Pre-charging protection device, control method thereof and motor controller

Abstract

The invention discloses a pre-charging protection device and a control method thereof, and a motor controller, and the device comprises a sampling unit which obtains the pre-charging voltage of a pre-charging loop when the pre-charging loop works; after the pre-charging relay module is closed to enable the pre-charging loop to work, the control unit delays a first set time and sends out a comparison enable signal; the comparison unit is used for outputting a protection control signal under the condition that the comparison enable signal is received and the pre-charging voltage of the pre-charging loop is greater than the reference voltage set by the comparison unit; and the logic processing unit is used for controlling the pre-charging relay module to be disconnected based on the protection control signal so as to protect the pre-charging resistor module and the pre-charging loop. According to the scheme, the on-off of the pre-charging relay module is controlled by detecting whether large current flows through the pre-charging resistor module, so that the self-protection function of the pre-charging resistor module is realized, and the safety of the pre-charging resistor module and the pre-charging loop is protected.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage direct current systems, and specifically relates to a pre-charging protection device and a control method thereof, and a motor controller, and more particularly to a pre-charging resistor protection circuit and a control method thereof, a motor controller having the pre-charging resistor protection circuit, and a vehicle having the motor controller. Background Art

[0002] In the high-voltage power-on and power-off control of the high-voltage DC system, such as in new energy electric vehicles, in order to manage and control the high-voltage power-on and power-off of the entire vehicle, a high-voltage power distribution unit (PDU) is usually integrated. For some capacitive load devices, such as motor controllers, their input ports need to have large-capacity capacitors for energy storage and filtering. In the high-voltage DC system, if the main relay is directly closed, the capacitive device is in a short-circuit state at the moment of closing, generating a large impact current, causing the contacts of the main relay to stick or the device to be damaged. Therefore, a pre-charging circuit is usually connected in parallel to the main relay for capacitive loads.

[0003] In the related schemes, the pre-charging circuit is based on the protection of the main relay, but the protection of the pre-charging circuit itself is not considered. For example, when the pre-charging relay is closed, if the load is insulated or short-circuited, or starts working directly during the pre-charging relay closing phase, a large current will pass through the pre-charging circuit for a long time, causing the pre-charging resistor to heat up severely and be damaged.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The object of the present invention is to provide a pre-charging protection device and a control method thereof, and a motor controller, so as to solve the problem that in a high-voltage direct current system, the pre-charging circuit in parallel with the main relay for the capacitive load has no protection mechanism itself, and when a large current passes through the pre-charging circuit for a long time, the pre-charging resistor will be severely heated and damaged. The present invention can achieve the effect of controlling the on and off of the pre-charging relay module by detecting whether a large current flows through the pre-charging resistor module, realizing the self-protection function of the pre-charging resistor module, and protecting the safety of the pre-charging resistor module and the pre-charging circuit.

[0006] The present invention provides a pre-charging protection device, which is applied to a capacitive load device of a high-voltage direct current system; the capacitive load device comprises a busbar capacitor module, a main circuit and a pre-charging circuit, the main circuit comprises a main relay module, the pre-charging circuit comprises a pre-charging resistor module and a pre-charging relay module; the pre-charging protection device comprises: a sampling unit, a comparison unit, a logic processing unit, and a control unit; wherein the pre-charging protection function of the pre-charging protection device after the pre-charging relay module is closed comprises: the sampling unit is used to obtain the two voltages of the high-voltage direct current system when the pre-charging circuit works to charge the busbar capacitor module The voltage at the end is recorded as the bus voltage of the high-voltage DC system; the control unit is used to delay a first set time after the pre-charging relay module is closed to make the pre-charging circuit work, and send an enable signal for enabling the comparison unit, which is recorded as a comparison enable signal; the comparison unit is used to output a protection control signal when receiving the comparison enable signal and the bus voltage of the high-voltage DC system is greater than a reference voltage set by the comparison unit itself; the logic processing unit is used to disconnect the pre-charging relay module based on the protection control signal to protect the pre-charging resistor module and the pre-charging circuit.

[0007] In some embodiments, the sampling unit includes: a differential sampling module, a first operational amplifier module, a current limiting module, and a filtering module; the number of the current limiting modules is two, and the number of the filtering modules is two; wherein the first connection end and the second connection end of the input end of the differential sampling module are respectively connected to the two ends of the pre-charging resistor module; the first connection end and the second connection end of the output end of the differential sampling module are respectively connected to the in-phase input end and the inverting input end of the first operational amplifier module after passing through a corresponding one of the two current limiting modules; the in-phase input end of the first operational amplifier module is grounded after passing through one of the two filtering modules; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the other of the two filtering modules; the output end of the first operational amplifier module serves as the output end of the sampling unit;

[0008] And / or, the comparison unit includes: a first switch tube module, a second operational amplifier module, a reference voltage setting module, and a pull-down resistor module; wherein the control end of the first switch tube module serves as the enable end of the comparison unit, and is used to receive the enable signal sent by the control unit to enable the comparison unit; the output end of the sampling unit is connected to the first connection end of the first switch tube module; the second connection end of the first switch tube module is connected to the inverting input end of the second operational amplifier module; the inverting input end of the second operational amplifier module is grounded after passing through the pull-down resistor module; a preset DC power supply is connected to the non-inverting input end of the second operational amplifier module after passing through the reference voltage setting module; the output end of the second operational amplifier module serves as the output end of the comparison unit.

[0009] In some embodiments, the logic processing unit includes: a second switch tube module, and an AND logic module; wherein the output end of the comparison unit is connected to the first input end of the AND logic module; the second input end of the AND logic module is used to receive an enable signal issued by the control unit to enable the pre-charge relay module; the output end of the AND logic module is connected to the control end of the second switch tube module; the first connection end of the second switch tube module is connected to a preset DC power supply; the second connection end of the second switch tube module is connected to the control end of the pre-charge relay module.

[0010] In some embodiments, the function of the pre-charging protection module to control the closing of the pre-charging relay before the pre-charging relay module is closed includes: the sampling unit is also used to obtain the voltage across the bus capacitor module when the capacitive load device starts to power on, which is recorded as the real-time voltage of the capacitive load device; the control unit is also used to, upon receiving the closing instruction of the pre-charging relay module, if it is determined that the real-time voltage of the capacitive load device is greater than a set reference value, send an enable signal for enabling the pre-charging relay module, which is recorded as a pre-charging enable signal; and the comparison unit is also used to output a reference control signal based on the reference voltage set by the comparison unit itself when the control unit does not enable the comparison unit itself; the logic processing unit is used to close the pre-charging relay module based on the reference control signal and the pre-charging enable signal to enable the pre-charging circuit to work.

[0011] In some embodiments, the function of the pre-charging protection device to control the pre-charging process after the pre-charging relay module is closed includes: the control unit is also used to delay a second set time after the pre-charging relay module is closed to make the pre-charging circuit work, and determine whether the bus voltage of the high-voltage DC system is greater than the real-time voltage of the capacitive load device times the set coefficient: if so, control the main relay to close, and stop sending the enable signal for enabling the pre-charging relay module, and stop sending the enable signal for enabling the comparison unit; otherwise, initiate a reminder message of a pre-charging timeout fault in the pre-charging circuit, and stop sending the enable signal for enabling the pre-charging relay module, and stop sending the enable signal for enabling the comparison unit.

[0012] Matching the above-mentioned device, the present invention further provides a motor controller on the other hand, including: the pre-charging protection device mentioned above.

[0013] Matching the above-mentioned device, the present invention further provides a vehicle on the other hand, including: the pre-charging protection device mentioned above, or the motor controller mentioned above.

[0014] Matching the above-mentioned device, on the other hand, the present invention provides a control method for a pre-charging protection device, comprising: when the pre-charging circuit works to charge the bus capacitor module, obtaining the voltage across the high-voltage DC system, recorded as the bus voltage of the high-voltage DC system; after the pre-charging relay module is closed to make the pre-charging circuit work, delaying for a first set time and sending an enable signal for comparison, recorded as a comparison enable signal; when receiving the comparison enable signal, when the bus voltage of the high-voltage DC system is greater than a preset reference voltage, outputting a protection control signal; based on the protection control signal, disconnecting the pre-charging relay module to protect the pre-charging resistor module and the pre-charging circuit.

