Circuit protection scheme for power systems

Abstract

To provide a cable system that incorporates a circuit breaker component or device that can be triggered in the event of a detected fault, in order to prevent damage to the electrical system, electrical components, or cable system. [Solution] A circuit 200 for controlling circuit faults comprises a battery, a disconnecting contactor circuit electrically connected to the battery, and a system controller, wherein the disconnecting contactor circuit electrically connects the battery to the end of the load when closed and electrically isolates the battery from the end of the load when open. The system controller detects a fault in the circuit including the battery and the disconnecting contactor circuit while the disconnecting contactor is in the closed state, and in response to the detection of the fault, further switches the disconnecting contactor to open.

Description

Technical Field

[0001] The present disclosure relates to power systems. More particularly, the disclosed technology relates to circuit protection for power distribution in electric vehicles.

Background Art

[0002] Electric vehicles and related infrastructure can utilize a conductive cable system for supplying electricity. These cable systems can provide a high current capacity at voltages for electric vehicles and charging systems. These cables are typically flexible and include a conductive metal encapsulated by one or more layers of insulators and metal sleeves for touch safety and electromagnetic compatibility (EMC) shielding.

[0003] In some scenarios, the cable system or electrical system may experience problems related to unwanted or fault currents experienced in the cable system. For example, a failure of one or more components such as a motor controller can generate unwanted or fault currents. In some other examples, deformation of components caused by a vehicle collision can cause sudden and / or dangerous fault currents. In yet other examples, a failure of a charging component or system can also result in unwanted currents.

[0004] To prevent damage to an electrical system, electrical components, or cable system, the cable system can incorporate a circuit breaker component or device that can be triggered in the event of a detected fault.

Summary of the Invention

[0005] Each of the systems, methods, and devices disclosed herein has several innovative embodiments, and not just one of them alone is responsible for all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described herein are given in the accompanying drawings and the following description.

[0006] In some embodiments, the technology described herein relates to a system with circuit fault protection, the system comprising: a battery; a disconnecting contactor electrically connected to the battery, configured to electrically connect the battery to the end of a load in a closed state and to electrically isolate the battery from the end of a load in an open state; and a controller configured to detect a fault in a circuit including the battery and the disconnecting contactor while the disconnecting contactor is in a closed state, and to switch the disconnecting contactor to an open state in response to the detection of a fault.

[0007] In some embodiments, the technology described herein relates to a system in which the controller is configured to switch the blocking contactor to an open state in less than 1 millisecond after detecting a fault.

[0008] In some embodiments, the technology described herein relates to a system in which, in order to switch a blocking contactor to an open state, the controller is configured to reduce the coil current of the blocking contactor by switching the state of at least a transistor, and when the coil current of the blocking contactor is reduced, the blocking contactor enters an open state.

[0009] In some embodiments, the technology described herein relates to a system in which, in order to reduce the coil current of a cutoff contactor, the controller is configured to switch the state of a second transistor, the second transistor applying a pulse-width modulated signal to the circuit during normal operation, and the second transistor is connected to ground.

[0010] In some embodiments, the technology described herein relates to a system in which a bus voltage is applied to a cutoff contactor by switching the state of a transistor, and after the application of the bus voltage, the arc voltage of the cutoff contactor is greater than the battery supply voltage.

[0011] In some embodiments, the technology described herein relates to a system in which a diode in parallel with a transistor is configured to function as a voltage source for a voltage applied to a cutoff contactor, and the bus applied to the cutoff contactor coil rapidly reduces the coil current.

[0012] In some embodiments, the technology described herein relates to a system, the system further including a second disconnection contactor that is electrically in communication with a battery.

[0013] In some embodiments, the technology described herein relates to a system, the controller further configured to restore the system to operation after the fault has been resolved.

[0014] In some embodiments, the technology described herein relates to a system configured to provide circuit fault protection while the controller is not powered.

[0015] In some embodiments, the technology described herein relates to a system in which the circuit is fuse-less.

[0016] In some embodiments, the technology described herein relates to a system for controlling a circuit fault, the system comprising: a battery; a plurality of interrupting contactors, including a first interrupting contactor configured to electrically connect the battery to a first end of a load in a closed state and to electrically isolate the battery from the first end of the load in an open state; and a second interrupting contactor configured to electrically connect the battery to a second end of a load in a closed state and to electrically isolate the battery from the load in an open state; and a control circuit configured to detect a fault while the first interrupting contactor is in a closed state and to switch the first interrupting contactor to an open state in response to the detection of a fault.

[0017] In some embodiments, the technology described herein relates to a system, the control circuit further comprising: a first transistor electrically communicating with a first blocking contactor; a first diode in parallel with the first field-effect transistor; a second transistor connected between the first blocking contactor and ground; a third transistor electrically communicating with a second blocking contactor; a third diode in parallel with the third transistor; and a fourth transistor connected between the second blocking contactor and ground.

[0018] In some embodiments, the technology described herein relates to a system, the system further comprising a third interrupting contactor in series with a first interrupting contactor.

[0019] In some embodiments, the technology described herein relates to a system in which the control circuit is configured to switch the blocking contactor to an open state in less than 1 millisecond after detecting a fault.

[0020] In some embodiments, the technology described herein relates to a method for protecting a circuit, the method comprising: detecting a fault condition in a circuit including a disconnecting contactor and a battery, wherein the disconnecting contactor is closed to electrically connect the battery terminals to a load during detection, and the fault condition is related to a fault current applied to the circuit; and in response to the detection, opening the disconnecting contactor to electrically isolate the battery terminals from the load, thereby interrupting the fault current.

[0021] In some embodiments, the techniques described herein relate to a method in which the step of transitioning the interrupting contactor to an open state is performed in less than 1 millisecond after detecting a fault condition.

