EP2775803B1 - Electric fence electrifier - Google Patents

Description

Field of the invention

The present invention relates to the field of electric fence electricians.

A fence energizer operates on the principle of pulsed electrical discharges of several thousand volts, usually less than 1 ms duration and repetition frequency of the order of 1 Hz.

The peak intensity of the pulse reaches about ten amperes, but the effective intensity calculated over the repetition period remains below the ten mA.

The energizer supplies electrical pulses to the fence itself.

The power source is either the 230 V sector or a battery or battery. Mixed feeding devices exist. Battery-powered devices can be equipped with a photovoltaic generator or a wind turbine.

Electric fences are designed to avoid any danger to humans or animals by limiting the energy delivered during a discharge to a few tens of joules.

The current passes through a wire rope without an insulating envelope but away from the ground (the electrical ground in the system) thanks to poles insulated electrically from this wire. The slightest contact of an animal with the cable allows the electric current to be in contact with the earth via the body of the animal. This gives him an unpleasant electric shock that forces him to stop contact.

The animals recognize these devices and continue to be wary of the wires even if the power supply is cut off (especially if they were wet at their first contact). They are now educated but forget just as quickly as after a winter in the stable for example.

An international (IEC 60335-2-76) or European (EN 60335-2-76) safety standard defines the limiting characteristics of the output pulse of an energizer.

Furthermore, the IEC TS60479-1 whose ^4th edition was published in July 2005 states that the human body impedance values can reach values as low as 50 ohms and the standardization group of French national committee recommended that the energizers verify that the energy of the pulses does not exceed 5 joules and 20 amperes-peak over an impedance range of 50 to 500 ohms.

State of the art

The document WO 88/10059 discloses a method for generating pulses in an energizer whereby pulses are regularly sent at time intervals of the order of one second. A load control device is implemented to detect the load present in the fence wire. This device generates the sending of a pulse much larger than the pulses regularly sent as soon as the load exceeds a value determined as representing the fact that an animal touches the fence. Such a larger impulse is sent as long as the load exceeds the threshold value.

Also known in the state of the art electric fence energizer described in the patent PCT / NZ99 / 00212 . This prior art energizer comprises a circuit for modifying the current output as a function of the change in the detected electrical charge. This circuit comprises a microprocessor receiving a signal from a sensor providing information controlling storing and outputting energy from a set of capacitors.

The patent application is also known EP2356888 describing a method of operating an electric fence energizer, comprising the steps of storing energy in an energy storage element, and transferring energy from the energy storage element to an inductive element, the method being characterized by the steps of using a rectifying element to prevent the transfer of energy from the inductive element into a load on the output of the energizer while the energy transfer from the energy storage element to the inductive element takes place, and by releasing the energy held by the inductive element once an energy threshold of the inductive element is reached.

The patent application is also known WO2009013412 disclosing an electric fence energizer, having a measurement and control circuit having periodic measurement means, of sufficiently short period for the measurement to be repeated several times during the duration of the pulse, of at least one characteristic electrical parameter instantaneous impedance present at the terminals of said energizer, comparison means for comparing the measurement results of said at least one parameter with reference values and control means able, in case of deviation, between the measurement results and the reference values, likely to correspond to the arrival of a human body in contact with the fence, to instantly modify the characteristics of the current pulse so that it is safe for the human body.

We still know the French patent FR2914137 describing a method of controlling an electric fence energizer of any power, ensuring on each pulse emitted by the energizer that any human body that has come into contact with the electric fence since a recent pulse, is not likely to receive due to the current pulse, a dangerous electric shock.

• des moyens de détermination d'un risque de présence d'un corps humain en contact de ladite clôture électrique, ou l'absence d'un tel risque,
• des moyens de calcul de la proportion d'une impulsion susceptible de traverser un corps humain au contact de la clôture
• des moyens de bridage d'une impulsion.

