Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
  • H01H47/002—Monitoring or fail-safe circuits
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
  • H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
  • H01H47/223—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil adapted to be supplied by AC
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
  • H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
  • H01H47/32—Energising current supplied by semiconductor device
  • H01H47/325—Energising current supplied by semiconductor device by switching regulator
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
  • H01F2007/1888—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings using pulse width modulation

Definitions

• the present invention relates to an electric contactor and a method for controlling an electromagnetic coil of such a contactor.
• the electrical contactor comprises at least one base and a control module.
• the base comprises at least one pair of fixed contacts and, for each pair of fixed contacts, a movable contact between a closed position and an open position. More specifically, the fixed contacts are electrically connected to each other, when the movable contact is in the closed position, and electrically isolated from each other, when the movable contact is in the open position.
• the base also includes an electromagnetic coil capable of controlling the or each movable contact in the closed position or in the open position, and the coil is characterized by a control setpoint voltage.
• the control module comprises an electronic module for controlling the electromagnetic coil.
• a persistent issue in the field of electrical contactors is to operate the contactor with a wide and complete panel of supply voltages.
• This adaptation is more particularly necessary when controlling the or each movable contact in the closed position.
• the goal is to have a single coil regardless of the contactor supply voltage. For this, it is necessary that the control voltage of the coil is lower than the minimum supply voltage of the contactor.
• the object of the invention is therefore to propose an electric contactor which, when controlling the or each movable contact in closed position, makes it possible to reduce the differences in the operating time between a supply voltage of the contactor in 1 10V and a supply voltage of the contactor at 220V.
• the subject of the invention is an electrical contactor comprising at least one pair of fixed contacts and for each pair of fixed contacts a movable contact between a closed position and an open position, the fixed contacts being, in the closed position of the contact movable, electrically connected to each other via the movable contact, and being electrically isolated from each other in the open position of the movable contact, an electromagnetic coil adapted to control the or each movable contact in the closed position or in the open position, and a electronic module for controlling the electromagnetic coil, comprising a switch connected in series with the coil and a device for controlling the switch, the switch comprising two conduction electrodes and a control electrode, said control device comprising means for calculating a pulse width modulated signal and means for applying the calculated signal to the control electrode of the switch.
• the pulse width modulated signal has a cyclic ratio of variable value over time, during the control of the or each movable contact in the closed position.
• the electric contactor further comprises one or more of the following characteristics, taken separately or in any technically permissible combination:
• the electronic control module furthermore comprises a positive voltage generator, such as a rectifier connected to the switch and to the coil connected in series and able to supply a positive voltage to the switch and to the coil, while the control device comprises means for measuring the positive voltage, and the value of the duty cycle depends on said measured voltage;
• a positive voltage generator such as a rectifier connected to the switch and to the coil connected in series and able to supply a positive voltage to the switch and to the coil
• the control device comprises means for measuring the positive voltage, and the value of the duty cycle depends on said measured voltage
• the value of the duty cycle depends on said positive voltage measured only when controlling the or each movable contact in the closed position; the duty cycle is equal to the sum of a first term of constant value and of a second term of variable value over time;
• the first term is a function of a control voltage setpoint of the coil and the initial value of the positive voltage, measured at the time of the closing command of the or each movable contact;
• the second term is a function of the last measured value of the positive voltage
• the means for measuring the voltage are suitable for sampling the positive voltage measured according to a sampling frequency, whereas the calculation means are capable of calculating the second term as a function of the last positive voltage sample and according to a calculation period; equal to the inverse of the sampling frequency, and the calculation means are able to update the value of the duty cycle, using the second term, at each calculation period.
• the invention also relates to a method for controlling an electromagnetic coil of a contactor, which contactor comprises at least one pair of fixed contacts and, for each pair of fixed contacts, a movable contact between a closed position and a open position, the electromagnetic coil, and an electronic control module of the coil comprising a switch connected in series with the coil and a switch control device, the coil being able to control the or each movable contact in the closed or open position, the method comprising the following steps:
• the pulse width modulated signal is calculated with a cyclic ratio of variable value over time during the control of the or each movable contact in the closed position.
