FR2557744A1 - METHOD AND APPARATUS FOR PROVIDING THE CONTROL VOLTAGE OF A DIRECT CURRENT ELEVATOR MOTOR - Google Patents

Abstract

METHOD AND APPARATUS FOR DEVELOPING A CONTROL VOLTAGE OF A DC ELEVATOR MOTOR 5, THIS MOTOR BEING CONTROLLED THROUGH SEMICONDUCTOR SWITCHES IN FOUR QUADRANTS, FROM A STORAGE ENERGY 2 AT CONSTANT VOLTAGE AND ITS LOADS CONNECTED TO AN ALTERNATING CURRENT DISTRIBUTION. IN ORDER TO ENABLE A DIRECT CURRENT CONTROL, WHICH IS PARTICULARLY ADVANTAGE IN HIGH POWER APPLICATIONS, A CONSTANT FREQUENCY THREE-PHASE DISTRIBUTION VOLTAGE V1, V2, V3 IS FORMED BY THE CONVERTER CIRCUIT 3, FROM THE STORAGE VOLTAGE 'ENERGY 2, AND IT IS APPLIED TO A DIRECT CURRENT CONTROL CIRCUIT 4 WITH SWITCHED LINES IN FOUR QUADRANTS, WHICH CONTROLS THE ELEVATOR MOTOR 5.

Description

The present invention relates to a method

  and to an apparatus for developing the com- put voltage

  control of a direct current elevator motor, using semiconductor switches, which allow, by means of energy storage at constant voltage and its mo

  charge yen connected to the current distribution al-

  ternative, to control the DC motor by the

  semiconductor switches, in four quadrants.

  The DC motor has characteristics

  qualitatively superior in technology

  lifts, compared to an alternating current motor

  native. By quality is meant the absence of vibration and exact speed control. It is for this reason that fast elevators without reducers, in particular, are

  built with direct current motors exclusively.

  In rapid elevator technology, the use of a four-quadrant thyristor bridge has been adopted for the

  DC motor control. This process has now

  nant replaced the usual Ward-Leonard technique. The Nou-

  This technique is advantageous for example because of its high yield. However, it has the disadvantages of

  wrong power factor, starting currents

  surveys and the introduction of higher harmonics into the

  distribution. There is also a risk that failure to

  that of the distribution voltage blows the fuses

  and people are held captive in the elevator

be two floors.

  In order to avoid these disadvantages, provision has been made (see for example Finnish patent applications

  n 833 051 and 833 302) sending a DC voltage, pro-

  by means of a rectifier, to an energy storage which supplies the energy for the operation of the DC motor, the control signal of the current motor

  continuous being constituted by the constant tension, or inter-

  energy storage, obtained by pulse width modulation. This provides certain advantages:

  - the nominal distribution power required is low

  ble since energy also goes into storage when the elevator is stationary; since this storage charge current is quite low, the power factor and the

  higher harmonics are no longer inconveniences

  nients, - the starting current does not impose any load on the

  distribution, that is, the distribution provides only

  In addition to the system, the constant charging current of the energy storage, the elevator always has an energy reserve, namely the energy storage, so that a failure

  of the distribution does not cause the fu-

  and there is no risk of imprisoning persons

rings in the elevator.

  The best known means of energy storage

  at constant voltage are the storage battery. The bat-

  storage areas can be replaced for example by

  a flywheel, which is characterized by a capacity-

  acceptance and release of instantaneous energy greater than that of the storage battery and which requires

less maintenance.

  The pulse modulation circuits of a device

  reils of this type are generally made by means of the cir-

  cooked known thyristor, McMurray type. With the McMurray circuit, you can build usable pulse modulation systems, without the need for components

special.

  However, circuits of this type suffer from three main drawbacks: first, no

  appropriate noise suppression technique has not been developed

  developed with a satisfactory result in the case of an as-

  censor; the second drawback is the lack of a

  alternative sion, which is required on the control panel

  mande; the third disadvantage is that all the powerful

  this of the motor crosses a single thyristor and it is therefore necessary to

  large thyristors, which are expensive.