This method provides:

• means for determining the risk of the presence of a human body in contact with the said electric fence, or the absence of such a risk,
• means for calculating the proportion of an impulse likely to pass through a human body in contact with the fence
• means for clamping a pulse.

Disadvantages of prior art

The solutions of the prior art have various disadvantages.

The process proposed by the patent FR2914137 involves the ability to determine the presence of a human body. However, such a determination is impossible in reality. Indeed, the indirect means such as the measurement of the electric charge do not make it possible to distinguish the presence of a human body, compared to other phenomena such as the presence of an animal or an object such as a tree branch or vegetation. Moreover, a human body does not have an electrical characteristic that is sufficiently reproducible and reliable to allow effective detection: a person wearing rubber boots, forming an electrical insulator, will have a very different electrical characteristic from a person moving on wet ground with wet and non-insulating shoes.

Moreover, the clamping does not make it possible to optimize the electrical consumption of the equipment.

Solution provided by the invention

In order to remedy these drawbacks, the invention relates, in its most general sense, to an electric fence energizer comprising a high-voltage pulse generator comprising an electrical transformer powered by a control circuit receiving a signal representative of the impedance of the line. closing device provided by a measuring coil and controlling the frequency and the energy of the pulses according to the impedance of the closing installation connected to the output of said transformer characterized in that said transformer comprises two primary coils connected in parallel and two secondary coils connected in series, said transformer further comprising a soft iron frame consisting of two magnetic circuits mechanically connected to each other, each of the circuits being surrounded by one of said primary coils and one of said secondary coils, one at least one of said circuits being further surrounded by by said measuring coil.

This transformer makes it possible to supply high voltages, typically of 15000 volts instead of 8000 volts, under conditions of supply and consumption comparable to those of the equipment of the prior art, and to deliver information for controlling the discharge circuit. able to comply with safety standards.

Advantageously, the signal delivered by said measuring coil is sampled, the digital signal then being compared with a table of concordance between the voltage and the predetermined impedance of the line, for controlling said control circuit.

According to a preferred embodiment, the result of said comparison controls the number of active capacitors for each of the pulses.

Preferably, the energizer according to the invention comprises a delay circuit associated with said circuit of control to control the number of active capacitors for each of the pulses.

According to an advantageous variant, it further comprises a capacitor connected in parallel to the output of the two secondary circuits in series, to form a resonant circuit.

Preferably, said capacitor has a capacitance of between 1 and 10 nanofarads.

Detailed description of a nonlimiting example of embodiment

• la figure 1 représente le schéma de principe de l'équipement
• la figure 2 représente une vue de la culasse magnétique du transformateur.

The invention will be better understood on reading the description which follows, referring to a nonlimiting exemplary embodiment illustrated by the accompanying drawings in which:

• the figure 1 represents the schematic diagram of the equipment
• the figure 2 represents a view of the magnetic yoke of the transformer.

General description of the electric power circuit

The figure 1 is a simplified schematic view of an electric fence energizer according to an embodiment of the invention.

• deux bobines primaires (2 ; 3) connectées en parallèles
• deux bobines secondaires (4, 5) connectées en série
• une bobine de mesure (par exemple formé par une seule boucle) (6) dont la sortie est reliée à un circuit électronique de contrôle.

The energizer comprises a transformer (1) comprising:

• two primary coils (2; 3) connected in parallel
• two secondary coils (4, 5) connected in series
• a measuring coil (for example formed by a single loop) (6) whose output is connected to an electronic control circuit.

The primary of the transformer (1) is connected on the one hand to the phase of a voltage source, for example the mains, or an accumulator or a battery and on the other hand to a set of capacitors (7 to 10) of increasing capacities each controlled by a thyristor respectively (11 to 14) and a diode respectively (15 to 18).

The selection of one of the capacitors determines the energy applied to the primary of the transformer.

