Power Relay Assembly, Its Control Method, and Vehicle Including the Assembly

Abstract

The present invention provides a power relay assembly, a control method thereof, and a vehicle including the assembly. The power relay assembly includes: a first relay and a second relay, the first relay being connected to the positive terminal of a battery; the second relay being connected to the negative terminal of the battery and connected to the first relay via a DC capacitor. A first field effect transistor (FET) is connected in parallel with the first relay, and a second FET is connected in parallel with the first relay and connected in series with the first FET. A voltage control circuit is configured to regulate the voltage of the first FET using a first voltage, or to regulate the voltage of the first FET using a second voltage having a magnitude lower than that of the first voltage.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2020 - 0027327, filed with the Korean Intellectual Property Office on March 4, 2020, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present invention relates to a power relay assembly that controls the power of a high - power and large - capacity battery included in an electric vehicle. Background art

[0004] According to the type of power source that generates driving force, vehicles can be classified into internal combustion engine vehicles, hybrid electric vehicles, and pure electric vehicles. Internal combustion engine vehicles, which are vehicles that generate power by burning fossil fuels, are the most commonly used vehicles. To address the depletion problem of fossil fuels as fuels for internal combustion engine vehicles and environmental pollution problems, hybrid electric vehicles and pure electric vehicles have been developed, and their penetration rates have been gradually increasing.

[0005] Hybrid electric vehicles (HEVs) can be classified into the following two different types. The first type of hybrid electric vehicle is equipped with an electric motor and an internal combustion engine, and uses the driving force of the internal combustion engine or the regenerative energy generated during braking to charge the battery, thereby driving the electric motor. In the second type of hybrid electric vehicle, it is the same as the first type with both an electric motor and an internal combustion engine, but an additional method of charging the battery by supplying power from the outside is added. In other words, the second type of hybrid electric vehicle can receive power from the outside and charge the battery through a plug - in method. This is the plug - in hybrid electric vehicle (PHEV).

[0006] Pure electric vehicles (EVs) have also been developed and sold in various forms. Hydrogen electric vehicles are of such a type that charge the battery by using the electricity generated during the chemical reaction between hydrogen and oxygen, thereby driving the electric motor. These hybrid electric vehicles and electric vehicles use high - power and large - capacity batteries to provide a large amount of power to the electric motor used as a power source. Specifically, the power relay assembly is configured to supply or cut off the high - voltage and large - current power of the battery to the electric motor. In addition, the power relay assembly performs initial charging through pre - charging to prevent damage to the inverter due to high - voltage inrush current before the relay is driven.

[0007] Meanwhile, conventional power relay assemblies for hybrid electric vehicles and electric vehicles use methods including inflatable relays and methods including semiconductor switching elements. The prior art including inflatable relays has the disadvantages of large volume and heavy weight. The problem with the prior art using semiconductor switching elements is that when the battery is charging, the semiconductor switching element may be damaged during the operation of cutting off the power, or the power may not be blocked by the diode provided within the semiconductor element. SUMMARY OF THE INVENTION

[0008] Accordingly, compared with a conventional inflatable relay, one aspect of the present invention provides a power relay assembly capable of reducing weight and size by providing at least two semiconductor switching elements without a pre-charge resistor, a vehicle including the assembly, and a control method of the power relay assembly, and compared with the prior art, provides a power relay assembly, a vehicle including the assembly, and a control method of the power relay assembly, which improve service life and durability by removing sparks generated when the relay is turned on / off.

[0009] According to one aspect of the present invention, a power relay assembly may include: a first relay, a second relay, a first field effect transistor (FET), a second FET, and a voltage control circuit, the first relay being connected to the positive terminal of a battery; the second relay being connected to the negative terminal of the battery and connected to the first relay via a direct current (DC) capacitor; the first FET being connected in parallel with the first relay; the second FET being connected in parallel with the first relay and connected in series with the first FET; the voltage control circuit being configured to adjust the voltage of the first FET using a first voltage or adjust the voltage of the first FET using a second voltage having a magnitude lower than that of the first voltage.

