Method for evaluating gradeability of hybrid power loader with super capacitor

Abstract

The invention belongs to the technical field of hybrid power supplies. The invention discloses a method for evaluating the gradeability of a hybrid power loader with a super capacitor. The method comprises the following steps: S1, charging a power battery and the super capacitor of the hybrid power loader until the power battery and the super capacitor are nearly fully charged; s2, the hybrid power loader starts to advance; s3, detecting whether the traction force when the hybrid power loader advances at a constant speed is greater than a or not, and if the traction force is greater than a, executing S4; if the traction force is less than a, executing S5; s4, whether the power battery reaches the specified maximum output current b or not is detected, and if yes, the gradeability of the hybrid power loader is strong; s5, whether the power battery reaches the specified maximum output current b in the advancing process or not is detected, and if the output current is b, the step S6 is executed; and S6, the loading machine is jointly driven by the super capacitor and the power battery, in this way, if the traction force is larger than a, the climbing ability requirement is met. The gradeability verification efficiency of the hybrid power loader with the super capacitor can be improved, and gradeability evaluation conditions are simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of hybrid power supply, and in particular relates to a method for evaluating the gradeability of a hybrid loader with a supercapacitor. Background Art

[0002] With the continuous rise in fossil energy prices and the pursuit of the dual carbon goals of carbon compliance and carbon neutrality, construction machinery such as loaders are bound to undergo a new energy revolution such as hybrid power. The domestic loader industry is currently dominated by pure fuel-powered loaders. Loaders powered by hybrid energy composed of power batteries and supercapacitors are still in the research stage. Hybrid loaders have not been mass-produced and put into market use. The industry has not developed a suitable climbing grade evaluation method for the complex power output form of hybrid loaders. This is a blank area that urgently needs to be filled.

[0003] Prior art Chinese invention patent CN113267350A discloses a hybrid forklift climbing performance evaluation method, comprising the following steps: S1, start the hybrid forklift; S2, detect the speed of the hybrid forklift; 3, detect whether the battery power is greater than c%, if the battery power is greater than c%, the climbing ability requirement is met, otherwise the climbing performance is too strong; S4, detect whether the battery power is greater than c%, if the battery power is greater than c%, the climbing ability is insufficient, if the battery power is not greater than c%, execute S5;

[0004] S5, the forklift stops by braking on the ramp, and then charges the battery, while checking the battery power of the forklift. If the power is less than d%, continue charging, and if the power is greater than d%, execute S6; S6, release the brake, the hybrid forklift starts climbing again, and checks the vehicle speed. If the vehicle speed is greater than b, the climbing ability requirement is met, otherwise the climbing ability is insufficient, which can solve the problem of complex changes in the power output of the hybrid forklift. The existing climbing performance tests are all based on outdoor ramps, and data collection is inconvenient during the test. For example, the maximum ramp slope test of the forklift is very difficult and dangerous, and the test accuracy is poor; and the test method cannot truly simulate the actual use conditions of the hybrid loader with supercapacitors, and cannot truly simulate the charging and discharging performance of the loader driven by supercapacitors and power batteries under actual working conditions, and cannot truly reflect the power performance of the loader. The test process is complicated and cumbersome, and the test equipment requires high accuracy. Summary of the invention

[0005] The present invention overcomes the disadvantages of the above technical problems and provides a method for evaluating the climbing ability of a hybrid power loader with a supercapacitor, which can improve the efficiency of verifying the climbing ability of a hybrid power loader with a supercapacitor and simplify the climbing ability evaluation conditions and measurement costs.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A method for evaluating the climbing ability of a hybrid loader with a supercapacitor, the hybrid loader comprising a power battery, a supercapacitor and a drive motor; the power battery and the supercapacitor are connected in parallel to supply energy to the drive motor, and the power battery, the supercapacitor and the drive motor are controlled by a control system, the method comprising the following steps:

[0008] S1. Charging the power battery and supercapacitor of the hybrid loader to be evaluated, with the voltage and current being constant during the charging process until the power battery and supercapacitor of the hybrid loader are nearly fully charged;

[0009] S2, starting the hybrid loader at the starting point of the straight road and starting to move forward;

