A method and system for controlling the on-off of the HV side output loop of an on-board charger

Abstract

The application discloses a kind of methods and systems for controlling the on-off of vehicle charger HV side output loop, the method includes S1, S2, S3 and S4.The application realizes that vehicle charger OBCHV side needs to ensure that there is no power (no voltage / no current) to the outside in the state of charging completion and plug-in by adopting the mode of adding relay and its two side voltage detection loop in the all-in-one controller, and other high voltage circuits cannot have high voltage, to ensure the safety of the whole vehicle high voltage system.The scheme does not change the original MCU, DCDC&OBC module hardware circuit, and the scheme is simple, with small amount of changes, and the control strategy can be achieved by slight adjustment.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle technology, specifically a method and system for controlling the on / off state of the output circuit on the HV side of an on-board charger. Background Technology

[0002] Currently, the power systems, power distribution systems, and air conditioning systems of new energy vehicles mostly use high-voltage electricity. This places higher demands on the safety of the vehicle's high-voltage circuits. Therefore, whenever possible, the number of high-voltage components carrying high-voltage electricity should be minimized.

[0003] The all-in-one electric drive system integrates a motor, motor controller, reducer, on-board charger (OBC), high-to-low voltage converter (DCDC), and high-voltage distribution unit (PDU) – including copper busbars, fuses, fast-charging relays, PTC power distribution and relays, and AC. When designing the high-voltage topology, it is crucial to consider the energizing conditions of each high-voltage component under various operating conditions to ensure the safety of the high-voltage system. For example, when the on-board charger has finished charging the battery pack and is plugged in, the OBC HV side must ensure no power output (no voltage / no current) to the outside, and no high-voltage current in other high-voltage circuits to ensure the safety of the entire vehicle's high-voltage system. Simultaneously, the DCDC module must have the capability to output its rated power to ensure that after the vehicle is fully charged, the DCDC high-voltage input comes from the OBC output and the external charging station. The operation of the vehicle's low-voltage electrical equipment does not consume power from the 12V battery or the battery pack.

[0004] To achieve this function, a new method and system for controlling the HV side output circuit of the on-board charger has been invented: namely, a method and system for controlling the on / off switching of the high-voltage DC output circuit of the on-board charger in the multi-in-one electric drive assembly. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for controlling the on / off switching of the HV-side output circuit of an on-board charger, which has the advantages of charging safety, high efficiency, and low cost.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method and system for controlling the on / off state of the output circuit on the HV side of an on-board charger, wherein the circuit system is composed as follows:

[0007] The circuit system is as follows:

[0008] The positive terminal of the DC high voltage output of the DCDC & OBC is connected to the relay, and then to the positive terminal of the battery pack input.

[0009] The negative terminal of the DC high voltage output of the DCDC & OBC is directly connected to the negative terminal of the battery pack input via a wire / copper busbar.

[0010] The MCU module directly controls the relay via a low-voltage wire, and at the same time, two low-voltage wires collect the voltage on both sides of the relay to detect and determine if the relay is stuck.

[0011] The control method is as follows:

[0012] S1. When the slow charging gun is plugged in for charging, the MCU or DC-DC & OBC module receives relevant instructions to control the relay to close and detects the voltage on both sides to prevent the relay from sticking together. The OBC charges the battery pack.

[0013] S2. When charging is complete and the charging gun is plugged in, the MCU or DCDC & OBC module receives a relevant instruction to control the relay to disconnect. The OBC and DCDC modules do not stop working, ensuring that the DCDC can output the rated power.

[0014] S3. When charging is complete and the charging gun is not plugged in, the MCU or DC-DC & OBC module receives the relevant instruction to control the relay to disconnect.

[0015] S4. When the vehicle is normally connected to high voltage, the MCU or DC-DC & OBC module receives relevant instructions (controlling the relay to close, and controlling the relay to open when the power is off).

[0016] Preferably, the instructions received by the MCU or DC-DC & OBC module come from the VCU or BMS.

[0017] Preferably, the VCU and BMS commands include, but are not limited to, motor and battery status, and the acquisition of accelerator pedal signals, brake pedal signals, actuator and sensor signals.

[0018] Preferably, the closing and opening of the relay can also be controlled by VCU or BMS.

[0019] Preferably, the slow charging pile is fixedly installed outside the electric vehicle and connected to the AC power grid, and the power of the slow charging pile is 3.3-7KW.

[0020] On the other hand, the present invention also provides a system for controlling the on / off switching of the HV side output circuit of an on-board charger, characterized in that the system comprises:

[0021] The first module is used to control the relay to close and detect the voltage on both sides to prevent the relay from sticking when the slow charging gun is plugged in, and the OBC charges the battery pack.