• the method of controlling the electromagnetic coil of the contactor further comprises one or more of the following characteristics, taken separately or in any technically acceptable combination:
• the method comprises the measurement of a positive voltage across a positive voltage generator, such as a rectifier, which rectifier is connected to the switch and to the coil connected in series, and is capable of supplying positive voltage to the switch and the coil, while in step a) the duty cycle of the modulated pulse width calculated signal depends on the positive voltage measured only when controlling the or each movable contact in the closed position;
• a positive voltage generator such as a rectifier, which rectifier is connected to the switch and to the coil connected in series, and is capable of supplying positive voltage to the switch and the coil
• step a) comprises several steps consisting of:
• step a3) calculating the duty cycle by summing the first term and the second term, and following step b) returning to step a2), as long as the or each movable contact is not in the closed position ;
• the first term is calculated as a function of a control voltage of the coil and of the initial value of the positive voltage, this initial value being measured at the time of the closing command of the or each moving contact, during the measurement step, and the duty cycle is set equal to this first term;
• the second term is calculated as a function of the last value of the measured positive voltage
• T2 G ⁇ (U A - (T) * U E (T)) dT
• ⁇ ( ⁇ ) and U e (T) respectively representing the values of the duty cycle and the positive voltage at time ⁇ and G a predetermined value gain
• step b the switch switches with a certain frequency according to the duty cycle and thus modifies the voltage across the coil.
• the complete closing of the moving contacts of the contactor is ensured, the closing time of the moving 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 as the duty cycle varies over time. More specifically, regulation in voltage takes into account possible voltage drops in the contactor. In addition, the regulation makes it possible to correct the voltage delivered to the coil in order to take into account the case where the instantaneous voltage applied to the coil and the switch connected in series is lower than the control setpoint voltage of the coil.
• FIG. 1 is a schematic representation of a contactor according to the invention, comprising a pair of fixed contacts, a movable contact adapted to open or close the electrical connection between the fixed contacts, an electromagnetic coil for controlling the movable contact and a coil control module, said module comprising a switch connected in series with the coil;
• FIG. 2 is a partial representation of a simplified electric circuit diagram of the contactor of FIG. 1;
• FIG. 3 is a block diagram showing means for calculating a duty cycle of a pulse width modulated signal intended to be applied to the switch of the contactor of FIG. 1;
• FIG. 4 is a flowchart of a method according to the invention for controlling the coil of FIG. 1;
• FIG. 5 is a set of two curves representing the current flowing through the coil of FIG. 1 as a function of time, during the closing command of the moving contact of FIG. 1, for a contactor supply voltage of 1 volts and respectively for a supply voltage of the contactor of 230 volts;
• FIG. 6 is a set of two curves representing the displacement of the moving contact of FIG. 1 as a function of time, during the closing command of the movable contact, for a supply voltage of the contactor of 1 15 volts, and respectively for a contactor supply voltage equal to 230 volts;
• FIG. 7 is a set of two curves, a first curve representing revolution of a duty cycle as a function of time, the duty cycle being specific to a pulse width modulated signal calculated by a control device included in the contactor. of Figure 1 and the second curve representing the voltage across the electromagnetic coil and the contactor switch of Figure 1 connected in series, as a function of time.
• a contactor 10 is shown.
• the contactor 10 comprises a base 12 and an electronic module 13 for driving an electromagnetic coil 14.
• This electromagnetic coil 14 is characterized by a control setpoint voltage U A.
• the base 12 comprises the electromagnetic coil 14, and 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, in the closed position of the movable contact 17, electrically connected to each other via the movable contact 17, and are electrically isolated from each other in the open position of the movable contact 17.
• Each fixed contact 16 is intended for be connected to an electrical connection cable.
• the base 12 comprises a connector 20 for connecting the electronic control module 13.
• the electronic control module 13 is intended to be powered by a power supply member 22 and comprises an electronic card 24.
• the electronic card 24 comprises a switch 26, a generator of a positive voltage, variable over time or continuous, such as a rectifier 27, a switch control device 26, and protection means 30, such as a parallel varistor and a limiting series resistor.
