Operating machinery drive systems, operating machinery drive methods and related equipment

Abstract

This invention provides a driving system, driving method, and related equipment for electric work machinery, belonging to the field of electric work machinery control technology. The system includes: an on-board step-down transformer, with its primary side connected to an external high-voltage power grid to step down high-voltage AC power to low-voltage AC power; and at least one synchronous motor mechanism, with its input terminal electrically connected to the secondary side of the on-board step-down transformer and its output terminal connected to the working mechanism of the electric work machinery to drive the working mechanism. This invention can improve the overall energy efficiency of electric work machinery.

Description

Technical Field

[0001] This invention relates to the field of work machinery control technology, specifically to a work machinery drive system, a work machinery drive method, and related equipment. Background Technology

[0002] In stationary work environments such as mines and ports, some electric work machines, such as electric-powered excavators, have been widely used due to their ability to operate continuously for extended periods with zero emissions. As the tonnage of these machines increases, their power requirements also rise significantly.

[0003] Currently, large-tonnage electric towed excavators primarily use low-voltage power supply for energy transmission. However, this method generates high current when transmitting high power, leading to significant voltage loss and energy consumption in the transmission lines. It also necessitates larger cable diameters and increased weight, resulting in high cable and drum costs and limiting the equipment's mobility and operating range. To circumvent the drawbacks of low-voltage, high-current operation, some solutions attempt to use high-voltage direct power supply combined with an asynchronous motor. However, asynchronous motors inherently suffer from low efficiency, low power density, and poor control performance, thus limiting the overall machine efficiency.

[0004] Furthermore, existing electric towed excavators lack the means to dynamically adjust the power supply voltage according to load conditions during operation. When the equipment is under light load or in standby mode, the power supply voltage remains constant, resulting in a high proportion of copper and iron losses and low system efficiency. When the equipment is under heavy load or rapid acceleration, excessively high voltage may cause stress impact on power devices, affecting system safety.

[0005] Therefore, how to construct a drive system that can achieve high-voltage and high-efficiency power supply and dynamically optimize the power supply voltage according to the operating conditions to improve the overall energy efficiency is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this application is to provide a machine operation drive system, machine operation drive method and related equipment to improve the overall energy efficiency of electric work machinery.

[0007] In a first aspect, embodiments of this application provide a work machinery drive system, the system comprising: The vehicle-mounted step-down transformer has its primary side connected to the external high-voltage power grid and is used to step down high-voltage AC power to low-voltage AC power. At least one synchronous motor mechanism, with its input end electrically connected to the secondary side of the vehicle-mounted step-down transformer and its output end connected to the working mechanism of the operating machinery, is used to drive the working mechanism.

[0008] Optionally, the system further includes: A DC bus is connected between the input terminal of the motor controller and the secondary side of the vehicle-mounted step-down transformer. An energy storage device is connected in parallel to the DC bus; The energy storage device includes: Energy storage unit; The converter unit is connected to the energy storage unit at one end and to the DC bus at the other end.

[0009] Optionally, the system further includes: The rectifier unit has its input end connected to the vehicle-mounted step-down transformer and its output end connected to the at least one synchronous motor mechanism. The synchronous motor mechanism includes a synchronous motor and a motor controller; The input terminal of the motor controller is electrically connected to the secondary side of the vehicle-mounted step-down transformer, and the output terminal of the motor controller is connected to the synchronous motor.

[0010] Secondly, embodiments of this application provide a method for driving work machinery, applied to the work machinery drive system as described in the first aspect, the method comprising: Obtain the total power requirement of the operating machinery; the total power requirement is determined based on the torque and speed of each synchronous motor mechanism in the operating machinery; When the total power demand exceeds a first preset threshold, the gear of the vehicle-mounted step-down transformer is adjusted according to the total power demand, the first reference power, and the second reference power to drive each synchronous motor mechanism in the operating machinery; the first reference power is less than the second reference power. When the total power demand is less than or equal to a first preset threshold, the vehicle-mounted step-down transformer is switched to the first gear to drive the various synchronous motor mechanisms in the working machinery.

