Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/32—Means for protecting converters other than automatic disconnection
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
  • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
  • H02H7/1209—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for converters using only discharge tubes
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
  • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
  • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
  • H02H7/1225—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to internal faults, e.g. shoot-through
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
  • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
  • H02H7/125—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers
  • H02H7/1255—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers responsive to internal faults, e.g. by monitoring ripple in output voltage
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
  • H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
  • H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
  • H03K2017/0806—Modifications for protecting switching circuit against overcurrent or overvoltage against excessive temperature
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
  • H03K2217/0027—Measuring means of, e.g. currents through or voltages across the switch

Definitions

• the present invention is in the field of power bridges comprising at least one switching arm and intended to control or be powered by a rotating electric machine.
• the invention relates to a device for protecting a power component of a power bridge, as well as a power bridge and such a rotating electric machine.
• an on-board network is used to supply various electrical equipment equipping said motor vehicle.
• An electrical supply to the on-board network is provided by at least one battery which can be recharged, when the motor vehicle is in motion, by a rotary electric machine which is connected to a heat engine of said motor vehicle. The rotating electrical machine then converts mechanical energy from rotation of the heat engine into electrical energy which is supplied to the network and / or at least one battery.
• rotary electrical machine is meant more generally any rotary electrical machine, preferably whose stator is polyphase, used for the production of a direct current supplying the on-board network.
• it may in particular be an alternator or an alto-starter.
• the context of the present invention is that of rotary electrical machines with permanent magnets.
• the rotary electrical machine is connected to a power bridge comprising power components in order to supply the on-board network with direct electric current.
• the rotary electrical machine is supplied electrically by the power bridge operating as an inverter.
• the electric currents flowing in said power bridge can quickly damage its power components.
• the power components of a given arm of the power bridge In order to prevent the power components of a given arm of the power bridge from breaking and, consequently, to propagate on the on-board network electric current values incompatible with the electrical equipment of the motor vehicle, it is necessary to detect faults in the power bridge or one of its power components as quickly as possible.
• the object of the present invention is to propose a new device for protecting a power component in order to respond at least in large part to the preceding problems and also to lead to other advantages.
• At least one of the abovementioned objectives is achieved with a device for protecting a power component comprising a current input terminal, a current output terminal and a control terminal , the protection device being placed in bypass, ie in parallel between the current input terminal and the current output terminal of the power component and the protection device is configured to detect a period during which a variable electric current flows the power component between the current input terminal and the current output terminal.
• the protection device is configured to detect a period during which a variable electric current flows through said power component between its current input terminal and its current output terminal in particular when the power component is in the process of switching between a so-called blocking switching state and a so-called switching state.
• the power component In its on switching state, the power component is analogous to a switch configured in a closed state; and in its blocking switching state, the power component is analogous to a switch configured in an open state.
• the protection device is configured to detect a period during which a variable electric current flows through said power component between its current input terminal and its current output terminal for example during the transient regime of switching between the blocking conduction mode and the passing conduction mode.
• the protective device according to the first aspect of the invention may advantageously comprise at least one of the improvements below, the technical characteristics forming these improvements can be taken alone or in combination:
• variable electric current is the current passing through the power component when the power component switches from its blocking state to its on state.
• the protection device is configured to determine a potential difference across the parasitic inductors of the associated power component. .
• the potential difference generated by the parasitic inductances being proportional to an instantaneous variation of an electric current passing through said parasitic inductances
• this advantageous configuration makes it possible to directly detect said variation in electric current.
• a measurement of the potential difference thus measured makes it possible to be sensitive to the time during which the variable electric current passes through the power component between its current input and current output terminals.
• the protection device is placed in derivation of the parasitic inductances of the associated power component in order to detect the variable electric current which flows through them and - ultimately - to detect the duration during which said variable electric current flows through the component power. This measurement is used as a malfunction detector of the power component by the protection device;
• the protection device comprises a first circuit configured to generate a detection voltage proportional to the duration during which the variable electric current passes through the power component, more particularly between its current input terminal and its current output terminal;
• the first circuit comprises a detection resistor connected in series at a first midpoint with a detection capacity, said detection resistance and detection capacity being placed in parallel between the current input terminal and the current output terminal of the power component.
