Low-voltage power distribution control method for electric loader

Abstract

The invention discloses a low-voltage power distribution control method for an electric loader, which belongs to the technical field of electric loaders and comprises the following steps of: S1, establishing a load power supply priority system, and dividing a steering system, a braking system and a working device of the electric loader into three levels of power supply priorities; s2, a current sensor is adopted to monitor the current state of each load branch in real time; s3, a solid-state intelligent switching system is constructed through an MOSFET array, switching control over a load circuit is achieved, and the switching time is shorter than 2 ms; according to the invention, a solid-state intelligent switching system is constructed by adopting an MOSFET array to replace a traditional mechanical relay, the switching time is less than 2ms, the service life reaches 500,000 times, the problem of contact adhesion in a vibration environment is thoroughly solved by combining a dual-channel redundancy layout, and the failure probability of the relay is reduced by 40%; the hierarchical design of the master control layer, the power layer and the communication layer of the intelligent distribution box realizes multi-channel load independent management and fault isolation, and power supply of other loads is not affected when a certain branch has a fault.

Description

Technical Field

[0001] This invention belongs to the field of electric loader technology, specifically, it relates to a low-voltage power distribution control method for electric loaders. Background Technology

[0002] As a core piece of construction machinery in projects such as construction engineering, mining, and ports, loaders are undergoing a power system transformation towards electrification in response to increasingly stringent national environmental protection and carbon emission requirements. Traditional fuel-powered loaders, powered by internal combustion engines, suffer from low efficiency and severe pollution, while electric loaders have become the mainstream development due to their zero emissions and high energy efficiency. However, with the penetration rate of new energy construction machinery exceeding 30%, the technical shortcomings of traditional low-voltage power distribution systems are becoming increasingly apparent, mainly in the following aspects: Insufficient reliability: Traditional low-voltage power distribution relies on mechanical relays to achieve load switching, but in the high-frequency vibration working environment of loaders, mechanical contacts are prone to sticking, with a failure rate as high as 18%, which seriously affects operational safety. Poor load adaptability: Load fluctuations are large during loader operation (such as hydraulic pump start-up, steering operation, etc.). Traditional power distribution systems lack dynamic adjustment mechanisms, resulting in voltage fluctuations exceeding ±15%, which affects the lifespan of sensitive electronic equipment. Battery protection is too simple: Overcharge and over-discharge protection of batteries only relies on voltage threshold judgment, without considering key parameters such as internal resistance and temperature. This can easily lead to battery life reduction or safety risks due to misjudgment. Low system integration: The functions of power distribution, motor drive, and cooling are designed separately, resulting in complex wiring harnesses and a large number of hardware components, which not only increases costs but also reduces system response speed. Delayed fault response: The lack of localized diagnostics and redundant protection mechanisms results in long fault detection and handling times, which may lead to safety accidents in extreme cases.

[0003] Therefore, in order to meet the reliability, energy efficiency and intelligence requirements of the low-voltage power distribution system of electric loaders, there is an urgent need for a control method that integrates dynamic load management, multi-dimensional safety protection and efficient energy distribution. Summary of the Invention

[0004] In response to the problems raised in the prior art, the present invention provides a low-voltage power distribution control method for electric loaders.

[0005] To solve the above problems, the present invention adopts the following technical solution.

[0006] A low-voltage power distribution control method for an electric loader includes the following steps: Step S1: Establish a load power supply priority system, and divide the steering system, braking system and working device of the electric loader into three levels of power supply priority; Step S2, real-time monitoring of the current state of each load branch is performed using a current sensor; Step S3, a MOSFET array is used to construct a solid-state intelligent switching system, so as to realize switching control of the load circuit, and the switching time is less than 2 ms; Step S4, a battery health model integrating voltage, internal resistance and temperature is constructed, so as to predict the remaining capacity of the battery; Step S5, when the electric loader is powered on, line impedance detection and solid-state switching system state verification are completed, wherein the line impedance detection threshold is 0.3Ω; Step S6, during the working phase of the electric loader, the load power priority is dynamically adjusted according to the working condition, when the hydraulic pump is started, the current of the auxiliary system is automatically limited to 10A; after detecting a short circuit fault, the fault circuit is cut off within 20 ms, and the standby power supply is activated.