[0011] Optionally, the tap position of the on-board step-down transformer is adjusted according to the total power demand, the first reference power, and the second reference power, including: When the total power demand is less than the first reference power, control the on-board step-down transformer to switch to the first gear. When the total power demand is greater than the second reference power, the vehicle-mounted step-down transformer is controlled to switch to the second gear, wherein the secondary side voltage corresponding to the first gear is higher than the secondary side voltage corresponding to the second gear.

[0012] Optionally, the method further includes: When the total power demand is greater than a first preset threshold and the state of charge of the energy storage unit is greater than a preset discharge threshold, the difference between the total power demand and the grid input power is determined. The minimum value between the difference and the maximum allowable discharge power of the energy storage unit is determined as the target discharge power of the energy storage unit. The control converter unit causes the energy storage unit to discharge to the DC bus at the target discharge power.

[0013] Optionally, the method further includes: When the total power demand is less than or equal to a first preset threshold and the state of charge of the energy storage unit is less than a preset charging threshold, the minimum value between the total power demand and the maximum allowable charging power of the energy storage unit is determined as the target charging power of the energy storage unit. The control converter unit causes the energy storage unit to charge from the DC bus at the target charging power. Optionally, the method further includes: When the DC bus voltage is greater than the first preset voltage, the energy storage unit is controlled to charge until the DC bus voltage drops below the first preset voltage. When the DC bus voltage is less than or equal to the second preset voltage, the output torque of the synchronous motor is stopped, and the second preset voltage is less than the first preset voltage.

[0014] Thirdly, embodiments of this application provide a working machinery drive device, the device comprising: Memory, configured to store computer program instructions; and The processor is configured to implement the working machinery driving method as described in the first aspect when executing the computer program instructions.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the working machinery driving method as described in any of the first aspects.

[0016] Fifthly, embodiments of this application provide a work machinery, the work machinery comprising: The work machinery drive system as described in the first aspect; and As described in the third aspect, the operating machinery drive device.

[0017] In the above technical solution, firstly, by setting up a high-voltage AC power interface and installing an on-board step-down transformer on the equipment, a power supply mode of high voltage on-board and on-board step-down is achieved. Compared with existing low-voltage, high-current transmission solutions, this system significantly reduces the transmission current at the same power level, significantly reducing line voltage loss and energy loss. Simultaneously, it greatly reduces the diameter and weight of the towing cable, effectively lowering cable and reel costs and improving the equipment's mobility and operating range. Compared with solutions using direct high-voltage power supply with asynchronous motors, this system uses synchronous motors instead of asynchronous motors, fully leveraging the advantages of synchronous motors' high efficiency, high power density, and good control performance, fundamentally solving the problem of limited overall efficiency caused by asynchronous motors. Secondly, by obtaining the total power demand, the on-board step-down transformer is controlled to switch between the second and first gear positions. When the equipment is under heavy load or rapid acceleration, switching to the second gear reduces the voltage stress on the power devices, ensuring system safety; when the equipment is under light load or standby, switching to the first gear further reduces copper and iron losses, improving system efficiency under light load conditions. By dynamically optimizing the power supply voltage, this method enables the system to maintain high operating efficiency across the entire operating range, further improving the overall energy efficiency.

[0018] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 The schematic diagram illustrates a structural schematic of a work machinery drive system according to an embodiment of this application; Figure 2 The schematic diagram illustrates a flow chart of a working machinery driving method according to an embodiment of this application; Figure 3 A schematic diagram of the hardware structure of a work machinery drive device according to an embodiment of this application is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0022] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0023] It should be noted that the machinery driving method provided in the subsequent embodiments of this application can be applied to machinery, including but not limited to electric excavators, electric shovels / electric excavators, tunnel boring machines and cranes. For the purpose of clearly illustrating the technical solution, the application of the machinery driving method to an electric excavator is used as an example to illustrate the embodiments.

[0024] The working machinery drive system of this application is described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, this application provides a working machinery drive system, the system comprising: an on-board step-down transformer, the primary side of which is connected to an external high-voltage power grid for stepping down high-voltage AC power to low-voltage AC power; and at least one synchronous motor mechanism, the input end of which is electrically connected to the secondary side of the on-board step-down transformer, and the output end of which is connected to the working mechanism of the working machinery for driving the working mechanism.

