Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/005—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection avoiding undesired transient conditions
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
  • H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device

Definitions

• the present invention relates generally to a safety device for an electrical system in a motor vehicle.
• the invention relates to an electrical system comprising a safety device intended to control a switch device allowing the dissipation of a discharge current generated by a parasitic inductance during the disconnection of electrical equipment from the device. electrical network of the motor vehicle.
• the safety device also makes it possible to filter electrical disturbances superimposed on the vehicle's electrical network so as to prevent any untimely triggering of the switch device.
• Electric or hybrid vehicles are equipped with an electrical power supply network supplying all the electrical equipment such as an alternator-starter or direct voltage converter, a switch device connected between the power source and electrical equipment so as to disconnect them from the electrical network.
• the connections between the various electrical equipment require long cable lengths, thus generating parasitic inductances and also overvoltages.
• a known problem is that of the dissipation of the electrical energy contained in the parasitic inductance during the disconnection of electrical equipment from the electrical network of the motor vehicle.
• Such an electrical system SE1 comprises a safety device 40 comprising:
• a main output terminal B intended to be connected to a first electronic device Ep1 and to a second electronic device Ep2,
• a switch device 100 comprising an input terminal E, an output terminal S and a control terminal G, the input terminal of the switch device 100 being connected to the main input terminal A, the terminal output of the switch device 100 being connected to the main output terminal B, said switch device 100 comprising at least a first switch Q1 and a second switch Q2, the control terminal G of said switch device 100 being connected to a control device 30 so as to open or close the first switch Q1 or the second switch Q2
• the safety device comprises a component for suppressing transient voltage (from the English "transient-voltage-suppressor" or TVS, such as a diode arranged to pass in reverse mode (avalanche mode) allows the excess current to be injected to the electrical ground so as to clip the switch voltage.
• TVS components have the problem of drifting in temperature and their dynamic resistance is not clear.
• the choice of TVS is very small and the power induced in these TVS is high.
• TVS components have a generally low impedance in order to limit an overvoltage during a high discharge current, these components also have a very high cost, while having a large bulk.
• the aim of the invention is to alleviate at least in part the aforementioned problems.
• an electrical system comprising a safety device comprising:
• a main output terminal intended to be connected to a first electronic device and to a second electronic device
• a switch device comprising an input terminal, an output terminal and a control terminal, the input terminal of the switch device being connected to the main input terminal, the output terminal of the control device switch being connected to the main output terminal, said switch device comprising at least a first switch, the control terminal of said switch device being connected to a control device so as to open or close the at least a first light switch
• said filter device controls the switch device in its linear area when the switch controller is inactive and when the parasitic inductance between the first and the second equipment is crossed by a discharge current.
• the safety device is remarkable in that the dissipation of the discharge current is achieved by the first and second switches using at least a part of the discharge current so as to control the first and second switches in the linear region.
• the switch device comprises: at.
• a first switch comprising:
• the filtering device comprises:
• the filter device further comprises a zener diode, the cathode of which is connected to the cathode of the fourth diode and the anode is connected to the control terminal of the switch device.
• the switches are MOSFET transistors, or IGBT transistors, or bipolar transistor
• the switch device comprises a first switch and a second switch
• the first switch comprising:
• the output terminal is connected to the output terminal of the second switch
• a control terminal is connected to the control terminal of the switch device.
• the second switch comprising: i. an input terminal connected to the output terminal,
• the output terminal is connected to the current output terminal of the first switch
• a control terminal is connected to the control terminal of the switch device.
• the filtering device further comprises:
• a diode bridge comprising:
• the filter device further comprises a second capacitor connected between the output terminal of the first switch and the control terminal of the switch device
• a resistor is connected between the control terminal of the switch device and the control device so as to separate the control voltage of the switch device from the voltage of the control device (30).
• the invention also aims, according to a second aspect, a voltage converter comprising a safety device according to a first aspect of the invention.
• the voltage converter is a DC-DC voltage converter or an AC-DC voltage converter
• the filtering device and the voltage converter according to the invention have in combination all or part of the aforementioned characteristics.
• FIG. 1 shows an electrical system comprising a safety device according to the prior art.
• FIG. 2 shows an electrical system comprising a safety device implementing the invention according to a first embodiment of the invention.
• FIG. 3 shows an electrical system comprising a safety device implementing the invention according to a second embodiment of the invention.
• the safety device 2 is for example integrated into an electrical network of a motor vehicle.
