Disconnect device for motor vehicle

Abstract

A disconnect device for a motor vehicle includes a mounting plate having a thermally conductive substrate applied thereto. A first layer of conductive material is applied to the substrate. A semiconductor switch supported on the first layer connects or disconnects an input power source to a load. A second layer of conductive material applied to the substrate is electrically isolated from the first layer. An electronic sensing, control, and protection circuit is supported on the second layer and connected to the semiconductor switch to control operation of the semiconductor switch. A control unit in communication with the electronic sensing, control, and protection circuit via an electrically isolated control path provides control and communication between the electronic sensing, control, and protection circuit and the semiconductor switch.

Description

Technical Field

[0001] The present disclosure relates to an electrical system disconnect device for a motor vehicle for protecting system wiring and components from overvoltage and overcurrent conditions. Background Art

[0002] Disconnect devices include circuit breakers, contactors, and fuses. When it is not desirable to accidentally encounter a full current load on a device in a disconnected state, conventional automatic disconnect devices, such as circuit breakers, are typically used to prevent arcing across the circuit breaker. Conventional fuses can be activated when the rated current load is exceeded, but the fuse reacts to the overcurrent condition through a heat-sensitive material that melts to disconnect the circuit and protect the electrical wiring and components. High voltage (HV) (e.g., >300Vdc), high current (>30A) fuses and circuit breakers are typically bulky, have slow response times of about 5 milliseconds (ms) or more, and are limited in temperature response time and current limit required for the fuse material to heat to the melting temperature. Fuses have several disadvantages. Fuses are passive devices that cannot be reset automatically or otherwise, and the current required to disconnect the fuse, although predetermined, may vary greatly under actual use conditions. Once activated, the fuse needs to be manually replaced, and therefore physical access needs to be set when locating the fuse in the system. Furthermore, under certain fault conditions, such as a HV battery short, fuse response time variations may result in excessive fault currents in a battery powered system, such as that in an electric vehicle.

[0003] Therefore, while current disconnect devices achieve their intended purposes, a need remains for a new and improved disconnect device and method of operating the same. Summary of the invention

[0004] According to several aspects, a disconnect device for a motor vehicle includes a mounting board or printed circuit board having: a semiconductor switch supported on the mounting board to connect or disconnect an input power source to a load; and an electronic sensing, control and protection circuit supported on the mounting board or printed circuit board and connected to the semiconductor switch to control the operation of the semiconductor switch. A control unit communicates with the electronic sensing, control and protection circuit via an electrically isolated control path to provide control and communication between the electronic sensing, control and protection circuit and the semiconductor switch.

[0005] In another aspect of the present disclosure, the electronic sensing, control and protection circuit generates an active control signal to the semiconductor switch.

[0006] In another aspect of the present disclosure, active control defines commanding the active disconnect device to open under a non-electrical fault condition.

[0007] In another aspect of the present disclosure, electronic sensing, control and protection circuits provide for passive or autonomous control of semiconductor switches.

[0008] In another aspect of the present disclosure, the semiconductor switches, electronic sensing, control and protection circuits, and control unit include no moving parts.

[0009] In another aspect of the present disclosure, a non-conductive covering is disposed around the disconnect device, the covering defining a polymeric material.

[0010] In another aspect of the present disclosure, an electrically isolated thermally conductive substrate is applied to a mounting board. A semiconductor switch is mounted to a conductive layer attached to the electrically insulating substrate.

[0011] In another aspect of the present disclosure, a time-varying programmable trip current is applied by a control unit to command the load to disconnect from the power source.

[0012] In another aspect of the present disclosure, the semiconductor switch is operable to turn off within 0.2 ms or less after receiving a turn-off command.

[0013] In another aspect of the present disclosure, the disconnect device transmits the disconnect device status to the control unit via the control path continuously or at predetermined time intervals.

[0014] According to several aspects, a disconnect device for a motor vehicle includes a mounting plate having a thermally conductive and electrically insulating substrate applied thereto. A first layer of conductive material is applied to the substrate. A semiconductor switch supported on the first layer connects or disconnects an input power source to a load. A second layer of conductive material applied to the substrate is electrically isolated from the first layer. An electronic sensing, control, and protection circuit is supported on the second layer and connected to the semiconductor switch to control the operation of the semiconductor switch. A control unit in communication with the electronic sensing, control, and protection circuit via an electrically isolated control path provides control and communication between the electronic sensing, control, and protection circuit and the semiconductor switch.

[0015] In another aspect of the present disclosure, a switch driver and controller connected to the second layer communicates with the semiconductor switches.