[0022] The second module is used to control the relay to disconnect when the charging is complete and the charging gun is plugged in, so that the OBC and DC-DC modules do not stop working and the DC-DC can output the rated power.

[0023] The third module is used when charging is complete and the charging gun is not plugged in, and the MCU or DC-DC & OBC module receives relevant instructions to control the relay to disconnect.

[0024] The third module is used when the vehicle is normally connected to high voltage, the MCU or DC-DC & OBC module receives relevant instructions to control the relay to close, and also controls the relay to open when the power is off.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This proposal achieves the following by adding a relay and its two sides' voltage detection circuits within a multi-functional controller: When charging is complete and the charging gun is plugged in, the on-board charger (OBCHV) must output no power (no voltage / no current) to the outside, and other high-voltage circuits must not have high voltage, ensuring the safety of the entire vehicle's high-voltage system. Simultaneously, the DC-DC module has the capability to output its rated power. This solution achieves this without altering the original hardware circuitry of the MCU, DC-DC, and OBC modules; the solution is simple, requires minimal modifications, and can be implemented with slight adjustments to the control strategy.

[0027] This proposal uses a relay and its two-sided voltage detection circuits to achieve this function, which has the advantages of small size, low cost, mature technology, easy implementation, and short development cycle. Attached Figure Description

[0028] Figure 1 This is a circuit diagram of the system of the present invention; Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a technical solution: a method for controlling the on / off state of the output circuit on the HV side of an on-board charger, wherein the circuit system is as follows:

[0031] The circuit system is as follows:

[0032] The positive terminal of the DC high voltage output of the DCDC & OBC is connected to the relay, and then to the positive terminal of the battery pack input.

[0033] The negative terminal of the DC high voltage output of the DCDC & OBC is directly connected to the negative terminal of the battery pack input via a wire / copper busbar.

[0034] The MCU module directly controls the relay via a low-voltage wire, and at the same time, two low-voltage wires collect the voltage on both sides of the relay to detect and determine if the relay is stuck.

[0035] The control method is as follows:

[0036] S1. When the slow charging gun is plugged in for charging, the MCU or DC-DC & OBC module receives relevant instructions to control the relay to close and detects the voltage on both sides to prevent the relay from sticking together. The OBC charges the battery pack.

[0037] S2. When charging is complete and the charging gun is plugged in, the MCU or DCDC & OBC module receives a relevant instruction to control the relay to disconnect. The OBC and DCDC modules do not stop working, ensuring that the DCDC can output the rated power.

[0038] S3. When charging is complete and the charging gun is not plugged in, the MCU or DC-DC & OBC module receives the relevant instruction to control the relay to disconnect.

[0039] S4. When the vehicle is normally connected to high voltage, the MCU or DC-DC & OBC module receives relevant instructions (controlling the relay to close, and controlling the relay to open when the power is off).

[0040] Currently, after OBC charging is complete, the vehicle control unit (VCU) or battery management system (BMS) sends a shutdown command to the OBC, causing it to shut down. This ensures the high-voltage circuit of the vehicle is not carrying high voltage, guaranteeing its safety. However, this method cannot utilize the electricity converted from the charging pile's power supply to provide 12V to the low-voltage circuit via DC-DC converter. Providing power to the vehicle's 12V low-voltage system would require draining the battery pack, which is unacceptable to OEMs and end customers.

[0041] To address the aforementioned issues, this solution requires modules such as MCU, VCU, OBC, and BMS to participate in the control of the OBC output circuit's on / off state. This necessitates the addition of new control strategies and corresponding devices and circuits to ensure intelligent control and maximize the safe and stable operation of the overall electrical control system. The power supply module can also operate safely as needed.

[0042] The instructions received by the MCU or DC-DC & OBC module come from the VCU or BMS.

[0043] The VCU and BMS commands include, but are not limited to, motor and battery status, and the acquisition of accelerator pedal signals, brake pedal signals, actuator and sensor signals.

[0044] The closing and opening of the relay can also be controlled by VCU or BMS.

[0045] The slow charging pile is fixedly installed outside the electric vehicle and connected to the AC power grid. The slow charging pile has a power output of 3.3-7KW. In practice, electric vehicle charging devices are generally divided into fast charging (DC charging piles) and slow charging (AC charging piles), each with its own advantages. Fast charging, as the name suggests, has high charging efficiency. Considering common fast charging devices on the market, a vehicle can be fully charged in approximately 2-4 hours, while slow charging requires 8 hours or more. Theoretically, fast charging is more efficient. However, this solution prioritizes slow charging piles. Therefore, a simple analysis of the current market situation will be provided below:

[0046] A. The overall power of the on-board charger of a typical pure electric vehicle is not large, so slow charging can meet its normal operation.