[0010] The voltage control circuit may include a DC / DC converter and at least two semiconductor elements, and may be configured to control the first FET based on the second voltage to charge the DC capacitor. The power relay assembly may further include: a transceiver and a controller, the transceiver being configured to communicate with a battery management system (BMS) that controls the battery; the controller being configured to operate the voltage control circuit based on an on signal or an off signal of the BMS.

[0011] The controller can be configured to collect the output voltage of the DC / DC converter and determine whether the DC / DC converter is normal based on the collected voltage. The controller can be configured to turn on the second relay based on the turn-on signal of the BMS, operate the voltage control circuit to apply a second voltage to the first FET, and turn off the first FET after turning on the first relay. Additionally, the controller can be configured to control the voltage control circuit based on the turn-off signal of the BMS to apply a first voltage to the first FET and the second FET, turn off the first FET and the second FET after turning off the first relay, and turn off the second relay.

[0012] The power relay assembly can further include: a current sensor disposed between the battery and the first relay; the controller can be configured to determine whether the operation is performed normally based on the detection value of the current sensor and send the determination result to the BMS through the transceiver. The magnitude of the second voltage can be determined based on the component characteristics of the first FET and the second FET or the charging time of the DC capacitor.

[0013] The controller can be configured to determine whether the transceiver is normal. When it is determined as a result that the transceiver fails, receive a pulse width modulation (PWM) signal from the BMS and control the voltage control circuit based on the received PWM signal. The controller can be configured to turn on or off the power relay assembly based on the PWM signal, diagnose the failure of the power relay assembly, and turn off the PWM signal based on the diagnosis result.

[0014] According to one aspect of the present invention, a vehicle can include: a motor, a battery, and a power relay assembly; the battery is configured to drive the motor; the power relay assembly is configured to connect the battery and the motor, and the power relay assembly can include: a first relay, a second relay, a first field effect transistor (FET), a second FET, and a voltage control circuit, the first relay is connected to the positive terminal of the battery; the second relay is connected to the negative terminal of the battery and is connected to the first relay via a DC capacitor; the first field effect transistor (FET) is connected in parallel with the first relay; the second FET is connected in parallel with the first relay and is connected in series with the first FET; the voltage control circuit is configured to regulate the voltage of the first FET using a first voltage or regulate the voltage of the first FET using a second voltage with a magnitude lower than that of the first voltage.

[0015] The voltage control circuit may include a DC / DC converter and at least two semiconductor elements, and may be configured to control a first FET based on a second voltage to charge a DC capacitor. The vehicle may further include: a battery management system (BMS) configured to operate the battery; a power relay assembly may include: a transceiver and a controller, the transceiver being configured to communicate with the BMS; the controller being configured to operate the voltage control circuit based on an on signal or an off signal from the BMS.

[0016] The controller may be configured to collect the output voltage of the DC / DC converter and determine whether the DC / DC converter is normal based on the collected voltage. The controller may be configured to turn on a second relay based on an on signal from the BMS, control the voltage control circuit to apply a second voltage to the first FET, and turn off the first FET after turning on a first relay. Additionally, the controller may be configured to control the voltage control circuit based on an off signal from the BMS to apply a first voltage to the first FET and the second FET, turn off the first FET and the second FET after turning off the first relay, and turn off the second relay.

[0017] The vehicle may further include: a current sensor disposed between the battery and the first relay; the controller may be configured to determine whether the operation is performed normally based on a detection value of the current sensor and send the determination result to the BMS through the transceiver. The magnitude of the second voltage may be determined based on the element characteristics of the first FET and the second FET or the charging time of the DC capacitor. The controller may be configured to determine whether the transceiver is normal, and when it is determined as a result of the determination that the transceiver has failed, receive a pulse width modulation (PWM) signal from the BMS and adjust the voltage control circuit based on the received PWM signal.

[0018] According to an aspect of the present invention, a control method for a power relay assembly, the power relay assembly including a first relay connected to the positive terminal of a battery, a second relay connected to the negative terminal of the battery and connected to the first relay through a DC capacitor, a first field effect transistor (FET) connected in parallel with the first relay, and a second FET connected in parallel with the first relay and connected in series with the first FET; the control method may include: receiving a control signal from a BMS configured to control the battery; regulating the voltage of the first FET using a first voltage or regulating the voltage of the first FET using a second voltage having a magnitude lower than that of the first voltage based on the control signal from the BMS. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and / or other aspects of the present invention will become apparent and be more readily understood from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 andFigure 2 is the circuit diagram and control block diagram of the power relay assembly disclosed in the prior art.

