FR2787647A1 - METHOD FOR AUTOMATIC IDENTIFICATION OF OPERATING PARAMETERS OF A LOW VOLTAGE POWER SUPPLY UNIT ADAPTABLE TO A HIGH VOLTAGE UNIT AND HIGH VOLTAGE GENERATOR DEVICE - Google Patents

Abstract

Automatic and precise identification of the characteristics of a voltage raising unit for determining the operating parameters of the low voltage power supply unit supplying the voltage raising unit. According to the invention, the intrinsic characteristics of the voltage rise unit are stored in a read-only memory (M1) contained in the voltage rise unit (13) and they are read under the control of a processor (19) contained in the unit low voltage power supply (12) to determine the operating parameters thereof.

Description

The invention relates to a method for automatic identification of

  operating parameters of an adaptable low voltage power supply unit capable of being connected to a voltage raising unit. The term “adaptable low voltage power supply unit” means that the values of a certain number of its operating parameters can be modified as a function of the type of voltage rise unit which it

is connected.

  The invention also relates to a high voltage generator device, composed of the combination of such a low voltage power supply unit and a

  voltage raising unit capable of delivering the desired high voltage.

  Finally, the invention relates to a voltage raising unit designed to be "recognized" by such a low voltage power supply unit, in order to

  to allow the implementation of the method.

  The invention finds its preferred field of application in the electrostatic spraying of liquid or pulverulent coating product. In an installation of this kind, which can be manual or automatic, the projection device is equipped with one or more electrodes brought to a high voltage,

  to create an electrostatic field between the sprayer and the object to be coated.

  Such an electrode is brought to a voltage of the order of a few tens of kilovolts. This voltage is supplied by a high voltage generator device which generally breaks down into two parts: a low (or medium) voltage power supply unit, generally installed at a fixed station and a voltage raising unit comprising in particular a well mounted known known as voltage multiplier with diodes and capacitors, commonly called "cascade". This voltage raising unit is integrated into the sprayer. Consequently, the two units are interconnected by a strand of electrical wires. In practice, it is from time to time necessary to unpair these units, sometimes to modify the operating conditions, sometimes to replace a faulty unit. In both cases, there is the problem of compatibility between the two units that are connected to each other. Indeed, the operating parameters such as the operating frequency (the energy between the low voltage power supply unit and the voltage raising unit is often transmitted by medium frequency alternating current) the maximum admissible current or even the nominal voltage or the maximum admissible voltage may differ from one voltage rise unit to another and, therefore, the low voltage power supply unit must

  be able to be adapted accordingly.

  It is conventional, for example, that delicate, tedious and error-prone adjustment operations must be carried out on the low-voltage power supply unit each time the voltage rise unit connected to it is changed. The operator then proceeds by identifying the type of voltage rise unit by its manufacturing references. It deduces the corresponding operating parameters and then proceeds to a complete adjustment of the unit

  low voltage power supply.

  It has also been proposed to supplement the low voltage power supply unit with an automatic recognition system of the type of voltage rise unit which is connected to it. More specifically, the low voltage power supply unit contains a processor and a memory in which several groups of operating parameters have been written, each group corresponding to a voltage rise unit duly known.

  listed and likely to be connected to the low voltage unit in question.

  To do this, each voltage rise unit of a given and identified type contains a resistance of corresponding predetermined value. When the voltage raising unit is connected to an adaptable low voltage power supply unit, this resistance is "measured" by a suitable processor or measurement circuit. The result of the measurement makes it possible to "know" which voltage rise unit has just been connected. The processor is programmed to read the corresponding adjustment parameters from the memory of the low-voltage unit and to control the adjustment of the adjustments. Such a system is for example described in the patent document published under the

  No. 2,724,786 belonging to the Applicant.

  This system has some limitations. First of all, if one wishes a good differentiation of the types of voltage rise unit likely to be identified, it is necessary to choose resistors sufficiently different so that the voltage drop across the resistance is really characteristic of the type of voltage rise unit. In practice, it is estimated that two voltage values must differ by at least 0.5 V; it is hardly possible to distinguish more than twenty distinct values representative of twenty

  different voltage elevation units.