[0016] In another aspect of the present disclosure, a switch driver and controller provide built-in sensing and protection to prevent overvoltage and thermal overload during repeated reconnection and disconnection of a load in the event of a fault.

[0017] In another aspect of the present disclosure, the controller includes a trip current-time set point that, when reached, disconnects the load from the input power source.

[0018] In another aspect of the present disclosure, a printed circuit board and a signal connector are connected to the second layer, the printed circuit board providing communication between the power switch and the switch driver and the controller and the signal connector.

[0019] In another aspect of the present disclosure, the signal connector is in communication with a control unit that generates voltage bias power and control signals for operation of the power switch.

[0020] In another aspect of the present disclosure, a first conductive busbar is connected to the first layer, thereby providing a connection to an input power source. A second conductive busbar is connected to the second layer and the load.

[0021] According to several aspects, a method for operating a disconnect device includes: mounting a thermally conductive, electrically insulating substrate to a mounting board; attaching a first layer of conductive material to the substrate; supporting a semiconductor switch on the first layer for connecting or disconnecting an input power source to a load; electrically isolating a second layer of conductive material on the substrate from the first layer; connecting an electronic sensing, control and protection circuit to the second layer and the semiconductor switch to control the operation of the semiconductor switch; and providing a control unit that communicates with the electronic sensing, control and protection circuit via an electrically isolated control path to provide control and communication between the electronic sensing, control and protection circuit and the semiconductor switch.

[0022] In another aspect of the present disclosure, the method further includes generating, by a control unit, a voltage bias power and a control signal for operation of the power switch.

[0023] In another aspect of the present disclosure, the method further includes opening the switch to disconnect the load from the input power source when the load current varies over time by more than a predetermined value under an overload or short circuit condition.

[0024] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0026] Figure 1 is an illustration of a disconnect device according to an exemplary aspect;

[0027] Figure 1a yes Figure 1 Detailed illustration of the disconnect device;

[0028] Figure 1b yes Figure 1 Schematic application of the disconnect device in a load circuit powered by a high voltage battery;

[0029] Figure 2 yes Figure 1 A right perspective view of an exemplary disconnect device;

[0030] Figure 3 yes Figure 2 A top plan view of the disconnect device;

[0031] Figure 4 yes Figure 2 A side partial cross-sectional view of a disconnect device; and

[0032] Figure 5 Yes Figure 2 Front view of the module housing with the disconnect device included. DETAILED DESCRIPTION

[0033] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0034] Reference Figure 1 , a system and method for operating an active disconnect device 10 includes a disconnect device 12 having a low-loss semiconductor switch 14 that connects or disconnects an input power source 16 to an output also defined as a load 18. According to several aspects, the disconnect device 10 may be used to disconnect features or elements of an electrical system of a motor vehicle. The semiconductor switch 14 may include a plurality of semiconductor core tubes that use semiconductor materials (e.g., silicon, silicon carbide, gallium oxide, and gallium nitride) to form a MOSFET or an IGBT. The disconnect device 12 may be capable of blocking high voltages unidirectionally or bidirectionally during a disconnect state. An electronic sensing, control, and protection circuit 20 is connected to the semiconductor switch 14 and provides active-level control or passive-level control operation to the semiconductor switch 14. The electronic sensing, control, and protection circuit 20 communicates with a control unit 22 (e.g., a system controller) via a control path 24 to provide control and communication to the electronic sensing, control, and protection circuit 20. The disconnect device 12 is also connected to a ground 26. According to several aspects, the disconnect device 12 is a resettable, programmable electronic disconnect device without any moving parts.

[0035] Reference Figure 1a and Figure 1b , a schematic diagram of an exemplary active disconnect device 12 suitable for use with a DC load powered by a high voltage (HV) direct current (DC) power source is shown. Figure 1aAs can be seen, the exemplary disconnect device includes a semiconductor power switch 12, a plurality of sensors (including a current sensor 15, a thermal sensor 17, and a voltage sensor 19), a signal interface connector 21, a power supply 23, a switch driver 25, and a control block 27. A single or a plurality of power metal oxide semiconductor field effect transistors (MOSFETs) connected in parallel are used as a power switch 14 between an input terminal 16 and an output terminal 18. The drain of one or more MOSFETs or one or more terminals 1 are connected to the input power terminal 16, and the source of one or more MOSFETs or one or more terminals 2 are connected to the output load terminal 18 through a current sensor 15, which may be a resistor divider, a Hall effect sensor, a magnetoresistive sensor, or other suitable sensor that generates a signal proportional to the current flowing through the switch to the load.