[0007] Preferably, the prediction error of the battery health model for the remaining capacity of the battery is less than 5%.

[0008] Further, it also includes dynamically adjusting the speed and torque of the hydraulic motor: when steering or working, the speed and torque of the hydraulic motor are increased to quickly respond to the demand; when not working, the hydraulic motor is controlled to run at a low idle speed.

[0009] Preferably, it also includes hydraulic system overflow valve control: the hydraulic motor consumes excess battery capacity through hydraulic system overflow valve control to avoid overcharging of the battery.

[0010] Further, when realizing the switching control of the load circuit, an intelligent power distribution box is designed in layers, the intelligent power distribution box includes a master control layer, a power layer and a communication layer, independent management and fault isolation of multiple channels of loads are realized, and the failure probability of the relay is reduced by 40%.

[0011] Further, when dynamically realizing the load priority system and monitoring the state, the vehicle controller, the battery management system and the regional controller are cooperated based on the CAN bus network, the voltage and current parameters are collected in real time, the load priority is dynamically adjusted, and the fault response time is shortened to within 50 ms.

[0012] Further, the CAN bus network adopts a double-CAN communication channel design, and automatically switches to the backup channel when the main channel fails, and starts an emergency steering pump to ensure operation safety when the steering fails.

[0013] Preferably, when managing the battery health, an integrated all-in-one controller is used, the all-in-one controller integrates battery management, motor drive and cooling system control functions, combines the cooling pipelines of the battery cooling and the cab air conditioner, and reduces the number of hardware and the complexity of the wiring harness.

[0014] Preferably, in step S6, an integrated low-voltage power supply redundancy mechanism is adopted, and the high-voltage power supply conditioning module is connected in parallel with the low-voltage power supply to ensure that the key controller can still perform safety protection actions when power is cut off.

[0015] Preferably, in step S6, when fault diagnosis is performed, localized fault diagnosis is realized through the edge computing layer, and when abnormal current or temperature is detected, the fuse and contactor are triggered for hierarchical protection.

[0016] Compared with the prior art, the application has the following beneficial effects: 1. The application improves power supply reliability, adopts a MOSFET array to build a solid-state intelligent switching system to replace a traditional mechanical relay, the switching time is less than 2 ms, the service life is up to 500,000 times, and the double-channel redundancy layout is combined to completely solve the problem of contact adhesion in a vibrating environment, so that the failure probability of the relay is reduced by 40%; the layered design of the “main control layer + power layer + communication layer” of the intelligent power distribution box realizes independent management and fault isolation of multiple channels of loads, and the power supply of other loads is not affected when a branch fails.

[0017] 2. The application establishes a three-level power supply priority system for steering, braking and working devices, preferentially guarantees the power supply of key loads during operation, and automatically reduces the power of auxiliary systems during non-operation; through dynamic adjustment of the speed / torque of the hydraulic motor, the energy consumption is reduced by more than 20%; in combination with the control of the overflow valve of the hydraulic system, the excess power of the battery is consumed by the hydraulic motor to avoid the risk of overcharging.

[0018] 3. The application builds a battery health model integrating three parameters of voltage, internal resistance and temperature, uses a Kalman filtering algorithm to realize residual capacity prediction, and the error is less than 5%, overcoming the limitations of traditional voltage threshold judgment; an integrated low-voltage power supply redundancy mechanism (high-voltage conditioning module connected in parallel with low-voltage battery) is adopted to ensure that the key controller can still perform safety protection actions when power is cut off.

