ES2637187T3 - Electrical contactor and control procedure of an electromagnetic coil in such a contactor - Google Patents

Abstract

Electrical contactor (10), comprising: - at least one pair of fixed contacts (16) and, for each pair of fixed contacts, a mobile contact (17) between a closed position and an open position, the contacts (16) being fixed, in the closed position of the mobile contact (17), electrically connected to each other through the mobile contact (17), and being electrically isolated from each other in the open position of the mobile contact (17), - a suitable electromagnetic coil (14) for sending the or each mobile contact (17) to the closed position or open position, - an electronic control module (13) of the electromagnetic coil (14), which includes a switch (26) connected in series to the coil (14) and a switch control device (28) (26), including the switch (26) two conduction electrodes and a control electrode, the electronic control module (13) further comprising a positive voltage generator, such as a rectifier (27), connected to the switch (26) and to the coil (14) connected in series and appropriate to provide a positive voltage (UE) to the switch (26) and to the coil (14), said control device (28) including means (31) for calculation of a signal (S1) modulated in pulse width and means (32) for applying the calculated signal to the switch control electrode (26), the signal (S1) modulated in pulse width presenting a cyclic ratio (α) ) of variable value over time during the control of the or of each mobile contact (17) in closed position, including the control device (28) a means (34) for measuring the positive voltage (UE), and characterized because the value of the cyclic ratio depends on said voltage (UE) measured only during the control of or of each mobile contact (17) in the closed position.

Description

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DESCRIPTION

Electric contactor and control procedure of an electromagnetic coil in such a contactor

The present invention relates to an electrical contactor and a method of controlling an electromagnetic coil of such a contactor.

The electrical contactor comprises at least one base and one control module. The base comprises at least one pair of fixed contacts and, for each pair of fixed contacts, a mobile contact between a closed position and an open position. More precisely, the fixed contacts are electrically connected to each other, when the mobile contact is in the closed position, and electrically isolated from each other, when the mobile contact is in the open position. The base also includes an electromagnetic coil suitable for sending the or each mobile contact to a closed position or an open position, and the coil is characterized by a control setpoint voltage. The control module comprises an electronic control module of the electromagnetic coil.

A persistent problem in the field of electrical contactors is to operate the contactor with a large and complete range of supply voltages. Thus, it is known to perform a voltage adaptation between the supply voltage of the contactor and the electromagnetic coil. This adaptation is more particularly necessary during the control of each or every mobile contact in closed position. The objective is to have a single coil whatever the supply voltage of the contactor. For this, it is necessary that the control setpoint voltage of the coil be lower than the minimum supply voltage of the contactor.

In the field of voltage regulation of an electric contactor, it is known that an electromagnetic coil of reduced control setpoint voltage, associated with an electronic control module fed with a high voltage, i.e. 240 volts, consumes a great current. US 2005/047052 A1 describes an electric contactor according to the preamble of claim 1. It is also known from US-A-5 914 850 to make a voltage adaptation between the supply voltage of the contactor and the electromagnetic coil, a from means of control of the electromagnetic coil. The electromagnetic coil control means are suitable for generating a signal intended to be applied to the contactor control electrode. A rectifier is also used in order to provide the coil with a positive voltage, and the regulation is effective only when the voltage at the output of the rectifier is greater than the control setpoint voltage of the coil. This implies that if the average value of the voltage applied to the coil is calculated when the voltage at the output of the rectifier is greater than the setpoint voltage of the coil, the same result is not obtained for a supply voltage of the contactor equal to 110 volts and for a supply voltage of the contactor equal to 220 volts. This implies, therefore, some differences in the operating time, that is, in the dynamics or closing time of each mobile contact.

The object of the invention is therefore to propose an electric contactor that, during the control of each or every mobile contact in a closed position, allows to reduce the differences in operating times between a supply voltage of the contactor by 110 V and the voltage of contactor supply in 220 V.