[0026] In this embodiment, the vehicle-mounted step-down transformer can be connected to an external high-voltage power grid via a high-voltage AC power interface. This interface, serving as the system's input, can be directly connected to high-voltage distribution networks in locations such as mines and ports to introduce 6kV or 10kV high-voltage AC power. The vehicle-mounted step-down transformer is fixedly installed on the body of the operating machinery (e.g., an electric towed excavator). Its primary side is connected to the high-voltage AC power interface via a high-voltage cable, while the secondary side outputs low-voltage AC power (e.g., 380V, 424V). Because the transformer is located within the equipment itself, high-voltage, low-current is transmitted over the long distance of the towed cable from the power grid interface to the equipment, significantly reducing cable diameter, cost, and weight, while also minimizing voltage drop and energy loss. In addition, the system includes a vehicle-mounted VCU, which acts as the system's brain, coordinating the entire system's operation and executing core control algorithms.

[0027] The synchronous motor mechanism includes a synchronous motor and a motor controller. The input terminal of the motor controller is electrically connected to the secondary side of the vehicle-mounted step-down transformer to convert low-voltage AC power into AC power with adjustable frequency and voltage to drive the synchronous motor. The output terminal of the motor controller is connected to the synchronous motor. In addition, it should be noted that the motor controller is connected to the vehicle-mounted step-down transformer through a rectifier unit, which is used to convert the AC power output from the vehicle-mounted step-down transformer into DC power and input it to the motor controller.

[0028] Synchronous motors, serving as the power actuators of the system, are connected to the hydraulic pumps or rotary reducers of the working mechanism. Their rotors utilize permanent magnets or electrically excited structures, offering higher efficiency, higher power density, and superior dynamic control performance compared to traditional three-phase asynchronous motors. The motor controller precisely controls the torque or speed of the synchronous motor based on vehicle control commands, thereby efficiently completing digging, slewing, and other operational actions.

[0029] The number of motor controllers corresponds one-to-one with the number of synchronous motors. The synchronous motors include a main pump motor and a rotary motor. The main pump motor uses a permanent magnet synchronous motor as the drive unit to drive the main pump. The rotary motor also uses a permanent magnet synchronous motor as the drive unit, connected to a rotary reducer, to drive the upper part of the vehicle to perform corresponding rotary movements.

[0030] By combining high-voltage power extraction, vehicle-mounted voltage reduction, high-efficiency motors and their control units, this system achieves decoupling of high-voltage transmission and low-voltage drive in its power supply architecture. It retains the economic efficiency of high-voltage power supply while fully leveraging the efficiency and performance advantages of synchronous motors. This effectively solves the problems of low efficiency, low power density, and poor control performance caused by the use of asynchronous motors when using high-voltage power supply in existing electric work machinery, significantly improving the overall operating efficiency and economy of the machine.

[0031] In one embodiment of this application, the system further includes: a DC bus connected between the input terminal of the motor controller and the secondary side of the vehicle-mounted step-down transformer; an energy storage device connected in parallel to the DC bus; the energy storage device includes: an energy storage unit; and a converter unit, one end of which is connected to the energy storage unit and the other end of which is connected to the DC bus.

[0032] In this embodiment, the DC bus is connected between the input terminal of the motor controller and the secondary side of the vehicle-mounted step-down transformer, and the energy storage device is connected in parallel to the DC bus. The DC bus serves as the DC power supply hub of the system, receiving the low-voltage AC power output from the secondary side of the vehicle-mounted step-down transformer after rectification, and simultaneously providing a stable DC input to each motor controller. This achieves the conversion of AC to DC power and energy transfer within the system, making the energy transmission between the vehicle-mounted step-down transformer, the energy storage device, and the motor controller more coordinated, and adapting to the energy demands of the synchronous motor drive and the charging and discharging energy interaction requirements of the energy storage device. The energy storage device is connected in parallel to the DC bus and can exchange power bidirectionally with the DC bus based on the real-time operating conditions of the machinery. When the machinery is in generator mode, it can recover excess energy generated by braking, etc., and release the stored energy when the machinery is in motor mode and the power demand is high. This realizes energy recovery and reuse, effectively smooths out the power peak during the working cycle of the machinery, reduces the average power drawn by the system from the external power grid, and also suppresses voltage fluctuations on the DC bus caused by load changes, improves the stability of the DC bus voltage, provides a better power supply environment for the motor controller and synchronous motor, and further ensures the operational reliability of the drive system.