[0019] 4. The application realizes cooperation of VCU, BMS and regional controllers based on a double-CAN bus network, realizes real-time acquisition of voltage and current parameters and dynamic adjustment of load priority, and shortens the fault response time to within 50 ms; the regional controller integrates edge computing functions to realize localized fault diagnosis and hierarchical protection (fuse and contactor linkage), and the short-circuit fault processing time is controlled within 20 ms. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 FIG. 1 is a structural schematic diagram of a power distribution box based on a semiconductor device according to the application; Fig. 2 FIG. 2 is a physical connection schematic diagram of a CAN bus according to the application; Fig. 3 FIG. 3 is a control logic state diagram according to the application. DETAILED DESCRIPTION

[0021] So that the purposes, technical solutions and advantages of the embodiments of the present application are more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. Embodiments

[0023] As Figs. 1-3 shown, a low-voltage power distribution control method for an electric loader includes the following steps in specific implementation: Step S1, establishing a load power supply priority system: Based on the work safety and functional necessity of the electric loader, the loads are divided into three power supply priorities, and the priority rules are preset in the VCU control logic: First priority: steering system (including steering motor and steering angle sensor), to ensure the continuity of travel direction control; Second priority: brake system (including electric proportional brake valve and brake pressure sensor), to ensure brake safety; Third priority: working device (including hydraulic pump and shovel drive motor) and auxiliary system (including cab air conditioner and lighting equipment).

[0024] Priority dynamic adjustment logic: during work (first and second priority loads are guaranteed to be powered at full power, and third priority loads are distributed power according to working condition requirements; during non-work, the power of third priority loads is automatically reduced to reduce energy consumption.

[0025] Step S2, real-time monitoring of load branch current state: Current sensors (measurement accuracy ±1%, response time <5ms) are connected in series in the key load branches such as steering, braking, hydraulic pump and auxiliary system, and real-time acquisition of branch current data is performed. The sensor output signal is transmitted to the regional controller after filtering processing, and the regional controller analyzes the data every 10ms to determine whether there are overcurrent, undercurrent or current mutation abnormalities, and synchronously transmits the monitoring data to the VCU and battery management system (BMS) through the CAN bus, to provide basis for load priority adjustment and fault diagnosis.

[0026] Step S3, constructing a solid-state intelligent switching system: MOSFET array is used to replace the traditional electromagnetic relay to build a solid-state intelligent switching system, which is integrated into the power layer of the intelligent power distribution box to realize the non-contact on-off control of the load circuit. Hardware selection: MOSFET devices with a withstand voltage of 100V and a conduction resistance of ≤8mΩ are selected, and a high-speed drive chip is used to ensure that the switching time is <2ms. Switching logic: VCU sends PWM control signals to the drive chip according to the load priority instructions, and the drive chip amplifies the signals to control the MOSFET conduction / cutoff, completing the switching of the load power supply. Reliability design: MOSFET array uses dual-channel redundant layout, and when a single device fails, it automatically switches to the standby channel to avoid load power failure and solve the problem of contact sticking of traditional mechanical relays in a vibrating environment.

[0027] Step S4, build a multi-dimensional battery health model To solve the problem of traditional storage batteries relying only on voltage threshold to judge over-discharge, a battery health (SOH) model is built by integrating voltage, internal resistance, and temperature three parameters to realize accurate remaining capacity (SOC) prediction: Parameter collection: Real-time collection of battery voltage, total internal resistance (measured by AC injection method, error <2%), and cell temperature (collected by 8 NTC sensors, range -40℃-85℃) through BMS; Model algorithm: Kalman filter algorithm is used to integrate three parameter data to establish the mapping relationship between SOH and SOC, the formula is:

[0028] Among them, is the initial capacity, is the real-time current, is the charging and discharging efficiency, is the rated capacity, is dynamically corrected by voltage-internal resistance-temperature matrix; Accuracy verification: Through experimental test, the prediction error of the model for the remaining capacity is <5%, which can effectively avoid the risk of overcharging and overdischarging.