For this purpose, the object of the invention is an electrical contactor comprising at least one pair of fixed contacts and for each pair of fixed contacts a mobile contact between a closed position and an open position, the fixed contacts being in a closed contact position mobile, electrically connected to each other through the mobile contact, and being electrically isolated from each other in the open position of the mobile contact, an electromagnetic coil suitable for sending the or each mobile contact to a closed position or open position, and an electronic control module of the electromagnetic coil, which includes a switch connected in series with the coil and a switch control device, the switch including two conduction electrodes and a control electrode, said control device including means for calculating a signal modulated in pulse width and means for applying the calculated signal to the switch control electrode. According to the invention, the pulse width modulated signal has a dclic ratio of variable value over time, during the control of each or every mobile contact in closed position.

According to some advantageous aspects of the invention, the electric contactor further comprises one or more of the following features, taken in isolation or according to all technically permissible combinations:

- the electronic control module further comprises a positive voltage generator, such as a rectifier connected to the switch and the coil connected in series and suitable to provide a positive voltage to the switch and the coil, while the control device includes a means of measurement of the positive tension, and the value of the dclic relationship depends on said measured voltage;

- the value of the public relation depends on said positive voltage measured only during the control of each mobile contact or in closed position;

- the relationship is equal to the sum of a first term of constant value and a second term of variable value over time;

- the first term is a function of a coil control setpoint voltage and the initial value of the positive voltage, measured at the time of the closing command of each or every mobile contact;

- the second term is the function of the last the measured value of the positive voltage; Y

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- the voltage measurement means are suitable for sampling the positive voltage measured according to a sampling frequency, while the calculation means are suitable for calculating the second term based on the last positive voltage sample and according to a calculation period equal to the inverse of the sampling frequency, and the means of calculations are adequate to update the value of the ratio, with the help of the second term, in each calculation period.

A subject of the invention is also a method of controlling an electromagnetic coil of a contactor, a contactor comprising at least one pair of fixed contacts and, for each pair of fixed contacts, a mobile contact between a closed position and an open position, the electromagnetic coil, and an electronic coil control module comprising a switch connected in series with the coil and a switch control device, the coil being suitable for sending the or each mobile contact to a closed or open position, comprising the procedure the following stages:

a) calculate, by the control device, a pulse width modulated signal, and

b) apply the calculated signal to a switch control electrode. In accordance with the invention, during the calculation stage, the pulse width modulated signal is calculated with a dclic ratio of variable value over time during the control of each or every mobile contact in closed position.

According to some advantageous aspects of the invention, the method of controlling the electromagnetic coil of the contactor further comprises one or more of the following features, taken in isolation or according to all thermally acceptable combinations:

- prior to step a) the procedure comprises measuring a positive voltage, at the terminals of a positive voltage generator, such as a rectifier, rectifier that is connected to the switch and the coil connected in series, and is appropriate to provide the voltage positive to the commutator and to the coil, while in the course of stage a) the dclic ratio of the signal modulated in pulse width calculated depends on the positive voltage measured only during the control of or of each mobile contact in closed position;

- stage a) includes several stages consisting of:

a1) the calculation of a first term of constant value

a2) the calculation of a second term of variable value over time

a3) the calculation of the relationship by adding the first term and the second term, and then stage b) returns to stage a2), while the or each mobile contact is not in a closed position;

- in the course of step a1), the first term is calculated based on a coil control setpoint voltage and the initial value of the positive voltage, this initial value being measured at the time of closing command of the o of each mobile contact, in the course of the measurement stage, and the relationship is fixed equal to this first term;

- in the course of step a2), the second term is calculated based on the last value of the measured positive voltage;

- in the course of step a1) the first term is calculated using the following equation:

T1 = a (0) = Ua / Ue (0),

representing (0) an initial value of the relationship,

in the course of step a2) the second term is calculated with the following equation:

T2 = G} (UA - a (t) * UE (t)) dT,

0

representing (T) and Ue (t) respectively the values of the dclic ratio and the positive voltage at time t and G a predetermined value gain,

the dical ratio being calculated in the course of stage a3) with the following equation:

t

a (t) = a (0) + G J U - a (t) * UE (t)) dT = T1 + T2;

0

Y

- after step b), the switch commutes with a certain frequency depending on the electrical relationship and thereby modifies the voltage at the terminals of the coil.

