Contactor, integrated circuit, and method of interrupting current flow

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 generally relates to the field of power circuits, and more specifically to contactors, integrated circuits, and methods for selectively connecting and disconnecting a battery of an electric vehicle or a hybrid vehicle to / from an electrical load and interrupting the flow of current.

Background Art

[0002] The motor of an electric vehicle (EV) or a hybrid vehicle (HV) can be powered by a battery that provides a voltage in the range of about 200 volts to about 800 V, or even higher. The battery can be capable of providing a current having a magnitude of up to about 1500 amperes, with current peaks up to 3000 amperes or even higher. Needless to say, the power circuit of such a vehicle poses a potential threat to passengers. For safety reasons, faults in the power circuit and / or the battery itself should be detected and repaired promptly. For example, some faults need to be detected within 5 ms.

[0003] In such vehicles, typically, under normal circumstances, a contactor is used to selectively connect and disconnect the battery to / from the electric motor or to / from the charging circuit. The power circuit may further include a fuse for opening the circuit in an emergency, for example, in case 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 a hybrid vehicle (HV).

[0005] There is always room for improvement or alternatives.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] One object of embodiments of the present invention is to provide a contactor for use in electric vehicles or hybrid vehicles, particularly electric vehicles and / or hybrid vehicles.

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

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

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

[0011] One object of the embodiments of the present invention is to provide a contactor having a switch, which is further capable of measuring and interrupting a current.

[0012] One object of embodiments of the present invention is to provide a contactor that has improved reliability (in the sense that it can stop the flow of current) and / or improved lifespan, preferably both.

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

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

[0015] These and other objectives are achieved by contactors, by power circuits, by methods for interrupting current flowing through contactors, and by integrated circuits according to embodiments of the present invention.

[0016] According to a first aspect, the present invention relates to a contactor comprising a first power terminal, a second power terminal, and a subcircuit electrically connected between the first and second power terminals and connected in series, comprising at least three elements: a conductive portion, a main switch (also referred herein as a “high voltage switch” or “HV switch”), and a fuse, wherein the main switch comprises a movable portion driven by an actuator, a magnetic sensor configured to measure a primary current (also referred herein as a “high voltage current” or “HV current”) flowing through the conductive portion, and a device communicatively connected to the magnetic sensor to measure the primary current flowing through the conductive portion, and the switch A contactor comprising a controller operably connected to an actuator for selective opening and closing, further comprising detection means for detecting whether a main switch is actually open or closed, wherein the controller is configured to (i) measure a primary current and detect whether an overcurrent condition has occurred, and if an overcurrent condition is detected, proceed to step ii), otherwise repeat step i), (ii) operate the actuator to open the main switch, and (iii) detect whether the main switch is effectively open and blow the fuse if it is detected that the main switch is still closed (e.g., after a time interval Δt).

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

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

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

[0020] The primary advantage is that the contactor can detect itself, using the detection means, whether the switch is effectively open or closed, without needing to communicate with an external device and without relying on measurements from a magnetic sensor. This is because it shortens the feedback loop and provides extra time to attempt to open the switch using the actuator without needing to blow the fuse. In other words, the advantage of this contactor is that (for example, under certain conditions where the HV current is below a certain value) it can first attempt to open the switch in a reversible manner, 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 the fuse due to insufficient time can be reduced.

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

[0022] The detection of an overcurrent condition may include comparing the measured HV current to a pre-defined value, or may include or be based on a classical I2T (ampere squared second) method.

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

[0024] An advantage is that the fuse is connected in series with the main switch, because this allows the HV current to be interrupted even if the main switch is not opened.

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

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

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

[0028] As described above, the opening of the switch can be, or will be, triggered by the reception of a corresponding command from (at least) an external processor (e.g., an 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 the following: (x) when receiving a command to close the switch, operate an actuator to close the main switch; (y) when receiving a command to open the switch, perform steps ii) and iii); (z) when receiving a command to blow the fuse, blow the fuse.

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

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

[0032] This voltage is referred to herein as the “low-voltage power supply.” This low voltage is not intended to power the vehicle’s motor, but may be supplied by a second battery intended to power the control circuitry. At a minimum, the controller, actuators, sensing means, and magnetic sensors are powered by the low-voltage power supply.

[0033] The high-voltage and low-voltage regions are galvanically separated. Preferably, the magnetic sensor is physically located in the immediate vicinity of the conductive portion, but the advantage of using a magnetic sensor that is galvanically separated from it is that this magnetic sensor allows the circuit mechanism in the low-voltage region to measure the current flowing into the high-voltage region, i.e., through the conductive portion.

