CN116461330A - Control system for downhill working condition and overhead working truck - Google Patents

Control system for downhill working condition and overhead working truck Download PDF

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Publication number
CN116461330A
CN116461330A CN202211090792.7A CN202211090792A CN116461330A CN 116461330 A CN116461330 A CN 116461330A CN 202211090792 A CN202211090792 A CN 202211090792A CN 116461330 A CN116461330 A CN 116461330A
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CN
China
Prior art keywords
circuit
voltage
driver
controlling
energy
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Pending
Application number
CN202211090792.7A
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Chinese (zh)
Inventor
张斌
朱后
熊路
杨存祥
杨煜
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Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd
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Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd filed Critical Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd
Priority to CN202211090792.7A priority Critical patent/CN116461330A/en
Priority to PCT/CN2023/093829 priority patent/WO2024051201A1/en
Publication of CN116461330A publication Critical patent/CN116461330A/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0076—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0084—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to control modules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/10—Dynamic electric regenerative braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/10—Dynamic electric regenerative braking
    • B60L7/18—Controlling the braking effect
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/20—Braking by supplying regenerated power to the prime mover of vehicles comprising engine-driven generators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F11/00—Lifting devices specially adapted for particular uses not otherwise provided for
    • B66F11/04—Lifting devices specially adapted for particular uses not otherwise provided for for movable platforms or cabins, e.g. on vehicles, permitting workmen to place themselves in any desired position for carrying out required operations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Structural Engineering (AREA)
  • Geology (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention relates to the technical field of engineering machinery, and discloses a control system for downhill working conditions and an overhead working truck. The control system includes: an energy consumer; a first switching device; an energy storage; a second switching device; and a control device for: when power is on, the second switching device is controlled to conduct a circuit of the energy accumulator so as to precharge the energy accumulator; when the voltage of the direct current bus is equal to or greater than a first preset voltage, controlling the first switching device to conduct a circuit of the energy consumer so as to capture feedback current; and when the voltage is less than or equal to a second preset voltage, controlling the second switching device to conduct the circuit of the energy accumulator so as to supply power for the driver. According to the intervention control strategy, the accumulator is pre-charged when the power-on is performed, the feedback current is captured when the stall risk exists so as to reduce the feedback voltage of the driver, and the driver is powered by the pre-charge energy when the vehicle speed is reduced, so that the braking moment can be prevented from being reduced, the occurrence of the downslope stall risk is effectively restrained, and the stable parking is realized.

