A PDU relay adhesion detection circuit, detection method and vehicle operation control method

Abstract

The present invention relates to a PDU relay adhesion detection circuit, a detection method and a vehicle operation control method, including a battery box, a main relay, a capacitor, a pre-filling resistor, a first pre-filling relay and a second pre-filling relay, one end of the main relay is electrically connected to the positive terminal of the battery box, and the other end of the main relay is electrically connected to one end of the capacitor; the other end of the capacitor is electrically connected to the negative terminal of the battery box; one end of the pre-filling resistor is electrically connected to the common end of the battery box and the main relay, and the other end of the pre-filling resistor is electrically connected to one end of the first pre-filling relay; the other end of the first pre-filling relay is electrically connected to one end of the second pre-filling relay; the other end of the second pre-filling relay is electrically connected to the common end of the main relay and the capacitor. The present invention adopts two pre-filling relays to be pre-filled in series, and the possibility of two pre-filling relays adhering at the same time is low, which can protect the battery box.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a PDU relay adhesion detection circuit, a detection method, and an automobile operation control method. Background Art

[0002] The PDU, also known as the high-voltage distribution unit, is the power distribution center for an electric vehicle's high-voltage powertrain. It primarily provides high voltage through control relays. If a relay becomes stuck and there's no pre-charge circuit, the high current can damage system components like the battery and electronic controls. Therefore, a relay sticking detection, known as a power-on sticking test, is typically performed before sending a control signal to the pre-charge relay upon power-up. This fault is then reported to the vehicle. However, this detection method has several drawbacks: For example, if there's only one pre-charge relay on the pre-charge circuit and the relay becomes stuck, even if the battery box lacks a protective relay, the battery's high voltage will discharge to the subsequent loads through the pre-charge path, even if the vehicle loses power. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a PDU relay adhesion detection circuit, a detection method and a vehicle operation control method to overcome the deficiencies in the above-mentioned prior art.

[0004] The present invention solves the above technical problems with the following technical solutions: A PDU relay adhesion detection circuit includes a battery box, a main relay, a capacitor, a pre-charge resistor, a first pre-charge relay and a second pre-charge relay.

[0005] One end of the main relay is electrically connected to the positive terminal of the battery box, and the other end of the main relay is electrically connected to one end of the capacitor; the other end of the capacitor is electrically connected to the negative terminal of the battery box;

[0006] One end of the pre-charging resistor is electrically connected to the common end of the battery box and the main relay, and the other end of the pre-charging resistor is electrically connected to one end of the first pre-charging relay; the other end of the first pre-charging relay is electrically connected to one end of the second pre-charging relay; the other end of the second pre-charging relay is electrically connected to the common end of the main relay and the capacitor.

[0007] The beneficial effects of the present invention are: using two pre-charging relays in series for pre-charging, after power failure, the adhesion of one pre-charging relay will not affect the adhesion of the other pre-charging relay, and the possibility of the two pre-charging relays sticking at the same time is low, which can protect the battery box.

[0008] Furthermore: a first protection relay is connected in series between the common end of the pre-charging resistor and the main relay and the battery box.

[0009] Further: a second protection relay is connected in series between the capacitor and the battery box.

[0010] The beneficial effect of the above two-step solution is that by adding a dual-circuit protection relay, it can be ensured that after a power outage, there is no high voltage on the rear-end load, thus avoiding component damage.

[0011] Further: the common end of the battery box and the first protection relay is provided with a zero voltage detection point, the common end of the first protection relay, the pre-charging resistor and the main relay is provided with a first voltage detection point, the common end of the main relay, the second pre-charging relay and the capacitor is provided with a second voltage detection point, the common end of the capacitor and the second protection relay is provided with a third voltage detection point, the common end of the pre-charging resistor and the first pre-charging relay is provided with a fourth voltage detection point, and the common end of the first pre-charging relay and the second pre-charging relay is provided with a fifth voltage detection point.

[0012] A PDU relay adhesion detection method includes the following steps:

[0013] Step 1: After receiving the high voltage command, disconnect the main relay; and obtain the voltage values U0, U1, U2, U4, and U5 of the zero voltage detection point, the first voltage detection point, the second voltage detection point, the fourth voltage detection point, and the fifth voltage detection point relative to the third voltage detection point;

[0014] If U1=U2, and U5 equals 0, the main relay is stuck;

[0015] If U1=U2, and U5 is not equal to 0, then at least two of the first pre-charge relay, the second pre-charge relay, and the main relay are stuck;

[0016] If U1 is not equal to U2, and U5 is equal to 0, then the first pre-charge relay, the second pre-charge relay and the main relay are not stuck;

