Contactor, integrated circuit, method for interrupting the flow of current

Abstract

To provide a contactor for selectively connecting and disconnecting a battery of an electric or hybrid vehicle to / from an electric load, and an integrated circuit, and a method of interrupting a current flow.SOLUTION: Respective primary switches of two contactors each have a movable part that is driven by an actuator. A magnetic sensor for measuring a primary current flowing through an electrical conductor portion and a controller connected to the magnetic sensor and to the actuator are provided. The controller is configured to receive a command to open a switch 407, operate the actuator 408, detect if the primary switch is actually open 410, and blow a fuse if the switch is not open 400.SELECTED DRAWING: Figure 4A

Description

[Technical Field]

[0001] The present invention relates generally to the field of power circuits, and more particularly to a contactor, integrated circuit, and method for interrupting current flow for selectively connecting and disconnecting a battery in an electric or hybrid vehicle to / from an electric load. [Background technology]

[0002] The motor of an electric vehicle (EV) or hybrid vehicle (HV) may be powered by a battery providing a voltage ranging from about 200 volts to about 800 V, or even greater. The battery may be capable of providing a current having a magnitude of up to about 1500 amperes, with current peaks of up to 3000 amperes or even greater. Needless to say, the power circuits of such vehicles pose a potential threat to passengers. For safety reasons, faults in the power circuits and / or the battery itself should be detected and repaired quickly; for example, some faults must be detected within 5 ms.

[0003] In such vehicles, contactors are typically used to selectively connect and disconnect the battery to / from the electric motor or to / from the charging circuit under normal circumstances. The power circuit may further include a fuse to open the circuit in case of an emergency, for example in the event of a collision.

[0004] Patent document 1 (US2014 / 292109(A1)) describes a contactor device including a current sensor for use in an electric vehicle (EV) or hybrid vehicle (HV).

[0005] There is always room for improvement or substitution. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2014 / 292109 Summary of the Invention

[0007] It is an object of an embodiment of the present invention to provide a contactor for use in an electric or hybrid vehicle, particularly an electric and / or hybrid vehicle.

[0008] It is an object of embodiments of the present invention to provide a power circuit including such a contactor, and an electric vehicle including such a power circuit.

[0009] It is an object of an embodiment of the present invention to provide a method for interrupting the current flowing through such a contactor.

[0010] It is an object of embodiments of the present invention to provide an integrated circuit for carrying out such a method.

[0011] It is an object of an embodiment of the present invention to provide a contactor that has a switch and is further capable of measuring and interrupting the current.

[0012] It is an object of embodiments of the present invention to provide a contactor that has improved reliability (in terms of being able to stop the flow of current) and / or has improved lifespan, preferably both.

[0013] It is an object of embodiments of the present invention to provide a power circuit including such a contactor, which power circuit offers improved safety and / or has an improved lifespan, preferably both.

[0014] It is an object of embodiments of the present invention to provide an integrated circuit for performing such a method faster and / or more efficiently and / or more reliably.

[0015] These and other objects are achieved by a contactor, by a power circuit, by a method for interrupting current flowing through a contactor, and by an integrated circuit according to embodiments of the present invention.

[0016] According to a first aspect, the present invention provides a contactor comprising: a first power terminal; a second power terminal; a sub-circuit electrically connected between the first and second power terminals and including at least three elements connected in series: a conductor portion; a main switch (also referred to herein as a "high voltage switch" or "HV switch"); and a fuse, wherein the main switch includes a moving part actuated by an actuator; a magnetic sensor configured to measure a primary current (also referred to herein as a "high voltage current" or "HV current") flowing through the conductor portion; and a power supply communicatively connected to the magnetic sensor for measuring the primary current flowing through the conductor portion and for controlling the switch. and a controller operably connected to said actuator for selectively opening and closing the contactor, wherein the contactor further includes detection means for detecting whether the main switch is actually open or closed, and the controller is configured to (i) measure the primary current to detect whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continue with step ii), and if not, repeat step i); (ii) operate the actuator to open the main switch; and (iii) detect whether the main switch is effectively open, and if it is detected that the main switch is still closed (e.g., after a time interval Δt), blow a fuse.

[0017] The time interval Δt may be a predefined time interval or may be calculated (e.g., using a look-up table) as a function of the measured HV current. This period may be determined only once after measuring the HV current, or may be dynamically adjusted or updated (based on ongoing HV current measurements).

[0018] The "first power terminal" may be connected or connectable (directly or indirectly) to a battery. The "second power terminal" may be connected or connectable (directly or indirectly) to an electric motor.

[0019] The advantage is that the magnetic sensor can measure the primary current in a contactless manner, which allows it to operate at (relatively) low voltages (e.g., up to 48 volts).

[0020] A key advantage is that the contactor can detect itself using the detection means whether the switch is effectively open or closed without the need to communicate with an external device and in a manner that is not dependent on measurements from a magnetic sensor, because this shortens the feedback loop and thus provides extra time during which an attempt to open the switch using the actuator can be made without the need to blow a fuse. In other words, the advantage of this contactor is that it can first attempt to open the switch in a reversible manner (e.g., under certain conditions where the HV current is below a certain value), which may not be possible if valuable time is lost due to communication with other devices (e.g., an external processor). By shortening the communication or decision-making loop, the probability of needing to blow a fuse due to insufficient time can be reduced.

[0021] The advantage is that the "detection means" provides a way to perform internal diagnostics in a manner independent of the current measurements performed by the magnetic sensor. In other words, the advantage is that the switch can be operated in a closed loop manner (i.e., feedback in addition to forward operation). In this way, the reliability of the contactor can be increased, improving the safety of the power system in which it is used.

[0022] Detecting an overcurrent condition may involve comparing the measured HV current to a predefined value, or may involve or be based on the classical I2T (Ampere-squared-second) technique.

[0023] The "first power terminal" may be connected or connectable (directly or indirectly) to a battery. The "second power terminal" may be connected or connectable (directly or indirectly) to an electric motor or a two-phase or three-phase converter.

[0024] The advantage is that the fuse is connected in series with the main switch, because this allows the HV current to be interrupted without the main switch having to open.

[0025] The step of "detecting an overcurrent condition" may include comparing the measured current to a predefined threshold.

[0026] The step of "detecting an overcurrent condition" may include calculating an I2T value (Ampere-squared-seconds) over time and comparing this value to a predefined threshold.

[0027] In an embodiment, the controller is configured to: a) repeatedly (e.g., periodically) measure the primary current flowing through the conductive portion using the magnetic sensor; b) detect whether an overcurrent condition has occurred based on the (e.g., periodically) measured primary current, and if it is detected that an overcurrent has occurred, proceed with step c); c) determine an available period (e.g., Δtav) for opening the main switch, for example as a function of the measured current value; d) compare the available period (Δtav) with a period required to open the main switch (Δtreq); if the available period is less than the required period, proceed with step g); otherwise, proceed with step e); e) operate the actuator to open the main switch; and f) detect using the detection means whether the main switch is effectively opened within the available period (Δtav), and blow the fuse if the main switch is still closed after the available period (Δtav).

[0028] As mentioned above, the opening of the switch can be or will be triggered by (at least) receiving a corresponding command from an external processor (eg, ECU).

[0029] In an embodiment, the controller has at least one communication port connectable to an external processor, and the controller is further configured to receive at least one command selected from the group consisting of a command to close the switch, a command to open the switch, and a command to blow the fuse, and the controller is further configured to perform at least one of: (x) upon receiving the command to close the switch, operate the actuator to close the main switch; (y) upon receiving the command to open the switch, perform steps ii) and iii); and (z) upon receiving the command to blow the fuse, blow the fuse.