  On the other hand, the memory must contain quite a large amount of information, namely all the operating and adjustment characteristics for all the voltage rise units listed. Despite this, due to the normal technical evolution of the material considered, it may happen, after a certain time, that a new voltage raising unit, of a recent type, is not identified in the low voltage power supply memory. This then results in a non-recognition of the voltage rise unit, the stopping of the installation and the emission of a message or an alarm. This malfunction is all the more regrettable since it does not in itself mean that the low voltage power supply unit is unable to supply the voltage rise unit under the required conditions, failure or incident arising a failure to identify the voltage rise unit. Updating low-voltage power supply units is a major problem when you consider that these units are spread across hundreds of production units located around the world

whole.

  On the other hand, even for a given type of voltage elevation unit, dispersions of important characteristics are noted, which results in a high scrap rate in manufacturing. The refused units are not strictly speaking defective, but they would require special adaptations (in particular the choice of operating frequency) to which

  the low voltage power supply unit cannot comply.

  The invention solves all these problems.

  The basic idea of the invention consists in memorizing a set of information representing intrinsic characteristics of said voltage rise unit therein, for example by integrating a read only memory therein and having this information read by a external processor (for example contained in the low voltage power supply unit) when

  the interconnection between the two units.

  More specifically, the invention relates to a method for automatically identifying the operating parameters of an adaptable low voltage power supply unit, parameters required for supplying a voltage raising unit connected to said unit. power supply, characterized in that a connection is established between a memory associated with said voltage raising unit and reading means located outside of it, said memory containing a set of information representing intrinsic characteristics of said voltage rise unit, in that this information is read and in that said parameters of

  operation of said low voltage power supply unit.

  Preferably, the aforementioned reading means is combined with a control processor of the low voltage power supply unit and it is used to control the settings of the operating parameters of the latter as a function of the information read in the voltage rise unit memory. This control processor can be associated with another memory, for example a reprogrammable read-only memory, located in the low voltage power supply unit so that, during a connection between the two units or at each power-up, the information located in the memory associated with the voltage rise unit is read and transferred to the memory located in the low voltage power supply unit. From this moment, the electrical connection which was used to connect the processor to the memory of the voltage rise unit can be assigned to another use. In particular, it is advantageous to place a temperature probe in the voltage raising unit to control its temperature throughout its operation. Excessive temperature can be an indication of malfunction and a hazardous situation. The processor can therefore be programmed to monitor the temperature development and trigger an alarm and / or interrupt operation if

  this temperature reaches a threshold considered dangerous.

  The invention also relates to a high-voltage generating device in particular for supplying an electrostatic headlamp with a coating product, of the type comprising a low-voltage, adaptable power supply unit and a voltage raising unit, the two units being connected by a strand of electric wires, characterized in that said voltage raising unit comprises a memory containing a set of information representing intrinsic characteristics thereof and in that it further comprises reading means of said memory, located outside said voltage raising unit and means for programming operating parameters of said low voltage power supply unit, said information being used as data by

said programming means.

  As for example a parameter such as the operating frequency and / or the amplitude of the low or medium voltage signal delivered by said low voltage power supply unit, it is possible to program the processor so that it controls the generator means for developing the voltage required by the voltage raising unit under the exact desirable frequency, as soon as the corresponding information is specifically available in the memory of the voltage raising unit. Of course, from the initial values communicated to it on reading from the memory, the process can be programmed to constantly adapt the operating frequency and / or the low voltage supply voltage in order to maintain the optimal operating conditions. , as described in document FR2 724 785 filed in the name of the Applicant. The invention also relates to a voltage raising unit as such, characterized in that it comprises a memory in which are written information representing intrinsic characteristics thereof, said memory being capable of being read when said voltage raising unit is connected to a power supply unit

  low voltage of the type described above.

  Of course, the invention also covers any device for spraying coating product by electrostatic means, equipped with an elevation unit.

  voltage according to the above definition.