[0015] In some embodiments, it also includes: when the capacitive load device starts to power on, obtaining the voltage across the bus capacitor module, which is recorded as the real-time voltage of the capacitive load device; when receiving a closing instruction of the pre-charging relay module, if it is determined that the real-time voltage of the capacitive load device is greater than a set reference value, issuing an enable signal for enabling the pre-charging relay module, which is recorded as a pre-charging enable signal; and, when the comparison enable signal is not received, outputting a reference control signal based on a preset reference voltage; based on the reference control signal and the pre-charging enable signal, closing the pre-charging relay module to enable the pre-charging circuit to operate.

[0016] In some embodiments, it also includes: after the pre-charging relay module is closed to make the pre-charging circuit work, delaying a second set time to determine whether the bus voltage of the high-voltage DC system is greater than the real-time voltage of the capacitive load device times the set coefficient: if so, controlling the main relay to close, and stopping sending the enable signal for enabling the pre-charging relay module, and stopping sending the comparison enable signal; otherwise, initiating a reminder message of a pre-charging timeout fault in the pre-charging circuit, and stopping sending the enable signal for enabling the pre-charging relay module, and stopping sending the comparison enable signal.

[0017] Therefore, the scheme of the present invention, by targeting a capacitive load device (such as a motor controller) in a high-voltage DC system (such as a high-voltage power-on and power-off control system of a vehicle), and targeting a pre-charging circuit connected in parallel with the main circuit, a sampling circuit for sampling the voltage across the pre-charging resistor in the pre-charging circuit is set, a comparison circuit for comparing the sampling voltage of the sampling circuit with a reference voltage under the enable signal of GPIO1 of the main control chip, and a control of the closing and opening of the pre-charging relay in the pre-charging circuit based on the comparison result of the comparison circuit and the enable signal of GPIO2 of the main control chip, and in combination with the pre-charging time, so as to protect the pre-charging resistor module and the pre-charging circuit; thereby, by detecting whether a large current flows through the pre-charging resistor module to control the on and off of the pre-charging relay module, the self-protection function of the pre-charging resistor module is realized, and the safety of the pre-charging resistor module and the pre-charging circuit is protected.

[0018] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an embodiment of the pre-filling protection device of the present invention;

[0021] Figure 2 is a principle block diagram of an embodiment of a pre-charge resistance protection circuit;

[0022] Figure 3 It is a structural schematic diagram of an embodiment of a pre-charging resistance protection circuit;

[0023] Figure 4 Schematic diagram of the waveform of the capacitor charging current;

[0024] Figure 5 It is a flowchart of the execution state of the pre-charging relay;

[0025] Figure 6A schematic flow chart of an embodiment of a control method for a pre-filling protection device of the present invention;

[0026] Figure 7 It is a flow chart of an embodiment of controlling the closing of the pre-filling relay before the closing of the pre-filling relay module in the method of the present invention;

[0027] Figure 8 It is a flow chart of an embodiment of controlling the pre-charging process after the pre-charging relay module is closed in the method of the present invention;

[0028] Fig. 9 It is a structural diagram of the high voltage power supply circuit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Considering that in a high-voltage DC system, the pre-charging circuit in parallel with the main relay for capacitive loads has no protection mechanism itself, when a large current passes through the pre-charging circuit for a long time, the pre-charging resistor will be severely heated and damaged. For example: in a high-voltage DC system, the pre-charging circuit in parallel with the main relay for capacitive loads has a pre-charging resistor and a pre-charging relay. When the pre-charging relay is closed, if the load is insulated or short-circuited, or starts working directly during the closing stage of the pre-charging relay, the pre-charging circuit will pass a large current for a long time, causing the pre-charging resistor to be severely heated and damaged.

[0031] It can be seen that during the power-on process of the pre-charging circuit, due to uncontrollable situations such as short circuit or premature operation of the rear-end load, a large current will pass through the pre-charging circuit when the pre-charging relay is closed, causing the pre-charging resistor to heat up severely and be damaged.

[0032] Therefore, in order to address the problem of damage to the pre-charging circuit due to load abnormality during the pre-charging power-on process of capacitive loads in a high-voltage DC system, the present invention proposes a pre-charging protection device, specifically a pre-charging resistor protection circuit, which controls the on and off of the pre-charging relay by detecting whether a large current flows through the pre-charging resistor, thereby realizing the self-protection function of the pre-charging resistor module and ensuring the normal operation of the pre-charging circuit.

[0033] According to an embodiment of the present invention, a pre-charge protection device is provided. Figure 1A schematic diagram of the structure of an embodiment of the device of the present invention is shown. The pre-charging protection device is applied to capacitive load equipment in a high-voltage DC system; the capacitive load equipment has a bus capacitor module (such as a bus capacitor C1), a main circuit and a pre-charging circuit, the main circuit has a main relay module (such as a main relay K1), the pre-charging circuit has a pre-charging resistor module (such as a pre-charging resistor R1), and a pre-charging relay module (such as a pre-charging relay K2); the pre-charging protection device includes: a sampling unit (such as a bus voltage sampling circuit and a pre-charging voltage sampling circuit), a comparison unit (such as a comparison circuit), a logic processing unit (such as a control circuit), and a control unit (such as a main control chip). Among them, the pre-charging protection device has a pre-charging protection function after the pre-charging relay module is closed, and the function includes:

[0034] The sampling unit is used to obtain the voltage across the high-voltage direct current system when the pre-charging circuit works to charge the bus capacitor module, and record it as the bus voltage of the high-voltage direct current system.

[0035] The control unit is used to delay a first set time after the pre-charging relay module is closed to enable the pre-charging circuit to work, and send an enable signal for enabling the comparison unit, specifically, sending an enable signal for enabling the comparison unit to turn on the pre-charging protection function of the pre-charging protection device, which is recorded as a comparison enable signal (such as enabling the GPIO1 pin to turn on the transistor Q2); wherein, the first set time is such as the delay time T of the main control chip.

[0036] The comparison unit is used to output a protection control signal when receiving the comparison enable signal, that is, when the control unit enables the comparison unit itself and when the bus voltage of the high-voltage DC system is greater than the reference voltage set by the comparison unit itself; for example: see Figure 3 In the example shown, the pre-charge resistance protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 outputs a low level.

[0037] The logic processing unit is used to disconnect the pre-charging relay module based on the protection control signal to protect the pre-charging resistor module and the pre-charging circuit. Figure 3 In the example shown, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor.

[0038] The solution of the present invention proposes a pre-charging resistor protection circuit, which controls the on-off of the pre-charging relay by detecting whether a large current flows through the pre-charging resistor, realizes the self-protection function of the pre-charging resistor module, avoids the pre-charging resistor being damaged by a large current flowing through the pre-charging circuit, and ensures the normal operation of the pre-charging circuit. Thus, the self-protection function of the pre-charging circuit is realized, and the pre-charging circuit is prevented from being damaged and failing.

[0039] In some embodiments, the sampling unit includes: a differential sampling module (such as a differential sampling chip U1), a first operational amplifier module (such as an operational amplifier U2), a current limiting module (such as a resistor R2 and a resistor R4), and a filtering module (such as an RC filter composed of a resistor R3 and a capacitor C2, a resistor R5 and a capacitor C3).

[0040] Among them, the first connection end and the second connection end of the input end of the differential sampling module are respectively connected to the two ends of the pre-charging resistor module; the first connection end and the second connection end of the output end of the differential sampling module are respectively connected to the in-phase input end and the inverting input end of the first operational amplifier module after passing through a corresponding one of the two current limiting modules; the in-phase input end of the first operational amplifier module is grounded after passing through one of the two filtering modules; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the other of the two filtering modules; the output end of the first operational amplifier module serves as the output end of the sampling unit.

[0041] Figure 3 FIG. 1 is a schematic diagram of the structure of an embodiment of a pre-charge resistance protection circuit. Figure 3 As shown, in the load circuit, the positive electrode of the high-voltage DC power supply is connected to the second connection end of the bus capacitor C1 after the parallel main circuit and pre-charging circuit; the negative electrode of the high-voltage DC power supply is connected to the first connection end of the bus capacitor C1. The bus capacitor C1 is connected in parallel with the load. In the main circuit, the fuse F1 and the main relay K1 are arranged in series between the positive electrode of the high-voltage DC power supply and the second connection end of the bus capacitor C1. In the pre-charging circuit, the pre-charging resistor R1 and the pre-charging relay K2 are connected in series between the positive electrode of the high-voltage DC power supply and the second connection end of the bus capacitor C1.

