Power distribution method and system for electrified road heavy truck taking pantograph as carrier

Abstract

The invention provides a power distribution method and system for an electrified road heavy truck with a pantograph as a carrier. The method comprises the following steps that the optimal battery electric quantity is obtained when a power battery exerts the maximum charging and discharging power; and real-time rotating speed of the motor, real-time battery power and target torque are obtained in real time. If the real-time battery electric quantity is greater than the optimal battery electric quantity, determining the compensation output power of the vehicle-mounted isolation DCDC by combining the target demand power and the maximum discharge power of the power battery; and the power battery is controlled to enter a discharging state, and the vehicle-mounted isolation DCDC is controlled to compensate the output power to assist in outputting electric energy. If the real-time battery electric quantity is less than or equal to the optimal battery electric quantity, controlling the power battery to enter a charging state; and determining the target output power of the vehicle-mounted isolation DCDC and the target charging power of the power battery in combination with the target demand power and the maximum allowable charging power of the power battery. The method has the effect of improving the energy utilization rate in the operation process of the heavy truck on the electrified road.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle kinetic energy management, and particularly relates to a power distribution method and system for an electrified road heavy truck with a pantograph as a carrier. Background Art

[0002] Currently, pure electric new energy heavy trucks generally adopt a configuration scheme of large-capacity power batteries to meet the vehicle's endurance requirements. However, this results in a relatively large vehicle self-weight, a high price, and the endurance mileage is limited by the battery capacity. Compared with pure electric heavy trucks, the technology of electrified road heavy trucks with pantographs as carriers can reduce the power battery's power demand, reduce the vehicle's self-weight and price, and effectively make up for the deficiency in endurance. This electrified road heavy truck has two power sources: a power battery and an overhead catenary connected through a pantograph. Among them, the electric energy of the catenary is transmitted to the vehicle's high-voltage bus through on-vehicle DCDC inverter rectification.

[0003] For an electrified road heavy truck with a pantograph as a carrier, electric energy travels from the overhead catenary to the pantograph, and after on-vehicle DCDC inverter rectification, it is output to the vehicle's high-voltage bus at a certain power. During the vehicle's operation, the vehicle's power consumption mainly comes from the driving motor's power consumption, and the driving motor's power consumption depends on the driver's power demand and the vehicle's operating mode. In the prior art, the on-vehicle DCDC is usually controlled to output at a fixed power. However, due to the real-time change of the driver's power demand, if the on-vehicle DCDC outputs at a fixed power, it is inevitable to cause an excess or shortage of energy rationing, reducing the energy utilization rate. Moreover, when the vehicle is in the electric braking mode, the battery can obtain electric energy from both the motor and the on-vehicle DCDC simultaneously. If the output power of the DCDC is not controlled, it may cause the problem of overcharging the battery, damaging the battery's life, and also reducing the energy utilization rate. Summary of the Invention

[0004] The present invention provides a power distribution method and system for an electrified road heavy truck with a pantograph as a carrier to solve the problem of low energy utilization rate during the operation of an electrified road heavy truck with a pantograph as a carrier.

[0005] In a first aspect, the present invention provides a power distribution method for an electrified road heavy truck with a pantograph as a carrier, which is applied to a power distribution system of an electrified road heavy truck. The power distribution system includes a pantograph, an on-vehicle isolated DCDC, a vehicle high-voltage bus, a power battery, and a driving motor. The pantograph draws power through an overhead power grid, the pantograph outputs electric energy to the vehicle high-voltage bus through the on-vehicle isolated DCDC, both the power battery and the driving motor are connected to the vehicle high-voltage bus, and the power distribution method includes the following steps:

[0006] Obtain the optimal battery power when the power battery achieves the maximum charge and discharge power;

[0007] Obtain the real-time motor speed of the drive motor and the real-time battery power of the power battery in real time;

[0008] Obtain the target torque in real time through the control pedal of the electric highway heavy truck, and calculate the target demand power by combining the real-time motor speed and the target torque;

[0009] Judge whether the real-time battery power is greater than the optimal battery power;

[0010] If the real-time battery power is greater than the optimal battery power, then determine the compensation output power of the in-vehicle isolated DCDC by combining the target demand power and the maximum discharge power of the power battery, and the compensation output power does not exceed the maximum output power of the in-vehicle isolated DCDC;

[0011] Control the power battery to enter the discharge state, and control the in-vehicle isolated DCDC to assist in outputting electric energy at the compensation output power, and supply power to the drive motor through the vehicle high-voltage bus by combining the power battery and the in-vehicle isolated DCDC;

[0012] If the real-time battery power is less than or equal to the optimal battery power, then control the power battery to enter the charging state;

[0013] Determine the target output power of the in-vehicle isolated DCDC and the target charging power of the power battery by combining the target demand power and the maximum allowable charging power of the power battery, and control the in-vehicle isolated DCDC to output electric energy at the target output power, and supply power to the drive motor and the power battery through the vehicle high-voltage bus, and the target output power does not exceed the maximum output power, and the target output power does not exceed the sum of the target demand power and the maximum allowable charging power.