[0022] In some embodiments, the techniques described herein relate to methods, wherein the step of opening a disconnecting contactor further includes the step of applying a bus voltage greater than the battery supply voltage to the disconnecting contactor.

[0023] In some embodiments, the techniques described herein relate to a method wherein the step of applying a voltage greater than the battery supply voltage further includes the step of switching the state of a transistor, by which a diode in parallel with the transistor acts as a voltage source for the voltage applied to the interrupting contactor coil, and the voltage applied to the interrupting contactor causes the coil current of the interrupting contactor to decrease rapidly.

[0024] In some embodiments, the technique described herein relates to a method wherein the step of applying a voltage greater than the battery overstress voltage further includes the step of switching the state of a second transistor, the second transistor applying a pulse-width modulated signal to the circuit, and the second transistor being connected to ground.

[0025] In some embodiments, the techniques described herein relate to methods, where the failure condition is a short circuit. [Brief explanation of the drawing]

[0026] Aspects and advantages of the technology disclosed herein are described herein with reference to the drawings of the preferred embodiments and are intended to illustrate the present invention and not to limit it.

[0027] [Figure 1] A schematic diagram of an exemplary electric vehicle according to some aspects of the present disclosure is shown.

[0028] [Figure 2] FIG. is an exemplary schematic diagram of a circuit for battery protection using a cutoff contact according to some aspects of the present disclosure.

[0029] <​​​​​​​​​​​​​​​​​​​​​​​​​​​Generally speaking, aspects of this disclosure relate to circuit protection schemes for power systems. Power systems may include, but are not limited to, batteries, supercapacitors, alternating current (AC) grid systems, or any combination thereof. Exemplarily, a circuit may include one or more interrupting contactors electrically connected to a battery or battery pack. A system controller may monitor the circuit to detect one or more faults. If a fault is detected, the controller may open the interrupting contactors. The system controller may implement a fast coil turn-off method to rapidly reduce the coil current of the inductor of the interrupting contactor. The reduction in coil current may allow the interrupting contactor to open more quickly. By opening the contactor more quickly, damage to the circuit can be prevented or reduced. By opening the contactor more quickly, damage to the surrounding environment can be prevented. The interrupting contactor may be implemented, for example, in an electric vehicle. By opening the contactor, damage and / or injury to repair personnel and equipment around the electric vehicle can be prevented. The circuit protection scheme may be a fuseless scheme configured to rapidly mitigate high currents in a short time. For example, the circuit protection scheme may be configured to handle a current of 10,000 amperes (A) within 1 millisecond (ms).

[0034] In some embodiments, such as those relating to electric vehicles and electric vehicle charging systems, the electrical system may be subjected to voltages ranging from 450 volts (V) to 1000 V, or possibly higher. Such voltages are generally considered “high voltage” applications and can achieve the power demands associated with relatively fast electric vehicle charging. In the event of a fault or other detected event, the vehicle and / or charging cable system may incorporate one or more circuit breaker components that can be triggered to avoid damage to the vehicle, external charging system, user, or any appropriate combination thereof. Certain circuit breaker components may include fuse-based components or circuit breaker-based components.

[0035] Circuit breakers can generally operate by creating an open circuit between two points in a cable system to interrupt the flow of current between those two points. One way of handling circuit interruption is to use a thermal fuse to interrupt faults such as short circuits. A thermal fuse may be established between a battery and one or more contactors. Thermal fuses may be slower to interrupt moderate currents. This slow interruption can damage the contactors. This can reduce the reliability of the contactors. In this method, the controller continues to supply power to the contactors during the fault event, keeping them closed and activating the fuse. In some cases, this can cause the contactors to rupture, increasing the risk of circuit damage. Furthermore, thermal fuses may take time to melt and interrupt the short circuit, which can increase the risk of circuit damage.

[0036] Another typical example of a method for handling circuit interruption is the use of a pyro-fusel. The use of a pyro-fusel can reduce the risk of contactor rupture by at least reducing the amount of current flowing through the contactor. However, pyro-fusels are typically replaced after each use. Furthermore, pyro-fusels are active devices. The controller is powered to constantly monitor the circuit containing the pyro-fusel for short-circuit events. In automotive environments such as electric vehicles, the system controller may have reliability issues. Since the system controller must always be on to enable the pyro-fusel in the fault protection circuit, reliability issues in the system controller can lead to reliability issues in the fault protection circuit.

[0037] In particular, the above-mentioned problems are addressed by embodiments of the present disclosure, which address these technical problems by using a system controller to rapidly reduce the coil current of the interrupting contactor for a fault protection circuit including an interrupting contactor and a battery. The fault protection circuit may be fuse-less. In other words, the fault protection circuit may not include a fuse (e.g., a thermal fuse, a pyrotechnic fuse, etc.). Instead, the system controller can switch the state of the interrupting contactor to open and close the fault protection circuit. Circuit protection can be provided when the system controller is not powered (e.g., when an electric vehicle is stopped).

[0038] The controller may be electrically connected to the interruption contactor, for example, via a control circuit. The system controller, interruption contactor, and control circuit (for brevity, the “interruption contactor circuit”) may be part of a larger fault protection circuit that includes a battery and load. The load may be, for example, a motor. The motor may be part of an electric vehicle (EV).

[0039] Under normal operation, the blocking contactor may be in a closed state. In some examples, a pulse-width modulation (PWM) control signal may be received by the blocking contactor circuit. A system controller may provide, for example, a PWM control signal. In some examples, the PWM control signal may change the voltage to maintain the coil current at a level that keeps the blocking contactor closed. In further examples, the inductance caused by the blocking contactor may maintain the coil current flowing through the blocking contactor as the PWM control signal changes the voltage. The system controller may be electrically connected to the blocking contactor circuit. When a fault is detected in the fault protection circuit, the system controller may remove power from the blocking contactor circuit to result in a rapid reduction of the coil current (also referred to herein as "ultrafast coil turn-off"). Ultrafast coil turn-off can reduce the coil current in the circuit in, for example, less than 1 millisecond.