• the detection voltage is thus generated at the first midpoint.
• the detection resistance and the detection capacity make it possible to detect the abnormal operating states of the power component with which the protection device is associated. More particularly, the establishment of a potential difference across the parasitic inductances of the power component - induced by the variation of the electric current flowing through said power component - makes it possible to charge the detection capacity up to a value which depends on the duration of establishment of said potential difference.
• the detection capacity is weakly charged, so that it does not have sufficient voltage across its terminals to be representative of a malfunction of the component of power, as will be described later.
• the detection capacity is more charged, so that 'It represents at its terminals a sufficient voltage to be representative of the malfunction of said power component.
• the voltage across the detection capacitance corresponds to the detection voltage generated by the first circuit.
• the detection resistance and the detection capacity of the first circuit are placed in parallel with the parasitic inductors and the corresponding power component in order to measure a voltage generated by an assembly formed by the power component and its parasitic inductor (s).
• the detection resistance and the detection capacity of the first circuit are placed in derivation of the current input and current output terminals of the corresponding power component;
• the protection device comprises a thresholding device making it possible to determine a voltage threshold for controlling the power component, that is to say for switching the corresponding power component in order to put it safe and prevent it from being damaged.
• the voltage threshold corresponds to a voltage value above which the voltage across the detection capacity of the first circuit and charged by the variable electric current passing through the power component and its parasitic inductances, is - ie the detection voltage as described above, is high enough to be representative of the malfunction of the power component;
• the thresholding device comprises a first thresholding resistor connected in series at a second midpoint with a second thresholding resistor, said first and second thresholding resistor being arranged in parallel between a current input terminal and an output terminal current of the power component, the voltage at said second point making it possible to determine the voltage threshold.
• the choice of the value of the threshold resistances makes it possible to adjust and fix the voltage threshold described above;
• the voltage threshold is equal to the sum of the voltage at the second point and the voltage across the first diode
• the protection device comprises a circuit for controlling the power component between the terminals of which the protection device is arranged as a bypass, said protection circuit controlling the power component as a function of the voltage detection generated by the first circuit and the voltage threshold predetermined by the thresholding device.
• the control circuit makes it possible to switch said power component into one or other of its switching states described above, when the voltage across the detection capacity of the first circuit, c ' that is to say the detection voltage as described above, is high enough to be representative of a malfunction of said power component;
• control circuit comprises a control switch and a voltage comparator configured to compare the detection voltage generated by the first circuit and the voltage threshold predetermined by the thresholding device, said control switch being configured to switch the component corresponding power in a blocking conduction state when said voltage comparator detects that said detection voltage is greater than said predetermined voltage threshold.
• control switch further comprises a first transistor, the current input terminal of which is connected to the control terminal of the power component by means of a resistor, and the current output terminal of which is connected to the current output terminal of the power component, said first transistor being in a conducting state when said detection voltage is higher than said predetermined voltage threshold.
• the first transistor is a MOSFET type transistor.
• the first transistor is an N-doped MOSFET type transistor
• the voltage comparator also includes:
• a second transistor whose control terminal is connected to the second midpoint, whose current input terminal is connected to the first midpoint via a first diode and whose current output terminal is connected to the control terminal of the first transistor, and o a bias resistor connected by one of its terminals to the control terminal of the first transistor and by the other of its terminals to the current output terminal of the power component.
• the second transistor is a bipolar transistor
• the second transistor is a bipolar transistor of the P doped type
• the threshold value from which the protection device according to the first aspect of the invention determines that the associated power component malfunctions also depends on the power components and / or the applications considered.
• the dimensioning of the different electronic components forming the protection device according to the first aspect of the invention also depends on the power components and / or the applications considered.
• the protection device according to the first aspect of the invention or according to any of its improvements generates a detection voltage proportional to this duration of abnormally long establishment of the variable electric current passing through the power component.