[0030] In some embodiments, performing steps ii) and iii) may be performed by performing step a) and steps c) through g).

[0031] In an embodiment, the contactor is capable of conducting a current of at least 60 amps (or at least 75 amps, or at least 100 amps, or at least 125 amps), and the contactor further includes third and fourth power terminals for receiving a voltage source of up to 48 volts (or up to 36V, or up to 24V, or up to 12V).

[0032] This voltage is referred to herein as the "low voltage power supply." This low voltage may be provided by a second battery that is not intended to power the vehicle's motor, but is intended to power the control circuitry. At least the controller, actuator, detection means, and magnetic sensor are powered by the low voltage power supply.

[0033] The high voltage and low voltage regions are galvanically separated. An advantage of using a magnetic sensor, preferably located in close physical proximity to, but galvanically isolated from, the conductive portion, is that the magnetic sensor allows circuitry in the low voltage region to measure current flowing to the high voltage region, i.e., through the conductive portion.

[0034] In an embodiment, the fuse is or includes a pyrofuse or squib.

[0035] In an embodiment, the actuator includes a coil and an element that is movable relative to the coil. The actuator may further include a spring biased to open the switch (NO type) or a spring biased to close the switch (NC type).

[0036] In an embodiment, the controller is further configured to measure a secondary current flowing through the coil, and the controller is further configured to determine the primary current based on the signal obtained from the magnetic sensor and taking into account the secondary current.

[0037] The signal obtained from the magnetic sensor itself may be corrected for the magnetic field generated by the coil at the location of the magnetic sensor, for example by subtracting from the primary current value the secondary current value multiplied by a predefined constant. In this way, the current flowing through the conductive part can be measured accurately while at the same time allowing a compact design (the magnetic sensor and the coil may be relatively close to each other, and magnetic shielding is not absolutely necessary).

[0038] In an embodiment, the detection means includes a shunt resistor configured to measure the current flowing through the actuation means, and the controller is further configured to measure the voltage across the shunt resistor to determine the current flowing through the shunt resistor and through the coil, and the controller is further configured to repeatedly (e.g., periodically) sample the current flowing through the shunt resistor, thereby obtaining a current waveform, and to analyze the current waveform to detect characteristics indicative of movement of the movable element.

[0039] In an embodiment, the detection means comprises a position sensor (e.g. a magnetic position sensor, e.g. based on the magnetic field emitted by a permanent magnet) for detecting the position of the movable element, and the controller is connected to said position sensor for determining the position of the movable element and thereby the status of the switch (i.e. open or closed).

[0040] In an embodiment, the magnetic sensor includes at least one horizontal Hall element, or at least one vertical Hall element, or at least one magnetoresistive element positioned in the vicinity of the conductive portion and configured to measure magnetic field components generated by a current flowing through the conductive portion.

[0041] In this embodiment, the controller may determine the current flowing through the conductive portion as being proportional to the measured magnetic field component.

[0042] A magnetic shield may be provided in the vicinity of the magnetic sensor to reduce influences from external disturbance fields or from the actuator coil.

[0043] In an embodiment, the magnetic sensor includes at least two horizontal Hall elements or at least two vertical Hall elements spaced apart and oriented parallel to one another and configured to measure a magnetic field differential or a magnetic field gradient.

[0044] In this embodiment, the controller may determine the current flowing through the conductive portion as being proportional to the magnetic field difference or magnetic field gradient. An advantage of utilizing a magnetic field gradient is that magnetic field disturbance fields can be reduced.

[0045] In an embodiment, the contactor further includes a temperature sensor mounted near the magnetic sensor (e.g., integrated on the same semiconductor substrate) for measuring the temperature of the magnetic sensor, and the controller is further configured to take the temperature of the magnetic sensor into account when converting the magnetic field value to a current value (e.g., to perform temperature compensation). In this way, the accuracy of the signal can be further improved.

[0046] In an embodiment, the contactor further includes an accelerometer and / or a gyroscope connected to a controller, the controller being further adapted to determine an abnormal condition (e.g., a collision has occurred or the vehicle is oriented upside down after falling from a bridge) based on signals obtained from the accelerometer and / or the gyroscope, and the controller being further configured to autonomously open the main switch and / or blow the fuse when the abnormal condition is detected, for example by analyzing certain parameters (e.g., acceleration parameters or orientation parameters).

[0047] In an embodiment, the controller is implemented in an integrated semiconductor device, the magnetic sensor is also integrated in the semiconductor device (e.g., in the same packaged device as a separate component on a lead frame or integrated on the same silicon substrate as the controller), the actuator includes a coil connected in series with a second switch, the detection means includes a shunt resistor connected in series with the coil, the controller is configured to sample a first voltage across the shunt resistor and to sample a second voltage across the coil or across the series connection of the coil and the shunt resistor, and to determine the status of the main switch based on the first and second voltage samples, the controller has a first output for controlling the actuator to operate the main switch, and the controller has a second output for blowing the fuse.

[0048] The controller may further include an analog-to-digital converter (ADC), a timer, a clock circuit, non-volatile memory (eg, flash), a PWM module, and the like.

[0049] According to another aspect, the present invention also provides a power circuit comprising an electric battery for providing electrical power, an electric load comprising an electric motor, and a contactor according to any one of the preceding claims connected to the battery by a first power terminal and to the electric load by a second power terminal, or vice versa.

[0050] The electrical load may further include a three-phase converter.

[0051] According to another aspect, the present invention also provides an electric or hybrid vehicle including a contactor according to the first aspect, or a power circuit according to the second aspect.

[0052] The electric vehicle may further include at least one airbag.

[0053] The electric vehicle may further include an engine control unit (ECU) connected to the contactor through the communication port, and the ECU may be configured to provide a signal to the contactor to open the switch based on a signal obtained from the airbag.

[0054] According to another aspect, the present invention also provides a method of interrupting current flowing through a contactor according to the first aspect, comprising the steps of: (i) measuring a primary current flowing through a conductive portion to detect whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continuing with step ii), and if not, repeating step i); ii) operating an actuator to open or attempt to open the main switch; and iii) detecting whether the main switch is effectively open, and blowing a fuse if it is detected after a time interval (Δtav) that the main switch is still closed.

[0055] Step i) may include the optional step of determining the available time period Δtav based on the measured current. Because step ii) takes some time, in some embodiments it is possible to continue measuring the current and dynamically update the available time period Δtav.

[0056] According to another aspect, the present invention also provides a method of interrupting current flowing through a contactor according to the first aspect, the method comprising: a) repeatedly (e.g., periodically) measuring a primary current flowing through a conductive portion of the contactor using a magnetic sensor; b) determining an available time for opening a main switch (e.g., according to a predefined safety standard), optionally as a function of the measured current; c) comparing the available time with a time typically required to open the main switch, and if the available time is less than the typically required time, proceeding with step f), otherwise proceeding with step d); d) operating an actuator to open the main switch; and e) detecting using detection means whether the main switch is effectively opened within the available time period, and blowing a fuse if the main switch is still closed after the available time period.

