A vehicle-mounted power supply device with bridge arm short circuit protection function, power assembly and electric vehicle

Abstract

This application provides an on-board power supply device, powertrain, and electric vehicle with bridge arm short-circuit protection function, relating to the field of new energy vehicles. It is used to promptly reduce short-circuit current in the event of a bridge arm shoot-through fault, thereby improving the reliability of the on-board power supply device and the driving safety of the electric vehicle. The on-board power supply device includes a bridge arm circuit and a drive circuit. The drive circuit drives the multi-phase bridge arms of the bridge arm circuit to supply power to the load of the electric vehicle. Specifically: one end of the upper bridge arm switch of each phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the upper bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through a feedback resistor; one end of the lower bridge arm switch of each phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the lower bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through another feedback resistor.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle technology, and in particular to an on-board power supply device, powertrain and electric vehicle with bridge arm short-circuit protection function. Background Technology

[0002] With the rapid development of new energy vehicle technology, vehicle electronic control systems are evolving towards high integration. In compact electric vehicles (i.e., Class A electric vehicles), the all-in-one electronic control architecture, with its "high cohesion and low coupling" capabilities, has become a new generation of integrated solutions. This all-in-one electronic control architecture needs to coordinate the collaborative operation of multiple power electronic subsystems, such as the power battery system, motor controller, and vehicle power supply. However, while increasing hardware integration, this architecture places higher demands on the fault isolation capabilities of each subsystem, especially under complex driving conditions, requiring the ability to isolate faults in each subsystem when a partial fault occurs.

[0003] In the operation of an all-in-one electrical control architecture, a shoot-through short-circuit fault in the bridge arm of a power device can pose a system-level safety hazard. For example, if the fault current is not interrupted in time, it may propagate through the shared electrical circuit, causing cascading damage to other subsystems. Therefore, how to reduce the short-circuit current in a timely manner when a shoot-through fault occurs has become an urgent technical problem to be solved. Utility Model Content

[0004] This application provides an on-board power supply device, powertrain, and electric vehicle with bridge arm short-circuit protection function, which is used to reduce the short-circuit current in a timely manner when a bridge arm shoot-through fault occurs, thereby improving the reliability of the on-board power supply device and driving safety.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, an on-board power supply device with bridge arm short-circuit protection function is provided. The on-board power supply device includes a bridge arm circuit and a drive circuit. The drive circuit is used to drive the multi-phase bridge arm of the bridge arm circuit to supply power to the load of an electric vehicle. In this multi-phase bridge arm, one end of the upper bridge arm switch of each phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the upper bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through a feedback resistor. One end of the lower bridge arm switch of each phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the lower bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through another feedback resistor.

[0007] In the above technical solution, two feedback resistors are set in each phase arm of the bridge arm circuit. One feedback resistor is connected between the other end of the upper bridge arm switch and the reference terminal of the drive circuit, and the other feedback resistor is connected between the other end of the lower bridge arm switch and the reference terminal of the drive circuit. Therefore, when any switch in each phase arm experiences a short circuit, the voltage division effect of the feedback resistor changes the reference terminal voltage of the drive circuit, thereby changing the gate-source voltage of the switch that is not short-circuited. When this gate-source voltage is less than the turn-on voltage of the switch, the switch that is not short-circuited can be turned off in time. Compared with the prior art, which requires determining whether a short circuit has occurred based on the sampled current and the reference current, this embodiment does not require an additional current detection module. Closed-loop control of the upper and lower bridge arm switches can be achieved using the inherent characteristics of the feedback resistor. This not only reduces the time delay but also avoids false triggering caused by current ripple, improving the reliability of the on-board power supply device and the driving safety of electric vehicles. Furthermore, compared to current sampling which requires the use of comparators, operational amplifiers, and other devices, the circuit topology provided in this application embodiment is simpler and has lower hardware costs.

[0008] In conjunction with the first aspect, in one implementation, the other end of the upper bridge arm switch is also connected to the reference terminal of the drive circuit via a feedback capacitor. The other end of the lower bridge arm switch is also connected to the reference terminal of the drive circuit via another feedback capacitor.

[0009] Based on the above technical solution, and based on the charging and discharging characteristics of the capacitor, the one feedback capacitor and the other feedback capacitor can suppress the noise generated by the switching transistor during the switching process and maintain the stability of the drive current. Furthermore, during the short circuit period, i.e. when the load current changes suddenly, they provide transient current compensation for the reference terminal voltage of the drive circuit through rapid charging and discharging, thereby improving the gate-source voltage quality of the upper bridge arm switching transistor and the gate-source voltage quality of the lower bridge arm switching transistor, thus improving the reliability of the on-board power supply device and the driving safety of the electric vehicle.

[0010] In conjunction with the first aspect, in one implementation, one end of the upper bridge arm switch is also connected to the output terminal of the drive circuit through a drive resistor; one end of the lower bridge arm switch is also connected to the output terminal of the drive circuit through another drive resistor.

[0011] Based on the above technical solution, the one driving resistor and the other driving resistor can be used to buffer the driving current output by the driving circuit to avoid abnormal fluctuations in the gate voltage caused by parasitic capacitance, effectively eliminate gate voltage oscillation, thereby avoiding false conduction, reducing the probability of bridge arm shoot-through short circuit faults to a certain extent, and improving the reliability of the on-board power supply device and the driving safety of electric vehicles.