Description

Control system for downhill working condition and overhead working truck
Technical Field
The invention relates to the technical field of engineering machinery, in particular to a control system for downhill working conditions and an overhead working truck.
Background
Electrically driven overhead vehicles (self-propelled) typically have no service brakes, and both deceleration and stopping rely on energy-regenerative braking technology, either electromagnetic or hydraulic braking. This braking mode presents a risk: on downhill slopes, if the regenerative braking voltage exceeds the protection voltage of the drive, the braking torque is limited (i.e. the strength of the regenerative braking is reduced), so that the aerial vehicle is at risk of stalling. At this time, if the vehicle is parked by the emergency stop switch, the parking brake can directly band-type brake to force the aerial working vehicle to slide. High-speed band-type brakes on one hand have great damage to the brakes, and on the other hand the braking distance may become longer. And, even after the vehicle speed is reduced, the dc bus voltage of the driver may be lower than the minimum operating voltage of the driver, thereby causing direct band-type braking of the parking brake, which may have a great degree of damage to the parking brake.
Disclosure of Invention
The invention aims to provide a control system for downhill working conditions and an overhead working truck, which can intervene in a control strategy when the voltage of a direct current bus exceeds a first preset voltage (for example, a certain voltage smaller than the protection voltage of a driver) (namely, before the occurrence of downhill overspeed), reduce the voltage of the direct current bus of the driver by capturing feedback current, thereby avoiding the reduction of braking torque, effectively inhibiting the occurrence of downhill stall risk, and can supply power to the driver through pre-charged electric energy when the voltage of the direct current bus is lower than a second preset voltage (for example, a certain voltage larger than the minimum working voltage of the driver) so as to realize smooth stopping.
To achieve the above object, a first aspect of the present invention provides a control system for a downhill operation, the control system including: the voltage detection device is used for detecting the direct current bus voltage of the driver; the energy consumption device is used for capturing feedback current conveyed by the driver; the first switching device is used for conducting a first circuit where the energy consumer is located; an energy storage; a second switching device for switching on a second circuit in which the energy storage device is located; and control means for performing the following operations: at power up, turning on the second circuit by controlling the second switching device to precharge the energy storage by the battery; under the condition that the voltage of the direct current bus is equal to or greater than a first preset voltage, the first circuit is conducted by controlling the first switching device so as to capture the feedback current by the energy consumer; and under the condition that the voltage of the direct current bus is smaller than or equal to a second preset voltage, the second circuit is conducted by controlling the second switching device to supply power to the driver by the energy accumulator, wherein the first preset voltage is larger than the second preset voltage.
Preferably, the first preset voltage is smaller than a protection voltage of the driver.
Preferably, the second preset voltage is greater than a minimum operating voltage of the driver.
Preferably, the first switching device is a first high frequency switch.
Preferably, the control means for conducting the first circuit by controlling the first switching means comprises: switching on the first circuit by controlling the duty cycle of the first high frequency switch to control the speed at which the feedback current is captured by the consumer, and in the case where the second switching means is a second high frequency switch, the control means for switching on the second circuit by controlling the second switching means to precharge the energy storage by the battery comprises: the second circuit is turned on by controlling the duty cycle of the second high frequency switch to control the rate at which the accumulator is precharged by the battery.
Preferably, in the case where the second switching device includes a first contactor, a resistor, and a second contactor, the second circuit includes: the first sub-circuit is formed by connecting the first contactor and the resistor in series; and a second sub-circuit in which the second contactor is located, wherein both the first contactor and the resistor are connected in parallel with the second contactor, and accordingly, the control means for turning on the second circuit by controlling the second switching means to precharge the energy storage by the battery includes: switching on the first sub-circuit by controlling the first contactor to close and the second contactor to open to precharge the energy storage by the battery, and the control means for switching on the second circuit by controlling the second switching means to supply the driver with power by the energy storage comprises: the second sub-circuit is turned on by controlling the first contactor to open and the second contactor to close to power the driver by the energy storage.
Preferably, the energy storage is a capacitor or a battery.
Preferably, the energy consumer is a resistor.