• the detection voltage corresponds more particularly to the electrical charging of the detection capacity of the first circuit, and more particularly to the potential difference across the terminals of said detection capacity.
• a switching arm of a power bridge electrically connected to a rotating electrical machine by an electrical network said switching arm of the power bridge comprising:
• first and a second power component operating as controlled switches and arranged in series with respect to each other and between the ground terminal and the supply terminal, an intermediate point located between the first power component and the second power component being intended to be electrically connected to an electric phase of the rotary electric machine;
• switching arm comprises at least one protection device according to any one of the preceding claims, said at least protection device being arranged in derivation of the current input and current output terminals of one of the components of power of said switching arm.
• the switching arm according to the second aspect of the invention may advantageously comprise at least one of the improvements below, the technical characteristics forming these improvements can be taken alone or in combination:
• the first and second power components are of the MOSFET type (English acronym for “Metal Oxide Semiconductor Field Effect Transistor” and which translates as a field effect transistor with a metal-oxide-semiconductor structure).
• the first and second power components are of the IGBT type (English acronym for “Insulated Gâte Bipolar Transistor” and which translates as bipolar transistor with insulated gate.
• the first and the second power component can be of any type other type compatible with the present invention;
• the MOSFET forming the first and / or the second power component is of the N doped type
• a power bridge comprising comprising at least one switching arm in accordance with the second aspect of the invention or according to any one of its improvements.
• a rotary electrical machine comprising a rotor and a stator having several electrical phases, the rotary electrical machine being electrically connected to a power bridge according to the third aspect of the invention.
• the rotary electrical machine can be of the synchronous or asynchronous type.
• the rotary electrical machine is of the type of a permanent magnet machine.
• FIGURE 1 illustrates a schematic view of an electrical network comprising a rotating electrical machine electrically connected to a power bridge according to the invention
• FIGURE 2 illustrates a schematic view of the principle of detecting failures of a switching arm of a power bridge
• - FIGURE 3 illustrates a block diagram of a first embodiment of a protection device associated with a power component of the first stage of a switching arm of the power bridge;
• the characteristics, the variants and the various embodiments of the invention can be associated with one another, according to various combinations, insofar as they are not incompatible or mutually exclusive of each other.
• variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from in the prior art.
• a rotary electrical machine 2 is electrically connected to a power bridge 1 configured to supply an on-board network B + with direct current from the rotary electrical machine 2 or to supply the rotary electrical machine 2 from of the on-board network B +.
• the rotary electric machine is for example of the GMG type (in English “Gear Motor Generator”) developing an electric power of 15 kW. All the numerical values mentioned below relate to this example of a particular electrical machine which in no way limits the scope of the invention.
• the on-board network B + is electrically connected to at least one battery 4.
• the stator 21 of the rotary electric machine 2 is polyphase: the stator 21 comprises a plurality of electric windings 211 inside which electric currents circulate, each electric current flowing in one of the electric phases F1- F3.
• the stator 21 of the rotary electrical machine 2 comprises three electrical phases F1-F3, but the invention is more generally understood for an electrical machine whose stator comprises at least one phase electric.
• the rotary electric machine 2 is advantageously a synchronous electric machine with permanent magnets 221, as shown in FIGURE 1.
• the rotary electrical machine 2 is preferably of the type of an alternator or a starter-alternator.
• a rotor 22 of the rotary electrical machine 2 is advantageously mechanically coupled to a heat engine of the motor vehicle.
• the rotor 22 advantageously comprises the permanent magnets 221 in the context of a synchronous machine.
• the rotating electrical machine 2 is electrically interfaced by the power bridge 1 to the on-board network B +.
• the power bridge 1 comprises at least one switching arm 10, and preferably a plurality of switching arms 10.
• Each switching arm 10 comprises a first El and a second E2 stage, each stage comprising a switch comprising an input terminal current, a current output terminal and a switch control terminal for switching the switch from a closed state to an open state, and vice versa.
• the power bridge 1 is controlled by a control module - not shown - which selectively or collectively configures the control terminals of the switches to place said switches in their open or closed state.