[0036] The signal connector 46 will actively disconnect the connection device 12 from Figure 1 The external controller 22 in the embodiment of the present invention interfaces to receive bias power, ground (Gnd) and command inputs and provide switch state feedback. The bias power supply voltage is 3.3V to 24V relative to ground, more preferably, between 5V and 15V, and is used by a galvanically isolated power supply to generate a regulated power supply (e.g., 5 to 15V) to the sensor, controller and driver circuits, which are referenced to the output terminal 18 or the power switch terminal 2.

[0037] The command signal 27 and the status signal 29 on the system controller side pass through the signal isolator 21 within the switch controller 44 to provide galvanic isolation from the high voltage on the switch terminals, which can operate in the voltage range of 200V to 900V above ground potential. The isolated output command signal 27 is used by the switch control block to actively turn off the power switch via the switch driver. In addition, the switch control block receives output signals from the voltage sensor 19, the current sensor 15, and the temperature sensor 17, and identifies whether there is a fault condition, which will be latched and used to turn off the power switch 12 and reported to the reference through the signal isolator 21 via the status line 56. Figure 3 The system controller 54 is described.

[0038] The controller logic 44, switch driver 25, and signal isolator 21 may be integrated within a single chip integrated circuit (IC) or as a multi-chip module to minimize package size and cost. Passive overvoltage protection circuitry for the power switch 14 may also be incorporated into the active disconnect device 12 in the form of a resistor-capacitor buffer 31 or a transient voltage suppressor (TVS) Zener diode voltage clamp connected across the power switch terminals 1 and 2 to limit transient voltages during load disconnection in the event of an overcurrent fault.

[0039] Figure 1b Also shown is a typical connection of the active disconnect device 12 in a load circuit powered by the HV battery 13. The input terminal 33 is connected to the positive battery terminal 35 and the output terminal 37 is connected to the positive load terminal 37 of the load 18. The signal connector 39 interfaces with the system controller 41 to receive the bias power signal 43, the ground signal 45 and the command signal 47 and transmit the device status feedback 49 through galvanic isolation, as described above. It is also contemplated to use a single signal line that can be used for bidirectional communication of commands and status using open collector type logic signals to minimize cost.

[0040] Reference Figure 2 And refer again Figure 1 The disconnect device 12 may be arranged in a variety of configurations to meet the operational requirements and the spatial envelope allowed by the device. According to several aspects, the disconnect device 12 includes a mounting plate 28, such as made of aluminum, to which an electrically isolated, thermally conductive substrate 30 is applied. A first layer of conductive material 32 (e.g., etched copper) is applied to the substrate 30. A first conductive bus bar 34, such as made of copper, is connected to the first layer 32 and provides a connection to the input power source 16. According to several aspects, reference is made to Figure 1 The depicted semiconductor switch 14 defines a power switch 36 also connected to the first layer 32. According to several aspects, the power switch 36 may be a low-loss power semiconductor switch having predetermined characteristics including but not limited to voltage, current, switching speed, size, etc.

[0041] A second conductive material layer 38 similar to the first layer 32 (e.g., etched copper) is also applied to the substrate 30, which is separated from the first layer 32 and is therefore electrically isolated from the first layer 32. A second conductive busbar 40, such as made of copper, is connected to the second layer 38 and the load 18. A printed circuit board 42, a switch driver and controller 44, and a signal connector 46 are also connected to the second layer 38. The printed circuit board 42 provides communication between the power switch 36 and the switch driver and controller 44 and the signal connector 46. The switch driver and controller 44 provide built-in sensing and protection to prevent overvoltage and thermal overload in the event that the fault load is repeatedly reconnected and disconnected, and may include a trip-current vs. time set point for disconnecting the load 18 from the input power 16. The trip-current vs. time set point may be temperature independent or temperature dependent. The disconnect device 12 has a high sensing speed and a fast response defined as a response time of ≤ 0.2 ms. According to several aspects, the power switch 36 is a low-loss semiconductor switch, which may be a silicon Si insulated gate bipolar transistor (IGBT), SiC metal oxide semiconductor field effect transistor (MOSFET), GaN field effect transistor (FET), etc., with predetermined characteristics, and is coupled with high-speed electronic sensing, control and protection circuits. It is also contemplated that the controller 44 may be replaced with suitable analog and digital logic circuits to implement the protection and fault detection functions required to disconnect the power switch 36. Passive overvoltage protection devices (e.g., resistor-capacitor (RC) snubbers and / or one or more transient voltage suppressor (TVS) devices) may also be incorporated (not shown) across the first and second power terminals of the power switch.