[0021] Figure 3 is the structural diagram of the power relay assembly according to an exemplary embodiment.

[0022] Figure 4 is a schematic diagram for describing the pre-charging operation of the power relay assembly according to an exemplary embodiment.

[0023] Figure 5 is a curve graph of the embodiment for determining the magnitude of the pre-charging voltage according to an exemplary embodiment.

[0024] Figure 6A and Figure 6B is a schematic diagram for describing the operation of the power relay assembly operating in the battery discharge state according to an exemplary embodiment.

[0025] Figure 7A and Figure 7B is a schematic diagram for describing the operation of the power relay assembly operating in the battery charging state according to an exemplary embodiment.

[0026] Figure 8 is a schematic diagram for describing the operation of the voltage control circuit according to an exemplary embodiment.

[0027] Figure 9 and Figure 10 is a flowchart of the control method of the power relay assembly according to an exemplary embodiment. Detailed Description

[0028] Throughout the explanatory drawings, the same reference numerals denote the same elements. Not all elements of the exemplary embodiments of the present invention will be described, and descriptions of elements known in the art or elements overlapping with each other in the exemplary embodiments will be omitted. Terms used throughout the specification (such as "~ component", "~ module", "~ member", "~ block", etc.) can be implemented in software and / or hardware, and multiple "~ components", "~ modules", "~ members" or "~ blocks" can be implemented in a single element, or a single "~ component", "~ module", "~ member", "~ block" can include multiple elements.

[0029] It should be understood that when an element is referred to as being "connected" to another element, it can be directly or indirectly connected to other elements, where indirect connection includes "connection" via a wireless communication network. Also, when a component "includes" or "contains" an element, unless there is a contrary specific description, the component can further include other elements without excluding other elements.

[0030] In the specification, it can be understood that when a component is referred to as "above / below another component", it can be directly above / below the other component, or there may also be one or more intermediate components. It should be understood that although the terms first, second, third, etc. used herein may be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0031] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Reference numerals are used for convenience of description and are not intended to indicate the order of each step. Each step may be implemented in an order different from the order shown, unless the context clearly indicates otherwise.

[0032] Hereinafter, the operating principle and implementation embodiments of the present invention will be described with reference to the drawings. Figure 1 and Figure 2 are the circuit diagram and control block diagram of a power relay assembly disclosed in the prior art. To avoid repeated description, the following description will be given.

[0033] First, referring to Figure 1 , the prior art may be a mechanical power relay assembly (hereinafter referred to as the prior art (1)). The prior art (1) may include a first relay 11 corresponding to the main (+) relay, a second relay 12 corresponding to the main (-) relay, a third relay 13 for pre-charging, a pre-charging resistor 3 for suppressing sparks, and a busbar capable of transmitting high power. In addition, the prior art (1) may include a current sensor 14 for measuring the current flowing through the high-voltage battery (B+, B-) during charging or discharging, which may be provided with a cement resistor.

[0034] For example, when the prior art (1) is applied to a hybrid vehicle or the like, the prior art (1) is connected to a DC capacitor 20 for pre-charging, and the DC capacitor 20 may be connected to a motor controller 21 and other loads. When the motor starts to operate, the prior art (1) performs pre-charging before the first relay 11 is turned on to prevent the occurrence of high inrush current and uses the pre-charging resistor 3 to limit the high inrush current.

[0035] The prior art (1) uses an inflatable relay, i.e., the third relay 13, which is filled with a special gas to suppress the sparks that may occur during the on or off operations of the first relay 11 and the second relay 12. The disadvantages of these inflatable relays are their large size and heavy weight. In addition, a magnet must be included in the third relay 13 to control the spread of the sparks, and an additional device is required to ensure the stability of the mechanical structure. This additional device may affect the sensing operation of the current sensor 14, and there is a design constraint that the current sensor 14 and the third relay 13 must be kept at a certain distance. To solve the problems of the prior art (1), the prior art (2) uses semiconductor switching elements instead of the third relay (13).