[0057] According to another aspect, the present invention also provides an integrated circuit for use in a contactor according to the first aspect, the integrated circuit comprising: said controller in the form of a programmable processor; said magnetic sensor (e.g. in the form of a circuit including a horizontal Hall element, or a vertical Hall element, or a magnetoresistive element); a shunt interface for sensing a voltage across a shunt resistor connectable to the integrated circuit, from which voltage the secondary current can be determined; a voltage sensing interface for sensing the voltage across the coil; a first output for driving an actuator connected to a main switch; and a second output for actuating a fuse driver (e.g. a pyro fuse driver). wherein the processor is configured to: i) measure the primary current using the magnetic sensor to detect whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continue with step ii), and if not, repeat step i); ii) assert a first output to operate an actuator to open or attempt to open the main switch; and iii) detect whether the main switch is effectively open by analyzing signals obtained from the shunt interface and signals obtained from the voltage sensing interface, and assert a second output to blow a fuse if it is detected after a period of time that the main switch is still closed.

[0058] The present invention also provides a variation of the integrated circuit (illustrated in FIG. 6 ) in which the shunt interface, the voltage interface, and the first output are omitted, but the integrated circuit includes an integrated shunt resistor and transistor operably connected to the coil interface.

[0059] The integrated circuit also preferably includes an analog-to-digital converter configured to digitize signals obtained from the shunt interface and configured to digitize signals obtained from the voltage sense interface.

[0060] The shunt interface may include one or two dedicated input pins at which such voltages are measured.

[0061] The voltage sense interface may include one or two dedicated input pins, one of which may be shared with the shunt interface.

[0062] The integrated circuit preferably further includes a non-volatile memory embedded in or connected to the processor. The non-volatile memory may include data corresponding to the current versus time curve. The non-volatile memory also preferably includes a computer program or code fragments including executable instructions for performing one of the above-described methods, or some or all of the above-described method steps, when executed by the programmable processor.

[0063] In an embodiment, the integrated circuit further includes a digital communication interface for receiving instructions from an external processor (e.g., from an external ECU), and is further configured to perform steps ii) and iii) upon receiving an instruction (or command) from the external processor to open the switch.

[0064] In an embodiment, the integrated circuit further includes one or more of a low voltage power supply input, for example a 12 volt power supply input or a 24 V power supply input, a PWM generator, a timer unit, an NTC interface (negative temperature coefficient component) for measuring external temperature, a first communication interface for communicating with an airbag ECU, and a second communication interface for communicating with a controller of a battery management system (MBS).

[0065] Integrated circuits may be embedded in a semiconductor substrate and incorporated into a packaged semiconductor device (also referred to as a "chip").

[0066] According to another aspect, the present invention also provides a contactor including: a first power terminal, a second power terminal; a sub-circuit electrically connected between the first power terminal and the second power terminal and including at least three elements connected in series: a conductor portion, a main switch including a movable part driven by an actuator, and a fuse; a magnetic sensor configured to measure a primary current flowing through the conductor portion; and a controller communicatively connected to the magnetic sensor to measure the primary current flowing through the conductor portion and operably connected to the actuator for selectively opening and closing the main switch, the controller having a communication port connectable to an external processor (BMS, ECU) for receiving commands to open or close the switch.

[0067] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

[0068] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief explanation of the drawings]

[0069] [Figure 1] FIG. 1 shows a high level block diagram of a contactor and a power circuit including the contactor as proposed by the present invention. [Figure 2] FIG. 2 shows another block diagram of a contactor and a power circuit including the contactor as proposed by the present invention, which can be seen as a variation or specific implementation of the contactor and circuit shown in FIG. [Figure 3] FIG. 3 shows a typical time current curve that may be used in embodiments of the present invention to determine how much time is available to open a switch as a function of measured current. [Figure 4A]FIG. 4A shows a flowchart of a method according to an embodiment of the present invention that may be performed by a controller of the contactor shown in FIG. 1 or FIG. [Figure 4B] FIG. 4B shows a flowchart of a method according to an embodiment of the present invention that may be performed by a controller of the contactor shown in FIG. 1 or FIG. [Figure 4C] FIG. 4C shows a flowchart of a method according to an embodiment of the present invention that may be performed by a controller of the contactor shown in FIG. 1 or FIG. [Figure 4D] FIG. 4D shows a flowchart of a method according to an embodiment of the present invention that may be performed by a controller of the contactor shown in FIG. 1 or FIG. [Figure 5] FIG. 5 shows a block diagram of an integrated circuit including a processor that may be used in embodiments of the present invention. [Figure 6] FIG. 6 shows a block diagram of another integrated circuit including a processor that may be used in embodiments of the present invention.

[0070] The drawings are schematic only and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. Any reference signs in the claims shall not be construed as limiting the scope. In different drawings, the same reference signs refer to the same or similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0071] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are schematic only and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and relative dimensions do not correspond to actual reductions to practice of the invention.

[0072] Furthermore, terms such as first, second, etc. in the description and claims are used to distinguish between similar elements and not necessarily to describe a temporal, spatial, sequential, or any other manner of ordering. It will be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of application in orders other than those described or illustrated herein.

[0073] Furthermore, terms such as upper, lower, and the like in the description and claims are used for descriptive purposes and not necessarily to describe relative positions. The terms so used are interchangeable under appropriate circumstances, and it is understood that the embodiments of the invention described herein are capable of application in orientations other than those described or illustrated herein.

[0074] It should be noted that the term "comprising" used in the claims is not to be interpreted as being limited to the means listed thereafter, nor does it exclude other elements or steps. It is therefore to be interpreted as specifying the presence of the stated features, integers, steps, or components as they are mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" is not limited to a device consisting only of components A and B. It means that, in the context of the present invention, the relevant components of the device are only A and B.

[0075] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification may, but do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0076] Similarly, in the description of exemplary embodiments of the invention, it will be understood that various features of the invention may be grouped together in a single embodiment, figure, or description for the purpose of streamlining the disclosure and aiding in understanding one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

[0077] Furthermore, some embodiments described herein include some features but not other features included in other embodiments, meaning that combinations of features from different embodiments are within the scope of the invention and form different embodiments, as would be understood by one of ordinary skill in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0078] In the description provided herein, numerous specific details are set forth. However, it will be understood that embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0079] As used herein, the term "squib" refers to a small explosive device.

[0080] In this document, the expressions "primary current" and "HV current" mean the same thing.

[0081] In this document, the expressions "secondary current" and "current flowing through the actuator coil" mean the same thing.

[0082] As used herein, the terms "switch" or "HV switch" or "main switch" mean the same thing and refer to the switch connected between the first and second high power terminals (see switches 153, 253) unless it is clear from the context that another switch is meant (e.g., switch 265 for energizing a coil or switch 263 for blowing a fuse).

[0083] As used herein, the terms "period" or "time interval" or "duration" mean the same thing.

[0084] The present invention relates to a contactor for selectively connecting / disconnecting a battery of an electric or hybrid vehicle to / from an electrical load (e.g., an inverter, an electric motor, etc.). The present invention also relates to a power circuit including the contactor, a method for interrupting current flowing through the contactor, and an integrated circuit ideally suited for use in such a contactor.

[0085] US2014 / 292109A1 discloses a contactor including an electromechanical switch including a current sensor for measuring the current flowing through the contactor when the switch is closed. Whether the switch in this prior art contactor is open or closed is controlled by an external processor, often referred to as an electronic control unit (ECU).

[0086] However, to create a safe power system, it is not enough to have a contactor that can connect or disconnect the battery. Electrical circuits in electric vehicles can pose a real threat to passengers in the event of a collision, so for safety reasons, it is important to quickly detect malfunctions in the power circuits and, depending on the severity of the problem, quickly and reliably disconnect the battery, potentially within 5 ms.