[0042] Reference Figure 3 And refer again Figure 1 and Figure 2 , the power switch 36 may include a plurality of conductor members, including, according to several aspects, a first conductor member 48 defining a first power terminal, a second conductor member 50 defining a second power terminal, and a third conductor member 52 defining a gate or control terminal. The third conductor member 52 is in communication with the driver and controller 44. The controller 44 is also in communication with the signal and power connector 46. The controller 44 and the signal and bias power connector 46 are in communication with a system controller 54, which generates low voltage bias power and control signals ranging from about zero to a bias supply voltage level for operation of the power switch 36, which may typically be between 3.3V and 24V, and more preferably, between 5V and 15V. The signal or communication link 56 provides an electrically isolated communication path between the system controller 54 and the signal connector 46 to receive commands and / or provide status feedback.

[0043] According to several aspects, the device status of the disconnect device 12 may be communicated between the disconnect device 12 and the system controller 54. The device status may include, but is not limited to, whether the power switch 36 is open or closed. The device status may be used by the system controller 54 to generate a control command signal for remotely or automatically closing the power switch 36 to reconnect the disconnect device 12 to the load 18 after a programmable period of time after the disconnect device 12 is disconnected from the load 18. The disconnect device 12 may be disconnected from the power switch 36 due to, for example, an AC or DC high voltage above a predetermined threshold, an overcurrent condition above a predetermined current threshold, or a short circuit fault across the load.

[0044] The system controller 54 may perform a number of functions. These functions include, but are not limited to, commanding the active disconnect device to open under non-electrical fault conditions (e.g., during airbag deployment) to prevent a thermal event. These functions may also include reprogramming the characteristics of the disconnect device 12 if the parameters of the vehicle to which the disconnect device 12 is connected are updated, for example, using an over-the-air signal. These functions may also include commanding the disconnect device 12 to open after an electric vehicle (EV) accident caused by an accelerometer signal to provide overcurrent protection to the battery system to avoid battery failure. According to several aspects, the system controller 54 may be separate from the disconnect device 12 or may be incorporated into the space envelope of the disconnect device 12.

[0045] As previously described, the switch controller 44 and signal connector 46 communicate with the system controller 54, which provides bias power and control signals for operation of the power switch 36. The control signal may be biased, for example, to zero volts or less (defining an open position of the power switch 36), and biased to 5 volts or 12 volts or more (defining a closed position of the power switch 36) using, for example, a pull-up resistor 58 connected to a voltage source 60 (e.g., a 5 volt DC or 12 volt DC source).

[0046] Reference Figure 4 And refer again Figure 2 and Figure 3The voltage drop across the power semiconductor switches 36 within the disconnect device 12 generates heat during operation, so the mounting plate 28 is made of a thermally conductive material to facilitate heat transfer away from the disconnect device 12. To further facilitate heat transfer, the mounting plate 28 may be attached to a heat sink 62 to conduct heat into the heat sink 62 and away from the disconnect device 12 via the mounting plate 28. To provide environmental protection to the disconnect device 12, such as against atmospheric or ambient moisture and against electrical shorts, a non-conductive covering 64, such as a cast, sprayed, or overmolded polymeric or epoxy material, may be provided around the disconnect device 12.

[0047] Reference Figure 5 And refer again Figures 1 to 4 , the disclosed disconnect device 12 may be sized to be incorporated into a common system module housing 66, such as a traction power inverter module (TPIM) for example, vehicle drive motor control, or into a similar module for heating or air conditioning control. The housing 66 includes a port 70 that typically provides access to a fuse, which port 70 may be modified to include the disconnect device 12, thereby eliminating the need for access to remove or replace the disconnect device 12. This prevents environmental factors (such as moisture and dust) from entering the housing 66 and affecting the operation of the disconnect device 12 or other high voltage electrical and electronic components within the housing 66. In addition, with reference to Figure 4 The non-conductive cover 64 further mitigates the effects of environmental factors on the operation of the disconnect device 12. The housing 66 typically includes a power port 72 that provides a sealed connection to the incoming positive and negative high voltage (HV) cables from the HV battery. The housing 66 may also include an output HV port 74 that provides a sealed connection to the outgoing positive and negative high voltage (HV) leads leading to the load. The first power terminal 34 and the second power terminal 40 of the disconnect device 12 are connected between the positive terminal of the input power port 72 and the positive power terminal of the output power port 74, respectively.