[0042] In such Figure 3In the pre-charge resistance protection circuit shown, the sampling circuit includes: a differential sampling chip U1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, a capacitor C3, and an operational amplifier U2. The first connection end of the resistor R1 is connected to the positive electrode of the high-voltage DC power supply, and the second connection end of the resistor R1 is connected to the pre-charge relay K2. The first connection end of the resistor R1 is connected to the first connection end of the input end of the differential sampling chip U1; the second connection end of the resistor R1 is connected to the second connection end of the input end of the differential sampling chip U1; the first connection end of the output end of the differential sampling chip U1 is connected to the non-inverting input end of the operational amplifier U2 through the resistor R2; the second connection end of the output end of the differential sampling chip U1 is connected to the inverting input end of the operational amplifier U2 through the resistor R4. The non-inverting input end of the operational amplifier U2 is grounded after the capacitor C2 and the resistor R3 are connected in parallel; the inverting input end of the operational amplifier U2 is connected to the output end of the operational amplifier U2 after the resistor R5 and the capacitor C3 are connected in parallel. The output terminal of the operational amplifier U2 is connected to the input terminal of the comparison circuit.

[0043] The differential sampling chip U1 is a differential isolation chip, which inputs a differential signal at one end and outputs a differential signal at the other end, and the two differential signals are proportional and isolated. For example, the differential sampling chip U1 can use an optocoupler of model ACPL-C87H.

[0044] In the scheme of the present invention, the pre-charging voltage at both ends of the pre-charging resistor is detected by the sampling unit, and then it is determined whether a large current flows through the pre-charging resistor, so as to control the on and off of the pre-charging relay, realize the self-protection function of the pre-charging resistor module, realize the self-protection function of the pre-charging circuit, avoid damage and failure of the pre-charging circuit, and ensure the normal operation of the pre-charging circuit.

[0045] In some embodiments, the comparison unit includes: a first switch tube module (such as transistor Q2), a second operational amplifier module (such as operational amplifier U3), a reference voltage setting module (such as resistor R8 and resistor R7), and a pull-down resistor module (such as resistor R6).

[0046] Among them, the control end of the first switch tube module (such as the base of the transistor Q2) is used as the enable end of the comparison unit to receive the enable signal sent by the control unit to enable the comparison unit; the output end of the sampling unit is connected to the first connection end of the first switch tube module (such as the collector of the transistor Q2); the second connection end of the first switch tube module (such as the emitter of the transistor Q2) is connected to the inverting input end of the second operational amplifier module; the inverting input end of the second operational amplifier module is grounded after passing through the pull-down resistor module. The preset DC power supply is connected to the non-inverting input end of the second operational amplifier module after passing through the reference voltage setting module; the output end of the second operational amplifier module serves as the output end of the comparison unit.

[0047] like Figure 3 As shown, the comparison circuit includes: transistor Q2, resistor R6, resistor R7, resistor R8, and operational amplifier U3. The collector of transistor Q2 serves as the input end of the comparison circuit. The base of transistor Q2 is connected to the control pin MCU.GPIO1 of the main control chip. The emitter of transistor Q2 is connected to the inverting input end of operational amplifier U3. The inverting input end of operational amplifier U3 is grounded after passing through resistor R6. The power supply VCC is grounded after passing through resistor R8 and resistor R7, and the common end of resistor R8 and resistor R7 is connected to the non-inverting input end of operational amplifier U3. The output end of operational amplifier U3 is connected to the input end of the control circuit.

[0048] In the scheme of the present invention, after sampling the pre-charging voltage on the pre-charging resistor, the comparison unit is used to detect whether a large current flows through the pre-charging resistor to control the on and off of the pre-charging relay, thereby realizing the self-protection function of the pre-charging resistor module, avoiding damage to the pre-charging resistor due to a large current flowing through the pre-charging circuit, and ensuring the normal operation of the pre-charging circuit.

[0049] In some implementations, the logic processing unit includes: a second switch tube module (such as transistor Q1 ) and an AND logic module (such as AND gate U4 ).

[0050] Among them, the output end of the comparison unit is connected to the first input end of the AND logic module; the second input end of the AND logic module is used to receive an enable signal issued by the control unit to enable the pre-charge relay module; the output end of the AND logic module is connected to the control end of the second switch tube module (such as the base of the transistor Q1).

[0051] The first connection end of the second switch tube module (such as the collector of the transistor Q1) is connected to a preset DC power supply; the second connection end of the second switch tube module (such as the emitter of the transistor Q1) is connected to the control end of the pre-charging relay module (such as the coil end of the pre-charging relay K2).

[0052] like Figure 3 As shown, the control circuit includes: a transistor Q1 and an AND gate U4. The first input end of the AND gate U4 serves as the input end of the control circuit. The second input end of the AND gate U4 is connected to the control pin MCU.GPIO2 of the main control chip. The output end of the AND gate U4 is connected to the base of the transistor Q1. The collector of the transistor Q1 is connected to the power supply VCC; the emitter of the transistor Q1, as the output end of the control circuit, is connected to the control end of the pre-charge relay K2, which is used to control the closing and opening of the pre-charge relay K2.

[0053] exist Figure 3In the example shown, conventional circuits can be used for the sampling circuit and the comparison circuit; the control circuit of the pre-filling relay is conventionally controlled by the GPIO of the main control chip, and in the solution of the present invention, a hardware circuit is added to control the GPIO of the main control chip at the same time. When the pre-filling relay K2 is closed and the main relay K1 is not closed, if there is current passing through the pre-filling circuit, a voltage drop will occur across the pre-filling resistor R1. This pre-filling resistor protection circuit is based on sampling the voltage difference across the pre-filling resistor R1. According to the formula I=U / R, the current of the pre-filling circuit can be calculated, so the sampling circuit can be equivalent to current sampling. The entire pre-filling resistor protection circuit is equivalent to limiting the current passing through the pre-filling circuit. When the current exceeds the preset threshold, the pre-filling relay K2 is immediately disconnected, thereby achieving the effect of protecting the pre-filling circuit.

[0054] If the threshold value of the current that can flow through the pre-charge circuit for a long time is Iref, then the voltage U across the pre-charge resistor R1 is R1 =R1*Iref, in the sampling circuit, the differential sampling chip U1 plays a role in high-voltage isolation, the capacitors C2 and C3 in the operational amplifier circuit are used for filtering and voltage stabilization, the resistance values ​​of the resistors R2=R4, R3=R5, then the voltage output to the negative end of the comparison circuit is Uref-=U R1 *R3 / R2, this voltage is also the reference voltage Uref obtained by connecting the resistor R7 and the resistor R8 in series to the VCC voltage divider in the comparison circuit. When the transistor Q2 is turned on, when the current of the pre-charge loop exceeds Iref, the voltage of the negative pin of the operational amplifier U3 is greater than Uref, and the operational amplifier U3 outputs a low level, which will turn off the transistor Q1, thereby protecting the pre-charge resistor R1.

[0055] According to the RC circuit principle, the formula for charging the bus capacitor C1 is:

[0056]

[0057] Among them, Udc is the bus voltage, I1 is the loop current when the bus capacitor C1 is charged, R1 is the resistance value of the resistor R1, C1 is the capacitance value of the bus capacitor C1, the time constant τ=R1C1 of the RC circuit, and t is the charging time. Figure 4 The following is a schematic diagram of the waveform of the capacitor charging current. From the current formula, we can see that at the moment when the pre-charging relay K2 is closed, a relatively large current will appear, such as Figure 4As shown, as the charging progress of the RC circuit decreases rapidly, if the pre-charge resistor protection circuit is directly enabled, the protection logic will be triggered by mistake, causing the pre-charge circuit to be unable to power on. Therefore, combined with the charging time of the RC circuit, after the pre-charge relay K2 is closed for T = R1*C1 time, the main control chip enables GPIO1 and turns on the transistor Q2 to start the pre-charge resistor protection circuit. From the voltage formula, it can be seen that the charging time of the bus capacitor C1 is usually t = 3τ ~ 5τ to meet the charging demand, at this time U1 ≈ 0.95U dc ~0.99U dc Therefore, after the pre-charging relay K2 is closed for 5*R1*C1, the pre-charging voltage can be detected to determine whether the pre-charging is completed. Fig. 9 It is a structural diagram of the high voltage power supply circuit, such as Fig. 9 As shown in the figure, U1 represents the real-time voltage across the bus capacitor during the charging process. Udc is the bus voltage, provided by the high-voltage DC power supply system; U1 is the real-time voltage across the bus capacitor C1, and before charging begins, U1 = 0; after charging begins, the voltage U1 changes according to the charging formula, and when fully charged, U1 = Udc.

