Control method of hybrid power system, hybrid power system and hybrid excavator

Abstract

The invention discloses a control method of a hybrid power system, the hybrid power system and a hybrid excavator. The control method of the hybrid power system comprises the steps that the required power of a hydraulic system, the required power of an electrically-driven rotation system and the current electric quantity of an energy storage module are obtained; the total demand power of the system is calculated according to the demand power of the hydraulic system and the demand power of the electric drive rotation system; determining the working mode of the hybrid power system according to the size relation between the total demand power and a first preset value and the size relation between the current electric quantity of the energy storage module and an electric quantity limit value; when the hybrid power system is in the heavy load mode, the generator motor is controlled to provide power for the hydraulic system; and when the hybrid power system is in the light load mode, the generator motor is controlled to convert part of kinetic energy generated by the engine into electric energy to charge the energy storage module. The system reliability can be enhanced, energy consumption and emission are reduced, and efficient utilization of energy is achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of excavators, and in particular, to a control method for a hybrid power system, a hybrid power system, and a hybrid excavator. Background Art

[0002] With the increasingly strict environmental protection regulations and the increasing requirements for energy efficiency, hybrid power technology has gradually been applied in various construction machinery.

[0003] Traditional excavators use engines as the main power source, resulting in high fuel consumption and large environmental pollution. Although all-electric excavators can reduce emissions, they are limited by battery capacity, with limited endurance and operating intensity. Therefore, adopting hybrid power technology, that is, combining the advantages of engines and electric motors, is an important way to improve the performance and efficiency of excavators.

[0004] However, although existing hybrid excavators can achieve a certain optimization of power output through the coordinated operation of engines and electric motors, most of them adopt a power distribution method based on the system speed for single-parameter control. The existing control method will cause inaccurate demand power calculation and excessive load estimation deviation in some working conditions of hybrid excavators, resulting in poor energy-saving effects and low system reliability. Summary of the Invention

[0005] The present invention provides a control method for a hybrid power system, a hybrid power system, and a hybrid excavator to enhance system reliability, reduce energy consumption and emissions, and achieve efficient utilization of energy.

[0006] In a first aspect, an embodiment of the present invention provides a control method for a hybrid power system. The hybrid power system includes a hydraulic system and an electric drive slewing system. The hydraulic system is powered by an engine and a generator motor, and the electric drive slewing system and the generator motor are powered by an energy storage module. The control method includes:

[0007] Obtain the demand power of the hydraulic system, the demand power of the electric drive slewing system, and the current power of the energy storage module;

[0008] Calculate the total demand power of the system according to the demand power of the hydraulic system and the demand power of the electric drive slewing system;

[0009] Determine the working mode of the hybrid power system according to the magnitude relationship between the total demand power and a first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value; wherein, the working mode includes a heavy load mode and a light load mode;

[0010] When the hybrid power system is in the heavy load mode, control the power generation motor to provide power for the hydraulic system; when the hybrid power system is in the light load mode, control the power generation motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module.

[0011] In a second aspect, an embodiment of the present invention further provides a hybrid power system, which includes a hydraulic system, an electric drive slewing system, an energy storage module, a power generation motor, and a control module;

[0012] The control module is respectively communicatively connected to the hydraulic system, the electric drive slewing system, the power generation motor, and the energy storage module; the energy storage module is electrically connected to the electric drive slewing system and the power generation motor respectively;

[0013] The hydraulic system includes an engine and a power output module, and the power output module is powered by the engine and the power generation motor; the energy storage module supplies power to the electric drive slewing system and the power generation motor; the power generation motor is also used to charge the energy storage module;

[0014] The control module is used to obtain the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module, and calculate the total required power of the system according to the required power of the hydraulic system and the required power of the electric drive slewing system; the control module is also used to determine the working mode of the hybrid power system according to the magnitude relationship between the total required power and a first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value; when the hybrid power system is in the heavy load mode, control the power generation motor to provide power for the hydraulic system; when the hybrid power system is in the light load mode, control the power generation motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module.

[0015] In a third aspect, an embodiment of the present invention further provides a hybrid excavator, and the hybrid excavator includes the hybrid power system according to any embodiment of the present invention.

[0016] The present invention provides a control method for a hybrid power system, a hybrid power system, and a hybrid excavator. By obtaining the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module, the total required power of the system is calculated according to the required power of the hydraulic system and the required power of the electric drive slewing system. Then, according to the magnitude relationship between the total required power and the first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value, the working mode of the hybrid power system is distinguished to determine the working mode of the hybrid power system, so as to control the system in combination with the working mode of the system and flexibly adjust the power output. When the hybrid power system is in the heavy load mode, the generator motor is controlled to provide power for the hydraulic system to assist the hydraulic system in outputting force, improving the power and reliability of the hydraulic system. When the hybrid power system is in the light load mode, the generator motor is controlled to convert part of the kinetic energy generated by the engine into electric energy to charge the energy storage module, so as to recover the redundant power and improve the energy management. The present invention can flexibly adjust the output of the engine and the generator motor according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, and can reduce energy consumption and emissions, realizing the efficient utilization of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flowchart of a control method for a hybrid power system provided by an embodiment of the present invention;

[0018] Figure 2 It is a flowchart of another control method for a hybrid power system provided by an embodiment of the present invention;

[0019] Figure 3 It is a flowchart of yet another control method for a hybrid power system provided by an embodiment of the present invention;

[0020] Figure 4 It is a flowchart of a control method for an energy storage module in a hybrid power system provided by an embodiment of the present invention;

[0021] Figure 5 It is a schematic diagram of the state of charge division of an energy storage module provided by an embodiment of the present invention;

[0022] Figure 6 It is a flowchart of another control method for an energy storage module in a hybrid power system provided by an embodiment of the present invention;

[0023] Figure 7 It is a schematic diagram of the structure of a hybrid power system in an embodiment of the present invention;

[0024] Figure 8 It is a schematic diagram of the structure of another hybrid power system in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only the parts related to the present invention rather than all the structures are shown in the drawings.

[0026] An embodiment of the present invention provides a control method for a hybrid power system. This embodiment of the present invention is applicable to a hybrid power system, which enhances system reliability, reduces energy consumption and emissions, and realizes efficient utilization of energy through a control strategy. The control method of the hybrid power system can be executed by a control device of the hybrid power system. The control device can be implemented in the form of hardware and / or software, and can be configured in the hybrid power system. The hybrid power system can include a hydraulic system and an electric drive slewing system. The hydraulic system is powered by an engine and a motor-generator, and the electric drive slewing system and the motor-generator are powered by an energy storage module. Figure 1 The flowchart of a control method for a hybrid power system provided by an embodiment of the present invention is as Figure 1 shown. The control method of the hybrid power system includes:

[0027] S110. Obtain the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module.