[0012] In conjunction with the first aspect, in one implementation, the resistance value of one feedback resistor is positively correlated with the current-carrying capacity of the upper bridge arm switch, and the resistance value of the other feedback resistor is positively correlated with the current-carrying capacity of the lower bridge arm switch.

[0013] Based on the above technical solution, by setting corresponding feedback resistor values ​​according to the current-carrying capacity of the upper and lower bridge arm switching transistors, the overcurrent risk of a single switching transistor under abnormal operating conditions can be limited, thereby reducing the probability of transistor breakdown. Simultaneously, when there is a difference in the current-carrying capacity between the upper and lower bridge arm switching transistors, setting a difference between the resistance values ​​of one and the other feedback resistors can reduce the current deviation between the upper and lower bridge arm switching transistors, avoid excessive local temperature rise, and improve the reliability of the on-board power supply device.

[0014] In conjunction with the first aspect, in one implementation, the resistance values ​​of the one feedback resistor and the other feedback resistor are negatively correlated with the maximum value of the short-circuit current of each phase arm.

[0015] Based on the above technical solution, by setting the resistance value of the feedback resistor according to the maximum value of the short-circuit current, it is possible to avoid the feedback resistor from consuming too much energy and overheating due to excessive short-circuit current. This can reduce the power consumption of the feedback resistor and improve the reliability of the vehicle power supply device while achieving bridge arm short-circuit protection.

[0016] In conjunction with the first aspect, in one implementation, the resistance values ​​of both the feedback resistor and the feedback resistor are greater than 0 and less than or equal to 10 milliohms (mΩ).

[0017] In conjunction with the first aspect, in one implementation, the vehicle power supply device further includes at least one circuit board for carrying electrical components of the vehicle power supply device.

[0018] Based on the above technical solution, the electrical components in the vehicle power supply device can be integrated on a single circuit board or separately integrated on different circuit boards.

[0019] In conjunction with the first aspect, in one implementation, the vehicle power supply device further includes a housing for accommodating the at least one circuit board, the housing also including a power battery interface for connecting a power battery, and an AC interface for receiving AC power.

[0020] Based on the above technical solution, the bridge arm circuit in the vehicle power supply device can be connected to the power battery through the power battery interface, and receive AC power through the AC interface, thereby converting the AC power into DC power to charge the power battery.

[0021] In conjunction with the first aspect, in one implementation, during the process of the on-board power supply receiving AC power and charging the power battery, in response to a short circuit in the upper or lower switch of one phase of the multi-phase bridge arm, the on-board power supply is used to stop charging the power battery.

[0022] Based on the above technical solution, if a short circuit occurs in the upper or lower bridge arm switch of one phase bridge arm in the bridge arm circuit, the bridge arm circuit in the vehicle power supply device can stop working, thereby preventing the bridge arm shoot-through fault from spreading to other bridge arms of the vehicle power supply device and improving the safety and reliability of the vehicle power supply device.

[0023] In conjunction with the first aspect, in one implementation, during the process of the on-board power supply receiving DC power output from the power battery and supplying power to the load, in response to a short circuit in the upper or lower switch of one phase of the multi-phase bridge arm, the on-board power supply is used to stop supplying power to the load.

[0024] Based on the above technical solution, if a short circuit occurs in the upper or lower bridge arm switch of one phase bridge arm in the bridge arm circuit, the bridge arm circuit in the vehicle power supply device can stop working, thereby preventing the bridge arm shoot-through fault from spreading to other bridge arms of the vehicle power supply device and improving the safety and reliability of the vehicle power supply device.

[0025] In a second aspect, a powertrain is provided, the powertrain including an electric motor and an on-board power supply device provided in the first aspect or any implementation thereof, wherein the DC terminal of the on-board power supply device is used to connect to a power battery, and the AC terminal of the on-board power supply device is connected to the electric motor.

[0026] Thirdly, an electric vehicle is provided, the electric vehicle including a power battery and a powertrain provided in the second aspect, the powertrain being connected to the power battery.

[0027] Understandably, the beneficial effects that any of the powertrains and electric vehicles provided above can achieve can be referred to in the context of the beneficial effects of the on-board power supply devices provided above, and will not be repeated here. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the circuit topology for a bridge arm shoot-through protection circuit;

[0029] Figure 2 This is a schematic diagram of the circuit topology of a desaturation protection chip;

[0030] Figure 3 This is a schematic diagram of the circuit topology for another type of bridge arm shoot-through protection circuit;

[0031] Figure 4 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application;

[0032] Figure 5 This is a schematic diagram of the structure of an on-board power supply device provided in an embodiment of this application;

[0033] Figure 6 A schematic diagram of the circuit topology of a bridge arm circuit provided in an embodiment of this application;

[0034] Figure 7 A schematic diagram of a circuit topology for a bridge arm circuit to experience a short circuit, provided in an embodiment of this application;

[0035] Figure 8 A schematic diagram of another bridge arm circuit provided in an embodiment of this application;

[0036] Figure 9 A schematic diagram of the circuit topology of another bridge arm circuit provided in an embodiment of this application;

[0037] Figure 10 A schematic diagram of another circuit topology for a bridge arm circuit to experience a short circuit, provided in an embodiment of this application;

[0038] Figure 11 A timing diagram showing the change of short-circuit current is provided for an embodiment of this application. Detailed Implementation

[0039] The following sections will discuss the fabrication and use of the various embodiments in detail. However, it should be understood that many of the applicable utility model concepts provided in this application can be implemented in a variety of specific environments. The specific embodiments discussed are merely illustrative of specific ways to implement and use this application and technology, and do not limit the scope of this application.