[0017] If U1 is not equal to U2, U5 is not equal to 0, and U5 = U1, then the first pre-charge relay is stuck;

[0018] If U1 is not equal to U2, U5 is not equal to 0, and U5 is not equal to U1, the second pre-charge relay is stuck;

[0019] In all cases other than the above, the first pre-charge relay, the second pre-charge relay and the main relay are not adhered;

[0020] Step 2: Disconnect the first protection relay and obtain the voltage value U1' of the first voltage detection point relative to the third voltage detection point at this time; if U1'=U1, the first protection relay is stuck; otherwise, the first protection relay is not stuck;

[0021] Step 3: Disconnect the second protection relay and obtain the voltage values U0' and U1" of the zero voltage detection point and the first voltage detection point relative to the third voltage detection point; if U0'=U1", the second protection relay is stuck, otherwise, the second protection relay is not stuck.

[0022] Further: 60ms-120ms after disconnecting the main relay in step 1, voltages U0, U1, U2, U4 and U5 are obtained.

[0023] Further: also includes step 4: storing the adhesion fault information of the first pre-filling relay, the second pre-filling relay, the main relay, the first protection relay and the second protection relay.

[0024] The beneficial effects of the above further solution are: the power-off adhesion detection is adopted, and the processing method is simple; and the adhesion fault information is stored, so that the fault can be reported when the low-voltage switch is powered on next time, and a prompt is given to replace the relay with adhesion.

[0025] A method for controlling vehicle operation includes the following steps:

[0026] Step a: Power on the low-voltage switch and read the stored adhesion fault information of the first pre-charge relay, the second pre-charge relay, the main relay, the first protection relay, and the second protection relay; if adhesion exists, disconnect the low-voltage switch, check and replace the relay with adhesion, and proceed to step b; otherwise, directly proceed to step c;

[0027] Step b: Power on the low-voltage switch and clear the stored adhesion fault information;

[0028] Step c: upon receiving the high voltage command, closing the second protection relay, the first protection relay, the first pre-charge relay, and the second pre-charge relay to pre-charge the load;

[0029] Step d: When the load voltage reaches 95%, close the main relay and disconnect the first pre-charge relay and the second pre-charge relay to power on the load with high voltage;

[0030] Step e: Carry out steps 1-3 in sequence.

[0031] Further: In the step c, the second protection relay, the first protection relay, the first pre-filling relay and the second pre-filling relay are closed in sequence, and the closing time interval between the first protection relay and the second protection relay is 40ms-70ms, and the closing time interval between the first pre-filling relay and the second pre-filling relay is 40ms-70ms.

[0032] Further: in the step d, the first pre-filling relay and the second pre-filling relay are sequentially disconnected after the main relay is closed for 60ms-120ms. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A circuit diagram of a PDU relay adhesion detection circuit according to the present invention;

[0034] Figure 2 The present invention is a control flow chart of a vehicle operation control method. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] The upper high-voltage command in the present invention refers to turning the car key from the OFF position to the ACC / ON position, and the lower high-voltage command refers to turning the car key from the ACC / ON position to the OFF position.

[0037] like Figure 1 and Figure 2 As shown, embodiment 1 of the present invention is a PDU relay adhesion detection circuit, comprising a battery box, a main relay K5, a capacitor, a pre-charge resistor R, a first pre-charge relay K3 and a second pre-charge relay K4,

[0038] One end of the main relay K5 is electrically connected to the positive terminal of the battery box, and the other end of the main relay K5 is electrically connected to one end of the capacitor; the other end of the capacitor is electrically connected to the negative terminal of the battery box;

[0039] One end of the pre-charging resistor R is electrically connected to the common end of the battery box and the main relay K5, and the other end of the pre-charging resistor R is electrically connected to one end of the first pre-charging relay K3; the other end of the first pre-charging relay K3 is electrically connected to one end of the second pre-charging relay K4; the other end of the second pre-charging relay K4 is electrically connected to the common end of the main relay K5 and the capacitor.

[0040] Two pre-charging relays are connected in series for pre-charging. After power failure, the adhesion of one pre-charging relay will not affect the adhesion of the other pre-charging relay, and the possibility of both pre-charging relays sticking at the same time is low, which can protect the battery box.

[0041] The first pre-charging relay K3, the second pre-charging relay K4, the main relay K5, the first protection relay K1 and the second protection relay K2 are all installed in the PDU box.

[0042] Embodiment 2 of the present invention is a PDU relay adhesion detection circuit. Based on embodiment 1, a first protection relay K1 is connected in series between the common end of the pre-charging resistor R and the main relay K5 and the battery box.