Through the technical scheme, the circuit of the energy accumulator is conducted to precharge the energy accumulator when the power is on, then the circuit of the energy consumer is conducted to capture feedback current by the energy consumer under the condition that the voltage of the direct current bus is equal to or greater than a first preset voltage, and then the circuit of the energy accumulator is conducted to supply power to the driver by the energy accumulator under the condition that the voltage of the direct current bus is less than or equal to a second preset voltage. Therefore, the invention can intervene in the control strategy when the voltage of the direct current bus exceeds a first preset voltage (for example, a certain voltage smaller than the protection voltage of the driver) (i.e. before the occurrence of downhill overspeed), and the direct current bus voltage of the driver is reduced by capturing the feedback current, so that the braking torque is prevented from becoming smaller, the occurrence of the risk of downhill stall is effectively restrained, and the driver can be powered by the pre-charged electric energy when the voltage of the direct current bus is lower than a second preset voltage (for example, a certain voltage larger than the minimum working voltage of the driver), so that smooth parking is realized.
A second aspect of the present invention provides an aerial work vehicle comprising: the control system is used for downhill working conditions.
Preferably, the aerial vehicle further comprises: a parking brake; and the driver is used for controlling the parking brake to brake under the condition that the rotating speed of the motor is smaller than the preset rotating speed.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention. In the drawings:
FIG. 1 is a schematic illustration of a travel drive system including a control system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a control system for downhill operating conditions provided in accordance with an embodiment of the present invention;
FIG. 3 is a schematic diagram of a control system for downhill operating conditions provided in accordance with an embodiment of the present invention; and
FIG. 4 is a schematic diagram of a control system for downhill operation according to an embodiment of the present invention.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
Before describing the embodiments of the present invention, two concepts will be briefly described.
Regenerative braking: when the electric vehicle is braked, the (walking) motor can be controlled to operate as a generator, so that kinetic energy or potential energy of the vehicle is converted into electric energy and stored in the energy storage module.
Feedback current: during regenerative braking, the drive converts the electrical energy generated by the (travelling) motor into electrical current, known as feedback current, that is available to the energy storage module or other energy consuming components.
FIG. 2 is a schematic diagram of a control system (i.e., safety protection device) for downhill operation according to one embodiment of the present invention. As shown in fig. 2, the control system may include: voltage detection means 10 for detecting a dc bus voltage of the driver; an energy consumer 20 for capturing the feedback current delivered by the driver; a first switching device 30 for conducting a first circuit in which the energy consumer 20 is located; an accumulator 22; a second switching device 50 for conducting a second circuit in which the energy storage device is located; and a control device 40.
When the overhead working truck descends, the motor works in a generator state to keep the speed of the truck unchanged, and at the moment, the driver can generate relatively high feedback electromotive force. Normally, the driver charges the battery, and the feedback electromotive force does not exceed the driver protection voltage.
The inventor researches and discovers that if the battery cannot be charged (the battery is full, the battery power Map (Map) is limited, the line is faulty, the Battery Management System (BMS) is faulty, etc.) during the operation of the aerial working vehicle, the feedback electromotive force can rapidly reach the driver protection voltage. In order to avoid the power electronics being destroyed by high pressure, the driver reduces the strength of the feedback brake, resulting in insufficient braking torque, possibly faster and faster vehicle speeds, and the equipment is at risk of runaway. If the operator is at this moment slowed down by the speed control handle, the driver can control the parking brake to brake directly after a certain time (usually 5S) because the feedback braking strength of the driver is limited and cannot achieve the speed reduction effect. If the operator parks through the scram switch at this moment, the parking brake can directly band-type brake, forces equipment to slide. Both cases force the parking brake to brake at high band-type brake speeds. The high-speed band-type brake braking mode has larger damage to the brake, so that the risk of incapability of parking on a slope exists in the overhead working truck; on the other hand, the braking distance may be long due to sliding, lateral stability is poor, and the overhead working truck is at risk of collision and sideslip.