Thanks to the invention, the complete closing of the mobile contacts of the contactor is ensured, the closing time of the mobile contacts is substantially constant regardless of the supply voltage of the contactor, and the voltage regulation takes into account changes in the different voltages in the contactor over time since the relationship is valid over time. More precisely, the voltage regulation takes into account any voltage coffee in the contactor. In addition, the regulation allows correcting the voltage supplied

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to the coil in order to take into account the case in which the instantaneous voltage applied to the coil and the switch connected in series is lower than the coil control setpoint voltage.

The invention will be better understood, and other advantages of this will arise in the light of the description given below, only by way of non-limiting example, and made with reference to the accompanying drawings in which:

- Figure 1 is a schematic representation of a contactor according to the invention, comprising a pair of fixed contacts, an appropriate mobile contact for opening or closing the electrical link between the fixed contacts, an electromagnetic coil for controlling the mobile contact and a coil control module, said module including a switch connected in series with the coil;

- Figure 2 is a partial representation of a simplified electrical scheme of the contactor of Figure 1;

- Figure 3 is a block diagram showing means for calculating a dclic ratio of a pulse width modulated signal intended to be applied to the switch of the contactor of Figure 1;

- Figure 4 is an organization chart of a method, according to the invention, of control of the coil of Figure 1;

- Figure 5 is a set of two curves representing a current through the coil of Figure 1 as a function of time, during the closing command of the mobile contact of Figure 1, for a supply voltage of the contactor of 115 volts and, respectively, for a supply voltage of the contactor of 230 volts;

- Figure 6 is a set of two curves representing the displacement of the mobile contact of Figure 1 as a function of time, during the closing command of the mobile contact, for a supply voltage of the contactor of 115 volts and, respectively, for a contactor supply voltage equal to 230 volts;

- Figure 7 is a set of two curves, a first curve representing the evolution of a dclic relation as a function of time, the dclic relation being appropriate for a pulse width modulated signal calculated by a control device comprised in the contactor of Figure 1 and the second curve representing the voltage at the terminals of the electromagnetic coil and the contactor switch of Figure 1 connected in series, as a function of time.

A contactor 10 is shown in Fig. 1. The contactor 10 comprises a base 12 and an electronic control module 13 of an electromagnetic coil 14. This electromagnetic coil 14 is characterized by a control setpoint voltage Ua.

The base 12 includes the electromagnetic coil 14, as well as at least one pair of fixed contacts 16 and, for each pair of fixed contacts 16, a contact 17, movable between a closed position and an open position. The fixed contacts 16 are electrically connected, in the closed position of the mobile contact 17, with each other through the mobile contact 17, and are electrically isolated from each other in the open position of the mobile contact 17. Each fixed contact 16 is intended to be connected to an electrical link cable. In addition, the base 12 comprises a connection connector 20 of the electronic control module 13.

The electronic control module 13 is intended to be fed by a feeding organ 22 and comprises an electronic card 24. The electronic card 24 comprises a switch 26, a generator of a positive or variable voltage in the course of time or continuous, such as a rectifier 27, a switching device 28 of the switch 26, and protection means 30, such as variance in parallel and a resistance in series of limitation.

The electromagnetic coil 14 is suitable for sending each mobile contact 17 towards a closed position or an open position.

The supply organ 22 is suitable for providing a supply voltage Uc of the electronic control module 13, as shown in Figure 2. The supply voltage Uc is equal, for example, to 48 volts, 110 volts, 220 volts or even 400 volts, in direct or alternating current. The base 12 comprises the same electromagnetic coil 14 whatever the supply voltage Uc of the control module 13, while the control module 13 is different according to the supply voltage Uc. In this way, the electronic control module 13 to be connected to the connector 20 is chosen according to the supply voltage Uc. The control module 13 differs, between the different values of the supply voltage Uc, particularly as regards the rectifier 27.