[0043] Embodiment 3 of the present invention is a PDU relay adhesion detection circuit. Based on embodiment 2, a second protection relay K2 is connected in series between the capacitor and the battery box.

[0044] By adding a dual-circuit protection relay, it can be ensured that after a power outage, there is no high voltage on the rear-end load, thus avoiding component damage.

[0045] The power-on working sequence of the first protection relay K1 and the second protection relay K2 is: after low-voltage power-on, the adhesion state of the relay is first detected. If the relay is not adhered and there is a high-voltage command, the first protection relay K1 and the second protection relay K2 are controlled to be energized. After that, pre-charging starts after the pre-charge conditions are met, and high-voltage power is applied to the load. Therefore, it is necessary to first receive the relay state and request the high-voltage command before the first protection relay K1 and the second protection relay K2 will be energized, and high voltage will be delivered to the back end. This application cannot realize power-on adhesion detection without adding other modules.

[0046] The power-off sequence for the first and second protection relays K1 and K2 is as follows: upon receiving the high-voltage power-off command, the main relay K5 is disconnected first, followed by the first and second protection relays K1 and K2. During this process, all relays are subjected to adhesion detection. The power-off adhesion detection process is simple. Once the relays are disconnected in sequence, the high-voltage power-off process is completed.

[0047] Embodiment 4 of the present invention is a PDU relay adhesion detection circuit. Based on any one of embodiments 1 to 3, the common end of the battery box and the first protection relay K1 is provided with a zero voltage detection point, the common end of the first protection relay K1, the pre-charging resistor R and the main relay K5 is provided with a first voltage detection point, the common end of the main relay K5, the second pre-charging relay K4 and the capacitor is provided with a second voltage detection point, the common end of the capacitor and the second protection relay K2 is provided with a third voltage detection point, the common end of the pre-charging resistor R and the first pre-charging relay K3 is provided with a fourth voltage detection point, and the common end of the first pre-charging relay K3 and the second pre-charging relay K4 is provided with a fifth voltage detection point.

[0048] Embodiment 5 of the present invention provides a method for detecting adhesion of a PDU relay, comprising the following steps:

[0049] Step 1: After receiving the high voltage command, disconnect the main relay K5; and obtain the voltage values U0, U1, U2, U4, and U5 of the zero voltage detection point, the first voltage detection point, the second voltage detection point, the fourth voltage detection point, and the fifth voltage detection point relative to the third voltage detection point;

[0050] If U1=U2, and U5 equals 0, the main relay K5 is stuck;

[0051] If U1=U2, and U5 is not equal to 0, then at least two of the first pre-fill relay K3, the second pre-fill relay K4 and the main relay K5 are stuck;

[0052] If U1 is not equal to U2, and U5 is equal to 0, then the first pre-charge relay K3, the second pre-charge relay K4 and the main relay K5 are not stuck;

[0053] If U1 is not equal to U2, U5 is not equal to 0, and U5 = U1, then the first pre-charge relay K3 is stuck;

[0054] If U1 is not equal to U2, U5 is not equal to 0, and U5 is not equal to U1, the second pre-charge relay K4 is stuck;

[0055] In all cases other than the above, the first pre-charge relay K3, the second pre-charge relay K4 and the main relay K5 are not adhered;

[0056] Step 2: Disconnect the first protection relay K1 and obtain the voltage value U1' of the first voltage detection point relative to the third voltage detection point at this time; if U1'=U1, the first protection relay K1 is stuck; otherwise, the first protection relay K1 is not stuck;

[0057] Step 3: Disconnect the second protection relay K2 and obtain the voltage values U0' and U1" of the zero voltage detection point and the first voltage detection point relative to the third voltage detection point at this time; if U0'=U1", the second protection relay K2 is stuck, otherwise, the second protection relay K2 is not stuck.

[0058] Embodiment 6 of the present invention provides a PDU relay adhesion detection method. Based on embodiment 5, in step 1, voltages U0, U1, U2, U4, and U5 are obtained after the main relay K5 is disconnected for 60ms-120ms.

[0059] Embodiment 7 of the present invention is a PDU relay adhesion detection method, which, based on embodiment 5 or 6, further includes step 4: storing the adhesion fault information of the first pre-filling relay K3, the second pre-filling relay K4, the main relay K5, the first protection relay K1 and the second protection relay K2.

[0060] The power-off sticking detection method is simple to handle. The sticking fault information is stored, which can be reported the next time the low-voltage switch is powered on and prompt to replace the sticking relay. The power-off sticking detection sticking fault can be stored in EEPROM.