• the electromagnetic coil 14 is adapted to control each movable contact 17 in the closed position or in the open position.
• the power supply member 22 is capable of delivering a supply voltage U c for the electronic control module 13, as shown in FIG. 2.
• the supply voltage U c is, for example, equal to 48 volts, 1 10 volts, 220 volts or 400 volts, in direct or alternating current.
• the base 12 comprises the same electromagnetic coil 14 regardless of the supply voltage U c of the control module 13, while the control module 13 is different according to the supply voltage U c .
• the electronic control module 13 to be connected to the connector 20 is chosen as a function of the supply voltage U c .
• the control module 13 differs, between the different values of the supply voltage U c , in particular with regard to the rectifier 27.
• the switch 26 comprises two conduction electrodes and a control electrode which are not represented in the various figures. As can be seen in FIG. 2, the switch 26 is connected in series with the coil 14.
• the rectifier 27 is adapted to deliver a DC voltage U E across 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 full wave rectification.
• the control device 28 includes means 31 for calculating a pulse width modulated signal S1, and an electrical connection 32 with the switch 26 in order to apply the calculated signal S1 to the switch 26, and more specifically to the switch control electrode 26, as shown in FIG.
• control device 28 comprises means 34 for measuring the positive voltage U E at the output of the rectifier 27.
• the measuring means 34 are connected at the output of the rectifier 27, whereas the means 30 are connected between the power supply member 22 and the rectifier 27.
• the calculation means 31 are suitable for calculating the pulse width modulated signal S1 with a variable duty cycle value a with time.
• the value of the duty cycle depends, for example, on the positive voltage U E.
• 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 summing these terms T1, T2 to obtain the duty cycle a.
• the cyclic ratio a pulse width modulated signal S1 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 U E at the output of the rectifier 27 is equal to the rms value measured by the measuring means 34, multiplied by a factor Z specific to the rectifier 27.
• the factor Z is equal to 0.9.
• the signal S1 is adapted to be applied to the control electrode of the switch 26 in order to control it.
• 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 duty cycle has determined, for a period of hashing of the switch 26, the percentage of time when the switch 26 will be closed, respectively open.
• the hash period is for example equal to 40us.
• the calculation means 31, represented in FIG. 3 in the form of a block diagram 80, comprise a divider 82, a multiplier 84, a comparator 86, an integrator 88 and an adder 90.
• the various calculations made make it possible to calculate the cyclical report a.
• Block diagram 80 depends on time and is equivalent to the following equation:
• the calculation means 31 are adapted to receive three input data 92, 94, 96.
• the first input data 92 corresponds to an initial voltage U E (0), initially measured at the output of the rectifier 27, that is, ie before the control of the movable contact 17 in the closed position.
• the second input data 94 corresponds to the control voltage U A for driving the coil 14, and the third input data 96 corresponds to an instantaneous voltage U E (x) measured across the rectifier 27.
• the instantaneous voltage U E (x) corresponds to the last value of the positive voltage measured by the measuring means 34.
• the divider 82 is able to receive as input the initial voltage U E (0) and the set voltage U A and to output the first term T1.
• the first term T1 is calculated by means of the divider 82 and is equal to the ratio of the driving instruction voltage U A to the initial voltage U E (0).
• the calculation equation of the first term T1 is written as follows:
• the duty cycle before the control of the movable contact 17 in the closed position is noted a (0) and is equal to the first term T1.
• the multiplier 84 is adapted to receive as input the last value of the instantaneous voltage U E (x) measured at the output of the rectifier 27 and the last calculated value of the duty cycle a, also called instantaneous duty cycle ⁇ ( ⁇ ).
• the data outputted from the multiplier 84 is equal to the instantaneous voltage U E (x) measured at the output of the rectifier 27, multiplied by the instantaneous duty cycle a (x).
• the output of the multiplier 84 is compared, with the aid of the comparator 86 connected at the output of the multiplier 84, with the reference voltage U A in order to obtain an error E (x).
• the error E (x) corresponds to the difference between, on the one hand, the target voltage U A and, on the other hand, the data outputted from the multiplier 84.