[0087] The present invention provides a contactor including a first power terminal (e.g., connectable to a battery) and a second power terminal (e.g., connectable to an electrical load or a charging circuit), and at least three elements electrically connected in series between the first and second power terminals: a conductor portion (e.g., a busbar portion), a main switch including a moving part driven by an actuator, and a subcircuit including a fuse (e.g., a pyrofuse or squib), all of which are embedded in a housing of the contactor. The contactor further includes a magnetic sensor configured to measure a (primary) current (also referred to as "HV current") flowing through the conductor portion. The contactor further includes a controller (e.g., a programmable microcontroller) communicatively connected to the magnetic sensor for measuring the primary current flowing through the conductor portion. The controller is also operably connected to the actuator for selectively opening and closing the switch. The contactor further includes detection means for detecting whether the main switch is effectively open or closed (directly or indirectly, for example, by determining an electrical characteristic of the actuator).

[0088] According to an important aspect of the invention, the controller is further configured to (i) measure the primary current flowing through the conductive portion and detect an overcurrent condition, and if an overcurrent condition is detected, (ii) operate an actuator to open (or attempt to open) the main switch, and (iii) detect whether the switch is actually open, and if the controller detects that the switch is still closed (e.g., after a time interval Δt from the moment of operating the actuator), blow a fuse.

[0089] The main switch is preferably capable of conducting at least 100 amps of current.

[0090] The time interval Δt may be a predefined time interval or may be calculated (e.g., using a look-up table) as a function of the measured HV current. This period may be determined only once after measuring the HV current, or may be dynamically adjusted or updated (based on ongoing HV current measurements).

[0091] The advantage is that the controller inside the contactor can determine whether the main switch is actually open or not, and can therefore also detect if the switch did not open for whatever reason. This can happen, for example, if the switch contacts get stuck or welded to the busbar due to a current surge. In such a case, the controller will decide to blow the fuse to stop the current.

[0092] An advantage is that the magnetic sensor can measure HV current in a contactless manner. In this way, the contactor can have two voltage domains: a primary voltage domain, also referred to herein as the "high voltage domain", HV domain, operating for example at 60 volts or above, e.g., 120 volts or above or 200 volts or above, and a secondary voltage domain, also referred to herein as the "low voltage domain", LV domain, operating for example at 48 volts or below, e.g., 36 volts or below, e.g., 24 volts or below, e.g., 12 volts or below. The magnetic sensor may be physically located near the conductor portion (e.g., busbar portion), being part of the HV domain but operating in the LV domain, and preferably also thermally insulated from the conductor portion.

[0093] The main advantage is that the contactor can (itself) use the detection means to detect whether the switch is effectively open or closed.

[0094] The advantage is that the contactor can detect whether the switch is open or closed autonomously and without having to rely (or rely only on) measurements from a magnetic sensor (which may be broken or damaged) and / or without having to communicate with an external device (which may have a broken communication channel and / or introduce delays) and / or without having to use or rely on components external to the contactor. This provides redundancy (at a system level), thus improving the overall safety and reliability of the power system in which the contactor is used.

[0095] A key advantage is that by possibly and actually checking the switch status itself (inside the contactor), and / or by measuring the HV current itself (inside the contactor), and / or by determining the overcurrent condition itself (inside the contactor), the communication or feedback loop for a particular event is shortened (compared to a communication loop involving one or more communications with an external processor and / or components located outside the contactor). This shortened loop, in turn, provides extra time during which an attempt to open the switch can be made without having to blow a fuse, which would irreversibly damage the contactor. Thus, thanks to diagnostic capabilities within the contactor itself, the life of the contactor can be extended, for example, by avoiding blowing a fuse in situations where the current is small enough and / or there is enough time to safely open the switch.

[0096] In other words, the advantage of this contactor is that it can (under certain conditions) first attempt to open the switch in a reversible manner, which may not be possible if valuable time is lost due to communication with an external device. By shortening the communication or decision-making loop, the probability of having to blow a fuse in accordance with safety standards can be reduced.

[0097] An advantage is that the "detection means" provides a means of analyzing whether the switch is closed (which is a form of internal diagnostics) in a manner similar to the current measurement performed by the magnetic sensor. In this way, the reliability of the contactor can be increased, improving the safety of the power system in which the contactor is used. Surprisingly, it can also extend the life of the contactor, since without the detection means the only safe option would be to blow a fuse. In contrast, the contactor of the present invention can make better decisions to determine whether the current is small enough and / or there is enough time to attempt to open the switch, and if this is successful, there is no need to blow a fuse.

[0098] An advantage is that the fuse is also integrated into the contactor because the contactor housing provides protection for the fuse and for the interconnection between the controller and the fuse, thus reducing the risk of the fuse not blowing and further increasing the safety of the overall system.

[0099] In another or further embodiment, the controller may further include at least one (e.g., one or two) communication interfaces (e.g., one-way or two-way serial bus interfaces) connectable to an external processor (e.g., to an external ECU, e.g., to an airbag ECU, and / or to a battery management system controller) for sending and receiving information or instructions, e.g., to provide a signal indicative of a measured current and / or to receive one of the following commands: a command to open a switch (or to disconnect a battery), a command to close a switch (or to connect a battery), or a command to blow a fuse.

[0100] In such an embodiment, the opening of the switch may be triggered by one or more of the following events: A. detection of an overcurrent condition by the contactor itself, for example by comparing the measured current to a threshold or by using the classic I2T (ampere-squared-second) technique; or B. receipt of a command from an external processor, for example from an airbag controller, to disconnect the battery or open the switch.

[0101] However, other communications are possible, for example a contactor receiving a command to blow a fuse unconditionally, or a contactor reporting an abnormal HV current.

[0102] The present invention also provides a method for interrupting current flow through such a contactor, comprising the method steps (i)-(iii) described above, which method will be described in more detail when discussing Figure 4.

[0103] The present invention also provides an integrated circuit particularly adapted to carry out this method when incorporated into such a contactor, the integrated circuit preferably including non-volatile memory (e.g., flash) containing executable instructions for carrying out this method.

[0104] Now, referring to the figure.

[0105] 1 shows a high-level block diagram of a power circuit 100 including a battery 111 (e.g., a high-voltage battery providing a voltage of at least 100 volts, or at least 200 V) connected to an electric load 120 (e.g., an electric two-phase or three-phase motor or a charging circuit) via a contactor 150. The power circuit 100 may be incorporated into an electric vehicle (EV) or a hybrid vehicle (HV), e.g., a car. Of course, in practice, the power circuit 100 may include additional components, such as an inverter (not shown).

[0106] Although the contactor 150 of FIG. 1 includes a first power terminal 151a that is connected or connectable to the battery 111 and a second power terminal 151b that is connected or connectable to the electrical load 120, the contactor 150 can of course also be used in other power circuits.

[0107] The contactor 150 includes a subcircuit electrically connected between a first power terminal 151 a and a second power terminal 151 b and includes at least three elements connected in series: a conductor portion 154 (e.g., a busbar), a switch 153 (e.g., an electromagnetic switch), and a fuse 158 (e.g., a pyrofuse) or squib. The conductor portion 154 may be integrally formed with either the first power terminal 151 a or the second power terminal 151 b, although this is not absolutely required.

[0108] If fuse 158 is still intact and switch 153 is closed, the electrical path formed between first and second terminals 151 a, 151 b is continuous, i.e., the battery is connected to the electrical load. If switch 153 is open and / or fuse 158 is blown, the electrical path formed between first and second terminals 151 a, 151 b is open, i.e., the battery is disconnected from the electrical load.