[0040] Unless otherwise defined, all technical terms used herein have the same meaning as commonly known to one of ordinary skill in the art.

[0041] Before introducing the embodiments of this application, the background technology involved in this application will be introduced first.

[0042] With the rapid development of new energy vehicle technology, vehicle electronic control systems are evolving towards high integration. In compact electric vehicles (i.e., Class A electric vehicles), the all-in-one electronic control architecture, with its "high cohesion and low coupling" capabilities, has become a new generation of integrated solutions. This all-in-one electronic control architecture needs to coordinate the collaborative operation of multiple power electronic subsystems, such as the power battery system, motor controller, and on-board power supply.

[0043] While improving hardware integration, this architecture places higher demands on the fault isolation capabilities of each subsystem, especially under complex driving conditions, requiring that each subsystem possess fault isolation capabilities in the event of a partial fault. Currently, in the operation of the all-in-one electronic control architecture, to avoid potential safety hazards caused by the bridge arm shoot-through short circuit fault of power devices, reliable protection is needed when a bridge arm shoot-through short circuit occurs in the power devices.

[0044] The following combination Figures 1 to 3 Examples are given to illustrate several protection schemes for bridge arm through-short circuit faults in related technologies.

[0045] Figure 1 An example circuit topology for a bridge arm shoot-through protection circuit is shown. For example... Figure 1 As shown, the bridge arm shoot-through protection circuit 100 is connected to the bridge arm circuit 200 and is used to turn off the power transistors in the bridge arm circuit 200 when a bridge arm shoot-through fault occurs. The bridge arm shoot-through fault refers to the situation where two switching transistors in the same bridge arm are simultaneously turned on.

[0046] The bridge arm circuit 200 includes a bus capacitor C1 connected between the positive DC bus BUS+ and the negative DC bus BUS-, switching transistors T1 and T2 connected in series between the positive DC bus BUS+ and the negative DC bus BUS-, and switching transistors T3 and T4 connected in series between the positive DC bus BUS+ and the negative DC bus BUS-. A bridge arm shoot-through fault is considered to have occurred when switching transistors T1 and T2 are simultaneously turned on, or when switching transistors T3 and T4 are simultaneously turned on.

[0047] The bridge arm shoot-through protection circuit 100 includes a current sampling unit 101 and a comparison unit 102. The input terminal of the current sampling unit 101 is connected to the bus capacitor C1 of the bridge arm circuit 200, and is used to sample the current of the bus capacitor C1 and output a sampling signal to the comparison unit 102. The comparison unit 102 is connected to the current sampling unit 101, and is used to receive the sampling signal, compare the sampling signal with a set signal, and output a comparison signal to the bridge arm circuit 200. When a bridge arm shoot-through fault occurs in the bridge arm circuit 200, the switching transistor in the bridge arm circuit 200 can be controlled to stop working according to the comparison signal.

[0048] Figure 2 An example circuit topology for a desaturation protection chip is shown. For example... Figure 2As shown, pin C of the desaturation protection chip 300 is connected to the collector of the external switching transistor VT1, pin G of the desaturation protection chip 300 is connected to the base of the external switching transistor VT1, and pin E of the desaturation protection chip 300 is connected to the emitter of the external switching transistor VT1. The desaturation protection chip 300 is used to provide protection when the external switching transistor VT1 desaturates, preventing desaturation faults. A desaturation fault refers to the phenomenon where the switching transistor exits the saturation region when a short circuit occurs; it can also be called a short circuit fault.

[0049] For example, such as Figure 2 As shown, the desaturation protection chip 300 includes a comparator 301, a logic control circuit 302, an internal switching transistor M1, and multiple diodes (e.g., D1, D2, and D3) connected in series. The non-inverting input of the comparator 301, the output of the internal power supply VDD1, the anode of diode D1, and the drain of the internal switching transistor M1 are all connected to node a. The inverting input of the comparator 301 receives a reference voltage Vref. The output of the comparator 301 and the gate of the internal switching transistor M1 are both connected to the logic control circuit 302. The logic control circuit 302 outputs a detection enable signal to the gate of the internal switching transistor M1 based on the output signal of the comparator 301.

[0050] In specific implementation, when the external switch VT1 is in the off state, the internal switch M1 is turned on, and the internal power supply VDD1 is bypassed by the internal switch M1, that is, the potential of node a is clamped to a low potential. At this time, the output signal of comparator 301 does not flip.

[0051] When the external switch VT1 is in the on state, it will first go through a set internal pre-blanking time. After the blanking time, the internal switch M1 is turned off, the internal power supply VDD1 starts to work, and then the voltage of node a is detected. At this time, the output signal of comparator 301 does not flip.

[0052] When a short-circuit fault occurs in the external switching transistor VT1, VT1 will exit the saturation region, and the voltage u between the collector and emitter of the external switching transistor VT1 will decrease. CE As the voltage rises rapidly, diodes D1-D3 are cut off, and the internal power supply VDD1 charges node a. When the threshold of the reference voltage Vref is reached, the output signal of comparator 301 flips, and the external switch VT1 is turned off. The logic control circuit 302 can control the internal switch M1 to turn on based on the output signal of comparator 301 to release the voltage at node a. The voltage u between the collector and emitter of the external switch VT1 is... CE It can be considered as the voltage between node a and node b.

