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
  • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
  • H02H9/042—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage comprising means to limit the absorbed power or indicate damaged over-voltage protection device
• • 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
  • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
  • H02H9/025—Current limitation using field effect transistors

Definitions

• the invention relates to an overvoltage protection device comprising at least one input intended to be connected to a power supply network, at least one output intended to be connected to an electrical circuit to be protected, and connected overvoltage limiting means. between the inputs and the outputs to protect said electrical circuit against overvoltages that can be applied to the inputs.
• the invention also relates to an electronic circuit comprising such a protection device.
• the known overvoltage protection devices generally comprise components connected in parallel on lines to be protected in order to limit voltage pulses by absorbing a disturbance current.
• such components are varistors or gas dischargers that can absorb a very large amount of electrical energy.
• FIG. 1 shows an electronic circuit 1 comprising a protection device of the state of the art described in the patent application FR2795567.
• a first protection device 10 has inputs 11 intended to be connected to an electrical distribution network, and outputs 12 for connection to downstream electronic circuits.
• the circuits are a rectifier 13, a voltage regulator 14 and a converter 15.
• a second surge protection device 17 is arranged downstream of the rectifier to improve the voltage protection.
• the devices 10 and 17 comprise series resistors connected in series on the lines and varistors connected in parallel downstream of the resistors 18.
• the resistors 18 protect the varistors by limiting the power absorbed.
• the object of the invention is to provide a protection device that avoids the drawbacks of devices of the state of the art by providing effective protection and reduced energy dissipation, as well as an electronic circuit comprising such a protection device.
• the overvoltage limiting means comprise:
• bidirectional series electronic limiting means comprising at least two inputs / outputs, connected in series with at least one of said inputs, and leading to a low voltage drop when a circulating current is less than a current limiting value, and limiting said circulating current by increasing a voltage drop between said inputs / outputs, and
• the electronic serial limiting means comprise two series-connected field effect transistors having their reference electrodes connected to a central part, their output electrodes being connected between said inputs / outputs, and their control electrodes being connected to said central portion, said current limiting value being defined by a control voltage threshold between the control electrodes and the respective reference electrodes and internal resistors of the transistors.
• the series limitation electronic means comprise at their central portion limiting resistance resistors connected in series with said reference electrodes, said current limiting value being also defined with values of said adjustment resistors.
• the series limiting electronic means comprise diodes for protecting the junctions of said field effect series limiting transistors connected in parallel with said limiting adjustment resistors.
• the series limiting electronic means have a series limiting voltage defined by an avalanche voltage or a breakdown voltage between the output electrodes and the respective reference electrodes of said series limiting transistors.
• the series-limiting electronic means comprise first avalanche-type diodes connected between the reference electrodes and the output electrodes of each transistor to allow the direct circulation of the circulating current in one direction and to limit a voltage on the transistors to a current. avalanche voltage in an opposite direction, said avalanche voltage of said first avalanche type diodes being less than a breakdown voltage of said transistors, said series limiting voltage being defined by avalanche voltages of said first avalanche diodes.
• the overvoltage limiting means comprise at least two series-connected electronic limitation means connected in series.
• the overvoltage limiting means comprise at least electronic series limiting means connected in series with each of the inputs.
• the electronic means of limitation series limit to a limiting voltage greater than 1000 volts.
• the electronic series limiting means comprise transistors supporting a voltage greater than or equal to a limiting voltage greater than 1000 volts.
• the series-limiting electronic means comprise field-effect transistors having an on-state series resistance of less than 10 ohms.
• the series limiting electronic means comprise silicon carbide field effect transistors.
• the parallel limitation of electronic means comprise at least one diode in avalanche effect connected at the output of series limiting electronic means.
• An electronic circuit comprising inputs for connection to an electrical distribution network, and an electrical circuit to be protected according to the invention comprises at least one overvoltage protection device as defined above comprising surge limiting means connected between said connection inputs to an electrical distribution network and said electrical circuit for protecting it against overvoltages that can be applied to the inputs.
• the electrical circuit to be protected is an electronic power supply circuit comprising a rectifier, a filter capacitor, and a converter connected downstream of the electronic serial limiting means and in parallel with the electronic means of parallel limitation. protection device.
• FIG. 1 represents a diagram of a protection device of the state of the art in an electronic circuit
• FIG. 2 represents a diagram of a protection device according to one embodiment of the invention protecting an electronic circuit
• FIG. 3 represents an operating curve of a protection device according to a first embodiment of the invention
• FIG. 4 represents an electronic circuit with a protection device according to a second embodiment of the invention
• FIG. 5 represents a variant of an electronic circuit according to one embodiment of FIG. 4;
• FIGS. 6 and 7 show circuits with three-phase protection devices according to embodiments of the invention.
