Battery electric engineering vehicle and vehicle-mounted control method and device thereof

Abstract

The present invention discloses a battery electric engineering vehicle and a vehicle-mounted control method and device thereof, wherein the vehicle-mounted control method includes vehicle-mounted discharge control, wherein the vehicle-mounted discharge control includes controlling the pantograph to be lowered, controlling the fast circuit breaker and the second contactor to be closed, the first contactor and the third contactor to be disconnected, and controlling the electric brake module in the traction converter to be in a conducting state, so that the traction battery pack discharges the brake resistor. The present invention does not need to configure additional vehicle-mounted discharge equipment, and in combination with the existing vehicle-mounted charging equipment, the vehicle-mounted charge and discharge balancing function of the traction battery pack can be realized, which greatly reduces the difficulty and workload of engineering vehicle maintenance and saves maintenance costs.

Description

Technical Field

[0001] The present invention belongs to the field of locomotive main and auxiliary circuits and control technology, and in particular relates to a battery electric engineering vehicle and a vehicle-mounted control method and device thereof. Background Art

[0002] Battery-powered engineering vehicles (hereinafter referred to as engineering vehicles) use DC1500V overhead line and traction batteries to power the locomotive, and have the advantages of zero pollution and zero emissions. They gradually replace traditional internal combustion engine engineering vehicles in the field of urban rail transit and gradually become the main traction power model. By the end of 2021, more than 10 cities and more than 20 subway lines in the country have adopted battery-powered engineering vehicles, and the number of such vehicles in the country has reached nearly 200.

[0003] The traction battery pack configured in the engineering vehicle is the power source of the whole vehicle. After the traction battery pack has been used for a period of time (half a year to a year), the characteristics of each battery cell will differ, causing the performance of the whole traction battery pack to decline, mainly the capacity to decline, and in severe cases it can drop to 60-80% of the original design capacity. Therefore, it is necessary to balance the traction battery pack of the whole vehicle regularly. The specific measure is to balance the traction battery pack by three charges and two discharges (i.e., fully charged-discharged according to the standard-fully charged-discharged according to the standard-fully charged)

[0004] At present, engineering vehicles are only equipped with on-board traction battery charging equipment, but no discharging equipment, so it is impossible to discharge the on-board traction battery. For this reason, engineering vehicle users usually need to configure additional ground traction battery charging and discharging equipment (for example, users of subway lines configure ground charging and discharging machines in workshop warehouses), and only after the traction battery is disassembled and hoisted to the ground can it be balanced by three charges and two discharges, and then the traction battery can be installed on the vehicle after completion. This balanced charging and discharging method of traction batteries greatly increases the difficulty and workload of engineering vehicle maintenance, causing great inconvenience, and the configuration of ground charging and discharging equipment is also a huge capital investment. Summary of the invention

[0005] The purpose of the present invention is to provide a battery electric engineering vehicle and its on-board control method and device, so as to solve the problem that the existing battery electric engineering vehicle is only equipped with on-board charging equipment but not equipped with on-board discharging equipment, resulting in the inability to realize the on-board charge and discharge balancing function of the traction battery.

[0006] The present invention solves the above technical problems through the following technical solutions: a vehicle-mounted control method for a battery-powered engineering vehicle, wherein the main and auxiliary circuits of the battery-powered engineering vehicle include a pantograph, a first contactor, a second contactor, a third contactor, a fast circuit breaker, a traction battery pack, an auxiliary inverter, and a traction converter; the auxiliary inverter includes an auxiliary inverter module and a battery charging module, wherein the first end of the auxiliary inverter module is connected to the auxiliary load through a transformer, and the second end thereof is connected to the first end of the battery charging module; the traction converter includes a traction inverter module and an electric brake module. The first end of the traction inverter module is connected to the traction motor, the second end of the traction inverter module is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to the brake resistor; the pantograph, the first contactor, and the fast circuit breaker are connected in sequence; the pantograph is in contact with the overhead wire; the fast circuit breaker is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor is also connected to the negative end of the traction battery through the second contactor; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor;

[0007] The vehicle-mounted control method includes vehicle-mounted discharge control, and the specific implementation process of the vehicle-mounted discharge control includes:

[0008] When the vehicle is stationary and the traction battery pack needs to be discharged on board, the pantograph is controlled to be lowered, the fast circuit breaker and the second contactor are controlled to be closed, the first contactor and the third contactor are controlled to be disconnected, and the electric brake module in the traction inverter is controlled to be in a conducting state, so that the traction battery pack discharges the brake resistor.