[0040] In some examples, a tripping contactor circuit may include a transistor. The transistor may be, for example, a field-effect transistor (FET). By turning on the FET, the inductance from the tripping contactor's solenoid can maintain the coil current flowing through the circuit when the voltage changes based on the PWM signal. To cause ultrafast coil turn-off, the system controller can change the state of the FET. Changing the state of the FET may result in a voltage being applied to the tripping contactor. Applying this voltage can reduce the coil current. Reducing the coil current allows the tripping contactor to open in a shorter time. This reduction in time can reduce the amount of damage caused by the fault current. For example, reducing the coil turn-off time can limit the duration of the arc in the tripping contactor circuit, thereby reducing the risk of the tripping contactor rupturing. As another example, reducing the coil turn-off time can quickly terminate a fault current event, thereby reducing damage to components. Quickly terminating a fault current event provides further protection to the surrounding environment of the system including the tripping circuit. In some examples, the surrounding environment may include the user who caused the fault.

[0041] In some examples, a fault protection circuit may include multiple interrupting contactors. For example, a first interrupting contactor may be electrically connected to the positive terminal of the battery. In further examples, a second interrupting contactor may be connected to the negative terminal of the battery. Alternatively, both the first and second interrupting contactors may be connected to the same terminal of the battery. Including multiple interrupting contactors can increase the reliability of the circuit. For example, if one of the interrupting contactors fails, the system controller can open one or more other interrupting contactors in the circuit. By opening other contactors, damage can be reduced as described above.

[0042] Herein, the aforementioned aspects and other aspects of the Disclosure will be described in relation to specific examples, embodiments, and aspects intended to illustrate, but not limit, the Disclosure. Many of the aforementioned aspects of the Disclosure and the associated advantages will be more readily understood by referring to the following description in conjunction with the accompanying drawings.

[0043] In this description, similar reference numbers and / or terms refer to drawings in which identical or functionally similar elements may be indicated. It will be understood that the elements shown in the drawings are not necessarily drawn to scale. Furthermore, it will be understood that certain embodiments may include more elements and / or subsets of elements shown in the drawings than those shown. In addition, some embodiments may incorporate any suitable combination of features from two or more drawings. Headings are provided for convenience only and do not affect the scope or meaning of the claims.

[0044] [Example electric vehicle] In certain applications, the circuit protections disclosed herein can be implemented in electric vehicles. Figure 1 shows a schematic diagram of an exemplary electric vehicle 100 according to several aspects of this disclosure. As shown in Figure 1, the motor 104, inverter 102, system controller 106, interruption contactor circuit 108, and battery 110 may be communicatively coupled and may form at least part of the drivetrain or powertrain of the electric vehicle 100.

[0045] The electric vehicle 100 includes at least an inverter 102, a motor 104, a system controller 106, a disconnection contactor circuit 108, and a battery 110. The inverter 102 may convert direct current (DC) to alternating current (AC). For example, the inverter 102 may convert DC to a three-phase AC current and supply it to the motor 104. The inverter 102 may utilize one or more types of power switches (e.g., Si-based, SiC-based, SiGe-based, GaN-based, GaAs-based, etc.) to supply current to the motor 104. The inverter 102 may use one or more of the following to supply current to the motor 104: field-effect transistors (FETs) such as metal oxide semiconductor FETs, junction field-effect transistors (JFETs), insulated-gate field-effect transistors (IGFETs), bipolar transistors, insulated-gate bipolar transistors (IGBTs), integrated-gate commutation thyristors (IGCTs), high electron mobility transistors (HEMTs), etc.

[0046] Motor 104 may be any suitable type of electric motor, such as an AC or DC permanent magnet motor, an AC induction motor, or an AC brushless motor. In some embodiments, motor 104 may be a three-phase AC permanent magnet motor. Motor 104 may generate driving force or torque for the electric vehicle 100 based on power supplied from the battery 110 via the inverter 102.

[0047] The battery 110 may include one or more battery packs, and each battery pack may include multiple battery cells. The configuration of the battery 110 can be determined based on a specific application. The battery 110 can supply power to the inverter 102, and the inverter 102 supplies power to the motor 104.

[0048] The system controller 106 can monitor fault protection circuits. These fault protection circuits may include, for example, one or more measurement points. One measurement point may, for example, allow for the measurement of current in the circuit. Another measurement point may, for example, allow for the measurement of voltage in the circuit. The system controller 106 can detect circuit faults based on the measurements at one or more measurement points. For example, if a circuit fault is detected, the system controller 106 can isolate the battery 110. The system controller 106 can isolate the battery 110 using, for example, a disconnection contactor circuit 108.

[0049] The interruption contactor circuit 108 may, in some examples, include an interruption contactor and a control circuit. The interruption contactor circuit 108 may be electrically connected to the battery 110. The interruption contactor circuit 110 may be configured, for example, to electrically connect the battery 110 to the load end in the closed state and to electrically isolate the battery from the load end in the open state. The interruption contactor circuit 108 can be switched between, for example, an open state and a closed state. The system controller 106 may, for example, open the interruption contactor circuit 108. Alternatively, the system controller 106 may close the interruption contactor circuit 108.

[0050] When the interrupting contactor circuit 108 is open, the fault protection circuit may also be open. This allows the battery 110 to be isolated from damage caused by overstress current, overstress voltage, or any combination thereof. In some examples, the system controller 106 may open the interrupting contactor circuit 108 using an ultrafast coil turn-off, as will be further described herein. Exemplary fault protection circuits including the system controller 106 and one or more interrupting contactor circuits 108 are further described with reference to at least Figures 2 and 3. The operation of the interrupting contactor circuit 108 is further described with reference to at least Figure 4.