[0061] Embodiment 8 of the present invention provides a vehicle operation control method, comprising the following steps:

[0062] Step a: Power on the low-voltage switch and read the stored adhesion fault information of the first pre-filling relay K3, the second pre-filling relay K4, the main relay K5, the first protection relay K1, and the second protection relay K2; if adhesion exists, which refers to adhesion of any one of the first pre-filling relay K3, the second pre-filling relay K4, the main relay K5, the first protection relay K1, and the second protection relay K2, disconnect the low-voltage switch, check and replace the relay with adhesion, and proceed to step b; otherwise, directly proceed to step c;

[0063] Step b: Power on the low-voltage switch and clear the stored adhesion fault information;

[0064] Step c: After receiving the high voltage command, close the second protection relay K2, the first protection relay K1, the first pre-charge relay K3 and the second pre-charge relay K4 to pre-charge the load;

[0065] Step d: When the load voltage reaches 95%, close the main relay K5 and disconnect the first pre-charge relay K3 and the second pre-charge relay K4 to power on the load with high voltage, so that the vehicle can drive normally;

[0066] Step e: Carry out steps 1-3 in sequence.

[0067] Embodiment 9 of the present invention is a method for controlling the operation of an automobile. Based on embodiment 8, in step a, if adhesion exists, an alarm light will be turned on on the PDU box.

[0068] Embodiment 10 of the present invention is a method for controlling the operation of an automobile. Based on embodiment 8 or 9, in step c, the second protection relay K2, the first protection relay K1, the first pre-filling relay K3 and the second pre-filling relay K4 are closed in sequence, and the closing time interval of the first protection relay K1 and the second protection relay K2 is 40ms-70ms, and the closing time interval of the first pre-filling relay K3 and the second pre-filling relay K4 is 40ms-70ms.

[0069] Embodiment 11 of the present invention is a method for controlling the operation of an automobile. Based on any one of Embodiments 8 to 10, in step d, the first pre-charging relay K3 and the second pre-charging relay K4 are sequentially disconnected after closing the main relay K5 for 60ms-120ms.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A PDU relay adhesion detection circuit, characterized in that: It includes a battery box, a main relay, a capacitor, a pre-charge resistor, a first pre-charge relay and a second pre-charge relay. A first protection relay is connected in series between the common end of the pre-charging resistor and the main relay and the battery box, and a second protection relay is connected in series between the capacitor and the battery box; A zero voltage detection point is provided at the common end of the battery box and the first protection relay, a first voltage detection point is provided at the common end of the first protection relay, the pre-charging resistor and the main relay, a second voltage detection point is provided at the common end of the main relay, the second pre-charging relay and the capacitor, a third voltage detection point is provided at the common end of the capacitor and the second protection relay, a fourth voltage detection point is provided at the common end of the pre-charging resistor and the first pre-charging relay, and a fifth voltage detection point is provided at the common end of the first pre-charging relay and the second pre-charging relay; One end of the main relay is electrically connected to the positive terminal of the battery box, and the other end of the main relay is electrically connected to one end of the capacitor; the other end of the capacitor is electrically connected to the negative terminal of the battery box; One end of the pre-charging resistor is electrically connected to the common end of the battery box and the main relay, and the other end of the pre-charging resistor is electrically connected to one end of the first pre-charging relay; the other end of the first pre-charging relay is electrically connected to one end of the second pre-charging relay; the other end of the second pre-charging relay is electrically connected to the common end of the main relay and the capacitor; The power-on working sequence of the first protection relay and the second protection relay is as follows: after low-voltage power-on, the sticking state of the relay is first detected. If the relay is not stuck and there is a high-voltage power-on command, the first protection relay and the second protection relay are controlled to be energized. After that, pre-charging starts after the pre-charging condition is met, and high-voltage power is applied to the load. The power-off sequence of the first and second protection relays is as follows: upon receiving the high voltage release command, the main relay is disconnected first, followed by the first and second protection relays, and all relays are subjected to adhesion detection. The adhesion detection process is as follows: Step 1: After receiving the high voltage command, disconnect the main relay; and obtain the voltage values U0, U1, U2, U4, and U5 of the zero voltage detection point, the first voltage detection point, the second voltage detection point, the fourth voltage detection point, and the fifth voltage detection point relative to the third voltage detection point; If U1=U2, and U5 equals 0, the main relay is stuck; If U1=U2, and U5 is not equal to 0, then at least two of the first pre-charge relay, the second pre-charge relay, and the main relay are stuck; If U1 is not equal to U2, and U5 is equal to 0, then the first pre-charge relay, the second pre-charge relay and the main relay are not stuck; If U1 is not equal to U2, U5 is not equal to 0, and U5=U1, then the first pre-charge relay is stuck; If U1 is not equal to U2, U5 is not equal to 0, and U5 is not equal to U1, the second pre-charge relay is stuck; In the above cases other than U1=U2 and U5=0, U1=U2 and U5 not equal to 0, U1 not equal to U2 and U5 equal to 0, U1 not equal to U2, U5 not equal to 0, and U5=U1, and U1 not equal to U2, U5 not equal to 0, and U5 not equal to U1, the first pre-charge relay, the second pre-charge relay and the main relay are not adhered; Step 2: Disconnect the first protection relay and obtain the voltage value U1' of the first voltage detection point relative to the third voltage detection point at this time; if U1'=U1, the first protection relay is stuck; otherwise, the first protection relay is not stuck; Step 3: Disconnect the second protection relay and obtain the voltage values U0' and U1'' of the zero voltage detection point and the first voltage detection point relative to the third voltage detection point at this time; if U0'=U1'', the second protection relay is stuck, otherwise, the second protection relay is not stuck.