[0009] Furthermore, the specific implementation process of the traction battery pack discharging the brake resistor is as follows:

[0010] monitoring the temperature of the brake resistor;

[0011] When the temperature of the braking resistor is higher than the protection temperature thereof, the electric braking module in the traction converter is controlled to be in a cut-off state, so that the traction battery pack stops discharging the braking resistor;

[0012] When the temperature of the braking resistor is lower than the protection temperature thereof, the electric braking module in the traction converter is controlled to be in a conducting state, so that the traction battery pack continues to discharge the braking resistor.

[0013] Furthermore, the specific implementation process of the on-board discharge control also includes:

[0014] monitoring the output voltage of the traction battery pack;

[0015] When the output voltage is lower than its discharge cut-off voltage, the electric brake module in the traction converter is controlled to be in a cut-off state, the traction battery pack is stopped from discharging the brake resistor, and the fast circuit breaker and the second contactor are controlled to be disconnected to complete one discharge.

[0016] Furthermore, the vehicle-mounted control method also includes vehicle-mounted charging control, and the specific implementation process of the vehicle-mounted charging control includes:

[0017] When the vehicle is in a traction state, the first contactor is controlled to be closed and the second contactor is disconnected, or the first contactor is controlled to be disconnected and the second contactor is closed, and the fast circuit breaker and the third contactor are controlled to be closed at the same time. When the traction battery pack needs to be charged on board, the battery charging module is controlled to be in a conducting state, that is, the traction battery pack is charged.

[0018] Furthermore, the vehicle-mounted control method also includes braking control, and the specific implementation process of the braking control includes:

[0019] When the vehicle enters the electric braking condition, the traction inverter module in the traction converter is controlled to stop working, the traction force is cut off, the vehicle enters the coasting state, the traction motor is in the power generation state, and the traction inverter module in the traction converter is controlled to be in the reverse rectification working state, so that the AC power generated by the traction motor is rectified into DC power;

[0020] When the DC voltage is lower than the first set value and the first contactor is closed, or the DC voltage is lower than the second set value and the second contactor is closed, the electric brake module is controlled to be in the cut-off state, and the DC power is fed back to the contact network or the traction battery pack to achieve regenerative braking; otherwise, the electric brake module is controlled to be in the on state, and the DC power is consumed by the braking resistor to achieve resistance braking.

[0021] Preferably, the first set value is DC1750V, and the second set value is DC1200V.

[0022] Based on the same inventive concept, the present invention also provides an on-board control device for a battery electric engineering vehicle, including a main and auxiliary circuit and a control circuit, wherein the main and auxiliary circuits include a pantograph, a first contactor, a second contactor, a third contactor, a fast circuit breaker, a traction battery pack, an auxiliary inverter and a traction converter; the auxiliary inverter includes an auxiliary inverter module and a battery charging module, wherein a first end of the auxiliary inverter module is connected to an auxiliary load through a transformer, and a second end thereof is connected to a first end of the battery charging module; the traction converter includes a traction inverter module and an electric brake module, wherein The first end of the traction inverter module is connected to the traction motor, and the second end thereof is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to the brake resistor; the pantograph, the first contactor, and the fast circuit breaker are connected in sequence; the pantograph is in contact with the overhead wire; the fast circuit breaker is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor is also connected to the negative end of the traction battery through the second contactor; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor;

[0023] The control circuit is used to control the pantograph to be lowered, control the fast circuit breaker and the second contactor to be closed, and the first contactor and the third contactor to be disconnected when the vehicle is in a stationary state and the traction battery pack needs to be discharged on board, and control the electric brake module in the traction inverter to be in a conducting state, so that the traction battery pack discharges the brake resistor.

[0024] Furthermore, the control circuit is also used to control the first contactor to close and the second contactor to open, or to control the first contactor to open and the second contactor to close, and to control the fast circuit breaker and the third contactor to close when the vehicle is in a traction state, and to control the battery charging module to be in a conducting state when the traction battery pack needs to be charged on board, so as to realize charging of the traction battery pack.

[0025] Furthermore, there are two traction converters.

[0026] Furthermore, a pre-charging module is provided between the fast circuit breaker and the first end of the electric brake module, between the fast circuit breaker and the second end of the auxiliary inverter module and the first end of the battery charging module, and the pre-charging module includes a working contactor, a pre-charging contactor and a pre-charging resistor; the pre-charging contactor contacts are connected in series with the pre-charging resistor and then in parallel with the working contactor contacts.