The switch 26 comprises two conduction electrodes and a control electrode that are not shown in the different figures. As visible in Figure 2, the switch 26 is connected in series with the coil 14.

The rectifier 27 is suitable for providing a continuous voltage Ue at the terminals of the assembly formed by the switch 26 and the coil 14 connected in series. The rectifier 27 is, for example, a diode bridge that performs a double wave rectification.

The control device 28 includes means 31 for calculating the pulse width modulated signal S1, and an electrical link 32 with the switch 26 in order to apply the calculated signal S1 to the switch 26, and more specifically the control electrode of switch 26, as shown in Figure 1.

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In addition, the control device 28 includes measuring means 34 of the positive voltage Ue at the output of the rectifier 27. As is visible in Figure 2, the measuring means 34 is connected to the output of the rectifier 27, while the protection means 30 are connected between the feeding organ 22 and the rectifier 27.

The calculation means 31 are suitable for calculating the signal S1 modulated in pulse width with a value of dical to variable ratio over time. The value of the dclic relationship depends, for example, on the positive tension Ue. The calculation means 31 are suitable for calculating a first term T1 of constant value and a second term T2 of variable value over time and to add these terms T1, T2 to obtain the dclic relation a. The dical ratio a of the signal S1 modulated in pulse width is then of variable value over time since it is equal to the sum of the first and second terms T1, T2.

The positive voltage Ue at the output of the rectifier 27 is equal to the effective value measured by the measuring means 34, multiplied by a factor Z proper to the rectifier 27. In the case of a double wave rectifier and no particular device at the output of the rectifier, the factor is equal to 0.9.

The signal S1 is suitable to be applied to the control electrode of the switch 26 in order to command it. Thus, when the signal S1 is in "the high state", the switch 26 is closed and the current passes through the coil 14, and when the signal S1 is in "the low state", the switch 26 is open and the current does not pass through the coil 14. The dclic ratio determines for a cut-off conduction period of the switch 26, the percentage of the time in which the switch 26 will be closed, respectively open. The shortened conduction period is for example equal to 40 ps.

The calculation means 31, represented in Figure 3 in the form of a block scheme 80, comprise a divider 82, a multiplier 84, a comparator 86, an integrator 88 and an adder 90. The different calculations made allow the relationship to be calculated. Tell a. Block scheme 80 depends on time and is equivalent to the following equation:

a (t) = a (0) + G J (UA - a (t) * UE (t)) dr (1)

0

The calculation means 31 are suitable for receiving three input data 92, 94, 96. The first input data 92 corresponds to the initial voltage Ue (0), initially measured at the output of the rectifier 27, that is to say before the control of the mobile contact 17 in the closed position. The second input data 94 corresponds to the control setpoint voltage Ua of the coil 14, and the third input data 96 corresponds to an instantaneous voltage Ue (t) measured at the terminals of the rectifier 27. The voltage Ue (t) instantaneously corresponds to the last value of the positive voltage measured by the measuring means 34.

The divider 82 is suitable for receiving at the input the initial voltage Ue (0) and the setpoint voltage Ua and to provide the first term T1 at the output. The first term T1 is calculated thanks to divider 82 and is equal to the ratio of the control setpoint Ua over the initial voltage Ue (0). The calculation equation of the first term T1 is written as follows:

T1 = Ua / Ue (0). (2)

On the other hand, the dclic relationship a, before the command of the mobile contact 17 at closed position, is indicated by a (0) and is equal to the first term T1.