[0010] S3, detect the traction force of the hybrid loader when it is moving forward at a constant speed, and determine whether the traction force of the hybrid loader is greater than a. If the traction force is greater than a, execute S4; if the traction force is less than a, execute S5; wherein, the traction force a is determined according to the curb weight of the loader and the maximum load weight of the loader, and the resistance required to climb the slope is approximately converted into the traction force a. The specific calculation formula is: a = 1 / 2 × W × 9.8 N / kg; wherein W represents the sum of the curb weight of the loader and the maximum load weight of the loader, kg;

[0011] S4. Detect whether the power battery of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process. If the maximum output current b is reached, the hybrid loader has a strong climbing ability. If the maximum output current b cannot be reached, the power battery is adjusted through the control system so that the power battery outputs the specified maximum output current as required, and the maximum output power of the power battery is calculated, and the loader's climbing ability meets the requirements;

[0012] S5, detecting whether the power battery of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process, if the output current is b, go to S6; if the maximum output current is not b, adjust the control system of the loader so that the power battery outputs the specified maximum output current as required, and then go to S6;

[0013] S6. Connect the power battery and supercapacitor at the same time, and drive the loader through the supercapacitor and the power battery. The hybrid loader starts to move forward again, and its traction force when moving forward at a constant speed is tested. If the traction force is greater than a at this time, the climbing ability requirement is met, otherwise the climbing ability is insufficient.

[0014] As a preferred solution, in step S1, the power battery and supercapacitor of the hybrid loader are charged to nearly full capacity, that is, the power of the power battery and the supercapacitor are both greater than 95%.

[0015] As a preferred solution, in step S4, the maximum output power of the power battery is calculated by the following formula: max =E 2 / [(Rr) 2 / R+4r], where P max represents the maximum output power of the power battery, E represents the electrical energy of the battery, r represents the internal resistance of the battery, and R is the equivalent resistance of the load.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The hybrid loader with supercapacitor is targeted for dynamic consideration, which can well solve the problem of power output evaluation under complex power output. By simulating the actual use conditions of the hybrid loader with supercapacitor, the charging and discharging performance of the loader driven by supercapacitor and power battery under actual working conditions can be truly simulated, and the power performance of the loader can be truly reflected. The test process is simple. The present invention can provide high-quality samples and data basis for the development of automotive products, so that automotive products have a higher quality level and meet customer needs. It is also beneficial to improve the market competitiveness of products and has important engineering application value.

[0018] 2. By equivalently processing the slope, the resistance required to climb the slope is approximately converted into traction a, which can greatly simplify the inspection cost and inspection conditions, making the inspection more convenient in more areas. By testing the relevant parameters of the loader climbing, and obtaining the traction a equivalently through a specific method, and calculating the maximum output power of the power battery, the comprehensive climbing ability of the loader is obtained, which can effectively evaluate the climbing ability of the loader.

[0019] 3. Taking into account the characteristics of the control system and the power battery management system, specific evaluation indicators are set for the control system and the power battery management system, so that the control system and the power battery management system can be optimized at the same time during the climbing ability test. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of a method for evaluating gradeability of a hybrid power loader with a supercapacitor according to the present invention;

[0021] Figure 2 It is a structural schematic diagram of a hybrid power loader with a supercapacitor according to the present invention.

[0022] The following are marked as follows: 1-engine, 2-generator, 3-power battery, 4-supercapacitor, 5-drive motor, 6-hydraulic motor, 7-travel device, 8-hydraulic device, 9-battery management system, 10-vehicle control system, 11-traction force measurement device DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the specific embodiments of the present invention are only for the purpose of more clearly describing the technical solution and cannot be used as a limitation on the protection scope of the present invention.

[0024] See also Figure 1-Figure 2 , a method for evaluating the gradeability of a hybrid loader with a supercapacitor 4, the hybrid loader comprising a power battery 3, a supercapacitor 4 and a drive motor 5; the power battery 3 and the supercapacitor 4 are connected in parallel to supply energy to the drive motor 5, and the power battery 3, the supercapacitor 4 and the drive motor 5 are controlled by a control system;

[0025] The engine 1 drives the generator 2 to supply energy and charge the power battery 3 and the supercapacitor 4, wherein the power battery 3 and the supercapacitor 4 can also obtain electric energy from the external power grid, and the engine 1 works in its high-efficiency combustion zone; the power battery 3 and the supercapacitor 4 are not connected to each other and are independent of each other and are in a parallel state, and both can supply energy to the drive motor 5 to drive the walking device 7, and can also supply energy to the hydraulic motor 6 to drive the hydraulic device 8; the power battery 3 management system 9 collects and manages parameters such as the power battery 3 temperature, output current, and estimated battery capacity, and the vehicle control system 10 performs system control on the engine 1, the generator 2, the power battery 3, the supercapacitor 4, the drive motor 5, the hydraulic motor 6, etc.;