[0051] [Example circuit for battery protection] Figure 2 shows an exemplary schematic diagram of a circuit 200 for facilitating battery protection using a disconnecting contactor 108, according to some aspects of the present disclosure. The battery 110 can be electrically connected to the inverter 102 and motor 104 via the disconnecting contactor circuit 108. The system controller 106 can monitor the current in the circuit 200 at the current measurement point 204. Any suitable current sensor can be implemented to measure the current. Based on the measured current indicating a fault, the system controller 108 may open at least one of the disconnecting contactor circuits 108.

[0052] In some examples, the interruption contactor circuit 108 can form part of the system controller 106. The system controller 106 may be electrically connected to the interruption contactor circuit 108. The system controller 106 can further switch the interruption contactor circuit 108 open or closed. The system controller 106 may further provide, for example, a control signal for switching the interruption contactor circuit 108 open or closed. By opening the interruption contactor circuit 108, the end of the battery 110 can be electrically isolated from the inverter 102. This could prevent the flow of current through the interruption contactor circuit 108. Therefore, by opening the interruption contactor circuit 108, damage and / or other undesirable effects on components of the circuit 200 can be prevented. By opening the interruption contactor circuit 108, for example, damage and / or other undesirable effects on the battery 110, inverter 102, and / or motor 104 can be prevented. The circuit 200 can provide fault protection when the system controller 106 is not powered. The interrupting contactor circuit 108 can be open, for example, when power is not supplied to the system controller 106 to provide fault protection. The interrupting contactor circuit 108 can also transition to an open state if the system controller 106 loses power during normal operation. This can advantageously provide passive protection for the circuit including the interrupting contactor circuit 108, the surrounding environment of such a system, or any combination thereof.

[0053] As illustrated with reference to Figure 1, the battery 110 may include one or more battery packs, and each battery pack may include multiple battery cells. As shown in Figure 2, the interruption contactor circuit 108A is connected to the positive terminal of the battery 110. The interruption contactor circuit 108B is connected to the negative terminal of the battery 110. However, other options are also possible. In some examples, both the interruption contactor circuit 108A and the interruption contactor circuit 108B may be connected to the same terminal of the battery 110. Both the interruption contactor circuit 108A and the interruption contactor circuit 108B may be connected to the positive terminal of the battery 110, for example.

[0054] As an alternative example, more or fewer interruption contactor circuits 108 may be used. For example, one interruption contactor circuit 108 may be controlled by a system controller 110 to facilitate fault protection. As an alternative example, the system controller 110 may control three or more interruption contactor circuits 108 to facilitate fault protection. Another circuit involving the use of interruption contactor circuits 108 to facilitate fault protection will be described with reference to Figure 3. Systems and methods for fast coil turn-off of the interruption contactor 108 will be described further with reference to Figures 5-6.

[0055] By utilizing multiple interruption contactor circuits 108, the reliability of the circuit can be advantageously improved. Ultra-fast coil turn-off switches the interruption contactor circuit 108 to an open state. In the open state, current may not flow through the interruption contactor circuit 108 to other components of the circuit 200. For example, the interruption contactor circuit 108 may close in response to a higher current during startup. Subsequently, the interruption contactor circuit 108 may remain closed under lower coil currents. Lower currents are sometimes referred to herein as "economy currents." The system controller 106 may, for example, turn on the interruption contactor circuit 108 at a higher current and then reduce the current to conserve the interruption contactor circuit 108.

[0056] Circuit faults can occur immediately after startup and before the interruption contactor circuit 108 is saved. This can lead to a large coil current flowing through the interruption contactor circuit 108. If multiple interruption contactor circuits 108 are present, the system controller 106 can sequentially control the turning on of the contactors. For example, interruption contactor 108A can be turned on before interruption contactor 108B. This can increase the likelihood that ultrafast coil turn-off can be applied to at least interruption contactor 108B. This reduces the risk of damage to other components of the circuit 200 if a circuit fault occurs immediately after startup.

[0057] In a further example, the interruption contactor circuit 108 may have a defect. For example, the interruption contactor of the interruption contactor circuit 108 may contain hydrogen. The defect may be the loss of some or all of the hydrogen.

[0058] This defect may, for example, prevent the interrupting contactor circuit 108A from responding to a control signal. Alternatively, the defect may delay the opening of the interrupting contactor circuit 108A, prevent its opening, or any suitable combination thereof. However, the interrupting contactor circuit 108B may not share this defect. Therefore, the interrupting contactor circuit 108B may open (also referred to herein as "entering the open state") in response to a control signal. Opening the interrupting contactor circuit 108B can favorably reduce damage to the circuit 200 by reducing the amount of current flowing through at least the components of the circuit 200.

[0059] In some examples, the system controller 106 can use the interruption contactor circuit 108 to detect or diagnose problems during startup. For example, the system controller 106 can determine whether the interruption contactor of the interruption contactor circuit 108 has lost hydrogen. In another example, the system controller 106 can detect damage to elements such as the diode 410 that interrupts the interruption contactor circuit 108. If a problem is detected, the system controller 106 can abort the startup process. However, defects may occur after the diagnostic process. As mentioned above, reliability can be improved by including multiple interruption contactor circuits 108. This is because the likelihood of defects occurring in at least all of the multiple interruption contactor circuits 108 is reduced. In some examples, the system controller 106 may be configured to return the circuit to operation after the fault has been resolved.

[0060] Figure 3 shows an exemplary schematic diagram of a circuit 300 for facilitating battery protection using a disconnecting contactor circuit 108, according to several aspects of the present disclosure. The battery 110 can be electrically connected to the inverter 102 and motor 104 via the disconnecting contactor circuit 108. The system controller 106 can monitor the current in the circuit 200 at current measurement point 204. The system controller 106 can monitor the current in the circuit 200 at any other suitable current measurement point. In certain applications, the system controller 106 can monitor the current in the circuit 200 at multiple suitable current measurement points. Based on the measured current, the system controller 108 may open at least one of the disconnecting contactor circuits 108.