The set 98 formed by the multiplier 84, the comparator 86 and the integrator 88, connected one after the others and in this order, allows the calculation of the second term T2. The multiplier 84 is suitable for receiving at the input the last value of the instantaneous voltage Ue (t) measured at the output of the rectifier 27 and the last calculated value of the dclic ratio a, also called the instantaneous dclic ratio a (T). The data provided at the output of the multiplier 84 is equal to the instantaneous voltage Ue (t) measured at the output of the rectifier 27, multiplied by the instantaneous dclic ratio a (T). Subsequently, the data at the output of the multiplier 84 is compared, using the comparator 86 connected to the output of the multiplier 84, with the setpoint voltage Ua in order to obtain an error E (t). The error E (t) corresponds to the difference between, on the one hand, the setpoint voltage Ua and, on the other hand, the data provided at the output of the multiplier 84. This error E (t) is then integrated and multiplied by a gain G with the help of the integrator 88 connected to the output of the comparator 86. The integrator 88 is suitable for calculating the integral I (E (t)) of the errors E (t) calculated from the start of the closing command of the contacts 17 and multiply the integral I (E (t)) of the errors by the gain G in order to obtain the second term T2.

Subsequently, the adder 90 is suitable for receiving at the input the first term T1 and the second term T2, the adder 90 being connected to the output of the divider 82, on the one hand, and to the output of the integrator 88, on the other hand. Adder 90 is then appropriate to provide the output of the dclic ratio a by the sum of the first term T1 and the second term T2. The relationship is constantly modified over time. The different values of the dical relation to over time are indicated by a (t).

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In the described embodiment example, during the implementation of the calculation means 31, the measurement means 34 of the positive Ue voltage are suitable for sampling the measured positive Ue voltage, with a sampling frequency Fmues, and the second term T2 is function of the last EU sample (k) of the measured voltage. In other words, the second term T2 is calculated according to a period P1 of calculation equal to the inverse of the frequency Fmues of sampling of the voltage measurement. The second discretized term is indicated by T2 (k) according to the period P1 of calculation, and function of the last sample UE (k) of the measured voltage. Knowing that k is a representative index of time and that this index is increased by 1 with each period P1 of calculation. The index k is equal to 0 during the sending of the control of the mobile contact 17 to closed position, then it is increased by 1 with each period P1 of calculation during the closing of the mobile contact 17, and is reset to zero when the mobile contact 17 is in closed position. In the same way, the discretized cyclic relationship is indicated by a (k) according to the period P1 of calculation. The calculation period P1 is for example equal to 400 ps, and in the case that the trimmed conduction period of the switch 26 is equal to 40 ps, this means that the dclic ratio is updated every ten periods of trimmed conduction.

The second discretized term T2 (k) is calculated from a discretized error E (k) corresponding to the difference between, on the one hand, the setpoint voltage Ua and, on the other hand, the last sample UE (k-1 ) of measured voltage that is multiplied by the discretized cyclic ratio a (k-1), calculated in the period P1 of the preceding calculation. This discretized error E (k) is then integrated by making the integral I (E (k)) of the discretized errors E (k) calculated from the beginning of the closing command of the mobile contacts 17 and the integral I (E (k) )) of discretized errors E (k) is multiplied by a gain G in order to obtain the second discretized term T2 (k). Thus, the means 31 for calculating are appropriate for calculating the second discretized term T2 (k) and for updating the value of the discretized cyclic relation to (k) with each period P1 of calculation, with the help of the second discretized term T2 (k) In fact, the discretized cmlic relation a (k) is equal to the sum of the first term T1 and the second discretized term T2 (k).

In addition, the dclic relation to (0) of index 0 is equal to the first term T1. The calculation equation of the discretized cyclic relation to (k) is presented as follows:

a (k) = a (0) + G * fd (UA -a (x) * UE (x)) (3)

What is equivalent to:

a (k) = a (0) + T2 (k) = T1 + T2 (k) (4)

Thus, a tension control procedure of the coil 14 comprises different stages. A first step 102 consists in the calculation, by the control device 28, of the signal S1 modulated in pulse width and of its dical ratio a. Subsequently, a second stage 104 consists in the application of the signal S1 calculated, by means of the electrical link 32, to the switching electrode of the switch 26.