For example, when going downhill, the battery system may not be able to supply power to the drive 2 and the motor 100 nor to charge the battery system. At this time, as shown in fig. 1, the Vehicle Controller (VCU) 90 and the Battery Management System (BMS) powered by the battery 110 still can work normally, and after receiving the state information provided by the BMS and performing fault judgment, the VCU 90 sends out a parking instruction and warning information, so as to control the relay K1 enabled by the driver 2 to be still in a closed state, thereby, the motor 100 enters a feedback braking state from an electric state, and the electric energy generated by the feedback braking can maintain the normal work of the driver 2 and is far greater than the energy consumption required by the normal work of the driver 2. The dc bus voltage of the drive 2 may rise rapidly (i.e. the vehicle may stall downhill) due to the inability to charge the battery.
Therefore, during the operation of the overhead working truck, the dc bus voltage of the driver may be raised, either due to the full battery power, the limitation of the battery power Map (Map), or the battery failure, and thus the vehicle may stall downhill.
As shown in fig. 3, the first switching device 30 may be a first high frequency switch 31. In particular, the first high frequency switch 31 may be a field effect transistor (i.e., moS transistor).
The voltage detection device 10 may be a voltmeter 11, as shown in fig. 3.
The control device 40 is a Central Processing Unit (CPU) 41, as shown in fig. 3.
The control device 40 is configured to perform the following operations: at power up, the second circuit is turned on by controlling the second switching device 50 to precharge the energy storage by the battery; the first circuit is turned on by controlling the first switching device 30 to capture the feedback current by the energy consumer 20 when the dc bus voltage is equal to or greater than a first preset voltage, and the second circuit is turned on by controlling the second switching device to supply power to the driver by the energy store when the dc bus voltage is less than or equal to a second preset voltage.
Wherein the first preset voltage is greater than the second preset voltage. Specifically, the first preset voltage is smaller than the protection voltage of the driver 2. If the protection voltage of the driver is 100V, the first preset voltage may be set to be less than 100V (e.g., the first preset voltage is 95V).
The second preset voltage is greater than the minimum operating voltage of the driver 2. In practical applications, the second preset voltage may be set reasonably according to specific situations, and may be slightly greater than the minimum operating voltage (i.e., the minimum voltage when the driver operates normally).
Wherein the control means for turning on the first circuit by controlling the first switching means comprises: the first circuit is turned on by controlling a duty cycle of the first high frequency switch to control a speed at which the feedback current is captured by the energy consumer.
In one embodiment, the energy consumer 20 may be a resistor 25 (shown in fig. 4) or the like, and the energy storage may be a capacitor or a battery.
Specifically, taking the energy consumer 20 as the resistor 25 (as shown in fig. 3) as an example, when the dc bus voltage displayed by the voltmeter 11 is equal to or greater than the first preset voltage (for example, 95V), that is, there is a stall risk, the CPU 41 controls the duty ratio of the first high-frequency switch 31 to turn on the circuit where the resistor 25 is located, so as to control the speed at which the resistor 25 consumes the feedback braking energy, thereby controlling the feedback energy absorbed by the resistor, and further stabilizing the dc bus voltage (i.e., the feedback voltage) to prevent the dc bus voltage from exceeding the protection voltage. At this time, since the driver does not limit the strength of the feedback brake, the corresponding vehicle speed is slower and slower, thereby avoiding the risk of stall.
When the electric automobile stalls downhill, the change of gravitational potential energy of the downhill is absorbed through a mechanical brake, but the aerial working automobile does not have the mechanical brake and can only be absorbed by depending on battery charging. The absorption mode of the energy dissipater designed by the scheme solves the problem that the battery system fails and the like cannot be absorbed. By means of stabilizing the direct-current bus voltage, the problem that a driver loses power due to the fact that a battery system is in fault and the like is solved, and overvoltage alarm of the driver caused by too high feedback braking electromotive force is prevented.
That is, in the present embodiment, if no energy storage device (such as an energy storage capacitor) is present, when the dc bus voltage displayed by the voltmeter 11 is equal to or greater than the first preset voltage (i.e., there is a stall risk), the energy consumption resistor consumes the feedback braking energy, so that the dc bus voltage (i.e., the feedback voltage) of the driver can be controlled to be lower than the protection voltage of the driver. At this time, since the actuator does not limit the intensity of the feedback brake, the speed of the overhead working truck can be controlled more and more slowly. However, after the dc bus voltage decreases (i.e., the vehicle speed decreases), the dc bus voltage may be lower than the minimum operating voltage of the driver, thereby causing the parking brake to directly band-brake, which may have some degree of damage to the parking brake.
In view of the above-mentioned drawbacks, an energy storage device and a corresponding circuit are added in the present embodiment to precharge the energy storage device at power-up. Therefore, after the voltage of the direct-current bus is reduced (namely the vehicle speed is reduced), the energy pre-charged by the energy accumulator is used for supplying power to the driver, so that the direct band-type brake of the parking brake controlled by the driver is avoided.