[0053] Figure 3Another circuit topology for the bridge arm shoot-through protection circuit 400 is illustrated. For example... Figure 3 As shown, the bridge arm shoot-through protection circuit 400 is connected to the control terminals of the upper bridge arm switch M2 and the lower bridge arm switch M3, respectively. Taking the bridge arm shoot-through protection circuit 400 connected to the upper bridge arm switch M2 as an example, it includes an operational amplifier 401, a comparator 402, a control chip 403, and a driver chip 404 connected in sequence. To avoid false triggering, the operational amplifier 401 first amplifies the sampled detection current and then outputs the amplified detection current to the comparator 402. Based on the amplified detection current, the comparator 402 compares the detection current with the overcurrent reference current and outputs the comparison signal to the control chip 403. In the event of a short circuit in the upper bridge arm switch M2, the detection current will reach the threshold of the overcurrent reference current. After determining that the detection current is greater than or equal to the overcurrent reference current, the comparator 402 outputs a comparison signal to the control chip 403. The control chip 403 can control the driver chip 404 to output a drive level based on the comparison signal to turn off the upper bridge arm switch M2.

[0054] for Figure 1 The proposed scheme suffers from significant ripple in the bus capacitor C1 during charging and discharging, which can easily lead to overcurrent false triggering. Furthermore, when multiple bus capacitors C1 exist, multiple current sampling units are required for sampling, resulting in high hardware costs. For Figure 2 The proposed solution, however, involves a chip with integrated desaturation functionality that is expensive and has complex blanking time tuning, making it unsuitable for large-scale power module devices. For Figure 3 The scheme shown adds an operational amplifier to the bridge arm shoot-through protection circuit to avoid false triggering, which leads to a large delay in the protection circuit and poses a risk of untimely protection.

[0055] Therefore, this application provides an on-board power supply device with bridge arm short-circuit protection function to solve the problems of high delay, low reliability, and high cost of bridge arm shoot-through protection circuits in related technologies. This allows for timely reduction of short-circuit current in the event of a bridge arm shoot-through fault, improving the reliability of the on-board power supply device and the driving safety of electric vehicles. This on-board power supply device can be applied to applications such as... Figure 4 The electric vehicle shown.

[0056] In one embodiment, such as Figure 4As shown, the electric vehicle 500 includes a power battery 510 and a powertrain 520. The powertrain 520 includes an on-board power supply unit 521 and a motor 522. During operation, the on-board power supply unit 521 can supply the output of the power battery 510 to the motor 522 to drive the electric vehicle 500. Alternatively, during charging, the on-board power supply unit 521 can convert received AC power into DC power to charge the power battery 510. The structure of the on-board power supply unit 521 can be as follows: Figure 5 (a) or Figure 5 As shown in (b) of the diagram.

[0057] In one embodiment, such as Figure 5 As shown in (a) and (b) of this embodiment, the vehicle power supply device 521 provided in this application includes a housing 5211, which includes a power battery interface for connecting a power battery 510 and an AC interface for receiving AC power. The housing 5211 is used to accommodate at least one circuit board ( Figure 5 (Not shown in the diagram), the at least one circuit board is used to carry electrical components of the on-board power supply device 521. For example, the at least one circuit board is used to carry the bridge arm circuit 5212 and the drive circuit 5213, the drive circuit 5213 being used to drive the multi-phase bridge arm of the bridge arm circuit 5212 to supply power to the load of the electric vehicle 500.

[0058] In one embodiment, such as Figure 5 As shown in (a), the on-board power supply device 521 can be an on-board charger (OBC) used to convert the AC power received through the AC interface into DC power to charge the power battery 510 during the charging process of the electric vehicle 500. The OBC includes a power factor correction (PFC) circuit, an alternating current to direct current conversion circuit, and a DC-DC conversion circuit. The multiphase bridge arm in the bridge arm circuit 5212 can be the multiphase bridge arm in the OBC.

[0059] In another embodiment, such as Figure 5 As shown in (b), the on-board power supply device 521 can be a motor control unit (MCU) used to drive the motor 522 to output torque based on the DC power supplied by the power battery 510, so as to drive the electric vehicle 500. The MCU includes a multi-phase bridge arm, and the multi-phase bridge arm in the bridge arm circuit 5212 can be the multi-phase bridge arm in the MCU.

[0060] In another embodiment, the on-board power supply device 521 can be an all-in-one power supply device, that is, the electrical components of the OBC and the MCU are integrated in the housing 5211, and the multi-phase bridge arm in the bridge arm circuit 5212 can be the multi-phase bridge arm in the OBC and the MCU.

[0061] The aforementioned electrical components include switching transistors, resistors, capacitors, and transformers. The switching transistor can be a metal-oxide-semiconductor field-effect transistor (MOSFET), also simply referred to as a MOS transistor, each including a reverse-biased body diode. Alternatively, the switching transistor can also include an insulated-gate bipolar transistor (IGBT) and a diode D, with the collector of the IGBT connected to the cathode of the diode D, and the emitter of the IGBT connected to the anode of the diode D.

[0062] The structure of the electric vehicle 500 and the on-board power supply device 521 provided in the embodiments of this application has been described above. The following section, in conjunction with... Figures 6 to 10 Taking the circuit topology of one phase of the bridge arm circuit 5212 as an example, this paper introduces how the vehicle power supply device 521 provided in the embodiments of this application realizes the function of bridge arm short circuit protection.