[0047] B. Meanwhile, the development of pure electric new energy vehicles is relatively late, and the development of various supporting measures is relatively slow. Slow charging piles have low overall manufacturing and installation costs and are easy to manage. Moreover, the overall technology appeared early and is relatively mature.

[0048] C. Currently, slow charging pile technology is well-developed and meets a series of national environmental protection policies and measures, with low risk of iteration in the short term;

[0049] D. Currently, slow charging stations have comprehensive current protection measures, and their compatibility and stability with car battery charging processes are also better.

[0050] like Figure 1 As shown, a relay and its voltage detection circuits on both sides are added to the positive output of OBCHV. This relay can be controlled by the motor controller MCU, the DC-DC & OBC module, or even the VCU and BMS. The control logic is the same; only the control module differs. The diagram shows MCU control, and its working principle is as follows:

[0051] When the slow charging gun is plugged in for charging, the MCU or DC-DC & OBC module receives relevant instructions (VCU or BMS) to control the relay to close and detect the voltage on both sides to prevent the relay from sticking (it can also be directly controlled by VCU or BMS), and the OBC charges the battery pack.

[0052] When charging is complete and the charging gun is plugged in, the MCU or DCDC & OBC module receives the relevant instructions (VCU or BMS) to control the relay to disconnect (or it can be directly controlled by VCU or BMS). The OBC and DCDC modules do not stop working, ensuring that the DCDC can output the rated power.

[0053] Once charging is complete and the charging gun is not plugged in, the MCU or DC-DC & OBC module receives the relevant instruction (VCU or BMS) to control the relay to disconnect (it can also be directly controlled by the VCU or BMS).

[0054] When the vehicle is normally powered on with high voltage, the MCU or DC-DC & OBC module receives relevant instructions (VCU or BMS) to control the relay to close (or can be directly controlled by VCU or BMS). When the power is off, it also controls the relay to open.

[0055] On the other hand, the present invention also provides a system for controlling the on / off switching of the HV-side output circuit of an on-board charger, the system comprising:

[0056] The first module is used to control the relay to close and detect the voltage on both sides to prevent the relay from sticking when the slow charging gun is plugged in, and the OBC charges the battery pack.

[0057] The second module is used to control the relay to disconnect when the charging is complete and the charging gun is plugged in, so that the OBC and DC-DC modules do not stop working and the DC-DC can output the rated power.

[0058] The third module is used when charging is complete and the charging gun is not plugged in, and the MCU or DC-DC & OBC module receives relevant instructions to control the relay to disconnect.

[0059] The third module is used when the vehicle is normally connected to high voltage, the MCU or DC-DC & OBC module receives relevant instructions to control the relay to close, and also controls the relay to open when the power is off.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for controlling the on-off of the HV side output loop of an on-board charger, characterized in that: the system comprises a DCDC&OBC module, a relay, a battery pack and an MCU; the DCDC&OBC module comprises an OBC topology and a DCDC topology; the DCDC topology is connected in parallel to the output of the OBC topology; the relay is arranged on the HV output positive wire of the OBC topology; the batteries in the battery pack are connected to the positive and negative output terminals of the OBC topology through the main positive relay and the main negative relay; the MCU collects the voltages on both sides of the relay through two low-voltage wires and controls the relay to close or open.

2. A method for controlling the on-off of the HV side output loop of the on-board charger, applied to the system of claim 1, characterized in that, The control method is as follows: S1, when the slow charging gun is plugged in for charging, the MCU or the DCDC&OBC module receives relevant instructions to control the relay to close and detect the voltages on both sides to prevent the relay from sticking, and the OBC charges the battery pack; S2, when the charging is completed and the gun is plugged in, the MCU or the DCDC&OBC module receives relevant instructions to control the relay to open, and the OBC and DCDC modules do not stop working to ensure that the DCDC can output rated power; S3, when the charging is completed and the gun is not plugged in, the MCU or the DCDC&OBC module receives relevant instructions to control the relay to open; S4, when the vehicle is normally powered with high voltage, the MCU or the DCDC&OBC module receives relevant instructions to control the relay to close, and when the power is off, the relay is also controlled to open.

3. The method of claim 2, characterized in that: the DCDC&OBC direct current high voltage output positive terminal is connected to the relay, and then connected to the input positive terminal of the battery pack.

4. The method of claim 2, characterized in that: the instructions received by the MCU or the DCDC&OBC module come from the VCU or the BMS.

5. The method of claim 4, characterized in that: the VCU and BMS instruction content includes but is not limited to motor and battery status, acceleration pedal signal, brake pedal signal, actuator and sensor signal.

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