[0109] The contactor 150 optionally further includes a controller 160, e.g., a programmable microcontroller, having a non-volatile memory 161, a timer unit, a PWM generator block, an analog-to-digital converter (ADC), a communication interface (e.g., a serial communication interface, e.g., a CAN interface), a clock generator (e.g., based on a crystal or an RC oscillator), etc. The controller 160 is powered by a low supply voltage, e.g., a second, battery, located outside the contactor and connected to the contactor, and is configured to provide a low-voltage power supply, e.g., 48 volts or less, or 36 volts or less, or 24 volts or less, e.g., about 12 volts. The low voltage is applied to the contactor via low-voltage terminals 152a, 152b. The controller may be powered directly by this low supply voltage or by a voltage derived from this low supply voltage, e.g., provided by one or more voltage regulators 162, if present. If present, the controller 160 and voltage regulators 162 may be mounted on a printed circuit board (PCB, not shown). The controller 160 may be part of an integrated circuit, a preferred embodiment of which is shown in FIG.

[0110] Contactor 150 further includes a housing (not explicitly shown, but indicated schematically by rectangle 150 with rounded corners). As illustrated, switch 153, fuse 158, and controller 160 are located inside the housing. This reduces the risk of not being able to blow the fuse in the event of an emergency, for example after a crash. Importantly, switch 153 and fuse 158 operate in a high-voltage domain, while controller 160 (and other components described further below) operate in a low-voltage domain that is galvanically isolated from the high-voltage domain.

[0111] The contactor further includes a magnetic sensor 155 configured to measure (in a contactless manner) the current flowing through the conductive portion 154. Magnetic current sensors are known in the art and therefore need not be described in full here. Suffice it to say, these magnetic current sensors may include at least one magnetic sensor element, such as a horizontal Hall element or a vertical Hall element oriented to measure the magnetic field generated by the current as it flows through the conductive portion 154, although other magnetic sensor structures may also be used, including, for example, a magnetoresistive (MR) element or at least two Hall elements spaced apart and oriented in the same direction, allowing for the magnetic field gradient to be determined. The use of a differential or gradient signal reduces the influence of external disturbance fields and therefore allows for the current flowing through the conductive portion 154 to be determined with improved accuracy. The magnetic sensor may include a magnetic flux concentrator.

[0112] The values ​​obtained from the magnetic sensor elements or from a magnetic sensor structure (e.g., a Wheatstone bridge) including the magnetic sensor elements may be amplified (e.g., using a differential amplifier) ​​and digitized (e.g., using an analog-to-digital converter ADC embedded in the controller 160). The current values, or a subset of the current values, may be transmitted to an external processor, e.g., an external ECU, via a communication bus, e.g., a CAN interface.

[0113] The magnetic sensor 155 may be embedded in the same silicon substrate as the controller 160, or may be located outside of but electrically connected to the controller 160. Preferably, the distance between the magnetic sensor 155 and the conductive portion 154 is relatively small (e.g., less than 10 mm) to ensure a sufficiently large signal. In certain embodiments, the contactor 150 may have multiple magnetic sensor elements located at some distance from the conductive portion 154. This allows for measuring current with a higher signal-to-noise ratio (SNR).

[0114] The switch 153 includes a moving part (not shown) that is driven by an actuator 156. The actuator 156 may be an electromagnetic actuator that includes a coil (schematically illustrated in FIG. 2) and a moving element disposed inside the coil (not shown). The actuator 156 may also include a mechanical spring (not shown) for biasing the switch 153 to a normally open (NO) state or a normally closed (NC) state. The moving element may be controlled, for example, by sending a secondary current (LV current) through the coil (e.g., as illustrated in FIG. 2). Such switches 153 and actuators 156 are well known in the art and therefore need not be described in further detail herein.

[0115] According to an important aspect of the present invention, the actuator 156 of the contactor 150 of the present invention includes a detection means 157 capable of detecting (directly or indirectly) whether the switch 153 is actually open or closed. Two possible implementations are described below, but the present invention is not limited thereto and other detection means are also contemplated. In a first implementation, the actuator 156 includes a coil and a shunt resistor connected in series with the coil; the voltage across the shunt resistor is measured; the voltage across the coil is measured and digitized; and the voltage signal is analyzed by the controller 160 (e.g., by software). In a second embodiment, the actuator 156 includes a coil and magnetic positioning means, such as a linear position detector or a magnetic presence detector, also known as a "proximity switch." The proximity switch may include a transmitting coil (for transmitting an RF signal) and a receiving coil (for receiving the RF signal), and a so-called "target" may be connected to a moving element to modulate the received signal. The controller 160 may analyze the receiver signal to determine the position of the target and, therefore, the state of the switch 153.

[0116] A major advantage of adding the detection means 157 internal to the contactor 150 is that the controller 160 can use the detection means 157 as a feedback means ("closed loop control") to determine whether the switch 153 is actually open or closed, independently of the signal obtained from the magnetic sensor 155, and without having to rely on a signal obtained from an external processor. Because the detection means is also integrated within the housing, the risk of malfunction due to, for example, signal disturbances or a lost communication link is greatly reduced.

[0117] It should be noted that the detection means 157 described herein can also be used for safety checking (at the system level), for example by testing whether a main switch is stuck open or stuck closed. This is possible even if two contactors according to the invention are connected in series between a battery and an electrical load and one of the main switches of these contactors is open. In that case, it is still possible to check whether the main switch of the other contactor is open or closed by using the detection means 157, rather than by measuring the primary current (which is zero).

[0118] The controller 160 also has an output port (eg, OUT2 in FIG. 5) that can trigger the fuse 158, for example, directly or via an optional actuation circuit 163.

[0119] Having described the various components of the contactor 150, the next section will explain how the contactor 150 proposed by the present invention may function.

[0120] As can be seen from FIG. 1 , during operation, HV battery 111 provides a voltage of at least 100 volts, low-voltage battery 140 provides a voltage of up to 48 volts, and external controller 130 (e.g., ECU) may provide a signal to controller 160 of contactor 150 to connect the HV battery or close switch 153 (or the like). Upon receiving such a command, controller 160 will operate actuator 156 (e.g., by energizing the coil) to close switch 153 and thereby allow primary current to flow through conductor portion 154. Optionally, upon receiving such a command, controller 160 may first perform an internal safety check (e.g., calculate a checksum of a portion of non-volatile memory or diagnose the coil) and operate actuator 156 if the safety check is successful. Actual control of the motor is external to contactor 150 and is outside the scope of this invention.

[0121] The external processor 130 may request the contactor 150 to measure the (primary) current flowing through the conductive portion 154. The controller 160 will obtain a signal (e.g., a voltage signal) from the magnetic sensor 155 and convert it into a current signal (e.g., amplify, digitize, and multiply by a constant K) in a manner known in the art. The constant K may be hard-coded or determined during a calibration step and subsequently stored in the non-volatile memory 161 of the contactor 150. Preferably, the measured signal is also temperature-compensated in a known manner. For this purpose, the contactor may further include a temperature sensor that may be placed near the magnetic sensor. In the integrated circuit of FIG. 5, both the magnetic sensor and the temperature sensor are integrated into the integrated circuit, but the invention is not limited thereto. The (optionally temperature-compensated) current value may be transmitted to the external processor 130 via an output port or via a serial bus interface, e.g., a CAN bus. Non-volatile memory 161 may be embedded within controller 160 , for example in the form of flash, or may be a separate component connected to controller 160 .

