Power supply system based on capacitor charging and power storage and charging and discharging control method

Abstract

The invention relates to the technical field of instant release of a high-power power source, in particular to a power supply system based on capacitor charging and storage, a power system of an operation vehicle and a charging and discharging control method of a capacitor, and the power supply system based on capacitor charging and storage comprises the capacitor which is suitable for supplying power to an electric device; the engine works at the optimal fuel consumption working point at constant power; and the engine is connected with the generator and the capacitor and is suitable for converting mechanical energy of the engine into electric energy and charging the capacitor to adapt to behaviors and parameters of the capacitor. On the basis that an operation vehicle is usually intermittent operation equipment with huge power output difference, the engine, the generator and the capacitor form a power supply system, and the engine is artificially set to work at an optimal fuel consumption working point, so that the fuel consumption can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of instantaneous release of high-power electric energy and power sources, and in particular to a power supply system based on capacitor charging and storage, a power system of an operating vehicle, an operating vehicle, and a capacitor charging and discharging control method. Background Art

[0002] An excavator is a type of engineering machinery used to excavate earth, stone, ore and other materials. It is widely used in engineering construction, mining, municipal engineering and other fields.

[0003] Existing excavators use engines to power their buckets to achieve their digging needs. During operation, the bucket not only digs but also needs to be lifted, rotated, and moved after digging. The power required for each of these operations varies significantly, typically by more than 10 times. Existing technologies adjust the engine's power to meet these requirements, resulting in high fuel consumption. Summary of the Invention

[0004] The present invention provides a power supply system based on capacitor charging and storage, a power system for a work vehicle, a work vehicle, and a method for controlling the charging and discharging of a capacitor, to address one of the deficiencies in the prior art. Since work vehicles are typically intermittent work equipment with large variations in power output, the power supply system consisting of an engine, a generator, and a capacitor can effectively reduce fuel consumption by artificially setting the engine to operate at an optimal fuel consumption operating point.

[0005] The present invention provides a power supply system based on capacitor charging and storage, comprising: A capacitor, wherein the capacitor is suitable for supplying power to an electrical device; An engine, wherein the engine operates at a constant power and at an optimal fuel consumption operating point; The generator is connected to the engine and the capacitor, and is suitable for converting the mechanical energy of the engine into electrical energy to charge the capacitor in a manner adapted to the behavior and parameters of the capacitor.

[0006] A power supply system based on capacitor charging and storage according to the present invention further includes: A charging controller, wherein the generator is connected to the capacitor via the charging controller, and the charging controller is adapted to control the generator to charge the capacitor at a constant power.

[0007] The present invention provides a power system for a working vehicle, further comprising: The power supply system based on capacitor charging and storage as described above; A driving device is connected to the capacitor and is suitable for driving the action device of the working vehicle through power supply from the capacitor.

[0008] According to a power system of a working vehicle provided by the present invention, the driving device includes: an execution device, the execution device being adapted to be connected to an action device of the work vehicle; The electric motor is connected to the capacitor, and the electric motor is connected to the execution device, and is suitable for driving the action device of the working vehicle to act by powering the capacitor.

[0009] A power system for a work vehicle according to the present invention further includes: An integrated controller is provided, wherein the capacitor is connected to the controller of the motor through the integrated controller, and the parameters of the capacitor are adjusted to be suitable for powering the motor, and the corresponding signals of different load conditions are obtained and sent to the controller of the motor.

[0010] According to a power system of a working vehicle provided by the present invention, the engine is a diesel engine, a gasoline engine, a methanol engine, a natural gas engine, a liquefied petroleum gas engine, a hydrogen engine, a gas turbine, a steam engine, a steam turbine or a Stirling engine.

[0011] The present invention provides a working vehicle, comprising the power supply system based on capacitor charging and storage as described above, or the power system of the working vehicle as described above.

[0012] The present invention provides a control method for a power system of a work vehicle, which is applied to the power system of the work vehicle described above, comprising: Obtaining a first instruction to control the capacitor to discharge for a first duration, wherein the first instruction is a signal for an action device of the work vehicle to perform a main action, and the first duration is the duration required for the action device of the work vehicle to perform a main action; Obtaining a second instruction to control the generator to charge the capacitor for a second duration to reach a target charge, wherein the second instruction is a signal for the motion device of the work vehicle to perform an auxiliary action; the second duration is the duration required for the motion device of the work vehicle to perform an auxiliary action, and the target charge is the discharge amount of the capacitor when the motion device of the work vehicle performs at least one main action; The discharge power of the capacitor under the first instruction is greater than the discharge power of the capacitor under the second instruction.

[0013] The present invention provides a capacitor charging control method, characterized in that it is applied to the power supply system based on capacitor charging and storage as described above, comprising: Acquire signal parameters of the generator sampled multiple times, wherein the signal parameters of each sample include a load current and a load voltage; and obtain the instantaneous load power of the generator sampled each time based on the signal parameters of each sample; It is determined that the difference between the instantaneous load power and the target power exceeds the set load power variation range, and the instantaneous current and the instantaneous voltage are adjusted respectively until the difference between the instantaneous load power obtained by the instantaneous current and the instantaneous voltage and the target power meets the set load power variation range.