[0033] In one embodiment of this application, the energy storage device includes an energy storage unit and a converter unit, one end of the converter unit is connected to the energy storage unit, and the other end is connected to the DC bus. The energy storage unit uses supercapacitors as its core energy storage device. Leveraging the high power density and rapid charging / discharging characteristics of supercapacitors, it can quickly respond to changes in the operating conditions of the machinery, enabling rapid storage and release of electrical energy. This is suitable for the rapid recovery of energy during excavator swing braking and the demand for high-power instantaneous output during heavy-duty operations. Compared to traditional energy storage devices, it better suits the dynamic operating characteristics of construction machinery. The converter unit is a bidirectional DC-DC converter, serving as a bridge for energy conversion and control between the energy storage unit and the DC bus. It can flexibly switch between two operating modes according to the system's control commands. When the energy storage unit needs to release energy to the DC bus, the converter unit operates in Boost mode, raising the lower voltage of the energy storage unit to the DC bus voltage, ensuring smooth energy output to the DC bus. When the DC bus needs to charge the energy storage unit, the converter unit operates in Buck mode, lowering the DC bus voltage to a level suitable for charging the energy storage unit, achieving stable energy input to the energy storage unit. Through precise control of the converter unit, voltage matching and controllable energy interaction between the energy storage unit and the DC bus are achieved, ensuring the precise and efficient execution of the charging and discharging actions of the energy storage device. This allows the energy recovery and release of the energy storage unit to be adapted to the total power demand of the operating machinery, giving full play to the role of the energy storage device in peak shaving and valley filling and stabilizing the bus voltage.

[0034] Figure 2 The illustration shows a schematic flowchart of a method for driving a work machine according to an embodiment of this application. Figure 2 As shown in the figure, this application provides a method for driving a work machinery, the method comprising: Step 201: Obtain the total power requirement of the operating machinery; the total power requirement is determined based on the torque and speed of each synchronous motor mechanism in the operating machinery; In this embodiment, the vehicle's VCU serves as the core control unit. It collects real-time operating parameters of all synchronous motors in the system through various motor controllers. Specifically, this includes key data such as current, voltage, output torque, and speed of the synchronous motors driving the working mechanism, including the main pump motor and slewing motor. Then, based on the corresponding power calculation formula and the collected operating parameters of each synchronous motor, the total power requirement of each individual motor is calculated. Finally, the total power requirements of all synchronous motors are summarized to obtain the total power requirement P of the entire working machinery. demandThe value of the total power demand reflects the working status of the equipment. When the value is greater than the first preset threshold of 0, it means that the equipment is in electric mode and needs to draw energy from the grid to drive the operating mechanism. When the value is less than 0, it means that the equipment is in generator mode and the braking and other actions of the operating mechanism will generate surplus energy, realizing energy feedback.

[0035] Step 202: When the total power demand exceeds a first preset threshold, adjust the gear of the vehicle-mounted step-down transformer according to the total power demand, the first reference power, and the second reference power to drive each synchronous motor mechanism in the working machinery; In one specific embodiment, adjusting the tap of the on-board step-down transformer according to the total power demand, the first reference power, and the second reference power includes: When the total power demand is less than the first reference power, control the on-board step-down transformer to switch to the first gear. When the total power demand is greater than the second reference power, the vehicle-mounted step-down transformer is controlled to switch to the second gear, wherein the secondary side voltage corresponding to the first gear is higher than the secondary side voltage corresponding to the second gear.

[0036] When the total power demand exceeds the second reference power, the core objective is to ensure system stability and component safety during high-power operation of the equipment. The second reference threshold P... high The setting can be based on the rated power of the operating machinery, preferably 70% of the equipment's rated power. The second setting is the pre-set basic output setting of the vehicle-mounted step-down transformer, corresponding to standard low-voltage AC power output on the secondary side, such as 380VAC. The total power demand P calculated by the vehicle's VCU is determined... demand Greater than the second benchmark threshold P high This indicates that the machinery is currently operating under heavy load conditions, such as high-power excavation or rapid heavy-load movement. At this time, the system's power demand is high. Maintaining a high voltage output would subject system components such as the transformer, rectifier unit, and motor controller to significant electrical stress. Therefore, the vehicle's VCU sends a gear switching command to the on-board step-down transformer, controlling it to switch to the second gear to supply power to the system with standard low-voltage output. This avoids continuous high-power operation of the equipment under high-voltage output conditions, reduces the workload of components from the power supply end, ensures the stable operation of the entire drive system, prevents component damage caused by high-power, high-voltage operation, and improves the safety of system operation.