[0014] Optionally, the determining the compensation output power of the in-vehicle isolated DCDC by combining the target demand power and the maximum discharge power of the power battery includes the following steps:

[0015] Judge whether the real-time battery power is greater than a preset saturated battery power, and the saturated battery power is greater than the optimal battery power;

[0016] If the real-time battery power is greater than the saturated battery power, then set the compensation output power of the in-vehicle isolated DCDC to 0;

[0017] If the real-time battery power is less than or equal to the saturated battery power, then judge whether the target demand power is greater than the maximum discharge power of the power battery;

[0018] If the target required power is greater than the maximum discharge power, determine the compensation output power based on the difference between the target required power and the maximum discharge power, and the compensation output power does not exceed the maximum output power of the on-vehicle isolated DCDC;

[0019] If the target required power is less than or equal to the maximum discharge power, set the compensation output power to 0.

[0020] Optionally, the formula for determining the compensation output power based on the difference between the target required power and the maximum discharge power is as follows:

[0021] Tar 1 P DCDC =(P Driver *(1 + α)-P BatMDsg *β)*γ

[0022] Where: Tar 1 P DCDC ∈[0, P DCDCmax , P DCDCmax represents the maximum output power of the on-vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, Tar 1 P DCDC represents the compensation output power, P Driver represents the target required power, P BatMDag represents the maximum discharge power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, and γ represents the output power adjustment coefficient of the on-vehicle isolated DCDC.

[0023] Optionally, the steps of determining the target output power of the on-vehicle isolated DCDC and the target charging power of the power battery in combination with the target required power and the maximum allowable charging power of the power battery, and controlling the on-vehicle isolated DCDC to output electric energy at the target output power and supply power to the drive motor and the power battery through the vehicle high-voltage bus are as follows:

[0024] Judge whether the real-time battery power is greater than the sub-optimal battery power, and the sub-optimal battery power is less than the optimal battery power;

[0025] If the real-time battery power is greater than the sub-optimal battery power, determine the target charging power of the power battery as the first charging power;

[0026] Determine the target output power of the on-vehicle isolated DCDC as the secondary output power in combination with the target required power and the maximum allowable charging power of the power battery, the secondary output power does not exceed the maximum output power, and the secondary output power does not exceed the sum of the target required power and the maximum allowable charging power;

[0027] Control the in-vehicle isolated DCDC to output electric energy at the secondary output power, supply power to the drive motor through the vehicle high-voltage bus, and charge the power battery at the first charging power;

[0028] If the real-time battery power is less than or equal to the sub-optimal battery power, determine that the target charging power of the power battery is the second charging power, and the second charging power is greater than the first charging power;

[0029] Combine the target demand power and the maximum allowable charging power to determine that the target output power of the in-vehicle isolated DCDC is the primary output power. The primary output power does not exceed the maximum output power, and the primary output power does not exceed the sum of the target demand power and the maximum allowable charging power;

[0030] Control the in-vehicle isolated DCDC to output electric energy at the primary output power, supply power to the drive motor through the vehicle high-voltage bus, and charge the power battery at the second charging power.

[0031] Optionally, the drive motor converts electric energy into mechanical energy in the drive mode, and converts mechanical energy into electric energy in the braking mode;

[0032] The step of combining the target demand power and the maximum allowable charging power of the power battery to determine that the target output power of the in-vehicle isolated DCDC is the secondary output power includes the following steps:

[0033] Judge the operation mode of the electric highway heavy truck through a preset mode determination power range. The operation mode includes a drive mode, a braking mode, and a state holding mode;

[0034] If in the drive mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the secondary output power according to the target demand power and the maximum allowable charging power of the power battery is as follows:

[0035] Tar 2 P DCDC =(P Driver *(1 + α)+P BatMCChrg *β*λ′)*γ

[0036] In the formula: Tar 2 P DCDC ∈[0, P DCDCmax , P DCDCmax represents the maximum output power of the in-vehicle isolated DCDC, α>0, 0<β<1, γ>1, 0<λ′<0.5, Tar 2 PDCDC Indicates the secondary output power, P Driver Indicates the target demand power, P BatMCChrg Indicates the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the in-vehicle isolated DCDC, and λ′ represents the charging adjustment coefficient of the secondary output power;

[0037] If in the braking mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the secondary output power according to the target demand power and the maximum allowable charging power of the power battery is as follows:

[0038] Tar 2 P DCDC =(P Driver *(1 - α)+P BatMCChrg *β*λ′)*γ

[0039] If in the state holding mode, the output power of the in-vehicle isolated DCDC at the previous moment is used as the target output power.

[0040] Optionally, the drive motor converts electrical energy into mechanical energy in the drive mode, and the drive motor converts mechanical energy into electrical energy in the braking mode;

[0041] Determining the target output power of the in-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power includes the following steps:

[0042] Judge the operating mode of the electric highway heavy truck through a preset mode determination power range, and the operating mode includes a drive mode, a braking mode, and a state holding mode;

[0043] If in the drive mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows:

[0044] Tar 3 P DCDC =(P Driver *(1 + α)+P BatMCChrg *β*λ)*γ

[0045] In the formula: Tar 3 P DCDC ∈[0, P DCDCmax , P DCDCmax Represents the maximum output power of the in-vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, 0.5 < λ < 1, Tar 3 P DCDCIndicates the primary output power, P Driver Indicates the target demand power, P BatMCChrg Indicates the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the on-vehicle isolated DCDC, and λ represents the charging adjustment coefficient of the primary output power;

[0046] If in the braking mode, the formula for determining the target output power of the on-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows:

[0047] Tar 3 P DCDC =(P Driver *(1 - α)+P BatMCChrg *β*λ)*γ

[0048] If in the state holding mode, use the output power of the on-vehicle isolated DCDC at the previous moment as the target output power.