[0122] According to an important aspect of the present invention, the controller 160 of the contactor 150 is also configured to autonomously measure the HV current (without receiving a command to do so from an external processor), to detect an overcurrent condition itself, and / or to perform internal diagnostics. This may be based on a simple comparison of the measured current with a predefined threshold I1 (e.g., a parameter stored in non-volatile memory 161), or on the classical I2T (Ampere Squared Hours) approach, or on a combination of both, as will be further discussed with respect to FIG. 3. As explained above, if the controller detects an overcurrent condition, it will first attempt to open the switch, and if the switch does not open, will attempt to blow the fuse as described in steps (i)-(iii) above.

[0123] The external processor 130 may request the contactor 150 to disconnect from the HV battery (or open the switch 153). A classic contactor would simply operate the actuator 156 to open the switch 153 (in an open-loop fashion), but would not know if the switch actually opened. The external processor may request a new current measurement, and if it sees that the current does not drop, it may send a new request to the contactor to open the switch 153, which may fail again until someday the external processor commands another component to blow a fuse. This is not ideal and may require an excessive amount of time, which could lead to a dangerous situation.

[0124] As another example, assume that external processor 130 is an airbag ECU and a crash occurs that deploys the airbag. If such an event occurs, the airbag ECU may send a command to unconditionally blow a fuse as a safety precaution.

[0125] The inventors of the present invention have recognized that these prior art solutions are not ideal, and that there may be situations where it is possible to open a switch instead of blowing a fuse, provided that it is guaranteed that the switch is effectively open. If this were possible, it would be possible to extend the life of the contactor, provided that safety was guaranteed. This is the key insight underlying the present invention.

[0126] The contactor 150 proposed herein ensures that the HV current is interrupted, but only blows the fuse when absolutely necessary. More specifically, when the controller 160 receives a command from an external processor to "interrupt the current flow" (or to "disconnect the battery" or to "open the switch," etc.), the controller 160 will first attempt to open the switch, and if the attempt fails or if there is insufficient time, will autonomously blow the fuse. This will be explained in more detail when discussing the method of FIG. 4.

[0127] Although not explicitly shown in FIG. 1, contactor 150 may optionally further include a magnetic shield to reduce magnetic disturbances caused by an actuator coil (if present) on magnetic sensor 155.

[0128] The controller 160 and / or the printed circuit board on which the controller 160 may be mounted is electrically isolated (galvanically isolated) from the HV region, in particular the conductor portions 154 (e.g., busbar portions), or preferably also thermally isolated from the HV region.

[0129] The contactor may measure the HV current at a relatively high first sampling rate (e.g., a rate of 1 kHz to 10 kHz) for diagnostic purposes, and a sub-sampled version of the HV current may be provided to an external ECU, for example, a battery management system controller (e.g., at a rate of 100 Hz to 500 Hz).

[0130]

[0023] Figure 2 shows a block diagram of a contactor 250 and power circuit 200 including at least one such contactor, which may be considered a variation or specific implementation of the contactor 150 and power circuit 100 of Figure 1. Like elements are designated with like reference numerals. The main differences between the block diagram of Figure 2 and the block diagram of Figure 1 are as follows: The actuator 256 of the contactor 250 shown in FIG. 2 is an electromagnet including a coil; the detection means 257 of the contactor 250 include a shunt resistor 264, Detecting whether the switch is open or closed can be performed by applying a known waveform, for example a step function (i.e. a waveform that changes sharply from logic "0" to logic "1") or a pulse width modulated signal (PWM), to the coil and by measuring and sampling the (first) voltage across the shunt resistor 264, and optionally also by measuring and sampling the voltage across the coil (or the voltage across the series connection of the coil and the shunt resistor, or the voltage across the second switch 265 (e.g. a transistor), from which the voltage across the coil can be derived), and by analyzing the first and second voltage waveforms (e.g. by looking at some parameters such as the time constant, or the shape of the waveform). This analysis may be based on a model of an RLC circuit with a moving element. In addition, the detection of whether the switch is open or closed may also take into account the value obtained from the magnetic sensor (indicative of the HV current flowing through the conductive part), if this current is different from zero. The controller 260 of the contactor 250 shown in Fig. 2 has at least one, for example two, communication ports, for example two serial communication ports. In the particular example shown in Fig. 2, the first communication port is used or can be used to communicate with the general ECU or the airbag ECU 230, and the second communication port is used or can be used to communicate with the controller 213 of the battery management system (BMS) 212. The controller 260 is preferably integrated into an integrated circuit or semiconductor chip, e.g., a packaged semiconductor device. The chip may be configured to be powered directly or indirectly from a 5V power supply, or to be powered directly or indirectly from a 12V power supply. The magnetic sensor 255 may be or include at least one Hall element or at least one magnetoresistive (MR) element, and is preferably integrated into the integrated circuit or inside the same packaged device. The contactor 250 may further include a "fuse activation circuit" 263, illustrated here schematically by a switch symbol. In practice, this may be, for example, a transistor or a dedicated fuse driver chip (e.g., known as a "squib driver").

[0131] The controller 260 may be mounted on a printed circuit board (not shown), which is mounted inside the contactor 250 and is electrically and preferably also thermally isolated from the HV domain.

[0132] In a variation of Figure 2, the power circuit has at least two contactors, for example two contactors connected in series or two contactors connected in parallel, or one contactor in the path from the battery to the load and another contactor in the return path from the load to the battery.

[0133] 3 shows an exemplary "time-current curve" that may be used in embodiments of the present invention to determine, for example, how much time Δt is available to attempt to open switch 153, 253 as a function of measured HV current flowing through conductor portion 154, 254. Such a graph may be specific to a particular vehicle type and may depend on the dimensions of the busbar network, thermal limitations of the powertrain modules, etc. The graph may also be taken as a given for a particular project. The values ​​of this graph may be stored in the controller's non-volatile memory in any suitable manner (e.g., as a table, or as a piecewise linear curve, or as a set of parameters in an algebraic expression, or in any other suitable manner).

[0134] As mentioned above, the controllers 160, 260 of the contactors 150, 250 can measure, on demand or autonomously, the HV current flowing through the conductive portions 154, 254. Depending on the particular implementation of the switch and / or actuator and / or low voltage power supply, it typically takes a finite time Δtreq (time required) to open the switch under normal circumstances (i.e., assuming no moving parts are stuck), e.g., about 90 ms for certain types of switches, although of course the invention is not limited in this respect.

[0135] If the controller measures the HV current, and if this measured current is greater than the value Imax (see FIG. 3), the controller knows that there is no time to further attempt to open the switch, and therefore the controller will immediately blow the fuse. If the measured current is less than Imax, the maximum time to allow this current to flow is shown in the graph. For example, if the measured current is equal to i1, the maximum time is t1. If the maximum allowed time is less than the time typically required (depending on the implementation) to open the switch or to perform a safety check and open the switch (e.g., 90 ms as mentioned above), then it is also not worth further attempting to open the switch, and the controller will immediately blow the fuse. However, if the measured HV current is equal to i2, then the maximum time is t2, and if this time is greater than the time typically required to open the switch, optionally preceded by the safety check in question (e.g., greater than the 90 ms mentioned above), then it makes sense to first try to open the switch in a reversible manner using the actuator, and only if it turns out that the switch cannot be opened, or cannot be opened within the expected period of time, will the controller decide to blow the fuse after all. In this way, the controller of the present invention can maximize the life of the contactor while ensuring safety.

[0136] Of course, the 90ms value is only an example and other switches and actuators can be used, but the same principles apply.