[0028] Among them, the energy storage module can be a super capacitor. The hybrid power system can be applied to an excavator. The hydraulic system in the hybrid power system can provide power for components such as the bucket, boom, and crawler of the excavator, and the electric drive slewing system can provide power for the slewing component in the excavator. The electric drive slewing system is powered by the energy storage module. The motor-generator can not only provide power for the hydraulic system but also charge the energy storage module. Under different working loads, environmental conditions, and operation requirements, the working mode of the motor-generator is different. Therefore, the key to improving the efficiency and stability of the hybrid power system is to adjust the collaborative working mode of the engine and the motor-generator in real time according to the working load, environmental conditions, and operation requirements.

[0029] Specifically, the required power of the hydraulic system can be obtained by acquiring the operation control signal corresponding to the hydraulic system and combining it with the load of the excavator. The required power of the electric drive slewing system can be obtained through the corresponding slewing control signal. The operation control signal and the slewing control signal can be generated by the excavator driver operating the excavator. By obtaining the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module, the total required power of the system can be calculated according to the required power of the hydraulic system and the required power of the electric drive slewing system. The working mode of the system can be judged through the total required power.

[0030] S120. Calculate the total required power of the system based on the required power of the hydraulic system and the required power of the electric drive slewing system.

[0031] Specifically, the total required power of the system can be the sum of the required power of the hydraulic system and the required power of the electric drive slewing system. The total required power of the system can also be the sum of the required power of the hydraulic system, the required power of the electric drive slewing system, and the required power of other modules of the hybrid power system. By calculating the total required power of the system based on the required power of the hydraulic system and the required power of the electric drive slewing system, the operating mode of the system can be determined based on the total required power and the current power level of the energy storage module.

[0032] S130. Determine the operating mode of the hybrid power system based on the magnitude relationship between the total required power and the first preset value, and the magnitude relationship between the current power level of the energy storage module and the power limit value; where the operating mode includes a heavy load mode and a light load mode.

[0033] Among them, when determining the magnitude relationship between the current power level of the energy storage module and the power limit value, only when the current power level of the energy storage module meets the power limit value, the operating mode of the hybrid power system is determined as the heavy load mode and the light load mode, so as to protect the energy storage module. For example, the power limit value can include a charging limit value and a discharging limit value. When the current power level of the energy storage module is greater than the charging limit value, continuous charging will cause overcharging of the energy storage module. When the current power level of the energy storage module is less than the discharging limit value, continuous discharging will cause over-discharging of the energy storage module. Therefore, setting the power limit value can prevent over-discharging or overcharging of the energy storage module.

[0034] Specifically, based on the magnitude relationship between the total required power and the first preset value, it can be judged whether the current load of the hybrid power system is large or small, so as to judge whether the operating mode of the hybrid power system is the heavy load mode or the light load mode. At the same time, to prevent over-discharging or overcharging of the energy storage module, the magnitude relationship between the current power level of the energy storage module and the power limit value is judged to prevent over-discharging or overcharging of the energy storage module. By distinguishing the operating mode of the hybrid power system, the operating mode of the hybrid power system is determined to control the system in combination with the operating mode of the system, flexibly adjust the power output, protect the energy storage battery, enhance the system reliability, and be able to reduce energy consumption and emissions, achieving efficient utilization of energy.

[0035] S140. When the hybrid power system is in the heavy load mode, control the generator motor to provide power for the hydraulic system; when the hybrid power system is in the light load mode, control the generator motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module.

[0036] Specifically, when the hybrid power system is in the heavy load mode, control the power generation motor to provide power for the hydraulic system to assist the hydraulic system in outputting force, improving the power and reliability of the hydraulic system; when the hybrid power system is in the light load mode, control the power generation motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module, so as to recover the redundant power and improve the energy management, thereby realizing flexible adjustment of the outputs of the engine and the power generation motor according to the actual load demand, making the power distribution more reasonable, enhancing the system reliability, and being able to reduce energy consumption and emissions, achieving efficient utilization of energy.

[0037] It should be noted that the control method of the hybrid power system in the embodiment of the present invention is applicable to various heavy machinery and equipment that require a high-efficiency and environmentally friendly rotary system drive, with a wide application range, which can reduce the energy consumption and emissions of the heavy machinery and equipment and achieve efficient utilization of energy.

[0038] The embodiment of the present invention provides a control method for a hybrid power system. By obtaining the required power of the hydraulic system, the required power of the electric drive rotary system, and the current power of the energy storage module, calculate the total required power of the system according to the required power of the hydraulic system and the required power of the electric drive rotary system; then, according to the size relationship between the total required power and the first preset value, and the size relationship between the current power of the energy storage module and the power limit value, distinguish the working modes of the hybrid power system, determine the working mode of the hybrid power system, and control the system in combination with the working mode of the system to flexibly adjust the power output; when the hybrid power system is in the heavy load mode, control the power generation motor to provide power for the hydraulic system to assist the hydraulic system in outputting force, improving the power and reliability of the hydraulic system; when the hybrid power system is in the light load mode, control the power generation motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module, so as to recover the redundant power and improve the energy management. The present invention can flexibly adjust the outputs of the engine and the power generation motor according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, and be able to reduce energy consumption and emissions, achieving efficient utilization of energy.

[0039] The embodiment of the present invention also provides another control method for a hybrid power system. Figure 2 As shown in the flowchart of another control method for a hybrid power system provided by the embodiment of the present invention, Figure 2 the control method of the hybrid power system includes:

[0040] S210. Obtain the required power of the hydraulic system, the required power of the electric drive rotary system, and the current power of the energy storage module.

[0041] S220. Calculate the total required power of the system according to the required power of the hydraulic system and the required power of the electric drive rotary system.

[0042] S230. When the total demand power is greater than the first preset value and the current power of the energy storage module is greater than the discharge power limit value, it is determined that the hybrid power system is in the heavy load mode; when the total demand power is less than or equal to the first preset value and the current power of the energy storage module is less than the charge power limit value, it is determined that the hybrid power system is in the light load mode.