• the control module thus makes it possible to control the power bridge.
• the switches are preferably made by means of power components Ql, Ql 1.
• each of the power components (Ql, Qll) comprises:
• the first power component Ql and the second power component Ql 1 are arranged in series with respect to each other, between the ground terminal GND and the terminal d increase in the on-board network B +, each midpoint 11a-11c being located between the first power component Ql and the second power component Ql 1.
• the first Ql and the second Qll power component of each switching arm 10 are interconnected at the middle bridge 11a-llc located between their respective current output and current input terminals.
• a current input terminal D of the first power component Q1 is intended to be connected to the on-board network B +; and a terminal of current output of the second power component Qll is intended to be connected to the ground of the electrical network.
• the power bridge 1 is electrically connected to each of the electrical phases F1, F2, F3 of the rotary electrical machine 2 in order to supply DC voltage to the on-board network B + and / or to charge the at least one battery 4.
• each switching arm 10 of the power bridge 1 is electrically connected to one of the electrical phases F1, F2, F3 of the rotary electric machine 2. More particularly still, each switching arm 10 of the power bridge is connected electrically to one of the electrical phases F1, F2, F3 of the rotary electrical machine 2 at its midpoint lla-llc located between the first stage El and the second stage E2 of each switching arm 10.
• each first power component Ql is electrically connected to a protection device 100 configured to measure a period during which a variable electric current passes through said first power component Ql between its current input terminal D and its output terminal current S, and possibly to control it as a function of said measurement carried out. More particularly, each protection device 100 is placed as a bypass of the current input terminal D and of the current output terminal S of the first corresponding power component Ql.
• each second power component Q11 is electrically connected to a protection device 100 configured to measure a period during which a variable electric current passes through said second power component Q1 between its current input terminal D and its terminal current output S, and possibly to control it as a function of said measurement carried out.
• the protective device (s) in accordance with the first aspect of the invention or according to any of its improvements takes control of the control module when a malfunction is detected on the at least one of said power components Ql, Ql 1.
• each protection device 100 is configured to detect a potential difference across the parasitic inductors Ll_D, Ll_S, L2_D, L2_S visible in FIGURE 2 and located at the drain and the source within the component power Ql, Qll associated.
• each first Ql and second Ql 1 power component are of the N-doped MOSFET type.
• the drain, the source and the gate of the N-doped MOSFET transistors correspond respectively to the terminal. current input, output terminal current and the switch control terminal.
• the invention is not limited to this single type of power component, and each first Q1 and second Qll power component can be of the type of any transistor.
• FIGURE 2 illustrates a switching arm 10 of the power bridge, in which the first MOSFET Q1 of the first stage El is associated with a protection device 100 in accordance with the first aspect of the invention or according to any of its improvements, said protection device 100 being placed in bypass between the drain terminal D and the source terminal S of the MOSFET Q1.
• the first MOSFET Q1 and the second MOSFET Q11 of each switching arm 10 are interconnected at the intermediate point lla-llc located between the source terminal S of the first MOSFET Q1 and the drain terminal D of the second MOSFET Q2.
• the drain terminal D of the MOSFET Ql is intended to be connected to the on-board network B +; and the source terminal S of the MOSFET Q11 is intended to be connected to a ground terminal GND of the electrical network.
• each MOSFET Q1, Q11 has a parasitic drain inductance L1_D, L2_D at the level of the drain terminal D of said corresponding MOSFET Q1, Q1 1; and each MOSFET Q1, Qll has a parasitic inductance of source L1_S, L2_S at the level of the source terminal S of said corresponding MOSFET Q1, Qll.
• the switching arm 10 also includes parasitic inductances L3 representing the inductive effects of the electrical conductors of the power bridge 1.
• the invention in accordance with its first aspect aims to determine a period during which a variable electric current flows between the drain terminal D and the source terminal S of the MOSFET Ql, Qll associated when the latter is in its transient tilting regime from the blocking conduction state to the passing conduction state.