  The object of the present invention is to avoid the above drawbacks of a fast elevator with a motor

  direct current. The process according to the invention, for the ela-

  boosting the control voltage of the constant current motor

  tinu, is mainly characterized in that, starting from the voltage of the energy storage, one forms, by means of a

  converter circuit of known type, a distribution voltage

  three-phase constant frequency bution with which

  supplies a direct current control circuit to the

  tation of lines in four quadrants, of known type, which

controls the elevator motor.

  The device for implementing the method

  according to the invention, which includes semi- switches

  conductors for developing the control voltage of the

  DC motor of an elevator and a storage of

  energy at constant voltage and its charging means,

  is mainly characterized in that the tension of the sto-

  ckage of energy is connected to a converter circuit of known type, for obtaining a three-phase distribution voltage of constant frequency which is applied to a direct current control circuit with switched lines in four quadrants, of known type, for ordering

elevator motor.

  The main advantages of the invention are as follows: - in the case of the invention, the power is distributed

  between several thyristors and, like the size of thyris-

  tors is always limited, so this makes it possible to process larger powers,

  - since there is an alternating current distribution

  native three-phase, inside the device, obtained from

  energy storage battery shot, all available

  electrical components of the elevator which operate in

  rant alternatif are supplied even when the external electrical distribution is cut, these devices being able to include for example transformers, inductors and contactors,

  - the frequency of the internal distribution of the appliance

  reil may be greater than that of external distribution

  higher, which allows the use of inductors and ca-

  smaller and cheaper pacities, for the filters of

noise suppression.

  In addition to the foregoing provisions, the invention also comprises other provisions, which will emerge from

the description which follows.

  The invention will be better understood using the

  additional description which follows, which refers to the

  sins annexed in which: FIG. 1 illustrates the method of controlling a DC motor, in accordance with the invention, in an example of a circuit, FIG. 2 is a vector diagram, drawn to facilitate the understanding of the voltage graphs of the conversion part according to the invention, FIG. 3 represents the configurations of the

  phase voltages and triangle voltages of the distribution

internal burn of the device,

  FIGS. 4a to 4f represent configurations

  voltage measurements illustrating the operation of the

  DC control of Figure 3, when this circuit

  cooked is supplied with a square wave distribution voltage according to the invention, and

  Figures 5a to 5c show the configurations

  equivalent voltage, in a six-phase rectifier

  drives operating from a sinusolda- distribution

  the. It should be understood, however, that these drawings and the corresponding descriptive parts, are given solely by way of illustration of the subject of the invention, of which they do not in any way constitute a limitation.

  The operation of the apparatus according to the invention

  tion is explained below and more fully described

  the details of figure 1. Block 1 represents a char-

  geur connected to the distribution and through-

  what energy can be stored in energy storage

  energy 2, when necessary. Connection to the

  distribution is represented by the voltage U, which can be

  be a single-phase voltage since the control circuit according to the invention takes little instantaneous energy, due to the equalization effect of the energy storage 2. The charger can be put into service and stopped by

  known methods, which are not described here in detail.

  Circuit 3, shown at the top of Figure 1, is an example of a three-phase converter or inverter. In this device, the energy is supplied by the energy storage 2 to the DC motor 5, by

  through thyristors T1-T6 which constitute the

  semiconductor mutators. Generally speaking, semiconductor switches are in parallel with

  diodes D1-D6, as shown in Figure 1, for

  end and straighten the current flowing in the opposite direction,

towards energy storage.

  The components T1-T6 and D1-D6 constitute the main components of the converter 3. The real converter often contains other elements, necessary for the switching of the thyristors, unless these are not

  GTO type, with current gain on opening. In the cir-

  cooked with forced switching thyristors, shown in FIG. 1, the switching of the thyristors T1-T6 is carried out with a resonance circuit constituted by a capacitor and an inductance. The forced switching circuit is a device well known to those skilled in the art and it is therefore not necessary to describe further here the operation

  of the converter. The three-phase supply voltage pro-

  taken by converter 3 is represented by V1, V2 and

V3, in the figures.

  The lower part of FIG. 1 represents a control circuit 4 with direct current with switched lines

  in four quadrants, including a suppressor

  noise. The DC control includes

  thyristors T7-T18. These thyristors control the motor 5.