The storage capacitors (7 to 10) connected in parallel are charged at a voltage of a few hundred volts, for example 700 volts. On control of the control circuit selecting one of the capacitors, the corresponding thyristor (11 to 14) is made conductive with a period of the order of one second. When a thyristor (11 to 14) is turned on, the corresponding capacitor discharges through the thyristor and the two primary coils (2, 3) of the transformer (1). This discharge generates in the two secondary coils (4, 5) of the transformer (1) a pulse whose amplitude is a few kilovolts, for example 15 kV. This impulse, applied to the electric fence produces in case of contact by an animal or a human a sensation clearly perceptible and unpleasant, but never lethal or even dangerous because of the limitation of the energy.

The output of the secondary circuit further comprises a capacitor (19) of a few nanofarad, for example 4.9 nanofarad, to form an LC resonant circuit.

The control circuit receives the signal delivered by the measuring coil (6) electromagnetically coupled with the yoke of the transformer (1).

This signal is sampled and then processed by a microprocessor comparing with the reference values recorded in a table determining the capacitor to be activated according to the result of the comparison between the signal delivered by the measurement coil (6) and the values recorded. in the table.

The figure 2 is a schematic view of the magnetic circuit of the transformer (1). It comprises a stack of sheets (21, 22) of soft iron cut into the shape of "E" to allow the winding of the primary coil respectively (2, 3) and secondary respectively (4, 5) around a central tooth respectively (23, 24). The yokes (21, 22) are closed by a piece of soft iron respectively (25, 26).

The two yokes (21, 22) are mechanically connected by a weld (27) or any equivalent connecting means. By separating the two magnetic circuits, the saturation effect of the sheets is reduced when the transformer is subjected to a high voltage.

Detailed description of the general operation

• Un système de mesure de l'impédance caractéristique de ligne de clôture,
• un dispositif d'analyse et de commande, une dispositif de puissance et
• un dispositif de transformation en haute tension.

The energizer according to this nonlimiting example makes it possible to propose an intelligent Ultra Low Impedance (UBI) system capable of adjusting a power level on the closing line according to the impedance thereof, comprising:

• A system for measuring the characteristic impedance of the closing line,
• an analysis and control device, a power device and
• a high voltage transformer device.

The operation uses a programmable peak to ensure the management of the entire operation of the energizer, in compliance with the rules imposed by standard EN NF 60335-2-76 and its amendments A11 and A12 of March 2010.

The closing energizer is composed of four distinct parts that interact to periodically calculate the precise impedance of the fence line, to determine the amount of energy required to be sent online, based on this impedance allowing ensure full compliance with Amendment A12 of EN 60335-2-76. All data encrypted in terms of energy and time, frequency etc ... are indicative and adapt by simple correction in an assembly type program to the full respect of the said standard NF EN 60335-2-76 A11 + A12.

The first part has a power supply circuit that draws its energy from the 230 V 50 Hz distribution network, this circuit composed of various protection devices, aimed at protecting the rest of the electronics, but also to ensure that the charge voltage of the different capacitors that will be used in the power circuit will not go beyond a maximum value because of a momentary or recurring overvoltage of the said network, in order to limit any additional energy at the moment of the discharge of these said capacities responsible for the quantity of energy sent on the closing line (expressed in Joules).

These clipping devices may comprise zinc oxide varistors, and / or "Transil" type diodes, preceded by fast fuses in order to automatically cut off all the devices of the fence energizer, powered via this first part of the device. circuit, as soon as an overvoltage start occurs. A few nanoseconds will suffice to stop momentarily or permanently all or part of the supply voltage. This first part also supplies the corrected and filtered direct current type voltages necessary for the operation of the analysis systems, control card piloting.