[0058] In the scheme of the present invention, the logic processing unit is used to perform logical judgment in combination with the output of the comparison unit and the enable signal of the control unit to control the closing and opening of the pre-charging relay module, thereby realizing the self-protection function of the pre-charging resistor module, avoiding damage to the pre-charging resistor due to large current flowing through the pre-charging circuit, and ensuring the normal operation of the pre-charging circuit.

[0059] In some embodiments, the pre-filling protection device described in the solution of the present invention further has a function of controlling the closing of the pre-filling relay before the pre-filling relay module is closed, and the function specifically includes:

[0060] The sampling unit is also used to obtain the voltage across the bus capacitor module when the capacitive load device starts to be powered on, and record it as the real-time voltage of the capacitive load device (such as U1).

[0061] The control unit is also used for, upon receiving the closing instruction of the pre-charging relay module, if it is determined that the real-time voltage of the capacitive load device is greater than the set reference value, issuing an enable signal for enabling the pre-charging relay module, specifically issuing an enable signal for enabling the pre-charging relay module to start the pre-charging function of the pre-charging circuit, recorded as a pre-charging enable signal (such as the main control chip controlling GPIO2 to enable to output a high level); wherein, the closing instruction of the pre-charging relay module is an instruction for closing the pre-charging relay module. And,

[0062] The comparison unit is further configured to output a reference control signal based on a reference voltage set by the comparison unit itself when the control unit does not enable the comparison unit itself. Figure 3 In the example shown, transistor Q2 is not turned on, the negative pin of voltage comparison chip U3 (ie, operational amplifier U3) is pulled low by resistor R6, and the negative pin voltage of operational amplifier U3 is less than reference voltage Uref, so operational amplifier U3 outputs a high level.

[0063] The logic processing unit is used to close the pre-filling relay module based on the reference control signal and the pre-filling enable signal to make the pre-filling circuit work. Wherein, when the pre-filling circuit works, the main circuit does not work, that is, the main relay module is disconnected.

[0064] Specifically, the function of closing the pre-filling relay module and performing pre-filling protection after the pre-filling relay is closed includes:

[0065] The sampling unit is used to obtain the voltage across the bus capacitor module when the capacitive load device starts to power on, and record it as the real-time voltage of the capacitive load device (such as U1); and, when the pre-charging loop is working, obtain the voltage across the high-voltage DC system, and record it as the bus voltage of the high-voltage DC system (such as Udc); in addition, the voltage across the pre-charging resistor is used to calculate the current passing through the pre-charging resistor according to U=R*I.

[0066] The control unit is used to, upon receiving the closing instruction of the pre-filling relay module, send out an enable signal for enabling the pre-filling relay module if it is determined that the real-time voltage of the capacitive load device is greater than a set reference value. Specifically, it sends out an enable signal for enabling the pre-filling relay module to start the pre-filling function of the pre-filling circuit, which is recorded as a pre-filling enable signal (such as the main control chip controlling GPIO2 to enable and output a high level); wherein, the closing instruction of the pre-filling relay module is an instruction for closing the pre-filling relay module. And,

[0067] The comparison unit is used to output a reference control signal based on a reference voltage set by the comparison unit itself when the control unit does not enable the comparison unit itself; for example: Figure 3 In the example shown, transistor Q2 is not turned on, the negative pin of voltage comparison chip U3 (ie, operational amplifier U3) is pulled low by resistor R6, and the negative pin voltage of operational amplifier U3 is less than reference voltage Uref, so operational amplifier U3 outputs a high level.

[0068] The logic processing unit is used to close the pre-charging relay module based on the reference control signal and the pre-charging enable signal to enable the pre-charging circuit to operate; wherein, when the pre-charging circuit is operating, the main circuit is not operating, that is, the main relay module is disconnected.

[0069] The control unit is also used to delay a first set time after the pre-charge relay module is closed, and send an enable signal for enabling the comparison unit, specifically, sending an enable signal for enabling the comparison unit to turn on the pre-charge protection function of the pre-charge protection device, which is recorded as a comparison enable signal (such as enabling the GPIO1 pin to turn on the transistor Q2); wherein, the first set time is such as the delay time T of the main control chip.

[0070] The comparison unit is further used to output a protection control signal when the control unit enables the comparison unit itself and the bus voltage of the high-voltage DC system is greater than the reference voltage set by the comparison unit itself; for example: Figure 3 In the example shown, the pre-charge resistance protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 outputs a low level.

[0071] The logic processing unit is further configured to disconnect the pre-charging relay module based on the protection control signal to protect the pre-charging resistor module and the pre-charging circuit. Figure 3 In the example shown, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor.

[0072] Figure 2 1 is a principle block diagram of an embodiment of a pre-charge resistor protection circuit, specifically a principle block diagram of a pre-charge resistor protection circuit for a new energy vehicle. Figure 2 As shown in FIG. 1 , it is an electrical schematic diagram of a load circuit in a PDU module. A conventional load circuit includes a pre-charging circuit, a bus capacitor and a load. The pre-charging circuit includes a pre-charging resistor and a pre-charging relay connected in series. The solution of the present invention is to set a sampling circuit, a comparison circuit and a control circuit for the pre-charging circuit. Figure 2In the example shown, the first connection terminal of the output terminal of the high-voltage DC power supply is connected to the first connection terminal of the power supply terminal of the load through the main relay; the pre-charging resistor and the pre-charging relay are connected in series and then connected in parallel with the main relay; the sampling circuit is used to sample the voltage across the pre-charging resistor and transmit it to the comparison circuit, the comparison circuit is used to compare the sampled voltage across the pre-charging resistor with the set reference voltage to obtain a comparison result, and the control circuit is used to control the closing and opening of the pre-charging relay according to the comparison result. The second connection terminal of the output terminal of the high-voltage DC power supply is connected to the second connection terminal of the power supply terminal of the load; the bus capacitor is connected in parallel with the load and is set at the power supply terminal of the load. A voltage sampling circuit is connected in parallel on the input side of the bus capacitor, and the voltage sampling circuit is used to detect the real-time voltage U1 across the bus capacitor C1.

[0073] The bus capacitor C1 is connected in parallel with the load, and then in series with the pre-charging circuit, and then connected to the high-voltage power battery, wherein the pre-charging circuit includes a pre-charging circuit composed of a pre-charging resistor R1 and a pre-charging relay K2, and a main circuit composed of a fuse F1 and a main relay K1. The pre-charging circuit is used to protect against instantaneous current shocks caused by high-voltage closure, and the main circuit is used to power the load for a long time. If a large current passes through the pre-charging circuit for a long time, the pre-charging resistor will heat up severely and be damaged. Therefore, the solution of the present invention adds a pre-charging resistor protection circuit at both ends of the pre-charging resistor R1 on the basis of the conventional electrical architecture. The pre-charging resistor protection circuit is composed of a sampling circuit, a comparison circuit and a pre-charging relay control circuit, and the specific circuit is as follows Figure 3 shown.

[0074] Figure 5 The following is a flow chart of the execution status of the pre-charging relay. Figure 5 As shown, the process of the execution state of the pre-charging relay K2 includes:

[0075] Step 1: After receiving the instruction to close the pre-charging relay K2, execute step 2.

[0076] Step 2, determine whether the bus voltage Udc> the set reference value Udc_ref: if yes, execute step 3; otherwise return to step 2, that is, if the bus voltage Udc is less than or equal to the set reference value Udc_ref, do not respond to the command to close the pre-charge relay K2, and stay in a waiting state. Among them, the main control chip has been sampling the bus voltage Udc, and will not determine whether the bus voltage Udc> the set reference value Udc_ref until it receives the closing command.

