Dual bus battery pre-charge circuit

Abstract

Vehicle (112), comprising: a pre-charging circuit designed to selectively couple a resistor (202, 302, 402) via either a first (206, 306, 406) or a second contactor (208, 308, 408) designed to selectively couple terminals of a battery (124) to a load bus (152); and a controller (220, 320, 420) programmed to couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in response to a pre-charge request in a case where the first contactor (206, 306, 406) is closed when commanded to open and the second contactor (208, 308, 408) is open, in order to pre-charge the load bus (152), characterized by the fact that The controller (220, 320, 420) is further programmed to, in response to the pre-charge request in a case where both the first contactor (206, 306, 406) and the second contactor (208, 308, 408) are open and following an immediately preceding pre-charge request that resulted in the resistor (202, 302, 402) being coupled via the first contactor (206, 306, 406), couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in order to pre-charge the load bus (152).

Description

TECHNICAL AREA

[0001] The application generally concerns a pre-charging circuit between a traction battery and high-voltage electrical components in a vehicle. GENERAL STATE OF THE ART

[0002] Electrified vehicles contain high-voltage components connected to a high-voltage bus. They also include a high-voltage battery connected to the bus to provide power to these components. When the vehicle is not in operation, the battery is disconnected from the bus. One or more main contactors may be electrically connected between the bus and the battery. These contactors are controlled to connect and disconnect the battery and bus. Large inrush currents can occur when connecting the battery to the bus.

[0003] In the generic publication DE 10 2014 218 850 A1, a battery arrangement is described in which switches of the battery arrangement are opened and closed to avoid inrush current spikes. Further prior art relating to the background of the invention is provided in publication DE 10 2011 108 408 A1. SUMMARY

[0004] A vehicle includes a pre-charging circuit designed to selectively connect a resistor via either a first or a second contactor, which are designed to selectively connect terminals of a battery to a load bus. The vehicle further includes a controller programmed to connect the resistor via the second contactor in response to a pre-charging request, in a case where the first contactor is closed when commanded to open and the second contactor is open, in order to pre-charge the load bus.

[0005] The controller can further be programmed to couple the resistor across the first contactor to precharge the load bus in response to a precharge request when the first contactor is open and the second contactor is closed. The controller is also programmed to couple the resistor across the second contactor to precharge the load bus in response to a precharge request when both the first and second contactors are open, and when this request follows an immediately preceding precharge request that resulted in the resistor being coupled across the first contactor.The controller can also be programmed to couple the resistor via the first contactor in order to precharge the load bus in response to the precharge request in a case where both the first and second contactors are open and that it follows an immediately preceding precharge request which resulted in the resistor being coupled via the second contactor.

[0006] One method involves coupling a resistor across a first contactor, which is connected between the negative terminals of a battery and a load bus, in response to a pre-charge request and the fact that a second contactor, which is connected between the positive terminals of the battery and the load bus, is short-circuited when commanded to open. The method further involves coupling the resistor across the second contactor in response to the pre-charge request and the fact that the second contactor is open.

[0007] The coupling of the resistor via the second contactor also occurs in response to the preload request following an immediately preceding preload request that resulted in the resistor being coupled via the first contactor. The method may further include coupling the resistor via the second contactor in response to the preload request and the fact that the first contactor is short-circuited when commanded to open. The method may further include coupling the resistor via the first contactor in response to both the first and second contactors being open and the preload request following an immediately preceding preload request that resulted in the resistor being coupled via the second contactor.

[0008] A vehicle includes a pre-charging circuit designed to selectively connect a resistor via either a first or a second contactor, which are designed to selectively connect terminals of a battery to a load bus. The vehicle further includes a controller programmed to connect the resistor via the second contactor in response to a pre-charging request that follows an immediately preceding pre-charging request that resulted in the resistor being connected via the first contactor, in order to pre-charge the load bus.

[0009] The controller can further be programmed to couple the resistor via the first contactor in response to the pre-charge request that follows the immediately preceding pre-charge request that caused the resistor to be coupled via the first contactor, and to ensure that the second contactor is closed when commanded to open. The controller can further be programmed to couple the resistor via the first contactor in response to the pre-charge request that follows the immediately preceding pre-charge request that caused the resistor to be coupled via the second contactor, in order to pre-charge the load bus.The control can furthermore be programmed to couple the resistor via the second contactor in response to the pre-charge request that follows the immediately preceding pre-charge request that caused the resistor to be coupled via the second contactor and to the fact that the first contactor is closed when it is commanded to open.

[0010] The pre-charging circuit can include a first switching device designed to selectively couple the resistance between a positive terminal of the battery and a positive terminal of the load bus, and a second switching device designed to selectively couple the resistance between a negative terminal of the battery and a negative terminal of the load bus. The first switching device can be a p-channel metal-oxide-semiconductor field-effect transistor (MOSFET), and the second switching device can be an n-channel MOSFET.The pre-charge circuit may further include a first diode coupled between the resistor and the positive terminal of the load bus, designed to conduct current when the first switching device selectively couples the resistor, and a second diode coupled between the resistor and the negative terminal of the load bus, designed to conduct current when the second switching device selectively couples the resistor. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 represents one possible configuration of an electrified vehicle. Fig. Figure 2 represents a possible configuration of a vehicle high-voltage system that has a pre-charge resistor for each bus contactor. Fig. Figure 3 represents a possible configuration of a vehicle high-voltage system that has a single resistor which can be coupled via each of the bus contactors. Fig. Figure 4 represents a possible configuration of a vehicle high-voltage system that has a single pre-charge resistor which can be coupled via solid-state switching devices through each of the bus contactors. Fig. Figure 5 shows a flowchart of a possible sequence of operations for controlling the pre-charging operation of the high-voltage system. DETAILED DESCRIPTION