• FIGS. 8, 9, 10, 11 and 12 represent variants of devices according to embodiments of the invention.
• FIGS 13 and 14 illustrate operating curves of devices according to embodiments of the invention.
• FIG. 2 shows a protection device 20 against overvoltages. It comprises an input 21 intended to be connected to a power supply network, an output 22 intended to be connected to an electrical circuit 23 to be protected, a current limiter supporting an overvoltage 25 connected between the input 21 and the output to protect said electrical circuit against overvoltages that can be applied to the input.
• the current limiter 25 comprises a bidirectional electronic circuit 26 in current and in series limiting voltage comprising at least two inputs / outputs 27, connected in series with the input 21, and leading to a low voltage drop when a current of circulation. is less than a current limiting value IHm, and limiting said current of circulation by increasing a voltage drop between said inputs / outputs.
• the bidirectional electronic series limiting circuit 26 comprises two series-connected field effect transistors 30 and 31 having their reference electrodes or sources connected to a central portion 33, their output electrodes or drains connected between said inputs / outputs 27, and their control electrodes or gates connected to said central portion, said current limiting value Ilim being defined by a control voltage threshold between the control electrodes and the respective reference electrodes and internal resistances of the transistors.
• the electronic circuit 26 comprises, in the central part 33, limiting adjustment resistors 34 connected in series with said reference electrodes, said current limiting value Ilim being also defined with values of said adjustment resistors 34.
• diodes 35 for protecting the junctions of said field effect limiting transistors 30 and 31 are connected in parallel with said current limiting resistor 34.
• the resistance values are very low of the order of a few ohms.
• the reference voltage of a transistor is of the order of 0.5 volts corresponding to a junction forward voltage which is small compared to a mains voltage.
• the electronic circuit 26 comprises, in the central part 33, first avalanche-type diodes 36 connected between the reference electrodes and the output electrodes of each transistor 30 and 31 so as to allow the direct circulation of the flow in one direction and limit a series limiting voltage VHm on the transistor to an avalanche voltage in an opposite direction.
• Said avalanche voltage of said first avalanche type diodes is preferably less than a breakdown voltage of said transistors 30 and 31, and said series limiting voltage Vlim is defined by avalanche voltages of said first avalanche diodes.
• the electronic circuit 23 comprises a rectifier, a filtering capacitor 38 connected downstream of the rectifier and a converter 15.
• an electric circuit 23 to be protected may be an electronic supply circuit comprising a rectifier 13, a filtering capacitor 38, and a converter 15 connected downstream of the series-limiting electronic means and in parallel with the electronic means of parallel limitation of the protection device.
• Figure 3 shows an operating curve of a bidirectional electronic limiting circuit 26.
• Current limiting values Ilim are positive and negative as are voltage limiting Vlim values.
• a normal operating voltage VN is very low as long as the current is below a limiting value.
• the voltage drop VN during normal operation is very low.
• the circuit 26 operates rapidly in current limiting and the voltage between its inputs / outputs increases to oppose the passage of the disturbance current.
• the circuit 26 functions as a dynamic stopper preventing the disturbance from crossing. It absorbs itself little disturbance electrical energy.
• the circuit 26 does not require a resistor or other parallel polarization component.
• FIG. 4 shows an electronic circuit with a protection device 20 with a limiter 25 comprising bi-directional electronic limiting circuits 26 series arranged in series on each supply line.
• the device of protection also comprises a parallel limiting electronic circuit 40 connected downstream of the two bidirectional electronic circuits 26 of series limitation.
• the circuit 40 limits a protection output voltage by allowing a disturbance current flow limited by the series limiting electronic circuits.
• the circuit 40 makes it possible to create a flow of current even if the downstream electronic circuit consumes little or is absent.
• the circuit 40 is connected downstream of the rectifier 13.
• said parallel limiting means 40, 41 protect said electronic circuit by directly deriving an excess perturbation current.
• a bidirectional electronic limiting circuit 26 is placed in series on the phase line and the neutral line of the supply network.
• the circuits 26 are then two in number to support the simple overvoltage of the supply voltage. Differences in the static characteristics of the transistors of the two bidirectional electronic series limiting circuits 26 make the current thresholds Ilim for each circuit 26 different or different.