[0014] The present invention provides a capacitor discharge control method, characterized in that it is applied to the power system of the working vehicle as described above, comprising: Based on the relationship between circuit type and input and output current and voltage, the results of adjusting the large gradient voltage change up and down under the voltage change input characteristic of the capacitor are obtained; Among them, the relationship between the input and output current and voltage is that the ratio of the output voltage to the input voltage is the voltage gain, the ratio of the input current to the output voltage is the voltage gain, the voltage gain of the buck circuit is the switch tube conduction duty cycle, the voltage gain of the boost circuit is the reciprocal of the difference between 1 and the voltage gain, and the voltage gain of the buck-boost circuit is the ratio of the voltage gain to the difference between 1 and the voltage gain.

[0015] The power supply system based on capacitor charging and storage in an embodiment of the present invention is mainly composed of a capacitor, an engine and a generator. During the operation of the electrical device, the power supply system based on capacitor charging and storage can be used as the power source of the electrical device to provide power support for the operation of the electrical device.

[0016] In the power supply system based on capacitor charging and storage, the output shaft of the engine is connected to the input shaft of the generator. The engine can drive the generator to rotate, and then the mechanical energy generated by the engine is converted into electrical energy through the generator. The generator is connected to the capacitor. The electrical energy generated by the generator charges the capacitor to adapt to the capacitor's behavior and parameters. The capacitor can store electrical energy. During the operation of the electrical device, the capacitor can supply power to the electrical device by storing electricity.

[0017] The present invention generates electricity by driving an engine to generate a generator, which is then stored in a capacitor. This energy can be used as a power source for operating equipment, electromagnetic rail weapons, and other devices with widely varying power outputs. When applied to an operating vehicle, the capacitor discharges to provide an electric drive power source for the vehicle's actuating devices, thereby generating power. The power source, comprised of the engine, generator, and capacitor, works in conjunction with the electric motor as the power source for the entire vehicle. Compared to traditional engine-driven hydraulic pumps that power the actuating devices, the present invention eliminates the use of traditional large-displacement engines and replaces them with small-displacement engines. This allows the generator to convert electrical energy and charge the capacitor under idle conditions, thus replacing a large-displacement engine with a small-displacement engine to achieve reduced engine base fuel consumption and overall vehicle system fuel consumption.

[0018] The electrical energy stored in the capacitor can meet the driving requirements of the operating device of the working vehicle. When the operating device requires a large amount of power, the capacitor can discharge quickly to provide the operating device with sufficient energy to meet the working needs. When the operating device requires a small amount of power, the capacitor can provide the operating device with a smaller amount of energy to meet the working needs. The engine can always operate at a constant power at the optimal consumption working point. There is no need to adjust the power according to the energy requirements of the power device, which can avoid the problem of additional fuel consumption caused by power adjustment. Therefore, on the basis that the working vehicle is usually an intermittent working equipment with huge differences in power output, the power supply system composed of the engine, generator and capacitor, and the engine is artificially set to work at the optimal fuel consumption working point, can effectively reduce fuel consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 1 is a schematic structural diagram of a power system of a work vehicle provided by an embodiment of the present invention; Figure 2 4 is a flow chart of a capacitor charging control method provided by an embodiment of the present invention.

[0021] Reference numerals: 100, engine; 200, generator; 300, capacitor; 400, motor; 500, actuator; 600, integrated controller; 700, charging controller; 810, bucket; 820: turntable; 910, host; 920, DC / DC converter; 930, low-voltage circuit. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0025] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0026] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0027] like Figure 1 As shown, the power supply system based on capacitor charging and storage provided by an embodiment of the present invention includes a capacitor 300, an engine 100 and a generator 200, and the capacitor 300 is suitable for supplying power to electrical devices; the engine 100 operates at a constant power at an optimal fuel consumption operating point; the engine 100 is connected to the generator 200 and the capacitor 300, and is suitable for converting the mechanical energy of the engine 100 into electrical energy, and charging the capacitor 300 to adapt to the behavior and parameters of the capacitor 300.

[0028] The power supply system based on capacitor charging and storage of an embodiment of the present invention is mainly composed of a capacitor 300, an engine 100 and a generator 200. During the operation of the electrical device, the power supply system based on capacitor charging and storage can be used as the power source of the electrical device to provide power support for the operation of the electrical device.

[0029] In the power supply system based on capacitor charging and storage, the output shaft of the engine 100 is connected to the input shaft of the generator 200. The engine 100 can drive the generator 200 to rotate, and then the mechanical energy generated by the engine 100 is converted into electrical energy through the generator 200. The generator 200 is connected to the capacitor 300. The electrical energy generated by the generator 200 is used to charge the capacitor 300 to adapt to the behavior and parameters of the capacitor 300. The capacitor 300 can store the electrical energy. During the operation of the electrical device, the capacitor 300 can supply power to the electrical device by storing electricity.