[0037] When the total power demand is less than the first reference power, the core is to improve the system's power supply and transmission efficiency and reduce energy loss when the equipment operates at low power. The first reference threshold P... lowThe setting can be based on the rated power of the operating machinery, preferably 30% of the equipment's rated power. The first setting is the pre-set high-voltage output setting of the vehicle-mounted step-down transformer, corresponding to a lower low-voltage AC output voltage on the secondary side than the second setting, such as 424VAC. The total power demand P calculated by the vehicle's VCU is determined by... demand Less than or equal to the first baseline threshold P low This indicates that the machinery is currently operating under light load conditions, such as slow rotation, equipment idling, or light-load excavation. At this time, the system's power demand is low, and components do not need to bear the load of high power, thus meeting the conditions for high-voltage, low-power operation. Based on this, the vehicle's VCU sends a gear switching command to the on-board step-down transformer, controlling it to switch to the first gear, supplying power to the system with a higher low-voltage. According to electrical principles, with a fixed power demand, a higher voltage will correspondingly reduce the current in the power supply line, thereby significantly reducing copper losses and power transmission losses in the power supply line. Simultaneously, it reduces the self-losses of equipment such as the on-board step-down transformer and rectifier unit, improving the power supply and transmission efficiency of the entire drive system and achieving energy saving and consumption reduction.

[0038] Step 203: If the total power demand is less than or equal to the first preset threshold, switch the vehicle-mounted step-down transformer to the first gear to drive each synchronous motor mechanism in the working machinery.

[0039] In this embodiment, when P is determined demand When the voltage is ≤ 0, it indicates that the operating machinery is currently in generator mode. The VCU sends a gear switching command to the on-board step-down transformer, controlling it to switch to the first gear. The system needs to absorb the energy fed back by the synchronous motor. The higher DC bus voltage provides a wider charging voltage window for energy storage units such as supercapacitors, enabling the converter to store energy in the energy storage units more efficiently. This avoids the situation where overvoltage protection is triggered due to excessively high bus voltage, forcing energy to be consumed through the braking resistor, thereby maximizing the recovery of braking energy and achieving energy saving and consumption reduction.

[0040] In this embodiment, the total power demand is obtained, and the vehicle-mounted step-down transformer is controlled to switch between the second and first gear positions accordingly. When the equipment is under heavy load or rapid acceleration, switching to the second gear position can reduce the voltage stress on the power devices and ensure system safety; when the equipment is under light load or standby, switching to the first gear position can further reduce copper loss and iron loss, and improve system efficiency under light load conditions.

[0041] In one embodiment of this application, the method further includes: When the total power demand is greater than a first preset threshold and the state of charge of the energy storage unit is greater than a preset discharge threshold, the difference between the total power demand and the grid input power is determined. The minimum value between the difference and the maximum allowable discharge power of the energy storage unit is determined as the target discharge power of the energy storage unit. The control converter unit causes the energy storage unit to discharge to the DC bus at the target discharge power.

[0042] In this embodiment, the preset discharge threshold is the minimum state of charge (SOC) threshold of the energy storage unit (preferably 30%). This threshold is set to ensure that the energy storage unit retains a basic amount of charge, preventing damage to the energy storage device due to over-discharge. When the SOC of the energy storage unit is greater than the preset discharge threshold, the energy storage unit is determined to have discharge capability and can participate in the system power supply. The grid input power is the actual power input to the DC bus from the external high-voltage grid through the vehicle-mounted step-down transformer and rectifier unit. The vehicle VCU obtains this value by collecting the grid-side power supply parameters in real time. When the equipment is operating at high power, the grid input power alone cannot fully match the total power demand of the entire machine. At this time, the difference between the total power demand of the entire machine and the grid input power is used as the basis, combined with the maximum allowable discharge power of the energy storage unit for limit processing. The minimum value between the two is taken as the target discharge power of the energy storage unit. This ensures that the discharge power of the energy storage unit can make up for the power gap of the grid power supply, and avoids damage to the energy storage unit and converter unit due to over-power discharge, thus achieving accurate and safe setting of the discharge power.