[0137] Figure 4A shows a flow chart of a method 400 for interrupting current flowing through a contactor 150, 250 such as those shown in Figure 1 or Figure 2. The method 400 includes the following steps. a) step 401 of measuring at least once or repeatedly the current flowing through the conductive portion 154, 254 of the contactor 150, 250; b) detecting 403 an overcurrent condition (based on one or more measured current values); c) step 406 of determining the time Δtav available for opening the primary switch 153, 253 and optionally performing a safety check based on the measured current value, for example taking into account the time typically required to open the switch and / or to perform a safety check, for example taking into account a current versus time table or a curve or a mathematical formula; d) comparing the available time Δtav with the typically required time Δtreq (407); If the available time Δtav is less than the required time Δtreq, continue with step g); otherwise, continuing with step e); e) step 408 of operating the actuator 156, 256 to open (or attempt to open) the switch 153, 253; f) detecting using detection means 157, 257 whether the switch 153, 253 is effectively open within the available time period Δtav; a step 409 of continuing with step g) if the switch 153, 253 is still closed after the available time period Δtav; g) blowing a fuse, step 412;

[0138] The advantage is that the controller performs step 403 (determining an overcurrent condition) because this automatically triggers the opening of the switch and / or blowing of the fuse sooner (e.g., before an external processor detects that something is wrong), thereby avoiding or reducing the risk of damaging the vehicle and / or endangering the lives of its occupants. Faster detection also increases the probability of surviving the fuse.

[0139] Method 400 describes a relatively simple procedure and shows the most important steps proposed by the present invention, although many variations of this method are possible.

[0140] 4A, steps c) and d) are omitted, the branch to blow the fuse is omitted, and the timeout value of step 410 is predefined (e.g., hard-coded). In such an embodiment, the contactor, assuming it is in step a), measures the current, and if an overcurrent is detected in step b), the contactor will first attempt to open the main switch in steps e) and f), evaluating whether the main switch is actually open after the predefined timeout period. If the main switch is not open, the contactor will blow the fuse.

[0141] 4B shows a flowchart of method 410, which is a further variation of the methods described hereinabove, in which, assuming that after detecting that an overcurrent condition has occurred (or as part of one), the contactor tests (at step 414) whether the measured primary current is greater than a predefined (critical) threshold, and if so, the contactor will blow the fuse (at step g). If not, the contactor will first attempt to open the main switch in steps e) and f), and after a predefined timeout period ΔT (at step 410), evaluate whether the main switch is actually open. And if the main switch is not open, the contactor will blow the fuse (step g).

[0142] Figure 4C shows a flowchart of a method 420 for interrupting current flowing through contactors 150, 250, which can be considered another variation of method 400 of Figure 4A. The most significant difference between method 420 of Figure 4C and method 400 of Figure 4A is that it includes step 413, which tests whether the time that has elapsed since the overcurrent condition was detected in step b) is greater than the available time Δtav, and if not, returns to step c) and updates the available time Δtav.

[0143] An advantage of this method 410 is that the available time Δtav is updated at least once, e.g., dynamically updated, taking into account recent measurements of the primary current (in step a), and therefore effectively taking into account fluctuations in the primary current while attempting to open the switch.

[0144] 4D shows a flowchart of a method 430 for interrupting current flowing through contactors 150, 250, which can be considered another variation of the method 400 of FIG. 4A. The most significant difference between the method 430 of FIG. 4D and the method 400 of FIG. 4A is that that attempts to open the switch can be triggered not only by overcurrent detection in the controller itself, but also by a command to open the switch (or to disconnect the battery, etc.) coming from a controller or processor or ECU located outside the contactor; and The contactor's controller may also blow the fuse after receiving 405 a command to unconditionally blow the fuse coming from a controller or processor or ECU located external to the contactor.

[0145] Steps 401, 403, 405, and / or 402 may be performed in parallel or semi-parallel, eg, in a time-multiplexed manner.

[0146] 4A-4D show four examples of methods that may be performed by the contactor controller proposed herein, although of course other variations are possible in practice.

[0147] As mentioned above, testing or evaluating or assessing 409 whether the main switch 153, 253 is actually open can be performed indirectly by evaluating the state of the actuator. The state of the actuator can be determined, for example, by measuring and analyzing the actuator's current waveform (e.g., using a shunt resistor) to detect whether the moving element has actually moved. The state of the actuator can also be determined by using a position sensor (e.g., a magnetic position sensor or a proximity sensor) or in any other suitable manner.

[0148] "Step 409 of detecting if the switch is open may include measuring the voltage across the shunt resistor and / or the voltage across the coil (or the coil in series with the switch, or the coil in series with the shunt), and may therefore involve multiple voltage measurements. These two voltages may be measured and sampled using a time-multiplexed scheme and a single or two analog-to-digital converters (ADCs).

[0149] Of course, the controllers 160, 260 of the contactors 150, 250 may also be configured to, e.g. It may perform other tasks (not shown in FIGS. 4A-4D ), such as periodically transmitting the measured current values ​​to an external processor, for example, to a battery disconnect unit (BDU), sometimes referred to as a battery junction box (BJB) or power relay assembly (PRA). As noted above, the rate at which the current values ​​are transmitted may be less than the rate at which the primary current is measured and may be used internally to assess an overcurrent condition.

[0150] FIG. 5 shows a block diagram of an integrated circuit 500 that may be used in embodiments of the present invention.

[0151] The integrated circuit 500 of FIG. - a controller in the form of a programmable processor, e.g. a programmable microcontroller or a digital signal processor (DSP), a magnetic sensor, e.g., a circuit including one or more horizontal Hall elements, one or more vertical Hall elements, a magnetoresistive (MR) element, and optionally an integrated flux concentrator (IMC); a shunt interface for sensing a voltage across a shunt resistor connectable to an integrated circuit, from which a secondary current (or LV current) can be derived; a voltage sensing interface for sensing the voltage across the coil, connectable to the integrated circuit (e.g., as shown in FIG. 2); a first output OUT1 for driving the actuators 156, 256, optionally using a PWM signal; a second output OUT2 for activating or triggering a fuse driver, for example a pyrofuse driver, - executable instructions for a controller, i) using said magnetic sensor to measure 401 the primary current to detect 403 whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continuing with step ii), otherwise repeating step i); ii) asserting the first output OUT1 to operate the actuator 408 to open the main switch 153, 253; iii) A non-volatile memory containing instructions for detecting 409 whether the main switch 153, 253 is effectively open by analyzing the signals obtained from the shunt interface and the signals obtained from the voltage sensing interface, and asserting a second output OUT2 to blow 412 the fuse 158, 258 if it is detected that the main switch is still closed after a certain time interval (e.g., Δtav).

[0152] The non-volatile memory may also contain data corresponding to a current versus time curve.

[0153] Although the "Shunt Interface," and "Voltage Sense Interface," and "Power Supply Voltage Interface" are shown with six terminals (or pins), this is not absolutely required, as some signals may be shared with the "Ground Terminal" in a manner known in the art.

[0154] The integrated circuit 500 may further include one or more of a clock generator (e.g., quartz-based or based on an RC oscillator), a voltage regulator, a timer unit, an analog multiplexer, e.g., a pulse width modulation (PWM) generator block connectable to the first output OUT1, a digital communication interface for receiving instructions from an external processor, an analog-to-digital converter (ADC) configured to digitize signals obtained from the shunt interface and obtained from the voltage sensing interface, a 12 volt power supply input, a timer unit, an NTC interface (negative temperature coefficient component) for measuring the external temperature, a temperature sensor for measuring or estimating the temperature of the magnetic sensor.