• This error E (x) is then integrated and multiplied by a gain G, using the integrator 88 connected at the output of the comparator 86.
• the integrator 88 is able to calculate the integral l (E (x)) of the errors E (x) computed from the beginning of the closing control of the movable contacts 17 and multiplies the integral 1 (E (x)) of the errors by the gain G in order to obtain the second term T2.
• the summator 90 is able to receive the first term T1 and the second term T2 at the input, the summator 90 being connected at the output of the divider 82, on the one hand, and at the output of the integrator 88, on the other hand .
• the summator 90 is then adapted to deliver in output the value of the duty cycle a by summing the first term T1 and the second term T2.
• the cyclic ratio is constantly changed over time. We denote a (t) the different values of the duty cycle a over time.
• the measuring means 34 of the positive voltage U E are suitable for sampling the positive voltage U E measured, with a sampling frequency Fech
• the second term T2 is a function of the last sample U E (k) of measured voltage.
• the second term T2 is calculated according to a calculation period P1 equal to the inverse of the sampling frequency F ECH of the measurement of the voltage.
• T2 (k) denotes the second discretized term according to the calculation period P1, and is a function of the last sample U E (k) of measured voltage. Knowing that k is a representative index of time and that this index is incremented by 1 at each calculation period P1.
• the index k is equal to 0 when sending the command of the movable contact 17 in the closed position, then is incremented by 1 at each calculation period P1 during the closing of the movable contact 17, and is reset to zero when the movable contact 17 is in the closed position.
• a (k) the cyclic ratio discretized according to the calculation period P1.
• the calculation period P1 is for example equal to 400 ⁇ s, and in the case where the hash period of the switch 26 is equal to 40 ⁇ s, this means that the duty cycle is updated every ten chopping periods.
• the second discretized term T2 (k) is calculated from a discretized error E (k) corresponding to the difference between, on the one hand, the target voltage U A and, on the other hand, the last sample U E ( k-1) measured voltage which is multiplied by the discretized duty cycle a (k-1), calculated at the previous calculation period P1.
• This discretized error E (k) is then integrated by performing the integral I (E (k)) of the discretized errors E (k) computed from the beginning of the closure control of the movable contacts 17 and the integral l (E ( k)) discretized errors E (k) is multiplied by a gain G in order to obtain the second discretized term T2 (k).
• the calculation means 31 are suitable for calculating the second discretized term T2 (k) and for updating the value of the discretized duty cycle a (k) for each calculation period P1, using the second discretized term T2. (k).
• the discretized duty cycle a (k) is equal to the sum of the first term T1 and the second discretized term T2 (k).
• the duty cycle a (0) of index 0 is equal to the first term T1.
• the equation of calculation of the discretized duty cycle a (k) is as follows: k
• a voltage control method of the coil 14 comprises different steps.
• a first step 102 consists of the calculation, by the control device 28, of the pulse width modulated signal S1 and of its duty ratio a.
• a second step 104 consists of applying the calculated signal S1, via the electrical connection 32, to the control electrode of the switch 26.
• a step 106 consists in measuring, via the measuring means 34, the initial voltage U E (0) at the output of the rectifier device 27, that is to say at the terminals of the switch 26 and the coil 14 connected in series, before the closing command of the movable contact 17.
• step 102 for calculating the signal S1 comprises, for example, the following steps:
• the measurement of the voltage U E is sampled as explained above and the second discretized term T2 (k) is calculated in a manner analogous to that explained above.
• the duty cycle a is calculated, during step 1 14, by summing the first term T1 and the second term T2.
• the second term T2 is discretized and the second discretized term T2 (k) is calculated for each calculation period P1 as explained above.
• the duty ratio a is updated at each calculation period P1.
• the discretized duty cycle a (k) calculated as explained above is obtained.
• step 104 the process returns to step 1 12 and is repeated until the closure of the movable contact 17 is detected.
• the method is repeated at each calculation period P1 until the closure of the movable contact 17 is detected.
• the cyclic ratio a is therefore variable over time, since it includes the second term T2 which is itself variable over time.