[0011] Embodiments of the present disclosure are described herein. However, it is understood that the disclosed embodiments are merely examples and that other embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be enlarged or reduced to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis to teach the person skilled in the art the diverse uses of the present invention. It is understood by the average person skilled in the art that various features illustrated and described with respect to any of the figures can be combined with features illustrated in one or more other figures to create embodiments that are not explicitly illustrated or described.The combinations of illustrated features provide representative embodiments for typical applications. However, various combinations and modifications of the features, consistent with the teachings of this disclosure, might be desirable for certain applications or implementations.

[0012] Fig. Figure 1 shows an electrified vehicle 112, which can be referred to as a plug-in hybrid electric vehicle (PHEV). A plug-in hybrid electric vehicle 112 can include one or more electric machines 114 mechanically coupled to a transmission or hybrid transmission 116. The electric machines 114 can be capable of operating as an electric motor and generator. Furthermore, the hybrid transmission 116 is mechanically coupled to an internal combustion engine 118. The hybrid transmission 116 is also mechanically coupled to a drive shaft 120, which is mechanically coupled to the wheels 122. The electric machines 114 can provide propulsion and braking capabilities when the engine 118 is switched on or off.The electric machines 114 can also function as generators and provide fuel efficiency benefits by recovering energy that would normally be lost as heat in a friction braking system. The electric machines 114 can also reduce vehicle emissions by allowing the combustion engine 118 to operate at more efficient speeds and by enabling the hybrid electric vehicle 112 to operate in electric mode with the combustion engine 118 switched off under certain conditions. An electrified vehicle 112 can also be a battery electric vehicle (BEV). In a BEV configuration, the engine 118 may not be present. In other configurations, the electrified vehicle 112 can be a full hybrid electric vehicle (FHEV) without plug-in capability.In other configurations, the vehicle 112 can be a fuel cell electric vehicle (FCEV).

[0013] A battery pack or traction battery 124 stores energy that can be used by the electric machines 114. The traction battery 124 can provide a high-voltage direct current (DC) output. A contactor module 142 can include one or more contactors designed to disconnect the traction battery 124 from a high-voltage bus or load bus 152 when the latter is open, and to connect the traction battery 124 to the high-voltage load bus 152 when the latter is closed. The high-voltage load bus 152 can include power and return conductors for transporting current over the high-voltage load bus 152. The contactor module 142 can be located inside the traction battery 124. One or more power electronics modules 126 (also known as inverters) can be electrically coupled to the high-voltage load bus 152.The power electronics modules 126 are also electrically coupled to the electric machines 114 and provide the capability to transfer energy bidirectionally between the traction battery 124 and the electric machines 114. For example, a traction battery 124 can provide a DC voltage, while the electric machines 114 can be operated with three-phase alternating current (AC). The power electronics module 126 can convert the DC voltage into three-phase alternating current to power the electric machines 114. In a regeneration mode, the power electronics module 126 can convert the three-phase AC current from the electric machines 114, which function as generators, into the DC voltage compatible with the traction battery 124.

[0014] In addition to providing propulsion energy, the traction battery 124 can provide energy for other electrical vehicle systems. The vehicle 112 can include a DC / DC converter module 128, which converts the high-voltage DC output of the high-voltage load bus 152 into a low-voltage DC level of a low-voltage bus 154, compatible with low-voltage loads 156. An output of the DC / DC converter module 128 can be electrically connected to an auxiliary battery 130 (e.g., a 12 V battery) for charging the auxiliary battery 130. The low-voltage loads 156 can be electrically connected to the auxiliary battery 130 via the low-voltage bus 154. One or more high-voltage electrical loads 146 can be connected to the high-voltage load bus 152. The electrical high-voltage loads 146 may have an associated control system which may operate and control the electrical high-voltage loads 146.Examples of high-voltage electrical loads 146 could be a blower, an electric heating element and / or an air conditioning compressor.

[0015] The electrified vehicle 112 can be designed to recharge the traction battery 124 via an external power source 136. The external power source 136 can be a connection to a wall socket. The external power source 136 can be electrically connected to a charging station or an electric vehicle supply equipment (EVSE) 138. The external power source 136 can be an electrical power distribution network, such as that provided by an electricity utility. The EVSE 138 can provide circuitry and controls to regulate and manage the transfer of energy between the power source 136 and the vehicle 112. The external power source 136 can supply electrical power to the EVSE 138 as DC or AC. The EVSE 138 can have a charging plug 140 for connecting to a charging port 134 of the vehicle 112.The charging port 134 can be any type of connector designed to transfer power from the EVSE 138 to the vehicle 112. The charging port 134 can be electrically coupled to an in-vehicle power conversion module or an in-vehicle charging device 132. The charging device 132 can condition the power supplied by the EVSE 138 to provide the correct voltage and current levels to the traction battery 124 and the high-voltage load bus 152. The charging device 132 can interface with the EVSE 138 to coordinate the delivery of power to the vehicle 112. The EVSE connector 140 can have pins that mate with corresponding recesses in the charging port 134. Alternatively, various components described as electrically coupled or connected can transfer power using wireless inductive coupling.