[0063] In one embodiment, such as Figure 6 As shown, in the multi-phase bridge arm of the bridge arm circuit 5212, one end of the upper bridge arm switch Q1 of each phase bridge arm is connected to the output terminal OUT of the drive circuit 5213, and the other end of the upper bridge arm switch Q1 of each phase bridge arm is connected through a feedback resistor R. p1 It is connected to the reference terminal GND of the drive circuit 5213. One end of the lower bridge arm switch Q2 of each phase bridge arm is connected to the output terminal OUT of the drive circuit 5213, and the other end of the lower bridge arm switch Q2 of each phase bridge arm is connected to another feedback resistor R. p2 It is connected to the reference terminal GND of the drive circuit 5213.

[0064] The upper bridge arm switch Q1 and the lower bridge arm switch Q2 of each phase bridge arm can be driven by the same driving circuit or by different driving circuits. For example, the upper bridge arm switch Q1 is driven by one driving circuit and the lower bridge arm switch Q2 is driven by another driving circuit.

[0065] As an example and not a limitation, this embodiment uses the example that both the upper bridge arm switch Q1 and the lower bridge arm switch Q2 are NMOS transistors and are driven by the same driving circuit 5213. For ease of description, it is used as... Figure 6Taking the direction shown as an example, Figure 6 A feedback resistor R located at the top p1 This is called the first feedback resistor R. p1 ,Will Figure 6 Another feedback resistor R located below p2 This is called the second feedback resistor R. p2 .

[0066] like Figure 6 As shown, each bridge arm includes an upper bridge arm switch Q1 and a lower bridge arm switch Q2 connected in series. The gates of the upper bridge arm switch Q1 and the lower bridge arm switch Q2 are respectively connected to the output terminal OUT of the drive circuit 5213. The drain of the upper bridge arm switch Q1 is connected to the voltage terminal HV, and the source of the upper bridge arm switch Q1 is connected through the first feedback resistor R. p1 The drain of the lower bridge arm switch Q2 and the reference terminal GND of the drive circuit 5213 are connected respectively. The source of the lower bridge arm switch Q2 is connected through the second feedback resistor R. p2 It is connected to the ground terminal and the reference terminal GND of the drive circuit 5213, respectively.

[0067] In one example, if the upper arm switch Q1 is short-circuited, Figure 6 The circuit topology shown can be equivalent to: Figure 7 The circuit topology shown in (a) is the upper bridge arm switch Q1 and the first feedback resistor R. p1 This can be represented as an equivalent wire, with the source of the lower bridge arm switch Q2 essentially directly connected to the voltage terminal HV. At this time, the short-circuit current I flowing through the lower bridge arm switch Q2... c2 Increase, causing the second feedback resistor R P2 Voltage V across the terminals p2 This also increases the reference terminal GND voltage of the drive circuit 5213. Correspondingly, the voltage difference between the output terminal OUT voltage of the drive circuit 5213 and the reference terminal GND voltage also decreases, which means that the gate-source voltage of the lower bridge arm switch Q2 is reduced. When the gate-source voltage is less than the turn-on voltage of the lower bridge arm switch Q2, the lower bridge arm switch Q2 is turned off.

[0068] In another example, if the lower bridge arm switch Q2 is short-circuited, Figure 6 The circuit topology shown can be equivalent to: Figure 7 The circuit topology shown in (b) is the lower bridge arm switch Q2 and the second feedback resistor R. p2 It can be represented as an equivalent wire, with the first feedback resistor R. p1 The other end is essentially directly connected to the ground terminal. At this time, the short-circuit current I flowing through the upper bridge arm switch Q1... c1 Increase, causing the first feedback resistor R p1 Voltage V across the terminalsp1 This also increases the reference terminal GND voltage of the drive circuit 5213. Correspondingly, the voltage difference between the output terminal OUT voltage of the drive circuit 5213 and the reference terminal GND voltage also decreases, which means that the gate-source voltage of the upper bridge arm switch Q1 is reduced. When the gate-source voltage is less than the turn-on voltage of the upper bridge arm switch Q1, the upper bridge arm switch Q1 is turned off.

[0069] In this embodiment, two feedback resistors are provided in each phase arm of the bridge arm circuit 5212, one of which is a feedback resistor R. p1 Another feedback resistor R is connected between the other end of the upper bridge arm switching transistor Q1 and the reference terminal GND of the drive circuit 5213. p2 The other end of the lower bridge arm switch Q2 is connected between the reference terminal GND of the drive circuit 5213. Thus, when any switch in each phase bridge arm experiences a short circuit, the voltage division effect of the feedback resistor changes the reference terminal GND voltage of the drive circuit 5213, thereby changing the gate-source voltage of the switch that is not short-circuited. When this gate-source voltage is less than the switch's on-state voltage, the switch that is not short-circuited can be turned off in time. Compared to the prior art, which requires determining whether a short circuit has occurred based on the sampled current and the reference current, this embodiment does not require an additional current detection module. The inherent characteristics of the feedback resistor can be used to achieve closed-loop control of the upper bridge arm switch Q1 and the lower bridge arm switch Q2. This not only results in shorter latency but also avoids false triggering caused by current ripple, improving the reliability of the on-board power supply device 521 and the driving safety of the electric vehicle 500. Furthermore, compared to comparators, operational amplifiers, and other devices, the circuit topology provided in this embodiment is simpler and has lower hardware costs.