  On the motor shaft 6 is mounted a traction sheave 7 which itself sets in motion the elevator car 8

  and a counterweight 9, via cables of the

  vage 10. The noise canceling device of the DC control circuit 4 comprises the elements C1 and

  L4. The switching chokes L1-L3 also contribute

  noise suppression. The removal technique

  noise level, used here, is described in the fin-

Landes n 61252.

  The DC control circuit used

  here, is a well known device and therefore it is not de-

  written in more detail. However, we describe below

  the operating principle of the means in accordance with the

  vention. At the top of Figure 3 are illus-

  very phase voltages V1, V2 and V3 supplied by the converter circuit 3. From these phase voltages, we can calculate the triangle voltages (between phases) U1, U2 and U3, by a simple vector algebraic method, at medium formulas

U1 = V1 - V2

U2 = V3 - V1

U3 = V2 - V3

  The voltages between phases, illustrated in the section

  figure 3, are determined in this way.

  Since the supply voltage is not sinusoidal, as is usually the case, but is on the contrary

  a so-called six-step voltage, the functioning of the circuit

  control current 4 DC differs from the known mode.

  The voltages produced in rectification are represented

  by Figures 4a to 4f. Depending on the position of the point of-

  Morcing, we get a recovery situation or a reversal situation. In Figure 4a, the voltages in

  triangle U1, U2 and U3 have been assembled in the same system

  coordinate coordinates. FIGS. 4b to 4d represent rectified voltages, of variable magnitude as a function of

  the initiation time T1 to T3, and FIGS. 4e and 4f show

  have inverted voltages, of variable size in

  function of the instants of initiation T4 and T5.

  It can be seen that the configurations in FIG. 4 differ-

  clearly make usual voltage configurations ob-

  held from a sinusoidal distribution, as appears from the comparison of the curves in Figure 4 and

  Figure 5. In Figure 5, we calculated, in the same way

  Lesson illustrated in FIGS. 2 and 3, the voltage configurations of a thyristor rectifier switched from a sinusoidal distribution. The phase voltages RST in FIG. 5a give the triangle voltages indicated in FIG. 5b, which themselves give, as a function of a given ignition angle, the voltage across the terminals of the motor, indicated in FIG. 5c. This is obtained from

  of the voltage configuration of a six-pulse rectifier

  sions operating on a sinusoidal distribution, for

  a given ignition angle. We can compare the voltage re-

  shown in Figure 5c at the voltage shown in the

  Figure 4d, which is a substantially equalized rectified voltage.

  mentally directed, in the case of the present invention. It is obvious that the tension configuration is indeed

very different.

  As is clear from the above, the information

  vention is by no means limited to those of its modes of

  are implemented which have just been described explicitly;

  on the contrary, it embraces all the variants which may

  wind come to the mind of the technician in the field, without departing from the scope or the scope of the present invention.

Claims (3)

Claims   1. Method for developing the control voltage for a DC elevator motor, in which   the DC motor is controlled by switches   semiconductor torers in four quadrants, by means of an energy storage (2) at constant voltage and its charging means, the latter being connected to an alternating current distribution, characterized in that a voltage of three-phase distribution (V1, V2, V3) of constant frequency is formed by the conversion circuit (3) from the energy storage voltage (2) and supplies a circuit   direct current control (4) with switched lines in four   tre quadrants, which controls the motor (5) of the elevator.   2. Method according to claim 1, characterized in that the distribution voltage (Vl, V2, V3) obtained with   the conversion circuit (3) is a square wave.   3. Device for implementing the following process   claim 1 comprising semiconductor switches   ductors, for the development of the control voltage of a DC motor (5) of an elevator, and an energy storage (2) at constant voltage and its charging means   connected to alternating current distribution,   risky that the energy storage voltage is connected   dedicated to a converter circuit (3) of known type, for pro-   reduce a three-phase distribution voltage (V1, V2, V3) from   constant frequency, this voltage being sent to a circuit   dc control circuit (4) with switched lines   in four quadrants, of known type, to control a mo- elevator (5).