[0016] One or more wheel brakes 144 may be provided to decelerate the vehicle 112 and prevent it from moving. The wheel brakes 144 may be hydraulically actuated, electrically actuated, or a combination thereof. The wheel brakes 144 may be part of a braking system 150. The braking system 150 may include other components for actuating the wheel brakes 144. For simplicity, the figure shows a single connection between the braking system 150 and one of the wheel brakes 144. A connection between the braking system 150 and the other wheel brakes 144 is implied. The braking system 150 may include a control unit to monitor and coordinate the braking system 150. The braking system 150 can monitor the braking components and control the wheel brakes 144 to decelerate the vehicle.The brake system 150 can respond to driver commands and can also operate autonomously to implement functions such as vehicle dynamics control. The brake system 150's control unit can execute a procedure for applying a requested braking force when requested by another control unit or sub-function.

[0017] Electronic modules in the vehicle 112 can communicate via one or more vehicle networks. The vehicle network can include a variety of communication channels. One channel of the vehicle network can be a serial bus, such as a Controller Area Network (CAN). One of the vehicle network channels can be an Ethernet network as defined by IEEE Standards Group 802. Additional vehicle network channels can include discrete connections between modules and can carry power signals from the auxiliary battery 130. Different signals can be transmitted over different channels of the vehicle network. For example, video signals can be transmitted over a high-speed channel (e.g., Ethernet), while control signals can be transmitted over a CAN bus or discrete signals.The vehicle network can include any hardware and software components that support the transmission of signals and data between modules. The vehicle network is in . Fig. Figure 1 is not shown, but it can be implied that the vehicle network can connect to any electronic module present in the vehicle. A Vehicle System Controller (VSC) may be present to coordinate the operation of the various components.

[0018] Fig. Figure 2 represents a configuration of a high-voltage power distribution system 200 for a vehicle, which includes a plurality of contactors for coupling the traction battery 124 to high-voltage electrical loads 218. A contactor module 242 can include a positive-side pre-charge switch 204, which is electrically connected in series with a positive-side pre-charge resistor 202. The contactor module 242 can include a main contactor 206, which is designed to selectively electrically couple a positive terminal 222 of the traction battery 124 to a positive-side conductor 152A of the high-voltage load bus 152. The circuit path, which includes the positive-side pre-charge switch 204 and the positive-side pre-charge resistor 202, can be coupled in parallel with the main contactor 206 between the positive terminal 222 and the positive-side conductor 152A.

[0019] The contactor module 242 can include a feedback contactor 208, which is designed to selectively electrically couple a traction battery feedback terminal 224 (return terminal of the traction battery 124) to a feedback-side conductor 152B of the high-voltage load bus 152. The contactor module 242 can include a feedback-side pre-charge switch 212, which is electrically connected in series with a feedback-side pre-charge resistor 210. The circuit path, which includes the feedback-side pre-charge switch 212 and the feedback-side pre-charge resistor 210, can be coupled in parallel with the feedback contactor 208 between the feedback terminal 224 and the feedback-side conductor 152B.The positive-side pre-charge resistor 202 and the feedback-side pre-charge resistor 210 can be designed to limit the current flowing through the high-voltage load bus 152 during starting when the traction battery 124 is first connected to the high-voltage load bus 152.

[0020] The contactors (e.g., 206 and 208) and switches (e.g., 204 and 212) can be electromagnetic switches, such as relays. The electromagnetic switches may include a coil that opens or closes an associated switch when energized. For example, the contactors and switches may be normally open devices, so that the circuit path opens when the coil is de-energized and closes when the coil is energized. An inductor can be energized by applying a voltage across it to cause a current to flow through it. The inductors may be electrically coupled to a contactor control unit 220, which is designed to supply voltage and current to the inductors.In some configurations, the contactors and switches can be solid-state devices, such as an insulated-gate bipolar transistor (IGBT) or similar devices. The contactor control 220 can be designed to drive the coils and / or solid-state devices via hardware components and software functions. In some configurations, the contactor control 220 can be integrated into another control unit in the vehicle (e.g., system control 148).

[0021] The electrical loads 218 may include capacitive elements that have not been charged. For example, a capacitor may be connected via the terminals of the high-voltage load bus 152 to smooth the voltage. A pre-charge operation can be performed when electrical loads 218 are connected to the high-voltage load bus 152. The purpose of the pre-charge operation is to limit the large initial current flow (e.g., inrush current) that can occur when a voltage is applied to the capacitive loads. The pre-charge operation protects the main contactor 206 and the feedback contactor 208 from excessive inrush currents. Without a pre-charge operation, the main contactor 206 and the feedback contactor 208 would be closed and exposed to the entire inrush current. Consequently, since the main contactor 206 and the feedback contactor 208 close, arcing can occur when the contactors close.This formation of arcs can adversely affect the contactors. For example, excessive inrush currents can cause a contactor to weld itself shut in the closed position. Pre-charging is performed to reduce the occurrence of such events. Furthermore, arcing and welding can occur if the contactor is ordered to open while current is flowing. Normal shutdown procedures can check whether the current is below a certain threshold before the contactors are opened.