As a complement, prior to the calculation step 102, a step 106 consists in measuring, through the measuring means 34, the initial voltage Ue (0) at the output of the rectifying device 27, that is to say on the terminals of the switch 26 and of the coil 14 connected in series, before the closing command of the mobile contact 17.

In addition, step 102 of calculation of signal S1 includes, for example, the following steps:

- a step 108 for calculating the first term T1 and in the course of which, the dical ratio a is set equal to the first term T1;

- a step 112 for calculating the second term T2 as a function of the last voltage value UE measured at the output of the rectifier. As a complement, the measure of the tension Ue is sampled as explained above and the second term T2 (k) discretized is calculated analogously to what has been explained above.

Following step 112 of calculating the second term T2, the dclic ratio is calculated during stage 114, adding the first term T1 and the second term T2. As a complement, the second term T2 is discretized and the second term T2 (k) discretized in each calculation period P1 is calculated as explained above. Subsequently, thanks to the calculation of the second term T2 (k) discretized, the relationship with each P1 calculation period is updated. The discretized (a) cyclic ratio calculated as explained above is obtained.

Finally, following step 104, the procedure returns to step 112 and is repeated until the closure of the mobile contact 17 is detected. As a complement, the procedure is repeated in each calculation period P1 until the closure of the mobile contact 17 is detected.

The relation dclica a is therefore variable in the course of time, since it includes the second term T2 which is in turn variable in the course of time.

In Figure 5, the graph shows, in ordinates, a current Ie that crosses the coil 14 expressed in amps (A), and in abscissa the time (t) expressed in seconds (s). A curve 120 represents the current Ie that crosses the

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coil 14 as a function of time (t), during the closing command of the mobile contact 17 and a supply voltage Uc of the electronic control module equal to 115 volts. A second curve 122 is analogous to curve 120 but for a supply voltage Uc equal to 230 volts. Curves 120, 122 have the same overall shape and the delay of curve 120 and curve 122 is minimized according to the invention. For this example, the supply voltages are variable, sinusoidal and the gain G is equal to 3. The fact that curves 120 and 122 are globally similar, that the delay of curve 120 and curve 122 is optimized and that the Differences in amplitude between the two curves 120, 122 are limited, allows the coil to provide the same energy globally and therefore have a substantially identical mobile contact closure time 17 whatever the supply voltage Uc. In effect, the current Ie provides the energy and force necessary for closing the mobile contact 17. In Figure 6, it appears that whatever the supply voltage Uc, the current consumption of the coil seen from the source is the same overall.

In addition, in figure 6, the graph shows, in ordinates, a displacement D in millimeters in relation to the fixed contacts 16, and in abscissa the time (t) in seconds (s). A third curve 124 represents the displacement of the mobile contact 17 as a function of time, for a supply voltage Uc of the electronic control module 13 of 115 volts, and a fourth curve 126 represents the displacement of the mobile contact 17 as a function of time, for a supply voltage Uc of 230 volts. Curves 124 and 126 represent, more precisely, the displacement D as a function of time, during the closing command of the mobile contact 17. Thus, the mobile contact 17 closes globally when the displacement reaches its maximum value, that is to say in this case for a displacement D of approximately 5 mm. It is observed that the difference in closing times between curve 124 and curve 126 is 5.4 milliseconds knowing that the closing time 17 of the mobile contact is between 60 ms and 68 ms. Thus, the closing dynamics as a function of the supply voltage Uc is substantially identical regardless of the supply voltage of the electronic control module 13 and the voltage regulation is carried out correctly.

In addition, in figure 7, the evolution of the dclic relation a as a function of time t in milliseconds (ms) is observed in a fifth curve 128, as well as in a sixth curve 130, the voltage Ue at the output of the rectifier 27, expressed in volts, as a function of time t expressed in milliseconds. Curve 130 shows a brown of tension Ue as a function of time t. This strain of tension is due to a temporary reduction of the feeding organ 22. Curve 128 shows that the dclic ratio a is variable over time and evolves in order to take into account the brownness of the voltage Ue measured at the output of the rectifier 27. In effect, the dclic ratio a increases in order if the tension layer is taken into account and in order for the switch 26 to remain in the closed position longer, to provide the coil 14 with sufficient tension to act on the closure of the mobile contact 17.