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

[0035] In the 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 the embodiment, the controller is further configured to measure a secondary current flowing through a coil, and the controller is further configured to determine a primary current based on a signal obtained from a magnetic sensor and taking the secondary current into consideration.

[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 a secondary current value obtained by multiplying the primary current value by a predefined constant. In this way, the current flowing through the conductive part can be measured accurately while simultaneously enabling a compact design (the magnetic sensor and coil may be relatively close to each other, and magnetic shielding is not absolutely necessary).

[0038] In the embodiment, the detection means includes a shunt resistor configured to measure the current flowing through the actuating means, 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 to obtain a current waveform, and to analyze this current waveform to detect characteristics indicating the movement of the movable element.

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

[0040] In the embodiment, the magnetic sensor includes at least one horizontal Hall element, or at least one vertical Hall element, or at least one magnetoresistive element, which is positioned near the conductive portion and configured to measure the magnetic field component generated by the current flowing through the conductive portion.

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

[0042] A magnetic shield may be provided near the magnetic sensor to reduce the influence of external disturbances or actuator coils.

[0043] In the embodiment, the magnetic sensor includes at least two horizontal Hall elements or at least two vertical Hall elements that are spaced apart from each other, oriented parallel to each other, and configured to measure a magnetic field difference or magnetic field gradient.

[0044] In this embodiment, the controller can determine that the current flowing through the conductive portion is proportional to the magnetic field difference or magnetic field gradient. The advantage of using the magnetic field gradient is that it can reduce the magnetic field disturbance.

[0045] In the embodiment, the contactor further includes a temperature sensor mounted near the magnetic sensor (e.g., integrated on the same semiconductor substrate) to measure 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 the embodiment, the contactor further includes an accelerometer and / or gyroscope connected to a controller, the controller further adapted to determine abnormal conditions (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 gyroscope, and the controller further configured to autonomously open a main switch and / or blow a fuse when an abnormal condition is detected, for example by analyzing certain parameters (e.g., acceleration parameters or orientation parameters).

[0047] In the embodiment, the controller is mounted on an integrated semiconductor device, the magnetic sensor is also integrated on the semiconductor device (for example, as a separate component on a lead frame in the same packaged device, 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 a second voltage across the coil or across the series connection between 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 an actuator to operate the main switch, and the controller has a second output for blowing a fuse.

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

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

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

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

[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 via the communication port. 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] In another aspect, the present invention also provides a method for interrupting a current flowing through a contactor according to the first aspect, each step comprising: (i) measuring the primary current flowing through a conductive portion to detect whether an overcurrent condition has occurred; if an overcurrent condition is detected, proceeding to step ii); otherwise, repeating step i); ii) operating an actuator to open or attempt to open a main switch; and iii) detecting whether the main switch is effectively open and blowing a fuse if it is detected that the main switch is still closed after a certain time interval (Δtav).

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

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

[0057] In another aspect, the present invention also provides an integrated circuit for use in a contactor according to the first aspect, the integrated circuit comprising: a controller in the form of a programmable processor; a magnetic sensor (for example, 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 a secondary current can be determined; a voltage sensing interface for sensing a voltage across a coil; a first output for driving an actuator connected to a main switch; and a second output for activating a fuse driver (for example, a pyro-fuse driver). 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, proceed to step ii), otherwise repeat step i), ii) assert a first output to open the main switch or to operate an actuator to attempt to open it, and iii) detect whether the main switch is effectively open by analyzing the signal obtained from the shunt interface and the signal obtained from the voltage sensing interface, and if it is detected that the main switch is still closed after a certain time interval, assert a second output to blow the fuse.

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

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

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

[0061] The voltage sensing 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 non-volatile memory embedded in or connected to the processor. The non-volatile memory may include data corresponding to a current-vs-time curve. The non-volatile memory also preferably includes a computer program or code fragment that, when executed by a programmable processor, includes executable instructions for performing one of the methods described above, or some or all of the method steps described above.

[0063] In the 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) when it receives an instruction (or command) from the external processor to release a switch.

[0064] In the embodiment, the integrated circuit further includes one or more of the following: a low-voltage power input, e.g., a 12-volt power input or a 24-volt power 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 battery management system (MBS) controller.

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

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

[0067] Specific and preferred embodiments of the present invention are described in the appended independent and dependent claims. Features from the dependent claims are not merely expressly described in those claims, but may be combined as appropriate with features of the independent claims and other dependent claims.