[0036] Reference Figure 2 , the prior art 2 further includes a first semiconductor element 30 and a second semiconductor element 31 in addition to the first relay 11 and the second relay 12. The first semiconductor element 30 and the second semiconductor element 31 are connected in parallel, and a pre-charge resistor 3 is connected in series with the second semiconductor element 31. The first semiconductor element 30 and the second semiconductor element 31 can be field effect transistors including internal diodes. A PRA controller 40 is provided to operate the first semiconductor element 30 and the second semiconductor element 31. The PRA controller 40 receives signals related to the charging or discharging of the battery from a battery management system (BMS) 50 that controls the battery B. The PRA controller 40 is configured to turn on or off the first relay 11 and the second relay 12, or operate the first semiconductor element 30 and the second semiconductor element 31 for pre-charging.

[0037] To suppress the sparks or arcs that may occur during the on or off operations of the first relay 11 and the second relay 12, the PRA controller 40 makes the two contacts of the relays 11 and 12 have the same electric potential through the first semiconductor element 30 and the second semiconductor element 31, and operates the first relay 11 and the second relay 12. On the other hand, like the prior art (1), the prior art (2) also includes a pre-charge resistor 3 (such as a cement resistor or a PTC (positive temperature coefficient) resistor) for pre-charging.

[0038] In order to solve the problems occurring in the prior art (1), the prior art (2) uses the timing control of semiconductor elements (30, 31) to eliminate the sparks or arcs generated when the relay is turned on or off. However, in the case of a failure where the semiconductor elements do not work, when the BMS 50 cannot diagnose the state of the power relay assembly, if necessary, additional wiring harnesses and additional circuits for diagnosis are required. In addition, even if additional wiring harnesses are installed in case of a failure, when an open circuit or a short circuit occurs in the wiring harness, there will also be a problem of out-of-control of the power relay assembly. An electric vehicle (EV) using high voltage may experience an emergency power-off when supplying power from the battery B to the load. However, in this emergency power-off, the problem of the prior art (2) is that the power cannot be completely cut off by the diodes in the semiconductor elements 30, 31.

[0039] Figure 3 is a structural diagram of a power relay assembly according to an exemplary embodiment.

[0040] The disclosed power relay assembly 10 may include a first relay 11 connected to the positive terminal (B+) of the battery, a second relay 12 connected to the negative terminal (B-) of the battery, a first switch connected in parallel with the first relay, a second switch connected in series with the first switch, and a voltage control circuit (60) that applies a voltage to operate the first switch and the second switch. The first switch and the second switch may be implemented as FETs (field effect transistors) or IGBTs (insulated gate bipolar transistors). Hereinafter, for ease of explanation, the description is based on FETs, but the power assembly 10 may be implemented using IGBTs instead of FETs.

[0041] Reference Figure 3 FIG., the disclosed power relay assembly 10 may include: a first relay 11 connected to the positive terminal (B+) of the battery, a second relay 12 connected to the negative terminal (B-) of the battery, a first FET (field effect transistor 32) connected in parallel with the first relay, a second FET 33 connected in series with the first FET 32, and a voltage control circuit (60) that applies a voltage to operate the first FET 32 and the second FET (33).

[0042] Specifically, compared with the prior art (1), the disclosed power relay assembly 10 compensates for the disadvantages of the mechanical relay by removing the pre-charge resistor 3 and connecting the first FET 32 and the second FET 33 in series. In addition, compared with the prior art (2), the disclosed power relay assembly 10 can completely cut off the power in the case of an emergency power-off during the power supply from the battery B to the load.

[0043] The disclosed power relay assembly 10 may include a BMS 50 and a transceiver 45 configured to transmit (Tx) or receive (Rx) signals. The transceiver 45 may be configured to receive signals related to charging or discharging of the battery transmitted from the BMS 50. Based on the received signals, the controller 40 may be configured to operate the first relay 11, the second relay 12, and the voltage control circuit 60. The transceiver 45 may be configured to communicate with the BMS 50 via various networks, such as vehicle communication (e.g., Controller Area Network (CAN) communication, Local Interconnect Network (LIN) communication, or Ethernet communication) in which the disclosed power relay assembly 10 is provided.