• the switch device 10 includes a switch Q1 being a MOSFET transistor.
• the SE2 electrical system comprising:
• a first electronic device Ep1 and a second electronic device Ep2 connected to a main output terminal B of a safety device 2.
• Safety device 2 comprising:
• a main input terminal A connected to a first DC voltage source BAT, for example a battery supplying a voltage of 48V.
• a switch device 10 comprising: 1.an input terminal E, connected to the main input terminal
• a control terminal G connected to a control device 30 via a resistor R iv. a filter device 20 connected between the current input terminal E and the control terminal G of the switch device 10; v. a switch control device 30 connected to the control terminal G of the switch device 10 via a resistor R
• the first and second equipment Ep1 and Ep2 are, for example, alternator-starter or voltage converter such as an inverter.
• the first item of equipment Ep1 is connected to the electrical ground and presents a voltage Vep1 between its terminals
• the second item of equipment Ep2 is connected to the electrical ground and has a voltage Vep2 between its terminals.
• the switch device 10 comprises a first switch Q1, the drain current input terminal of the first switch Q1 is connected to the input terminal E, the current output terminal s1 of the first switch Q1 is connected to output terminal S and control terminal g1 is connected to control terminal G.
• the control device 30 makes it possible to control the opening or closing of the first switch Q1.
• a current I which can flow in the direction of the input terminal E towards the output terminal S when the control device 30 controls the first switch Q1 on closing, no current not crossing the input terminal E to the output terminal S when the control device 30 controls the first switch Q1 on opening.
• the value of the resistor R connected between the control device 30 and the control terminal G is chosen so as to protect the control device 30.
• the value of the resistor R is furthermore chosen to direct the currents If and Ip to the control terminal G.
• the value of the resistance R is not zero and chosen so as to separate the voltage of the control device 30 from the control voltage of the switch device 10, said resistance value R is chosen preferably greater than 1 ohm, even more preferably greater than 10 ohms.
• the first and second electronic equipment Ep1 and Ep2 are supplied with electrical energy when the first switch Q1 is commanded to close by the control device 30.
• the state of the first switch Q1 being in a saturated state when 'it is commanded to close, and in the blocked state when the switch Q1 is commanded to open.
• the filtering device 20 comprises in the example considered:
• a first resistor R1 connected on the one hand to the current input terminal E and to the control terminal G of the switch device 10 via a fourth diode D4 and the zener diode DZ1.
• a first capacitor C1 connected in parallel with the first resistor R1.
• the fourth diode D4 is connected in series with the first resistor R1, the cathode being connected to the control terminal G via a zener diode DZ1. The anode being connected to the first resistor R1.
• a zener diode DZ1 whose cathode is connected to the cathode of diode D4, and its anode connected to the control terminal G.
• V d s V A - V B
• the filter circuit 20 then makes it possible to avoid an overvoltage when the first switch Q1 is opened and therefore to prevent the voltage between the output S and input E terminals from exceeding a predetermined threshold.
• the voltage between the output terminal S and the input terminal E is the switch voltage Vds of the first switch Q1.
• the impedance of the filter circuit 20 is then calculated so that a current If derived from the discharge current Id can flow through the filter circuit 20 when the impedance of the first switch Q1 increases.
• the current If being at least part of the discharge current Id making it possible to charge the first capacitor C1.
• the switch voltage Vds is applied to the first capacitor C1 allowing the charging of the first capacitor C1.
• the current flowing through the first capacitor C1 then feeds the control terminal G through the diode D4 and the zener diode DZ1 so as to maintain the first switch Q1 in an on state. Voltage at the terminals of the first capacitor C1 making it possible to maintain the control voltage Vgs of the first transistor Q1 in its linear region, thus preventing the control voltage Vgs from being zero.
• the first resistor R1 and the first capacitor C1 make it possible to filter low-frequency disturbances up to 1 kHz, preferably up to 10 kHz, so as to avoid a disturbance putting the switch Q1 back into conduction when 'it is controlled in an open state and when the electronic equipment Ep2 is inactive, the voltage Vep2 being substantially zero.
• the filtering device 20 makes it possible to control the control voltage Vgs of the first switch Q1 in its linear zone so as to cancel the discharge current supplied by the parasitic inductance L.
• the filtering device 20 makes it possible to control the first switch Q1 in its linear zone, when the control device 30 is inactive, in order to dissipate the discharge current Id by the first switch Q1, the dissipation of the discharge current occurring during the cancellation time being defined by [Math.3], the filtering device 20 being inactive when the first switch Q1 is controlled by the control device 30.
• the [Fig. 3] illustrates this second embodiment. For the sake of simplicity, identical references are given in this figure to the elements common with the first embodiment and illustrated in [FIG. 2]
• the SE3 electrical system comprises:
• Safety device 3 comprising:
• the switch device 100 comprises a first switch Q1 and a second switch Q2 connected "head-to-tail", in other words the first switch Q1 and the second switch Q2 are connected so-called "common source”.
• the first switch Q1 and the second switch Q2 are N doped MOSFETs.
• the current input terminal d1 of the first switch Q1 is connected to the input terminal E