[0061] As shown in Figure 3, battery 110A is electrically connected to inverter 102 via interruption contactor circuit 108C. Battery 110A is connected to battery 110B via interruption contactor circuit 108D. Battery 110B is connected via interruption contactor circuit 108E. As explained with reference to Figure 2, the reliability of circuit 300 can be advantageously improved by utilizing multiple interruption contactor circuits 108.

[0062] [Example of a disconnecting contactor circuit] Figure 4 shows an exemplary interruption contactor circuit 108, including an interruption contactor 400 and associated control circuits, according to several aspects of the present disclosure. The interruption contactor circuit 108 includes an interruption contactor 400, a power supply (PS+) 402, a flywheel-activating field-effect transistor (FET) 408, a diode 410, an FET 414, and a diode 420. A system controller (e.g., system controller 106 in Figures 2-3) can use the interruption contactor circuit 108 to perform ultrafast coil turn-off, for example, as described herein.

[0063] As shown in Figure 4, the interruption contactor 400 includes circuit elements that model the operation of the interruption contactor 400. The circuit elements include an inductor representing the solenoid 416 and a DC resistor 418 representing the DC resistance of the interruption contactor 400. The interruption contactor 400 will be further described with reference to Figure 5.

[0064] In some examples, the power supply (PS+) 402 may be connected to a larger fault protection circuit (e.g., circuit 200, circuit 300, etc.). PS+ 402 can, for example, represent a positive voltage supplied to a larger fault protection circuit.

[0065] The system controller 106 may be electrically connected to the disconnection contactor 108, as described with reference to Figures 2 and 3. The system controller 106 can, for example, control the flywheel enabler FETs 408 and 414. As further described herein, turning off the flywheel enabler FETs 408 and 414 may initiate an ultrafast coil turn-off.

[0066] The flywheel-activating FETs 408 and 414 can be p-channel metal-oxide-semiconductor FETs (P-MOSFETs), as shown in Figure 4. However, different types of transistors may be used. These different types of transistors may include, but are not limited to, n-channel metal-oxide-semiconductor FETs (N-MOSFETs), bipolar junction transistors (BJTs), insulated-gate bipolar transistors (IGBTs), or any suitable combination thereof.

[0067] In some examples, the system controller 106 can control the flywheel-activating FET 408 using a gate drive circuit. The system controller 106 can also control the FET 414 using a gate drive circuit. The system controller 106 may include, for example, one or more gate drive circuits. The system controller 106 uses one or more gate drive circuits to supply sufficient current to each of the flywheel-activating FETs 408 and 414 as both source and sink operations, thereby enabling rapid switching of the flywheel-activating FETs 408 and 414.

[0068] Diode 410 may be a transient voltage suppressor diode. Diode 410 can, for example, clamp the voltage when a transient event occurs. Diode 410 can clamp the voltage when the voltage V_TVS across diode 410 meets a threshold (e.g., exceeds ). Diode 410 may be unidirectional in some examples. Alternatively, diode 410 may be bidirectional, for example, as shown. Diode 410 may be connected in parallel with the flywheel enabler FET 408 in some examples, as shown.

[0069] Diode 420 may be a diode that allows current to flow from the power supply (PS+) 402 through the contactor 400. Diode 420 can, for example, allow coil current from the interrupting contactor 400 to flow through the interrupting contactor circuit 108, as will be further described herein.

[0070] Under normal operation, the flywheel enabler FET 408 is on and can supply current. The operation of FET 414 can, in a further example, control the cutoff contactor circuit 108. The system controller 106 can supply a PWM control signal to FET 414 to generate a coil current to close the cutoff contactor 400, for example.

[0071] When the PWM signal is on, for example, the system controller 106 can provide an on signal by a PWM control signal (CTR-PWM) 412 (for simplicity, let's call it the PWM on signal). The PWM on signal can make the voltage between the power supply (PS+) 402 and the cutoff contactor 400 substantially the same as the voltage of the power supply (PS+) 402. In some examples, the voltage between the power supply (PS+) 402 and the cutoff contactor 400 can be measured at voltage nodes CTR-A404 and CTR-B406.

[0072] In a further example, the system controller 106 may provide an off signal via a PWM control signal 412 (for simplicity, let's call it a PWM off signal). The PWM off signal can make the voltage between the cutoff contactor 400 and the FET 414 substantially 0V. The voltage V_TVS across the diode 410 may be substantially 0V. The fact that the voltage between the cutoff contactor 400 and the FET 414 is substantially 0V can be measured at voltage nodes CTR-A404 and CTR-B406 in some examples.

[0073] The PWM off signal can make the voltage between the power supply (PS+) 402 and the cutoff contactor 400 substantially the same as the voltage of the power supply (PS+) 402. The PWM on signal can make the voltage between the cutoff contactor 400 and the FET 414 substantially the same as the voltage of the power supply (PS+) 402. The voltage V_TVS across the diode 410 can be substantially 0V.

[0074] FET414 can further provide a path to ground for the interrupting contactor 400. The system controller 106 can supply current to the solenoid of the interrupting contactor 400, for example, as further described with reference to Figure 5. In some examples, the system controller 106 can cause the interrupting contactor 400 to close with a larger coil current at startup. In further examples, the system controller 106 can cause the interrupting contactor 400 to remain closed thereafter with an economy current. Generating an economy current can facilitate ultrafast coil turn-off. By reducing the coil current to an economy current, the coil current can be dissipated more quickly when ultrafast coil turn-off is initiated, for example, as described herein. The time required to perform ultrafast coil turn-off with an economy current may be less than 1 millisecond in some examples.

