Electric slewing braking system and control method therefor

Abstract

An electric slewing braking system and a control method therefor. The electric slewing braking system comprises: an electric slewing unit, used for generating regenerative braking energy during electric slewing braking; a power battery unit, used for consuming, when charging is allowed, the regenerative braking energy generated by the electric slewing unit for charging and energy storage; an ISG motor unit, used for consuming, when exhaust braking is allowed, the regenerative braking energy generated by the electric slewing unit to drive an engine unit and a hydraulic unit, and consuming, when exhaust braking is not allowed, the regenerative braking energy generated by the electric slewing unit to drive the hydraulic unit; a braking resistor unit and a whole machine electric accessory unit, used for consuming the regenerative braking energy generated by the electric slewing unit; and a power distribution unit, used for transmitting the regenerative braking energy generated by the electric slewing unit to the power battery unit, the ISG motor unit, the braking resistor unit and the whole machine electric accessory unit. The electric slewing braking system can reduce the loss of the regenerative braking energy and improve the utilization rate of the regenerative electric energy, thereby achieving an energy saving effect.

Description

An electric slewing brake system and a control method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering machinery, and in particular to an electric slewing brake system and a control method thereof. BACKGROUND

[0002] A conventional excavator uses an engine as a power source, uses hydraulic medium, and uses hydraulic energy as a driving source to drive an actuator. However, the hydraulic device is often accompanied by problems such as energy loss, and in particular, the hydraulic slewing device has large rotational inertia, and a large amount of energy is lost on the valve port of the hydraulic valve during rotation and braking, which not only wastes energy, but also causes the hydraulic system to heat up and the service life of components to decrease. In order to reduce such energy loss, a motor-driven slewing system, that is, electric slewing, has gradually emerged. The electric slewing uses an electric motor to replace a hydraulic motor, drives a slewing device through a speed reducer, and realizes the slewing movement of the engineering machinery, thereby reducing energy loss. However, with the gradual application of electric slewing, related problems also arise. In particular, for an electric slewing excavator that exists in a frequent slewing operation scenario, when the battery is in a low-temperature and full-power state, in order to ensure the normal braking function, the problem of high cost and low regeneration energy utilization rate of the braking resistor installed power.

[0003] SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art, and provides an electric slewing brake system and a control method thereof, which solve the technical problems of high cost and low regeneration energy utilization rate of the existing electric slewing brake system.

[0005] To achieve the above-mentioned purpose, the present application is implemented by using the following technical solutions:

[0006] In a first aspect, the present application provides an electric slewing brake system, comprising:

[0007] An electric slewing unit for generating braking regenerative electric energy during electric slewing braking;

[0008] A power battery unit for consuming the braking regenerative electric energy generated by the electric slewing unit to charge and store energy under allowed charging conditions, and not charging and storing energy under unallowed charging conditions;

[0009] An ISG motor unit for consuming the braking regenerative electric energy generated by the electric slewing unit to drive an engine unit and a hydraulic unit under allowed exhaust braking conditions, and consuming the braking regenerative electric energy generated by the electric slewing unit to drive the hydraulic unit under unallowed exhaust braking conditions;

[0010] A braking resistor unit and a whole-machine electrical accessory unit for consuming the braking regenerative electric energy generated by the electric slewing unit;

[0011] A power distribution unit is electrically connected with the electric rotary unit, the power battery unit, the ISG motor unit, the brake resistor unit and the whole machine electrical accessory unit respectively, and is configured to transmit the brake regenerative power generated by the electric rotary unit to the power battery unit, the ISG motor unit, the brake resistor unit and the whole machine electrical accessory unit.

[0012] Optionally, the condition for allowing charging is that the battery temperature is within a preset temperature threshold range, the battery SOC state is lower than a preset state threshold, and the whole machine has no fault alarm.

[0013] The receiving of the brake regenerative power generated by the electric rotary unit includes: taking the minimum value of the current regenerative power of the electric rotary unit and the maximum charging power of the power battery unit as the actual charging power of the power battery unit.

[0014] Optionally, the priority order of consuming the brake regenerative power generated by the electric rotary unit is:

[0015] The power battery unit, the whole machine electrical accessory unit, the ISG motor unit and the brake resistor unit.