[0030] The present invention generates electricity by driving a generator 200 through an engine 100, and storing the electrical energy of the generator 200 through a capacitor 300. This energy can be used as a power source for operating equipment, electromagnetic rail weapons, and other devices with significantly different power outputs. When applied to an operating vehicle, the discharge of the capacitor 300 provides an electric drive power source for the operating device of the operating vehicle, thereby generating power. The power source composed of the engine 100, the generator 200, and the capacitor 300, in conjunction with the electric motor, serves as the power source for the entire vehicle. Compared to the traditional engine 100 driving the hydraulic pump 500 to power the operating device, the present invention eliminates the use of the traditional large-displacement engine 100 and replaces it with a small-displacement engine 100. This can meet the requirements of driving the generator 200 for electrical energy conversion and charging the capacitor 300 under the premise of an idle state. By replacing the large-displacement engine 100 with the small-displacement engine 100, the base fuel consumption of the engine 100 and the fuel consumption of the entire vehicle system are reduced.

[0031] The electrical energy stored in the capacitor 300 can meet the driving requirements of the motion device of the working vehicle. When the motion device requires a large amount of power, the capacitor 300 can discharge quickly to provide sufficient energy for the motion device to meet the working needs. When the motion device requires a small amount of power, the capacitor 300 can provide a smaller amount of energy for the motion device to meet the working needs. The engine 100 can always operate at a constant power at the optimal consumption working point. There is no need to adjust the power according to the energy requirements of the power device, which can avoid the problem of additional fuel consumption caused by power adjustment. Therefore, on the basis that the working vehicle is usually an intermittent working equipment with huge differences in power output, the power supply system composed of the engine 100, the generator 200 and the capacitor 300, the engine 100 is artificially set to work at the optimal fuel consumption working point, which can effectively reduce fuel consumption.

[0032] According to an embodiment provided by the present invention, the power supply system based on capacitor charging and storage also includes a charging controller 700. The generator 200 is connected to the capacitor 300 through the charging controller 700. The charging controller 700 is suitable for controlling the generator 200 to charge the capacitor 300 at constant power.

[0033] In this embodiment, the power supply system based on capacitor charging and storage mainly consists of a capacitor 300, an engine 100, a generator 200, and a charge controller 700. The output end of the generator 200 is connected to the input end of the capacitor 300 through the charge controller 700. After the work vehicle is started, the engine 100 maintains constant power operation at the optimal fuel consumption operating point. The generator 200 continuously converts the mechanical energy of the engine 100 into electrical energy, and continuously charges the capacitor 300 through the charge controller 700. The charge controller 700 can adjust the output current and voltage of the generator 200 in real time, thereby achieving the effect of constant power charging of the capacitor 300 by the generator 200. When the capacitor 300 is fully charged, the engine 100 and the generator 200 can automatically shut down, or the engine 100 can idle.

[0034] In this embodiment, the charging controller 700 may be a DC-DC converter, an inverter, or the like.

[0035] According to an embodiment of the present invention, the capacitor 300 is a dry capacitor or a pure capacitor, and the charge and discharge rate is greater than 1000.

[0036] In this embodiment, compared with the electrolytic capacitor 300, the dry capacitor 300 has the advantages of no liquid electrolyte, resistance to low and high temperatures (working temperature is about -55°C to 90°C), and unlimited theoretical life, which fully meets the use requirements of working vehicles in high temperature and vibration environments.

[0037] In this embodiment, the energy storage capacity of capacitor 300 is converted from farads (F) to equivalent energy (Wh), which can support the energy requirements of the bucket 810's digging action and the actions of other auxiliary mechanisms, covering the energy requirements of small to large excavators.

[0038] An embodiment of the present invention also provides a power system for a working vehicle, including a power supply system based on capacitor charging and storage and a drive device as in the above embodiment, wherein the drive device is connected to the capacitor 300 and is suitable for driving the action device of the working vehicle through power supply from the capacitor 300.

[0039] In this embodiment, the power system of the work vehicle is primarily composed of a power supply system based on capacitor charging and storage, and a drive device. The drive device is connected to a capacitor 300, and the electrical energy stored in the capacitor 300 is used to power the drive device. The drive device is connected to the actuating device and provides driving force for the actuating device. The drive device has the ability to automatically adjust its output power. When the actuating device requires a large amount of power, the drive device outputs a large amount of power to drive the actuating device. When the actuating device requires a small amount of power, the drive device outputs a small amount of power to drive the actuating device. Compared to traditional power systems, in which the hydraulic pump 500 is driven directly by the engine 100, the drive device can precisely adjust power according to real-time load demand. This not only meets the working needs of the actuating device under different working conditions, but also achieves the power output required by the work vehicle through adjustment of the drive device, eliminating the need to adjust the power of the engine 100, thereby reducing fuel consumption.

[0040] In this embodiment, the work vehicle can be selected from various types of engineering vehicles, such as excavators, bulldozers, and loaders. In actual operations, there are intermittent working equipment with significant differences in power output. The motion device and the power system are both components of the work vehicle. For example, in an excavator, the motion device includes a main mechanism and auxiliary mechanisms. The main mechanism can be the bucket 810, and the auxiliary mechanism can be a turntable mechanism, cooling mechanism, and travel mechanism that cooperate with the bucket 810. The capacitor 300 can power the entire vehicle, including all electrical components, such as the motors 400, wiring, mainboard, and control components.