[0068] These and other aspects of the present invention will be evident from the embodiments described below and will be illustrated by reference thereto. [Brief explanation of the drawing]

[0069] [Figure 1] Figure 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] Figure 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 modified example or specific implementation of the contactor and circuit shown in Figure 1. [Figure 3] Figure 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 the switch as a function of the measured current. [Figure 4A]Figure 4A shows a flowchart of a method according to an embodiment of the present invention, which can be performed by the contactor controller shown in Figure 1 or Figure 2. [Figure 4B] Figure 4B shows a flowchart of a method according to an embodiment of the present invention, which can be performed by the contactor controller shown in Figure 1 or Figure 2. [Figure 4C] Figure 4C shows a flowchart of a method according to an embodiment of the present invention, which can be performed by the contactor controller shown in Figure 1 or Figure 2. [Figure 4D] Figure 4D shows a flowchart of a method according to an embodiment of the present invention, which can be performed by the contactor controller shown in Figure 1 or Figure 2. [Figure 5] Figure 5 shows a block diagram of an integrated circuit including a processor that may be used in embodiments of the present invention. [Figure 6] Figure 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 and non-limiting. In the drawings, the sizes of some elements may be exaggerated for illustrative purposes and may not be drawn to scale. Any reference numerals in the claims are not to be construed as limiting. In different drawings, the same reference numeral refers to the same or similar elements. [Modes for carrying out the invention]

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

[0072] Furthermore, terms such as "first," "second," etc., in the description and claims are used to distinguish similar elements and are not necessarily used to describe temporal, spatial, sequential, or any other form of order. Terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that embodiments of the invention described herein may be applied in any order other than those described or illustrated herein.

[0073] Furthermore, terms such as "top," "bottom," etc., in the description and claims are used for descriptive purposes and are not necessarily used to describe relative positions. Terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that embodiments of the invention described herein may be applied in orientations other than those described or illustrated herein.

[0074] It should be noted that the term “including” as used in the claims is not to be construed as being limited to the means enumerated thereafter, nor does it exclude other elements or steps. Therefore, it is construed as specifying the presence of the described features, integers, steps, or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Accordingly, the scope of the expression “device including means A and B” is not limited to a device consisting solely of components A and B. It means, with respect to the present invention, that the relevant components of the device are only A and B.

[0075] Throughout this specification, any reference to “one embodiment” or “embodiment” means that any particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of the present invention. Therefore, occurrences of the phrase “in one embodiment” or “in an embodiment” in various places throughout this specification may refer to the same embodiment, though not all of them necessarily refer to the same embodiment. Furthermore, any particular feature, structure, or characteristic may be combined in any preferred manner in one or more embodiments, as would be apparent to those skilled in the art from this disclosure.

[0076] Similarly, in the description of exemplary embodiments of the present invention, various features of the invention may be grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various embodiments of the invention. However, this method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than those explicitly enumerated in each claim. Rather, as reflected in the claims below, the embodiments of the invention consist of fewer features than those of a single, aforementioned disclosed embodiment. Thus, the claims following the detailed description are explicitly incorporated into this detailed description, and each claim exists independently as a distinct embodiment of the invention.

[0077] Furthermore, some embodiments described herein include some features included in other embodiments, but do not include other features, and combinations of features of different embodiments are within the scope of the invention and form different embodiments, as will be understood by those skilled in the art. For example, any combination of any of the claimed embodiments may be used in the following claims.

[0078] Numerous specific details are described in the description provided herein. However, it is understood that embodiments of the present invention may be carried out without these specific details. In other instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0079] In this book, the term "squib" refers to a small detonator device.

[0080] In this book, the terms "primary current" and "HV current" refer to the same thing.

[0081] In this book, the terms "secondary current" and "current flowing through the actuator coil" refer to the same thing.

[0082] In this book, the terms “switch,” “HV switch,” or “main switch” mean the same thing, and they 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 (e.g., switch 265 for energizing the coil, or switch 263 for blowing the fuse) is meant.

[0083] In this book, the terms "period," "time interval," or "duration" all mean the same thing.

[0084] The present invention relates to a contactor for selectively connecting / disconnecting the 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 a contactor, a method for interrupting the 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 that includes a current sensor for measuring the current flowing through the contactor when the switch is closed. Whether the switch of the contactor in this prior art is open or closed is controlled by an external processor, often referred to as an electronic control unit (ECU).

[0086] However, simply having contactors that can connect or disconnect batteries is not enough to create a safe power system. Because the electrical circuits of electric vehicles can pose a real threat to occupants, such as in the event of a collision, for safety reasons, it is best to quickly detect malfunctions in the power circuits and, depending on the severity of the problem, quickly and reliably disconnect the batteries, for example, within 5ms in some cases.