[0044] Meanwhile, to prepare for a communication failure with the BMS 50, the controller 40 may be configured to directly receive a PWM signal from the BMS 50. The controller 40 may be configured to turn on or off the first relay 11 and the second relay 12 according to the PWM duty cycle or period. The disclosed power relay assembly 10 may be provided in the form of a micro control unit (MCU) including the controller 40 and the transceiver 45, enabling a fail-safe operation to prepare for the failure cases mentioned in the prior art (2). The controller 40 may be configured to receive a current detection value through the current sensor 14. The controller 40 may be configured to determine whether to perform a normal operation based on the received current detection value and transmit the current detection value to the BMS 50 via the transceiver 45.

[0045] The pre-charging performed in the disclosed power relay assembly 10 may be executed by the first FET 32 and the second FET 33. Specifically, the voltage control circuit 60 may include a DC / DC converter 61 and may be configured to apply a first voltage (hereinafter referred to as the turn-on voltage) to turn on the first FET 32 or a second voltage (hereinafter referred to as the pre-charging voltage) having a magnitude lower than the turn-on voltage. In other words, the disclosed power relay assembly 10 may be configured to perform pre-charging such that the current is limited by applying a smaller pre-charging voltage. Accordingly, the disclosed power relay assembly 10 may eliminate the pre-charging resistor 3 provided in the prior art (2). The second FET 33 may be used to keep the potentials of the two contacts of the first relay 11 the same when an emergency interruption of the relay is required during charging of the high-voltage battery B. The second FET 33 may also be operated by the controller 40 and the voltage control circuit 60.

[0046] Figure 4 is a schematic diagram for describing the pre-charging operation of the power relay assembly according to an exemplary embodiment. Refer to Figure 4, the controller 40 can be configured to turn on the second relay 12 to charge the DC capacitor 20. Additionally, the controller 40 can be configured to apply a pre-charge voltage to the gate-source of the first FET 32. The controller 40 does not apply a voltage to the second FET 33.

[0047] Since the pre-charge voltage is a voltage whose magnitude is less than the turn-on voltage that the voltage control circuit 60 can apply, the current flowing from the battery B to the capacitor through the first FET 32 is limited. The limited current through the first FET 32 charges the DC capacitor 20 through the internal diode of the second FET 33. When the charging is complete, the two contacts of the first relay 11 become the same potential, and no spark or arc will be generated even when the first relay 11 is turned on. In other words, the disclosed power relay assembly 10 can remove the pre-charge resistor 3 included in the prior art (1) and the prior art (2), thereby reducing the size and weight.

[0048] Figure 5 is a graph of an exemplary embodiment for determining the magnitude of the pre-charge voltage. In Figure 5 the graph, the X-axis is the magnitude of the voltage (unit: V) that can be applied to the first FET 32. The Y-axis is the magnitude of the inrush current (unit: A) flowing from the high-power battery B to the power relay assembly 10 according to the applied voltage.

[0049] As Figure 5 shown, when the first FET 32 is set to the turn-on voltage (15V) to turn on, a very high inrush current of up to 1000A may occur. When such a large inrush current appears during the repeated turn-on or turn-off operations of the first relay 11 and the second relay 12, the stress on the processor or other components in the controller 40 may cause durability problems. Therefore, the disclosed power relay assembly 10 controls the first FET 32 with a pre-charge voltage less than the turn-on voltage (e.g., 3V to 5V).

[0050] At the same time, the magnitude of the pre-charge voltage can vary. The magnitude of the pre-charge voltage should be suitable for protecting the components and elements from the inrush current and should charge the DC capacitor 20 within an appropriate time. Therefore, the magnitude of the pre-charge voltage can be changed according to the characteristics of the components and elements set in the power relay assembly 10 and the capacitance of the DC capacitor 20.

[0051] When the pre-charge voltage is set within the range of about 0V to 3V, the magnitude of the inrush current decreases, but the charging time of the DC capacitor 20 may be delayed. When the pre-charge voltage is set within the range of about 5V to 15V, the magnitude of the inrush current can gradually increase, and damage to the components and elements provided in the power relay assembly 10 may accumulate, and the damage may be transmitted to the load. Therefore, the disclosed power relay assembly 10 can set the pre-charge voltage within the range of about 3 to 5V and apply the pre-charge voltage to the first FET 32 during the pre-charge operation.