[0070] In one embodiment, for such Figure 5 The vehicle power supply device 521 shown in (a) is used to stop charging the power battery 510 in response to a short circuit in the upper bridge arm switch Q1 or the lower bridge arm switch Q2 of one phase bridge arm in the multi-phase bridge arm.

[0071] In one embodiment, for such Figure 5 The vehicle power supply device 521 shown in (b) is used to stop supplying power to the load in response to a short circuit of the upper bridge arm switch Q1 or the lower bridge arm switch Q2 in one of the multi-phase bridge arms during the process of receiving DC power output from the power battery 510 and supplying power to the load.

[0072] In other words, if the upper arm switch Q1 or the lower arm switch Q2 of one phase of the bridge arm circuit 5212 is short-circuited, the bridge arm circuit 5212 in the vehicle power supply device 521 can stop working, thereby preventing the bridge arm shoot-through fault from spreading to other bridge arms of the vehicle power supply device 521 and improving the safety and reliability of the vehicle power supply device 521.

[0073] The aforementioned first feedback resistor R p1 The resistance value of the second feedback resistor R p2 The resistance value is related to the current-carrying capacity and short-circuit current of the upper bridge arm switch Q1. In this embodiment, the current-carrying capacity is used to illustrate the current carrying capacity when the switch is fully turned on.

[0074] In one example, the aforementioned first feedback resistor R p1 The resistance value is positively correlated with the current-carrying capacity of the upper bridge arm switch Q1, and the aforementioned second feedback resistor R... p2 The resistance value is positively correlated with the current carrying capacity of the lower bridge arm switch Q2.

[0075] Among them, the first feedback resistor R p1 The resistance value is positively correlated with the current-carrying capacity of the upper bridge arm switch Q1, indicating that the greater the current-carrying capacity of the upper bridge arm switch Q1, the greater the resistance value of the first feedback resistor R. p1 The larger the resistance value, the smaller the current carrying capacity of the upper bridge arm switch Q1, and the larger the first feedback resistor R... p1 The smaller the resistance value, the better. Similarly, the second feedback resistor R... p2 The resistance value of the second feedback resistor R is positively correlated with the current-carrying capacity of the lower bridge arm switch Q2, indicating that the greater the current-carrying capacity of the lower bridge arm switch Q2, the greater the current-carrying capacity of the second feedback resistor R. p2 The larger the resistance value, the smaller the current carrying capacity of the lower bridge arm switch Q2, and the smaller the resistance value of the second feedback resistor R. p2 The smaller the resistance value, the better. Thus, by setting the corresponding feedback resistor values ​​according to the current-carrying capacity of the upper arm switch Q1 and the lower arm switch Q2, the overcurrent risk of a single switch under abnormal operating conditions can be limited, thereby reducing the probability of switch breakdown.

[0076] Meanwhile, if there is a difference in current-carrying capacity between the upper arm switch Q1 and the lower arm switch Q2, for example, if the current-carrying capacity of the upper arm switch Q1 is greater than that of the lower arm switch Q2, then the first feedback resistor R... p1 The resistance value can be greater than that of the second feedback resistor R. p2 The resistance value is determined by setting the first feedback resistor R. p1 Second feedback resistor R p2 The difference in resistance can reduce the current deviation between the upper bridge arm switch Q1 and the lower bridge arm switch Q2, thus avoiding excessive local temperature rise.

[0077] In another example, the first feedback resistor R p1 The resistance value of the second feedback resistor R p2 The resistance value is negatively correlated with the maximum short-circuit current of each phase arm.

[0078] Among them, the first feedback resistor R p1 The resistance value of the first feedback resistor R is negatively correlated with the maximum short-circuit current of each phase arm. The larger the maximum short-circuit current, the greater the resistance value of the first feedback resistor R. p1 The smaller the resistance value, the smaller the maximum short-circuit current, and the smaller the value of the first feedback resistor R. p1 The larger the resistance value, the better. Similarly, the second feedback resistor R... p2 The resistance value of the second feedback resistor R is negatively correlated with the maximum short-circuit current of each phase arm. The larger the maximum short-circuit current, the greater the resistance value of the second feedback resistor R. p2 The smaller the resistance value, the smaller the maximum short-circuit current, and the smaller the value of the second feedback resistor R. p2 The higher the resistance, the better.

[0079] For example, taking a short circuit in the upper bridge arm switch Q1 as an example, based on the relationship between resistance, voltage, and current, when it is necessary to quickly turn off the lower bridge arm switch Q2, the second feedback resistor R... p2 The larger the resistance value, the faster the voltage at the reference terminal GND of the drive circuit 5213 rises, and correspondingly, the faster the lower bridge arm switch Q2 is turned off. However, under conditions of high short-circuit current, the second feedback resistor R... p2 The higher the resistance value, the higher the energy consumption, and there is also the risk of excessive temperature rise. Therefore, when the maximum short-circuit current is high, the second feedback resistor R needs to be reduced. p2 The resistance value is adjusted to avoid high power consumption and overheating. For example, when the vehicle power supply device 521 is an MCU, the short-circuit current may reach about 6000 amperes (A), so the resistance value of the feedback resistor can be in the micro ohm (μΩ) range.

[0080] In one embodiment, the first feedback resistor R p1 The resistance value of the second feedback resistor R p2 The resistance values ​​are all greater than 0 and less than or equal to 10mΩ.