[0087] The present invention provides a contactor comprising 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 a subcircuit electrically connected between the first and second power terminals and connected in series with at least three elements: a conductive portion (e.g., a busbar portion), a main switch including a movable part driven by an actuator, and a fuse (e.g., a pyrofuse or squib), all of which are embedded in the 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 conductive portion. The contactor further includes a controller (e.g., a programmable microcontroller) communicably connected to the magnetic sensor for measuring the primary current flowing through the conductive 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 the electrical characteristics of the actuator).

[0088] According to an important aspect of the present invention, the controller is further configured to (i) measure the primary current flowing through the conductive portion and to 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 (for example, after a time interval Δt at the moment the actuator was operated), blow the fuse.

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

[0090] The time interval Δt may be a predefined time interval, or it may be calculated as a function of the measured HV current (e.g., using a lookup table). This period may be determined only once after the measurement of the HV current, or it 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 therefore can also detect if the switch was not opened for any reason. This can happen, for example, if the switch contacts become 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] The advantage is that the magnetic sensor can measure the HV current in a non-contact manner. In this way, the contactor may have two voltage regions: a primary voltage region (for example, operating at 60 volts or more, for example at 120 volts or more or 200 volts or more, also referred to herein as the “high voltage region” or HV region), and a secondary voltage region (for example, operating at 48 volts or less, for example at 36 volts or less, for example at 24 volts or less, for example at 12 volts or less, also referred to herein as the “low voltage region” or LV region). The magnetic sensor may be physically located near the conductive portion (e.g., the busbar portion), which is part of the HV region but operates in the LV region and is preferably also thermally insulated from the conductive portion.

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

[0094] The advantage is that the contactor can autonomously detect whether the switch is open or closed, without relying on (or solely relying on) measurements from a magnetic sensor (which may be broken or damaged), and / or without needing to communicate with an external device (whose communication channel may be interrupted and / or cause delays), and / or without using or relying on external components of the contactor. This provides redundancy (at the system level) and therefore improves the overall safety and reliability of the power system in which this contactor is used.

[0095] The main advantage is that by inspecting the switch status itself (inside the contactor) as possible and actually, and / or by measuring the HV current itself (inside the contactor), and / or by determining the overcurrent condition itself (inside the contactor), the communication loop 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). Consequently, this shortened loop provides extra time to attempt to open the switch without having to blow a fuse that would irreversibly damage the contactor. Therefore, thanks to the diagnostic capabilities inside the contactor itself, the lifespan of the contactor can be extended by avoiding blowing a fuse, for example, in situations where the current is sufficiently small and / or there is enough time to safely open the switch.

[0096] In other words, the advantage of this contactor is that (under certain conditions) it can 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 loop or decision-making loop, the probability of needing to blow the fuse in accordance with safety standards can be reduced.

[0097] The advantage is that the “detection means” provides a means (a form of internal diagnosis) to analyze whether the switch is closed, in a manner that differs from current measurement performed by a magnetic sensor. In this way, the reliability of the contactor can be increased, and the safety of the power system in which this contactor is used can be improved. Surprisingly, the lifespan of the contactor can also be extended because, without the detection means, the only safe option would be to blow the fuse. In contrast, the contactor of the present invention can make a better judgment to determine whether the current is small enough and / or whether there is enough time to attempt to open the switch, and if this is successful, there is no need to blow the fuse.

[0098] The advantage is that the fuse is also integrated into the contactor housing, as it provides protection for the fuse and for the interconnection between the controller and the fuse. Therefore, the risk of the fuse not blowing is reduced, further enhancing the overall safety of the 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., an external ECU, e.g., an airbag ECU, and / or a battery management system controller) to transmit and receive information or commands, for example, to provide signals indicating measured current and / or commands: a command to open a switch (or disconnect the battery), a command to close a switch (or connect the battery), and a command to blow a fuse.

[0100] In such embodiments, 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 a measured current with a threshold or by using a classical I2T (ampere-squared-second) method; or B) reception of a command from an external processor, for example from an airbag controller, to disconnect the battery or open the switch.

[0101] However, other forms of communication are also possible. For example, a contactor can receive a command to unconditionally blow a fuse, or a contactor can report an abnormal HV current.

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

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

[0104] Now, refer to the diagram.