The second so-called control portion is composed of a measurement circuit: A first low energy pulse is sent online by the microcontroller via a control device which empties a small capacitor into the transformer described below. A sample of the voltage at the two secondary of a special transformer composed of a specific mechanical assembly of two identical transformers with windings mounted in series for the secondary, and in parallel for the primary; is rectified, clipped if its value is greater than 150 Vdc then filtered and sent to an operational amplifier system (AOP). This AOP has a primary role that is to amplify the signal so that it is electrically exploitable, then send a so-called low voltage (LV) part to a first analog input of a microcontroller to calculate (by a table of correspondence that has been predetermined by laboratory measurements); (analog / digital conversion) the precise impedance of the fence line to determine the maximum amount of energy that will need to be sent, ensuring a maximum level of safety, as well as driving the Alarm LED and its audible signal. delay effect. Then send another part called High Voltage (HT) to a second analog input of said microcontroller, to calculate via a mathematical conversion formula (another form of analog / digital conversion) to give rise to the display of various information in the form of LEDS, maximum output voltage at instant T, value of the impedance of the line on LCD screen.

The microcontroller, knowing the very precise value of the impedance of the closing line, will be able to determine, (after different periods of delay in correspondence with what the standard EN 60335-2-76 A12 imposes) the quantity of energy that it will be possible to send (via the power section and its transformer described below by activating again one or more control device based on triacs or thyristors).

Details on BT and HT

While the amplitude of the signal (from 0 Ohms to a maximum value) being very large, between the minimum value of said signal, and its maximum, it was therefore created a so-called low voltage (LV) amplification, easily exploitable and very accurate for a line impedance of between 0 and 500 ohms for the "penalty energy on the fence line" portion, and so-called high-voltage (HT) amplification requiring less precision, but useful up to 15,000 volts at vacuum with an impedance higher than 1200 Ohms, intended for the "information display" part.

At an impedance value greater than 1200 Ohms, the LV circuit is already saturated, but this is not a problem, since there is no energy adaptation above 500 ohms. Thus, by exploiting this signal BT (0 to 500 Ohms) and this signal HT (up to more than 1200 Ohms), one creates an appropriate scale of measurement, giving the maximum of precision as for the value of real impedance of the fence line, rather than having a single measurement voltage that "sweeps" the entire impedance range from 0 ohms to greater than 1200 ohms, with less accuracy. This is the principle of the scaling of any measurement system, where it is advisable to always choose the scale of which 98% of the latter will be exploited when one reaches the maximum of the values to be interpreted.

In each of the circuits called AOP, these HV and LV signals are adjustable using variable resistive elements in order to compensate for the permissible error percentage of each transformer (plus or minus 10%). These two signals will be adjusted by varying a resistive element in order to adapt them as accurately as possible during the assembly of the measurement system with the specific transformer, which will compose the final fence energizer. Thus each measuring circuit is adapted to its respective specific transformer, regardless of its tolerance, thus increasing the accuracy of the values measured at a very high rate. (Adaptation of scale and adjustment to the specific transformer).

This microcontroller, before any measurement interpretation, send a virtual signal called "pulse test" without going through the "power", in order to perform a survey on both the LV channel and the HT channel, to ensure that the measuring circuit is not cut, and works well. In the case of a favorable result, the microcontroller will accept to take measurements into account, then convert them to digital format and continue the normal operation of the fence energizer with a managed output energy and meeting the standard in force. In the case of an unfavorable result, it will limit itself to sending the information to the energy limiting power circuit at 3 Joules. A kind of "minimum service" to electrify the fence wire and try to keep the animals, but with a quantity of energy well below the limit allowed by this standard, can not interpret measures to calculate the real impedance of the closing line (in case the measuring circuit is out of service, wire cut, AOP destroyed or no longer giving the right values). The microcontroller, will display the word "FAILURE RETURN 5AV" on the screen. control.

The microcontroller ( μ C) not only scans the impedance of the fence line, but then manages the amount of energy to be sent online via a more or less long delay, framed by the standard EN 60335-2-76 + A11 + A12. Measurement and punishment are done in a very short time, which corresponds to a pulse less than 10ms and the frequency of 0.58Hz.