[0075] An economy current can be, for example, half an ampere ("0.5A"). A larger coil current can be, for example, about 3 amperes. The time required to perform an ultrafast coil turn-off with an economy current can be about half a millisecond ("0.5ms") in some examples. An ultrafast coil turn-off can be performed in less than 1ms.

[0076] FET414 can be turned on when a PWM ON signal is supplied by the system controller 106. When FET414 is on, current flows from PS+402 through solenoid 416, FET414, and to ground. However, when FET414 is turned off, solenoid 416 can recirculate the coil current through the cutoff contactor 400 and diode 410. FET414 may also be off when a PWM OFF signal is supplied by the system controller 106. The inductance of solenoid 416 can keep the coil current nearly constant when the PWM signal switches FET414 on and off. By switching FET414 on and off, the voltage supplied to the cutoff contactor circuit 108 can be switched on and off.

[0077] To open the cutoff contactor 400, the system controller 106 can shut off the PWM signal to the FET 414. When the PWM signal is shut off, the FET 414 may remain off. However, the recirculating coil current based on the inductance of the solenoid 416 may have to dissipate substantially before the cutoff contactor 400 can be opened. The time it takes for the coil current to dissipate may depend on one or more of several factors. These factors may include, but are not limited to, the inductance of the solenoid 416, the resistance of the cutoff contactor circuit 108, and the coil current that was flowing through the cutoff contactor circuit 108 when the system controller 106 shut off the PWM signal to the FET 414.

[0078] While the coil current dissipates, the interrupting contactor 400 can open relatively slowly. Components that keep the interrupting contactor 400 closed may gradually separate and generate an arc, as further explained with reference to Figure 5, for example. The arc can be caused by the fault current. The longer it takes for the current to dissipate, the longer the interrupting contactor 400 may remain closed. Longer times can also result in a larger arc being generated within the interrupting contactor 400. A larger arc can correspond to a higher arc voltage. This can cause the interrupting contactor 400 to rupture. To speed up the process of opening the interrupting contactor 400, the system controller 106 can perform an ultrafast coil turn-off. This can reduce the time it takes to open the contactor. This can also reduce the time it takes for an arc to be generated within the interrupting contactor 400. The reduction in time can reduce the size of the arc. A smaller arc can correspond to a smaller arc voltage. The interrupting contactor 400 may be less likely to rupture due to the reduced arc size.

[0079] To perform ultra-fast coil turn-off, the system controller 106 can turn off FET 414. Furthermore, the system controller 106 can insert a high series voltage into the interruption contactor circuit 108. The system controller 106 can, for example, turn off the flywheel enabler FET 408. By switching off the flywheel enabler FET 408, the diode 410 can function as a voltage source for the bus voltage. The bus voltage may be greater than the arc voltage of the interruption contactor 400. After the bus voltage is applied, the arc voltage of the interruption contactor 400 may be greater than the battery supply voltage. The voltage V_TVS across diode 410 may be on the scale of tens of volts (V) in some examples. The voltage V_TVS across diode 410 may be, for example, about 100V. When the flywheel enabler FET 408 is switched off, the flywheel enabler FET 408 may also be turned off.

[0080] In some examples, the flywheel enabler FETs 408 and 414 may be off when the system controller is off. Therefore, the system controller 106 does not need to be on to perform the ultrafast coil turn-off. If the system controller 106 fails, for example, the current to the flywheel enabler FETs 408 and 414 will stop. Then the ultrafast coil turn-off will proceed as described above. Therefore, the system may be configured to provide circuit fault protection while the controller is not powered.

[0081] [Example operation of a disconnecting contactor] Figure 5 shows exemplary operation of the interruption contactor 400 according to several embodiments of the present disclosure. As described herein, the interruption contactor 400 may be a hydrogen refueling switch capable of switching a DC electrical load. The interruption contactor 400 may be part of an interruption contactor circuit 108, as described herein, for example, with reference to Figures 1 to 4. Components of the interruption contactor 400 can facilitate the direction of arcs generated within the interruption contactor 400. Arcs may be generated within the interruption contactor 400, for example, as a result of a fault current. The fault current may be, for example, a short-circuit current.

[0082] The interruption contactor 400 is shown in Figure 4 as a hydrogen refueling switch capable of switching DC electrical loads, but other options are possible. The interruption contactor 400 may be any suitable contactor having, for example, arc extinguishing capability. In some examples, the interruption contactor 400 may be an open contactor. By extinguishing the arc generated in the interruption contactor 400, damage caused by the arc within the interruption contactor 400 can be advantageously reduced.

[0083] The shut-off contactor 400, as shown in Figure 5, includes a solenoid 416, a plastic arc tray 512, a ceramic capsule 515, an arc blowout magnet 516, pressurized hydrogen 518, a fixed component 520, and a movable component 522. The solenoid 416 can facilitate the opening and closing of the shut-off contactor 400. The operation of the solenoid 416 may, for example, change the position of the movable component 522 relative to the fixed component 520. The plastic arc tray 512 may help contain the arc generated within the shut-off contactor 400. The ceramic capsule 515 can form an envelope that seals the arc generated within the shut-off contactor 400. The ceramic capsule 515 may be gas impermeable, electrically insulating, or any combination thereof. The arc blowout magnet 516 may help control the position of the arc. For example, the arc blowout magnet 516 may help maintain the position of the arc between the fixed component 520 and the movable component 522. Pressurized hydrogen 518 can further facilitate arc direction. Pressurized hydrogen 518 can facilitate arc direction by means of, for example, a plastic arc tray 512, a ceramic capsule 515, an arc blowout magnet 516, or any suitable combination thereof.