[0027] Based on the same inventive concept, the present invention also provides a battery electric engineering vehicle, including the battery electric engineering vehicle on-board control device as described above.

[0028] Beneficial Effects

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The present invention provides a battery electric engineering vehicle and an on-board control method and device thereof. Based on the existing main and auxiliary circuits, the traction battery pack discharges the brake resistor by controlling the actions of the contactor, the fast circuit breaker and the electric brake module in the main and auxiliary circuits, thereby realizing the on-board discharge function of the traction battery pack. There is no need to configure additional on-board discharge equipment. In addition, with the existing on-board charging equipment, the on-board charge and discharge balancing function of the traction battery pack can be realized, which greatly reduces the difficulty and workload of engineering vehicle maintenance and saves maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is a main and auxiliary circuit diagram of a battery electric engineering vehicle in an embodiment of the present invention;

[0033] Figure 2 It is a flow chart of on-board discharge control of a battery electric engineering vehicle in an embodiment of the present invention.

[0034] Among them, 1-electric brake module, 2-traction inverter module, 3-auxiliary inverter module, 4-battery charging module, 5-pre-charging module, 6-grounding device. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the drawings in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0036] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0037] Embodiment 1

[0038] On the basis of the existing main and auxiliary circuits of the battery electric engineering vehicle, by controlling the actions of the contactors, fast circuit breakers and electric brake modules in the main and auxiliary circuits, the traction battery pack discharges to the brake resistor, thereby realizing the on-board discharge function of the traction battery pack. There is no need to configure additional on-board discharge equipment, thereby realizing the on-board charge and discharge balancing function of the traction battery.

[0039] like Figure 1 As shown in the main and auxiliary circuit schematic diagram, the main and auxiliary circuits include a pantograph, a first contactor K01, a second contactor K02, a third contactor K03, a fast circuit breaker HSCB, a traction battery pack, an auxiliary inverter and a traction converter; the auxiliary inverter includes an auxiliary inverter module and a battery charging module, the first end of the auxiliary inverter module is connected to the auxiliary load through a transformer, and the second end thereof is connected to the first end of the battery charging module; the traction converter includes a traction inverter module and an electric brake module, the first end of the traction inverter module is connected to the traction motor, the second end thereof is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to the brake resistor R; the pantograph, the first contactor K01 and the fast circuit breaker HSCB are connected in sequence; the pantograph is in contact with the overhead line; the fast circuit breaker HSCB is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor K01 is also connected to the negative end of the traction battery through the second contactor K02; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor K03.

[0040] Based on the above main and auxiliary circuits, an on-board control method for a battery-powered engineering vehicle provided by an embodiment of the present invention includes on-board discharge control, on-board charging control, and braking control. Figure 2 As shown in the figure, the specific implementation process of on-board discharge control is:

[0041] When the vehicle is stationary (vehicle speed is zero) and the traction battery pack needs to be discharged on board, the pantograph is controlled to be lowered, the fast circuit breaker HSCB and the second contactor K02 are controlled to be closed, the first contactor K01 and the third contactor K03 are controlled to be disconnected, and the electric brake module in the traction inverter is controlled to be in the on state. The traction battery pack is connected to the brake circuit through the second contactor K02, the fast circuit breaker HSCB, and the electric brake module, so that the traction battery pack discharges the brake resistor R.

[0042] In a specific embodiment of the present invention, during the process of the traction battery pack discharging the brake resistor R, the temperature of the brake resistor R is also monitored; when the temperature of the brake resistor R is higher than the protection temperature of the brake resistor R, the electric brake module in the traction converter is controlled to be in a cut-off state, so that the traction battery pack stops discharging the brake resistor R; when the temperature of the brake resistor R is lower than the protection temperature of the brake resistor R, the electric brake module in the traction converter is controlled to be in a conducting state, so that the traction battery pack continues to discharge the brake resistor R. By monitoring the temperature of the brake resistor R during the discharge process, overheating damage of the brake resistor R is avoided.