[0016] Optionally, the condition for allowing exhaust braking is that the sum of the hydraulic unit demand power and the exhaust braking power is less than or equal to the current regenerative power of the electric rotary unit.

[0017] Optionally, the electric rotary unit includes:

[0018] A rotary motor controller connected with the power distribution unit through high-voltage wires and low-voltage wires;

[0019] A rotary motor connected with the rotary motor controller through high-voltage wires;

[0020] A speed reduction mechanism mechanically connected with the rotary motor;

[0021] A rotary mechanism mechanically connected with the speed reduction mechanism;

[0022] The power battery unit includes:

[0023] A BMS connected with the power distribution unit through high-voltage wires and low-voltage wires;

[0024] A power battery connected with the BMS through high-voltage wires;

[0025] The ISG motor unit includes:

[0026] An ISG motor controller connected with the power distribution unit through high-voltage wires and low-voltage wires;

[0027] ISG motor, connected with the ISG motor controller through high-voltage wire;

[0028] The brake resistor unit comprises:

[0029] The brake resistor controller is connected with the power distribution unit through high-voltage wire and low-voltage wire;

[0030] The brake resistor is connected with the brake resistor controller through high-voltage wire;

[0031] The whole machine electrical accessory unit is connected with the power distribution unit through high-voltage wire and low-voltage wire.

[0032] Optionally, the engine unit comprises:

[0033] The engine is mechanically connected with the ISG motor;

[0034] The engine controller is connected with the engine through signal wire and connected with the power distribution unit through low-voltage wire;

[0035] The hydraulic unit comprises:

[0036] The hydraulic pump is mechanically connected with the ISG motor;

[0037] The hydraulic pump controller is connected with the hydraulic pump through signal wire and connected with the power distribution unit through low-voltage wire.

[0038] Optionally, the electric rotary braking system further comprises a whole machine controller, which is connected with the power distribution unit, the rotary motor controller, the whole machine electrical accessory unit, the BMS, the hydraulic controller, the engine controller and the brake resistor controller through signal wire respectively; the whole machine controller is further connected with the power distribution unit through low-voltage wire.

[0039] Optionally, the regenerative power P1 of the electric rotary unit is: P1=ω×T×η

[0040] Under the condition of allowing charging: P1=P2+P3+P4+P5 P5=P6+P7

[0041] Under the condition of not allowing charging: P1=P3+P4+P5

[0042] In the formula, ω, T and η are the rotating speed, braking torque and efficiency factor of the rotary motor, P2 is the charging power of the power battery unit, P3, P4 and P5 are the consumed powers of the whole machine electrical accessory unit, the brake resistor unit and the ISG motor unit respectively, and P6 and P7 are the consumed powers of the engine unit and the hydraulic unit respectively.

[0043] In a second aspect, the present application provides a control method of an electric rotary braking system, which adopts the electric rotary braking system as described above, and the control method comprises:

[0044] In response to the electric rotary braking, braking regenerative electric energy is generated by the electric rotary unit;

[0045] In response to the satisfaction of the allowed charging condition, the braking regenerative electric energy is transmitted to the power battery unit by the power distribution unit for charging and energy storage;

[0046] In response to the dissatisfaction of the allowed charging condition, the braking regenerative electric energy is transmitted to the whole-machine electrical accessory unit by the power distribution unit;

[0047] In response to the satisfaction of the whole-machine electrical accessory unit and still having remaining braking regenerative electric energy, the current remaining braking regenerative electric energy is transmitted to the ISG motor unit by the power distribution unit;

[0048] In response to the satisfaction of the ISG motor unit and still having remaining braking regenerative electric energy, the current remaining braking regenerative electric energy is transmitted to the braking resistor unit by the power distribution unit.

[0049] Optionally, in response to the satisfaction of the allowed exhaust braking condition, the ISG motor unit drives the engine unit and the hydraulic unit;

[0050] In response to the dissatisfaction of the allowed exhaust braking condition, the ISG motor unit drives the hydraulic unit.