In addition, it is also observed that when the voltage Ue measured at the output of the rectifier 27 is less than the setpoint voltage Ua of the coil 14, the dclic ratio increases in order to take into account the time span during which the voltage applied to coil 14 has no effect, since it is lower than the setpoint voltage Ua. This increase in the dclic ratio corresponds to an accumulation of the error that is restored when the voltage Ue at the output of the rectifier 27 is greater than the setpoint voltage Ua.

Thus, at the moment when the measured positive voltage Ue becomes greater than the set voltage Ua, the value of the dclic ratio a is large, in order to feed the coil 14 in tension for a sufficient duration. This increase in the dclic ratio makes it possible to accelerate the closing of the mobile contact 17, in order to take into account the delay taken on the closing of the mobile contact 17 due to the fact that the measured voltage U was lower than the setpoint voltage Ua . Once the measured voltage Ue becomes greater than the setpoint voltage Ua, the delay is small of small compensation and the value of the dclic ratio decreases progressively. The objective is to have an instantaneous value of a dclic ratio greater than the average value of this dclic relation a, during the closing phase of the mobile contact 17, at the moment when the output voltage Ue of the rectifier 27 becomes greater than the voltage A setpoint, in order to correct the error.

On the other hand, the evolution of the dclic relationship a over time allows to avoid any risk of complete non-closure of the mobile contact 17, knowing that this complete non-closure sometimes leads to the welding of the mobile contact 17 on the fixed contacts 16 .

Furthermore, it is important to note that the gain G is chosen so as to minimize the deviation in the closing dynamics of the contactor 10 whatever the supply voltage Uc of the electronic control module 13.

As a variant, at the output of the rectifier 27, the contactor 10 comprises a filter connected in series with the coil 14 and the switch 26. In this case, the voltage Ue measured at the output of the rectifier 27 is different from the voltage measured in the terminals switch 26 and coil 14 connected in series.

The person skilled in the art will understand that the invention is applied analogously to a three-phase contactor comprising three pairs of fixed contacts and three mobile contacts, for three-phase current applications.

In the exemplary embodiment of Figures 1 to 2 described above, the power organ 22 of the control module 13 is a single-phase voltage generator. The person skilled in the art will of course understand that the invention also applies to a contactor that includes a control module 13 fed in three-phase voltage,

the rectifier 27 being then suitable for converting the three-phase voltage provided by the supply organ 22 into a positive voltage provided to the terminals of the switch 26 and of the coil 14 connected in series.