[0026] First, understand the design performance of the power battery 3 of the hybrid loader used for the test, obtain its specified maximum output current b, and equate the climbing ability to traction. Use the traction of the hybrid loader to approximately evaluate its climbing ability, eliminating the slope requirement. The traction a is determined based on the curb weight of the loader and the maximum load weight of the loader. The resistance to be overcome for climbing is approximately converted into traction a. The specific calculation formula is:

[0027] a=1 / 2×W×9.8N / kg; where W represents the sum of the loader's curb weight and its maximum load weight, kg.

[0028] Before the experiment, prepare reliable and calibrated instruments and equipment as traction measurement devices 11, such as spirit levels, tire pressure gauges, inclinometers, tape measures, comprehensive traction testers, shackles, etc. Check whether the performance parameters of the test loader are normal and whether the lubrication of the rotating and sliding parts is normal. The loader is filled with fuel, hydraulic oil, and equipped with tool accessories and operators in normal operating conditions. Tire pressure, hydraulic oil temperature and pressure, etc. are set within the specified range with reference to this type of loader. The wind speed in the test field is less than 6m / s, and the ambient temperature is around 20 degrees Celsius (plus or minus ten degrees Celsius). The experimental site should be a solid foundation, flat, dry, and clean concrete pavement. The longitudinal slope of the test runway is less than 0.5%, the transverse slope is less than 3%, and the runway length is guaranteed as much as possible, not less than 100m.

[0029] After the preconditions are completed, the following steps are performed to approximately evaluate the climbing performance of the hybrid loader. Specifically, a method for evaluating the climbing performance of a hybrid loader with a supercapacitor 4 includes the following steps:

[0030] S1. Charging the power battery 3 and the supercapacitor 4 of the hybrid loader to be evaluated, and the voltage and current are constant during the charging process until the power battery 3 and the supercapacitor 4 of the hybrid loader are nearly fully charged; in this embodiment, the power battery 3 and the supercapacitor 4 of the hybrid loader are nearly fully charged, that is, the power of the power battery 3 and the supercapacitor 4 are both greater than 95%.

[0031] S2, starting the hybrid loader at the starting point of the straight road and starting to move forward;

[0032] S3, detect the traction force of the hybrid loader when it is moving forward at a constant speed, the speed is greater than 1km / h, and determine whether the traction force of the hybrid loader is greater than a. If the traction force is greater than a, execute S4; if the traction force is less than a, execute S5; wherein, the traction force a is determined according to the curb weight of the loader and the maximum load weight of the loader, and the resistance required to climb the slope is approximately converted into the traction force a, and the specific calculation formula is: a = 1 / 2 × W × 9.8N / kg; wherein W represents the sum of the curb weight of the loader and the maximum load weight of the loader, kg;

[0033] S4. Detect whether the power battery 3 of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process. If the maximum output current b is reached, the hybrid loader has a strong climbing ability. If the maximum output current b cannot be reached, the power battery 3 is adjusted through the control system so that the power battery 3 outputs the specified maximum output current as required, and the maximum output power of the power battery 3 is calculated, and the loader's climbing ability meets the requirements; wherein the maximum output power of the power battery 3 is calculated by the following formula: P max =E 2 / [(Rr) 2 / R+4r], where P max represents the maximum output power of the power battery 3, E represents the electric energy of the battery, r represents the internal resistance of the battery, and R is the equivalent resistance of the load;

[0034] S5, detecting whether the power battery 3 of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process, if the output current is b, go to S6; if the maximum output current is not b, adjust the control system of the loader so that the power battery 3 can output the specified maximum output current as required, and then go to S6;

[0035] S6. Connect the power battery 3 and the supercapacitor 4 at the same time, and drive the loader together through the supercapacitor 4 and the power battery 3. The hybrid loader starts to move forward again, and its traction force when moving forward at a constant speed is tested. The speed is greater than 1 km / h. If the traction force is greater than a at this time, the climbing ability requirement is met, otherwise the climbing ability is insufficient.