The energy storage 22 may be a capacitor 24 or a battery.
In the case where the second switching means is a second high frequency switch, the control means for turning on the second circuit by controlling the second switching means to precharge the energy storage by the battery includes: the second circuit is turned on by controlling the duty cycle of the second high frequency switch to control the rate at which the accumulator is precharged by the battery.
In an embodiment, the second switching device 50 may be a second high frequency switch 33 or a contactor (as shown in fig. 3). In particular, the second high frequency switch 33 may be a field effect transistor (i.e., moS transistor).
Specifically, taking the accumulator 22 as the capacitor 24 as an example, in the case of power-up, the CPU 41 controls the duty ratio of the second high-frequency switch 33 to turn on the circuit in which it is located, so as to precharge the capacitor 22 by the battery. Then, when the dc bus voltage displayed by the voltmeter 11 is equal to or greater than the first preset voltage (i.e., there is a stall risk), the energy consumption resistor consumes the feedback braking energy, so that the dc bus voltage (i.e., the feedback voltage) of the driver can be controlled to be lower than the protection voltage of the driver. At this time, since the actuator does not limit the intensity of the feedback brake, the speed of the overhead working truck can be controlled more and more slowly. Therefore, in the case that the dc bus voltage shown in the voltmeter 11 is less than or equal to the second preset voltage (i.e., the feedback voltage is close to the minimum operating voltage of the driver), the CPU 41 controls the second high-frequency switch 33 (which is equivalent to a contactor) to turn on the circuit where it is located, so that the capacitor 24 supplies power to the driver 2 (as shown in fig. 3), and thus, the capacitor 22 can provide an auxiliary power source for the driver 2 to complete the braking process (especially when the power system is powered off). However, if the energy absorbed by the capacitor is insufficient, the voltage is reduced (i.e. the vehicle speed is reduced), and then serious undervoltage alarm of the driver may be caused, and the parking brake can be used for braking by the band-type brake directly.
That is, the CPU 41 controls the duty ratio of the second high-frequency switch 33 at the time of power-up to complete the precharge of the energy storage capacitor 24. The function of the priming is to provide the drive 2 with backup energy to complete the deceleration process. When stall risk exists, the energy consumption resistor 25 still absorbs feedback braking energy to stabilize the DC bus voltage. And after the voltage is reduced, the CPU controls the high-frequency switch to control the energy storage capacitor 24 to supply power for the driver, so that the corresponding vehicle speed can be reduced smoothly. When the rotational speed of the motor 100 is below a certain value (e.g., 30 rpm), the parking brake band-type brake.
In the case where the second switching device may include the first contactor 34, the resistor 60, and the second contactor 35, the second circuit may include: a first sub-circuit in which the first contactor 34 is connected in series with the resistor 60; and a second sub-circuit in which the second contactor 35 is located. Wherein both the first contactor 34 and the resistor 60 are connected in parallel with the second contactor 35.
Accordingly, the control means 40 (e.g. CPU 41) for switching on the second circuit by controlling the second switching means to precharge the energy storage by the battery comprises: switching on the first sub-circuit by controlling the first contactor 34 to close and the second contactor 35 to open to precharge the energy storage by the battery, and the control means 40 (e.g., CPU 41) for switching on the second circuit by controlling the second switching means to supply the driver with power by the energy storage comprises: the second sub-circuit is turned on by controlling the first contactor 34 to open and the second contactor 35 to close to power the driver by the energy storage.
Specifically, in the case of power up, the capacitor 24 is precharged by the battery by controlling the contactor 34 to close and the contactor 35 to open to conduct the circuit in which it is located. Then, when the dc bus voltage displayed by the voltmeter 11 is equal to or greater than the first preset voltage (i.e., there is a stall risk), the energy consumption resistor consumes the feedback braking energy, so that the dc bus voltage (i.e., the feedback voltage) of the driver can be controlled to be lower than the protection voltage of the driver. At this time, since the actuator does not limit the intensity of the feedback brake, the speed of the overhead working truck can be controlled more and more slowly. Therefore, in the case where the dc bus voltage shown in the voltmeter 11 is less than or equal to the second preset voltage (i.e., the feedback voltage is close to the minimum operating voltage of the driver), the CPU 41 opens the contactor 34 and closes the contactor 35 to conduct the circuit thereof, so as to supply the power to the driver 2 through the capacitor 24, as shown in fig. 4. The capacitor 24 thus provides an auxiliary power source for the actuator 2 to complete the braking process (especially when the power system is de-energized). The function of the priming is thus to provide the drive 2 with backup energy to complete the deceleration process.