[0052] Figure 6A and Figure 6B are schematic diagrams for describing the operation of the power relay assembly operating in the battery discharge state. As referred to above Figure 4 When the DC capacitor 20 is charged due to the pre-charge operation, no spark or arc is generated even when the first relay 11 is turned off. After pre-charging, the battery (B) can be configured to supply power to the load. In other words, when the battery (B) is discharging, the controller 40 can be configured to apply a turn-on voltage (e.g., 15V) to the first FET 32 and turn on the first FET 32. As Figure 6A shown, current flows from the battery B to the load through the internal diodes of the first FET 32 and the second FET 33. Due to the free charges, the two contacts of the first relay 11 have the same electric potential. In other words, even when the first relay 11 is Figure 6B turned off as shown, no arc or spark occurs.

[0053] Figure 7A and Figure 7B are schematic diagrams for describing the operation of the power relay assembly operating in the battery charging state. After pre-charging, power can be supplied to the battery B. In other words, when charging the battery B, the controller 40 can be configured to apply a turn-on voltage (e.g., about 15V) to the second FET 33 and turn on the second FET 33. As Figure 7A shown, current flows to the battery B through the internal diodes of the second FET 33 and the first FET 32. Due to the pre-charge, the two contacts of the first relay 11 have the same electric potential. In other words, even when the first relay 11 is Figure 7B turned off as shown, no arc or spark is generated.

[0054] Figure 8 are schematic diagrams for describing the operation of the voltage control circuit. Refer to Figure 8The voltage control circuit 60 included in the disclosed power relay assembly 10 may include: a DC / DC converter 61, a driver 64, and OP-AMPs 65, 66, wherein the DC / DC converter 61 is configured to convert voltage; the driver 64 is configured to drive at least two semiconductor elements 62, 63 and a first FET 32; the OP-AMPs 65, 66 are configured to detect, compare and determine the turn-on voltage and pre-charge voltage transmitted from the DC / DC converter 61.

[0055] Specifically, the DC / DC converter 61 is as follows Figure 8 The general DC / DC converter shown is sufficient. The DC / DC converter 61 can be configured to change the voltage that can be supplied from the battery B by the controller 40 to the magnitude of the on-voltage or the magnitude of the pre-charge voltage. As described above, the magnitude of the on-voltage can be 15V, or the magnitude of the pre-charge voltage can be set to about 3 to 5V, but it is not limited thereto, and various changes can be made.

[0056] The magnitude of the voltage changed by the DC / DC converter 61 can be detected by the OP-AMPs 65 and 66, and the controller 40 can be configured to determine whether the magnitude of the voltage is normal based on the detection result. When the pre-charging operation is performed according to the control command received from the BMS 50, the controller 40 can be configured to apply the pre-charging voltage to the first FET 32 through the driving driver 64. In addition, when the pre-charging operation is performed Figures 6A to 7B During the above operation, the controller 40 may be configured to apply a turn-on voltage to the first FET 32 through the driver 64. In other words, the controller 40 may be configured to operate the driver 64 so as to perform voltage control between the gate source or the drain source of the first FET 32 with a precharge voltage or a turn-on voltage through at least two semiconductor elements 62 and 63.

[0057] Figure 9 and Figure 10 is a flow chart of a control method of a power relay assembly according to an exemplary embodiment. Figure 9 , the controller 40 may be configured to determine whether the communication state with the BMS 50 is abnormal (step 100). In response to determining that the communication state is abnormal (no in step 100), the controller 40 may be configured to determine whether the communication state with the BMS 50 is abnormal (step 100). Figure 10 Flowchart of the control method (A). If the communication state is normal (Yes in step 100), the controller 40 may be configured to determine whether the DC / DC converter 61 is operating normally (step 110). In response to determining that the DC / DC converter 61 is operating abnormally (No in step 110), the controller 40 may be configured to send a cooperation request for fault protection to the BMS 50 or another ECU in the vehicle 1 (step 111).