Example 1

If the impedance of the determined closing line drops rapidly from> 1200 Ohms to less than 400 Ohms, the time of a pulse, and that it lasts the time indicated in the reference standard, the alarm starts sound, a light called "DELAY EFFECT" lights, and the device sends energy 1 pulse to 3. It is a "security" mode imposed. It lasts 10 minutes. Beyond the energizer resumes a normal mode of operation.

Example 2

When the microcontroller sees the closing line impedance change and fall below 500 Ohms, it adapts the amount of energy to be sent after a certain number of pulses determined by the said standard (minimum 15 pulses) and goes to the higher power level. If this is enough, the μ C will continue to control the power section to send this same level of energy until the next impedance change of the fence line. It will again take this regulatory time of at least 15 seconds before switching to the next level of energy. The fence energizer can have as many energy levels as desired without ever exceeding the energy values listed in the table given by the said standard relating to the amount of energy compared to the impedance of the closing line. In case the energy increase of one level is not enough, and it is possible to increase one more level immediately, because the impedance of the closing line has dropped, there is a time called "time "adaptation" by the said standard, which is a minimum of 5 pulses will be necessary before a new increase in energy output of the fence energizer. The increase in power is therefore in successive stages of 5 pulses between each, unless at a given moment the plateau has been reached, in which case it takes a minimum of 15 seconds before power change. These times allow any animal to entangle in a wire, give it time to leave before it is considered a permanent defect, and increase energy on the electric fence line.

Example 3

If suddenly a fault disappears, the line impedance is immediately changed, the μ C recalculates the impedance of the said fence line and allows to immediately return without delay, directly to the lower power level maximum imposed by the said standard to this impedance value.

Example 4: If no more faults are present, the impedance will be greater than 1200 Ohms, the fence energizer will be limited to 5 Joules without any delay. The ramp up is done in stages, but the power reduction in line is immediately at the next pulse as imposed by the said standard.

Thus it is certain that any person or animal coming to touch the electric fence line never receives more than 5 joule of energy regardless of the impedance of the said fence line. This operation also falls within what the said standard imposes by its amendment 12.

To increase the level of security of the fence energizer, other functions have been entrusted to the microcontroller: among others the latter ensures that all the capacitors used in the fence energizer are well charged to the correct value. The surveillance is done by opto-coupling. These opto-couplers also inform the μ C that all the capacitors that must be discharged to give the required energy level, are well. In the event of an anomaly of one of the two preceding criteria, the μ C decides to put the energizer on standby, in order to avoid the charge of capacitors possibly in short circuit causing an unusual overheating of the resistive elements of the circuit. load (power resistors) as well as bad energy levels by the simultaneous switching of two control devices, by mistake or spurious effect that can accidentally increase to an abnormally high energy level. This is an additional security point that the standard ignores. Power supply circuit power failure is via a relay directly controlled by the microcontroller, which negates the load of all capacitors and stops the operation of the device. The energizer therefore has a maximum level of security. A message inviting you to contact the after-sales service is displayed on an LDD screen.

A watchdog system is provided at the microcontroller to make a kind of automatic restart (BOOT) in case of crash of the microcontroller program. Any inconsistency switches the set to those security levels that sometimes go to the point of system shutdown. But this defect may be accidental or occasional; then there is an automatic restart system (BOOT) that starts the program at the starting point (minimum energy value at the closing energizer). The restart is done three times to follow if the fault is still present. After three times, it is considered that the defect is redundant, and that a service intervention is necessary.

The microcontroller is also requested to make a self-test diagnosis. Just remove a specific jumper for it to go into mode debugging. This mode makes it possible to know the digitized values in the digital analog conversion table. Thus it is easy to know the state and the stability of the measuring circuit. This allows to know where the program has planted to better understand the failures of the microcontroller or the power card, since all its operation is relayed to the microcontroller via these opto-couplers. Debug mode is a troubleshooting aid. Some characters are in Hexadecimal code in order to limit the number of digits and to display a maximum of information. This debugging portion is reserved for savvy people or technicians who wish to troubleshoot the entire fence energizer.

