FR2952246A1 - Method for avoiding parasite phenomenon resulting from leakage of electric current in electric two wires lighting installation, involves disconnecting auxiliary load in closing state of control switch - Google Patents

Abstract

The method involves detecting an opening or closing state of a control switch (1), and drifting leakage current in the opening state of the control switch. An auxiliary load (30) is passed, where the auxiliary load is mounted in parallel to a load (2). The auxiliary load is disconnected in the closing state of the control switch. An electronic switch (5) is connected to a threshold detector (4), where the switch is connected to a neutral conductor (N) and a cut phase (Phc). An independent claim is also included for a device for avoiding parasite phenomenon resulting from leakage of electric current in an installation.

Description

METHOD FOR PREVENTING ADVERSE RELIEF RELATED TO LEAKAGE IN NEUTRAL FREE ELECTRONIC SWITCHES, AND DEVICE FOR IMPLEMENTING THE METHOD The invention relates generally to the switching of electric charges, in particular in lighting installations. .

More specifically, the invention relates, according to a first aspect, to a method for preventing parasitic phenomena resulting from an electrical current leak in an installation comprising a two-terminal alternating voltage source, a neutral conductor, a conductor of Phase, a cut-off phase conductor, a leakage current control switch, and a two-terminal load, the first terminal of the source being connected to the first terminal of the load by the neutral conductor, the second terminal of the the source being connected to the second terminal of the load via the phase conductor, the control switch, and the cut phase conductor.

The disappearance of incandescent lamps in favor of 25 light sources with electronic ballasts reveals new problems.

This situation, which concerns in particular the case where the electric charge comprises a compact fluorescent lamp (known by the acronym "CFL"), a light-emitting diode (or "LED"), or a ballast fluorescent tube, results from the existence of a leakage current which, in an installation of the type previously defined, passes through the load and the control switch when the latter is in the open state.

In particular, this situation appears in the case where the switch is of the dimmer switch type or mechanical switch with parallel light, and where the load is of the CFL type or an electronic ballast discharge lamp.

In this case, the leakage current of the dimmer switch accumulates in the storage capacity of the electronic ballasts, and the voltage at the terminals of this capacitor increases to excite the light source.

This phenomenon, known to those skilled in the art under the name "ghost effect", results in a bright flicker detrimental to the comfort of the user.

This artefact also appears in the case where the switch is of the dimmer switch type and where the load includes a lamp type LED operating at 230V, the least leakage current having the effect of lighting at least partially the LEDs.

This situation appears again in the case where it is desired to control by radio, according to ZigBee technology, a dimmer switch, the consumption of the radio module then being such that it is impossible to envisage the use of an electrical installation comprising only a neutral conductor and a phase conductor.

Currently, this problem is not solved but simply bypassed using switches with a neutral terminal, which is usually very restrictive renovation. More generally, none of the known solutions to try to solve or circumvent this problem is completely satisfactory.

In this context, the present invention aims to provide means for avoiding parasitic phenomena resulting from an electrical current leak in two-wire installations.

To this end, the method of the invention, furthermore in accordance with the generic definition given in the preamble above, is essentially characterized in that it comprises the operations of detecting the open or closed state of the control switch, to derive the leakage current, in the open state of the control switch, through an auxiliary load connected in parallel with the load, and to disconnect the auxiliary load in the closed state of the control switch. In other words, the invention essentially proposes to derive the leakage current when the two-wire switch is open, and to take all the necessary measures to consume very little energy when the switch is closed. .

The invention also relates to a device for implementing the previously defined method, this method being characterized in that it comprises a circuit designed to be mounted in parallel on the load between the neutral conductor and the cut phase conductor and to fulfill at least the auxiliary charging function, and in that this circuit comprises at least one threshold detector mounted between the neutral and phase cut conductors and providing an output signal varying according to whether the voltage between these conductors is at most equal to or greater than a predetermined threshold, an electronic switch connected to the neutral and cut phase conductors, and a current limiter connected in series with the electronic switch, this electronic switch being connected to the threshold detector and adopting an open state or closed depending on whether the voltage between the neutral and phase cut conductors is greater than or equal to it threshold.

In a possible embodiment of the invention, the circuit further comprises a rectifying module having a first input terminal connected to the neutral conductor, a second input terminal connected to the cut phase conductor, and first and second output terminals delivering a DC voltage, the current limiter and the electronic switch being connected in series between the output terminals of the rectification module.

Preferably, the electronic switch essentially comprises a depletion MOSFET transistor. In this case, the threshold detector comprises, for example, a first input terminal connected to the first output terminal of the rectifying module, a second input terminal connected to the second input terminal of the rectifying module, and a second input terminal connected to the first output terminal of the rectifying module, and output terminal connected to the gate of the depletion MOSFET transistor.