[0077] Step 3. If the bus voltage Udc>the set reference value Udc_ref, the main control chip controls GPIO2 to enable and output a high level. At this time, the transistor Q2 is not turned on, and the negative pin of the voltage comparison chip U3 (i.e., the operational amplifier U3) is pulled down by the resistor R6. The negative pin voltage of the operational amplifier U3 is less than the reference voltage Uref. Therefore, the operational amplifier U3 outputs a high level. The chip U4 (i.e., the AND gate U4) performs AND logic on the GPIO2 level and the output level of the operational amplifier U3. The AND gate U4 outputs a high level to turn on the transistor Q1, which can control the pre-charge relay K2 to close, and then execute step 4.

[0078] Among them, Udc_ref is the reference voltage of the bus voltage. For example, if the bus voltage Udc is 540V, Udc_ref can be set to 400V; Uref is equivalent to the reference value of the pre-charging resistor overcurrent. According to U=R*I, the pre-charging resistor is multiplied by the current passing through it to obtain the voltage across the pre-charging resistor. The voltage after the sampling amplifier is compared with the reference value Uref to determine whether there is overcurrent. Uref is obtained by dividing the VCC voltage by resistors R7 and R8. VCC is a low voltage; Udc_ref is greater than Uref.

[0079] In step 2 and step 3, after receiving the instruction to close the pre-charging relay K2, if it is determined that the bus voltage Udc is relatively small, the instruction is not responded to in order to protect the safety of the vehicle's electricity use. The low bus voltage Udc may be due to: battery power consumption resulting in very low voltage, controller front-end power supply disconnection, other component failures requiring power off, etc. At this time, the pre-charging relay may not respond to the instruction request. When the bus voltage Udc is higher than the set reference value (such as the set reference value Udc_ref), the controller responds to the instruction, controls the pre-charging relay K2 to close, and starts charging.

[0080] Step 4. After the pre-charge relay K2 is closed, the main control chip delays for a time period of T, and then enables the GPIO1 pin to turn on the transistor Q2, and then executes step 5. After the pre-charge relay K2 is closed, the main control chip delays for a time period of T, and then enables the GPIO1 pin to turn on the transistor Q2. At this time, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the negative pin voltage of the operational amplifier U3 is greater than Uref, then the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor. According to Figure 4As shown, a large current will be generated at the moment of charging the bus capacitor, and the charging current will gradually decrease. The function of the pre-charging resistor R1 is to prevent the large current from impacting the bus capacitor and causing damage to the capacitor, but the pre-charging resistor R1 cannot pass a large current for a long time, otherwise it will be severely heated and damaged. After the delay time T = RC, the current has been reduced a lot, and a large current will not appear under normal circumstances. At this time, the pre-charging resistor protection circuit is enabled to ensure that: on the one hand, the large current generated at the moment of charging will not trigger the protection by mistake; on the other hand, the large current generated during the charging process can immediately disconnect the pre-charging relay K2 to protect the pre-charging resistor R1 and the pre-charging circuit.

[0081] In the scheme of the present invention, a voltage detection module (such as a sampling circuit), a voltage comparison module (such as a comparison circuit), and a logic and gate module (such as a control circuit) are added to both ends of the pre-charging resistor of the pre-charging circuit. When controlling the closing of the pre-charging relay, the voltage at both ends of the pre-charging resistor is detected and compared with the reference voltage value set by the hardware, and then the control level obtained by the comparison and the control level output by the control pin of the main chip are ANDed, and the control signal for controlling the closing and disconnection of the pre-charging relay is output. If a large current appears for a long time during the closing stage of the pre-charging relay, the pre-charging relay can be quickly controlled to be turned off through the designed hardware sampling and comparison circuit to avoid damage to the pre-charging resistor and cause failure of the pre-charging circuit, thereby realizing the self-protection function of the pre-charging circuit.

[0082] In some embodiments, the pre-charging protection device described in the solution of the present invention further has the function of controlling the pre-charging process after the pre-charging relay module is closed, and the function specifically includes:

[0083] The control unit is also used to delay a second set time after the pre-charging relay module is closed to make the pre-charging circuit work, to determine whether the bus voltage of the high-voltage DC system is greater than the real-time voltage of the capacitive load device times the set coefficient: if so, control the main relay to close, and stop sending the enable signal for enabling the pre-charging relay module, and stop sending the enable signal for enabling the comparison unit; otherwise, initiate a reminder message of a pre-charging timeout fault in the pre-charging circuit, and stop sending the enable signal for enabling the pre-charging relay module, and stop sending the enable signal for enabling the comparison unit. Among them, the first set time is such as T=R1C1, the second set time is such as 5T, and the set coefficient is such as 0.9.

[0084] like Figure 5As shown, the process of the execution status of the pre-charging relay K2 also includes: Step 5, detecting the voltage across the pre-charging resistor R1 as the pre-charging voltage, and the main control chip determines that if the pre-charging voltage is greater than 0.9*Udc after closing the pre-charging relay K2 for a period of time, the main relay K1 is closed, and then the pre-charging relay K2 is disconnected and the transistor Q2 is turned off to complete the normal power-on process; if the pre-charging voltage is less than or equal to 0.9Udc, a pre-charging timeout fault is reported. This fault may be caused by abnormal conditions such as large current in the pre-charging circuit, voltage sampling circuit failure, and disconnection of the DC high voltage power supplied to the controller. Similarly, the pre-charging relay K2 is disconnected and the transistor Q2 is turned off, and the pre-charging relay K2 can be closed again after waiting for reset (that is, after the fault is cleared, it can be powered on again after the weak current is turned off).

[0085] In step 5, after closing the pre-charge relay K2 for a period of time, it can be specifically calculated according to the above formula that after 3 to 5 times of RC time, the bus capacitor charging voltage has reached 0.95-0.99 times the bus voltage, and the charging current is already very small. At this time, the main relay K1 is closed, and no damage to the capacitor or relay is caused. Then the pre-charge relay K2 can be disconnected. When the load is started, the large current is passed through the main relay K1. If the voltage obtained by sampling is relatively low within a period of time, a fault may have occurred during the pre-charge process, and a pre-charge timeout fault is reported, and the pre-charge relay K2 is disconnected, and the power is turned on again after restarting. The scheme of the present invention, taking the pre-charging circuit of new energy vehicles as an example, is not limited to this situation, and some other high-voltage DC systems (such as air-conditioning systems, photovoltaic systems, etc.) are also applicable.

[0086] In the scheme of the present invention, the pre-charging resistor is connected in series with the pre-charging relay to detect the voltage across the pre-charging resistor, that is, the voltage across the pre-charging resistor in the pre-charging circuit is sampled. When there is a large current in the pre-charging circuit, the hardware circuit will quickly turn off the pre-charging relay, effectively reducing the damage to the controller; and the time for enabling the pre-charging resistor protection circuit is controlled to effectively prevent false triggering of the protection. Specifically, when the closing instruction of the pre-charging relay is received, if the bus voltage is lower than the preset voltage, the closing of the pre-charging relay will not be responded to; the pre-charging relay will be closed after the bus voltage is higher than the preset voltage, and the pre-charging resistor protection circuit will be enabled after the pre-charging relay is closed for T=RC time. If the load is short-circuited during the pre-charging of the bus capacitor during the closing stage of the pre-charging relay or the load starts to generate a large current, the pre-charging relay can be quickly controlled to be turned off to avoid damage to the pre-charging resistor and cause failure of the pre-charging circuit, thereby realizing the self-protection function of the pre-charging circuit.

[0087] By adopting the technical solution of the present invention, a sampling circuit for sampling the voltage across the pre-charging resistor in the pre-charging circuit is set for a capacitive load device (such as a motor controller) in a high-voltage DC system (such as a high-voltage power-on and power-off control system of a vehicle) and a pre-charging circuit connected in parallel with the main circuit. A comparison circuit is used to compare the sampled voltage of the sampling circuit with a reference voltage under the enable signal of GPIO1 of the main control chip. The comparison result of the comparison circuit and the enable signal of GPIO2 of the main control chip are used to control the closing and opening of the pre-charging relay in the pre-charging circuit based on the comparison signal of the comparison circuit and the enable signal of GPIO2 of the main control chip, and in combination with the pre-charging time, so as to protect the pre-charging resistor module and the pre-charging circuit. Thus, by detecting whether a large current flows through the pre-charging resistor module to control the on and off of the pre-charging relay module, the self-protection function of the pre-charging resistor module is realized, and the safety of the pre-charging resistor module and the pre-charging circuit is protected.