[0051] Compared with the prior art, the present application has the following beneficial effects:

[0052] The electric rotary braking system and the control method thereof provided by the present application combine the electric rotary unit with the power battery unit, the whole-machine electrical accessory unit, the whole-machine hybrid power unit (the ISG motor unit, the engine unit, the hydraulic unit) and the braking resistor unit to form the electric rotary braking system, so as to ensure sufficient braking force and improve the safety of the whole machine, and to reduce the installed power of the braking resistor and the cost. The method firstly recovers and then reuses and finally consumes the rotary braking regenerative electric energy. When the electric energy is generated by the rotary braking, it is firstly determined whether the energy storage is allowed according to the fault state of the whole machine and the state of the power battery. If the energy storage is allowed, the energy recovery is performed according to the real-time obtained energy storage power. Otherwise, the whole-machine electrical accessory unit and the hydraulic unit are reused. Finally, the engine exhaust braking consumption and the braking resistor consumption are considered. The present application reduces the consumption of the braking regenerative electric energy, improves the utilization rate of the regenerative electric energy, and achieves the energy-saving effect. BRIEF DESCRIPTION OF DRAWINGS

[0053] Fig. 1 is a structural block diagram of the electric rotary braking system provided by the embodiment of the present application;

[0054] Fig. 2 is an energy distribution diagram of the electric rotary braking system provided by the embodiment of the present application;

[0055] Fig. 3 is a flow chart of a control method of the electric rotary braking system according to an embodiment of the present application. DETAILED DESCRIPTION

[0056] The application will be further described below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0057] Example 1

[0058] As shown in Figs. 1 and 2, the application provides an electric rotary braking system, which comprises an electric rotary unit, a power battery unit, an ISG motor unit, an engine unit, a hydraulic unit, a braking resistor unit, a whole-machine electrical accessory unit and a power distribution unit. The power distribution unit is electrically connected with the electric rotary unit, the power battery unit, the ISG motor unit, the braking resistor unit and the whole-machine electrical accessory unit, and is used to transmit the braking regenerative electric energy generated by the electric rotary unit to the power battery unit, the ISG motor unit, the braking resistor unit and the whole-machine electrical accessory unit.

[0059] The electric rotary unit is used to generate braking regenerative electric energy during electric rotary braking. The electric rotary unit comprises a rotary motor controller, a rotary motor, a speed reduction mechanism and a rotary mechanism. The rotary motor controller is connected with the power distribution unit through high-voltage wires and low-voltage wires, and is used for energy transmission. The rotary motor controller is connected with the rotary motor through high-voltage wires, and is used for rotary motor control. The speed reduction mechanism is mechanically connected with the rotary motor, and is used for rotary mechanism driving. The rotary mechanism is mechanically connected with the speed reduction mechanism, and is used for speed reduction and torque increase to transmit power. The rotary mechanism is used to bear an upper working device.

[0060] The power battery unit is used to consume the braking regenerative electric energy generated by the electric rotary unit to charge and store energy under the condition of allowing charging. The power battery unit does not charge and store energy under the condition of not allowing charging.

[0061] The power battery unit comprises a BMS and a power battery. The BMS is connected with the power distribution unit through high-voltage wires and low-voltage wires. The power battery is connected with the BMS through high-voltage wires. The power battery is used to store energy for the whole electric rotary braking system, and is used for braking electric energy recovery. The BMS is used to control charging and discharging of the power battery, and is used to monitor and feedback battery key information and state.

[0062] Specifically, in the embodiment, the condition of allowing charging is that the battery temperature is within a preset temperature threshold range, the battery SOC state is lower than a preset state threshold, and the whole machine has no fault alarm. In order to ensure the safety and stability of the charging process, the minimum value of the current regenerative power of the electric rotary unit and the maximum charging power of the power battery unit is taken as the actual charging power of the power battery unit.

[0063] ISG motor unit, for consuming brake regenerative power generated by the electric slewing unit to drive the engine unit and the hydraulic unit in the exhaust brake allowed condition; for consuming brake regenerative power generated by the electric slewing unit to drive the hydraulic unit in the exhaust brake not allowed condition; the ISG motor unit comprises: an ISG motor controller and an ISG motor, the ISG motor controller is connected with the power distribution unit through high-voltage wires and low-voltage wires; the ISG motor is connected with the ISG motor controller through high-voltage wires; the ISG motor is installed at the end of the engine, for converting slewing brake regenerative power into mechanical energy; the ISG motor controller is used for controlling the ISG motor, monitoring and feeding back the state information of the ISG motor.