[0105] Figure 1 shows a high-level block diagram of a power circuit 100, which includes 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 electrical load 120 (e.g., an electric two-phase or electric 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), such as a car. Of course, in practice, the power circuit 100 may include further components such as an inverter (not shown).

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

[0107] The contactor 150 includes a subcircuit electrically connected between the first power terminal 151a and the second power terminal 151b, and includes at least three elements connected in series: a conductive 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 conductive portion 154 may be formed integrally with the first power terminal 151a or integrally with the second power terminal 151b, but this is not absolutely necessary.

[0108] If fuse 158 remains undamaged and switch 153 is closed, the circuit formed between the first and second terminals 151a, 151b is conductive, i.e., the battery is connected to the electrical load. If switch 153 is open and / or fuse 158 is blown, the circuit formed between the first and second terminals 151a, 151b is open, i.e., in other words, 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 RC oscillator), and the like. The controller 160 is located outside the contactor and connected to the contactor, and is powered by a low-voltage power supply, e.g., a second battery, and is configured to provide a low-voltage power supply of, 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 is powered directly by this low-voltage power supply or by a voltage derived from this low-voltage power supply, e.g., 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 such an integrated circuit is shown in Figure 5.

[0110] The contactor 150 further includes a housing (not explicitly shown, but schematically represented by a rectangle 150 with rounded corners). As illustrated, the switch 153, fuse 158, and controller 160 are located inside the housing. This reduces the risk of being unable to blow the fuse in an emergency, for example, after a collision. Importantly, the switch 153 and fuse 158 operate in the high-voltage region, while the controller 160 (and other components described further) operate in the low-voltage region, galvanically separated from the high-voltage region.

[0111] The contactor further includes a magnetic sensor 155 configured to measure (in a non-contact manner) the current flowing through the conductive portion 154. Magnetic current sensors are known in the art and therefore do not need to be described in full here. To put it bluntly, 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, but other magnetic sensor structures may also be used, such as a magnetoresistive (MR) element, or at least two Hall elements spaced apart and oriented in the same direction, which enable the determination of the magnetic field gradient. By using a difference signal or a gradient signal, it becomes possible to determine the current flowing through the conductive portion 154 with reduced influence from external disturbance fields and thus with improved accuracy. The magnetic sensor may include a magnetic flux centrifuge.

[0112] Values ​​obtained from a magnetic sensor element, or from a magnetic sensor structure including that magnetic sensor element (e.g., a Wheatstone bridge), 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 value, or a subset of the current value, may be transmitted to an external processor, such as an external ECU, via a communication bus, such as a CAN interface.

[0113] The magnetic sensor 155 may be embedded in the same silicon substrate as the controller 160, or it may be located outside the controller 160 but electrically connected to it. 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 current measurement with a higher signal-to-noise ratio (SNR).

[0114] The switch 153 includes a movable part (not shown) driven by an actuator 156. The actuator 156 may be an electromagnetic actuator including a coil ( schematically illustrated in Figure 2) and a movable 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) or normally closed (NC) state. The movable element can be controlled, for example, by sending a secondary current (LV current) through the coil (for example, as illustrated in Figure 2). Such switches 153 and actuators 156 are well known in the art and therefore do not need to 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 envisioned. In the 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 signals are analyzed by a controller 160 (e.g., in software). In the second embodiment, the actuator 156 includes a coil and magnetic positioning means, also known as a “proximity switch,” such as a linear position detector or magnetic presence detector. The proximity switch may include a transmission 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 movable 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] The main advantage of adding the detection means 157 inside the contactor 150 is that the control device 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. Since the detection means is also incorporated within the housing, the risk of malfunction caused, for example, by signal disturbances or communication link interruptions is greatly reduced.

[0117] It should be noted that the detection means 157 described herein can also be used for safety testing (at the system level) by, for example, testing whether a main switch is stuck open or stuck closed. This is possible even if two contactors according to the present 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 as well, it is possible to test 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 (e.g., OUT2 in Figure 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 explains how the contactor 150 proposed by the present invention may function.

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

[0121] An external processor 130 may request the contactor 150 to measure the (primary) current flowing through the conductive portion 154. The controller 160 will acquire a signal (e.g., a voltage signal) from the magnetic sensor 155 and convert it itself into a current signal in a manner known in the art (e.g., by amplifying, digitizing, and multiplying by a constant K). The constant K may be hardcoded 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 which may be placed near the magnetic sensor. In the integrated circuit of Figure 5, both the magnetic sensor and the temperature sensor are integrated into the integrated circuit, but the present 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, such as a CAN bus. The non-volatile memory 161 may be incorporated inside the controller 160, for example, in the form of flash memory, or it may be a separate component connected to the 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 from an external processor to do so), to detect the 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 the non-volatile memory 161), or on the classical I2T (ampere-squared time) method, or a combination of both. This will be discussed further with reference to Figure 3. As described above, if the controller detects an overcurrent condition, the controller will first attempt to open the switch, and if the switch is not opened, it will attempt to blow the fuse as described in steps (i) to (iii) above.