[0049] Optionally, the method for judging the operation mode of the electric highway heavy truck by a preset mode judgment power range includes the following steps:

[0050] Judge whether the target demand power is greater than or equal to the maximum value of the preset mode judgment power range;

[0051] If the target demand power is greater than or equal to the maximum value, determine that the operation mode of the electric highway heavy truck is in the driving mode;

[0052] If the target demand power is less than the maximum value, judge whether the target demand power is less than or equal to the minimum value of the mode judgment power range;

[0053] If the target demand power is greater than the minimum value, determine that the operation mode is in the state holding mode;

[0054] If the target demand power is less than or equal to the minimum value, determine that the operation mode is in the braking mode.

[0055] Optionally, the method further includes the following steps:

[0056] Obtain the radiator temperature of the on-vehicle isolated DCDC in real time;

[0057] Judge whether the radiator temperature exceeds the preset temperature threshold;

[0058] If the radiator temperature exceeds the temperature threshold, linearly reduce the maximum output power according to the radiator temperature.

[0059] Optionally, the method further includes the following steps:

[0060] Obtain the input voltage of the on-vehicle isolated DCDC in real time;

[0061] Determine whether the input voltage is lower than a preset voltage threshold;

[0062] If the input voltage is lower than the voltage threshold, linearly reduce the maximum output power according to the input voltage.

[0063] In a second aspect, the present invention further provides a power distribution system for an electrified road heavy truck with a pantograph as a carrier, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the power distribution method for the electrified road heavy truck with a pantograph as a carrier as described in the first aspect.

[0064] The beneficial effects of the present invention are:

[0065] The present invention intends to propose a power distribution method applicable to an electrified road heavy truck with a pantograph as a carrier. From the perspective of vehicle control, this method adjusts the output power of the on-vehicle isolated DCDC in stages based on the battery power level, determines the output power of the on-vehicle DCDC according to the driver's target demand power, battery power state, and battery charge and discharge power, comprehensively considers the efficiency factor and the endurance requirement after the vehicle disengages from the pantograph, thereby realizing the reasonable allocation of catenary and battery energy, and further improving the energy utilization rate during vehicle operation. Description of the Drawings

[0066] Figure 1 It is a schematic diagram of the electric energy transmission structure of the power distribution system in the present invention.

[0067] Figure 2 It is a schematic flowchart of the power distribution method for an electrified road heavy truck with a pantograph as a carrier in the present invention.

[0068] Figure 3 It is a schematic diagram of the phased charge and discharge scheme in the present invention.

[0069] Figure 4 It is a broken line diagram for adjusting the maximum output power according to the radiator temperature in the present invention.

[0070] Figure 5 It is a broken line diagram for adjusting the maximum output power according to the input voltage in the present invention. Detailed Embodiments

[0071] The terms "first", "second", etc. in the description and claims of the present invention are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0072] The present invention discloses a power distribution method for an electrified road heavy truck with a pantograph as a carrier. It is applied to a power distribution system for an electrified road heavy truck with a pantograph as a carrier. Referring to Figure 1 , the power distribution system includes a pantograph, an in-vehicle isolated DCDC, a vehicle high-voltage bus, a power battery, and a drive motor. The pantograph draws power from an overhead power grid, and the pantograph outputs electrical energy to the vehicle high-voltage bus through the in-vehicle isolated DCDC. Both the power battery and the drive motor are connected to the vehicle high-voltage bus, and other electrical devices of the electrified road heavy truck are also connected to the vehicle high-voltage bus. The power battery and the overhead line network serve as power sources to supply power to the drive motor and other electrical devices on the vehicle high-voltage bus. The in-vehicle isolated DCDC in this system has an anti-backflow function, and the output side is designed with a unidirectional output function to prevent current from flowing back to the in-vehicle isolated DCDC in the braking power generation mode; in the braking mode, the drive motor converts mechanical energy into electrical energy and feeds it back to the bus. Electrical energy flows from the overhead catenary to the pantograph, undergoes inversion and rectification by the in-vehicle isolated DCDC, and is output to the vehicle high-voltage bus at a certain power. By adjusting the output power of the in-vehicle isolated DCDC, the allocation of energy can be completed.

[0073] Referring to Figure 2 , the power distribution method for an electrified road heavy truck with a pantograph as a carrier specifically includes the following steps:

[0074] S101. Obtain the optimal battery charge when the power battery exerts the maximum charge and discharge power.

[0075] Among them, the influence of the battery charge of an electric vehicle on the maximum charge and discharge power is not a fixed value, but a range. Generally speaking, the charge and discharge power of the battery is closely related to its remaining charge (SOC, State of Charge). Generally, when the SOC is at an intermediate level, that is, about 40%-60%, the charge and discharge power of the battery can usually reach the maximum. This is because when the battery charge is too low or too high, due to the limitations of chemical reactions, the charge and discharge efficiency of the battery will decrease, resulting in a reduction in the charge and discharge power.