[0081] For example, the first feedback resistor R p1 The resistance value and the second feedback resistor R p2 The resistance values ​​can be the same or different.

[0082] In one example, when there is a difference in the current-carrying capacity of the upper arm switch Q1 and the lower arm switch Q2, a first feedback resistor R can be set. p1 Second feedback resistor R p2The resistance values ​​are different. For example, the first feedback resistor R p1 The second feedback resistor R can be 8 mΩ. p2 It can be 7 mΩ; or, the first feedback resistor R p1 The second feedback resistor R is 6 mΩ. p2 It is 10 mΩ.

[0083] In another example, when there is no difference or negligible difference in the current-carrying capacity of the upper arm switch Q1 and the lower arm switch Q2, a first feedback resistor R can be set. p1 Second feedback resistor R p2 The resistance values ​​are the same. For example, the first feedback resistor R p1 Second feedback resistor R p2 Both can be 5 mΩ; or, the first feedback resistor R p1 Second feedback resistor R p2 Both can be 10 mΩ.

[0084] In one embodiment, such as Figure 8 As shown, the other end of the upper bridge arm switch Q1 is also connected to a feedback capacitor C. a1 It is connected to the reference terminal GND of the drive circuit 5213. The other end of the lower bridge arm switch Q2 is also connected to another feedback capacitor C. a2 It is connected to the reference terminal GND of the drive circuit 5213.

[0085] For ease of description, using Figure 8 Taking the direction shown as an example, Figure 8 A feedback capacitor C located at the top a1 Called the first feedback capacitor C a1 ,Will Figure 8 Another feedback capacitor C located below a2 Called the second feedback capacitor C a2 .

[0086] like Figure 8 As shown, the source of the upper bridge arm switch Q1 is also connected to the first feedback capacitor C. a1 One end is connected to the first feedback capacitor C. a1 The other end is connected to the reference terminal GND of the drive circuit 5213. The source of the lower bridge arm switch Q2 is also connected to the second feedback capacitor C. a2 One end is connected to the second feedback capacitor C. a2 The other end is connected to the reference terminal GND of the drive circuit 5213. For example, the first feedback capacitor C... a1 Second feedback capacitor C a2 The capacitance can be in the nF (nanofa) range.

[0087] Based on the charging and discharging characteristics of a capacitor, the first feedback capacitor C a1 Second feedback capacitor C a2 It can suppress the noise generated by the switching transistor during the switching process and maintain the stability of the drive current. During the short circuit, that is, when the load current changes suddenly, it provides transient current compensation for the reference terminal GND voltage of the drive circuit 5213 through rapid charging and discharging, thereby improving the gate-source voltage quality of the upper bridge arm switch Q1 or the gate-source voltage quality of the lower bridge arm switch Q2.

[0088] In one embodiment, such as Figure 9 As shown, one end of the upper bridge arm switch Q1 is also connected to a drive resistor R. g1 It is connected to the output terminal OUT of the drive circuit 5213; one end of the lower bridge arm switch Q2 is also connected to another drive resistor R. g2 It is connected to the output terminal OUT of the drive circuit 5213.

[0089] For ease of description, using Figure 9 Taking the direction shown as an example, Figure 9 A driving resistor R located at the top g1 Called the first driving resistor R g1 ,Will Figure 9 Another driving resistor R located below g2 This is called the second driving resistor R. g2 .

[0090] like Figure 9 As shown, the first driving resistor R g1 The second drive resistor R is connected between the output terminal OUT of the drive circuit 5213 and the gate of the upper bridge arm switching transistor Q1. g2 It is connected between the output terminal OUT of the driver circuit 5213 and the gate of the lower bridge arm switching transistor Q2. As an example and not a limitation, the first drive resistor R... g1 Second driving resistor R g2 The resistance value can be 11Ω, and the first driving resistor R g1 The resistance value and the second driving resistor R g2 The resistance value is related to the driving capability of the driving circuit 5213, the switching process of the switching transistor, and the voltage spike between the source and drain. This application embodiment will not elaborate on these aspects.

[0091] First driving resistor R g1 Second driving resistor R g2 It can be used to buffer the drive current output of the drive circuit 5213 to avoid abnormal gate voltage fluctuations caused by parasitic capacitance, effectively eliminate gate voltage oscillation, thereby avoiding false turn-on phenomenon and reducing the probability of bridge arm shoot-through short circuit fault to a certain extent.

[0092] Combination Figure 9 , Figure 10 This example illustrates yet another circuit topology where a bridge arm circuit experiences a short circuit. Figure 10 Example (a) illustrates the case of a short circuit in the lower bridge arm switch Q2. Figure 10 (b) is the equivalent circuit diagram of (a).

[0093] The following are Figure 10 Taking the circuit topology where a short circuit occurs as an example, combined with... Figure 11 This describes the changes in short-circuit current during bridge arm short-circuit protection. Specifically, V... gs1 This represents the drive voltage (V) for the upper bridge arm switch Q1. p1 Represents the first feedback resistor R p1 The voltage across the terminals, I c1 This represents the short-circuit current passing through the upper bridge arm switch Q1 when the lower bridge arm switch Q2 is short-circuited.