[0022] The pre-charging cycle can be initiated if the traction battery 124 is disconnected from the high-voltage load bus for longer than a predetermined period. The pre-charging cycle can also be initiated if the voltage of the high-voltage load bus 152 falls below the voltage of the traction battery by an amount greater than a predetermined amount. Pre-charging can be initiated if the contactors (e.g., 206 and 208) are open during an immediately preceding time interval. Pre-charging can also be initiated when the vehicle is switched on or the ignition is turned on.

[0023] When the system is switched on, all contactors can be in an open state. This means that the traction battery 124 is decoupled or disconnected from the high-voltage load bus 152. The pre-charging operation can involve closing one or more of the positive-side pre-charge switches 204 and the return-side pre-charge switches 212 before closing the main contactor 206 and the return contactor 208. Closing the positive-side pre-charge switch 204 couples the positive-side pre-charge resistor 202 in the conductive path between the traction battery 124 and the high-voltage load bus 152. The positive-side pre-charge resistor 202 limits the current flow from the traction battery 124 to the electrical loads 218.

[0024] Pre-charging can be initiated by closing the positive-side pre-charging switch 204 and the feedback contactor 208. After pre-charging is complete, the main contactor 206 can be closed and the positive-side pre-charging switch 204 opened. Pre-charging can also be initiated by closing the main contactor 206 and the feedback-side pre-charging switch 212. After pre-charging is complete, the feedback contactor 208 can be closed and the feedback-side pre-charging switch 212 opened. After pre-charging is complete, the main contactor 206 and the feedback contactor 208 can be held in the closed position.

[0025] The contactor module 242 can include a contactor controller 220, which is designed to operate and sequence the contactors and switches. Although the contactor controller 220 is shown as part of the contactor module 242, it can be part of an external controller (e.g., system controller 148 or a traction battery controller). The contactor controller 220 can include a processor and memory, including volatile and non-volatile memory. The contactor controller 220 can include hardware to provide an interface to the contactors and switches. For example, the contactor controller 220 can include outputs designed to supply voltage and current to contactor coils to energize the contactors.

[0026] The contactor module 242 can include a battery-side voltage sensing device 214, which is coupled between the terminals of the traction battery 124. The contactor module 242 can include a load-side voltage sensing device 216, which is coupled between the terminals of the high-voltage load bus 152. For example, the voltage sensing devices can be a resistor network that scales the voltage levels to be compatible with the contactor controller 220. The voltage sensing devices 214 and 216 can also include circuits for filtering the voltage signals and isolating the contactor controller 220 from high voltages. The contactor controller 220 can receive a signal from the battery-side voltage sensing device 214 indicating the traction battery voltage. The contactor controller 220 can receive a signal from the load-side voltage sensing device 216 indicating the high-voltage load bus voltage.

[0027] Pre-charging can be completed when the difference between the traction battery voltage and the high-voltage load bus voltage falls below a predetermined threshold. Pre-charging can also be completed when the high-voltage load bus voltage is within a predetermined range of the traction battery voltage (e.g., within 20 V). Finally, pre-charging can be completed after a predetermined time interval has elapsed since the initiation of pre-charging. The contactor control 220 can monitor the voltages and time intervals to determine that pre-charging is complete.

[0028] The configurations described herein are robust against conditions in which either the main contactor 206 or the feedback contactor 208 is welded in a closed position. Even if either the main contactor 206 or the feedback contactor 208 is permanently closed, it is still possible to perform the pre-charging operation via the other contactor. For example, if the main contactor 206 is welded in the closed position, the pre-charging operation can be performed via the pre-charging circuit (e.g., the feedback-side pre-charging resistor 210 and the feedback-side pre-charging switch 212) through the feedback contactor 208. Consequently, the traction battery 124 can be connected to the electrical loads 218 without excessive currents flowing through the feedback contactor 208.

[0029] Fig. Figure 3 represents a configuration of a high-voltage power distribution system 300 for a vehicle, which includes a variety of contactors. The contactor module 342 can include a main contactor 306, which is designed to selectively electrically couple a positive terminal 222 of the traction battery 124 to a positive-side conductor 152A of the high-voltage load bus 152. The contactor module 342 can include a feedback contactor 308, which is designed to selectively electrically couple a traction battery feedback terminal 224 (return terminal of the traction battery 124) to a feedback-side conductor 152B of the high-voltage load bus 152. The contactor module 342 can include a pre-charge resistor 302, which can be selectively coupled via either the main contactor 306 or the feedback contactor 308.

[0030] A first switch 304 can be connected between the positive terminal 222 of the traction battery 124 and a first terminal of the pre-charge resistor 302. The first switch 304 can be an electromagnetic contactor. A first diode 322 can be connected between the positive-side conductor 152A of the high-voltage load bus 152 and a second terminal of the pre-charge resistor 302. The first diode 322 can be arranged such that current flow from the pre-charge resistor 302 to the positive-side conductor 152A is permitted.

[0031] A second switch 310 can be connected between the traction battery return terminal 224 and the first terminal of the pre-charge resistor 302. The second switch 310 can be an electromagnetic contactor. A second diode 324 can be connected between the return-side conductor 152B of the high-voltage load bus and the second terminal of the pre-charge resistor 302. The second diode 324 can be arranged in the circuit such that current flow from the return-side conductor 152B to the pre-charge resistor 302 is permitted.