[0088] According to an embodiment of the present invention, a motor controller corresponding to the pre-filling protection device is also provided. The motor controller may include: the pre-filling protection device described above.

[0089] Since the processing and functions implemented by the motor controller of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0090] According to an embodiment of the present invention, a vehicle corresponding to the pre-filling protection device is also provided. The vehicle may include: the pre-filling protection device described above, or the motor controller described above.

[0091] Since the processing and functions implemented by the vehicle of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0092] According to an embodiment of the present invention, a control method for a pre-filling protection device corresponding to the pre-filling protection device is also provided, such as Figure 6 The control method of the pre-filling protection device may include: the pre-filling protection function after the pre-filling relay module is closed, specifically as follows: step S110 to step S140.

[0093] In step S110, when the pre-charging circuit works to charge the bus capacitor module, the voltage across the high-voltage direct current system is obtained and recorded as the bus voltage of the high-voltage direct current system.

[0094] At step S120, after the pre-charge relay module is closed to enable the pre-charge circuit to work, a first set time is delayed and an enable signal for comparison is issued, specifically, an enable signal for enabling the comparison unit to turn on the pre-charge protection function of the pre-charge protection device is issued, which is recorded as a comparison enable signal (such as enabling the GPIO1 pin to turn on the transistor Q2); wherein, the first set time is such as the main control chip delay time T.

[0095] At step S130, when the comparison enable signal is received, that is, when the control unit enables the comparison unit itself, and when the bus voltage of the high-voltage DC system is greater than the preset reference voltage, a protection control signal is output; that is, when the bus voltage of the high-voltage DC system is greater than the reference voltage set by the comparison unit itself, a protection control signal is output. For example: See Figure 3 In the example shown, the pre-charge resistance protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 outputs a low level.

[0096] At step S140, based on the protection control signal, the pre-charging relay module is disconnected to protect the pre-charging resistor module and the pre-charging circuit. Figure 3 In the example shown, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor.

[0097] The solution of the present invention proposes a pre-charging resistor protection circuit, which controls the on-off of the pre-charging relay by detecting whether a large current flows through the pre-charging resistor, realizes the self-protection function of the pre-charging resistor module, avoids the pre-charging resistor being damaged by a large current flowing through the pre-charging circuit, and ensures the normal operation of the pre-charging circuit. Thus, the self-protection function of the pre-charging circuit is realized, and the pre-charging circuit is prevented from being damaged and failing.

[0098] In some embodiments, the control method of the pre-filling protection device described in the solution of the present invention also includes: a function of controlling the closing of the pre-filling relay before the pre-filling relay module is closed, see the following exemplary description for details.

[0099] Combine the following Figure 7 The flowchart of an embodiment of controlling the closing of the pre-filling relay before the closing of the pre-filling relay module in the method of the present invention is shown, which further illustrates the specific process of controlling the closing of the pre-filling relay before the closing of the pre-filling relay module, including: step S210 to step S240.

[0100] Step S210, when the capacitive load device starts to be powered on, the voltage across the bus capacitor module is obtained and recorded as the real-time voltage (such as Udc) of the capacitive load device.

[0101] Step S220, when receiving the closing instruction of the pre-filling relay module, if it is determined that the real-time voltage of the capacitive load device is greater than the set reference value, an enable signal for enabling the pre-filling relay module is issued, specifically, an enable signal for enabling the pre-filling relay module to start the pre-filling function of the pre-filling circuit is issued, which is recorded as a pre-filling enable signal (such as the main control chip controls GPIO2 to enable to output a high level); wherein, the closing instruction of the pre-filling relay module is an instruction for closing the pre-filling relay module. And,

[0102] Step S230, when the comparison enable signal is not received, that is, when the control unit does not enable the comparison unit itself, outputting a reference control signal based on a preset reference voltage, that is, outputting a reference control signal based on the reference voltage set by the comparison unit itself; for example: see Figure 3 In the example shown, transistor Q2 is not turned on, the negative pin of voltage comparison chip U3 (ie, operational amplifier U3) is pulled low by resistor R6, and the negative pin voltage of operational amplifier U3 is less than reference voltage Uref, so operational amplifier U3 outputs a high level.

[0103] Step S240, based on the reference control signal and the pre-charge enable signal, the pre-charge relay module is closed to enable the pre-charge circuit to operate. Wherein, when the pre-charge circuit is operating, the main circuit is not operating, that is, the main relay module is disconnected.

[0104] Specifically, the function of closing the pre-filling relay module and performing pre-filling protection after the pre-filling relay is closed includes:

[0105] By means of the sampling unit, when the capacitive load device starts to be powered on, the voltage across the bus capacitor module is obtained, which is recorded as the real-time voltage (such as Udc) of the capacitive load device; and when the pre-charging loop is working, the voltage across the high-voltage direct current system is obtained, which is recorded as the bus voltage of the high-voltage direct current system;

[0106] Through the control unit, when receiving the closing instruction of the pre-filling relay module, if it is determined that the real-time voltage of the capacitive load device is greater than the set reference value, an enable signal for enabling the pre-filling relay module is issued, specifically, an enable signal for enabling the pre-filling relay module to start the pre-filling function of the pre-filling circuit is issued, which is recorded as a pre-filling enable signal (such as the main control chip controls GPIO2 to enable to output a high level); wherein, the closing instruction of the pre-filling relay module is an instruction for closing the pre-filling relay module. And,

[0107] By means of the comparison unit, when the control unit does not enable the comparison unit itself, a reference control signal is output based on a reference voltage set by the comparison unit itself; for example: Figure 3 In the example shown, transistor Q2 is not turned on, the negative pin of voltage comparison chip U3 (ie, operational amplifier U3) is pulled low by resistor R6, and the negative pin voltage of operational amplifier U3 is less than reference voltage Uref, so operational amplifier U3 outputs a high level.

[0108] Through the logic processing unit, based on the reference control signal and the pre-charge enable signal, the pre-charge relay module is closed to enable the pre-charge circuit to work; wherein, when the pre-charge circuit is working, the main circuit is not working, that is, the main relay module is disconnected.

[0109] Through the control unit, after the pre-charge relay module is closed, the first set time is delayed and an enable signal for enabling the comparison unit is sent, specifically, an enable signal for enabling the comparison unit to turn on the pre-charge protection function of the pre-charge protection device is sent, which is recorded as a comparison enable signal (such as enabling the GPIO1 pin to turn on the transistor Q2); wherein, the first set time is such as the delay time T of the main control chip.

[0110] By means of the comparison unit, when the control unit enables the comparison unit itself, when the bus voltage of the high voltage DC system is greater than the reference voltage set by the comparison unit itself, a protection control signal is output; for example: see Figure 3 In the example shown, the pre-charge resistance protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 outputs a low level.

[0111] The logic processing unit also disconnects the pre-charging relay module based on the protection control signal to protect the pre-charging resistor module and the pre-charging circuit. Figure 3In the example shown, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the voltage at the negative pin of the operational amplifier U3 is greater than Uref, the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor.

[0112] Figure 2 1 is a principle block diagram of an embodiment of a pre-charge resistor protection circuit, specifically a principle block diagram of a pre-charge resistor protection circuit for a new energy vehicle. Figure 2 As shown in FIG. 1 , it is an electrical schematic diagram of a load circuit in a PDU module. A conventional load circuit includes a pre-charging circuit, a bus capacitor and a load. The pre-charging circuit includes a pre-charging resistor and a pre-charging relay connected in series. The solution of the present invention is to set a sampling circuit, a comparison circuit and a control circuit for the pre-charging circuit. Figure 2 In the example shown, the first connection terminal of the output terminal of the high-voltage DC power supply is connected to the first connection terminal of the power supply terminal of the load through the main relay; the pre-charging resistor and the pre-charging relay are connected in series and then connected in parallel with the main relay; the sampling circuit is used to sample the voltage across the pre-charging resistor and transmit it to the comparison circuit, the comparison circuit is used to compare the sampled voltage across the pre-charging resistor with the set reference voltage to obtain a comparison result, and the control circuit is used to control the closing and opening of the pre-charging relay according to the comparison result. The second connection terminal of the output terminal of the high-voltage DC power supply is connected to the second connection terminal of the power supply terminal of the load; the bus capacitor is connected in parallel with the load and is set at the power supply terminal of the load. A voltage sampling circuit is connected in parallel on the input side of the bus capacitor, and the voltage sampling circuit is used to detect the real-time voltage U1 across the bus capacitor C1.