[0123] The external processor 130 may instruct the contactor 150 to disconnect from the HV battery (or to open switch 153). A classic contactor would simply operate actuator 156 to open switch 153 (in an open-loop manner), but it would be uncertain whether the switch would actually open. The external processor may also request a new current measurement, and if the external processor learns that the current is not dropping, it may send a new request to the contactor to open switch 153, which may fail again, until the external processor instructs another component to blow a fuse. This is not ideal and may require excessive time, potentially leading to a dangerous situation.

[0124] As another example, suppose the external processor 130 is an airbag ECU, and a collision occurs that causes the airbags to deploy. When such an event occurs, as a safety precaution, the airbag ECU may send a command to unconditionally blow the fuse.

[0125] The inventors of this invention recognized that these prior art solutions are not ideal, and that there may be situations where it is possible to open the switch instead of blowing the fuse, provided that the switch is guaranteed to be effectively open. If this is possible, the lifespan of the contactor could be extended, provided that safety is guaranteed. This is an important insight that forms the basis of this invention.

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

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

[0128] The controller 160 and / or the printed circuit board on which the controller 160 may be mounted are electrically isolated (galvanically isolated) from the HV region, particularly from the conductive portion 154 (e.g., the busbar portion), 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 subsampled version of the HV current may be provided to an external ECU, such as a battery management system controller (e.g., at a rate of 100 Hz to 500 Hz).

[0130] Figure 2 shows a block diagram of a contactor 250 and power circuit 200, which includes at least one such contactor, and can be considered a modified or specific implementation of the contactor 150 and power circuit 100 of Figure 1. Similar elements are indicated by similar 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 Figure 2 is an electromagnet containing a coil. - The detection means 257 of the contactor 250 includes a shunt resistor 264, - Detection of whether the switch is open or closed can be performed by applying a known waveform, such as a step function (i.e., a waveform that changes abruptly from logic "0" to logic "1") or a pulse-width modulation 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 (by looking at some parameters such as time constants or waveform shape). This analysis may be based on a model of an RLC circuit with a moving element. -In addition, detection of whether the switch is open or closed may also take into account a value obtained from a magnetic sensor (indicating the HV current flowing through the conductive part) if this current is not zero. -The controller 260 of the contactor 250 shown in Figure 2 has at least one, for example, two communication ports, for example, two serial communication ports. In the particular example shown in Figure 2, the first communication port is used or can be used to communicate with the general ECU or 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 incorporated into an integrated circuit or semiconductor chip, for example, a packaged semiconductor device. This chip may be configured to be powered directly or indirectly from a 5V power supply, or directly or indirectly from a 12V power supply. The magnetic sensor 255 may be at least one Hall element or at least one magnetoresistive (MR) element, or may include these, and is preferably integrated into an integrated circuit or inside the same packaged device. - The contactor 250 may further include a “fuse actuation circuit” 263, schematically illustrated herein by the switch symbol. In practice, this may be, for example, a transistor or a dedicated fuse driver chip (for example, 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 thermally isolated from the HV region.

[0132] In the modified example shown in 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 on the path from the battery to the load and another contactor on the return path from the load to the battery.

[0133] Figure 3 shows an exemplary “time-current curve” that may be used in embodiments of the present invention to determine how much time Δtav is available to attempt to open switches 153, 253, for example, as a function of the measured HV current flowing through conductive portions 154, 254. Such a graph may be specific to a particular vehicle type and may depend on the dimensions of the busbar network, the thermal limits of the powertrain module, etc. The graph may be considered given for a particular project. The values ​​of this graph may be stored in the controller’s non-volatile memory in any preferred format (e.g., as a table, or as a piecewise linear curve, or as a set of parameters in an algebraic representation, or in any other preferred format).

[0134] As described above, the controllers 160, 260 of the contactors 150, 250 can measure the HV current flowing through the conductive portions 154, 254 on demand or autonomously. Depending on the specific implementation of the switch and / or actuator and / or low-voltage power supply, it typically takes a finite time Δtreq (required time) to open the switch under normal circumstances (i.e., assuming the moving parts are not stuck), for example, about 90 ms for certain types of switches, but of course, the present invention is not limited thereto.