[0076] The optimal battery power is the power value when the power battery can exert the maximum charge and discharge power and meet the endurance requirement, and this power value is determined through experiments and model simulations. In the experiment, the charge and discharge power of the battery can be measured by changing the battery power and measuring its charge and discharge power at different powers, so as to obtain the relationship between the maximum charge and discharge power of the battery and the power. At the same time, a mathematical model of the battery can also be established, and the charge and discharge power of the battery at different powers can be predicted through simulation calculations. Combining these two methods can more accurately determine the relationship between the maximum charge and discharge power of the battery and the power. In this embodiment, the battery power that can exert the maximum charge and discharge power is determined to be 40% - 85%. Considering the endurance requirement of the electrified road heavy truck, in this embodiment, the optimal battery power can be set to 80%.

[0077] S102. Obtain the real-time motor speed of the drive motor and the real-time battery power of the power battery in real time.

[0078] Among them, the real-time motor speed of the drive motor and the actual battery power of the power battery can be obtained through preset sensors.

[0079] S103. Obtain the target torque in real time through the control pedal of the electrified road heavy truck, and calculate the target demand power by combining the real-time motor speed and the target torque.

[0080] Among them, the target demand power can be understood as the driver's demand power, and the target demand power P Driver is the mechanical power of the motor, and is calculated according to the real-time motor speed n cur and the target torque T tar The target torque T tar has a sign. The control pedal includes an accelerator pedal and a brake pedal. When the driver steps on the accelerator pedal, it means motor drive, and at this time T tar >0; when the driver steps on the brake pedal, it means motor braking, and at this time T tar <0.

[0081] The target demand power P Driver is the product of the acting force F and the speed V: P Driver =F·V;

[0082] The target torque T tar is the product of the acting force F and the acting radius R: T tar =F·R;

[0083] The linear speed is the product of the circumference and the speed: V = 2πR·n cur / 60;

[0084] Combining the above formulas, the calculation formula of the target demand power P Driver can be obtained, and the specific formula is as follows:

[0085] P Driver = T tar · π · n cur / 30 ≈ T tar · n cur / 9.549。

[0086] S104. Determine whether the real-time battery power is greater than the optimal battery power. If the real-time battery power is greater than the optimal battery power, then execute step S105; if the real-time battery power is less than or equal to the optimal battery power, then execute step S107.

[0087] S105. Determine the compensated output power of the on-vehicle isolated DCDC in combination with the target demand power and the maximum discharge power of the power battery.

[0088] Among them, the compensated output power does not exceed the maximum output power of the on-vehicle isolated DCDC.

[0089] S106. Control the power battery to enter the discharge state, and control the on-vehicle isolated DCDC to assist in outputting electric energy with the compensated output power, and supply power to the drive motor through the vehicle high-voltage bus in combination with the power battery and the on-vehicle isolated DCDC.

[0090] S107. Control the power battery to enter the charging state.

[0091] S108. Determine the target output power of the on-vehicle isolated DCDC and the target charging power of the power battery in combination with the target demand power and the maximum allowable charging power of the power battery, and control the on-vehicle isolated DCDC to output electric energy with the target output power, and supply power to the drive motor and the power battery through the vehicle high-voltage bus.

[0092] Among them, the maximum allowable charging power is the maximum charging power that the power battery is allowed to maintain in a continuous charging state. The target output power does not exceed the maximum output power, and the target output power does not exceed the sum of the target demand power and the maximum allowable charging power.

[0093] The implementation principle of this embodiment is:

[0094] To meet the power demand of the vehicle after the pantograph is detached, the battery charge is maintained at a relatively high level before the pantograph is detached. When the battery charge is at the optimal battery charge level, the maximum charge and discharge power can be exerted. Therefore, the optimal battery charge level is used as the battery charge maintenance point. If the real-time battery charge is greater than the optimal battery charge level, the compensated output power of the on-vehicle isolated DCDC is determined by combining the target demand power and the maximum discharge power of the power battery, the power battery is controlled to enter the discharge state, and the on-vehicle isolated DCDC is controlled to assist in outputting electric energy with the compensated output power; if the real-time battery charge is less than or equal to the optimal battery charge level, the power battery is controlled to enter the charging state, and the target output power of the on-vehicle isolated DCDC and the target charging power of the power battery are determined by combining the target demand power and the maximum allowable charging power of the power battery; it should be noted that in the braking mode, the sum of the DCDC output power and the drive motor braking feedback power cannot exceed the maximum charging power of the battery; this enables the battery charge to be stabilized near the optimal battery charge level.

[0095] Therefore, from the perspective of vehicle control, this embodiment adjusts the output power of the on-vehicle isolated DCDC in stages based on the level of the battery charge, determines the output power of the on-vehicle DCDC according to the driver's target demand power, the battery charge state, and the battery charge and discharge power, comprehensively considers the efficiency factor and the endurance requirement after the vehicle's pantograph is detached, thereby realizing the reasonable allocation of the line network and battery energy, and further improving the energy utilization rate during vehicle operation.

[0096] In one of the embodiments, step S105 specifically includes the following steps:

[0097] Judge whether the real-time battery charge is greater than the preset saturated battery charge, and the saturated battery charge is greater than the optimal battery charge;

[0098] If the real-time battery charge is greater than the saturated battery charge, set the compensated output power of the on-vehicle isolated DCDC to 0;

[0099] If the real-time battery charge is less than or equal to the saturated battery charge, judge whether the target demand power is greater than the maximum discharge power of the power battery;

[0100] If the target demand power is greater than the maximum discharge power, determine the compensated output power based on the difference between the target demand power and the maximum discharge power, and the compensated output power does not exceed the maximum output power of the on-vehicle isolated DCDC;

[0101] If the target demand power is less than or equal to the maximum discharge power, set the compensated output power to 0.