The circuit may further comprise a first protection module connected between the neutral conductor and the cut phase conductor, provided with at least one intermediate terminal, and including at least one varistor connected between the intermediate terminal and the neutral conductor, the second input terminal of the rectifier module then being connected to said intermediate terminal.

Moreover, this circuit can also advantageously comprise a second protection module connected in parallel with the electronic switch.

Other characteristics and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended drawings, in which:

- Figure 1 is a general diagram of an installation using the device of the invention;

FIG. 2 is a block diagram of a device according to the invention; and

- Figure 3 is a structural diagram of a device according to the invention.

As previously announced, the invention relates in particular to a method for avoiding parasitic phenomena resulting from a leakage of electric current in an electrical installation as illustrated in FIG.

Such an installation comprises a source V of alternating voltage, a neutral conductor N, a phase conductor Ph, a cut phase conductor PhC, a control switch 1, and a load 2.

The source V, which is in practice constituted by the electricity distribution network, has a first terminal V1 connected to the first terminal 21 of the load 2 by the neutral conductor N, and a second terminal V2 connected to the second terminal 22 of the load 2 via the phase conductor Ph, the control switch 1, and the cut phase conductor PhC.

The control switch 1, whose function is to enable control of the supply of the load 2 from the voltage delivered by the source V, has by construction, even in its open state, a non-zero resistance responsible for the circulation of a leakage current.

Functionally, the control switch 1 can therefore be represented as an ideal switch 11, across which a leakage resistor 12 is connected.

As indicated above, the leakage current passing through the switch 1 produces undesirable effects that the invention aims to suppress.

To do this, the method of the invention comprises the operations of detecting the open or closed state of the control switch 1, to derive the leakage current, in the open state of the control switch 1, through an auxiliary load 30 connected in parallel with the load 2, and disconnecting the auxiliary load 30 in the closed state of the control switch 1.

The function of the auxiliary charge 30 is fulfilled by the circuit 3 illustrated in FIGS. 2 and 3, respectively in a functional form and in a structural form, this circuit being designed to be connected in parallel with the load 2 between the neutral conductor N. and the phased phase conductor PhC.

As shown in these figures, this circuit 3 comprises at least one threshold detector 4, an electronic switch 5, and a current limiter 6. In the preferred embodiment illustrated, the electronic switch 5 is constituted by a MOSFET transistor. depletion 5, and the circuit 3 further comprises a rectifying module 7. The threshold detector 4, which is connected between the neutral and N phase cut conductors PhC, provides an output signal S varying according to the voltage between these N and PhC conductors are at most equal to or greater than a predetermined threshold.

In other words, the function of the threshold detector is to detect the open or closed state of the control switch 1, the voltage between the N neutral conductors and the cut phase PhC being much higher in the case where the control switch 1 is closed only in the case where the switch 1 is open.

The threshold detector 4 has two input terminals 41 and 42 respectively connected to the output terminal 701 and to the input terminal 72 of the rectifying module 7, as well as an output terminal 40 delivering the output signal S and connected to the gate of the depletion MOSFET transistor 5.

More specifically, the circuit comprising the capacitor C1, the Zener diode D1, the diode D2, the resistor R1 and the capacitor C2 form a capacitive supply circuit.

When the peak value of the AC voltage delivered by the source V is greater than the threshold defined by the Zener diode D3, this capacitive supply circuit 20 supplies a negative voltage to the gate of the MOSFET transistor 5 and places this transistor in its blocking state. .

The electronic switch 5, which is connected to the N and cut phase PhC neutral conductors, is therefore controlled by the threshold detector 4 so as to adopt an open or closed state depending on whether the voltage between the neutral conductors N and The cut phase PhC is greater than or equal to the predetermined threshold set by the Zener diode D3 characteristic.

The current limiter 6 is connected in series with the electronic switch 5.

This limiter, which comprises, for example, a resistor R2 with a positive temperature coefficient in series with another resistor R3, has the function of limiting to an acceptable level the current in the transient MOSFET transistor 5 when this transistor is conducting, and particularly when the load 2 is turned on, or when a fault on the supply network V causes a drop in the AC supply voltage of the installation.

The rectifying module 7 has two input terminals 71 and 72 respectively connected to the neutral conductor N and the cut phase conductor PhC, and two output terminals 701 and 702 delivering a DC voltage, the current limiter 6 and the electronic switch 5 being connected in series between these output terminals 701 and 702.

Preferably, the circuit 3 further comprises an input protection module 8 connected between the neutral conductor N and the cut phase conductor PhC and provided with at least one intermediate terminal 80.

This protection module 8, which protects the rectifying module 7 against overvoltages, comprises at least one varistor 81 connected between the intermediate terminal 80 and the neutral conductor N, the input terminal 72 of the rectifying module 7 being connected to this intermediate terminal 80.