[0041] According to an embodiment provided by the present invention, the driving device includes an actuator 500 and an electric motor 400, and the actuator 500 is suitable for being connected to the action device of the working vehicle; the capacitor 300 is connected to the electric motor 400, and the electric motor 400 is connected to the actuator 500, and is suitable for driving the action device of the working vehicle to perform action by powering it through the capacitor 300.

[0042] In this embodiment, the drive device consists of an actuator 500 and a motor 400. The output end of the capacitor 300 is electrically connected to the input end of the motor 400. The output shaft of the motor 400 is connected to the input and output shafts of the actuator 500 via a coupling. The output end of the actuator 500 is connected to the actuating device. The drive device can be composed of multiple sets of actuators 500 and motors 400. Different combinations of actuators 500 and motors 400 can be used for different actuating devices.

[0043] When the work vehicle is an excavator and the motion device is an excavation mechanism, the actuator 500 is, for example, a hydraulic pump or actuator. The main mechanism is the bucket 810, and the auxiliary mechanisms include the turntable mechanism, cooling mechanism, and travel mechanism that cooperate with the bucket 810. The motor 400 drives the hydraulic pump combination to provide driving force for the main mechanism and other mechanisms. The hydraulic pump is connected to the main mechanism and the auxiliary mechanisms, directly converting hydraulic energy into mechanical motion for the main mechanism or the auxiliary mechanisms.

[0044] When the bucket 810 is digging, it requires huge power. The motor 400 needs to generate a large power output to drive the hydraulic pump and then drive the bucket 810 to dig. The capacitor 300 discharges on demand to provide the required energy for the motor 400 to meet the working needs of the bucket 810; after the digging action, when the auxiliary actions of the excavator such as walking, turntable rotation, height lifting, and bucket tipping require less energy, the motor 400 needs to generate a smaller power output, and the capacitor 300 also provides the motor 400 with the required energy to meet the working needs of the excavator such as walking, turntable rotation, height lifting, and bucket tipping.

[0045] According to an embodiment provided by the present invention, the power system of the working vehicle also includes an integrated controller 600, and the capacitor 300 is connected to the controller of the motor 400 through the integrated controller 600, and the parameters of the capacitor 300 are adjusted to be suitable for powering the motor 400, and the corresponding signals of different load conditions are obtained and sent to the controller of the motor 400.

[0046] In this embodiment, the power system of the working vehicle is mainly composed of a capacitor 300, an engine 100, a generator 200, a charging controller 700, a drive device and an integrated controller 600. The connection settings between the capacitor 300 and the motor 400 can be divided into two types. One is to connect the controller of the motor 400 itself only through the integrated controller 600, and the other is to connect the capacitor 300 to the motor 400 directly and also to the controller of the motor 400 itself through the integrated controller 600.

[0047] Integrated controller 600 receives and processes control signals from host computer 910, adjusting the parameters of capacitor 300 to suitably power motor 400. It also receives signals corresponding to different load conditions and transmits them to the controller of motor 400, thereby controlling motor 400 to adapt to the load. When the work vehicle is performing low-load operations, such as bucket 810 flipping or vehicle body movement, integrated controller 600 limits the current amplitude to achieve low-speed, high-precision operation of motor 400. When performing heavy-load operations, the current is increased to enable high-power and torque operation of motor 400, and the instantaneous high-current discharge capability of capacitor 300 is used to meet the peak power requirements of motor 400.

[0048] In this embodiment, the motor controller can adjust the speed and torque of motor 400 in real time to match the different working conditions of lifting or digging during excavation operations. The motor controller also integrates overvoltage, overcurrent, and overheating protection functions. When an abnormal signal is detected, it immediately disconnects capacitor 300 from motor 400 to prevent the fault from escalating.

[0049] According to an embodiment provided by the present invention, the engine 100 is a diesel engine, a gasoline engine, a methanol engine, a natural gas engine, a liquefied petroleum gas engine, a hydrogen engine, a gas turbine, a steam engine, a steam turbine or a Stirling engine.

[0050] In this embodiment, a wide range of work vehicle types are available. The engine 100 can be selected to suit different types of work vehicles and different operating conditions. The engine 100 can be a diesel engine, gasoline engine, methanol engine, natural gas engine, liquefied petroleum gas engine, hydrogen engine, gas turbine, steam engine, steam turbine, or Stirling engine. All types of engines 100 ensure that the engine 100 always operates at the optimal fuel consumption point regardless of load changes.

[0051] Among them, the diesel engine has a high torque density (>100N·m / kg), which is suitable for heavy-load excavation operations. The exhaust gas turbocharging technology is used to improve the power density and meet the power requirements of the engine's 100% optimal fuel point.

[0052] Among them, the lightweight design of the gasoline engine is suitable for small work vehicles (such as micro loaders). The air-fuel ratio is precisely controlled through the electronic throttle and oxygen sensor to optimize fuel economy.

[0053] Among them, methanol engines or natural gas engines use clean fuel, and carbon emissions are significantly reduced, 30% to 50% less than diesel engines. They are suitable for urban construction scenarios with high environmental protection requirements. The combustion chamber structure of engine 100 has been reinforced to adapt to fuel characteristics (such as the high octane number of methanol).

[0054] The work vehicle provided by the present invention is described below. The power systems of the work vehicle described below and the work vehicle described above can be referred to each other.