[0102] In this embodiment, the formula for determining the compensated output power based on the difference between the target demand power and the maximum discharge power is as follows:

[0103] Tar 1 PDCDC = (P Driver * (1 + α) - P BatMDsg * β) * γ

[0104] Where: Tar 1 P DCDC ∈ [0, P DCDCmax , P DCDCmax represents the maximum output power of the in - vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, Tar 1 P DCDC represents the compensated output power, P Driver represents the target demand power, P BatMDsg represents the maximum discharge power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, and γ represents the output power adjustment coefficient of the in - vehicle isolated DCDC. In the driving mode, considering the efficiency factor of the driving motor converting electrical energy into mechanical energy, the mode adjustment coefficient is set for adjustment. The mode adjustment coefficient α can be set to 0.05, that is, the electrical power at the input end of the driving motor is about 1.05 times the mechanical power at the output end. On the other hand, to prevent the power battery from discharging at the maximum power for a long time and extend the service life of the power battery, the battery protection adjustment coefficient is set to adjust the maximum discharge power. The battery protection adjustment coefficient β is usually set to 0.8. Also considering the energy conversion efficiency of the in - vehicle isolated DCDC, the output power adjustment coefficient is set to amplify and adjust the finally calculated output power. The output power adjustment coefficient γ is usually set to 1.05.

[0105] Referring to Figure 3 , Figure 3 reflects a specific example of the staged control of the output power of the in - vehicle isolated DCDC in this embodiment. In Figure 3 , assuming that the optimal battery charge is 80% and the saturated battery charge is 95%. When the real - time battery charge is 80%, the maximum charge - discharge power can be exerted. Therefore, the real - time battery charge of 80% is used as the battery charge maintenance point. When the real - time battery charge is higher than 80%, the compensated output power of the in - vehicle isolated DCDC is determined by combining the target demand power and the maximum discharge power of the power battery, the power battery is controlled to enter the discharge state, and the in - vehicle isolated DCDC is controlled to assist in outputting electrical energy with the compensated output power; when the real - time battery charge is lower than 80%, the power battery is controlled to enter the charging state, and the target output power of the in - vehicle isolated DCDC and the target charging power of the power battery are determined by combining the target demand power and the maximum allowable charging power of the power battery; it should be noted that in the braking mode, the sum of the output power of the in - vehicle isolated DCDC and the braking feedback power of the driving motor cannot exceed the maximum charging power of the battery, so that the battery charge is stabilized near 80%.

[0106] If the target demand power is less than the maximum discharge power, i.e., PDriver *(1 + α) - P BatMDsg *When β < 0, the output power of the on - vehicle isolated DCDC is 0. At this time, the power demand is met only by the power battery discharging. When 80% < real - time battery power < 95%, the power battery discharges preferentially. Note that when the target demand power is greater than the maximum discharge power of the power battery, the on - vehicle isolated DCDC should perform power compensation; when the real - time battery power ≥ 95%, to prevent over - charging of the battery, the DCDC output power is 0 at this stage.

[0107] In one implementation, step S108 specifically includes the following steps:

[0108] Judge whether the real - time battery power is greater than the sub - optimal battery power, and the sub - optimal battery power is less than the optimal battery power;

[0109] If the real - time battery power is greater than the sub - optimal battery power, determine the target charging power of the power battery as the first charging power;

[0110] Combine the target demand power and the maximum allowable charging power of the power battery to determine the target output power of the on - vehicle isolated DCDC as the secondary output power. The secondary output power does not exceed the maximum output power, and the secondary output power does not exceed the sum of the target demand power and the maximum allowable charging power;

[0111] Control the on - vehicle isolated DCDC to output electric energy at the secondary output power, supply power to the drive motor through the vehicle high - voltage bus, and charge the power battery at the first charging power;

[0112] If the real - time battery power is less than or equal to the sub - optimal battery power, determine the target charging power of the power battery as the second charging power, and the second charging power is greater than the first charging power;

[0113] Combine the target demand power and the maximum allowable charging power to determine the target output power of the on - vehicle isolated DCDC as the primary output power. The primary output power does not exceed the maximum output power, and the primary output power does not exceed the sum of the target demand power and the maximum allowable charging power;

[0114] Control the on - vehicle isolated DCDC to output electric energy at the primary output power, supply power to the drive motor through the vehicle high - voltage bus, and charge the power battery at the second charging power.

[0115] In this embodiment, to meet the power demand of the vehicle after pantograph disconnection, before pantograph disconnection, the battery power is maintained at a relatively high level. When the battery power is the optimal battery power, the maximum charge and discharge power can be exerted. Therefore, the optimal battery power is used as the battery power maintenance point. When the battery power is higher than the optimal battery power, the battery discharges preferentially; when the battery power is lower than the optimal battery power but higher than the sub-optimal battery power, while the in-vehicle isolated DCDC supplies power to the drive motor, it charges the battery with a small power; when the battery power is lower than the sub-optimal battery power, while supplying power to the drive motor, it charges the battery with a large power; in this way, the battery power is stabilized near the optimal battery power. It should be noted that in the braking mode, the sum of the DCDC output power and the drive motor braking feedback power cannot exceed the maximum allowable continuous charging power of the battery.