  The invention will be better understood and other advantages thereof

  will appear more clearly in the light of the following description of a

  high voltage generator device in accordance with its principle and implementing the defined process, given only by way of example and with reference to the attached drawing in which: - the single figure is a block diagram of such a generator device

high tension.

  In the drawing, the essential elements of a high-voltage generating device 11 are shown, which is divided into two sub-assemblies, namely a low-voltage power supply unit 12 and a voltage raising unit 13 normally integrated in a device for electrostatic projection of the coating product, not shown. The two units are connected together by a strand 14 of electrically conductive wires. The unit 12 is generally located at a fixed station and comprises, connected in cascade, a rectifier 16, a DC-DC converter 17 and a DC-AC converter 18. The rectifier is intended to be connected to an AC distribution circuit. The DC-DC converter 17 is controlled by a processor or other voltage control circuit 19. The converter 17 supplies an adjustable DC voltage to the DC-AC converter 18. The processor 19 also controls the frequency of the oscillations delivered by this converter. continuous-alternating. The latter therefore delivers at its output medium frequency electrical oscillations, of the order of a few tens of kHz, under a low or medium voltage. This alternating signal is applied to the elevation unit of

tension by two strand wires 14.

  The voltage raising unit 13 notably comprises a step-up transformer 20 and a voltage multiplier circuit 27 of the type with capacitors and diodes, commonly called "cascade". The output of this voltage multiplier is connected to the high voltage output SHT of the generator, via a protective resistor R. The output of the DC-AC converter 18 located in the low-voltage power supply unit 12 is connected to the primary winding 21p of the step-up transformer 20. The secondary winding 21s of this same transformer 22 is connected to the voltage multiplier circuit 27. A measurement resistor R1 is connected between one end of the secondary winding 21s and the mass of the device. The resistor R1 is here located in the low voltage unit via a conductor 30 extending between the two units and forming part of the strand 14. If we consider that the assembly constituted by the secondary winding 21s and the voltage multiplier circuit 27 constitutes a high voltage generator dipole extending between ground and the SHT output. It appears that the current flowing towards the load connected to the SHT output is also the current which crosses the resistor R1. Consequently, the voltage which develops at the terminals of this resistor is representative of the high voltage current I. This voltage representative of the current I is "measured" permanently by the circuit 19 forming the control processor. The output of the voltage multiplier 27 is also connected to a conductor 32 via a measurement and discharge resistor R2. The voltage available between this conductor 32 and earth is therefore representative of the value of the high voltage U. The conductor 32 is part of the strand 14 and is connected to circuit 19. This circuit is, as we have seen, essentially a processor which notably controls the voltage delivered

  by converter 17 and the operating frequency of converter 18.

  This processor is connected to a memory M0 which can for example be of the reprogrammable read-only memory type. This memory is organized so as to be able to contain information representative, in particular, of the technical characteristics of the voltage raising unit which is actually connected to the low voltage power supply unit. The processor 19 is programmed to calculate and adjust the operating parameters of the low voltage power supply unit from the values it finds in the memory M0. It is also programmed to update the information contained in this memory. For example, an update can be organized each time the high voltage generator device is put into service. According to a remarkable characteristic of the invention, the voltage raising unit also contains a memory M, which can be a read-only memory containing a set of information representing intrinsic characteristics of the voltage raising unit in which it is located. This memory is connected by conductors 36 of the strand 14 to the processor 19. A temperature probe 38 also located in the voltage raising unit

  is connected to these same conductors of the strand 14.

  When the voltage raising unit 13 is manufactured, a series of information representing once and for all is written in the memory M1.

  intrinsic characteristics of said voltage raising unit.

  Some of these characteristics, such as the maximum nominal voltage and the maximum current are determined by the type of voltage rise unit (its reference). These are values defined by the manufacturer,

  generally limit values which must not be exceeded.

  Other characteristics depend not only on the type of voltage rise unit considered but also on the combination of the components which constitute it. One of these parameters is for example a resonant frequency of the circuit constituted by the transformer 20 and said "cascade" 27 which it is useful to know with precision as soon as the processor 19 is able to adapt the frequency of the converter 18 at this specific resonant frequency. Thus, one solves the problem of the dispersions of characteristics of a unit of rise in tension to the other belonging to the same category, which makes it possible to effectively put into service of units of rise in tension which would have been considered as not conform in

the past.