[0043] The control converter unit enables the energy storage unit to discharge to the DC bus at the target discharge power. The converter unit is a bidirectional DC-DC converter. The vehicle's VCU sends corresponding control commands to the converter unit based on the calculated target discharge power, controlling the converter unit to switch to Boost mode. This boosts the low-voltage DC output from the energy storage unit to a voltage level matching the DC bus, allowing the energy storage unit to stably release energy to the DC bus according to the set target discharge power. The released energy merges with the grid input on the DC bus, jointly powering the motor controller and synchronous motor, supplementing the power demand during high-power operation of the equipment, and achieving joint power supply from the grid and the energy storage unit.

[0044] In addition, if the state of charge of the energy storage unit is less than or equal to the preset discharge threshold, it indicates that the energy storage unit does not meet the discharge requirements, and the power demand at the back end is entirely provided by the grid input.

[0045] In this embodiment, on the one hand, the system's requirements for peak power on the grid side are reduced, thereby reducing the overall system cost; on the other hand, the instantaneous high power output of the energy storage unit improves the system's dynamic response capability, ensures the stability of power output when the equipment is under heavy load, and at the same time reduces the power impact on power supply equipment such as vehicle transformers and rectifier units, extending their service life.

[0046] In one embodiment of this application, the method further includes: When the total power demand is less than or equal to a first preset threshold and the state of charge of the energy storage unit is less than a preset charging threshold, the minimum value between the total power demand and the maximum allowable charging power of the energy storage unit is determined as the target charging power of the energy storage unit. The control converter unit enables the energy storage unit to be charged from the DC bus at the target charging power.

[0047] In this embodiment, the total power demand is less than or equal to a first preset threshold. If the working machinery is in a power generation state at this time, it indicates that the equipment generates surplus energy such as slewing braking and feeds it back to the DC bus. The preset charging threshold is the highest state of charge (SOC) threshold of the energy storage unit (preferably 80%). This threshold is set to reserve charging margin for the energy storage unit to avoid overcharging and damage to the devices. When the SOC of the energy storage unit is less than the preset charging threshold, it is determined that the energy storage unit has charging space and can recover surplus energy from the DC bus. The maximum allowable charging power of the energy storage unit is the upper limit of charging power determined by its hardware specifications. The vehicle VCU compares the total power demand fed back by the equipment with the maximum allowable charging power and takes the minimum of the two as the target charging power. This ensures that the energy storage unit recovers surplus energy at an appropriate power, avoiding the charging power exceeding the hardware capacity of the energy storage unit, and maximizes the utilization of the feedback energy generated by the equipment, thereby improving energy recovery efficiency.

[0048] The control converter unit enables the energy storage unit to charge from the DC bus at the target charging power. The converter unit is a bidirectional DC-DC converter. The vehicle's VCU sends corresponding control commands to the converter unit based on the calculated target charging power, controlling the converter unit to switch to Buck converter mode. This reduces the high-voltage DC power on the DC bus to a voltage level suitable for charging the energy storage unit, achieving stable charging of the energy storage unit from the DC bus. During this process, excess energy generated during operating conditions such as braking of the machinery is stored in the energy storage unit via the DC bus and the converter unit, replacing the traditional method of consuming excess energy through braking resistors, thus achieving energy recovery and reuse.

[0049] In addition, if the state of charge of the energy storage unit is greater than or equal to the preset charging threshold, it indicates that the energy storage unit does not meet the charging requirements, and charging will stop. All braking energy will be consumed by the braking resistor.

[0050] In this embodiment, line and equipment losses during energy recovery are further reduced, and the charging voltage range of energy storage units such as supercapacitors is broadened, making energy recovery more efficient. At the same time, the frequency of use of the braking resistor is reduced, lowering its heat loss and helping to extend the service life of the entire drive system.

[0051] In one embodiment of this application, the method further includes: When the DC bus voltage is greater than the first preset voltage, the energy storage unit is controlled to charge until the DC bus voltage drops below the first preset voltage. When the DC bus voltage is less than or equal to the second preset voltage, the output torque of the synchronous motor is stopped, and the second preset voltage is less than the first preset voltage.