[0043] Specifically, when the total demand power is greater than the first preset value, it indicates that the current load of the hybrid power system is large. However, in the heavy load mode, the energy storage module needs to supply power to the generator motor so that the generator motor provides power for the hydraulic system. Therefore, it is necessary to determine whether the current power of the energy storage module is greater than the discharge power limit value. If so, it can be determined that the operating mode of the hybrid power system is the heavy load mode. Similarly, when the total demand power is less than the first preset value, it indicates that the current load of the hybrid power system is small. Since the energy storage module needs to be charged in the light load mode, it is necessary to determine whether the current power of the energy storage module is less than the charge power limit value. If so, it can be determined that the operating mode of the hybrid power system is the light load mode. By distinguishing the operating mode of the hybrid power system and further determining the operating mode of the hybrid power system through the current power of the energy storage module, the system can be controlled in combination with the operating mode of the system, further preventing overcharging or over-discharging of the energy storage battery, enhancing the reliability of the system, reducing energy consumption and emissions, and achieving efficient utilization of energy.

[0044] S240. When the hybrid power system is in the heavy load mode, control the generator motor to provide power for the hydraulic system according to the preset output curve; when the hybrid power system is in the light load mode, control the generator motor to convert part of the kinetic energy generated by the engine into electric energy according to the preset power generation curve to charge the energy storage module.

[0045] Among them, the preset output curve and the preset power generation curve can be set in advance. The preset output curve and the preset power generation curve can be obtained through pre-tests. The generator motor has an electric mode and a power generation mode. When the generator motor is in the electric mode, the generator motor provides power for the hydraulic system according to the preset output curve. When the generator motor is in the power generation mode, the generator motor converts part of the kinetic energy generated by the engine into electric energy according to the preset power generation curve to charge the energy storage module.

[0046] Specifically, when the hybrid power system is in the heavy load mode, the power generation motor is controlled to provide power for the hydraulic system according to a preset output curve to assist the hydraulic system in outputting power, so as to achieve precise control of the auxiliary output process, and improve the power and reliability of the hydraulic system; when the hybrid power system is in the light load mode, the power generation motor is controlled to convert part of the kinetic energy generated by the engine into electric energy according to a preset power generation curve to charge the energy storage module, so as to achieve precise control of the power generation process, further recover the redundant power, and further improve the energy management, thereby realizing flexible adjustment of the outputs of the engine and the power generation motor according to the actual load demand, making the power distribution more reasonable, enhancing the system reliability, and being able to reduce energy consumption and emissions, and realizing efficient utilization of energy.

[0047] In some embodiments of the present invention, the energy storage module may also be a battery pack, a liquid hydrogen battery, an ammonia fuel cell, etc. The energy storage module may be a set or multiple discrete sets.

[0048] Optionally, obtaining the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module includes:

[0049] S310. Obtain the operation control signal of the hydraulic system, the slewing control signal of the electric drive slewing system, the load pressure of the hydraulic system, and the current power of the energy storage module; wherein, the operation control signal of the hydraulic system includes at least one of a boom control signal, a bucket control signal, an arm control signal, a left travel control signal, and a right travel control signal.

[0050] Wherein, an excavator is usually provided with a left handle, a right handle, and a pair of pedals. Both the left handle and the right handle have two degrees of freedom, including the front-back degree of freedom and the left-right degree of freedom. The left travel control signal and the right travel control signal can be generated by a pair of pedals, and can respectively control the left travel and the right travel of the excavator. The right handle can generate a boom control signal and a bucket control signal, and the left handle can generate an arm control signal and a slewing control signal. The driver can control the opening degree and operation direction of the left handle, the right handle, and a pair of pedals according to the current working scenario and load, to generate a boom control signal, a bucket control signal, an arm control signal, a left travel control signal, a right travel control signal, and a slewing control signal. The boom control signal, the bucket control signal, the arm control signal, the left travel control signal, the right travel control signal, and the slewing control signal include the opening degree information of the left handle, the right handle, and a pair of pedals.

[0051] Specifically, the boom control signal, the bucket control signal, the arm control signal, the left travel control signal, the right travel control signal, and the slewing control signal can be obtained by obtaining the opening degree information of the left handle, the right handle, and a pair of pedals of the excavator. The load pressure of the hydraulic system can be obtained from the pressure sensor of the excavator, and the current power of the energy storage module can be obtained from the energy storage module.

[0052] S320. Calculate the required flow rate of the hydraulic system according to the operation control signal of the hydraulic system and the preset flow rate definition curve, and calculate the required power of the hydraulic system based on the required flow rate of the hydraulic system and the load pressure of the hydraulic system.

[0053] Specifically, different openings of the handle or foot pedal in the preset flow rate definition curve correspond to different pump flow rates. Therefore, the corresponding pump flow rates can be obtained according to the preset flow rate definition curve and the opening of the handle or foot pedal. Thus, the corresponding pump flow rates can be obtained respectively according to the boom control signal, bucket control signal, arm control signal, left travel control signal, right travel control signal, and swing control signal. The sum of the pump flow rates corresponding to the boom control signal, bucket control signal, arm control signal, left travel control signal, and right travel control signal is the required flow rate of the hydraulic system. After obtaining the required flow rate of the hydraulic system and the load pressure of the hydraulic system, according to the power calculation formula of the hydraulic pump, the required power of the hydraulic system can be calculated based on the required flow rate of the hydraulic system and the load pressure of the hydraulic system. Exemplarily, the power calculation formula of the hydraulic pump is: P = Q × p ÷ (600 × η), where P is the required power of the hydraulic system (unit: kilowatt), Q is the required flow rate of the hydraulic system (unit: liter per minute), p is the load pressure of the hydraulic system (unit: megapascal), and η is the total efficiency of the pump. The total efficiency of the hydraulic pump is usually between 60% and 80%, which reflects the energy loss situation of the pump during operation. By calculating the required power of the hydraulic system based on the required flow rate of the hydraulic system and the load pressure of the hydraulic system, it is convenient to judge the working mode of the hybrid power system.

[0054] S330. Determine the required power of the electric drive swing system according to the swing control signal of the electric drive swing system.

[0055] Specifically, the required power of the electric drive swing system is the total power of the swing motor in the electric drive swing system. The power of the swing motor can be calculated by the speed and torque of the swing motor in the electric drive swing system. Different openings of the handle in the swing control signal of the electric drive swing system correspond to different required speeds and required torques of the swing motor. Combining the power calculation formula of the swing motor, the required power of the electric drive swing system can be calculated through the required speed and required torque. By obtaining the required power of the hydraulic system, the required power of the electric drive swing system, and the current power of the energy storage module, the total required power of the system can be calculated based on the required power of the hydraulic system and the required power of the electric drive swing system. Through the total required power, the working mode of the system can be judged, so as to be able to flexibly adjust the output of the engine and the generator motor according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, and be able to reduce energy consumption and emissions, and achieve efficient utilization of energy.