In contrast to the embodiment shown in fig. 3, the present embodiment shown in fig. 4 uses a pre-charge circuit comprising the contactor 34 and the resistor 60 to pre-charge the capacitor 24, and uses the contactor 35 to conduct another circuit in which the capacitor 24 is located to supply power to the driver by using the capacitor 24. Since the precharge circuit is separated from the power supply circuit, the present embodiment can achieve a more reliable power supply purpose; also, since the present embodiment employs a simpler switching device (i.e., contactor), it can achieve the control purpose in a simpler manner.
In an embodiment, the control system further comprises: a digital-to-analog converter 70 for converting the analog signal of the dc bus voltage detected by the voltage detection device 10 into a digital signal and outputting the digital signal of the converted dc bus voltage to the control device 40, as shown in fig. 3.
The overspeed control mode based on the direct current bus voltage can realize the downhill control of the vehicle. The control mode has a stall protection function, does not need to detect the speed of the vehicle and participate in speed control, and ensures that the driver can exert the braking capability of the motor to the maximum extent by stabilizing the voltage of the direct current bus, thereby preventing overspeed of the vehicle. Since the vehicle does not overspeed, it is less likely to stall. Therefore, during the operation of the overhead working truck, whether the battery is full, the limitation of a battery power Map (Map) or the direct current bus voltage of the driver caused by battery faults and the like is higher (or downhill stall), overspeed control based on the direct current bus voltage is inhibited from the source, and therefore the generation of the downhill stall risk is effectively prevented.
In summary, the present invention creatively firstly turns on the circuit of the energy storage device to precharge the energy storage device when power is on, then turns on the circuit of the energy consumer to capture feedback current by the energy consumer when the voltage of the direct current bus is equal to or greater than a first preset voltage, and then turns on the circuit of the energy storage device to supply power to the driver by the energy storage device when the voltage of the direct current bus is less than or equal to a second preset voltage. Therefore, the invention can intervene in the control strategy when the voltage of the direct current bus exceeds a first preset voltage (for example, a certain voltage smaller than the protection voltage of the driver) (i.e. before the occurrence of downhill overspeed), and the direct current bus voltage of the driver is reduced by capturing the feedback current, so that the braking torque is prevented from becoming smaller, the occurrence of the risk of downhill stall is effectively restrained, and the driver can be powered by the pre-charged electric energy when the voltage of the direct current bus is lower than a second preset voltage (for example, a certain voltage larger than the minimum working voltage of the driver), so that smooth parking is realized.
An embodiment of the present invention also provides an overhead working truck, which may include: the control system (namely the safety protection device) for the downhill working condition is described.
The aerial work vehicle may further include: a parking brake 120; and a driver 2 for controlling the parking brake 120 to perform braking in case that the rotational speed of the motor is less than a preset rotational speed.
In an embodiment, the aerial vehicle may further comprise: battery 80, vehicle Control Unit (VCU) 90, motor 100, speed reducer 130, wheels 140, DC/DC converter 150, and the like, as shown in fig. 2. Wherein, the battery 80 is configured with a Battery Management System (BMS), and a Vehicle Control Unit (VCU) 90 performs information interaction with the BMS through a CAN bus. The VCU 90 may adjust the target rotation speed of the motor 100 according to the battery state and the fault information transmitted from the BMS.
Specifically, the control system for downhill operation captures the feedback current generated by the regenerative braking, and the motor 100 can achieve deceleration control of the wheels 140 through the speed reducer 130, so that the vehicle speed is lower and lower, since the driver 2 does not limit the intensity of the feedback braking. And, in case that the rotational speed of the motor 100 is less than the preset rotational speed, smooth parking is achieved by controlling the parking brake to perform braking. Therefore, when the driving system fails, the mode of firstly decelerating and then contracting brake can be adopted, so that the damage to the parking brake is reduced as much as possible, and the service life of the parking brake is prolonged.
The embodiment can absorb the energy generated by the feedback braking through the resistor and timely control the speed reduction. When the feedback energy is insufficient, the electricity is timely supplemented through the pre-charged electricity of the energy storage capacitor, so that the normal operation of the driver is maintained until the driver is completely stopped. Therefore, the parking brake can be prevented from being damaged by dynamic impact energy, the probability of high-speed band-type brake can be greatly reduced, the service life of the parking brake is prolonged, the risk of parking on a slope is reduced, and accordingly safer and more reliable downhill can be realized.
Specific details and benefits of the aerial vehicle provided by the embodiments of the present invention can be found in the above description of the feedback current control device, and are not repeated here.
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims (10)