[0064] Specifically in the embodiment: the exhaust brake allowed condition is that the sum of the hydraulic unit demand power and the exhaust brake power is less than or equal to the current regenerative power of the electric slewing unit.

[0065] The engine unit comprises: an engine and an engine controller, the engine is mechanically connected with the ISG motor; the engine controller is connected with the engine through signal wires and connected with the power distribution unit through low-voltage wires; the hydraulic unit comprises: a hydraulic pump and a hydraulic pump controller, the hydraulic pump is mechanically connected with the ISG motor; the hydraulic pump controller is connected with the hydraulic pump through signal wires and connected with the power distribution unit through low-voltage wires. On common engineering machinery, the hydraulic unit usually further comprises a hydraulic valve, a traveling motor, a boom hydraulic cylinder, a stick hydraulic cylinder and a bucket hydraulic cylinder; the hydraulic pump is installed at the other end of the ISG motor, for converting the converted mechanical energy into hydraulic energy consumption; the hydraulic valve is installed at the rear end of the hydraulic pump, for controlling the hydraulic oil circuit; the hydraulic working device is connected with the hydraulic valve through the hydraulic pipeline, for realizing the working action; the hydraulic working device comprises the boom hydraulic cylinder, the stick hydraulic cylinder, the bucket hydraulic cylinder and the traveling motor; the hydraulic controller is connected with the hydraulic pump and the hydraulic valve, for collecting the hydraulic pump pressure flow parameters and controlling the hydraulic valve.

[0066] A brake resistance unit and a whole machine electrical accessory unit, for consuming brake regenerative power generated by the electric slewing unit; the brake resistance unit comprises: a brake resistance controller and a brake resistance, the brake resistance controller is connected with the power distribution unit through high-voltage wires and low-voltage wires; the brake resistance is connected with the brake resistance controller through high-voltage wires; the brake resistance controller is used for controlling the brake resistance to consume power, ensuring sufficient braking force and making the slewing brake safe and smooth; the brake resistance is used for consuming slewing brake regenerative power. The whole machine electrical accessory unit is connected with the power distribution unit through high-voltage wires and low-voltage wires.

[0067] The electric rotary braking system further comprises a whole machine controller connected with the power distribution unit, the rotary motor controller, the whole machine electrical accessory unit, the BMS, the hydraulic controller, the engine controller and the brake resistor controller through signal lines; the whole machine controller is further connected with the power distribution unit through a low-voltage wire.

[0068] The whole machine controller preferentially regulates the storage of the power battery, then regulates the whole machine electrical accessory, the engine exhaust brake and the hydraulic system consumption, and finally regulates the brake resistor device consumption according to the obtained relevant information.

[0069] The regenerative power P1 of the electric rotary unit is: P1=ω×T×η

[0070] In the condition of allowing charging: P1=P2+P3+P4+P5 P5=P6+P7

[0071] In the condition of not allowing charging: P1=P3+P4+P5

[0072] In the formula, ω, T and η are the rotating speed, braking torque and efficiency factor of the rotary motor, P2 is the charging power of the power battery unit, P3, P4 and P5 are the consumption powers of the whole machine electrical accessory unit, the brake resistor unit and the ISG motor unit respectively, and P6 and P7 are the consumption powers of the engine unit and the hydraulic unit respectively.

[0073] Embodiment two:

[0074] The application provides a control method of an electric rotary braking system, which adopts the electric rotary braking system as described above, and the control method comprises the following steps:

[0075] Step S1: generating braking regenerative electric energy through an electric rotary unit in response to electric rotary braking.

[0076] Step S2, in response to meeting the allowed charging condition, brake regenerative electric energy is transmitted to the power battery unit through the power distribution unit for charging energy storage.

[0077] Step S3, in response to not meeting the allowed charging condition, brake regenerative electric energy is transmitted to the whole machine electrical accessory unit through the power distribution unit.

[0078] Step S4, in response to meeting the whole machine electrical accessory unit still has remaining brake regenerative electric energy, the current remaining brake regenerative electric energy is transmitted to the ISG motor unit through the power distribution unit.

[0079] In response to meeting the allowed exhaust brake condition, the ISG motor unit drives the engine unit and the hydraulic unit;

[0080] In response to not meeting the allowed exhaust brake condition, the ISG motor unit drives the hydraulic unit.