[0135] If the controller measures the HV current and this measured current is greater than the value Imax (see Figure 3), the controller will find that it does not have enough time to attempt to open the switch further, and therefore will immediately blow the fuse. The maximum time that the measured current is allowed to flow when it is less than Imax is shown in this graph. For example, if the measured current is equal to i1, the maximum time is t1. If the maximum allowable time is less than the time typically required to open the switch or to perform a safety test (e.g., 90ms as described above), depending on the implementation, then it is again not worth attempting to open the switch further, and the controller will immediately blow the fuse. However, if the measured HV current is equal to i2, the maximum time is t2, and if this time is longer than the time typically required for the safety test to precede and open the switch (for example, longer than the 90ms mentioned above), then it is perfectly reasonable to first attempt to open the switch in a reversible manner using the actuator, and only if it is determined that the switch cannot be opened or cannot be opened within the assumed period will the controller ultimately decide to blow the fuse. In this way, the controller of the present invention can ensure safety while maximizing the lifespan of the contactor.

[0136] Of course, the 90ms value is just one example, and other switches and actuators can be used, but the same principle applies.

[0137] Figure 4A shows a flowchart of method 400 for interrupting the current flowing through contactors 150, 250, as shown in Figure 1 or Figure 2. Method 400 includes the following steps: a) Step 401, which measures the current flowing through the conductive portions 154, 254 of the contactors 150, 250 at least once or repeatedly. b) Step 403 to detect an overcurrent condition (based on one or more measured current values), c) Step 406, open the primary switches 153, 253 and, based on the measured current values, determine the available time Δtav to perform the safety test, optionally by taking into account the time typically required to open the switches and / or to perform the safety test, for example, by taking into account a current-versus-time table or curve or mathematical formula. d) Compare the available time Δtav with the typically required time Δtreq (407), If the available time Δtav is less than the required time Δtreq, proceed to step g). Otherwise, proceed to step e), e) Step 408, operate actuators 156, 256 to open (or attempt to open) switches 153, 253. f) Using detection means 157, 257, detect whether switches 153 and 253 are effectively open within the available period Δtav. If switches 153 and 253 remain closed after the available period Δtav, proceed to step 409, g). g) Step 412: Blowing the fuse.

[0138] The advantage is that the controller performs step 403 (determining the overcurrent condition), because this automatically triggers the opening of the switch and / or the blowing of the fuse sooner (for example, 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 the fuse surviving.

[0139] Method 400 describes a relatively simple procedure and illustrates the most important step proposed by the present invention. However, many modifications of this method are possible.

[0140] In the modified version shown in Figure 4A, steps c) and d) are omitted, the branch for blowing the fuse is omitted, and the timeout value in step 410 is predefined (e.g., hardcoded). In such an embodiment, if the contactor is in step a), it 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), and then evaluate 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] Figure 4B shows a flowchart of Method 410, a further variation of the method described above, where, after detecting that an overcurrent condition has occurred (or is part of one), the contactor tests (in step 414) whether the measured primary current is greater than a predefined (critical) threshold, and if so, the contactor blows the fuse (in step g). Otherwise, the contactor first attempts to open the main switch in steps e) and f), and (in step 410) evaluates whether the main switch is actually open after a predefined timeout period ΔT. If the main switch is not open, the contactor blows the fuse (in step g).

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

[0143] The advantage of this method 410 is that the available time Δtav is updated at least once, for example dynamically, taking into account the most recent measurement of the primary current (in step a), and thus effectively taking into account the fluctuations in the primary current during the time it is attempting to open the switch.

[0144] Figure 4D shows a flowchart of method 430 for interrupting the current flowing through contactors 150, 250, which can be considered another modification of method 400 in Figure 4A. The most important difference between method 430 in Figure 4D and method 400 in Figure 4A is, An attempt 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 disconnect the battery, etc.) coming from a controller, processor, or ECU located outside the contactor, and The contactor controller may also blow the fuse after receiving a command to blow the fuse unconditionally from a controller, processor, or ECU located outside the contactor.

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

[0146] Figures 4A to 4D show four examples of methods that can be implemented by the contactor controller proposed herein, but of course, other modifications are possible in practice.

[0147] As described above, testing, evaluating, or assessing whether the main switches 153, 253 are actually open 409 can be done indirectly by evaluating the state of the actuator. The state of the actuator can be determined, for example, by measuring and analyzing the current waveform of the actuator (e.g., using a shunt resistor) to detect whether the movable 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 by any other suitable method.