2. A PDU relay adhesion detection method according to the PDU relay adhesion detection circuit of claim 1, characterized in that: The following steps are included: Step 1: After receiving the high voltage command, disconnect the main relay; and obtain the voltage values U0, U1, U2, U4, and U5 of the zero voltage detection point, the first voltage detection point, the second voltage detection point, the fourth voltage detection point, and the fifth voltage detection point relative to the third voltage detection point; If U1=U2, and U5 equals 0, the main relay is stuck; If U1=U2, and U5 is not equal to 0, then at least two of the first pre-charge relay, the second pre-charge relay, and the main relay are stuck; If U1 is not equal to U2, and U5 is equal to 0, then the first pre-charge relay, the second pre-charge relay and the main relay are not stuck; If U1 is not equal to U2, U5 is not equal to 0, and U5=U1, then the first pre-charge relay is stuck; If U1 is not equal to U2, U5 is not equal to 0, and U5 is not equal to U1, the second pre-charge relay is stuck; In the above cases other than U1=U2 and U5=0, U1=U2 and U5 not equal to 0, U1 not equal to U2 and U5 equal to 0, U1 not equal to U2, U5 not equal to 0, and U5=U1, and U1 not equal to U2, U5 not equal to 0, and U5 not equal to U1, the first pre-charge relay, the second pre-charge relay and the main relay are not adhered; Step 2: disconnect the first protection relay, and obtain the voltage value U1' of the first voltage detection point relative to the third voltage detection point at this time; If U1'=U1, the first protection relay is adhered, otherwise, the first protection relay is not adhered; Step 3: disconnect the second protection relay, and obtain the voltage values U0' and U1'' of the zero voltage detection point and the first voltage detection point relative to the third voltage detection point at this time; If U0'=U1'', the second protection relay is adhered, otherwise, the second protection relay is not adhered.

3. The PDU relay adhesion detection method according to claim 2, wherein: In step 1, voltages U0, U1, U2, U4, and U5 are obtained 60ms-120ms after the main relay is disconnected.

4. A PDU relay adhesion detection method according to claim 2 or 3, characterized in that: The method also includes step 4: storing adhesion fault information of the first pre-filling relay, the second pre-filling relay, the main relay, the first protection relay and the second protection relay.

5. A vehicle operation control method according to the PDU relay adhesion detection method of claim 4, characterized in that: The following steps are included: Step a: Power on the low-voltage switch and read the stored adhesion fault information of the first pre-filling relay, the second pre-filling relay, the main relay, the first protection relay, and the second protection relay; If adhesion exists, disconnect the low-voltage switch, check and replace the stuck relay, and proceed to step b; otherwise, proceed directly to step c; Step b: Power on the low-voltage switch and clear the stored adhesion fault information; Step c: upon receiving the high voltage command, closing the second protection relay, the first protection relay, the first pre-charge relay, and the second pre-charge relay to pre-charge the load; Step d: When the load voltage reaches 95%, close the main relay and disconnect the first pre-charge relay and the second pre-charge relay to power on the load with high voltage; Step e: Carry out steps 1-3 in sequence.

6. The vehicle operation control method according to claim 5, characterized in that: In step c, the second protection relay, the first protection relay, the first pre-filling relay and the second pre-filling relay are closed in sequence, and the closing time interval between the first protection relay and the second protection relay is 40ms-70ms, and the closing time interval between the first pre-filling relay and the second pre-filling relay is 40ms-70ms.

7. A vehicle operation control method according to claim 5 or 6, characterized in that: In the step d, the first pre-filling relay and the second pre-filling relay are sequentially disconnected after the main relay is closed for 60ms-120ms.

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