[0081] Step S5, in response to meeting the ISG motor unit still has remaining brake regenerative electric energy, the current remaining brake regenerative electric energy is transmitted to the brake resistance unit through the power distribution unit.

[0082] The actual operation process on site is shown in FIG. 3, including:

[0083] Step one: power battery energy storage, storing regenerative electric energy by the vehicle-mounted power battery;

[0084] Step two: whole machine electrical accessory consumption, consumed by the whole machine electrical accessory;

[0085] Step three: whole machine hybrid power system consumption, consumed by the hydraulic system in the form of hydraulic energy and the mechanical energy form consumed by the engine exhaust brake;

[0086] Step four: brake resistance consumption, consumed by the brake resistance in the form of heat energy.

[0087] Power battery energy storage includes the following steps:

[0088] S101, the regenerative brake electric energy generated by the rotary motor is judged whether the power battery is allowed to charge according to the battery temperature, SOC state and whole machine fault state;

[0089] Among them, the battery temperature, SOC state and whole machine fault state are allowed to charge the power battery when they are met at the same time:

[0090] Condition a1, the battery temperature is within a preset threshold range;

[0091] Condition a2, the battery SOC state is lower than the preset threshold;

[0092] Condition a3, the whole machine has no fault alarm;

[0093] S102, if the power battery allows charging, then the regenerative power of the rotary motor and the maximum charging power of the battery are calculated in real time according to the rotation speed and torque of the rotary motor, and the smaller one is taken as the energy storage power after comparison;

[0094] S103, if the power battery does not allow charging, then the whole machine electrical accessory consumption stage is directly performed.

[0095] The whole machine electrical accessory consumption includes the following steps:

[0096] S201, when there is still surplus regenerative braking electric energy after satisfying the power storage power of the power battery, or when the battery is fully charged during the power storage stage of the power battery;

[0097] S202, then the surplus regenerative braking electric energy is directly transmitted to the whole machine electrical accessory consumption.

[0098] The whole machine hybrid power system consumption includes the following steps:

[0099] S301, when there is still surplus regenerative braking electric energy after satisfying the whole machine electrical accessory consumption;

[0100] S302, then whether the engine exhaust brake is allowed is judged according to the hydraulic system demand power, the surplus regenerative power and the engine exhaust brake power obtained by real-time calculation;

[0101] S303, if the engine exhaust brake is allowed, then the surplus regenerative braking electric energy is directly transmitted to the ISG motor for driving the hydraulic pump and the engine exhaust brake consumption;

[0102] S304, if the engine exhaust brake is not allowed, then the surplus regenerative braking electric energy is directly transmitted to the ISG motor for driving the hydraulic pump consumption.

[0103] The braking resistor consumption is performed when there is still surplus regenerative braking electric energy after completing the whole machine hybrid power system consumption, and the surplus regenerative braking electric energy is consumed in the form of heat energy through the braking resistor.

[0104] Those skilled in the art will understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0105] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0106] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0108] The above only is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the technical principles of the present application, can also make a number of improvements and variations, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. An electric rotary braking system, characterized in that, include: An electric slewing unit is used to generate regenerative braking energy during electric slewing braking. The power battery unit is used to charge and store energy by consuming the regenerative braking energy generated by the electro-rotation unit under charging conditions; and not to charge and store energy under charging conditions. The ISG motor unit is used to drive the engine unit and hydraulic unit by consuming the regenerative braking energy generated by the electric rotary unit when exhaust braking is permitted; and to drive the hydraulic unit by consuming the regenerative braking energy generated by the electric rotary unit when exhaust braking is not permitted. The braking resistor unit and the overall electrical accessory unit are used to consume the braking regenerative electrical energy generated by the electric rotary unit; The power distribution unit is electrically connected to the electric rotary unit, the power battery unit, the ISG motor unit, the braking resistor unit, and the overall electrical accessory unit, respectively, and is used to transfer the regenerative braking energy generated by the electric rotary unit to the power battery unit, the ISG motor unit, the braking resistor unit, and the overall electrical accessory unit.