[0056] Figure 3 It is a flowchart of yet another control method for a hybrid power system provided by an embodiment of the present invention, as Figure 3As shown, after the excavator where the hybrid power system is located enters the normal mode, it is determined whether there is a request to cut off the high voltage when the whole vehicle of the excavator stops, that is, it is determined whether the excavator is working in a high-voltage environment. If so, the control process ends. If not, the real-time opening of the boom handle is obtained, the real-time opening of the arm handle is obtained, the real-time opening of the bucket handle is obtained, the real-time opening of the left travel pedal is obtained, and the real-time opening of the right travel pedal is obtained. Then, the total required flow rate is calculated according to the defined curve of the handle opening and the flow rate. Then, the pressure sensing value of the pressure sensor of the main pump is obtained, which can be used as the load pressure of the hydraulic system. Then, the total required power of the hydraulic system is calculated according to the pressure and the total required flow rate, that is, the required power of the hydraulic system. Then, according to the total required power of the hydraulic system and the total required power of the electric drive slewing system, the total required power of the whole machine is calculated. Then, the total required power of the whole machine is obtained, the switching power target value between the heavy load mode and the light load mode is set, and the switching power target value is the first preset value. And the power limit value of the super capacitor for auxiliary output is set, that is, the discharge limit value. It is determined whether the actual total required power is greater than the switching power target value. If so, it is further determined whether the power of the super capacitor is less than the power limit value. If not, the current power of the super capacitor is collected, the upper limit value of the power of the super capacitor is set, that is, the charging power limit value, and it is determined whether the power of the super capacitor is less than the upper limit value. When it is determined whether the power of the super capacitor is less than the power limit value, if not, it is determined that the hybrid power system is in the heavy load mode, and the generator motor is controlled to assist the engine output with a preset output curve. If so, the process returns to the step of obtaining the total required power of the whole machine. When it is determined whether the power of the super capacitor is less than the upper limit value, if so, when it is determined to be in the light load mode, the generator motor is controlled to convert part of the kinetic energy generated by the engine into electric energy according to the set curve to charge the energy storage module. If not, the process returns to the step of obtaining the total required power of the whole machine. In the control method of the hybrid power system in the embodiment of the present invention, the real-time required total flow rate is obtained by using a statistical algorithm according to the real-time opening of the handle, and the system pressure is monitored in real time by using a pressure sensor, so as to calculate the total required power of the real-time system. Then, the real-time power of the engine and the generator motor is dynamically allocated in combination with the change of the power of the energy storage system. Although the existing hybrid excavators can achieve a certain optimization of power output through the coordinated work of the engine and the motor, because they mostly adopt a control method based on the system speed for a single-parameter power distribution method, they cannot dynamically adjust the working mode according to the actual working requirements, load conditions, and the change of the power of the energy storage system. This method results in inaccurate calculation of the required power in some working conditions, too large deviation in load estimation, inability to dynamically adjust the working mode according to the change of the power of the energy storage system, the hybrid system cannot work in the efficient area, and when the load fluctuates greatly, the speed of the hybrid system fluctuates greatly, the energy-saving effect is poor, and the system reliability is affected.Compared with the existing technical solutions, the control method of the embodiment of the present invention can improve the responsiveness of the hybrid power system; the hybrid power system can operate in the efficient region under complex working conditions, optimize the power performance of the system, enhance the adaptability and operation efficiency of the excavator under different working conditions, reduce the rotational speed fluctuation of the hybrid power system, enhance the system reliability, reduce energy consumption and emissions, and achieve efficient utilization of energy.

[0057] The embodiment of the present invention also provides another control method for a hybrid power system. Figure 4 It is a flowchart of the control method for the energy storage module in the hybrid power system provided by the embodiment of the present invention. As Figure 4 shown, it includes:

[0058] S410. Determine the state of charge of the energy storage module according to the current power of the energy storage module.

[0059] Among them, the energy storage system in a hybrid excavator generally consists of the following core components: internal combustion engine, electric motor, energy storage module (such as lithium battery or supercapacitor), energy management unit (Energy Management Unit, EMU), etc. Among them, the internal combustion engine mainly provides continuous power output, and the electric motor provides auxiliary power or recovers braking energy as needed. The energy storage system stores kinetic energy through the energy storage module and adjusts the output power of the electric motor through a control strategy. Due to the adoption of a hybrid power system, the energy storage system cannot be configured with a large-capacity battery or supercapacitor as the energy storage module; due to the working condition characteristics of the hybrid excavator, continuous large-load changes and periodic heavy-light load conversions, the energy storage system has been in a state of high-power charging or discharging. At this time, the current of the energy storage system is very large and the current fluctuation is very large, resulting in extremely inaccurate estimation of the remaining power (State of Charge, abbreviated as SOC) based on current; the traditional SOC estimation algorithm will cause the hybrid power system to be extremely unstable, and the system frequently switches between the charging and discharging states, resulting in low efficiency of the energy storage system and reduced reliability and life. Therefore, the available capacity of the energy storage module is optimized and partitioned, and corresponding control strategies are adopted for different regions to realize energy storage and release, improve the effective energy storage of the energy storage module, improve the efficiency of the energy storage system, and improve the reliability and life of the energy storage module.

[0060] Specifically, the state of charge of the energy storage module can be divided according to the remaining power of the energy storage module. Then, the state of charge of the energy storage module can be determined according to the current power of the energy storage module, so as to monitor and manage the charging and discharging process of the energy storage module in real time, and ensure the safety and efficient operation of the energy storage module.

[0061] Optionally, when the current power of the energy storage module is in the first power region, determine the state of charge of the energy storage module as the full charge region; when the current power of the energy storage module is in the second power region, determine the state of charge of the energy storage module as the near full charge region; when the current power of the energy storage module is in the third power region, determine the state of charge of the energy storage module as the charge limit region; when the current power of the energy storage module is in the fourth power region, determine the state of charge of the energy storage module as the optimal charge region; when the current power of the energy storage module is in the fifth power region, determine the state of charge of the energy storage module as the optimal discharge region; when the current power of the energy storage module is in the sixth power region, determine the state of charge of the energy storage module as the discharge limit region; when the current power of the energy storage module is in the seventh power region, determine the state of charge of the energy storage module as the near discharge region; when the current power of the energy storage module is in the eighth power region, determine the state of charge of the energy storage module as the discharge region.

[0062] Among them, the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region, and the eighth power region are adjacent, and the power of the energy storage module in the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region, and the eighth power region decreases in turn.