[0043] In a specific embodiment of the present invention, during the process of the traction battery pack discharging the brake resistor R, the voltage sensor B02 is also used to monitor the output voltage of the traction battery pack; when the output voltage of the traction battery pack is lower than the discharge cut-off voltage of the traction battery pack, the electric brake module in the traction converter is controlled to be in the cut-off state, the traction battery pack is stopped from discharging the brake resistor R, and the fast circuit breaker HSCB and the second contactor K02 are controlled to be disconnected, completing one discharge. By monitoring the output voltage of the traction battery pack during the discharge process, the over-discharge problem of the traction battery pack is avoided.

[0044] In a specific embodiment of the present invention, the specific implementation process of the vehicle-mounted discharge control is:

[0045] When the vehicle is in traction state (vehicle speed is not zero and in running state) and in contact network power supply mode, the first contactor K01 is controlled to be closed and the second contactor K02 is disconnected (i.e. contact network power supply), and at the same time, the fast circuit breaker HSCB and the third contactor K03 are controlled to be closed, so that the charging path of the traction battery pack is unobstructed; when the traction battery pack needs to be charged on board, the battery charging module is controlled to be in the on state, that is, the traction battery pack is charged.

[0046] In a specific embodiment of the present invention, the specific implementation process of the vehicle-mounted discharge control is:

[0047] When the vehicle is in traction state (vehicle speed is not zero, in running state) and traction battery power supply mode, the first contactor K01 is controlled to be disconnected and the second contactor K02 is controlled to be closed (i.e. traction battery power supply), and at the same time, the fast circuit breaker HSCB and the third contactor K03 are controlled to be closed, so that the charging path of the traction battery pack is unblocked; when the traction battery pack needs to be charged on board, the battery charging module is controlled to be in the on state, that is, the traction battery pack is charged.

[0048] In a specific embodiment of the present invention, the specific implementation process of the braking control is:

[0049] When the vehicle enters the electric braking condition, the traction inverter module in the traction inverter is controlled to stop working and the traction force is cut off. At the same time, the vehicle enters the coasting state, the traction motor is still working and the traction motor is in the power generation state. The traction inverter module in the traction inverter is controlled to be in the reverse rectification working state, so that the AC power generated by the traction motor is rectified into DC power.

[0050] When the DC voltage detected by the voltage sensor B03 is lower than the first set value and the first contactor K01 is closed, or the DC voltage detected by the voltage sensor B03 is lower than the second set value and the second contactor K02 is closed, the electric brake module is controlled to be in the cut-off state, and the DC power is fed back to the overhead contact network or the traction battery pack to achieve regenerative braking; otherwise, the electric brake module is controlled to be in the on state, and the DC power is consumed by the braking resistor R to achieve resistance braking. In this embodiment, the first set value is DC1750V, and the second set value is DC1200V.

[0051] Embodiment 2

[0052] The embodiment of the present invention also provides a battery electric engineering vehicle on-board control device, including a main and auxiliary circuit and a control circuit, such as Figure 1 As shown, the main and auxiliary circuits include a pantograph, a first contactor K01, a second contactor K02, a third contactor K03, a fast circuit breaker HSCB, a traction battery pack, an auxiliary inverter and a traction converter; the auxiliary inverter includes an auxiliary inverter module and a battery charging module, the first end of the auxiliary inverter module is connected to the auxiliary load through a transformer, and the second end thereof is connected to the first end of the battery charging module; the traction converter includes a traction inverter module and an electric brake module, the first end of the traction inverter module is connected to the traction motor, the second end thereof is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to the brake resistor R; the pantograph, the first contactor K01 and the fast circuit breaker HSCB are connected in sequence; the pantograph is in contact with the overhead line; the fast circuit breaker HSCB is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor K01 is also connected to the negative end of the traction battery through the second contactor K02; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor K03.

[0053] The control circuit is used to control the pantograph to be lowered, the fast circuit breaker HSCB and the second contactor K02 to be closed, the first contactor K01 and the third contactor K03 to be disconnected, and the electric brake module in the traction converter to be in the on state, so that the traction battery pack discharges the brake resistor R when the vehicle is stationary and the traction battery pack needs to be discharged on board.

[0054] During the process of the traction battery pack discharging the brake resistor R, the control circuit also monitors the temperature of the brake resistor R; when the temperature of the brake resistor R is higher than the protection temperature of the brake resistor R, the electric brake module in the traction converter is controlled to be in the cut-off state, so that the traction battery pack stops discharging the brake resistor R; when the temperature of the brake resistor R is lower than the protection temperature of the brake resistor R, the electric brake module in the traction converter is controlled to be in the on state, so that the traction battery pack continues to discharge the brake resistor R. The control circuit also uses the voltage sensor B02 to monitor the output voltage of the traction battery pack; when the output voltage of the traction battery pack is lower than the discharge cut-off voltage of the traction battery pack, the electric brake module in the traction converter is controlled to be in the cut-off state, the traction battery pack stops discharging the brake resistor R, and the fast circuit breaker HSCB and the second contactor K02 are controlled to be disconnected to complete one discharge.