[0116] In this embodiment, the drive motor converts electrical energy into mechanical energy in the drive mode, and converts mechanical energy into electrical energy in the braking mode. The step of determining the target output power of the in-vehicle isolated DCDC as the secondary output power in combination with the target demand power and the maximum allowable charging power of the power battery specifically includes the following steps:

[0117] Judge the operation mode of the electric highway heavy truck through a preset mode determination power range. The operation modes include drive mode, braking mode and state holding mode;

[0118] If it is in the drive mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the secondary output power according to the target demand power and the maximum allowable charging power of the power battery is as follows:

[0119] Tar 2 P DCDC =(P Driver *(1 + α)+P BatMCChrg *β*λ′)*γ

[0120] In the formula: Tar 2 P DCDC ∈[0, P DCDCmax , P DCDCmax represents the maximum output power of the in-vehicle isolated DCDC, α>0, 0<β<1, γ>1, 0<λ′<0.5, Tar 2 P DCDC represents the secondary output power, P Driver represents the target demand power, P BatMCChrg represents the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the in-vehicle isolated DCDC, and λ′ represents the charging adjustment coefficient of the secondary output power;

[0121] If in the braking mode, the formula for determining the target output power of the on-vehicle isolated DCDC as the secondary output power based on the target demand power and the maximum allowable charging power of the power battery is as follows:

[0122] Tar 2 P DCDC =(P Driver *(1 - α)+P BatMCChrg *β*λ′)*γ

[0123] If in the state - holding mode, the output power of the on-vehicle isolated DCDC at the previous moment is used as the target output power.

[0124] In this embodiment, since the drive motor converts electrical energy into mechanical energy in the driving mode and converts mechanical energy into electrical energy in the braking mode, by setting the mode adjustment coefficient, the coefficient of the target demand power can be adjusted, thereby taking into account the energy conversion efficiency, improving the accuracy of the finally calculated output power, and further improving the energy utilization rate.

[0125] In one of the embodiments, the drive motor converts electrical energy into mechanical energy in the driving mode and converts mechanical energy into electrical energy in the braking mode. The step of determining the target output power of the on-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power includes the following steps:

[0126] Judge the operating mode of the electric highway heavy truck through a preset mode - determination power interval. The operating modes include the driving mode, the braking mode, and the state - holding mode;

[0127] If in the driving mode, the formula for determining the target output power of the on-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows:

[0128] Tar 3 P DCDC =(P Driver *(1 + α)+P BatMCChrg *β*λ)*γ

[0129] Where: Tar 3 P DCDC ∈[0, P DCDCmax , P DCDCmax represents the maximum output power of the on-vehicle isolated DCDC, α>0, 0<β<1, γ>1, 0.5<λ<1, Tar a P DCDC represents the primary output power, P Driver represents the target demand power, P BatMCChrgIndicates the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the on-vehicle isolation DCDC, and λ represents the charging adjustment coefficient of the primary output power;

[0130] If in the braking mode, the formula for determining the target output power of the on-vehicle isolation DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows:

[0131] Tar a P DCDC =(P Driver *(1 - α)+P BatMCChrg *β*λ)*γ

[0132] If in the state holding mode, the output power of the on-vehicle isolation DCDC at the previous moment is used as the target output power.

[0133] In this embodiment, since the drive motor converts electrical energy into mechanical energy in the drive mode and converts mechanical energy into electrical energy in the braking mode, by setting the mode adjustment coefficient, the coefficient of the target demand power can be adjusted, thereby taking into account the energy conversion efficiency, improving the accuracy of the finally calculated output power, and further improving the energy utilization rate.

[0134] In one of the embodiments, the step of determining the operating mode of the electric highway heavy truck by presetting the mode determination power interval specifically includes the following steps:

[0135] Judge whether the target demand power is greater than or equal to the interval maximum value of the preset mode determination power interval;

[0136] If the target demand power is greater than or equal to the interval maximum value, it is determined that the operating mode of the electric highway heavy truck is in the drive mode;

[0137] If the target demand power is less than the interval maximum value, judge whether the target demand power is less than or equal to the interval minimum value of the mode determination power interval;

[0138] If the target demand power is greater than the interval minimum value, it is determined that the operating mode is in the state holding mode;

[0139] If the target demand power is less than or equal to the interval minimum value, it is determined that the operating mode is in the braking mode.

[0140] In this embodiment, assume that the interval maximum value of the preset mode determination power interval is P acc , and the interval minimum value is P brake , so that P accIt is determined as the drive mode determination power, and the specific value can be adjusted according to the actual situation. It is temporarily set to -1 Kw in the implementation manner. When the target demand power P Driver ≥P acc , it can be considered as the drive mode. Let P brake be determined as the braking mode determination power, and the specific value can be adjusted according to the actual situation. In this implementation manner, it is temporarily set to -5 Kw. When the target demand power P Driver ≤P acc , it can be considered as the braking mode. When P brake <P Driver <P acc , it can be considered as the state holding mode.

[0141] In one of the implementation manners, the method further includes the following steps:

[0142] Obtain the radiator temperature of the in-vehicle isolated DCDC in real time;

[0143] Determine whether the radiator temperature exceeds the preset temperature threshold;

[0144] If the radiator temperature exceeds the temperature threshold, linearly reduce the maximum output power according to the radiator temperature.