• a coupled conduction duration At cc is defined as being the maximum admissible duration of the transient tilting regime of the MOSFET Q1, Qll operating normally.
• the coupled conduction time At cc can be defined as: Where icc is the maximum coupled conduction current flowing in the first MOSFET Ql and in the second MOSFET Ql 1, thus representing the maximum admissible current in the switching arm 10 to dissociate normal operation of said MOSFET Ql, Qll from a malfunction of said MOSFET Ql, Ql 1.
• the invention thus aims to have each protection device 100 in bypass (ie in parallel) from the drain D and source S terminals of one of the MOSFETs Ql, Qll of the power bridge 1 in order to measure the duration during which the variable electric current flows through said MOSFET Ql, Ql 1 corresponding between said drain terminal D and said source terminal S.
• FIGURE 3 illustrates an exemplary embodiment of a protection device 100 in accordance with the first aspect of the invention and implemented to detect the duration of establishment of such a variable electric current between the drain D and source S d terminals.
• the characteristics described below apply mutatis mutandis to a protection device 100 associated with a MOSFET Q11 of a second stage E2 of the bridge of power 1.
• the protection device 100 is connected in bypass, i.e. in parallel, between a drain terminal D and the source terminal S of the MOSFET Ql. In addition, the protection device 100 is also electrically connected to a gate terminal G of the MOSFET Ql
• the protection device 100 comprises a first circuit 110 configured to generate a detection voltage proportional to the duration during which the variable electric current crosses the MOSFET Ql between its drain terminal D and its source terminal S.
• the first circuit 110 is placed in bypass with respect to the drain D and source S terminals of the MOSFET Ql.
• the first circuit 110 comprises a detection resistance R8 connected in series with a detection capacity Cl.
• the detection resistance R8 and the detection capacity Cl are placed in parallel between the drain terminal D and the source terminal S of the MOSFET Ql.
• the detection resistor R8 and the detection capacitor C1 together form a circuit which makes it possible to detect a malfunction of the MOSFET Ql. More particularly, the establishment of a potential difference across the parasitic inductances of the MOSFET Ql - induced by the variation of the electric current flowing through said MOSFET Ql when the latter is in its transient tilting regime from the blocking conduction mode to the on conduction mode - allows the detection capacity C1 to be loaded up to a value which depends on the duration during which said potential difference exists.
• the MOSFET Ql is crossed by a variable electric current during a transition time less than or equal to 400ns, then the electric current reaches a value of about 400A and the detection capacitor C1 has at its terminals a first voltage representative of a transient normal tilting regime of the MOSFET Q1.
• the MOSFET Ql is crossed by a variable electric current for a transition duration at least equal to about 1 ps, then the electric current exceeds the threshold of 1000 or 2000A and the detection capacity Cl is charged at a second voltage (greater than the first voltage) representative of an abnormal transient state of said MOSFET Q1.
• the detection capacitor Cl is discharged through a first discharge diode D2 placed in derivation of the detection resistance R8 or through a second discharge diode D7 and d a discharge resistor R4 placed in series with said discharge diode D7, said series assembly of the second diode D7 and of the discharge resistor R4 being connected in parallel with the detection capacitor C1.
• Values of the detection resistance R8 and of the detection capacity Cl are notably determined as a function of the coupled conduction time At cc as described with reference to FIGURE 2.
• the first measurement point VCl_l - VCl_3 located between the detection resistance R8 and the detection capacity Cl is particularly interesting in the context of the invention because it corresponds to the detection voltage generated by the first circuit 110 and corresponding to the duration establishment of the variable electric current between the drain D and source S terminals of the MOSFET Ql in its transient tilting regime.
• the detection voltage taken at the terminals of the detection capacity C1 can be used as a detection signal used for example by a supervision system of the power bridge 1 or to warn a user of a malfunction of the power bridge.
• the protection device 100 also includes a thresholding device 120 and a control circuit 130.
• the thresholding device 120 is configured to determine a voltage threshold from which said protection device 100 can optionally control the MOSFET Q1 to make it secure, for example.