[0063] Specifically, Figure 5 is a schematic diagram of the state of charge division of the energy storage module provided by the embodiment of the present invention. As Figure 5 shown, in order to improve the charging and discharging efficiency and reliability of the energy storage module, according to the characteristics of the energy storage module itself, the inside of the energy storage module is divided into 8 regions, namely: the optimal charge region, the optimal discharge region, the charge limit region, the discharge limit region, the near full charge region, the near discharge region, the full charge region, and the discharge region. In the optimal charge and discharge regions, the supercapacitor can charge and discharge at full power; in the charge and discharge limit regions, the charging and discharging power are limited; in the near full charge and discharge regions, the charging and discharging power are further limited; in the full charge and discharge regions, the supercapacitor stops charging and discharging.

[0064] In addition, the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region, and the eighth power region are adjacent, and the power of the energy storage modules in the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region, and the eighth power region decreases in sequence. Exemplarily, the first power region is the region where the current power of the energy storage module is between 95% and 100%, the second power region is the region where the current power of the energy storage module is between 90% and 95%, the third power region is the region where the current power of the energy storage module is between 85% and 90%, the fourth power region is the region where the current power of the energy storage module is between 50% and 85%, the fifth power region is the region where the current power of the energy storage module is between 15% and 50%, the sixth power region is the region where the current power of the energy storage module is between 10% and 15%, the seventh power region is the region where the current power of the energy storage module is between 5% and 10%, and the eighth power region is the region where the current power of the energy storage module is between 0% and 5%.

[0065] S420. Control the charge and discharge process of the energy storage module according to the state of charge of the energy storage module.

[0066] Specifically, controlling the charge and discharge process of the energy storage module according to the state of charge of the energy storage module. For example, under different states of charge of the energy storage module, restricting or not restricting the charge and discharge process of the energy storage module can ensure the safety and efficient operation of the battery.

[0067] Optionally, if the energy storage module is in the discharge state and the state of charge of the energy storage module is one of the full charge region, the near full charge region, the charge limit region, the optimal charge region, and the optimal discharge region, then control the energy storage module to discharge according to the required power of the energy storage module; if the energy storage module is in the discharge state and the state of charge of the energy storage module is the discharge limit region or the near discharge region, then control the energy storage module to discharge according to the smaller value between the required power of the energy storage module and the preset discharge limit power; if the energy storage module is in the discharge state and the state of charge of the energy storage module is the discharge region, then control the energy storage module to stop discharging; if the energy storage module is in the charge state and the state of charge of the energy storage module is one of the optimal charge region, the optimal discharge region, the discharge limit region, the near discharge region, and the discharge region, then control the energy storage module to charge according to the required power of the energy storage module; if the energy storage module is in the charge state and the state of charge of the energy storage module is the near full charge region or the charge limit region, then control the energy storage module to charge according to the smaller value between the required power of the energy storage module and the preset charge limit power; if the energy storage module is in the charge state and the state of charge of the energy storage module is the full charge region, then control the energy storage module to stop charging.

[0068] Specifically, by dividing the energy storage module into regions and adopting different control modes for different regions, the energy storage efficiency of the energy storage module can be significantly improved. By controlling the charging and discharging processes of the energy storage module according to the state of charge of the energy storage module, the reliability of the energy storage module can be enhanced. Even when the energy storage module is continuously in a state of high-power charging or discharging due to continuous large-load changes or periodic light-heavy load conversions, the current of the energy storage module will not be very large and the current fluctuation will not be significant. By optimizing the charging and discharging control strategy of the energy storage module, overcharging, over-discharging, and high-frequency rapid charging and discharging are avoided, the aging rate of the energy storage module is reduced, the service life of the battery is significantly extended, and the maintenance and replacement costs are reduced.

[0069] In some embodiments of the present invention, when the hybrid power system is in a heavy-load mode and the power generation motor is controlled to provide power for the hydraulic system with a preset output curve, the charging process of the energy storage module can be controlled according to the state of charge of the energy storage module. At this time, the energy storage module is in a discharging state. If the state of charge of the energy storage module is in one of the full-charge region, near-full-charge region, charging limit region, optimal charging region, and optimal discharging region, the energy storage module is controlled to discharge according to the required power of the energy storage module; if the state of charge of the energy storage module is in the discharging limit region or near-discharged region, the energy storage module is controlled to discharge according to the smaller value between the required power of the energy storage module and the preset discharging limit power; if the state of charge of the energy storage module is in the discharged region, the energy storage module is controlled to stop discharging, thereby preventing over-discharge of the energy storage module and improving the reliability and service life of the energy storage module.

[0070] In some embodiments of the present invention, when the hybrid power system is in a light-load mode, the power generation motor is controlled to convert part of the kinetic energy generated by the engine into electric energy with a preset power generation curve to charge the energy storage module. At this time, the energy storage module is in a charging state, and the charging process of the energy storage module needs to be controlled according to the state of charge of the energy storage module. For example, if the state of charge of the energy storage module is in one of the optimal charging region, optimal discharging region, discharging limit region, near-discharged region, and discharged region, the energy storage module is controlled to charge according to the required power of the energy storage module; if the state of charge of the energy storage module is in the near-full-charge region or charging limit region, the energy storage module is controlled to charge according to the smaller value between the required power of the energy storage module and the preset charging limit power; if the state of charge of the energy storage module is in the full-charge region, the energy storage module is controlled to stop charging, thereby preventing overcharging of the energy storage module, improving the reliability and service life of the energy storage module, and realizing real-time monitoring and management of the charging and discharging processes of the energy storage module to ensure the safety and efficient operation of the energy storage module.