[0145] In this implementation manner, based on the output characteristics of the in-vehicle isolated DCDC, it is necessary to limit the maximum output power according to its radiator temperature to ensure its safe operation. Refer to Figure 4 , Figure 4 shows a specific embodiment in this implementation manner. Assuming that the temperature threshold is 75 °C, when the radiator temperature exceeds 75 °C, as the radiator temperature gradually rises to 85 °C, the maximum output power linearly decreases from the original 250 kW to 50 kW.

[0146] In one of the implementation manners, the method further includes the following steps:

[0147] Obtain the input voltage of the in-vehicle isolated DCDC in real time;

[0148] Determine whether the input voltage is lower than the preset voltage threshold;

[0149] If the input voltage is lower than the voltage threshold, linearly reduce the maximum output power according to the input voltage.

[0150] In this implementation manner, based on the output characteristics of the in-vehicle isolated DCDC, it is necessary to limit the maximum output power according to the magnitude of its input voltage to ensure its safe operation. Refer to Figure 5 , Figure 5An exemplary embodiment of the present implementation is shown. Assuming that the voltage threshold is 1350V, when the input voltage is lower than 1350V, as the input voltage gradually decreases to 1200V, the maximum output power linearly decreases from the original 250kW to 200kW.

[0151] The present invention also discloses a power distribution system for an electrified road heavy truck with a pantograph as a carrier, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the power distribution method for the electrified road heavy truck with a pantograph as a carrier described in any of the above embodiments.

[0152] Those of ordinary skill in the art should understand that the discussion of any above embodiment is only exemplary and is not intended to imply that the protection scope of the present application is limited to these examples. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments in the present application as above. For the sake of brevity, they are not provided in detail.

[0153] One or more embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the present application. Therefore, any omission, modification, equivalent substitution, improvement, etc. made within the spirit and principle of one or more embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A power distribution method for an electrified road heavy truck with a pantograph as the carrier, which is applied to the power distribution system of the electrified road heavy truck. The power distribution system includes a pantograph, an in-vehicle isolated DCDC, a vehicle high-voltage bus, a power battery, and a drive motor. The pantograph draws power from an overhead power grid, and the pantograph outputs electrical energy to the vehicle high-voltage bus through the in-vehicle isolated DCDC. Both the power battery and the drive motor are connected to the vehicle high-voltage bus. Characterized in that, The power distribution method includes the following steps: Obtain the optimal battery charge when the power battery exerts the maximum charge and discharge power; Obtain the real-time motor speed of the drive motor and the real-time battery charge of the power battery in real time; Obtain the target torque in real time through the control pedal of the electrified road heavy truck, and calculate the target demand power by combining the real-time motor speed and the target torque; Judge whether the real-time battery charge is greater than the optimal battery charge; If the real-time battery charge is greater than the optimal battery charge, then determine the compensation output power of the in-vehicle isolated DCDC by combining the target demand power and the maximum discharge power of the power battery, and the compensation output power does not exceed the maximum output power of the in-vehicle isolated DCDC; Control the power battery to enter the discharge state, and control the in-vehicle isolated DCDC to assist in outputting electrical energy at the compensation output power. Combine the power battery and the in-vehicle isolated DCDC to supply power to the drive motor through the vehicle high-voltage bus; If the real-time battery charge is less than or equal to the optimal battery charge, then control the power battery to enter the charging state; Determine the target output power of the in-vehicle isolated DCDC and the target charging power of the power battery by combining the target demand power and the maximum allowable charging power of the power battery, and control the in-vehicle isolated DCDC to output electrical energy at the target output power, and supply power to the drive motor and the power battery through the vehicle high-voltage bus. The target output power does not exceed the maximum output power, and the target output power does not exceed the sum of the target demand power and the maximum allowable charging power.

2. The power distribution method for an electrified road heavy truck with a pantograph as the carrier according to claim 1, Characterized in that, The step of determining the compensation output power of the in-vehicle isolated DCDC by combining the target demand power and the maximum discharge power of the power battery includes the following steps: Judge whether the real-time battery charge is greater than a preset saturated battery charge, and the saturated battery charge is greater than the optimal battery charge; If the real-time battery charge is greater than the saturated battery charge, then set the compensation output power of the in-vehicle isolated DCDC to 0; If the real-time battery charge is less than or equal to the saturated battery charge, then judge whether the target demand power is greater than the maximum discharge power of the power battery; If the target required power is greater than the maximum discharge power, determine the compensation output power based on the difference between the target required power and the maximum discharge power, and the compensation output power does not exceed the maximum output power of the on-vehicle isolated DCDC; If the target required power is less than or equal to the maximum discharge power, set the compensation output power to 0.

3. The power distribution method of the electrified road heavy truck with a pantograph as the carrier according to claim 2, characterized in that, The formula for determining the compensation output power based on the difference between the target required power and the maximum discharge power is as follows: Tar 1 P DCDC = (P Driver * (1 + α) - P BatMDsg * β) * γ Where: Tar 1 P DCDC ∈ [0, P DCDCmax , P DCDCmax represents the maximum output power of the in-vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, Tar 1 P DCDC represents the compensated output power, P Driver represents the target demand power, P BatMDsg represents the maximum discharge power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, and γ represents the output power adjustment coefficient of the in-vehicle isolated DCDC.

