 is a diagram which represents the characteristic curves of the angular speed of the motor as a function of the motor torque corresponding to the maximum duration of the voltage pulse and to the minimum duration of the voltage pulse;
• Figure 4 is a diagram similar to that of Figure 3 which shows two examples of characteristic curves constructed from two tables associating with each current intensity level a pulse duration;
• FIG. 5 is a diagram which represents the pulse durations as a function of the current levels contained in the two tables used in Figure 4;
• Figure 6 is a diagram similar to that of Figure 4 which illustrates an alternative embodiment of the invention in which the characteristic curves follow a straight line passing through a value of virtual torque at zero speed;
• FIG. 7 is a diagram similar to that of FIG. 5 which represents the current / voltage tables used to construct the characteristic curves of FIG. 6.
• FIG. 2 shows a control device 10 which is provided for controlling the electric motor 12 of a wiping mechanism (not shown) according to a method in accordance with the teachings of the invention.
• the wiping mechanism for example, drives a wiper blade which moves on a glass surface.
• the control device 10 here comprises an electronic control unit 14 which controls the device supply 16 of the motor 12, and storage means 18.
• the supply device 16 supplies the motor 12 with a supply voltage U in the form of pulses of fixed amplitude U a the duration Di of which can vary with respect to a given period of time T.
• the motor 12 Because of its high time constant with respect to the period T, the motor 12 operates as if it were continuously supplied with a voltage U m0 y which corresponds to an average value of the voltage U a during the period T, the value of the angular speed ⁇ of the motor 12 then adapting to this average voltage U m0 y.
• the motor 12 is for example defined to operate under a voltage U a of 13 volts.
• the voltage pulse U a can extend for example over half of the period T.
• the average voltage U av "seen" by the motor 12 is then 6.5 volts.
• the supply device 1 6 can therefore modify the supply voltage U of the motor 12 by modulation of the pulse duration Di, or "Puise Width Modulation” (PWM).
• PWM Pulise Width Modulation
• the pulse duration Di will be expressed as a percentage which corresponds to the ratio of the duration of the pulse Di of voltage U a by the duration of the period T.
• each pulse duration Di determines a supply voltage U, and therefore a characteristic curve C x , substantially rectilinear, of operating points corresponding to doublets of values, respectively of the torque Cm and the angular speed ⁇ of the motor 12, between two limit points A and B corresponding to the angular speed ⁇ o at zero torque, and to the torque Cm 0 at zero speed respectively.
• a characteristic curve C x is shown in FIG. 3.
• the angular speed ⁇ 0 at zero torque is the angular speed ⁇ of the motor 12 without load, that is to say when it does not meet a resistant torque.
• characteristic curves C x of the motor 12 are substantially parallel to one another.
• the motor 12 Due in particular to the characteristics of its armature, the motor 12, by design, "accepts" a maximum angular speed ⁇ max at zero torque, a minimum angular speed comm at zero torque, and a maximum torque Cm max at zero speed.
• the maximum angular speed ⁇ max at zero torque and the maximum torque Cm ma at zero speed are connected by a straight upper curve C SU p characteristic of the motor 12, represented in FIG. 3, which illustrates the possible operating points of the motor 12 for a maximum supply voltage U ma , that is to say for a pulse duration Di of 100%.
• the upper curve C SU p is parallel to the characteristic curves C x .
• the lower curve Cj n f which passes through the minimum angular speed ⁇ min at zero torque, represented in FIG. 3, corresponding to a minimum pulse duration Di accepted by the motor 12, therefore determines a minimum torque Cm m j n at speed nothing.
• the electronic unit 14 controls the duration of the voltage pulse Di as a function of the value of the torque Cm applied by the motor 12, so as to obtain the required operating points, in order to respond at best the requirements of the current application.
• the torque Cm applied by the motor is measured indirectly by measuring the intensity of the current I supplying the motor 12.
• the intensity of the current I is a linear function of the couple Cm.
• the supply intensity I therefore does not vary with the supply voltage U.
• the measurements of the current intensity I can change due to temperature variations inside the motor 12, which have an impact on the internal resistance of motor 12, and therefore on the current consumed, or else due to the accelerations of motor 12.
• the duration d the pulse Di is indexed on step values Pi of the intensity of the current I, and not on the raw measured value.