[0071] Figure 6 It is a flowchart of another control method for the energy storage module in the hybrid power system provided by the embodiments of the present invention, as Figure 6As shown, in the embodiment of the present invention, the energy storage module in the hybrid power system is a supercapacitor. After the system starts to work, it is necessary to first check whether there are any faults in the status of the hardware and the system. After confirming that there are no errors, initialization is performed and the working mode is entered. Then, the SOC value of the supercapacitor is obtained, and the current required power of the supercapacitor is obtained. By judging the size relationship between the current SOC value of the supercapacitor and the charging start limit point or the discharging start limit point of the supercapacitor, as well as the size comparison relationship between the actual required power and the charging and discharging limit powers of the supercapacitor, the working mode of the supercapacitor is controlled. It is judged whether the supercapacitor discharges externally. If so, it is judged that the supercapacitor is in the discharging state. If not, it is judged whether the supercapacitor is in the charging state. If the supercapacitor is in the discharging state and the current SOC value of the supercapacitor is greater than the discharging start limit point, the supercapacitor discharges according to the required power. If the current SOC value of the supercapacitor is less than the discharging start limit point, it discharges according to the smaller one of the required power and the limit power. The limit power is the preset discharging limit power. If the supercapacitor triggers a power shortage state, the discharging stops. If the supercapacitor is in the charging state and the current SOC value of the supercapacitor is less than the charging start limit point, the supercapacitor charges according to the required power. If the current SOC value of the supercapacitor is greater than the charging start limit point, it charges according to the smaller one of the required power and the limit power. This limit power is the preset charging limit power. If the supercapacitor triggers a full charge state, the charging stops. The control method of the energy storage module in the hybrid power system provided by the embodiment of the present invention aims to improve the energy utilization efficiency and reliability and extend the battery life. By adopting an energy management strategy with multiple modes in the embodiment of the present invention, according to the required power of the excavator and the SOC value of the supercapacitor, the working mode of the supercapacitor is determined, and then the charging and discharging power of the supercapacitor is determined. By setting the charging power start limit point and the discharging power start limit point, the excessive current fluctuation is prevented, and the stability and reliability of the energy storage system are enhanced. By real-time monitoring the SOC value of the supercapacitor and combining with the real-time required power, the charging and discharging power of the supercapacitor can be accurately adjusted, thereby slowing down the aging of the supercapacitor and extending the service life of the supercapacitor.

[0072] An embodiment of the present invention provides a control method for a hybrid power system. By differentiating the working modes of the hybrid power system, the working mode of the hybrid power system is determined, so as to control the system in combination with the working mode of the system and flexibly adjust the power output. When the hybrid power system is in the heavy load mode, the generator motor is controlled to provide power for the hydraulic system to assist the hydraulic system in outputting force, improving the power and reliability of the hydraulic system. When the hybrid power system is in the light load mode, the generator motor is controlled to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module, so as to recover the redundant power, improve the energy management, and by optimizing the charge and discharge control strategy of the energy storage module, overcharge, over-discharge and high-frequency fast charge and discharge are avoided, the aging speed of the energy storage module is reduced, the service life of the battery is significantly extended, and the maintenance and replacement costs are reduced. The present invention can flexibly adjust the outputs of the engine and the generator motor according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, and can reduce the energy consumption and emissions, realizing the efficient utilization of energy.

[0073] An embodiment of the present invention also provides a hybrid power system. Figure 7 As a structural schematic diagram of a hybrid power system in an embodiment of the present invention, the control module in the hybrid power system in an embodiment of the present invention can execute the control method of the hybrid power system in any embodiment of the present invention to achieve the functions and technical effects of the control method of the hybrid power system in any embodiment of the present invention. As Figure 7 shown, the hybrid power system includes a hydraulic system 110, an electric drive slewing system 120, an energy storage module 130, a generator motor 140 and a control module 150.

[0074] The control module 150 is communicatively connected to the hydraulic system 110, the electric drive slewing system 120, the generator motor 140 and the energy storage module 130 respectively; the energy storage module 130 is electrically connected to the electric drive slewing system 120 and the generator motor 140 respectively.

[0075] The hydraulic system 110 includes an engine 111 and an output module 112, and the output module 112 is powered by the engine 111 and the generator motor 140; the energy storage module 130 supplies power to the electric drive slewing system 120 and the generator motor 140; the generator motor 140 is also used to charge the energy storage module 130.

[0076] The control module 150 is configured to obtain the required power of the hydraulic system 110, the required power of the electric drive slewing system 120, and the current power of the energy storage module 130, and calculate the total required power of the system according to the required power of the hydraulic system 110 and the required power of the electric drive slewing system 120; the control module 150 is further configured to determine the operating mode of the hybrid power system according to the magnitude relationship between the total required power and the first preset value, and the magnitude relationship between the current power of the energy storage module 130 and the power limit value; when the hybrid power system is in the heavy load mode, control the power generation motor 140 to provide power for the hydraulic system 110; when the hybrid power system is in the light load mode, control the power generation motor 140 to convert part of the kinetic energy generated by the engine 111 into electrical energy to charge the energy storage module 130.

[0077] Wherein, the engine 111, the output module 112 and the power generation motor 140 are mechanically connected to realize the power transmission between the engine 111, the output module 112 and the power generation motor 140. The hydraulic system 110 further includes an engine control component (Electronic Engine Control Unit, abbreviated as EECU). The input end of the EECU is communicatively connected to the control module 150 and can receive the control signal of the control module 150. The output end of the EECU is connected to the engine 111. The EECU can control the operation of the engine 111 according to the received control signal of the control module 150. The energy storage module 130 is electrically connected to the electric drive slewing system 120 and the power generation motor 140 respectively to supply power to the electric drive slewing system 120 and the power generation motor 140.

[0078] Specifically, the control module 150 can obtain the required power of the hydraulic system 110, the required power of the electric drive slewing system 120, and the current power level of the energy storage module 130, and calculate the total required power of the system based on the required power of the hydraulic system 110 and the required power of the electric drive slewing system 120, so as to judge the working mode of the system through the total required power and the current power level of the energy storage module. The control module 150 can also determine the working mode of the hybrid power system according to the magnitude relationship between the total required power and the first preset value, and the magnitude relationship between the current power level of the energy storage module 130 and the power limit value. The control module 150 can judge whether the current load of the hybrid power system is large or small according to the magnitude relationship between the total required power and the first preset value, so as to judge whether the working mode of the hybrid power system is a heavy load mode or a light load mode. At the same time, to prevent the energy storage module 130 from over-discharging or over-charging, the magnitude relationship between the current power level of the energy storage module 130 and the power limit value is also judged to prevent the energy storage module 130 from over-discharging or over-charging. By distinguishing the working mode of the hybrid power system, the working mode of the hybrid power system is determined, so as to control the system in combination with the working mode of the system, flexibly adjust the power output, protect the energy storage module 130, enhance the system reliability, and be able to reduce energy consumption and emissions, realizing the efficient utilization of energy.

[0079] The control module 150 can control the working state of the generator motor 140. When the hybrid power system is in the heavy load mode, the control module 150 controls the generator motor 140 to provide power for the hydraulic system 110 to assist the engine 111 in the hydraulic system 110 to output power, improving the power and reliability of the hydraulic system. When the hybrid power system is in the light load mode, the control module 150 controls the generator motor 140 to convert part of the kinetic energy generated by the engine 111 into electric energy to charge the energy storage module 130 to recover the excess power and improve the energy management, so as to flexibly adjust the outputs of the engine 111 and the generator motor 140 according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, and be able to reduce energy consumption and emissions, realizing the efficient utilization of energy.