[0048] According to several aspects, control circuitry of the controller 44 including the disconnect device 12 provides a time-varying programmable trip current for disconnecting the load 18 from the power source 16 that is substantially independent of temperature. The disconnect device 12 may communicate the disconnect device status to the system controller 54 continuously or at predetermined time intervals. After disconnection by opening the power switch 36, the disconnect device 12 may be reconnected remotely by closing the power switch 36 via a signal from the system controller 54. The disconnect device 12 may also reconnect autonomously, for example, after a predetermined period of time after receiving a switch opening command signal that may be initiated by a signal from the controller 44.

[0049] According to several aspects, the sensing and control features of the disconnect device 12 allow operation at temperature, voltage, and amperage conditions that exceed the known operating limits of the fuse. For example, the disconnect device 12 may operate at up to 125 degrees Celsius, 450V input voltage, and 50Amp output current. The disconnect device 12 may also be programmed to operate above these values ​​for a predetermined period of time without disconnecting the power switch 36, for example, to allow for short periods of rapid vehicle acceleration during operation of the electric vehicle to draw high currents, such as 100Amp.

[0050] The disconnect device 12 of the present disclosure has several advantages. These advantages include a fast active disconnect device without any moving contacts for direct current (DC) or alternating current (AC) high voltage and high current circuits to protect circuits and systems from overcurrent and short circuit faults. The disconnect device uses one or more semiconductor switches of discrete or integrated low loss power with predetermined characteristics (such as voltage, current, switching speed, size, etc.), combined with high-speed electronic sensing, control and protection circuits, to safely disconnect the load from the power supply when the load current varies over time exceeding a predetermined value under overload or short circuit conditions. The disconnect device may obtain a low voltage bias power supply from the system controller and may transmit the disconnect device status to the controller, and can reconnect remotely or autonomously after a programmable or predefined time period. The disconnect device 12 has built-in sensing and / or protection to prevent overvoltage and thermal overload in the event that the faulty load is repeatedly reconnected and disconnected.

[0051] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the gist of the present disclosure are intended to be included within the scope of the present disclosure. Such variations should not be regarded as departing from the spirit and scope of the present disclosure.

Claims

1. A disconnect device for a motor vehicle, comprising: A mounting plate, the mounting plate having: a thermally conductive and electrically insulating substrate applied to the mounting board; a first layer of conductive material applied to the substrate; a semiconductor switch supported on the first conductive material layer, wherein a first power terminal of the semiconductor switch is used to be connected to an input power terminal, a second power terminal of the semiconductor switch is used to be connected to an output load terminal, and the semiconductor switch is configured to connect the input power terminal to the output load terminal or disconnect the input power terminal from the output load terminal; a second layer of conductive material applied to the substrate and electrically isolated from the first layer of conductive material; as well as an electronic sensing, control and protection circuit supported on the second layer of conductive material and connected to a control terminal of the semiconductor switch to control the operation of the semiconductor switch; as well as A control unit communicates with the electronic sensing, control and protection circuit via an electrically isolated control path to provide control and communication between the electronic sensing, control and protection circuit and the semiconductor switch.

2. A disconnect device for a motor vehicle according to claim 1, wherein the semiconductor switch comprises a plurality of semiconductor core tubes, the plurality of semiconductor core tubes using semiconductor materials including silicon, silicon carbide, gallium oxide and gallium nitride to form MOSFET, IGBT or JFET, the disconnect device unidirectionally or bidirectionally blocks high voltage during a disconnect state.

3. The disconnect device of claim 1 , wherein the electronic sensing, control and protection circuit generates active control of the semiconductor switch, and wherein, The active control defines commanding the active disconnect to open under non-electrical fault conditions.

4. A disconnect device for a motor vehicle as claimed in claim 1, wherein the electronic sensing, control and protection circuitry defines passive control of the semiconductor switch.

5. The disconnect device for a motor vehicle of claim 1, wherein the semiconductor switch, the electronic sensing, control and protection circuitry, and the control unit include no moving parts.

6. The disconnect device for a motor vehicle of claim 1, further comprising a non-conductive cover disposed on the disconnect device, the non-conductive cover defining a polymeric material.

7. The disconnect device for a motor vehicle of claim 1, further comprising an electrically isolating, thermally conductive substrate applied to the mounting plate, the semiconductor switch being mounted to the substrate.

8. The disconnect device for a motor vehicle of claim 1, further comprising a time-varying programmable trip current applied by the control unit to command the output load terminals to be disconnected from the input power terminals. 9 . The disconnect device for a motor vehicle according to claim 1 , wherein the semiconductor switch is operable to be disconnected within 0.2 ms or less after receiving a disconnect command.

10. The disconnect device for a motor vehicle according to claim 1, further comprising a disconnect device status, wherein the disconnect device transmits the disconnect device status to the control unit via the control path continuously or at predetermined time intervals.

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