[0155] FIG. 6 shows a block diagram of an integrated circuit 600 that can be seen as a variation of the integrated circuit 500 of FIG. 5, having a coil interface circuit that includes an integrated shunt resistor and a coil interface circuit that comprises an integrated transistor for controlling the flow of current through the coil.

Claims

1. A contactor (150, 250) comprising: a first power terminal (151a, 251a); a second power terminal (151b, 251b); a subcircuit electrically connected between the first power terminal and the second power terminal, the subcircuit including at least three elements connected in series: a conductor portion (154, 254), a main switch (153, 253), and a fuse (158, 258); a sub-circuit in which the main switch includes a moving part driven by an actuator (156, 256); a magnetic sensor (155, 255) configured to measure a primary current flowing through the conductive portion (154, 254); a controller (160, 260) communicatively connected to the magnetic sensor (155, 255) for measuring the primary current flowing through the conductor portion (154, 254) and operatively connected to the actuator (156, 256) for selectively opening and closing the main switch (153, 253); the contactor (150, 250) further comprises detection means (157, 257) for detecting whether the main switch (153, 253) is actually open or closed; The controller (160, 260) i) measuring 401 the primary current and detecting 403 whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continuing with step ii); ii) operating (408) the actuator (156, 256) to open the main switch (153, 253); iii) a contactor (150, 250) configured to detect (409) whether the main switch (153, 253) is effectively open and to blow (412) the fuse (158, 258) if it is detected that the main switch is still closed.

2. The controller: a) repeatedly measuring (401) a primary current flowing through the conductive portion (154, 254) using the magnetic sensor (155, 255); b) detecting (403) whether an overcurrent condition has occurred based on the measured primary current, and if an overcurrent condition is detected to have occurred, continuing with step c); c) determining (406) the time period (Δtav) available to open the main switch (153, 253); d) comparing (407) the available period (Δtav) with the period (Δtreq) required to open the main switch (153, 253), and if the available period is less than the required period, continuing with step g), otherwise continuing with step e); e) actuating (408) the actuator (156, 256) to open the main switch (153, 253); f) detecting (409) whether said main switch (153, 253) is effectively open, and continuing with step g) if said main switch (153, 253) is still closed after said available time period (Δtav); g) blowing (412) the fuse (158, 258).

3. the controller (160, 260) has at least one communication port connectable to an external processor (130, 213, 230); the controller (160, 260) is further configured to receive at least one command selected from the group consisting of a command to close the main switch, a command to open the main switch, and a command to blow the fuse; The controller: x) operating said actuator (156, 256) to close said main switch (153, 253) upon receiving a command to close said main switch; y) performing steps ii) and iii) upon receiving a command to open said main switch; z) blowing the fuse upon receiving a command to blow the fuse.

4. the contactor is capable of conducting at least 60 amperes of current; The contactor (150, 250) of any one of claims 1 to 3, wherein the contactor further comprises third and fourth power terminals (152a, 152b; 252a, 252b) for receiving a voltage source of up to 48 volts.

5. The contactor (150, 250) of any one of claims 1 to 4, wherein the fuse is or comprises a pyrofuse or a squib.

6. The contactor (150, 250) of any one of claims 1 to 5, wherein the actuator (156, 256) comprises a coil and a movable element movable relative to the coil.

7. the controller is further configured to measure a secondary current flowing through the coil; 7. The contactor (150, 250) of claim 6, wherein the controller is further configured to determine the primary current based on a signal obtained from the magnetic sensor (155, 255) and taking into account the secondary current to reduce an effect of a magnetic field generated by the secondary current.

8. the detection means (157, 257) comprises a shunt resistor (264) configured to measure the current flowing through the actuator (156, 256); the controller (160, 260) is further configured to measure a voltage across the shunt resistor (264) to determine a current flowing through the shunt resistor (264) and through the coil (256); 8. The contactor (150, 250) of claim 6 or 7, wherein the controller (160, 260) is further configured to repeatedly sample the current flowing through the shunt resistor (256) to thereby obtain a current waveform, and to analyze the current waveform to detect characteristics indicative of movement of the movable element.

9. the detecting means (157, 257) comprises a position sensor for detecting the position of the movable element; The contactor (150, 250) of any one of claims 6 to 8, wherein the controller (160, 260) is connected to the position sensor to determine the position of the moving element, thereby determining the status of the main switch.

10. the magnetic sensor (155, 255) is disposed in the vicinity of the conductive portion (154, 254) and includes at least one horizontal Hall element, at least one vertical Hall element, or at least one magnetoresistive element configured to measure a magnetic field component generated by a current flowing through the conductive portion; Alternatively, the magnetic sensor (155, 255) comprises at least two horizontal Hall elements or at least two vertical Hall elements spaced apart from each other and oriented parallel to each other and configured to measure a magnetic field difference or a magnetic field gradient.

11. further comprising an accelerometer and / or gyroscope connected to said controller (160, 260); the controller (160, 260) is further adapted to determine an abnormal condition based on signals obtained from the accelerometer and / or the gyroscope; The contactor (150, 250) of any one of claims 1 to 10, wherein the controller (160, 260) is further configured to autonomously open the main switch (153, 253) and / or blow the fuse (158, 258).

12. the controller (160, 260) is implemented in an integrated semiconductor device; the magnetic sensor (155, 255) is also integrated into the integrated semiconductor device; the actuator (156, 256) includes a coil connected in series with a second switch (265); the detecting means (157, 257) includes a shunt resistor (264) connected in series with the coil; the controller (160, 260) is configured to sample a first voltage across the shunt resistor (264) and to sample a second voltage across the coil or across a series connection of the coil and the shunt resistor, and to determine a status of the main switch (253) based on the samples of the first and second voltages; the controller (160, 260) has a first output (OUT1) for controlling the actuator for operating the main switch; The contactor (150, 250) of any one of claims 1 to 11, wherein the controller has a second output (OUT2) for blowing the fuse (158, 258).

13. An integrated circuit for use in a contactor (150, 250) according to any one of claims 1 to 12, comprising: said controller in the form of a programmable processor; the magnetic sensor; a shunt interface for sensing a voltage across a shunt resistor connectable to the integrated circuit, the shunt interface being capable of determining a secondary current from the voltage; a first output (Output 1) for driving an actuator connected to the main switch (153, 253); a second output (Output 2) for activating a fuse driver; the processor: i) measuring 401 the primary current using said magnetic sensor to detect 403 whether an overcurrent condition has occurred, and if an overcurrent condition is detected, continuing with step ii), otherwise repeating step i); ii) asserting the first output (Output 1) to operate (408) the actuator (156, 256) and open the main switch (153, 253); iii) an integrated circuit configured to detect (409) whether the main switch (153, 253) is effectively open by analyzing the signal obtained from the shunt interface, and to assert (412) the second output (Output 2) to blow (412) the fuse (158, 258) if it is detected that the main switch is still closed after a certain time interval (Δtav).

14. further comprising a digital communications interface for receiving instructions from an external processor; 14. The integrated circuit (500) of claim 13, wherein the processor is further configured to perform steps ii) and iii) upon receiving an instruction to open the main switch from the external processor.

15. The characteristic is, 12 volt power input, a PWM generator connectable to said first output; Timer unit, a negative temperature coefficient (NTC) component interface for measuring external temperature; a first communication interface for communicating with the airbag ECU; and a second communication interface for communicating with a controller of a battery management system (MBS).

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