[0148] Step 409, which detects whether the switch is open, may also include measuring a voltage across the shunt resistor and / or across the coil (or a coil in series with the switch, or a coil in series with the shunt), and therefore may involve multiple voltage measurements. These two voltages may be measured and sampled using a time-multiplexing scheme and one or two analog-to-digital converters (ADCs).

[0149] Of course, the controllers 160 and 260 for contactors 150 and 250 are also, for example, -Other tasks (not shown in Figures 4A to 4D) may be performed, such as periodically transmitting the measured current value to an external processor, for example, a battery junction box (BJB) or battery disconnection unit (BDU), which may also be called a power relay assembly (PRA). As mentioned above, the rate at which the current value is transmitted may be lower than the rate at which the primary current is measured and may be used internally to evaluate overcurrent conditions.

[0150] Figure 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 in Figure 5 includes the following: - A controller in the form of a programmable processor, such as a programmable microcontroller or digital signal processor (DSP), - A magnetic sensor, for example, a circuit including one or more horizontal Hall elements, one or more vertical Hall elements, a magnetoresistive (MR) element, optionally an integrated flux centrifuge (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. -(For example, as shown in Figure 2) A voltage sensing interface for sensing voltage across a coil, which can be connected to an integrated circuit. -Optionally, a first output OUT1 for driving actuators 156 and 256 using a PWM signal. - A second output OUT2 to activate or trigger a fuse driver, such as a pyro fuse driver. -Executable instructions for a controller, i) Using the magnetic sensor, measure the primary current 401 to detect whether an overcurrent condition has occurred 403, and if an overcurrent condition is detected, proceed to step ii), otherwise repeat step i), ii) Assert the first output OUT1 in order to operate the actuator and open the 408 main switches 153 and 253. iii) A non-volatile memory containing instructions to detect whether the main switches 153, 253 are effectively open by analyzing signals obtained from the shunt interface and signals obtained from the voltage sensing interface, 409 and if it is detected that the main switches are still closed after a certain time interval (e.g., Δtav), to assert a second output OUT2 to blow the fuses 158, 258, 412.

[0152] Non-volatile memory may also include data corresponding to current-vs-time curves.

[0153] The "shunt interface," "voltage sensing interface," and "power supply voltage interface" are indicated by six terminals (or pins), but they are not absolutely necessary, as some signals can 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 the following: a clock generator (e.g., based on a crystal or RC oscillator), a voltage regulator, a timer unit, an analog multiplexer, a pulse-width modulation (PWM) generator block connectable to a first output OUT1, for example, a digital communication interface for receiving instructions from an external processor, an analog-to-digital converter (ADC) configured to digitize signals acquired from a shunt interface and from a voltage sensing interface, a 12-volt power input, a timer unit, an NTC interface (negative temperature coefficient component) for measuring external temperature, and a temperature sensor for measuring or estimating the temperature of a magnetic sensor.

[0155] Figure 6 shows a block diagram of an integrated circuit 600, which can be seen as a modification of the integrated circuit 500 of Figure 5, having a coil interface circuit including an integrated shunt resistor and a coil interface circuit comprising an integrated transistor for controlling the flow of current through the coil.

Claims

1. A contactor (150, 250), 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 actuated by an actuator (156, 256); a magnetic sensor (155, 255) configured to measure a primary current flowing through the conductor 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); said contactor (150, 250) further comprising detection means (157, 257) for detecting whether said main switch (153, 253) is actually open or closed, The controller (160, 260), i) measuring 401 the primary current to detect 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 master 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 the main switch is detected to still be 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) a time period (Δtav) available to open the main switch (153, 253); d) comparing (407) the available time period (Δtav) with the time period (Δtreq) required to open the main switch (153, 253), and if the available time period is less than the required time period, continuing with step g), otherwise continuing with step e); e) operating (408) the actuator (156, 256) to open the master switch (153, 253); f) detecting (409) whether the main switch (153, 253) is effectively open and blowing (412) the fuse if the main switch (153, 253) is still closed after the available time period (Δtav).

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 amps 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 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 moveable element moveable 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 a 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. said detection means (157, 257) comprising a position sensor for detecting the position of said movable element; The contactor (150, 250) of any one of claims 1 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 arranged 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 magnetoresistance 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, oriented parallel and configured to measure a magnetic field differential or a magnetic field gradient.

11. further comprising an accelerometer and / or a 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 detection 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 operating 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 a signal obtained from the shunt interface, and to assert (412) the second output (Output 2) to blow (158, 258) the fuse 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).

Images