[0113] The bus capacitor C1 is connected in parallel with the load, and then in series with the pre-charging circuit, and then connected to the high-voltage power battery, wherein the pre-charging circuit includes a pre-charging circuit composed of a pre-charging resistor R1 and a pre-charging relay K2, and a main circuit composed of a fuse F1 and a main relay K1. The pre-charging circuit is used to protect against instantaneous current shocks caused by high-voltage closure, and the main circuit is used to power the load for a long time. If a large current passes through the pre-charging circuit for a long time, the pre-charging resistor will heat up severely and be damaged. Therefore, the solution of the present invention adds a pre-charging resistor protection circuit at both ends of the pre-charging resistor R1 on the basis of the conventional electrical architecture. The pre-charging resistor protection circuit is composed of a sampling circuit, a comparison circuit and a pre-charging relay control circuit, and the specific circuit is as follows Figure 3 shown.

[0114] Figure 5 The following is a flow chart of the execution status of the pre-charging relay. Figure 5 As shown, the process of the execution state of the pre-charging relay K2 includes:

[0115] Step 1: After receiving the instruction to close the pre-charging relay K2, execute step 2.

[0116] Step 2, determine whether the bus voltage Udc> the set reference value Udc_ref: if so, execute step 3; otherwise return to step 2, that is, if the bus voltage Udc is less than or equal to the set reference value Udc_ref, do not respond to the instruction to close the pre-charge relay K2, and remain in a waiting state.

[0117] Step 3. If the bus voltage Udc>the set reference value Udc_ref, the main control chip controls GPIO2 to enable and output a high level. At this time, the transistor Q2 is not turned on, and the negative pin of the voltage comparison chip U3 (i.e., the operational amplifier U3) is pulled down by the resistor R6. The negative pin voltage of the operational amplifier U3 is less than the reference voltage Uref. Therefore, the operational amplifier U3 outputs a high level. The chip U4 (i.e., the AND gate U4) performs AND logic on the GPIO2 level and the output level of the operational amplifier U3. The AND gate U4 outputs a high level to turn on the transistor Q1, which can control the pre-charge relay K2 to close, and then execute step 4.

[0118] In step 2 and step 3, after receiving the instruction to close the pre-charging relay K2, if it is determined that the bus voltage Udc is relatively small, the instruction is not responded to in order to protect the safety of the vehicle's electricity use. The low bus voltage Udc may be due to: battery power consumption resulting in very low voltage, controller front-end power supply disconnection, other component failures requiring power off, etc. At this time, the pre-charging relay may not respond to the instruction request. When the bus voltage Udc is higher than the set reference value (such as the set reference value Udc_ref), the controller responds to the instruction, controls the pre-charging relay K2 to close, and starts charging.

[0119] Step 4. After the pre-charge relay K2 is closed, the main control chip delays for a time period of T, and then enables the GPIO1 pin to turn on the transistor Q2, and then executes step 5. After the pre-charge relay K2 is closed, the main control chip delays for a time period of T, and then enables the GPIO1 pin to turn on the transistor Q2. At this time, the pre-charge resistor protection circuit is enabled. If the load is abnormal or starts during this period, a large current is generated in the pre-charge circuit, and the negative pin voltage of the operational amplifier U3 is greater than Uref, then the operational amplifier U3 and the AND gate U4 output a low level, which can quickly disconnect the pre-charge relay K2 to protect the pre-charge resistor. According to Figure 4 As shown, a large current will be generated at the moment of charging the bus capacitor, and the charging current will gradually decrease. The function of the pre-charging resistor R1 is to prevent the large current from impacting the bus capacitor and causing damage to the capacitor, but the pre-charging resistor R1 cannot pass a large current for a long time, otherwise it will be severely heated and damaged. After the delay time T = RC, the current has been reduced a lot, and a large current will not appear under normal circumstances. At this time, the pre-charging resistor protection circuit is enabled to ensure that: on the one hand, the large current generated at the moment of charging will not trigger the protection by mistake; on the other hand, the large current generated during the charging process can immediately disconnect the pre-charging relay K2 to protect the pre-charging resistor R1 and the pre-charging circuit.

[0120] In the scheme of the present invention, a voltage detection module (such as a sampling circuit), a voltage comparison module (such as a comparison circuit), and a logic and gate module (such as a control circuit) are added to both ends of the pre-charging resistor of the pre-charging circuit. When controlling the closing of the pre-charging relay, the voltage at both ends of the pre-charging resistor is detected and compared with the reference voltage value set by the hardware, and then the control level obtained by the comparison and the control level output by the control pin of the main chip are ANDed, and the control signal for controlling the closing and disconnection of the pre-charging relay is output. If a large current appears for a long time during the closing stage of the pre-charging relay, the pre-charging relay can be quickly controlled to be turned off through the designed hardware sampling and comparison circuit to avoid damage to the pre-charging resistor and cause failure of the pre-charging circuit, thereby realizing the self-protection function of the pre-charging circuit.

[0121] In some embodiments, the control method of the pre-charging protection device described in the solution of the present invention also includes: a function of controlling the pre-charging process after the pre-charging relay module is closed, see the following exemplary description for details.

[0122] Combine the following Figure 8 The method of the present invention is shown as a flow chart of an embodiment of controlling the pre-charging process after the pre-charging relay module is closed, further illustrating the specific process of controlling the pre-charging process after the pre-charging relay module is closed, including: step S310 to step S330.

[0123] Step S310, after the pre-charging relay module is closed to make the pre-charging circuit work, delay a second set time to determine whether the bus voltage of the high voltage DC system is greater than the real-time voltage of the capacitive load device times the set coefficient:

[0124] Step S320, if yes, control the main relay to close, stop sending the enable signal for enabling the pre-charging relay module, and stop sending the comparison enable signal (i.e., stop sending the enable signal for enabling the comparison unit);

[0125] Step S330, otherwise, initiate a reminder message of a pre-filling timeout fault in the pre-filling circuit, stop sending the enable signal for enabling the pre-filling relay module, and stop sending the comparison enable signal (i.e., stop sending the enable signal for enabling the comparison unit).

[0126] like Figure 5As shown, the process of the execution status of the pre-charging relay K2 also includes: Step 5, detecting the voltage across the pre-charging resistor R1 as the pre-charging voltage. If the pre-charging voltage is greater than 0.9*Udc after the pre-charging relay K2 is closed for a period of time, the main relay K1 is closed, and then the pre-charging relay K2 is disconnected and the transistor Q2 is turned off to complete the normal power-on process; if the pre-charging voltage is less than or equal to 0.9Udc, a pre-charging timeout fault is reported. This fault may be caused by abnormal conditions such as large current in the pre-charging circuit, voltage sampling circuit failure, and disconnection of the DC high voltage power supplied to the controller. Similarly, the pre-charging relay K2 is controlled to disconnect and the transistor Q2 is turned off, and the pre-charging relay K2 can be closed again after waiting for reset.

[0127] In step 5, after closing the pre-charge relay K2 for a period of time, it can be specifically calculated according to the above formula that after 3 to 5 times of RC time, the bus capacitor charging voltage has reached 0.95-0.99 times the bus voltage, and the charging current is already very small. At this time, the main relay K1 is closed, and no damage to the capacitor or relay is caused. Then the pre-charge relay K2 can be disconnected. When the load is started, the large current is passed through the main relay K1. If the voltage obtained by sampling is relatively low within a period of time, a fault may have occurred during the pre-charge process, and a pre-charge timeout fault is reported, and the pre-charge relay K2 is disconnected, and the power is turned on again after restarting. The scheme of the present invention, taking the pre-charging circuit of new energy vehicles as an example, is not limited to this situation, and some other high-voltage DC systems (such as air-conditioning systems, photovoltaic systems, etc.) are also applicable.