• the content of this TI / DI table varies so as to adapt the performance of the engine 12 to the application for which it is used.
• the current / pulse table T l Di is stored by the storage means 18 of the control device 10 of the motor 12.
• the storage means 18 consist of a programmable electronic memory of the EEPROM (Electronically Erasable Programmable Read-Only Memory) type.
• EEPROM Electrically Erasable Programmable Read-Only Memory
• the angular speed ⁇ o at zero torque and the torque Cm 0 at zero speed which the motor 12 must supply are defined.
• D i the current / pulse table T
• the term “constructed curve” will denote the curve C x obtained from the current / pulse table T ⁇ / D ⁇ .
• the maximum torque Cm max of the motor 12 is chosen, which always makes it possible to benefit from the maximum available torque.
• FIG. 4 shows two examples Ci, C 2 of curves constructed from the values of two associated current / pulse tables TI / DI. These two current / pulse tables T
• the curve C ⁇ in FIG. 5, which illustrates the table TI / DI used to construct the curve Ci, is therefore a stepped curve which rises with the increase in the intensity of the current I, that is to say with l 'increase in engine torque Cm.
• the constructed curve d of FIG. 4 is not continuous since it is formed of parallel portions of characteristic curve C x which correspond respectively to each of the pulse durations Di contained in the table T
• the constructed curve Ci generally follows a theoretical characteristic curve which here relates rectilinearly, the angular speed ⁇ 0 at chosen zero torque, here ⁇ i, and the maximum torque Cm max at zero speed. We proceed in a similar way to obtain the second constructed curve C 2 .
• an angular speed ⁇ 2 with zero torque has been chosen which is equal to the minimum angular speed ⁇ m j n of the motor 12, a number of bearings Pi equal to thirteen, the pulse durations Di then ranging from about 35% to 100%.
• is variable and depends on the angular speed ⁇ o at zero torque required, so that the number of current steps P
• a maximum step value E of pulse duration Di for example 3%, can be defined, which here results in a number of steps Pi which can vary from twelve to twenty-eight.
• the size of the current steps Pi is substantially constant.
• a current / pulse table TI / DI can be provided in which the size of the current steps P
• the size, or width, of the bearings Pi can be reduced until they correspond substantially at point values, which makes it possible to smooth the corresponding constructed curve (Ci or C 2 ).
• control device 10 controls the supply device 16 so that it supplies the motor 12 with a minimum voltage U m in which corresponds to a minimum voltage pulse duration Di.
• the value of the intensity I of the current consumed by the motor 12 is then minimal, that is to say that it is contained in the first current level P M.
• the motor 12 By driving the wiper blade, the motor 12 encounters a resistant torque, which causes an increase in the intensity of the current I.
• the control device 10 permanently measures the value of the intensity of the current I, as soon as that -ci exceeds the threshold value Isi separating the first P and the second P
• the electronic unit 14 controls the supply device 16 so that it increases the value of the pulse duration Di.
• the increase in the pulse duration Di here makes it possible to reduce the speed loss ⁇ of the motor 12, due to the resistive torque encountered.
• the electronic unit 14 adapts the value of the pulse duration Di to the value of the current I measured, according to the indications provided by the memory 18.
• the electronic unit 14 controls the reduction in the value of the pulse duration Di, which makes it possible to attenuate the increase in the angular speed ⁇ of the motor 12 , due to the sudden decrease in the resistive torque.
• the method according to the invention therefore makes it possible to adjust the angular speed ⁇ of the motor to the resistive torque encountered, so as to avoid sudden acceleration or sudden deceleration of the wiper blade.
• an alternative embodiment of the invention which is illustrated by FIGS. 6 and 7, it is also possible to control the motor 12 so that it retains an angular speed ⁇ substantially stable over a large range of its operation.
• a “virtual” zero speed torque Crrivir is defined which is much greater than the maximum torque Cm max accepted by the motor 12.
• a curve C 3 is then constructed in a similar manner to the curve Ci in FIG. 4.
• the curve C 3 generally follows a straight line D 3 connecting the angular speed ⁇ o at zero torque, here ⁇ 3 , and the virtual torque Cm V ir-
• the straight line D 3 extends far to the right in FIG. 6, so that it is slightly inclined relative to the horizontal.