• the graph shows, on the ordinate, a current I E passing through the coil 14 expressed in Ampere (A), and in abscissa the time (t) expressed in seconds (s).
• a curve 120 represents the current I E passing through the coil 14 as a function of time (t), during the closing command of the movable contact 17 and with a supply voltage U c of the electronic control module equal to 1 15 volts.
• a second curve 122 is similar to the curve 120 but for a supply voltage Uc equal to 230 volts.
• the curves 120, 122 have generally the same shape and the delay between the curve 120 and the curve 122 is minimized according to the invention.
• the supply voltages are variable, sinusoidal and the gain G is equal to 3.
• the graph shows, on the ordinate, a displacement D in mm relative to the fixed contacts 16, and on the abscissa the time (t) in seconds (s).
• a third curve 124 represents the displacement of the moving contact 17 as a function of time, for a supply voltage U c of the electronic control module 13 of 1 15 volts
• a fourth curve 126 represents the displacement of the moving contact 17 as a function of the time, for a supply voltage U c of 230 volts.
• the curves 124 and 126 represent, more precisely, the displacement D as a function of time, during the control of the closing of the movable contact 17.
• the movable contact 17 is generally closed when the displacement reaches its maximum value; that is to say here for a displacement D of about 5 mm. It is observed that the difference in closing time between the curve 124 and the curve 126 is 5.4 milliseconds knowing that the closing time of the movable contact 17 is between 60 ms and 68 ms.
• the closing dynamics as a function of the supply voltage U c is substantially identical regardless of the supply voltage of the electronic control module 13 and the voltage regulation is performed.
• the evolution of the duty ratio a as a function of the time t in milliseconds (ms) is observed on a fifth curve 128, and on a sixth curve 130 the voltage U E at the output of the rectifier 27.
• Curve 130 shows a drop in voltage U E as a function of time t. This voltage drop is due to a temporary weakening of the supply member 22.
• the curve 128 shows that the duty cycle a is variable over time and evolves to take into account the drop in the voltage U E measured in output of the rectifier 27. Indeed, the duty cycle has increased to take into account the voltage drop and so that the switch 26, remains in the closed position longer, to provide the coil 14 the voltage sufficient to act on the closure of the mobile contact 17.
• the value of the duty cycle a is high, in order to supply the coil 14 with voltage for a sufficient duration.
• This increase of the duty cycle a makes it possible to accelerate the closing of the movable contact 17, in order to take into account the delay taken in closing the movable contact 17 due to the fact that the measured voltage U E was lower than the setpoint voltage U A .
• the delay is gradually caught up and the value of the duty cycle a gradually decreases.
• the objective is to have a cyclic ratio with an instantaneous value greater than the average value of this duty cycle a, during the closing phase of the movable contact 17, at the moment when the output voltage U E of the rectifier 27 becomes greater to the setpoint voltage U A , in order to correct the error.
• the evolution of the duty cycle over time avoids any risk of complete non-closure of the movable contact 17, knowing that this complete non-closure sometimes leads to the welding of the movable contact 17 on the fixed contacts. 16.
• the gain G is chosen so as to minimize the difference in the closing dynamics of the contactor 10 regardless of the supply voltage U c of the electronic control module 13.
• the contactor 10 comprises a filter connected in series with the coil 14 and the switch 26.
• the voltage U E measured at the output of the rectifier 27 is different from the voltage measured at the terminals. of the switch 26 and the coil 14 connected in series.
• the supply member 22 of the control module 13 is a single-phase voltage generator.
• a contactor comprising a control module 13 supplied with three-phase voltage, the rectifier 27 then being able to convert the three-phase voltage supplied by the supply member 22. a positive voltage delivered across the switch 26 and the coil 14 connected in series.

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• 2013
  • 2013-04-12 FR FR1353328A patent/FR3004581B1/fr active Active
• 2014
  • 2014-04-11 EP EP14716833.0A patent/EP2984671B1/de active Active
  • 2014-04-11 WO PCT/EP2014/057361 patent/WO2014167089A1/fr active Application Filing
  • 2014-04-11 ES ES14716833.0T patent/ES2637187T3/es active Active

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