[0055] An embodiment of the present invention further provides a work vehicle, comprising the power supply system based on capacitor charging and storage as in the above embodiment, or the power system of the work vehicle in the above embodiment.

[0056] The working vehicle of the embodiment of the present invention can be selected from various types of engineering vehicles, such as excavators, loaders, etc. In actual operation, there are intermittent working equipment with huge differences in power output. The motion device and the power system are both components of the working vehicle. For example, in an excavator, the motion device includes a main mechanism and an auxiliary mechanism. The main mechanism can be a bucket 810, and the auxiliary mechanism can be a turntable mechanism, a cooling mechanism, a walking mechanism, etc. that cooperate with the bucket 810. The capacitor 300 can power the entire vehicle, including all electrical components, such as each motor 400, circuit, main board, control components, etc.

[0057] In addition to controlling the charging of capacitor 300 by generator 200, charge controller 700 can also draw its own power from capacitor 300. Host 910, serving as the control system for the work vehicle, can also draw its own power from capacitor 300. Host 910 integrates sensor data, such as the throttle, bucket 810 position, and hydraulic pressure, to coordinate the operating states of engine 100, charge controller 700, capacitor 300, and motor 400, implementing energy management (e.g., prioritizing capacitor 300 power and replenishing insufficient energy by engine 100), fault diagnosis, and safety protection (overload, overheating). A DC / DC converter 920 connects to capacitor 300, stabilizes its voltage, and supplies power to low-voltage line 930, such as lights, instruments, and sensors within the cab. It can also serve as a distributed electronic control unit, controlling specific subsystems, such as the cooling fan. A touchscreen integrated in the cab displays parameters such as the capacitor 300 charge, engine 100 speed, and component temperatures. The operator can send action commands (primary and auxiliary action signals) via the joystick.

[0058] The control method of the power system of the working vehicle provided by the present invention is described below. The control method of the power system of the working vehicle described below and the power system of the working vehicle described above can be referred to in correspondence with each other.

[0059] An embodiment of the present invention further provides a method for controlling a power system of a work vehicle, which is applied to the power system of the work vehicle in the above embodiment, comprising: Obtain a first instruction to control the capacitor 300 to discharge for a first duration, where the first instruction is a signal for the motion device of the work vehicle to perform a main action, and the first duration is the duration required for the motion device of the work vehicle to perform a main action; Obtain a second instruction and control the generator 200 to charge the capacitor 300 for a second period of time to reach a target power. The second instruction is a signal for the action device of the working vehicle to perform an auxiliary action. The second period of time is the time required for the action device of the working vehicle to perform an auxiliary action. The target power is the discharge amount of the capacitor 300 when the action device of the working vehicle performs at least one main action. The discharge power of the capacitor 300 under the first instruction is greater than the discharge power of the capacitor 300 under the second instruction.

[0060] In the control method for the power system of a work vehicle according to an embodiment of the present invention, the charging and discharging process of capacitor 300 is associated with the operation of the work vehicle. The main operation performed by the operation device of the work vehicle is limited to a high-load operation, and the auxiliary operation performed by the operation device of the work vehicle is limited to a low-load operation. Thus, the first instruction is an instruction for executing the main operation, and the second instruction is an instruction for executing the auxiliary operation. The discharge power of capacitor 300 under the first instruction is more than 10 times the discharge power of capacitor 300 under the second instruction, which is much greater than the discharge power of capacitor 300 under the second instruction. Under the first instruction, capacitor 300 is discharged as a whole, and under the second instruction, capacitor 300 is charged as a whole.

[0061] Taking an excavator as an example, the action device is the bucket 810, which actively performs the digging action, and the auxiliary actions are the rotation of the turntable and the flipping of the bucket 810 to drop materials. After receiving the instruction for the bucket 810 to perform a digging action, the capacitor 300 can be instantly discharged to the motor 400, and the motor 400 increases the power to meet the load requirements. The motor 400 can drive the hydraulic pump 500 to drive the bucket 810 to perform the digging action. After a first duration, the bucket 810 completes the digging action. Then, when the instruction for the turntable to rotate and the bucket 810 to flip and drop materials is received, the capacitor 300 discharges again to the motor 400, and the motor 400 reduces the power to meet the load requirements. The motor 400 can drive the hydraulic pump 500 to drive the turntable to rotate and the bucket 810 to flip and drop materials. After a second duration, the turntable rotation and the flipping and dropping of the bucket 810 are completed.

[0062] During the second period of continuous charging of the capacitor 300, the engine 100 always drives the generator 200 to generate electricity to charge the capacitor 300 at a constant power. After the second period of charging, the amount of electricity stored in the capacitor 300 must at least reach the amount of electricity required to complete one shoveling action. In this way, the capacitor 300 can be discharged when the action device performs a high-load action and charged when the action device performs a low-load action. After the discharge of the current high-load action is completed, the capacitor 300 is charged for the duration of the low-load action, so that the amount of electricity stored in the capacitor 300 meets the electricity requirement of the next high-load action. In this way, on the basis of meeting the intermittent working equipment with huge differences in power output, it can also ensure that the engine 100 only works at the optimal fuel consumption working point to charge the capacitor 300, thereby effectively reducing fuel consumption.