[0080] An embodiment of the present invention provides a hybrid power system. The control module calculates the total required power of the system according to the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module by obtaining them, and determines the working mode of the hybrid power system according to the relationship between the total required power and the first preset value, as well as the relationship between the current power of the energy storage module and the power limit value, so as to control the system in combination with the working mode of the system and flexibly adjust the power output. When the hybrid power system is in the heavy load mode, the control module controls the generator motor to provide power for the hydraulic system to assist the hydraulic system in outputting force and improve the power and reliability of the hydraulic system. When the hybrid power system is in the light load mode, the control module controls the generator motor to convert part of the kinetic energy generated by the engine into electric energy to charge the energy storage module, so as to recover the redundant power and improve the energy management. The hybrid power system of the present invention can flexibly adjust the output of the engine and the generator motor according to the actual load demand, make the power distribution more reasonable, enhance the system reliability, reduce the energy consumption and emissions, and realize the efficient utilization of energy.

[0081] Figure 8 FIG. is a schematic structural diagram of another hybrid power system in the embodiment of the present invention, as Figure 8 shown. In the hybrid power system, the output module 112 includes a power take-off box 1121, a first hydraulic pump 1122, and a second hydraulic pump 1123. The input end of the power take-off box 1121 is mechanically connected to the engine 111, the auxiliary end of the power take-off box 1121 is mechanically connected to the generator motor 140, the first output end of the power take-off box 1121 is mechanically connected to the first hydraulic pump 1122, and the second output end of the power take-off box 1121 is mechanically connected to the second hydraulic pump 1123.

[0082] The power take-off box 1121 is used to distribute the power generated by the engine 111 and the generator motor 140 to the first hydraulic pump 1122 and the second hydraulic pump 1123 when the hybrid power system is in the heavy load mode. The power take-off box 1121 is also used to distribute the power generated by the engine 111 to the generator motor 140, the first hydraulic pump 1122, and the second hydraulic pump 1123 when the hybrid power system is in the light load mode, so that the generator motor 140 can convert part of the kinetic energy generated by the engine 111 into electric energy to charge the energy storage module 130.

[0083] Specifically, the first hydraulic pump 1122 and the second hydraulic pump 1123 can be further connected to the moving components. For example, the first hydraulic pump 1122 and the second hydraulic pump 1123 can be connected to components such as the boom, bucket, arm, and crawler of an excavator to achieve the movement of components such as the boom, bucket, arm, and crawler. The power divider 1121 can distribute the power generated by the engine 111 and the motor-generator 140 to the first hydraulic pump 1122 and the second hydraulic pump 1123 when the hybrid system is in the heavy-load mode, thereby improving the power, making the power distribution more reasonable in the heavy-load mode, with small torque impact, small system speed fluctuation, and high reliability. The power divider 1121 is also used to distribute the power generated by the engine 111 to the motor-generator 140, the first hydraulic pump 1122, and the second hydraulic pump 1123 when the hybrid system is in the light-load mode, so that the motor-generator 140 can convert part of the kinetic energy generated by the engine 111 into electrical energy to charge the energy storage module 130, avoiding energy waste, further realizing the energy recovery process, reducing energy consumption and emissions, and achieving efficient utilization of energy.

[0084] Continue to refer to Figure 8 , operating the right handle, left handle, and a pair of foot pedals in the excavator can respectively obtain a boom control signal, a bucket control signal, an arm control signal, a swing control signal, a left travel control signal, and a right travel control signal. The control module 150 calculates the required power of the hydraulic system 110 and the required power of the electric drive swing system 120 by acquiring the boom control signal, the bucket control signal, the arm control signal, the swing control signal, the left travel control signal, and the right travel control signal.

[0085] Continue to refer to Figure 8, the electric drive slewing system 120 includes a slewing motor controller 121 and multiple slewing motors 122. The slewing motor controller 121 is electrically connected to the multiple slewing motors 122. The energy storage module 130 includes a battery unit 131 and a power distribution unit 132 (Power Distribution Unit, PDU). The battery unit 131 and the power distribution unit 132 are electrically connected. The power distribution unit 132 is electrically connected to the slewing motor controller 121. The power distribution unit 132 is also connected to the generator motor 140 through the generator motor controller 160. The power distribution unit 132 can distribute electric energy to the generator motor 140 and the electric drive slewing system 120. The control module 150 is connected to the generator motor 140 through the generator motor controller 150. The generator motor controller 160 can control the operation of the generator motor 140. The current power of the energy storage module 130 can be obtained from the battery unit 131. The battery unit 131 can be a supercapacitor, a battery, etc. A battery management system (Battery Management System, BMS) can also be provided in the battery unit 131 to obtain the current power of the energy storage module 130.

[0086] It should be noted that the control module 150 in the embodiments of the present invention can execute the control method of the hybrid power system in any embodiment of the present invention to achieve the functions and technical effects of the control method of the hybrid power system in any embodiment of the present invention.

[0087] The embodiments of the present invention provide a hybrid power system. The control module differentiates the working modes of the hybrid power system to determine the working modes of the hybrid power system, and controls the system in combination with the working modes of the system to flexibly adjust the power output. When the hybrid power system is in the heavy load mode, the control module controls the generator motor to provide power for the hydraulic system to assist the hydraulic system in outputting power, improving the power and reliability of the hydraulic system. When the hybrid power system is in the light load mode, the control module controls the generator motor to convert part of the kinetic energy generated by the engine into electric energy to charge the energy storage module to recover the excess power and improve the energy management. The hybrid power system of the present invention can flexibly adjust the outputs of the engine and the generator motor according to the actual load requirements, make the power distribution more reasonable, enhance the system reliability, and can reduce energy consumption and emissions to achieve the efficient utilization of energy.

[0088] The embodiments of the present invention also provide a hybrid excavator, including the hybrid power system in the above embodiments, thereby achieving the same functions and technical effects as the hybrid power system in the above embodiments.

[0089] Note that the above is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments here, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A control method for a hybrid power system, characterized in that, The hybrid power system includes a hydraulic system and an electric drive slewing system. The hydraulic system is powered by an engine and a motor-generator. The electric drive slewing system and the motor-generator are powered by an energy storage module. The control method includes: Obtaining the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module; Calculating the total required power of the system according to the required power of the hydraulic system and the required power of the electric drive slewing system; Determining the working mode of the hybrid power system according to the magnitude relationship between the total required power and a first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value; wherein, the working mode includes a heavy load mode and a light load mode; When the hybrid power system is in the heavy load mode, controlling the motor-generator to provide power for the hydraulic system; when the hybrid power system is in the light load mode, controlling the motor-generator to convert part of the kinetic energy generated by the engine into electric energy to charge the energy storage module.