[0052] In this embodiment, when the DC bus voltage exceeds a first preset voltage, the energy storage unit is controlled to charge until the DC bus voltage drops below the first preset voltage. The first preset voltage is the upper limit of the safe operating voltage of the DC bus (preferably 600VDC). This threshold is set according to the withstand voltage specifications and safe operating parameters of each component in the system. When the vehicle's VCU detects that the DC bus voltage Vdc exceeds this first preset voltage in real time, it determines that the system is in a high-voltage dangerous state. At this time, overvoltage on the DC bus can easily cause capacitors, semiconductor devices, and other electronic components to break down, leading to system failure. Based on this, the vehicle's VCU immediately triggers the overvoltage protection mechanism, forcibly controlling the energy storage unit to enter charging mode. The energy storage unit first absorbs excess energy from the DC bus to quickly reduce the bus voltage. If the energy storage unit's charging still cannot effectively reduce the bus voltage below the first preset voltage, a braking resistor will be activated simultaneously to consume excess energy on the bus. This dual protection ensures a rapid drop in the bus voltage until it falls below the safe range of the first preset voltage, at which point the overvoltage protection is released, and the system's normal power regulation logic is restored.

[0053] When the DC bus voltage is less than or equal to a second preset voltage, the output torque of the synchronous motor is limited. The second preset voltage is less than the first preset voltage. The second preset voltage is the lower limit of the safe operating voltage of the DC bus (preferably 540VDC). This threshold is set in conjunction with the minimum operating voltage requirements of the synchronous motor and motor controller. When the vehicle's VCU detects in real time that the DC bus voltage Vdc is less than or equal to this second preset voltage, it determines that the system is in a low-voltage dangerous state. In this case, insufficient bus voltage will lead to insufficient output power and speed fluctuations in the synchronous motor, and may even cause undervoltage alarms in the motor controller and system power failure. Based on this, the vehicle's VCU immediately triggers the undervoltage protection mechanism. By sending torque limiting commands to each motor controller, the maximum output torque of all synchronous motors is reduced by a preset ratio, reducing the power demand of the synchronous motors on the DC bus. This prevents further voltage drop on the bus due to continuous high current output, prevents system power failure due to undervoltage, and ensures the basic power supply of the drive system and the basic operational capability of the equipment. The torque limitation of the synchronous motor is gradually released and its normal power output is restored until the DC bus voltage recovers to a safe range above the second preset voltage.

[0054] In this embodiment, the transformer tap and energy storage unit operating status are adjusted according to power demand under normal system operating conditions. When the bus voltage is abnormal, the protection strategy is immediately triggered and executed first, realizing the coordination of operating condition control and safety protection. This allows the entire drive system to operate efficiently while having a complete ability to cope with abnormal operating conditions, greatly improving the reliability and service life of the system.

[0055] Figure 3 A schematic diagram of the hardware structure of the work machinery drive device provided in the embodiment of this application is shown.

[0056] The machine drive unit may include a processor 301 and a memory 302 storing program instructions.

[0057] When processor 301 executes the program, it implements the steps in any of the above method embodiments.

[0058] For example, the program can be divided into one or more modules / units, one or more of which are stored in memory 302 and executed by processor 301 to complete this application. The one or more modules / units can be a series of program instruction segments capable of performing a specific function, which describe the execution process of the program in the device.

[0059] Specifically, the processor 301 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0060] Memory 302 may include mass storage for data or instructions. For example, and not limitingly, memory 302 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 302 may include removable or non-removable (or fixed) media. Where appropriate, memory 302 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 302 is non-volatile solid-state memory.

[0061] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to one aspect of this disclosure.

[0062] The processor 301 implements any of the methods described above by reading and executing program instructions stored in the memory 302.

[0063] In one example, the working machinery drive unit may also include a communication interface 303 and a bus 310. The processor 301, memory 302, and communication interface 303 are connected via the bus 310 and communicate with each other.

[0064] The communication interface 303 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0065] Bus 310 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 310 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0066] Furthermore, in conjunction with the methods in the above embodiments, this application embodiment can provide a storage medium for implementation. This storage medium stores program instructions; when these program instructions are executed by a processor, they implement any of the methods in the above embodiments.