[0029] Step S5: power-on self-test process When the electric loader is powered on, the system automatically performs line and device state verification to ensure that the initial state of the power distribution system is normal: Line impedance detection: VCU injects a 12V test voltage through the solid-state intelligent switching system to each load branch, collects the loop current and calculates the impedance (impedance=voltage / current), if the detection value>0.3Ω, it is determined that the line has poor contact, and immediately triggers an audible and light alarm and records the fault code; Solid-state switching system verification: VCU sends on / off instructions to each MOSFET branch in turn, and judges whether the switching function is normal through the current sensor feedback signal. If there is no current change in a branch, it is marked as a fault and the standby channel is started; Self-checking pass condition: When all test items meet the threshold requirements, VCU sends "allow power supply" instruction to BMS, and the system enters standby state, waiting for operation instruction.

[0030] Step S6, dynamic control and fault response in operation stage: Working condition adaptive load control: Based on real-time working condition, dynamically adjust the load power supply strategy to realize efficient energy distribution: Hydraulic pump start-up scenario: When the pressure sensor detects a hydraulic pump start-up signal, VCU sends a current limiting instruction to the auxiliary system controller through CAN bus, limiting the maximum current of auxiliary systems such as air conditioning and lighting to 10A, to prioritize the power demand of the hydraulic pump; Steering / operation scenario: Through the steering angle sensor (accuracy ±1°) and operation mode switch signal, VCU dynamically adjusts the hydraulic motor parameters - when steering or operating, increase the motor speed to 1500 rpm and torque to 80 N・m to quickly respond to demand; When not operating, control the motor to run at a low idle speed of 800 rpm, which can reduce energy consumption by more than 20% according to actual measurement; Battery overcharge protection: When BMS detects that the battery SOC is greater than or equal to 95%, VCU sends a command to the hydraulic system overflow valve controller to increase the opening degree of the overflow valve by 10%, and the excess power (about 500W) is consumed through the hydraulic motor idle cycle to avoid battery overcharge.

[0031] Fault rapid response mechanism: For short circuit, communication interruption and other faults, a multi-level protection and emergency handling process is established: Short circuit fault handling: When the current sensor detects that the branch current is greater than 100A (short circuit characteristic) at a moment, the regional controller transmits the fault signal to the VCU within 10ms, and the VCU sends the off instruction within 10ms after receiving it. The solid-state intelligent switching system cuts off the fault circuit within 20ms, and activates the standby power supply (12V battery pack) to ensure continuous power supply for primary / secondary loads such as steering and braking; Communication redundancy protection: CAN bus uses dual-channel design, with the main channel responsible for regular data transmission and the standby channel for real-time monitoring; When the main channel loses 3 consecutive frames of data or has a check error, the system automatically switches to the standby channel within 50ms; If the steering system communication is interrupted (judged as steering failure), the emergency steering pump (power 1.5kW) is started immediately to ensure operation safety; Localized fault diagnosis: The area controller integrates edge computing functions to analyze current and temperature data in real time. In case of minor abnormalities, it triggers the fuse hierarchical protection (such as blowing the corresponding branch fuse when the auxiliary system is overcurrent). In case of severe abnormalities, it cuts off the main contactor with a response time of <50ms.

[0032] It should be noted that, in practical implementation, the intelligent power distribution box adopts a three-layer architecture of "main control layer + power layer + communication layer" to achieve independent load management and fault isolation. Main control layer: integrates MCU chip, responsible for parsing VCU instructions, executing load priority logic and fault diagnosis; Power layer: Includes MOSFET array and fuse (rated current 50A) to achieve power switching and overcurrent protection; Communication layer: Integrated CAN transceiver supports real-time data interaction with VCU and BMS. This design reduces the probability of relay failure by 40%.