2. The control method of the hybrid power system according to claim 1, wherein The determining the working mode of the hybrid power system according to the magnitude relationship between the total required power and a first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value includes: When the total required power is greater than the first preset value and the current power of the energy storage module is greater than the discharge power limit value, determining that the hybrid power system is in the heavy load mode; When the total required power is less than or equal to the first preset value and the current power of the energy storage module is less than the charge power limit value, determining that the hybrid power system is in the light load mode.

3. The control method of the hybrid power system according to claim 1, characterized in that When the hybrid power system is in the heavy load mode, controlling the motor-generator to provide power for the hydraulic system; when the hybrid power system is in the light load mode, controlling the motor-generator to convert the kinetic energy generated by the engine into electric energy to charge the energy storage module includes: When the hybrid power system is in the heavy load mode, controlling the motor-generator to provide power for the hydraulic system according to a preset output curve; When the hybrid power system is in the light load mode, controlling the motor-generator to convert part of the kinetic energy generated by the engine into electric energy according to a preset power generation curve to charge the energy storage module.

4. The control method of the hybrid power system according to claim 1, wherein The obtaining the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module includes: Obtaining the operation control signal of the hydraulic system, the slewing control signal of the electric drive slewing system, the load pressure of the hydraulic system, and the current power of the energy storage module; wherein, the operation control signal of the hydraulic system includes at least one of a boom control signal, a bucket control signal, an arm control signal, a left travel control signal, and a right travel control signal; Calculating the required flow rate of the hydraulic system according to the operation control signal of the hydraulic system and a preset flow rate definition curve, and calculating the required power of the hydraulic system according to the required flow rate of the hydraulic system and the load pressure of the hydraulic system; Determine the required power of the electric drive slewing system corresponding to the slewing control signal of the electric drive slewing system.

5. The control method of the hybrid power system according to claim 1, characterized in that, After determining the operating mode of the hybrid power system, it further includes: Determine the state of charge of the energy storage module according to the current power of the energy storage module; Control the charge and discharge process of the energy storage module according to the state of charge of the energy storage module.

6. The control method of the hybrid power system according to claim 5, characterized in that, Determine the state of charge of the energy storage module according to the current power of the energy storage module, including: When the current power of the energy storage module is in the first power region, determine that the state of charge of the energy storage module is the full charge region; When the current power of the energy storage module is in the second power region, determine that the state of charge of the energy storage module is the near full charge region; When the current power of the energy storage module is in the third power region, determine that the state of charge of the energy storage module is the charge limit region; When the current power of the energy storage module is in the fourth power region, determine that the state of charge of the energy storage module is the optimal charge region; When the current power of the energy storage module is in the fifth power region, determine that the state of charge of the energy storage module is the optimal discharge region; When the current power of the energy storage module is in the sixth power region, determine that the state of charge of the energy storage module is the discharge limit region; When the current power of the energy storage module is in the seventh power region, determine that the state of charge of the energy storage module is the near discharge region; When the current power of the energy storage module is in the eighth power region, determine that the state of charge of the energy storage module is the discharge region; Wherein, the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region and the eighth power region are adjacent, and the power of the energy storage module in the first power region, the second power region, the third power region, the fourth power region, the fifth power region, the sixth power region, the seventh power region and the eighth power region decreases in sequence.

7. The control method of the hybrid power system according to claim 6, characterized in that, The control of the charge and discharge process of the energy storage module according to the state of charge of the energy storage module includes: If the energy storage module is in a discharge state and the state of charge of the energy storage module is one of the full charge region, the near full charge region, the charge limit region, the optimal charge region, and the optimal discharge region, control the energy storage module to discharge according to the required power of the energy storage module; If the energy storage module is in a discharge state and the state of charge of the energy storage module is the discharge limit region or the near discharge region, control the energy storage module to discharge according to the smaller value of the required power of the energy storage module and the preset discharge limit power; If the energy storage module is in a discharge state and the state of charge of the energy storage module is the discharge region, control the energy storage module to stop discharging; If the energy storage module is in a charging state and the state of charge of the energy storage module is in one of the optimal charging region, the optimal discharging region, the discharging limit region, the near - depleted region, and the depleted region, control the energy storage module to charge according to the required power of the energy storage module; If the energy storage module is in a charging state and the state of charge of the energy storage module is in the near - full region or the charging limit region, control the energy storage module to charge according to the smaller value between the required power of the energy storage module and a preset charging limit power; If the energy storage module is in a charging state and the state of charge of the energy storage module is in the full region, control the energy storage module to stop charging.

8. A hybrid power system, characterized in that, The hybrid power system includes a hydraulic system, an electric drive slewing system, an energy storage module, a generator - motor, and a control module; The control module is communicatively connected to the hydraulic system, the electric drive slewing system, the generator - motor, and the energy storage module respectively; the energy storage module is electrically connected to the electric drive slewing system and the generator - motor respectively; The hydraulic system includes an engine and a power output module, and the power output module is powered by the engine and the generator - motor; the energy storage module supplies power to the electric drive slewing system and the generator - motor; the generator - motor is also used to charge the energy storage module; The control module is used to obtain the required power of the hydraulic system, the required power of the electric drive slewing system, and the current power of the energy storage module, and calculate the total required power of the system according to the required power of the hydraulic system and the required power of the electric drive slewing system; the control module is also used to determine the working mode of the hybrid power system according to the magnitude relationship between the total required power and a first preset value, and the magnitude relationship between the current power of the energy storage module and the power limit value; when the hybrid power system is in a heavy - load mode, control the generator - motor to provide power for the hydraulic system; when the hybrid power system is in a light - load mode, control the generator - motor to convert part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module.

9. The hybrid system according to claim 8, wherein, The power output module includes a transfer case, a first hydraulic pump, and a second hydraulic pump; The input end of the transfer case is mechanically connected to the engine, the auxiliary end of the transfer case is mechanically connected to the generator - motor, the first output end of the transfer case is mechanically connected to the first hydraulic pump, and the second output end of the transfer case is mechanically connected to the second hydraulic pump; The transfer case is used to distribute the power generated by the engine and the generator - motor to the first hydraulic pump and the second hydraulic pump when the hybrid power system is in the heavy - load mode; the transfer case is also used to distribute the power generated by the engine to the generator - motor, the first hydraulic pump, and the second hydraulic pump when the hybrid power system is in the light - load mode, so that the generator - motor converts part of the kinetic energy generated by the engine into electrical energy to charge the energy storage module.

10. A hybrid excavator, comprising the hybrid power system according to any one of claims 8-9.

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