FR2633788A1 - METHOD AND INSTALLATION FOR ATTENUATING FIELD IN SERIES-TYPE ELECTRIC MACHINES OF ELECTRICALLY DRIVEN VEHICLES AND CIRCUIT FOR IMPLEMENTING THE METHOD - Google Patents

Abstract

a) Method and installation for attenuating the field in electric machines of the series type of electrically driven vehicles and method for implementing the method. b) Characterized in that the speed of movement of the vehicle and the presence of a field attenuation command are detected and these signals are applied to an adder 7 and in the event of a movement speed being exceeded, resistor 5. The protection and switching device 6 cooperates with a final amplifier 13 connected to an adder 7, to a generator of real value of rotation speed 10 and to an operating mode generator 11 and an on / off switch 8. c) The invention relates to a method and an installation for attenuating the field in electric machines of the series type of electrically driven vehicles, and a circuit for implementing the method.

Description

Method and installation for attenuating the field in machines

  Electric type series of vehicles with electric drive and circuit for the implementation of the method. The present invention relates to a method for attenuating the field of an electric-series machine of electric motor vehicles, according to which

  branch at least one resistance in the circuit of ex-

  quote. It is generally known in DC motors to increase the rotational speed by decreasing the magnetic field of the excitation circuit. This is done by means of a resistor placed in the excitation circuit and which reduces the

  excitation current thus decreasing the magnetic flux

  tick and the couple, so much so that as the tension of

  source, induced remains constant, rotational speed

increase.

  A possible application of this principle exists in vehicles with electric motors, for example electric forklift trucks which are driven by one or more series-type engines and

  take their energy in a battery. Engine-

  series and electrical.installation are designed for

  at low speeds, the electric forklift

  that provide a large couple and presents a

  high level. When the forklift makes a

  displacement, for example it changes the point of use

  In addition, it is desirable to increase the speed of the forklift. However, in this situation, we can not increase the speed of rotation of the engine

  and so the speed of movement of the carriage-

  forklift by plugging a resistor into

  the excitation circuit, by the driver of the machine.

  In these conditions, it is above all interesting

  for forklifts, electric, to achieve

be attenuation of the field.

  The present invention aims to limit the implementation and the cutting by the driver of the field attenuation at ranges of use in which the high speeds of movement are allowed. For this purpose, the invention relates to a method of the above type, characterized in that the speed of movement of the vehicle and the position of the vehicle are detected.

  route generator as well as the mode of operation

  of the machine-series and the presence of a

  field attenuation and apply these signals

  to an adder and in case of exceeding a

  predetermined displacement rate and a predetermined acceleration position of the command generator of

  at the same time as the order of

  suppression of the field, the resistance is connected.

  Field attenuation is not implemented

  that when specific conditions are satisfied

  your. First of all, we must have gone beyond a

  predetermined displacement speed and that the

  The transmitter issues the order to further increase the speed of travel. For this, the speed of movement and the position of the generator of road order as for example the position of the accelerator pedal

  are monitored. At the same time, the trainer must

  The vehicle is in the first or third quadrant, ie it is the acceleration phase in forward or acceleration. in reverse for engine operation, this

  which makes it necessary to monitor the operating mode

  the machine-series. It is only when all the conditions are satisfied and in addition that the driver actuates a switch that the attenuation of the field occurs. An adder notes that

  all these parameters exist to trigger the

  nuation of the field; this adder then transmits the

  where appropriate a signal. The use of such an allowance

  field shading allows higher speeds and thus greater maneuvering power with a

  less energy consumption compared to the actual

  forklift trucks with no

  not this possibility of attenuation of the field.

  In advantageous developments, some

  some of the parameters are associated with comparison thresholds

  mutation similar to a two-point regulation. This establishes a certain hysteresis between the setting

  work and the cutting of the attenuation of the field, hysteria

  resis that creates for a certain time, states

  precise commutation so that the motor can

  adjust accordingly. In addition, we avoid a movement

  of the switching protection device

  tion. Thus, it makes the speed of displacement again pass by a determined value below the chosen value so that the attenuation of the field is

implement.

  The speed of movement can also

  be reduced if the motor is overloaded by a displacement

surround on a slope.

  The position parameters of the motion command generator and the operating mode

  are associated with such switching thresholds.