1. A control system for downhill conditions, the control system comprising:
the voltage detection device is used for detecting the direct current bus voltage of the driver;
the energy consumption device is used for capturing feedback current conveyed by the driver;
the first switching device is used for conducting a first circuit where the energy consumer is located;
an energy storage;
a second switching device for switching on a second circuit in which the energy storage device is located; and
control means for performing the following operations:
at power up, turning on the second circuit by controlling the second switching device to precharge the energy storage by the battery;
under the condition that the voltage of the direct current bus is equal to or greater than a first preset voltage, the first circuit is conducted by controlling the first switching device so as to capture the feedback current by the energy consumer; and
when the voltage of the direct current bus is less than or equal to a second preset voltage, the second circuit is conducted by controlling the second switching device to supply power to the driver by the energy accumulator,
wherein the first preset voltage is greater than the second preset voltage.
2. The control system of claim 1, wherein the first preset voltage is less than a protection voltage of the driver.
3. The control system of claim 1, wherein the second preset voltage is greater than a minimum operating voltage of the driver.
4. The control system of claim 1, wherein the first switching device is a first high frequency switch.
5. The control system of claim 4, wherein the control means for turning on the first circuit by controlling the first switching means comprises: switching on the first circuit by controlling the duty cycle of the first high frequency switch to control the speed at which the feedback current is captured by the consumer, and
in the case where the second switching means is a second high frequency switch, the control means for turning on the second circuit by controlling the second switching means to precharge the energy storage by the battery includes: the second circuit is turned on by controlling the duty cycle of the second high frequency switch to control the rate at which the accumulator is precharged by the battery.
6. The control system of claim 1, wherein, in the case where the second switching device includes a first contactor, a resistor, and a second contactor, the second circuit includes: the first sub-circuit is formed by connecting the first contactor and the resistor in series; and a second sub-circuit in which the second contactor is located, wherein both the first contactor and the resistor are connected in parallel with the second contactor,
accordingly, the control means for pre-charging the energy storage by the battery by controlling the second switching means to turn on the second circuit comprises: switching on the first sub-circuit by controlling the first contactor to close and the second contactor to open to precharge the energy storage by the battery, and
the control means for switching on the second circuit by controlling the second switching means to power the driver by the energy storage means comprises: the second sub-circuit is turned on by controlling the first contactor to open and the second contactor to close to power the driver by the energy storage.
7. The control system of claim 1, wherein the energy storage is a capacitor or a battery.
8. The control system of claim 1, wherein the energy consumer is a resistor.
9. An aerial work vehicle, the aerial work vehicle comprising: a control system for downhill conditions according to any of claims 1-8.
10. The aerial vehicle of claim 9, wherein the aerial vehicle further comprises:
a parking brake; and
and the driver is used for controlling the parking brake to brake under the condition that the rotating speed of the motor is smaller than the preset rotating speed.
CN202211090792.7A 2022-09-07 2022-09-07 Control system for downhill working condition and overhead working truck Pending CN116461330A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202211090792.7A CN116461330A (en) 2022-09-07 2022-09-07 Control system for downhill working condition and overhead working truck
PCT/CN2023/093829 WO2024051201A1 (en) 2022-09-07 2023-05-12 Control system for downhill working condition, and elevated work vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211090792.7A CN116461330A (en) 2022-09-07 2022-09-07 Control system for downhill working condition and overhead working truck

Publications (1)

Publication Number Publication Date
CN116461330A true CN116461330A (en) 2023-07-21

Family

ID=87182975

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211090792.7A Pending CN116461330A (en) 2022-09-07 2022-09-07 Control system for downhill working condition and overhead working truck

Country Status (1)

Country Link
CN (1) CN116461330A (en)

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