[0055] The control circuit is also used for controlling the first contactor K01 to close and the second contactor K02 to open, or controlling the first contactor K01 to open and the second contactor K02 to close when the vehicle is in a traction state, and controlling the high-speed circuit breaker HSCB and the third contactor K03 to close at the same time, and controlling the battery charging module to be in a conducting state when the traction battery pack needs to be charged on board, that is, to realize charging of the traction battery pack.

[0056] The control circuit is also used to control the traction inverter module in the traction inverter to stop working and cut off the traction force when the vehicle enters the electric braking condition. At the same time, the vehicle enters the coasting state, the traction motor is still working, and the traction motor is in the power generation state. The traction inverter module in the traction inverter is controlled to be in the reverse rectification working state, so that the AC power generated by the traction motor is rectified into DC power.

[0057] When the DC voltage detected by the voltage sensor B03 is lower than the first set value and the first contactor K01 is closed, or the DC voltage detected by the voltage sensor B03 is lower than the second set value and the second contactor K02 is closed, the electric brake module is controlled to be in the cut-off state, and the DC power is fed back to the overhead contact network or the traction battery pack to achieve regenerative braking; otherwise, the electric brake module is controlled to be in the on state, and the DC power is consumed by the braking resistor R to achieve resistance braking. In this embodiment, the first set value is DC1750V, and the second set value is DC1200V.

[0058] In a specific implementation of the present invention, there are multiple traction converters. In this embodiment, there are two traction converters.

[0059] In a specific embodiment of the present invention, a pre-charging module is provided between the fast circuit breaker HSCB and the first end of the electric brake module, between the fast circuit breaker HSCB and the second end of the auxiliary inverter module and the first end of the battery charging module, and the pre-charging module includes a working contactor, a pre-charging contactor and a pre-charging resistor; the pre-charging contactor contacts are connected in series with the pre-charging resistor and then in parallel with the working contactor contacts.

[0060] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A method for controlling a battery-powered engineering vehicle on a vehicle, wherein the main and auxiliary circuits of the battery-powered engineering vehicle include a pantograph, a first contactor, a second contactor, a third contactor, a fast circuit breaker, a traction battery pack, an auxiliary inverter, and a traction converter; the auxiliary inverter includes an auxiliary inverter module and a battery charging module, wherein the first end of the auxiliary inverter module is connected to an auxiliary load through a transformer, and the second end thereof is connected to the first end of the battery charging module; the traction converter includes a traction inverter module and an electric brake module, wherein the first end of the traction inverter module is connected to a traction motor, the second end thereof is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to a brake resistor; the pantograph, the first contactor, and the fast circuit breaker are connected in sequence; the pantograph contacts the overhead line; the fast circuit breaker is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor is also connected to the negative end of the traction battery through the second contactor; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor; It is characterized in that The vehicle-mounted control method includes vehicle-mounted discharge control, and the specific implementation process of the vehicle-mounted discharge control includes: When the vehicle is stationary and the traction battery pack needs to be discharged on board, the pantograph is controlled to be lowered, the fast circuit breaker and the second contactor are controlled to be closed, the first contactor and the third contactor are controlled to be disconnected, and the electric brake module in the traction inverter is controlled to be in a conducting state, so that the traction battery pack discharges the brake resistor.

2. The on-board control method of a battery-powered engineering vehicle according to claim 1, characterized in that: The specific implementation process of the traction battery pack discharging the brake resistor is as follows: monitoring the temperature of the brake resistor; When the temperature of the braking resistor is higher than the protection temperature thereof, the electric braking module in the traction converter is controlled to be in a cut-off state, so that the traction battery pack stops discharging the braking resistor; When the temperature of the braking resistor is lower than the protection temperature thereof, the electric braking module in the traction converter is controlled to be in a conducting state, so that the traction battery pack continues to discharge the braking resistor.