• the voltage rise of the single network voltage can be done gradually over all or in cascade on each limiter. This means that the current in the mesh undergoing network overvoltage is also always limited by one of the two circuits 26.
• the first limiter circuit which initially had to support all the network overvoltage, goes into avalanche, the other circuit limiter takes over by supporting in turn the network overvoltage residual under reduced current.
• Figures 6 and 7 show circuits powered by three-phase.
• the limiter 25 comprises three series limiting electronic circuits 26.
• the parallel limiting circuit 40 is connected at the output of the limiter 25 and comprises three second diodes
• a filter 42 against high-frequency disturbances in duct mode is disposed downstream of the limiter
• the limiter 25 protects the voltage components of the filter in particular capacitors connected in parallel on the lines.
• a bidirectional electronic series limiting circuit 26 is arranged in series on each supply line. The circuits 26 are then two in number to support the overvoltage composed of three-phase supply lines. According to the static behavior of the limiters, in case of overvoltage, the rise in voltage of the network voltage is progressively done on the whole or in cascade on each limiter. This means that the current in the mesh undergoing network overvoltage is also always limited by one of the two circuits 26.
• FIG. 8 shows diagrams of different device limiters according to embodiments of the invention.
• said current limiting value Ilim is defined by a control voltage threshold between the control electrodes and the respective reference electrodes and the internal resistances of the transistors
• a series limiting voltage Vlim is defined. by an avalanche voltage between the output electrodes and the respective reference electrodes of said series limiting transistors.
• said current limiting value Ilim is defined as in FIG. 8, and a series limiting voltage Vlim is defined by avalanche voltages of first avalanche diodes 36. These diodes also protect the series limiting transistors a voltage breakdown between their output electrodes and their reference electrodes.
• said current limiting value Ilim is defined by a control voltage threshold between the control electrodes and the respective reference electrodes, the internal resistances of the transistors and the limiting resistor resistors connected to one another. series with said reference electrodes, and a series limiting voltage Vlim is defined as in the circuit of FIG. 8.
• said current limiting value Ilim is defined by a control voltage threshold between the control electrodes and the respective reference electrodes, the internal resistances of the transistors and the connected limiting resistor resistors 34. series with said reference electrodes, and a voltage of series limitation VHm is defined by avalanche voltages of first avalanche diodes 36.
• two bidirectional series limiting electronic circuits 26 are arranged in series on each supply line. The circuits 26 are then four in number for the two power lines. If the current thresholds Ilim for each circuit 26 are different, in case of overvoltage, the rise in voltage is progressively on the whole or in cascade on each limiter according to the characteristics of the transistors.
• Figures 13 and 14 show the voltage limitation performed by devices according to embodiments of the invention when applying a disturbing pulse.
• a mains voltage V1 and a voltage V2 protected downstream of a limiter 25 are at about the same value since the voltage drop is very low. Then, when a disturbance overvoltage VlP is present, the output voltage V2 is limited and the voltage difference is limited and contained by the circuits 26 of a limiter 25.
• the bidirectional electronic limiting circuits 26 series limit to a limiting voltage greater than 1000 volts.
• this limiting voltage is greater than 2500 volts or preferably greater than 3300 volts.
• the series connection of the transistors of the circuits 26 makes it possible to increase the limiting voltage.
• the transistors used in the circuits 26 withstand voltages equal to or greater than the limiting voltages Vlim respectively greater than 1000, 2500 or 3300 volts.
• the electronic means 26 of series limitation comprise field effect transistors having an on-state series resistance of less than 10 ohms.
• these field effect transistors are of the silicon carbide type allowing reduced component sizes for high operating voltages and low on-resistance.
• the electronic parallel limiting means comprise at least one avalanche diode 41 connected at the output of the electronic limiting means series. These avalanche diodes make it possible to derive a disturbance current directly upstream of the circuit to be protected.
• the transistors 30 or 31 are preferably junction field effect transistors on the gate for a negative conduction control voltage and a reverse on state.
• other types of transistors or power semiconductors can be used by adapting the schemes to their functional characteristics.

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• 2005
  • 2005-06-03 FR FR0505616A patent/FR2886778B1/fr active Active
• 2006
  • 2006-05-30 WO PCT/FR2006/001219 patent/WO2006129005A2/fr not_active Application Discontinuation
  • 2006-05-30 US US11/921,137 patent/US7791855B2/en not_active Expired - Fee Related
  • 2006-05-30 CN CN2006800197333A patent/CN101189778B/zh not_active Expired - Fee Related
  • 2006-05-30 EP EP06764696A patent/EP1886393A2/de not_active Withdrawn

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