[0032] The contactor module 342 can include a contactor controller 320, which is designed to operate and sequence the contactors and switches. Although the contactor controller 320 is shown as part of the contactor module 342, it can be part of an external controller (e.g., system controller 148 or a traction battery controller). The contactor controller 320 can include a processor along with volatile and non-volatile memory. The contactor controller 320 can include hardware to provide an interface to the contactors and switches. For example, the contactor controller 320 can include outputs designed to supply voltage and current to contactor coils to energize the contactors.

[0033] The contactor module 342 can include a battery-side voltage sensing device 314, which is coupled between the terminals of the traction battery 124. The contactor module 342 can include a load-side voltage sensing device 316, which is coupled between the terminals of the high-voltage load bus 152. For example, the voltage sensing devices can be a resistor network that scales the voltage levels to be compatible with the contactor controller 320. The voltage sensing devices 314 and 316 can also include circuits for filtering the voltage signals and isolating the contactor controller 320 from high voltages.

[0034] The contactor control 320 can receive a signal from the battery-side voltage sensing device 314 indicating the traction battery voltage. The contactor control 320 can receive a signal from the load-side voltage sensing device 316 indicating the high-voltage load bus voltage.

[0035] Pre-charging can be carried out by operating the first switch 304 and the second switch 310. Depending on the state of the first switch 304 and the second switch 310, the pre-charging resistor 302 can be coupled either via the main contactor 306 or the feedback contactor 308. For example, to pre-charge, when the main contactor 306 is open, the feedback contactor 308 is closed and the first switch 304 is closed to couple the pre-charging resistor 302 via the main contactor 306. Current from the traction battery 124 flows through the first switch 304, the pre-charge resistor 302, the first diode 322, the electrical load 218, and the feedback contactor 308. To pre-charge, when the feedback contactor 308 is open, the main contactor 306 is closed and the second switch 310 is closed to couple the pre-charge resistor 302 via the feedback contactor 308.Current from the traction battery 124 flows through the main contactor 306, the electrical load 218, the second diode 324, the pre-charge resistor 302 and the second switch 310.

[0036] Fig. Figure 4 represents a configuration of a high-voltage power distribution system 400 for a vehicle, which includes a variety of contactors. The contactor module 442 can include a main contactor 406, which is designed to selectively electrically couple a positive terminal 222 of the traction battery 124 to a positive-side conductor 152A of the high-voltage load bus 152. The contactor module 442 can include a feedback contactor 408, which is designed to selectively electrically couple a traction battery feedback terminal 224 (return terminal of the traction battery 124) to a feedback-side conductor 152B of the high-voltage load bus 152. The contactor module 442 can include a pre-charge resistor 402, which can be selectively coupled via either the main contactor 406 or the feedback contactor 408.

[0037] A first solid-state switch 404 can be connected between the positive terminal 222 of the traction battery 124 and a first terminal of the pre-charge resistor 402. The first solid-state switch 404 can be a p-channel metal-oxide-semiconductor field-effect transistor (MOSFET). A first diode 422 can be connected between the positive-side conductor 152A of the high-voltage load bus 152 and a second terminal of the pre-charge resistor 402. The first diode 422 can be arranged such that current flow from the pre-charge resistor 402 to the positive-side conductor 152A is permitted.

[0038] A second solid-state switch 410 can be connected between the traction battery return terminal 224 and the first terminal of the pre-charge resistor 402. The second solid-state switch 410 can be an n-channel MOSFET. A second diode 424 can be connected between the return-side conductor 152B of the high-voltage load bus and the second terminal of the pre-charge resistor 402. The second diode 424 can be arranged in the circuit such that current flow from the return-side conductor 152B to the pre-charge resistor 402 is permitted. The MOSFETs can include an intrinsic diode, which is not shown.

[0039] The contactor module 442 can include a contactor controller 420, which is designed to operate and sequence the contactors and solid-state switches. Although the contactor controller 420 is shown as part of the contactor module 442, it can be part of an external controller (e.g., system controller 148 or a traction battery controller). The contactor controller 420 can include a processor along with volatile and non-volatile memory. The contactor controller 420 can include hardware to provide an interface to the contactors and switches. For example, the contactor controller 420 can include outputs designed to supply voltage and current to contactor coils to energize the contactors. The contactor controller 420 can include circuitry to provide a gate drive signal to the solid-state switches (404, 410).

[0040] The contactor module 442 can include a battery-side voltage sensing device 414, which is coupled between the terminals of the traction battery 124. The contactor module 442 can include a load-side voltage sensing device 416, which is coupled between the terminals of the high-voltage load bus 152. For example, the voltage sensing devices can be a resistor network that scales the voltage levels to be compatible with the contactor controller 420. The voltage sensing devices 414 and 416 can also include circuits for filtering the voltage signals and isolating the contactor controller 420 from high voltages. The contactor controller 420 can receive a signal from the battery-side voltage sensing device 414 indicating the traction battery voltage. The contactor controller 420 can receive a signal from the load-side voltage sensing device 416 indicating the high-voltage load bus voltage.