  To achieve the effect described, it is advantageous to provide a switching device provided with a resistor and a protection device and

  switching device according to which the protection device

  switching and switching is connected to a final amplifier or output amplifier itself connected to an adder; the adder is itself connected to a real value generator of rotational speed, and

  to a sensor operating mode of the machine-

  series as well as a sensor detecting the position of the

  route generator and a manual switch

  che / off. Thanks to a simple logic circuit processing the parameters, it is possible to control an attenuation of the

  field for a characteristic operating state.

  The detection of the real value of the speed of rotation

  tation can be done by a pulse generator, inductive or a tachogenerator dynamo or a sensor-shaped incremental sensor mounted in the transmission or directly on the series engine; the frequency thus detected, which is proportional to the

  rotation speed is then transformed into a

  proportional to speed. The position of the

  route order generator can be determined by the

control voltage that it generates.

  Other improvements are characterized in that in field attenuation mode, when passing below a predetermined threshold of the speed of

  displacement, suppress the attenuation of the field.

  According to another characteristic of the in-

  in the field attenuation mode, when

  passes from a determined value the accelerating position

  predetermined configuration of the displacement order generator

  the field attenuation is cut off.

  According to another characteristic of the in-

  in the field attenuation mode, when the operating mode of the series machine changes from motor operation to generator operation, the field attenuation is cut off, and a circuit for carrying out the method is characterized in that the protection and switching device cooperates with an end amplifier connected to an adder to a real speed value generator and to an operating mode generator and an on / off switch. The present invention will be described below. after in more detail with the aid of an embodiment shown schematically in the single figure. A DC motor powered by a battery i is constituted by a series motor 3 by the

  corresponding arrangement of its excitation coil

  2. The electrical circuit is closed by the interruption

  4. The figure represents only the simplest

  of all electrical circuits. The elements of

  and regulation such as those required by

  example to the supply circuit of a trolley-

  fork lift, with electric motor, are not shown in the figure. The excitation circuit comprises in parallel with the excitation winding 2,

  a resistance 5 which can be connected by the arrangement

  6. This reduces the field and increases the speed

  rotation of the engine-series 3. The control of the

  The protective and switching signal 6 is only symbolically represented. An adder 7

  receives signals from different sensors that detect

  among other things, the various parameters of the instantaneous state. These are the following parameters: state of the on / off switch 8 manually operated by the driver; generator of the reference speed of rotation 9 which is associated with a predetermined speed of displacement; generator of value

  the actual speed of rotation 10 which detects the

  instantaneous displacement speed; operating type generator 11 which detects whether the motor-series operates as a generator or motor and a detector 12 for detecting the position of the road-order generator or the control voltage influenced by the position of the generator of the order of road. When all detectors or sensors provide a signal,

  the adder 7 also provides a signal to the

  final repeater 13 and this makes the amplifica-

  outlet 13 operates the protection device

  switching 6 and thus attenuates the field. The attenuation

  the field remains implemented until one

  sensors no longer provides signal to the addition-

neur 7.

Claims (4)

  1 ') Method for attenuating the field of a   electric-series machine of electric motor vehicles   that is connected to at least one resistance   this in the excitation circuit, characterized   in that the speed of movement of the vehicle is detected   cule and position of the road order generator   as well as the mode of operation of the machine-   series and the presence of a field attenuation order and these signals are applied to an adder (7) and   exceeding a predetermined speed of travel   completed and a predefined acceleration position   origin of the displacement order generator and in   this simultaneous of the order of attenuation of the field, one branch the resistor (5).   2 ') Process according to claim 1, characterized   in that in field attenuation mode, when passing below a predetermined threshold of the speed of displacement, the attenuation is suppressed. of the field.   3-) The process according to claim 1, wherein   in that in the field attenuation mode, when the predetermined acceleration position of the command generator is exceeded by a predetermined value.   displacement, one cuts the attenuation of the field.   4 ') Process according to claim 1, characterized   in the field attenuation mode, when   as the operating mode of the machine-series (3)   switch from motor operation to gener-   controller, the field attenuation is cut off.   ') Circuit for the implementation of the procedure   die according to any one of claims 1 to 4,   in which at least one resistor and at least one switching protection device are connected in parallel with the excitation winding, circuit characterized in that the protection and switching device (6) cooperates with a final amplifier (13) which is connected to an adder (7), the latter being connected to a rotational speed command value generator (9), to a real speed value generator (10) and to an operating mode generator (11) of the machine-series (3), as well as with a sensor (12) of the position of the movement command generator and a switch on / off (8).