[0063] The following describes a capacitor charging control method provided by the present invention. The capacitor charging control method described below and the power system of the working vehicle described above can be referenced to each other.

[0064] like Figure 2 As shown, an embodiment of the present invention further provides a capacitor charging control method, which is applied to a power supply system based on capacitor charging and storage as in the above embodiment, comprising: Obtain signal parameters of the generator sampled more than 200 times, where the signal parameters of each sample include load current and load voltage; Based on the signal parameters of each sampling, the instantaneous load power of the generator 200 is obtained for each sampling; It is determined that the difference between the instantaneous load power and the target power exceeds the set load power variation range, and the instantaneous current and the instantaneous voltage are adjusted respectively until the difference between the instantaneous load power obtained by the instantaneous current and the instantaneous voltage and the target power meets the set load power variation range.

[0065] The capacitor charging control method of the embodiment of the present invention is applied to the charging controller 700 in the power system of the working vehicle to form a control scheme for constant power charging of the capacitor 300, that is, to maintain the output power P of the generator 200. out =V out ×I out Constant, dynamically adjust the instantaneous voltage V of the output of the generator 200 out and instantaneous current I out .

[0066] First, the signal parameters of the generator 200 output are detected, and the output signal of the generator within a period of time is sampled multiple times continuously. The signal parameters of each sampling are the instantaneous current and instantaneous voltage at the sampling moment, and the instantaneous load power is calculated based on the product of the instantaneous current and the instantaneous voltage. Then, the instantaneous load power is multiplied by the target power P.ref A comparison is made to determine whether the difference between the instantaneous load power and the target power exceeds the set load power variation range. If so, the instantaneous current and instantaneous voltage are adjusted respectively until the difference between the instantaneous load power and the target power obtained through the instantaneous current and instantaneous voltage of the engine in the subsequent sampling process meets the set load power variation range.

[0067] The target power is the power of the pre-set constant power charging of the capacitor. If the instantaneous load power and the target power do not meet the tolerance requirements, the instantaneous current and instantaneous voltage are controlled by dual variables to dynamically adjust the combination of voltage and current, such as step-up and step-down conversion, to maintain V×I=P ref ,power closed-loop control can be performed through MPPT (maximum power point tracking), ,adaptive algorithms, etc., to handle nonlinear coupling and limit the voltage and current range.

[0068] When the work vehicle performs low-load actions, such as the bucket 810 flipping or the vehicle body running, the motor controller 600 can limit the current amplitude to achieve low-speed and high-precision operation of the motor 400; when performing heavy-load actions, the current should be increased to enable the motor 400 to operate with high power and torque, and the peak power requirements of the motor 400 are met through the instantaneous large current discharge capability of the capacitor 300.

[0069] The following describes a method for controlling the discharge of a capacitor provided by the present invention. The capacitor design method described below and the power system of the working vehicle described above can be referred to in correspondence with each other.

[0070] An embodiment of the present invention further provides a capacitor discharge control method, which is applied to the power system of the above-mentioned working vehicle, comprising: Based on the relationship between circuit type and input and output current and voltage, the results of adjusting the large gradient voltage change up and down under the voltage change input characteristic of the capacitor are obtained; Among them, the relationship between input and output current and voltage is that the ratio of output voltage to input voltage is voltage gain, the ratio of input current to output voltage is voltage gain, the voltage gain of the buck circuit is the duty cycle of the switch tube, the voltage gain of the boost circuit is the inverse of the difference between 1 and the voltage gain, and the voltage gain of the buck-boost circuit is the ratio of the voltage gain to the difference between 1 and the voltage gain.

[0071] The present invention also provides a capacitor discharge control method for use in an integrated controller for a power system, and provides key design parameters and calculation methods for a high-power DC / DC converter suitable for high-power instantaneous buck-boost scenarios.

[0072] The basic relationships of capacitor discharge control are divided into: Buck (step-down), Boost (step-up), Buck-Boost (step-up and step-down), and the corresponding input-output voltage-current relationship and voltage gain.

[0073] Wherein, the duty cycle is defined as D = T on / T s , switch conduction time T on With the switching period T s The ratio of V o is the output voltage, V in is the input voltage, I o is the output current, I in is the input current.

[0074] The current imbalance formula is introduced in the multi-phase parallel current uniformity design of boost / lower tubes: Used to evaluate the current distribution uniformity of multi-phase systems; max(I phase ) is the maximum phase current, min(I phase ) is the minimum phase current, I avg is the average phase current.

[0075] The core components for voltage control are designed as follows: Calculation of inductor value: The formula for critical inductance value is given as follows for different topologies: f s is the switching frequency, ΔI L is the inductor current ripple (usually 20% to 40% of the load current).

[0076] Volt-second balance principle (steady-state condition), verifying the continuity of inductor current under steady-state conditions: V on ·T on =V off ·T off .

[0077] V on is the voltage across the inductor when the switch is on (e.g. Vin-Vout in a buck circuit); V off The voltage across the inductor when the switch is off (e.g. -Vout in the BUCK circuit); T on 、T off is the on / off time (T on +T off =Ts, switching period).