• the current output terminal s1 of the first switch Q1 is connected to the current output terminal s2 of the second switch Q2 and the control terminal g1 is connected to the control terminal G
• the current input terminal d2 of the second switch Q2 is connected to the output terminal S
• the control terminal g2 is connected to the control terminal G.
• the filtering device (200) further comprises in the example considered: a.
• a diode bridge comprising:
• a zener diode DZ1 whose cathode is connected to the cathodes of diodes D1 and D4, and the anode is connected to the control terminal G.
• the control device 30 is able to control the opening or closing of the first switch Q1 and the second switch Q2.
• the current I is said to be positive when the DC voltage source BAT supplies the current I, the current I flowing through the switch device 100 in the direction of the input terminal E towards the output terminal S so as to supply the first Ep1 or the second Ep2 electronic equipment.
• the current I is said to be negative when the the first Ep1 or the second Ep2 electronic equipment supply the current I, the current I flowing through the switch device 100 in the direction of the output terminal S towards the input terminal E so as to supply the DC voltage source BAT.
• the resistor R is connected between the control terminal G of the switch device 100 and the control device 30, so as to separate the control voltage of the switch device 100 from the voltage of the control device 30.
• the parasitic inductance L When opening the first switch Q1 or the second switch Q2, the parasitic inductance L generates a discharge current Id and a voltage at its terminals, which has the effect of creating an overvoltage between the output terminal S and the input terminal E of the switch system 100. Indeed, the voltage Va - Vb is directly applied to the voltage between the input terminal E and the output terminal S.
• the filtering circuit 200 therefore makes it possible to limit an overvoltage during the opening of the first switch Q1 or of the second switch Q2 and therefore to control the overvoltage and ensure that the voltage between the output terminals S and d ' input E does not exceed a predetermined threshold.
• the impedance of the filter circuit 200 is then calculated so that the current If derived from the discharge current Id can flow through the filter device 200 as the impedance of the switch device 100 increases.
• the current If enables the capacitor C1 to be charged, correlatively the voltage between the input E and output S terminals is applied to the capacitor C1, allowing the capacitor C1 to be charged.
• the filter circuit 200 is further designed to conduct at least part of the discharge current Id to the control terminal G of the switch device 100.
• the third and fourth diodes D3 and D4 make it possible to conduct a current If being part of the discharge current Id, so as to supply the control terminal G of the switch device 100 through the zener diode DZ1.
• the first and second diodes D1 and D2 make it possible to conduct a current Ip being a part of the discharge current Id, and therefore to supply the control terminal G of the device d 'switch 100 through the zener diode DZ1.
• the discharge current Id when the discharge current Id is said to be positive, the current If makes it possible to supply current to the control terminal G and the voltage at the terminals of the capacitor C1 makes it possible to maintain the control voltage Vgs of the first switch Q1 in its linear zone, the discharge current Id therefore passing through the first switch Q1 and then passing through the intrinsic diode of the second switch Q2. And when the discharge current Id is said to be negative, the current Ip makes it possible to supply current to the control terminal G and the voltage at the terminals of the capacitor C2 makes it possible to maintain the control voltage Vgs of the second switch Q2 in its linear zone , the discharge current Id therefore passing through the second switch Q2 and then passing through the intrinsic diode of the first switch Q1.
• the filtering device 200 makes it possible to maintain a control voltage Vgs applied to the first switch Q1 and second switch Q2 depending on the direction of the positive or negative discharge current.
• the first switch Q1 or the second switch Q2 being controlled in the linear zone, the voltage between the input terminal E and the output terminal S decreases and therefore makes it possible to avoid an overvoltage when opening one of the switches Q1 or Q2.
• the filtering device 200 allows the control voltage Vgs of the first and second switches Q1 and Q2 to be slaved in the linear zone so as to cancel the discharge current generated by the parasitic inductance L, which the discharge current either said positive or negative.
• the filtering device 200 further comprises a second resistor R2 making it possible to keep the first and second switches Q1 and Q2 open when disconnection of the control device 30.
• the first resistor R1 with the first capacitor C1 and the second resistor R2 with the second capacitor C2 form a band-pass type filter as defined by [Math.8] defining the attenuation of the disturbances as a function of a frequency and guaranteeing non-re-conduction of the first and second switches Q1 and Q2 in a frequency range defined by the choice of the components of the first and second resistor R1 and R2 and of the first and second resistors C1 and C2.

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• Electronic Switches (AREA)
• Safety Devices In Control Systems (AREA)
• Inverter Devices (AREA)

Priority Applications (2)

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Publications (1)

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ID=69104473

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Citations (4)

Family Cites Families (2)

• 2019
  • 2019-05-16 FR FR1905149A patent/FR3096188B1/fr active Active
• 2020
  • 2020-05-12 EP EP20724838.6A patent/EP3970253A1/fr active Pending
  • 2020-05-12 CN CN202080036036.9A patent/CN113826293A/zh active Pending
  • 2020-05-12 WO PCT/EP2020/063226 patent/WO2020229490A1/fr active Application Filing

Patent Citations (4)

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