• the voltage threshold corresponds to the threshold value beyond which the detection voltage across the detection capacity Cl of the first circuit 110 and charged by the variable electric current passing through the MOSFET Ql and its parasitic inductances during the transient state of tipping is high enough to be representative of the MOSFET Ql malfunction.
• the thresholding device 120 comprises a first threshold resistor R2 connected in series with a second threshold resistor R3.
• the first and second threshold resistors R2, R3 are arranged in parallel between the drain terminal D and the source terminal S of the MOSFET Ql.
• Values of the first and second threshold resistances R2, R3 are determined in particular as a function of the coupled conduction time At cc as described with reference to FIGURE 2.
• the values of the first and second threshold resistors R2, R3 make it possible to fix a value of the accessible voltage threshold on a threshold terminal 121 located between the two threshold resistors R2, R3.
• This threshold value makes it possible in particular to set the value from which the charge accumulated in the detection capacity Cl is representative of a malfunction of the MOSFET Ql during its transient switching regime. Below this threshold value, the detection voltage generated by the first circuit 110 is representative of normal operation of the MOSFET Ql during its transient tilting regime.
• the protection device 100 can also use this detection voltage to control the MOSFET Q1 as a function of the value of said detection voltage.
• control circuit 130 includes a control switch, here an N-doped MOSFET transistor Q3 and a voltage comparator configured to compare the voltage of detection generated by the first circuit 110 and the voltage threshold predetermined by the thresholding device 120.
• the control circuit 130 is configured to control the MOSFET Q1 as a function of the detection voltage generated by the first circuit 110 and the voltage threshold predetermined by the thresholding device 120.
• control circuit 130 makes it possible to switch the MOSFET Q1 into its blocking state, when the detection voltage across the detection capacitance C1 of the first circuit 110 is high enough to be representative of a malfunction. of said first MOSFET Q1, due to the presence of a variable electric current for an abnormally long period during the transient switching regime of said MOSFET Q1.
• the voltage comparator consists of a transistor Q2.
• the transistor Q2 of the comparator is of the type of a bipolar transistor of which an emitting terminal E is electrically connected between the detection resistance R8 and the detection capacity Cl of the first circuit 110 by the diode D4, and a base terminal B of which is electrically connected between the threshold resistors R2, R3 of the thresholding device 120.
• the transistor Q2 of the comparator of the control circuit 130 is preferably of the type of a PNP type bipolar transistor.
• This voltage comparator is configured to compare the detection voltage generated by the first circuit 110 and the voltage threshold predetermined by the thresholding device 120. More particularly, the thresholding device 120 imposes on the base terminal of the transistor Q2 a voltage equal to the voltage threshold while the first circuit imposes on the emitting terminal E a voltage equal, apart from the voltage drop across the diode D4, to the detection voltage generated by the first circuit 110. If the voltage detection at the terminals of the detection capacity Cl of the first circuit 110 is greater than the voltage threshold, then the transistor Q2 turns on, which means that the first control circuit 130 secures the MOSFET Ql, by reconfiguring it in its state blocking switch.
• control circuit 130 also includes a control switch, here in the example described an N-doped MOSFET transistor Q3, in order to control the switching of the MOSFET Q1 as a function of the comparison carried out by the circuit voltage comparator. 130.
• the transistor Q3 of the control circuit 130 is configured to lower the source gate voltage of the MOSFET Ql when the result of the comparison between the detection voltage and the threshold value is representative of a malfunction of the MOSFET Ql. in its transient changeover regime.
• a gate terminal G of the control switch Q3 is electrically connected to a collector terminal C of the transistor Q2, the gate terminal G of the control switch Q3 being moreover connected to the source terminal S of said control switch Q3 via a polarization resistance R7.
• the source terminal S of the control switch is electrically connected to the source terminal S of the MOSFET Q1; and a drain terminal D of the control switch Q3 is electrically connected to the gate terminal G MOSFET Ql by means of a diode Dl and a damping resistor R6 making it possible to damp electrical oscillations when the control switch Q3 is in its conducting state.