[0058] In response to determining that the DC / DC converter 61 is operating normally (Yes in step 110), the controller 40 can be configured to receive a control signal from the BMS 50 (step 112). The on / off operation of the power relay assembly (PRA) 10 of the controller 40 can be performed based on the control signal of the BMS 50 (steps 120, 130). The controller 40 can be configured to turn on the second relay 12 based on the on signal sent by the BMS 50 (step 121). Then, the controller 40 applies a pre-charge voltage to the first FET 32 (step 122).

[0059] As described above, the pre-charge voltage is a voltage with a magnitude lower than the on voltage. The controller 40 can be configured to turn on the first relay 11 (step 123) and turn off the first FET 32 (step 124). Thereby, the disclosed power relay assembly 10 can suppress the occurrence of arcs or sparks even when the first FET 32 is turned off.

[0060] Meanwhile, the controller 40 can be configured to turn on the first FET 32 and the second FET 33 based on the off signal sent by the BMS 50 (step 131). Specifically, the controller 40 can be configured to turn on the first FET 32 and the second FET 33 by applying an on voltage to the first FET 32 and the second FET 33 through the voltage control circuit 60. Thereby, the disclosed power relay assembly 10 can suppress the occurrence of arcs or sparks even when the first FET 32 is turned off. The controller 40 can be configured to turn off the first relay 11 (step 132). Thereafter, the controller 40 can be configured to turn off the first FET 32 and the second FET 33 (step 133), and turn off the second relay 12 (step 134).

[0061] Reference Figure 10 and, the controller 40 can be configured to directly receive a PWM signal from the BMS 50 based on a communication anomaly (step 200). After measuring the PWM signal received from the BMS 50, the controller 40 can be configured to start controlling the on / off operation of the PRA based on the measured PWM duty cycle or period (steps 210, 220). The controller 40 can be configured to determine whether the power relay assembly (PRA) 10 fails (e.g., malfunctions) when performing the Figure 9 described on / off operation of the PRA (steps 211, 212).

[0062] If, during the turn-on operation of the PRA, it is determined that the power relay assembly (PRA) 10 has failed (Yes in step 211), the PWM signal output can be turned off (step 230). In other words, if it is determined that the power relay assembly (PRA) 10 has failed, the controller 40 does not perform other PRA turn-on operations. If the power relay assembly (PRA) 10 has not failed (e.g., is operating normally) (No in step 211), the controller 40 can be configured to continue with the PRA turn-on operation (step 212).

[0063] On the other hand, if the power relay assembly (PRA 10) fails during the turn-off operation of the PRA (e.g., in response to determining a PRA failure) (Yes in step 221), the PWM signal output can be turned off (step 230). In other words, if it is determined that the power relay assembly (PRA) 10 has failed, the controller 40 does not perform other PRA turn-off operations. If the power relay assembly (PRA, 10) has no failure (No in step 221), the controller 40 can be configured to continue with the PRA turn-off operation (step 222).

[0064] The power relay assembly, vehicle including the same, and control method of the power relay assembly according to the disclosed aspects can be provided with at least two semiconductor switching elements, thereby reducing weight and size compared to conventional inflatable relays. The power relay assembly, vehicle including the same, and control method of the power relay assembly according to another aspect can improve service life and durability by eliminating sparks generated during relay turn-on / turn-off compared to the prior art.

[0065] The power relay assembly, vehicle including the same, and control method of the power relay assembly according to another aspect can perform a fail-safe operation through an electronic control unit capable of communicating with a battery management system (BMS) that manages the battery.

Claims

1. A power relay assembly, comprising: A first relay connected to the positive terminal of a battery; A second relay connected to the negative terminal of the battery and connected to the first relay via a DC capacitor; A first switch connected in parallel with the first relay; A second switch connected in parallel with the first relay and connected in series with the first switch; And A voltage control circuit configured to regulate the voltage of the first switch using a first voltage or a second voltage having a magnitude lower than that of the first voltage; Wherein the voltage control circuit includes a DC / DC converter and at least two semiconductor elements, and is configured to control the first switch based on the second voltage to charge the DC capacitor.

2. The power relay assembly according to claim 1, further comprising: A transceiver configured to communicate with a battery management system that controls the battery; And A controller configured to adjust the voltage control circuit based on an on signal or an off signal of the battery management system.

3. The power relay assembly according to claim 2, wherein, The controller is configured to collect the output voltage of the DC / DC converter and determine whether the DC / DC converter is normal based on the collected voltage.