The circuit 3 may also advantageously comprise a second protection module 9, mounted in parallel on the electronic switch 5 and ensuring the protection of this electronic switch against overvoltages.

The operation of the previously described device can be analyzed according to the four phases below.

(1) The control switch 1 is open and the transistor 5 is closed. In this stationary state, the leakage resistor 12 of the control switch forms a divider bridge with the resistors R2 and R3. The voltage across the load 2 is much lower than the threshold of the Zener diode D3, which confirms the on state of the depletion MOSFET transistor. The auxiliary load 30 constituted by the circuit 3 is therefore equivalent to a low resistance which derives the leakage current.

(2) Control switch 1 is closed while transistor 5 is still closed.

In this transient state, the voltage across the load 2 becomes equal to the mains voltage delivered by the source V. The negative voltage at the gate of the MOSFET transistor 5 has not yet been established. This transistor, still passing temporarily, is traversed by a transient peak of current, notably attenuated by the current limiter 6. (3) The control switch 1 is closed while the transistor 5 is still closed.

In this stationary state, the voltage at the gate of the MOSFET transistor 5 is equal to the elbow voltage of the Zener diode D1. The MOSFET transistor 5 is thus blocked, and the circuit 3 is in the standby state. (4) The control switch 1 is open while the transistor 5 is still open.

In this transient state, the equivalent capacitance seen from the gate of the MOSFET transistor 5 discharges into the resistor R1. The MOSFET transistor 5 thus remains temporarily blocked. The leakage current then passes into the load 2, this fugitive phase remaining in practice invisible.

Claims (7)

REVENDICATIONS1. Method for preventing parasitic phenomena resulting from an electrical current leak in an installation comprising a source (V) of two-terminal AC voltage (V1, V2), a neutral conductor (N), a phase conductor (Ph) , a phase cut off conductor (PhC), a leakage current control switch (1), and a two-terminal load (2) (21, 22), the first terminal (V1) of the source (V) being connected to the first terminal (21) of the load (2) by the neutral conductor (N), the second terminal (V2) of the source (V) being connected to the second terminal (22) of the load (2) via the phase conductor (Ph), the control switch (1), and the cut phase conductor (PhC), characterized in that it comprises the operations of detecting the state open or closed control switch (1), to derive the leakage current, in the open state of the control switch (1), through a auxiliary load (30) connected in parallel with the load (2), and disconnecting the auxiliary load (30) in the closed state of the control switch (1). 2. Device for carrying out the method according to claim 1, characterized in that it comprises a circuit (3) designed to be mounted in parallel on the load (2) between the neutral conductor (N) and the conductor phase (PhC) and to fulfill at least the auxiliary charging function (30), and in that this circuit (3) comprises at least one threshold detector (4) mounted between the neutral conductors (N) and cut phase (PhC) and providing an output signal (S) varying according to whether the voltage between these conductors (N, PhC) is at most equal to or greater than a predetermined threshold, an electronic switch (5) connected to the neutral conductors ( N) and phase cut off (PhC), and a current limiter (6) connected in series with the electronic switch (5), this electronic switch (5) being connected to the threshold detector (4) and adopting an open state or closed depending on whether the voltage between neutral (N) and phase cut conductors e (PhC) is greater than or equal to said threshold. 3. Device according to claim 2, characterized in that the circuit (3) further comprises a rectifying module (7) having a first input terminal (71) connected to the neutral conductor (N), a second terminal d input (72) connected to the cut phase conductor (PhC), and first and second output terminals (701, 702) supplying a DC voltage, and in that the current limiter (6) and the electronic switch ( 5) are connected in series between the output terminals (701, 702) of the rectifying module (7). 4. Device according to any one of claims 2 and 3, characterized in that the electronic switch (5) essentially comprises a depletion MOSFET transistor (5). 5. Device according to claims 3 and 4, characterized in that the threshold detector (4) comprises a first input terminal (41) connected to the first output terminal (701) of the rectifying module (7), a second input terminal (42) connected to the second input terminal (72) of the rectifier module (7), and an output terminal (40) connected to the gate of the depletion MOSFET transistor (5). 6. Device according to any one of claims 2 and 5 combined with claim 3, characterized in that the circuit (3) further comprises a first protection module (8) connected between the neutral conductor (N) and the cut phase conductor (PhC) having at least one intermediate terminal (80), and including at least one varistor (81) connected between the intermediate terminal (80) and the neutral conductor (N), and in that the second input terminal (72) of the rectifying module (7) is connected to said intermediate terminal (80). 7. Device according to any one of claims 2 to 6, characterized in that the circuit (3) further comprises a second protection module (9) connected in parallel to the electronic switch (5).