2. The electric slewing braking system according to claim 1, characterized in that, The permitted charging conditions are: the battery temperature is within a preset temperature threshold range, the battery SOC state is lower than a preset state threshold, and the whole machine has no fault alarms. The process of receiving the regenerative braking power generated by the electric slewing unit includes taking the minimum value between the current regenerative power of the electric slewing unit and the maximum charging power of the power battery unit as the actual charging power of the power battery unit.

3. The electric slewing braking system according to claim 1, characterized in that, The priority order for consuming the regenerative braking energy generated by the electric rotary unit is as follows: Power battery unit, complete machine electrical accessory unit, ISG motor unit and braking resistor unit.

4. The electric slewing braking system according to claim 1, characterized in that, The condition for allowing exhaust braking is that the sum of the power required by the hydraulic unit and the power required for exhaust braking is less than or equal to the current regenerative power of the electric rotary unit.

5. The electric slewing braking system according to claim 1, characterized in that, The electric rotary unit includes: The rotary motor controller is connected to the power distribution unit via high-voltage and low-voltage wires; A rotary motor is connected to the rotary motor controller via a high-voltage wire; The reduction mechanism is mechanically connected to the rotary motor; The slewing mechanism is mechanically connected to the reduction mechanism; The power battery unit includes: The BMS is connected to the power distribution unit via high-voltage and low-voltage wires; The power battery is connected to the BMS via a high-voltage wire; The ISG motor unit includes: The ISG motor controller is connected to the power distribution unit via high-voltage and low-voltage wires; The ISG motor is connected to the ISG motor controller via a high-voltage wire; The braking resistor unit includes: The braking resistor controller is connected to the power distribution unit via high-voltage and low-voltage wires; The braking resistor is connected to the braking resistor controller via a high-voltage wire; The electrical accessory unit of the whole machine is connected to the power distribution unit via high-voltage wires and low-voltage wires.

6. The electric slewing braking system according to claim 5, characterized in that, The engine unit includes: The engine is mechanically connected to the ISG motor; The engine controller is connected to the engine via a signal line and to the power distribution unit via a low-voltage wire; The hydraulic unit includes: The hydraulic pump is mechanically connected to the ISG motor; The hydraulic pump controller is connected to the hydraulic pump via a signal line and to the power distribution unit via a low-voltage wire.

7. The electric slewing braking system according to claim 6, characterized in that, The electric slewing braking system also includes a machine controller, which is connected to the power distribution unit, the slewing motor controller, the machine electrical accessory unit, the BMS, the hydraulic controller, the engine controller, and the braking resistor controller via signal lines; the machine controller is also connected to the power distribution unit via a low-voltage wire.

8. The electric slewing braking system according to claim 6, characterized in that, The regenerative power P1 of the electric rotary unit is: P1=ω×T×η Under permissible charging conditions: P1 = P2 + P3 + P4 + P5 P5 = P6 + P7 Under conditions where charging is not permitted: P1 = P3 + P4 + P5 In the formula, ω, T, and η are the rotational speed, braking torque, and efficiency factor of the rotary motor, P2 is the charging power of the power battery unit, P3, P4, and P5 are the power consumption of the electrical accessory unit, braking resistor unit, and ISG motor unit of the whole machine, respectively, and P6 and P7 are the power consumption of the engine unit and hydraulic unit, respectively.

9. A control method for an electric slewing braking system, characterized in that, The control method of the electric slewing braking system as described in any one of claims 1-8 includes: In response to electric slewing braking, regenerative braking energy is generated through the electric slewing unit; In response to meeting the permissible charging conditions, the regenerative braking energy is transferred to the power battery unit for charging and energy storage through the power distribution unit. In response to the failure to meet the permissible charging conditions, the regenerative braking energy is transferred to the electrical accessory unit of the whole machine through the power distribution unit; In response to the fact that there is still residual regenerative braking energy after satisfying the electrical accessory units of the whole machine, the current residual regenerative braking energy is transferred to the ISG motor unit through the power distribution unit; In response to the fact that there is still residual regenerative braking energy after the ISG motor unit is satisfied, the current residual regenerative braking energy is transferred to the braking resistor unit through the power distribution unit.

10. The control method for the electric slewing braking system according to claim 9, characterized in that, In response to meeting the permissible exhaust braking conditions, the ISG motor unit drives the engine unit and the hydraulic unit; In response to the failure to meet the permissible exhaust braking conditions, the ISG motor unit drives the hydraulic unit.

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