[0041] Pre-charging can be carried out by operating the first solid-state switch 404 and the second solid-state switch 410. Depending on the state of the first solid-state switch 404 and the second solid-state switch 410, the pre-charging resistor 402 can be coupled either via the main contactor 406 or the feedback contactor 408. For example, to pre-charge, when the main contactor 406 is open, the feedback contactor 408 is closed and the first solid-state switch 404 is operated to couple the pre-charging resistor 402 via the main contactor 406. Current from the traction battery 124 flows through the first solid-state switch 404, the pre-charge resistor 402, the first diode 422, the electrical load 218, and the feedback contactor 408. To pre-charge, when the feedback contactor 408 is open, the main contactor 406 is closed and the second solid-state switch 410 is operated to couple the pre-charge resistor 402 via the feedback contactor 408.Current from the traction battery 124 flows through the main contactor 406, the electrical load 218, the second diode 424, the pre-charge resistor 402 and the second solid-state switch 410.

[0042] Certain aspects are discussed in relation to the in Fig. The configuration shown in Figure 4 is described. Furthermore, the features and functions described for each of the configurations apply to all configurations and are not necessarily repeated. The concepts to be described are also applicable to the other configurations described herein. It should be noted that the configurations described in the figures provide the ability to couple the pre-charge resistor via either the main contactor or the feedback contactor. The contactor control 420 can be programmed to detect a contactor that is welded in the closed position. For example, the contactor control 420 can be configured to detect that the main contactor 406 is closed, even though it is commanded to be open. Likewise, the contactor control 420 can be configured to detect that the feedback contactor 408 is closed, even though it is commanded to be open.Several techniques are available for detecting a welded contactor. The operation of contactor module 424 as described is not limited to the specific scheme used to detect a welded contactor.

[0043] A welded-on contactor can be identified by monitoring the outputs of the battery-side voltage sensing device 414 and the load-side voltage sensing device 416. For example, the contactor controller 420 can receive or generate a request to open the contactors to isolate the traction battery 124 from the high-voltage load bus 152. During vehicle operation, both the main contactor 406 and the feedback contactor 408 are closed. In response to a request to open the contactors, the controller 420 can command the main contactor 406 to open. After the main contactor 406 has been commanded to open, the traction battery voltage can be compared to the load-side voltage. The comparison can be performed a predetermined delay time after the main contactor 406 has been commanded to open, to allow the load-side voltage to dissipate.If the difference between the traction battery voltage and the load-side voltage is greater than a predetermined amount, then the main contactor 406 is likely to be open as commanded. If the load-side voltage is within a predetermined range of the traction battery voltage, then the main contactor 406 is likely to be closed. In this way, a main contactor 406 that is welded shut can be identified. For example, if the load-side voltage has not dropped (i.e., is approximately equal to the traction battery voltage), then the main contactor 406 is likely to be closed.

[0044] In response to a request to open the contactors, the contactor controller 420 can only command the feedback contactor 408 to open. After the feedback contactor 408 has been commanded to open, the traction battery voltage can be compared to the load-side voltage. This comparison can be performed after a predetermined delay following the feedback contactor 408's opening command, to allow the load-side voltage to drop. If the difference between the traction battery voltage and the load-side voltage is greater than a predetermined amount, then the feedback contactor 408 is likely open as commanded. If the load-side voltage is within a predetermined range of the traction battery voltage, then the feedback contactor 408 is likely still closed. In this way, a welded-on feedback contactor 408 can be identified.Other techniques may involve circuits designed to provide resistance measurement across the main contactor 406 and the feedback contactor 408. For example, a high resistance reading may indicate an open contactor, while a low resistance reading may indicate a closed contactor.

[0045] The contactor controller 420 can monitor the rise time of the load-side voltage during a pre-charging operation. For example, the pre-charging resistor 402 can be coupled via the main contactor 406 during a pre-charging operation, in addition to closing the feedback contactor 408. A rate of change of the load-side voltage greater than a predetermined rise time can indicate that the main contactor 406 is short-circuited. An indication that the main contactor 406 and / or the feedback contactor 408 is short-circuited when commanded to be open can be stored in non-volatile memory for later use. In other configurations, a test for short-circuited contactors can be performed immediately before the pre-charging operation.

[0046] In the event that the main contactor 406 or the feedback contactor 408 is short-circuited, the pre-charging operation can be modified. In response to a pre-charging request, the pre-charging resistor 402 can be coupled via the contactor that is not short-circuited. For example, if the main contactor 406 is short-circuited, the pre-charging resistor 402 can be coupled via the feedback contactor 408 to perform the pre-charging. When the pre-charging resistor 402 is coupled in the circuit, the current flow from the traction battery 124 is limited. The pre-charging operation can then be terminated via the normal pre-charging termination conditions. Once the pre-charging is complete, the feedback contactor 408 can be closed, and the pre-charging resistor 402 can be disconnected from the circuit.

[0047] When the feedback contactor 408 is short-circuited, the pre-charge resistor 402 can be coupled via the main contactor 406 to perform the pre-charging. When the pre-charge resistor 402 is coupled in the circuit, the current flow from the traction battery 124 is limited. The pre-charging operation can then be terminated via the normal pre-charge termination conditions. When the pre-charging is complete, the main contactor 406 can be closed and the pre-charge resistor 402 can be disconnected from the circuit.

[0048] By designing the 442 contactor module to have multiple pre-charging paths, pre-charging can be performed even if one of the contactors is short-circuited. This prevents potential arcing in the contactor that is still operating normally and allows the vehicle to function normally. A diagnostic indicator can be provided to show the short-circuited contactor status. For example, a diagnostic message or light can be displayed to inform the driver that the contactor module will require servicing soon.