4. The power relay assembly according to claim 2, wherein, The controller is configured to turn on the second relay based on the on signal of the battery management system, operate the voltage control circuit to apply the second voltage to the first switch, and turn off the first switch after turning on the first relay.

5. The power relay assembly according to claim 2, wherein, The controller is configured to operate the voltage control circuit based on the off signal of the battery management system to apply the first voltage to the first switch and the second switch, turn off the first switch and the second switch after turning off the first relay, and turn off the second relay.

6. The power relay assembly according to claim 2, further comprising: A current sensor disposed between the battery and the first relay; Wherein the controller is configured to determine whether the operation is performed normally based on the detection value of the current sensor and send the determination result to the battery management system through the transceiver.

7. The power relay assembly according to claim 1, wherein, The magnitude of the second voltage is determined based on the element characteristics of the first switch and the second switch or the charging time of the DC capacitor.

8. The power relay assembly according to claim 2, wherein The controller is configured to determine whether the transceiver is normal, in response to determining that the transceiver fails, receive a PWM signal from the battery management system, and operate the voltage control circuit based on the received PWM signal.

9. The power relay assembly according to claim 8, wherein, The controller is configured to turn on or off the power relay assembly based on the PWM signal, diagnose a fault of the power relay assembly, and turn off the PWM signal based on the diagnosis result.

10. A vehicle, comprising: An electric motor; A battery configured to drive the electric motor; And A power relay assembly configured to connect the battery and the electric motor; Wherein the power relay assembly includes: A first relay connected to the positive terminal of the battery; A second relay connected to the negative terminal of the battery and connected to the first relay via a DC capacitor; A first switch connected in parallel with the first relay; A second switch connected in parallel with the first relay and connected in series with the first switch; and A voltage control circuit configured to regulate the voltage of a first switch using a first voltage or a second voltage having a magnitude lower than that of the first voltage. Wherein, the voltage control circuit includes a DC / DC converter and at least two semiconductor elements, and is configured to control the first switch based on the second voltage to charge a DC capacitor.

11. The vehicle according to claim 10, further comprising: A battery management system configured to control the battery; Wherein, the power relay assembly includes: A transceiver configured to communicate with the battery management system; and A controller configured to operate the voltage control circuit based on an on signal or an off signal from the battery management system.

12. The vehicle according to claim 11, wherein, The controller is configured to collect the output voltage of the DC / DC converter and determine whether the DC / DC converter is normal based on the collected voltage.

13. The vehicle according to claim 11, wherein, The controller is configured to turn on a second relay based on an on signal from the battery management system, operate the voltage control circuit to apply the second voltage to the first switch, and turn off the first switch after turning on a first relay.

14. The vehicle according to claim 11, wherein, The controller is configured to operate the voltage control circuit based on an off signal from the battery management system to apply the first voltage to the first switch and the second switch, turn off the first switch and the second switch after turning off the first relay, and turn off the second relay.

15. The vehicle according to claim 11, further comprising: A current sensor disposed between the battery and the first relay; Wherein, the controller is configured to determine whether the operation is performed normally based on the detection value of the current sensor and send the determination result to the battery management system through the transceiver.

16. The vehicle according to claim 10, wherein, The magnitude of the second voltage is determined based on the component characteristics of the first switch and the second switch or the charging time of the DC capacitor.

17. The vehicle according to claim 11, wherein, The controller is configured to determine whether the transceiver is normal, in response to determining a failure of the transceiver, receive a PWM signal from the battery management system, and operate the voltage control circuit based on the received PWM signal.

18. A control method for a power relay assembly, the power relay assembly including a first relay connected to the positive terminal of a battery, a second relay connected to the negative terminal of the battery and connected to the first relay through a DC capacitor, a first switch connected in parallel with the first relay, and a second switch connected in parallel with the first relay and connected in series with the first switch, the control method including: Receiving, by a controller, a control signal from a battery management system configured to control the battery; Regulating, by the controller, the voltage of the first switch using a first voltage or a second voltage having a magnitude lower than that of the first voltage based on the control signal of the battery management system; Controlling, by the controller, the first switch based on the second voltage to charge the DC capacitor.

Images