• the first portion of the curve C3, located between the zero torque speed (point A) and its point of intersection J with the upper curve Csup, is therefore close to the horizontal. Consequently, between point A and point J, the motor 12 operates with an angular speed ⁇ substantially stable, whatever the resistive torque applied to the motor 12.
• FIG. 6 also shows a curve C 4 ⁇ which is constructed in a similar manner to curve C 3 , but whose angular speed ⁇ at zero torque is substantially equal to the minimum angular speed ⁇ m ⁇ n of the motor 12.
• the curves constructed Ci, C 2 in FIG. 4 are constructed from current / pulse tables T
• This alternative embodiment makes it possible to regulate the speed ⁇ of the motor 12 so that it is substantially constant, without the need to add a speed sensor of the motor 12.
• the adaptation of the motor 12 to each application essentially consists in memorizing a current / pulse table TI / DI which is adapted to the desired application, in particular in terms of angular speed ⁇ o at zero torque.
• the adaptation of the motor 12 to each application is therefore carried out only by means of the electronic control of the motor 12, and not by the dimensioning of the components of the motor 12.
• the method according to the invention also makes it possible to easily correct the performance dispersions between identical motors 12, at the output of the production lines, since it suffices to program the control device 10 so as to obtain for example a angular speed ⁇ o at identical zero torque for all the motors 12.
• the motor 12 includes an electronic switching device for switching from a small angular speed PV to a high angular speed GV.
• the invention allows in particular a smooth rise of the wiper blade on a ramp corresponding to the parking position, since it is possible to control the angular speed ⁇ of the motor 12, while maintaining a maximum motor torque Cm.
• the method according to the invention makes it possible to brake the motor 12 when the control device 10 measures a negative current, that is to say in the case where the motor 12 is generating, for example following a blow Wind.
• the electronic unit 14 can also control the pulse duration Di as a function of the position of the wiper blade on the glass surface.
• the electronic unit 14 can determine the position of the wiper blade by means of a sensor 20 which is shown in FIG. 2. This sensor measures, for example, the angular position of the output shaft of the motor 12.
• the operating points of the motor 12 are determined so as to reduce the kinetic energy stored by the wiper blade, or wiper arm, when it arrives near one end of the swept surface, that is to say near the so-called fixed stop point (AF) and the point said opposite to the fixed stop (OAF).
• the operating points then define an angular speed profile ⁇ as a function, for example, of the angular position of the output shaft of the motor 12.
• the electronic unit 14 can control the supply device 16 so that the motor 12 operates according to operating points which generally follow a non-linear theoretical characteristic curve C y between an angular speed ⁇ 0 at zero torque and a maximum torque Cm 0 at zero speed chosen.
• the invention therefore makes it possible to make maximum use of the mechanical capacities of the motor 12 by precisely defining each of its operating points.
• the electronic unit 14 calculates, at regular time intervals, the pulse duration Di to be applied to the motor 12, by means of a transfer function.
• the transfer function can vary depending on the operating points requested from the motor 12.
• This variant makes it possible to continuously adapt the value of the pulse duration Di to the value of the current intensity I measured, without resorting to current steps P
• the storage means 18 are not essential since the transfer functions can be programmed directly in the electronic control unit 14, for example by means of an equation.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Power Engineering (AREA)
• Control Of Direct Current Motors (AREA)
• Control Of Electric Motors In General (AREA)

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• 2001
  • 2001-04-30 FR FR0106145A patent/FR2824204B1/fr not_active Expired - Fee Related
• 2002
  • 2002-04-25 EP EP02726284A patent/EP1383670A1/de not_active Withdrawn
  • 2002-04-25 MX MXPA03009928A patent/MXPA03009928A/es active IP Right Grant
  • 2002-04-25 KR KR10-2003-7014190A patent/KR20040015215A/ko not_active Application Discontinuation
  • 2002-04-25 CN CNB028087461A patent/CN1214938C/zh not_active Expired - Fee Related
  • 2002-04-25 JP JP2002585248A patent/JP2004538196A/ja active Pending
  • 2002-04-25 PL PL02366737A patent/PL366737A1/xx unknown
  • 2002-04-25 WO PCT/FR2002/001447 patent/WO2002087934A1/fr not_active Application Discontinuation
  • 2002-04-25 US US10/476,358 patent/US20040145331A1/en not_active Abandoned

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