  During an initialization period, that is to say for example each time a high voltage generator device is put into service consisting of the two units 12, 13 connected by a strand 14 (that is ie more often than the voltage rise unit is changed) the processor 19 reads the information contained in the memory M1 and transfers it, if it is different, in the memory M0. Depending on the information contained in the memory M0, the processor can permanently adjust the operating parameters of the power supply unit which are required for optimal supply of

  the voltage rise unit connected to it.

  Outside this initialization period where the transfer of information takes place between the memories M1 and M0, the processor 19 is permanently connected to the temperature probe 38 located in the voltage rise unit. During the entire operation of the device, the processor 19 "monitors" the signal delivered by the probe. It is therefore able to inhibit the low voltage power supply unit or at least to order the production of an alarm signal in the event that the temperature exceeds a predetermined value considered to be abnormal. The probe 38 and the memory M1 are connected to the processor 19 by the same conductors 36 of the strand 14. It is indeed important to minimize the number of conductors disposed in this connecting strand. Of course, the probe 38 can be part of the microcircuit which integrates

memory M1.

  As mentioned previously, any voltage rise unit provided with a read-only memory in which at least some of its intrinsic characteristics are inscribed must be considered to be within the scope of the claimed invention, a fortiori if said unit is also provided with a probe

  temperature connected to the same conductors of the connecting strand.

Claims (10)

  1- Method for automatic identification of operating parameters of an adaptable low voltage power supply unit (12), parameters required for supplying a voltage raising unit (13) connected to said unit power supply, characterized in that a connection is established between a memory (M1) associated with said voltage rise unit and reading means (19) located outside of it, said memory containing a set of information representing intrinsic characteristics of said voltage rise unit, in that this information is read and in that one deduces said operating parameters of said power supply unit low voltage electric.   2- A method according to claim 1, characterized in that said reading means (19) comprising a control processor, it is used to control the settings of operating parameters of said low voltage power supply unit as a function said   information read from said memory.   3- Method according to claim 2, characterized in that one implements such a control processor (19) located in said unit   low voltage power supply.   4- A method according to claim 3, characterized in that, said control processor (19) being associated with another memory (MB) located in said low voltage power supply unit, the information located in the memory is read (Ml ) associated with said voltage rise unit and they are written to the memory (M0) located in said power supply unit low tension.   5- Method according to one of the preceding claims, characterized in that   that the aforementioned information stored is representative of a nominal and / or maximum voltage and / or a maximum current and / or a   optimal operating frequency.   6- High voltage generator device, in particular for supplying an electrostatic headlamp with a coating product, of the type comprising a low voltage electrical supply unit (12), adaptable and a voltage raising unit (13), the two units being connected by a strand of electric wires, characterized in that said voltage raising unit comprises a memory (M1) containing a set of information representing intrinsic characteristics thereof and in that it comprises in in addition to means for reading (19) of said memory, located outside of said voltage raising unit and means for programming operating parameters of said low voltage power supply unit, said information being used as given by said programming means.  7- Device according to claim 6, characterized in that said means for reading said memory and said programming means are   housed in said low voltage power supply unit (12).   8- Device according to claim 7, characterized in that said reading means and said programming means comprise a processor (19) connected to said memory of the voltage rise unit and associated with its own memory (M0) o said information may be transferred.   9- Device according to claim 8, characterized in that said voltage raising unit (13) further comprises a temperature probe (32) connected to the processor and in that the latter is programmed to monitor the signal delivered by said probe and inhibit said power supply unit in case of   abnormal temperature detection.   - Device according to claim 9, characterized in that said processor (19) and said probe (38) are functionally connected by the same conductors which establish the connection between said processor and the memory (Ml)   contained in said voltage raising unit.   11- Voltage elevation unit characterized in that it comprises a memory (M1) in which are written information representing intrinsic characteristics of said unit, said memory being capable of being read when said voltage elevation unit is connected to a   low voltage power supply unit.