The third so-called power part is completely controlled by the control part described above, via opto-coupling systems for reasons of galvanic isolation between the low voltage of the control circuits such as the microcontroller and the triggers of the devices. switching devices such as thyristors or triacs. This power section is composed of capacitors of different values, or the combination of one or two, or more or all of the capacitive elements allow to obtain different energy levels sent to the specific transformer with a maximum of 15 Joules under 50 Ohms . The charge of the various capacitive elements is ensured by diodes of recovery in full alternation as well as by a series capacitor allowing an isolation vis-à-vis the network of distribution. This makes it possible to obtain voltages of approximately 650Vdc from the nominal 230Vac of the distribution network. The other diodes prevent the capacitors from being discharged simultaneously. Thus each capacitor to its control circuit and it can in no case be emptied into the specific transformer via another switching device such as triac or thyristor.

The fourth part called transformer (1) specific is composed of two transformers themselves composed of a primary winding (2; 3) and a secondary winding (6; 7). The primary winding is composed of stranded wires to withstand without damage and with a very low ohmic resistance the strong currents sent by the different capacitors and their associations between them.

The primary windings (2, 3) of the two transformers are connected in parallel. The secondary windings (6, 7) being 2, their voltage added, the section of their copper has been voluntarily increased compared to a lambda energizer ensuring a very low impedance at the transformer outputs. Hence the name of Ultra Low Impedance. The secondary windings of the two transformers are put in series so that the voltages are added. Each transformer is encapsulated with steel type EI 84 1W6, and are mechanically assembled next to each other to form a single magnetic circuit. The size of this circuit makes it possible to be able to transfer the energy sent to the primaries in order to obtain energies of 15 Joules at 50 Ohms secondary, and to have a high voltage without any saturation. To increase this no-load voltage, a specific high-voltage capacitance of between 1 and 10 nF connected in parallel with the secondary circuits is used to make these so-called oscillating secondary circuits (resonance frequency) to obtain a output voltage of a minimum of 15 Kv.

A very chopped characteristic curve is recorded at the output side of the secondary windings of the transformer allowing an ionization of the ambient air giving a click sound during the production of sparks with a higher decibel rate than the closing energizers of the state of the technical. In case of contact a tetanization of the muscles sometimes in positive direction sometimes in negative direction gives a sensation of pain much more important than a single curve of a single alternation.

Claims (6)

1. An electric fence energizer comprising a high-voltage pulse generator containing an electrical transformer powered by a control circuit receiving a signal representative of the impedance of the fence line supplied by a measuring coil and controlling the frequency and energy of the pulses as a function of the impedance of the fence installation connected to the output of said transformer, characterized in that said transformer comprises two primary coils (2; 3) connected in parallel and two secondary coils (4; 5) connected in series, said transformer further comprising a soft iron casing consisting of two magnetic circuits mechanically connected to each other, each of said circuits being surrounded by one of said primary coils and one of said secondary coils, at least one of said circuits being further surrounded by said measuring coil.
2. Electric fence energizer according to claim 1, characterized in that the signal delivered by said measurement coil (6) is sampled, the digital signal then being compared with a table matching the voltage and the predetermined impedance of the line, for controlling said control circuit.
3. Electric fence energiser according to claim 2, characterized in that the result of said comparison controls the number of active capacitors (7; 8; 9; 10) for each of the pulses.
4. Electric fence energizer according to claim 2 or 3, characterized in that it comprises a timing circuit associated with said control circuit for controlling the number of active capacitors for each of the pulses.
5. Electric fence energizer according to any of the preceding claims, characterized in that it further comprises a capacitor (19) connected in parallel to the output of the two secondary circuits in series to form a resonant circuit.
6. Electric fence energizer according to claim 5, characterized in that said capacitor (19) has a capacity of between 1 and 10 nanofarad.

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