[0036] At present, there is no hybrid loader of this type. Combined with the pure electric loaders on the market, the key parameters of the three possible light, medium and heavy hybrid loaders are comprehensively selected and preset (Table 1). According to the evaluation method, simulation calculation and evaluation are carried out on them. The evaluation results are shown in Table 2.

[0037] Table 1 Key parameters for simulation of light, medium and heavy hybrid loaders

[0038]

[0039] Table 2 Simulation evaluation results of light, medium and heavy hybrid loaders

[0040] Loader Type Simulated climbing ability Required climbing ability Gradeability assessment Lightweight 48KN 49KN Failure Medium 270KN 120KN qualified Heavy 310KN 155KN qualified

[0041] The selected light loader was simulated and calculated according to the evaluation method, and the simulated climbing force was 48KN, which was less than the required climbing force of 49KN, and the climbing ability was evaluated as unqualified; the selected medium loader was simulated and calculated according to the evaluation method, and the simulated climbing force was 270KN, which was greater than the required climbing force of 120KN, and the climbing ability was evaluated as qualified; the selected heavy loader was simulated and calculated according to the evaluation method, and the simulated climbing force was 310KN, which was greater than the required climbing force of 155KN, and the climbing ability was evaluated as qualified.

[0042] The present invention can evaluate the climbing ability of a hybrid loader with a supercapacitor and a power battery with a complex energy supply system on flat ground. The proposed climbing approximate evaluation method can be performed on flat ground, which simplifies the climbing ability evaluation conditions and measurement costs, and fills the gap in the climbing ability inspection and evaluation method of a supercapacitor hybrid loader with a complex energy supply system.

[0043] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for evaluating the climbing ability of a hybrid loader with a supercapacitor, the hybrid loader comprising a power battery, a supercapacitor and a drive motor; the power battery and the supercapacitor are connected in parallel to supply energy to the drive motor, and the power battery, the supercapacitor and the drive motor are controlled by a control system; characterized in that: The method comprises the following steps: S1. Charging the power battery and supercapacitor of the hybrid loader to be evaluated, with the voltage and current being constant during the charging process until the power battery and supercapacitor of the hybrid loader are nearly fully charged; S2, starting the hybrid loader at the starting point of the straight road and starting to move forward; S3, detect the traction force of the hybrid loader when it is moving forward at a constant speed, and determine whether the traction force of the hybrid loader is greater than a. If the traction force is greater than a, execute S4; if the traction force is less than a, execute S5; wherein, the traction force a is determined according to the curb weight of the loader and the maximum load weight of the loader, and the resistance required to climb the slope is approximately converted into the traction force a. The specific calculation formula is: a = 1 / 2 × W × 9.8 N / kg; wherein W represents the sum of the curb weight of the loader and the maximum load weight of the loader, kg; S4. Detect whether the power battery of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process. If the maximum output current b is reached, the hybrid loader has a strong climbing ability. If the maximum output current b cannot be reached, the power battery is adjusted through the control system so that the power battery can output the specified maximum output current as required, and the maximum output power of the power battery is calculated, and the loader's climbing ability meets the requirements; S5, detecting whether the power battery of the hybrid loader reaches the specified maximum output current b during the above-mentioned forward process, if the output current is b, go to S6; if the maximum output current is not b, adjust the control system of the loader so that the power battery outputs the specified maximum output current as required, and then go to S6; S6. Connect the power battery and supercapacitor at the same time, and drive the loader through the supercapacitor and the power battery. The hybrid loader starts to move forward again, and its traction force when moving forward at a constant speed is tested. If the traction force is greater than a at this time, the climbing ability requirement is met, otherwise the climbing ability is insufficient.

2. The method for evaluating the gradeability of a hybrid loader with a supercapacitor according to claim 1, characterized in that: In step S1, the power battery and the supercapacitor of the hybrid loader are charged to nearly full capacity, that is, the power of the power battery and the supercapacitor are both greater than 95%.

3. The method for evaluating the gradeability of a hybrid loader with a supercapacitor according to claim 1, characterized in that: In step S4, the maximum output power of the power battery is calculated by the following formula: max =E 2 / [(Rr) 2 / R+4r], where P max Represents the maximum output power of the power battery, E represents the electrical energy of the battery, r represents the internal resistance of the battery, and R is the equivalent resistance of the load.

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