[0128] In the scheme of the present invention, the pre-charging resistor is connected in series with the pre-charging relay to detect the voltage across the pre-charging resistor, that is, the voltage across the pre-charging resistor in the pre-charging circuit is sampled. When there is a large current in the pre-charging circuit, the hardware circuit will quickly turn off the pre-charging relay, effectively reducing the damage to the controller; and the time for enabling the pre-charging resistor protection circuit is controlled to effectively prevent false triggering of the protection. Specifically, when the closing instruction of the pre-charging relay is received, if the bus voltage is lower than the preset voltage, the closing of the pre-charging relay will not be responded to; the pre-charging relay will be closed after the bus voltage is higher than the preset voltage, and the pre-charging resistor protection circuit will be enabled after the pre-charging relay is closed for T=RC time. If the load is short-circuited during the pre-charging of the bus capacitor during the closing stage of the pre-charging relay or the load starts to generate a large current, the pre-charging relay can be quickly controlled to be turned off to avoid damage to the pre-charging resistor and cause failure of the pre-charging circuit, thereby realizing the self-protection function of the pre-charging circuit.

[0129] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned pre-charging protection device, for the details not exhaustive in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0130] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0131] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A pre-charge protection device, characterized in that: Capacitive load equipment applied to a high voltage direct current system; the capacitive load equipment comprises a busbar capacitance module, a main circuit and a pre-charging circuit, the main circuit comprises a main relay module, the pre-charging circuit comprises a pre-charging resistor module and a pre-charging relay module; The pre-filling protection device comprises: a sampling unit, a comparison unit, a logic processing unit, and a control unit; wherein the pre-filling protection function of the pre-filling protection device after the pre-filling relay module is closed comprises: The sampling unit is used to obtain the voltage across the high-voltage direct current system when the pre-charging circuit works to charge the bus capacitor module, and record it as the bus voltage of the high-voltage direct current system; The control unit is used to delay for a first set time and send an enable signal for enabling the comparison unit after the pre-filling relay module is closed to make the pre-filling circuit work, which is recorded as a comparison enable signal; The comparison unit is configured to output a protection control signal when receiving the comparison enable signal and when the bus voltage of the high voltage DC system is greater than a reference voltage set by the comparison unit itself; The logic processing unit is used to disconnect the pre-charging relay module based on the protection control signal to protect the pre-charging resistor module and the pre-charging circuit.

2. The pre-filling protection device according to claim 1, characterized in that: in, The sampling unit includes: a differential sampling module, a first operational amplifier module, a current limiting module, and a filtering module; the number of the current limiting modules is two, and the number of the filtering modules is two; wherein, The first connection end and the second connection end of the input end of the differential sampling module are respectively connected to the two ends of the pre-charging resistor module; the first connection end and the second connection end of the output end of the differential sampling module are respectively connected to the in-phase input end and the inverting input end of the first operational amplifier module after passing through a corresponding one of the two current limiting modules; the in-phase input end of the first operational amplifier module is grounded after passing through one of the two filtering modules; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the other of the two filtering modules; the output end of the first operational amplifier module serves as the output end of the sampling unit; and / or, The comparison unit includes: a first switch tube module, a second operational amplifier module, a reference voltage setting module, and a pull-down resistor module; wherein, The control end of the first switch tube module is used as the enable end of the comparison unit to receive the enable signal sent by the control unit to enable the comparison unit; the output end of the sampling unit is connected to the first connection end of the first switch tube module; the second connection end of the first switch tube module is connected to the inverting input end of the second operational amplifier module; the inverting input end of the second operational amplifier module is grounded after passing through the pull-down resistor module; The preset DC power supply is connected to the non-inverting input terminal of the second operational amplifier module after passing through the reference voltage setting module; the output terminal of the second operational amplifier module serves as the output terminal of the comparison unit.

3. The pre-filling protection device according to claim 1 or 2, characterized in that: The logic processing unit includes: a second switch tube module and an AND logic module; wherein, The output end of the comparison unit is connected to the first input end of the AND logic module; the second input end of the AND logic module is used to receive an enable signal sent by the control unit to enable the pre-charge relay module; the output end of the AND logic module is connected to the control end of the second switch tube module; The first connection end of the second switch tube module is connected to a preset DC power supply; the second connection end of the second switch tube module is connected to the control end of the pre-charging relay module.

4. The pre-filling protection device according to any one of claims 1 to 3, characterized in that: The function of the pre-fill protection module controlling the closing of the pre-fill relay before the pre-fill relay module is closed includes: The sampling unit is further used to obtain the voltage across the bus capacitor module when the capacitive load device starts to be powered on, and record it as the real-time voltage of the capacitive load device; The control unit is further configured to, upon receiving a closing instruction of the pre-charging relay module, send an enable signal for enabling the pre-charging relay module, recorded as a pre-charging enable signal, if it is determined that the real-time voltage of the capacitive load device is greater than a set reference value; and The comparison unit is further configured to output a reference control signal based on a reference voltage set by the comparison unit itself when the control unit does not enable the comparison unit itself; The logic processing unit is used to close the pre-charging relay module based on the reference control signal and the pre-charging enable signal to enable the pre-charging circuit to operate.

5. The pre-filling protection device according to any one of claims 1 to 4, characterized in that: The function of the pre-charging protection device to control the pre-charging process after the pre-charging relay module is closed includes: The control unit is further configured to delay a second set time after the pre-charging relay module is closed to enable the pre-charging circuit to operate, and determine whether the bus voltage of the high-voltage direct current system is greater than the real-time voltage of the capacitive load device times the set coefficient: If yes, the main relay is controlled to close, and the enabling signal for enabling the pre-charging relay module and the enabling signal for enabling the comparison unit are stopped; Otherwise, a reminder message of a pre-filling timeout fault in the pre-filling circuit is initiated, and sending of an enable signal for enabling the pre-filling relay module and sending of an enable signal for enabling the comparison unit are stopped.

6. A motor controller, characterized in that: include: A pre-fill protection device as claimed in any one of claims 1 to 5.

7. A vehicle, characterized in that: include: A pre-charge protection device as claimed in any one of claims 1 to 5, or a motor controller as claimed in claim 6.

8. A control method for a pre-filling protection device according to any one of claims 1 to 5, characterized in that: include: When the pre-charging circuit works to charge the bus capacitor module, a voltage across the high-voltage direct current system is obtained, which is recorded as a bus voltage of the high-voltage direct current system; After the pre-filling relay module is closed to make the pre-filling circuit work, a first set time is delayed and an enable signal for comparison is issued, which is recorded as a comparison enable signal; When the comparison enable signal is received, and when the bus voltage of the high voltage direct current system is greater than a preset reference voltage, outputting a protection control signal; Based on the protection control signal, the pre-charging relay module is disconnected to protect the pre-charging resistor module and the pre-charging circuit.

9. The control method of the pre-filling protection device according to claim 8, characterized in that: Also includes: When the capacitive load device starts to be powered on, the voltage across the bus capacitor module is obtained and recorded as the real-time voltage of the capacitive load device; When receiving the closing instruction of the pre-charging relay module, if it is determined that the real-time voltage of the capacitive load device is greater than the set reference value, an enable signal for enabling the pre-charging relay module is issued, which is recorded as a pre-charging enable signal; as well as, outputting a reference control signal based on a preset reference voltage when the comparison enable signal is not received; Based on the reference control signal and the pre-charge enable signal, the pre-charge relay module is closed to enable the pre-charge loop to operate.

10. The control method of the pre-filling protection device according to claim 8 or 9, characterized in that: Also includes: After the pre-charging relay module is closed to make the pre-charging circuit work, a second set time is delayed to determine whether the bus voltage of the high-voltage direct current system is greater than the real-time voltage of the capacitive load device times the set coefficient: If yes, the main relay is controlled to close, and the enabling signal for enabling the pre-charging relay module and the comparison enabling signal are stopped; Otherwise, a reminder message of a pre-filling timeout fault in the pre-filling circuit is initiated, and sending of an enable signal for enabling the pre-filling relay module and sending of the comparison enable signal are stopped.

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