[0033] All-in-one controller integration: Integrating the PDU power distribution unit, motor controller, and cooling system controller into one unit simplifies the system structure. Functional integration: Battery management, motor drive, and cooling control are linked through internal SPI communication, improving response speed by 30%; Hardware optimization: The cooling pipes for battery cooling and cab air conditioning have been merged, reducing pipe length by 2m, hardware quantity by 15%, and wiring harness complexity by 20%.

[0034] Low-voltage power supply redundancy mechanism: In the power supply circuits of key components such as VCU and motor controller, a high-voltage power conditioning module (380V to 12V) is used to supply power in parallel with a 12V low-voltage battery: under normal operating conditions, the two work together to output power. When the low-voltage battery is de-energized, the high-voltage conditioning module seamlessly switches power supply to ensure that the key controller can still perform safety protection actions when power is off.

[0035] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A low-voltage power distribution control method for an electric loader, characterized in that, Includes the following steps: Step S1: Establish a load power supply priority system, and divide the steering system, braking system and working device of the electric loader into three levels of power supply priority; Step S2: Use a current sensor to monitor the current status of each load branch in real time; Step S3: Construct a solid-state intelligent switching system using a MOSFET array to achieve switching control of the load circuit, with a switching time of <2ms; Step S4: Construct a battery health model that integrates three parameters: voltage, internal resistance, and temperature, and predict the remaining battery capacity. Step S5: When the electric loader is powered on, complete the line impedance detection and solid-state switching system status verification, wherein the line impedance detection threshold is 0.3Ω; Step S6: During the operation of the electric loader, the load power supply priority is dynamically adjusted according to the working conditions. When the hydraulic pump starts, the auxiliary system current is automatically limited to 10A. After a short circuit fault is detected, the fault circuit is cut off within 20ms and the backup power supply is activated.

2. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: The battery health model has a prediction error of less than 5% for the remaining battery power.

3. The low-voltage power distribution control method for an electric loader according to claim 2, characterized in that: It also includes dynamically adjusting the speed and torque of the hydraulic motor: increasing the speed and torque of the hydraulic motor to quickly respond to demands during steering or operation; and controlling the hydraulic motor to maintain a low idling speed when not in operation.

4. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: It also includes hydraulic system relief valve control: the hydraulic system relief valve controls the hydraulic motor to consume excess battery power, thus preventing the battery from being overcharged.

5. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: When implementing load circuit switching control, a layered design of intelligent power distribution box is adopted. The intelligent power distribution box includes a main control layer, a power layer and a communication layer, which realizes independent management and fault isolation of multi-channel loads, reducing the probability of relay failure by 40%.

6. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: In the dynamic implementation and status monitoring of the load priority system, the vehicle controller, battery management system and regional controller are coordinated based on the CAN bus network, and voltage and current parameters are collected in real time to dynamically adjust the load priority, and the fault response time is shortened to within 50ms.

7. The low-voltage power distribution control method for an electric loader according to claim 6, characterized in that: The CAN bus network adopts a dual CAN communication channel design. When the main channel fails, it automatically switches to the backup channel, and when steering fails, the emergency steering pump is activated to ensure operational safety.

8. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: When managing battery health, an integrated all-in-one controller is used. This controller integrates battery management, motor drive and cooling system control functions, and combines the cooling pipes of battery cooling and cab air conditioning, reducing the number of hardware and wiring harness complexity.

9. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: In step S6, a low-voltage power supply redundancy mechanism is integrated, which connects the high-voltage power supply conditioning module in parallel with the low-voltage power supply to ensure that the critical controller can still perform safety protection actions when the power is off.

10. The low-voltage power distribution control method for an electric loader according to claim 1, characterized in that: During fault diagnosis in step S6, localized fault diagnosis is achieved through the edge computing layer. When abnormal current or temperature is detected, the fuse and contactor are triggered for graded protection.

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