3. The on-board control method of a battery-powered engineering vehicle according to claim 1 or 2, characterized in that: The specific implementation process of the on-board discharge control also includes: monitoring the output voltage of the traction battery pack; When the output voltage is lower than its discharge cut-off voltage, the electric brake module in the traction converter is controlled to be in a cut-off state, the traction battery pack is stopped from discharging the brake resistor, and the fast circuit breaker and the second contactor are controlled to be disconnected to complete one discharge.

4. The on-board control method of a battery-powered engineering vehicle according to claim 1, characterized in that: It also includes on-board charging control, and the specific implementation process of the on-board charging control includes: When the vehicle is in a traction state, the first contactor is controlled to be closed and the second contactor is disconnected, or the first contactor is controlled to be disconnected and the second contactor is closed, and the fast circuit breaker and the third contactor are controlled to be closed at the same time. When the traction battery pack needs to be charged on board, the battery charging module is controlled to be in a conducting state, that is, the traction battery pack is charged.

5. The on-board control method of a battery-powered engineering vehicle according to claim 1, characterized in that: It also includes braking control, and the specific implementation process of the braking control includes: When the vehicle enters the electric braking condition, the traction inverter module in the traction converter is controlled to stop working, the traction force is cut off, the vehicle enters the coasting state, the traction motor is in the power generation state, and the traction inverter module in the traction converter is controlled to be in the reverse rectification working state, so that the AC power generated by the traction motor is rectified into DC power; When the DC voltage is lower than the first set value and the first contactor is closed, or the DC voltage is lower than the second set value and the second contactor is closed, the electric brake module is controlled to be in the cut-off state, and the DC power is fed back to the contact network or the traction battery pack to achieve regenerative braking; otherwise, the electric brake module is controlled to be in the on state, and the DC power is consumed by the braking resistor to achieve resistance braking.

6. The on-board control method of a battery-powered engineering vehicle according to claim 5, characterized in that: The first setting value is DC1750V, and the second setting value is DC1200V.

7. A vehicle-mounted control device for a battery electric engineering vehicle, comprising a main and auxiliary circuit and a control circuit, wherein the main and auxiliary circuits comprise a pantograph, a first contactor, a second contactor, a third contactor, a fast circuit breaker, a traction battery pack, an auxiliary inverter and a traction converter; the auxiliary inverter comprises an auxiliary inverter module and a battery charging module, wherein the first end of the auxiliary inverter module is connected to the auxiliary load through a transformer, and the second end thereof is connected to the first end of the battery charging module; the traction converter comprises a traction inverter module and an electric brake module, wherein the first end of the traction inverter module is connected to the traction motor, the second end thereof is connected to the first end of the electric brake module, and the second end of the electric brake module is connected to a brake resistor; the pantograph, the first contactor and the fast circuit breaker are connected in sequence; the pantograph contacts the overhead line; the fast circuit breaker is also connected to the first end of the electric brake module and the first end of the battery charging module; the first contactor is also connected to the negative end of the traction battery through the second contactor; the positive end of the traction battery pack is also connected to the second end of the battery charging module through the third contactor; the characteristic: The control circuit is used to control the pantograph to be lowered, control the fast circuit breaker and the second contactor to be closed, and the first contactor and the third contactor to be disconnected when the vehicle is in a stationary state and the traction battery pack needs to be discharged on board, and control the electric brake module in the traction inverter to be in a conducting state, so that the traction battery pack discharges the brake resistor.

8. The on-board control device for a battery-powered engineering vehicle according to claim 7, characterized in that: The control circuit is also used to control the first contactor to close and the second contactor to open, or to control the first contactor to open and the second contactor to close when the vehicle is in a traction state, and to control the fast circuit breaker and the third contactor to close at the same time, and to control the battery charging module to be in a conducting state when the traction battery pack needs to be charged on board, that is, to realize charging of the traction battery pack.

9. The on-board control device for a battery-powered engineering vehicle according to claim 7 or 8, characterized in that: There are two traction converters.

10. The on-board control device for a battery-powered engineering vehicle according to claim 7 or 8, characterized in that: A pre-charging module is provided between the fast circuit breaker and the first end of the electric brake module, between the fast circuit breaker and the second end of the auxiliary inverter module and the first end of the battery charging module, and the pre-charging module includes a working contactor, a pre-charging contactor and a pre-charging resistor; the pre-charging contactor contacts are connected in series with the pre-charging resistor and then in parallel with the working contactor contacts.

11. A battery electric engineering vehicle, characterized in that: It comprises the on-board control device of a battery electric engineering vehicle as described in any one of claims 7 to 10.

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