Claims (9)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 1. Electric contactor (10), comprising: - at least one pair of fixed contacts (16) and, for each pair of fixed contacts, a mobile contact (17) between a closed position and an open position, the contacts (16) being fixed, in the closed position of the mobile contact (17), electrically connected to each other through the mobile contact (17), and being electrically isolated from each other in the open position of the mobile contact (17), - an electromagnetic coil (14) suitable for sending the or each mobile contact (17) to the closed position or open position, - an electronic electromagnetic coil control module (13), which includes a switch (26) connected in series to the coil (14) and a switch control device (28) (26), including the switch (26) two conduction electrodes and a control electrode, the electronic control module (13) also comprising a positive voltage generator, such as a rectifier (27), connected to the switch (26) and to the coil (14) connected in series and appropriate to provide a positive voltage (Ue) to the switch (26) and to the coil (14), said control device (28) including means (31) for calculating a signal (S1) modulated in pulse width and means (32) for applying the calculated signal to the switch control electrode (26), presenting the signal (S1) pulse width modulated a ratio (a) of variable value over time during the control of the or of each mobile contact (17) in closed position, including the device (28) for controlling means ( 34) of measurement of the positive voltage (Ue), and characterized in that the value of the dclic ratio depends on said voltage (Ue) measured only during the control of or of each mobile contact (17) in closed position. 2. Contactor according to claim 1, characterized in that the ratio (a) is equal to the sum of a first term (T1) of constant value and a second term (T2) of variable value over time. 3. Contactor according to claim 2, characterized in that the first term (T1) is a function of a coil control voltage (Ua) and the initial value (Ue (0)) of the positive voltage (Ue), measured at the time of the closing command of each mobile contact. 4. Contactor according to claim 2 or 3, characterized in that the second term (T2) is a function of the last measured value of the positive voltage (Ue). 5. Contactor according to one of claims 2 to 4, characterized in that the voltage measuring means (34) are suitable for sampling the positive voltage (Ue) measured according to a sampling frequency (Fmues), because the calculation means are suitable for calculating the second term (T2) based on the last sample of positive voltage (Ue) and according to a period (P1) of calculation equal to the inverse of the sampling frequency (Fmues), and because the means (31) of calculations are suitable to update the value of the cyclic relationship (a), with the help of the second term (T2), in each period (P1) of calculation. 6. Control procedure of an electromagnetic coil of a contactor (10), contactor comprising at least one pair of fixed contacts (16) and, for each pair of fixed contacts (16), a mobile contact (17) between a closed position and an open position, the electromagnetic coil (14), and an electronic coil control module (13) comprising a switch (26) connected in series with the coil (14) and a device (28 ) of the switch control (26), the coil (14) being suitable for sending the or each mobile contact (17) to a closed or open position, the procedure comprising the following steps: a) calculate (102), by the control device (28), a signal (S1) modulated in pulse width, the signal (S1) modulated in pulse width being calculated with a cyclic ratio (a) of variable value in the course of time, during the control of the or of each contact (17) mobile to closed position, b) apply (104) the calculated signal (S1) to a switch control electrode (26), and prior to step a) the procedure comprising measuring (106) a positive voltage (Ue), on the terminals of a positive voltage generator, such as a rectifier (27), rectifier (27) that is connected to the switch (26) and to the coil (14) connected in series, and is suitable to provide the positive voltage (Ue) to the switch (26 ) and to the coil (14), and characterized in that during the course of stage a) the cyclic relation (a) of the signal (S1) modulated in pulse width calculated depends on the positive voltage (Ue) measured only during the control of each contact (17) mobile to closed position. 7. Method according to claim 6, characterized in that step a) includes several stages consisting of: a1) the calculation (108) of a first term (T1) of constant value a2) the calculation (112) of a second term (T2) of variable value over time a3) the calculation of the cyclic relationship (a) by adding the first term (T1) and the second term (T2), and because after stage b) it returns to stage a2), while the or each mobile contact (17) is not in a closed position. 8. Method according to claim 7, characterized in that during the course of step a1), the first term (T1) is calculated based on a coil control voltage (Ua) (14) and the initial value ( Ue (0)) of the 5 positive voltage (Ue), this initial value being measured at the time of the command of the closure of each mobile contact (17), during the measurement stage (106), and because the dical ratio (a) is set equal to this first term (T1). Method according to one of claims 7 to 8, characterized in that in the course of step a2), the second term (T2) is calculated based on the last value of the measured positive voltage (Ue). 10. Method according to claims 8 and 9, characterized in that during the course of step a1) Calculate the first term (T1) with the following equation: T1 = a (0) = Ua / Ue (0), representing (0) an initial value of the cyclic relationship (a), because in the course of stage a2) the second term (T2) is calculated with the following equation: t 15 T2 = Gj (U „-a (T) * UE (t)) dT, 0 representing (T) and Ue (t) respectively the values of the dclic ratio (a) and the positive voltage (Ue) at time t and G a predetermined value gain, and because in the course of stage a3) the dical relation (a) with the following equation is calculated: t a (t) = a (0) + G j (U „- a (t) * UE (t)) dT = T1 + T2 0 Method according to one of the claims 6 to 9, characterized in that then in step b), the commutator (26) commutes with a certain frequency depending on the dclic relationship (a) and modifies the voltage at the coil terminals (14).