[0078] For example, in the Buck circuit (V in -V o )·D·T s =V o ·(1-D)·T s Capacitor ripple calculation: Output capacitor ripple current Output voltage ripple C o is the output capacitor value; The ESR (equivalent series resistance) of the capacitor is required to meet the ripple voltage less than 1% of the output voltage, that is, ΔV o <1%V o .

[0079] To clarify the maximum withstand voltage and current calculations for MOSFETs and diodes in different topologies, a 20% design margin must be reserved. The voltage / current stress formula for power devices is as follows: Conduct efficiency and loss analysis: The loss composition formula is as follows Efficiency conversion formula The target efficiency of high-power systems is >97%.

[0080] The voltage stress of power devices is as follows: The current stress is the peak current of the switch tube: A 20% margin must be reserved.

[0081] Thermal management design: Radiator thermal resistance requirements T j is the junction temperature (e.g. 150°C), T a is the ambient temperature, R θ,jc is the thermal resistance junction temperature coefficient, P total is the total power.

[0082] Water cooling flow calculation (400kW class) Q is the system heat load, C p is the specific heat capacity (water ≈ 4.2 kJ / kg·K), ΔT is the allowable temperature rise (e.g. 10°C), and ρ is the density of water.

[0083] Control loop parameter design: Output voltage feedback compensation The PID compensator compensates the circuit of the circuit model, and the PID compensator transfer function is K pis the proportional system (response speed), K i is the integral coefficient (eliminating static check), K d is the differential coefficient (to suppress oscillation), and S is the time.

[0084] Special working mode: CCM / DCM boundary conditions (critical load current) Among them, f s L is the low critical voltage; When the load current I o crit Enters DCM (discontinuous inductor current) mode.

[0085] An embodiment of the present invention further provides a capacitor design method, which is applied to the power system of the work vehicle in the above embodiment, comprising: The stored energy of the capacitor 300 is obtained based on the discharge time of the capacitor 300 and the load power; or the stored energy of the capacitor 300 is obtained based on the discharge time and discharge current of the capacitor 300, wherein the discharge time of the capacitor 300 is the time required for the excavation mechanism of the working vehicle to perform at least one excavation action; Based on the stored energy of the capacitor 300 , the rated charging voltage, discharge cut-off voltage, and capacitance value of the capacitor 300 are obtained.

[0086] The capacitor design method of the embodiment of the present invention is a capacitor design method for the power system of a work vehicle, which reversely deduces the relevant design parameters of the capacitor 300 based on the energy demand of the work vehicle when performing high-load operations. It is mainly divided into two cases. One is to obtain the stored energy of the capacitor 300 based on the discharge time and load power of the capacitor 300, and then obtain the rated charging voltage, discharge cut-off voltage and capacitance value of the capacitor 300 based on the stored energy of the capacitor 300; the other is to obtain the stored energy of the capacitor 300 based on the discharge time and discharge current of the capacitor 300, and then obtain the rated charging voltage, discharge cut-off voltage and capacitance value of the capacitor 300 based on the stored energy of the capacitor 300. Among them, the discharge time of the capacitor 300 is the time required for the excavation mechanism of the work vehicle to perform at least one excavation action. The excavation mechanism is the action device of the work vehicle, the excavation action is the main action, and the required time is the first duration.

[0087] Given the time t and load power P required for the excavator to perform a main action, the stored energy E of the capacitor 300 can be obtained based on the formula t = E / P. Based on the stored energy E, the rated charging voltage V of the capacitor 300 can be obtained. max , discharge cut-off voltage V min and the capacitance value C.

[0088] ​Knowing the discharge current I and time t required for the excavator to perform a main action, based on the formula t=C(V max -V min ) / I, we can get the stored energy C(V max -V min ), thereby obtaining the rated charging voltage V of the capacitor 300 max , discharge cut-off voltage V min and the capacitance value C.

[0089] According to an embodiment of the present invention, obtaining the rated charging voltage, discharge cut-off voltage, and capacitance value of the capacitor 300 based on the stored energy of the capacitor 300 includes: Based on the product of the discharge time and the load power of the capacitor 300, the product of the square difference between the rated charging voltage and the discharge cut-off voltage of the capacitor 300 and the capacitance value is obtained; Alternatively, based on the product of the discharge time and the discharge current of the capacitor 300 , the product of the difference between the rated charging voltage and the discharge cut-off voltage of the capacitor 300 and the capacitance value is obtained.

[0090] In this embodiment, based on the stored energy of the capacitor 300, the rated charging voltage, discharge cut-off voltage and capacitance value of the capacitor 300 are obtained. According to the basic capacity calculation formula, the energy E stored in the capacitor 300 is determined by the capacitance value C and the operating voltage V, that is, E = 1 / 2 × C (V 2 max -V 2 min ), so after the storage energy E of the capacitor 300 required by the working vehicle is known, a capacitor with a suitable capacitance value C and working voltage V can be found accordingly.

[0091] Since 1Wh = 3600J, the denominator is 2×3600=7200, which is converted into practical units (watt-hours Wh) as EWh=C(V 2 max -V 2 min ) / 7200.

[0092] The module parameters of the capacitor 300 can be selected as 7 105V 83F modules connected in series. The module parameters after series connection are 700V23.71F.