[0049] Fig.Figure 5 represents a flowchart 500 of a possible sequence of operations that can be performed by a high-voltage bus pre-charging system, which includes the contactor control 420 for controlling the operation of the contactors and switches. Operation 502 allows a check to be performed to determine whether the contactors should be closed. For example, a request to connect the traction battery 124 to the high-voltage load bus can be monitored. If no conditions exist for closing the contactors, operation 502 can be repeated. If conditions exist for closing the contactors, operation 504 can be performed.

[0050] In operation 504, data relating to short-circuited contactors can be retrieved. A contactor is short-circuited if it is closed when commanded to be open. For example, previously performed diagnostic tests can store short-circuited contactor information in non-volatile memory. In operation 506, a preload path can be selected based on the short-circuited contactor data. The preload path can be defined as the contactor to be closed and the contactor through which the preload resistor 402 is to be coupled. The preload resistor 402 can be coupled through the contactor (e.g., main contactor 406 or feedback contactor 408) that is not short-circuited.

[0051] Furthermore, operation 506 can select the pre-charging path to minimize wear across the contactors. Even after pre-charging, the contactors may be exposed to current flowing through them during closing. The contactor control 420 can be programmed to alternate between coupling the pre-charging resistor 402 via the main contactor 406 and the feedback contactor 408. The contactor control 420 can determine the pre-charging path for the most recent pre-charging cycle and alternate the pre-charging path for each pre-charging request. For example, in response to a pre-charging request that follows an immediately preceding pre-charging request that resulted in the pre-charging resistor 402 being coupled via the main contactor 406, the pre-charging resistor 402 can be coupled via the feedback contactor 408.Similarly, the pre-charge resistor 402 can be coupled via the main contactor 406 in response to the pre-charge request that follows the immediately preceding pre-charge request, which caused the pre-charge resistor 402 to be coupled via the feedback contactor 408. The immediately preceding pre-charge request refers to the most recent pre-charge request. The immediately preceding pre-charge request may have occurred in a previous firing cycle. The contactor control 420 can store information for each pre-charge cycle in non-volatile memory, so that the information is available during subsequent operating cycles. In this way, any arc formation is shared between the contactors.

[0052] In operation 508, the pre-charging operation can be performed. The pre-charging operation can include closing the selected contactor and operating the switches to couple the pre-charging resistor 402 in the selected path. The pre-charging operation can also include monitoring the voltage and current during the pre-charging process.

[0053] In operation 510, a check can be performed to determine whether the pre-charge is complete. For example, the pre-charge may be considered complete if the load-side voltage is within a predetermined range of the traction battery voltage. The pre-charge operation may also be considered complete after a predetermined time interval. This predetermined time interval may be selected to prevent overheating of the pre-charge resistor. If the pre-charge is not complete, operations 508 and 510 can be repeated during the predetermined time interval. If the pre-charge is complete, operation 512 can be performed.

[0054] In operation 512, both the main contactor 406 and the feedback contactor 408 can be commanded to be closed. Furthermore, the pre-charge resistor 402 can be decoupled from the circuit by operating the switches, so that the pre-charge resistor 402 is no longer in the current path.

[0055] In operation 514, a check can be performed for a request to open the contactors. A request to open the contactors can result from a command to switch off the ignition. If there is no request to open the contactors, then operation 514 can be repeated. If there is a request to open the contactors, then operation 516 can be performed to open the contactors. Before opening the contactors, electrical loads 218 can be commanded to reduce current consumption so that the main contactor 406 and the feedback contactor 408 open with minimal current flow. Operation 518 can be performed to detect and identify a short-circuited contactor. This can be done as part of the contactor opening process. For example, the contactor opening process can be sequenced to detect a short-circuited contactor. The stored data can include an identification of the short-circuited contactor.In process 520, short-circuited contactor data can be stored in non-volatile memory for later retrieval. The execution can then return to process 502.

[0056] The configuration described herein provides options for precharging the power system in the event of a short-circuited contactor. The ability to prechar the system via both contactors reduces the possibility of arcing and welding to the correctly functioning contactor. Furthermore, vehicle operation can be maintained in the event of a faulty contactor, preventing the driver from being stranded.

[0057] The processes, methods, or algorithms disclosed herein may be inputted to or implemented by a processing device, controller, or computer, which may include any existing programmable electronic control unit or dedicated electronic control unit. Likewise, the processes, methods, or algorithms may be stored as data and instructions that can be executed by a controller or computer in many forms, including, but not limited to, information permanently stored in non-writable storage media such as ROM devices, and information modifiably stored in writable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The processes, methods, and algorithms may also be implemented in a software-executable object.Alternatively, the processes, procedures or algorithms can be implemented wholly or partially using suitable hardware components, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software and firmware components.