[0084] Under normal operation in block 502, coil current is supplied to the solenoid 416 to maintain contact between the movable component 522 and the fixed component 520. This contact allows current to flow through circuits including the interrupting contactor 400 (e.g., circuit 200 in Figure 2, circuit 300 in Figure 3, etc.). A fault current may be generated in the circuits including the interrupting contactor 400. If the fault current increases in block 505, a force may increase between the movable component 522 and the fixed component 520. This force (also referred to herein as "contact levitation") may be a magnetic force caused by the flow of fault current through the interrupting contactor 400.

[0085] A system controller, such as the system controller 106 in Figures 2-3, can detect an increase in fault current as the interruption contactor 400 transitions from normal operation of block 502 to block 505 as the fault current increases. For example, the period of shift between normal operation in block 502 and block 505 as the fault current increases may be approximately 1 millisecond. In a further example, the system controller 106 can detect the increasing fault current within a period of approximately 1 millisecond.

[0086] The system controller 106 can, for example, detect contact lift that separates the movable component 522 from the fixed component 520. The system controller 106 can determine, for example, based on a current measurement 205, that the current is high enough to initiate contact lift in the interrupting contactor 400 included in the interrupting contactor circuit 108. The system controller 106 can then initiate an ultrafast coil turn-off in block 506. During the ultrafast coil turn-off, an arc 525 may begin to form between the movable component 522 and the fixed component 520. The arc 525 can add further pressure to separate the movable component 522 from the fixed component 520. The system controller 106 can discharge the coil current using the interrupting contactor circuit 108, as further described with reference to Figures 5-6. Discharging the coil current can result in a stronger return spring and increased arc pressure in the arc 525. The stronger return spring and increased arc pressure can further separate the movable component 522 from the fixed component 520. The time required to complete the ultrafast coil turn-off could, for example, be about 2 milliseconds after an increase in fault current is detected in block 505.

[0087] In block 508, the arc 525 may be extended to become an extended arc 526. The extended arc 526 can further separate the movable component 522 from the fixed component 520. To facilitate the generation of the extended arc 526 in a direction that further separates the movable component 522 from the fixed component 520, the arc blowout magnet 516 can sequentially move the arc 525 toward the ceramic capsule 515. Pressurized hydrogen 518 can form a dielectric atmosphere within the shut-off contactor 400. The dielectric atmosphere generated within the shut-off contactor 400 can further facilitate the generation of the extended arc 526 in a direction that further separates the movable component 522 from the fixed component 520. The dielectric atmosphere can, for example, absorb arc energy. The duration for generating the extended arc 526 may, for example, be 4 to 5 milliseconds. After block 508, the shut-off contactor 400 may be in an open state. The open state may be a state in which the movable component 522 and the fixed component 520 are separated by a distance sufficient to prevent the flow of fault current to the circuit including the interrupting contactor 400 (for example, circuit 200 in Figure 2, circuit 300 in Figure 3, etc.).

[0088] The ultrafast coil turn-off in block 506 can reduce the total time required to achieve the open state of the interrupting contactor 400 (e.g., circuit 200 in Figure 2, circuit 300 in Figure 3, etc.). This can favorably reduce the risk of damage to the circuit containing the interrupting contactor 400 (e.g., circuit 200 in Figure 2, circuit 300 in Figure 3, etc.). The risk of damage is reduced because at least the interrupting contactor 400 can be opened and insulate downstream components from the fault current. Furthermore, by reducing the total time required to achieve the open state of the interrupting contactor 400, the risk of damage to the interrupting contactor 400 itself can be reduced. This is because, at least, there is less time for the arc to accumulate energy based on the received fault current. With less arc energy, the interrupting contactor 400 can more easily direct the arc energy, as described herein, and damage to the interrupting contactor 400 can be prevented.

[0089] [Example waveforms related to fault circuit handling using a blockage contactor] Figure 6 shows exemplary waveforms related to the processing of a fault circuit using a break-off contactor according to several aspects of the present disclosure. The waveforms shown in Figure 6 include a coil current 600, a break-off contactor arc voltage 602, a power supply voltage 604, a fault current 606, and a fault detection 608.

[0090] Voltage waveforms (e.g., disconnection contactor arc voltage 602, power supply voltage 604, etc.) can correspond to the voltage axis 610. Current waveforms (e.g., coil current 600, fault current 606, etc.) can correspond to the current axis 612. However, other options are also possible. Each waveform can correspond to a different axis, for example. Coil current 600 and fault current 606 can, for example, correspond to current axes of different scales.

[0091] The coil current 600 can represent the coil current supplied to the solenoid (e.g., solenoid 416 in Figure 4) of the interrupting contactor (e.g., interrupting contactor 400 in Figures 4-5). The fault detection 608 may be a digital signal indicating whether a fault has occurred.

[0092] In some examples, fault detection 608 can be based on fault current 606. Fault current can be expressed in amperes. In some examples, the maximum value of fault current 606 may be greater than 10,000 amperes. When fault current 606 reaches a threshold, the system controller (e.g., system controller 106 in Figures 2-3) can detect a fault. The system controller 106 can then change fault detection 608 from a normal state to a fault state. The normal state may be 0, as shown in Figure 6. The fault state may be 1, as shown in Figure 6. However, in some examples, the fault state may be 0 or the fault state may be 1.

[0093] When the system controller 106 changes the fault detection 608 to a fault state, the system controller 106 can further turn off the coil current 600. When the coil current 600 is turned off, the interrupting contactor arc voltage 602 may rise. The interrupting contactor arc voltage 602 can represent the differential voltage between the movable component 422 and the fixed component 420 of the interrupting contactor 400. If the interrupting contactor arc voltage 602 is higher than the power supply voltage 604 of the battery in the circuit, the interrupting contactor 400 can interrupt the fault current, as described with reference to Figures 4 and 5.