[0093] The stored energy of the capacitor module is: EWh=C(V 2 max-V 2 min) / 7200=23.71×(700 2 -0 2 ) / 7200=1.61KWh According to an embodiment of the present invention, the capacitor design method further includes: The capacitance value is corrected based on the system efficiency to obtain the actual capacitance value.

[0094] In this embodiment, there is energy loss in the actual power system, such as internal resistance and conversion efficiency η. In order to ensure that the energy actually released by the capacitor 300 during the discharge process is sufficient to cover the energy demand of the action device, the capacitance value needs to be corrected.

[0095] Corrected capacitance value C when considering system efficiency 实际 =C 理论 / η,C 理论 The capacitance value C is obtained through the above design, and η is usually taken as 0.8~0.95.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A power supply system based on capacitor charging and storage, characterized in that: include: A capacitor (300), wherein the capacitor (300) is suitable for supplying power to an electrical device; An engine (100), wherein the engine (100) operates at a constant power and at an optimal fuel consumption operating point; The generator (200) is connected to the engine (100) and the capacitor (300), and is suitable for converting the mechanical energy of the engine (100) into electrical energy, and charging the capacitor (300) in a manner adapted to the behavior and parameters of the capacitor (300).

2. The power supply system based on capacitor charging and storage according to claim 1, characterized in that: Also includes: A charging controller (700), wherein the generator (200) is connected to the capacitor (300) via the charging controller (700), and the charging controller (700) is adapted to control the generator (200) to charge the capacitor (300) at a constant power.

3. A power system for a working vehicle, characterized in that: include: The power supply system based on capacitor charging and storage as described in claim 1 or 2; A driving device is connected to the capacitor (300) and is suitable for driving the action device of the working vehicle via power supplied by the capacitor (300).

4. The power system of the working vehicle according to claim 3, characterized in that: The driving device comprises: an execution device (500), the execution device (500) being adapted to be connected to an action device of the work vehicle; The electric motor (400) is connected to the capacitor (300), and the electric motor (400) is connected to the execution device (500), and is suitable for driving the action device of the working vehicle to perform action by supplying power through the capacitor (300).

5. The power system of the working vehicle according to claim 4, characterized in that: Also includes: An integrated controller is provided, wherein the capacitor (300) is connected to the controller of the motor (400) through the integrated controller, and the parameters of the capacitor (300) are adjusted to be suitable for powering the motor (400), and corresponding signals of different load conditions are obtained and sent to the controller of the motor (400).

6. The power system of a working vehicle according to any one of claims 3 to 5, characterized in that: The engine (100) is a diesel engine, a gasoline engine, a methanol engine, a natural gas engine, a liquefied petroleum gas engine, a hydrogen engine, a gas turbine, a steam engine, a steam turbine or a Stirling engine.

7. A working vehicle, characterized in that: It includes the power supply system based on capacitor charging and storage as described in claim 1 or 2, or the power system of the working vehicle as described in any one of claims 3 to 6.

8. A method for controlling a power system of a working vehicle, characterized in that: A power system for a work vehicle according to any one of claims 3 to 6, comprising: Obtaining a first instruction to control the capacitor (300) to discharge for a first duration, wherein the first instruction is a signal for the operating vehicle's motion device to perform a main action, and the first duration is the duration required for the operating vehicle's motion device to perform a main action; obtaining a second instruction to control the generator (200) to charge the capacitor (300) for a second duration to reach a target power level, wherein the second instruction is a signal for the operating vehicle's motion device to perform an auxiliary action, and the second duration is the duration required for the operating vehicle's motion device to perform an auxiliary action, and the target power level is the discharge amount of the capacitor (300) when the operating vehicle's motion device performs at least one main action; The discharge power of the capacitor (300) under the first instruction is greater than the discharge power of the capacitor (300) under the second instruction.

9. A method for controlling charging of a capacitor, characterized in that: The power supply system based on capacitor charging and storage as claimed in claim 1 or 2 comprises: Acquiring multiple sampled signal parameters of the generator (200), wherein the signal parameters of each sample include a load current and a load voltage; and obtaining the instantaneous load power of the generator (200) of each sample based on the signal parameters of each sample; It is determined that the difference between the instantaneous load power and the target power exceeds the set load power variation range, and the instantaneous current and the instantaneous voltage are adjusted respectively until the difference between the instantaneous load power obtained by the instantaneous current and the instantaneous voltage and the target power meets the set load power variation range.

10. A method for controlling discharge of a capacitor, characterized in that: The power supply system based on capacitor charging and storage as claimed in claim 1 or 2 comprises: Based on the relationship between circuit type and input and output current and voltage, the results of adjusting the large gradient voltage change up and down under the voltage change input characteristic of the capacitor are obtained; Among them, the relationship between the input and output current and voltage is that the ratio of the output voltage to the input voltage is the voltage gain, the ratio of the input current to the output voltage is the voltage gain, the voltage gain of the buck circuit is the switch tube conduction duty cycle, the voltage gain of the boost circuit is the reciprocal of the difference between 1 and the voltage gain, and the voltage gain of the buck-boost circuit is the ratio of the voltage gain to the difference between 1 and the voltage gain.

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