Claims

[1] Vehicle (112), comprising: a pre-charging circuit designed to selectively couple a resistor (202, 302, 402) via either a first (206, 306, 406) or a second contactor (208, 308, 408) designed to selectively couple terminals of a battery (124) to a load bus (152); and a controller (220, 320, 420) programmed to couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in response to a pre-charge request in a case where the first contactor (206, 306, 406) is closed when commanded to open and the second contactor (208, 308, 408) is open, in order to pre-charge the load bus (152), characterized by , that The controller (220, 320, 420) is further programmed to, in response to the pre-charge request in a case where both the first contactor (206, 306, 406) and the second contactor (208, 308, 408) are open and following an immediately preceding pre-charge request that resulted in the resistor (202, 302, 402) being coupled via the first contactor (206, 306, 406), couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in order to pre-charge the load bus (152). [2] Vehicle (112) according to claim 1, wherein the control unit (220, 320, 420) is further programmed to couple the resistor (202, 302, 402) via the first contactor (206, 306, 406) in response to the pre-charging request in a case where the first contactor (206, 306, 406) is open and the second contactor (208, 308, 408) is closed, when it is commanded to open, in order to pre-charge the load bus (152). [3] Vehicle (112) according to claim 1, wherein the controller (220, 320, 420) is further programmed to couple the resistor (202, 302, 402) via the first contactor (206, 306, 408) in response to the pre-charge request in a case where both the first contactor (206, 306, 406) and the second contactor (208, 308, 408) are open and following an immediately preceding pre-charge request that caused the resistor (202, 302, 402) to be coupled via the second contactor (208, 308, 408) in order to pre-charge the load bus (152). [4] Procedure comprising the following: Coupling a resistor (202, 302, 402) via a first contactor (206, 306, 406) coupled between the negative terminals of a battery (124) and a load bus (152) in response to a pre-charge request, and to the fact that a second contactor (208, 308, 408) coupled between the positive terminals of the battery (124) and the load bus (152) is short-circuited when it is commanded to open; and Coupling of the resistor (202, 302, 402) via the second contactor (208, 308, 408) in response to the preload request and the fact that the second contactor (208, 308, 408) is open, characterized by , that The coupling of the resistor (202, 302, 402) via the second contactor (208, 308, 408) also takes place as a reaction to the preload request, which follows an immediately preceding preload request that resulted in the resistor (202, 302, 402) being coupled via the first contactor (206, 306, 406). [5] Method according to claim 4, further comprising coupling the resistor (202, 302, 402) via the second contactor (208, 308, 408) in response to the pre-loading request and to the fact that the first contactor (206, 306, 406) is short-circuited when it is commanded to open. [6] Method according to claim 4, further comprising coupling the resistor (202, 302, 402) via the first contactor (206, 306, 406) in response to the fact that both the first (206, 306, 406) and the second contactor (208, 308, 408) are open and the preload request follows an immediately preceding preload request which caused the resistor (202, 302, 402) to be coupled via the second contactor (208, 308, 408). [7] Vehicle (112), comprising: a pre-charging circuit designed to selectively couple a resistor (202, 302, 402) via either a first (206, 306, 406) or a second contactor (208, 308, 408) designed to selectively couple terminals of a battery (124) to a load bus (152); and a controller (220, 320, 420) programmed to, in response to a pre-charge request following an immediately preceding pre-charge request that resulted in the resistor (202, 302, 402) being coupled via the first contactor (206, 306, 406), couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in order to pre-charge the load bus (152). [8] Vehicle (112) according to claim 7, wherein the control unit (220, 320, 420) is further programmed to couple the resistor (202, 302, 402) via the first contactor (206, 306, 406) in response to the pre-charge request following the immediately preceding pre-charge request that caused the resistor (202, 302, 402) to be coupled via the first contactor (206, 306, 406) and to the fact that the second contactor (208, 308, 408) is closed when it is commanded to open. [9] Vehicle (112) according to claim 7, wherein the control unit (220, 320, 420) is further programmed to couple the resistor (202, 302, 402) via the first contactor (206, 306, 406) in response to the pre-charge request following the immediately preceding pre-charge request which caused the resistor (202, 302, 402) to be coupled via the second contactor (208, 308, 408) in order to pre-charge the load bus (152). [10] Vehicle (112) according to claim 7, wherein the control unit (220, 320, 420) is further programmed to couple the resistor (202, 302, 402) via the second contactor (208, 308, 408) in response to the pre-charge request following the immediately preceding pre-charge request that caused the resistor (202, 302, 402) to be coupled via the second contactor (208, 308, 408), and to the first contactor (206, 306, 406) being closed when it is commanded to open. [11] Vehicle (112) according to claim 1 or claim 7, wherein the pre-charging circuit comprises a first switching device (204) designed to selectively couple the resistance (202, 302, 402) between a positive terminal (222) of the battery (124) and a positive terminal (152A) of the load bus (152) and a second switching device (212) designed to selectively couple the resistance (202, 302, 402) between a negative terminal of the battery (124) and a negative terminal of the load bus (152). [12] Vehicle (112) according to claim 1 or claim 7, wherein the first switching device (204) is a p-channel metal oxide semiconductor field effect transistor (MOSFET) and the second switching device (212) is an n-channel MOSFET. [13] Vehicle (112) according to claim 1 or claim 7, wherein the pre-charging circuit further comprises a first diode (322, 422) coupled between the resistor (202, 302, 402) and the positive terminal (152A) of the load bus (152) and designed to conduct current when the first switching device (204) selectively couples the resistor (202, 302, 402), and a second diode (324, 424) coupled between the resistor (202, 302, 402) and the negative terminal of the load bus (152) and designed to conduct current when the second switching device (212) selectively couples the resistor (202, 302, 402).

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