[0094] In one embodiment, during the time interval 0-t1, the short-circuit current Ic1 rises sharply, at which point the first feedback resistor R... p1 Voltage V across the terminals p1 It continues to rise. At time t1, the driving voltage V gs1 Reaching peak voltage U gs_m The driving voltage V of the upper bridge arm switch Q1 gs1 The self-saturation region transitions into the linear region. At time t2, the short-circuit current I... c1 Reaching peak current I m This is because the small-signal model of the switching transistor exhibits capacitive characteristics, meaning the short-circuit current Ic1 reaches the peak current Ic1. m The timing will lag behind the drive voltage V gs1 Reaching peak voltage U gs_m The time lag is t2-t1. Simultaneously, at time t2, the first feedback resistor R... p1 Voltage V across the terminals p1 It also reached its peak U p1_m This enables control of short-circuit current I. c1 Suppression. During times t2-t3, the upper bridge arm switch Q1 is controlled by the first feedback resistor R. p1 Turn-off under feedback, short-circuit current I c1 It decreased rapidly.

[0095] In another embodiment, if Figure 6 Taking the circuit topology shown as an example, without a feedback capacitor, although the power quality of the gate-source voltage during the short circuit will be reduced, the protection speed can be improved to a certain extent, that is, the duration between 0 and t2 is shortened.

[0096] This application also provides a powertrain, the structure of which can be referred to... Figure 4 and Figure 5 (b) of the above embodiments. The powertrain 520 includes an electric motor 522 and an on-board power supply device 521 as described in the above embodiments. Figure 5 As shown in (b), the DC terminal of the vehicle power supply device 521 is used to connect to the power battery 510, and the AC terminal of the vehicle power supply device 521 is connected to the motor 522.

[0097] The above detailed description of the vehicle power supply device 521 and the analysis of its beneficial effects can be applied to the powertrain, and will not be repeated here in the embodiments of this application.

[0098] This application also provides an electric vehicle, the structure of which can be referred to... Figure 4 The electric vehicle 500 includes a power battery 510 and a powertrain 520, with the powertrain 520 connected to the power battery 510. The powertrain 520 is used to drive the electric vehicle 500 using electrical energy provided by the power battery 510.

[0099] The above detailed description of the vehicle power supply device 521 and the analysis of its beneficial effects can be applied to electric vehicles, and the embodiments of this application will not be repeated here.

[0100] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A vehicle-mounted power supply device with bridge arm short-circuit protection function, characterized in that, The on-board power supply device includes a bridge arm circuit and a drive circuit. The drive circuit is used to drive the multi-phase bridge arm of the bridge arm circuit to supply power to the load of the electric vehicle, wherein: One end of the upper bridge arm switch of each phase bridge arm in the multi-phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the upper bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through a feedback resistor. One end of the lower bridge arm switch of each phase bridge arm is connected to the output terminal of the drive circuit, and the other end of the lower bridge arm switch of each phase bridge arm is connected to the reference terminal of the drive circuit through another feedback resistor.

2. The on-board power supply device according to claim 1, characterized in that The other end of the upper bridge arm switch is also connected to the reference terminal of the drive circuit through a feedback capacitor; the other end of the lower bridge arm switch is also connected to the reference terminal of the drive circuit through another feedback capacitor.

3. The on-board power supply device according to claim 1 or 2, characterized in that, One end of the upper bridge arm switch is connected to the output terminal of the drive circuit through a drive resistor; One end of the lower bridge arm switch is connected to the output of the drive circuit through another drive resistor.

4. The on-vehicle power supply device according to claim 1 or 2, characterized by The resistance value of one feedback resistor is positively correlated with the current-carrying capacity of the upper bridge arm switch, and the resistance value of the other feedback resistor is positively correlated with the current-carrying capacity of the lower bridge arm switch.

5. The on-vehicle power supply device according to claim 1 or 2, characterized by The resistance values ​​of the one feedback resistor and the other feedback resistor are negatively correlated with the maximum short-circuit current of each phase arm.

6. The on-vehicle power supply device according to claim 1 or 2, characterized by The resistance values ​​of both the first and second feedback resistors are greater than 0 and less than or equal to 10 milliohms.

7. The on-vehicle power supply device according to claim 1 or 2, characterized by The vehicle power supply device also includes at least one circuit board, which carries the electrical components of the vehicle power supply device.

8. The on-board power supply device according to claim 7, characterized in that The vehicle-mounted power supply device also includes a housing for accommodating the at least one circuit board, and the housing also includes a power battery interface for connecting a power battery and an AC interface for receiving AC power.

9. The on-vehicle power supply device according to claim 1 or 2, characterized by During the process of the on-board power supply receiving AC power and charging the power battery, in response to a short circuit in the upper or lower bridge arm switch of one phase of the multi-phase bridge arm, the on-board power supply is used to stop charging the power battery.

10. The in-vehicle power supply device according to claim 1 or 2, characterized by During the process of the on-board power supply device receiving DC power output from the power battery and supplying power to the load, in response to a short circuit in the upper or lower bridge arm switch of one phase of the multi-phase bridge arm, the on-board power supply device is used to stop supplying power to the load.

11. A powertrain, characterized by, The powertrain includes an electric motor and an on-board power supply device as described in any one of claims 1-10, wherein the DC terminal of the on-board power supply device is used to connect to the power battery, and the AC terminal of the on-board power supply device is connected to the electric motor.

12. An electric vehicle characterized by comprising: The electric vehicle includes a power battery and the powertrain as described in claim 11, wherein the powertrain is connected to the power battery.

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