[0094] [term] Unless the context clearly requires otherwise, words such as “equipped with” and “include” throughout the description and claims should be interpreted in a comprehensive sense, not exclusive or exhaustive, that is, “includes but not limited to.” The term “combined” as commonly used herein refers to two or more elements that are directly connected or that can be connected by one or more intermediate elements. Similarly, the term “connected” as commonly used herein refers to two or more elements that are directly connected or that can be connected by one or more intermediate elements. Where the context allows, words in the above detailed description that use singular or plural numbers may also include plural or singular numbers. The word “or” referring to a list of two or more items encompasses all interpretations of this word: any of the items in the list, all items in the list, and any combination of items in the list.

[0095] Furthermore, the conditional language used herein, in particular "can," "could," "may," "for example," and "such as," is generally intended to convey that some embodiments include certain features, elements, and / or states, while others do not, unless otherwise specified or understood in the context in which they are used. Therefore, such conditional language is generally not intended to imply that features, elements, and / or states are required in any way in one or more embodiments.

[0096] The above description is based on reference to specific embodiments. However, the above illustrative description is not intended to be exhaustive or to limit the invention to the exact forms described. Many modifications and variations are possible in light of the above teachings. This will enable those skilled in the art to best utilize the technology and various embodiments with various modifications suitable for various applications.

[0097] While the present disclosure and embodiments have been described with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. Such changes and modifications should be understood to be within the scope of the present disclosure.

Claims

1. A system equipped with circuit fault protection, Battery and A disconnecting contactor electrically connected to the battery, wherein the disconnecting contactor is configured to electrically connect the battery to the end of the load in a closed state and to electrically insulate the battery from the end of the load in an open state, A controller, wherein the controller is While the interrupting contactor is in the closed state, a fault is detected in the circuit including the battery and the interrupting contactor. A controller configured to switch the shut-off contactor to the open state in response to the detection of the aforementioned fault, A system that includes these features.

2. The system according to claim 1, wherein the controller is configured to switch the shut-off contactor to the open state in less than one millisecond after detecting the fault.

3. The system according to claim 1, wherein the controller is configured to reduce the coil current of the interrupting contactor by switching at least the state of a transistor in order to switch the interrupting contactor to the open state, and when the coil current of the interrupting contactor is reduced, the interrupting contactor enters the open state.

4. The system according to claim 3, wherein the controller is configured to switch the state of a second transistor in order to reduce the coil current of the cutoff contactor, the second transistor applies a pulse width modulated signal to the circuit during normal operation, and the second transistor is connected to ground.

5. The system according to claim 3, wherein a bus voltage is applied to the interrupting contactor by switching the state of the transistor, and after the application of the bus voltage, the arc voltage of the interrupting contactor is greater than the supply voltage of the battery.

6. The diode in parallel with the transistor is configured to function as a voltage source for the bus voltage applied to the cutoff contactor. The bus voltage applied to the interrupting contactor causes the coil current to flow to ground. The system according to claim 5.

7. The system according to claim 1, further comprising a second disconnection contactor electrically communicating with the battery.

8. The system according to claim 1, wherein the controller is further configured to restore the system to operation after the fault has been resolved.

9. The system according to claim 1, wherein the system is configured to provide circuit fault protection while the controller is not supplied with power.

10. The system according to claim 1, wherein the circuit is fuse-less.

11. A system for controlling circuit faults, Battery and Multiple interruption contactors, wherein the multiple interruption contactors are A first disconnecting contactor configured to electrically connect the battery to the first end of the load in a closed state and to electrically insulate the battery from the first end of the load in an open state, A plurality of interruption contactors, each comprising: a second interruption contactor configured to electrically connect the battery to the second end of the load in a closed state and to electrically insulate the battery from the load in an open state; A control circuit, wherein the control circuit is The first interruption contactor detects a fault while it is in the closed state, A control circuit is configured to switch the first disconnection contactor to the open state in response to the detection of the aforementioned fault, A system that includes these features.

12. The aforementioned control circuit is A first transistor electrically communicating with the first disconnecting contactor, A first diode in parallel with the first transistor, A second transistor connected between the first disconnecting contactor and ground, A third transistor electrically communicating with the second disconnector contactor, A third diode in parallel with the third transistor, The system according to claim 11, further comprising a fourth transistor connected between the second blocking contactor and ground.

13. The system according to claim 11, further comprising a third interruption contactor in series with the first interruption contactor.

14. The system according to claim 11, wherein the control circuit is configured to switch the shut-off contactor to the open state in less than one millisecond after detecting the fault.

15. A method of circuit protection, A step of detecting a fault condition in a circuit including a disconnecting contactor and a battery, wherein the disconnecting contactor is closed to electrically connect the battery terminals to a load during the detection, and the fault condition is related to a fault current applied to the circuit, A method comprising the step of opening the interrupting contactor in response to the detection to electrically isolate the end of the battery from the load, thereby interrupting the fault current.

16. The method according to claim 15, wherein the step of opening the interrupting contactor is performed in less than 1 millisecond after detecting the fault condition.

17. The method according to claim 15, wherein the step of opening the interrupting contactor further includes the step of applying a bus voltage greater than the supply voltage of the battery to the interrupting contactor.

18. The step of applying the bus voltage which is greater than the supply voltage of the battery is, The further step includes switching the state of the transistor, wherein by switching the state of the transistor, the diode in parallel with the transistor functions as a voltage source for the bus voltage applied to the cutoff contactor. The method according to claim 17, wherein the bus voltage applied to the interrupting contactor causes the coil current of the interrupting contactor to flow to ground.

19. The method according to claim 18, wherein the step of applying the bus voltage which is greater than the supply voltage of the battery further includes the step of switching the state of a second transistor, the second transistor applying a pulse width modulated signal to the circuit, and the second transistor is connected to ground.

20. The method according to claim 15, wherein the fault condition is a short circuit.

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