[0067] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run programs or instructions to implement the various processes of the above method embodiments and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0068] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0069] This application provides a computer program product, which is stored in a storage medium and executed by at least one processor to implement the various processes of the above method embodiments and achieve the same technical effects. To avoid repetition, it will not be described again here.

[0070] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0071] The functional modules shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on machine-readable media or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable media" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer grids such as the Internet, intranets, etc.

[0072] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0073] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to create a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0074] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A work machine drive system characterized by, The system includes: The vehicle-mounted step-down transformer has its primary side connected to the external high-voltage power grid and is used to step down high-voltage AC power to low-voltage AC power. At least one synchronous motor mechanism, with its input end electrically connected to the secondary side of the vehicle-mounted step-down transformer and its output end connected to the working mechanism of the operating machinery, is used to drive the working mechanism.

2. The system of claim 1, wherein, The system also includes: A DC bus is connected between the input terminal of the motor controller and the secondary side of the vehicle-mounted step-down transformer. An energy storage device is connected in parallel to the DC bus; The energy storage device includes: Energy storage unit; The converter unit is connected to the energy storage unit at one end and to the DC bus at the other end.

3. The system as described in claim 1, characterized in that, The system also includes: The rectifier unit has its input end connected to the vehicle-mounted step-down transformer and its output end connected to the at least one synchronous motor mechanism. The synchronous motor mechanism includes a synchronous motor and a motor controller; The input terminal of the motor controller is electrically connected to the secondary side of the vehicle-mounted step-down transformer, and the output terminal of the motor controller is connected to the synchronous motor.

4. A method for driving a work machinery, characterized in that, The method, applied to the work machinery drive system as described in any one of claims 1-3, comprises: Obtain the total power requirement of the operating machinery; the total power requirement is determined based on the torque and speed of each synchronous motor mechanism in the operating machinery; When the total power demand exceeds a first preset threshold, the gear of the vehicle-mounted step-down transformer is adjusted according to the total power demand, the first reference power, and the second reference power to drive each synchronous motor mechanism in the operating machinery; the first reference power is less than the second reference power. When the total power demand is less than or equal to a first preset threshold, the vehicle-mounted step-down transformer is switched to the first gear to drive the various synchronous motor mechanisms in the working machinery.

5. The method as described in claim 4, characterized in that, Based on the total power demand, the first reference power, and the second reference power, adjust the tap of the on-board step-down transformer, including: When the total power demand is less than the first reference power, control the on-board step-down transformer to switch to the first gear. When the total power demand is greater than the second reference power, the vehicle-mounted step-down transformer is controlled to switch to the second gear, wherein the secondary side voltage corresponding to the first gear is higher than the secondary side voltage corresponding to the second gear.

6. The method as described in claim 4, characterized in that, The method further includes: When the total power demand is greater than a first preset threshold and the state of charge of the energy storage unit is greater than a preset discharge threshold, the difference between the total power demand and the grid input power is determined. The minimum value between the difference and the maximum allowable discharge power of the energy storage unit is determined as the target discharge power of the energy storage unit. The control converter unit causes the energy storage unit to discharge to the DC bus at the target discharge power.

7. The method as described in claim 4, characterized in that, The method further includes: When the total power demand is less than or equal to a first preset threshold and the state of charge of the energy storage unit is less than a preset charging threshold, the minimum value between the total power demand and the maximum allowable charging power of the energy storage unit is determined as the target charging power of the energy storage unit. The control converter unit enables the energy storage unit to be charged from the DC bus at the target charging power.

8. The method as described in claim 4, characterized in that, The method further includes: When the DC bus voltage is greater than the first preset voltage, the energy storage unit is controlled to charge until the DC bus voltage drops below the first preset voltage. When the DC bus voltage is less than or equal to the second preset voltage, the output torque of the synchronous motor mechanism is stopped, and the second preset voltage is less than the first preset voltage.

9. A drive device for a work machinery, characterized in that, The device includes: Memory, configured to store computer program instructions; and The processor is configured to implement the machine drive method as described in any one of claims 4-7 when executing the computer program instructions.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions that, when executed by a processor, implement the machine driving method as described in any one of claims 4-7.

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