• the diode Dl also makes it possible to avoid a feedback from the source of the MOSFET Ql on the gate of the MOSFET Ql during a switching of the MOSFET Ql.
• the control switch Q3 of the first control circuit 130 makes it possible to interpret the result of the comparison between the detection voltage taken at the terminals of the detection capacity C1 of the first circuit 110 and the threshold value determined by the thresholding device 120. If the detection voltage across the detection capacitor C1 is greater than the threshold value, then the transistor Q2 of the first control circuit 130 is configured in its conducting state. Subsequently, the control switch Q3 is in turn configured in its conduction state passing which brings the voltage to the gate terminal G of the MOSFET Ql to the source voltage of this MOSFET Ql in order to put it in safety, by configuring in its blocking switching state.
• the first protection device 100 comprises a resistor R5 placed in series with the gate terminal G of the MOSFET Q1.
• a bias resistor R9 is also located between the gate terminal G and the source terminal S of the MOSFET Ql.
• the detection capacity C1 of the first circuit 110 is discharged before the MOSFET Q1 switches from its blocking conduction state to its passing conduction state.
• the detection capacity Cl of the first circuit 110, placed in derivation of said drain terminal D and said source terminal S is responsible for the presence of this variable electric current.
• the duration of the abnormally long transient regime makes it possible to charge the detection capacity C1 of the first circuit to a level higher than the threshold value defined by the first thresholding device 120 and making it possible to identify the malfunction of the MOSFET Q1.
• the detection capacity C1 makes it possible to configure the transistor Q2 of the comparator of the control circuit 130 in its conducting state.
• the control switch Q3 of the first control circuit 130 is in turn polarized in its conducting state in order to short-circuit the gate terminal G and the source terminal S of the MOSFET Q1 in order to configure it in its blocking state and thus to dissociate the two stages El, E2 of the switching arm 10 of the power bridge 1 by opening the first stage El.
• the period during which a variable electric current flows through a power component and beyond which there is a risk of damage to the power component depends of course on the power components and / or the applications considered. Therefore, the threshold value from which the protection device according to the first aspect of the invention determines that the associated power component malfunctions also depends on the power components and / or the applications considered.
• the dimensioning of the various electronic components forming the protection device according to the first aspect of the invention and in particular the values of the detection resistance R8, of the detection capacity Cl of the first discharge diode D2 of the first R2 and second R3 threshold resistors as well as the diode D4 depend on the power components and / or the applications considered and / or on the electrical power of the rotary electrical machine 2 with which the power bridge 1 is associated.
• the values cited in the description presented above are given only by way of nonlimiting examples and those skilled in the art could of course assign other values to them, collectively or selectively, in order to adapt the exemplary embodiments. described in other situations, for example to adapt the detection time from which the power component Q1, Qll is considered to no longer function normally during its transient tilting regime.
• the invention relates in particular to a protection device 100 of a power component Ql, Ql 1 configured to detect an abnormally long establishment time of a variable electric current between the terminals of said power component Ql, Qll during its transient changeover regime.
• the protection device 100 advantageously takes advantage of the parasitic inductances of the power component Ql, Qll in order to charge a detection capacity Cl, Cil at a level which depends on the duration during which said power component Ql, Qll is crossed by the current variable electric. This detection is then used to possibly control the power component Ql, Qll in order to put it in safety.
• the invention also relates to a power bridge 1 comprising at least one such protection device 100 for examining the transistors which compose it, and a rotating electric machine 2 controlled by such a power bridge 1.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Emergency Protection Circuit Devices (AREA)
• Amplifiers (AREA)
• Inverter Devices (AREA)

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• 2018
  • 2018-06-29 FR FR1856057A patent/FR3083394B1/fr active Active
• 2019
  • 2019-06-28 CN CN201980043868.0A patent/CN112352373A/zh active Pending
  • 2019-06-28 EP EP19733085.5A patent/EP3815227A1/de active Pending
  • 2019-06-28 WO PCT/EP2019/067469 patent/WO2020002675A1/fr active Application Filing

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