4. The power distribution method of the electrified road heavy truck with a pantograph as the carrier according to claim 1, characterized in that, Combining the target required power and the maximum allowable charging power of the power battery to determine the target output power of the on-vehicle isolated DCDC and the target charging power of the power battery, and controlling the on-vehicle isolated DCDC to output electric energy at the target output power, and supplying power to the drive motor and the power battery through the vehicle high-voltage bus includes the following steps: Judge whether the real-time battery power is greater than the sub-optimal battery power, and the sub-optimal battery power is less than the optimal battery power; If the real-time battery power is greater than the sub-optimal battery power, determine the target charging power of the power battery as the first charging power; Combining the target required power and the maximum allowable charging power of the power battery to determine the target output power of the on-vehicle isolated DCDC as the secondary output power, the secondary output power does not exceed the maximum output power, and the secondary output power does not exceed the sum of the target required power and the maximum allowable charging power; Control the on-vehicle isolated DCDC to output electric energy at the secondary output power, supply power to the drive motor through the vehicle high-voltage bus, and charge the power battery at the first charging power; If the real-time battery power is less than or equal to the sub-optimal battery power, determine the target charging power of the power battery as the second charging power, and the second charging power is greater than the first charging power; Combining the target required power and the maximum allowable charging power to determine the target output power of the on-vehicle isolated DCDC as the primary output power, the primary output power does not exceed the maximum output power, and the primary output power does not exceed the sum of the target required power and the maximum allowable charging power; Control the on-vehicle isolated DCDC to output electric energy at the primary output power, supply power to the drive motor through the vehicle high-voltage bus, and charge the power battery at the second charging power.

5. The power distribution method of the electrified road heavy truck with a pantograph as the carrier according to claim 4, characterized in that, The drive motor converts electrical energy into mechanical energy in the drive mode, and converts mechanical energy into electrical energy in the braking mode; The steps of combining the target required power and the maximum allowable charging power of the power battery to determine the target output power of the on-vehicle isolated DCDC as the secondary output power include the following: Judge the operation mode of the electrified road heavy truck by preset mode determination power intervals, and the operation modes include a driving mode, a braking mode, and a state holding mode; If in the driving mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the secondary output power according to the target demand power and the maximum allowable charging power of the power battery is as follows: Tar 2 P DCDC = (P Driver * (1 + α) + P BatMCChrg * β * λ′) * γ Where: Tar 2 P DCDC ∈ [0, P DCDCmax , P DCDCmax represents the maximum output power of the on-vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, 0 < λ′ < 0.5, Tar 2 P DCDC represents the secondary output power, P Driver represents the target demand power, P BatMCChrg represents the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the on-vehicle isolated DCDC, and λ′ represents the charging adjustment coefficient of the secondary output power; If in the braking mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the secondary output power according to the target demand power and the maximum allowable charging power of the power battery is as follows: Tar 2 P DCDC = (P Driver * (1 - α) + P BatMCChrg * β * λ') * γ If in the state holding mode, use the output power of the in-vehicle isolated DCDC at the previous moment as the target output power.

6. The power distribution method of the electrified road heavy truck with a pantograph as a carrier according to claim 4, characterized in that, The drive motor converts electrical energy into mechanical energy in the driving mode, and the drive motor converts mechanical energy into electrical energy in the braking mode; The determination of the target output power of the in-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power includes the following steps: Judge the operation mode of the electrified road heavy truck by preset mode determination power intervals, and the operation modes include a driving mode, a braking mode, and a state holding mode; If in the driving mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows: Tar 3 P DCDC = (P Driver * (1 + α) + P BatMCChrg * β * λ) * γ where: Tar 3 P DCDC ∈ [0, P DCDCmax , P DCDCmax represents the maximum output power of the on-vehicle isolated DCDC, α > 0, 0 < β < 1, γ > 1, 0.5 < λ < 1, Tar 3 P DCDC represents the primary output power, P Driver represents the target demand power, P BatMCChrg represents the maximum allowable charging power, α represents the mode adjustment coefficient, β represents the battery protection adjustment coefficient, γ represents the output power adjustment coefficient of the on-vehicle isolated DCDC, and λ represents the charging adjustment coefficient of the primary output power; If in the braking mode, the formula for determining the target output power of the in-vehicle isolated DCDC as the primary output power by combining the target demand power and the maximum allowable charging power is as follows: Tar 3 P DCDC = (P Driver * (1 - α) + P BatMCChrg * β * λ) * γ If in the state holding mode, use the output power of the in-vehicle isolated DCDC at the previous moment as the target output power.

7. The power distribution method of the electrified road heavy truck with a pantograph as a carrier according to claim 5 or 6, characterized in that, The judgment of the operation mode of the electrified road heavy truck by preset mode determination power intervals includes the following steps: Judge whether the target demand power is greater than or equal to the interval maximum value of the preset mode determination power interval; If the target demand power is greater than or equal to the interval maximum value, it is determined that the operation mode of the electrified road heavy truck is in the driving mode; If the target demand power is less than the interval maximum value, judge whether the target demand power is less than or equal to the interval minimum value of the mode determination power interval; If the target demand power is greater than the interval minimum value, it is determined that the operation mode is in the state holding mode; If the target demand power is less than or equal to the interval minimum value, it is determined that the operation mode is in the braking mode.

8. The power distribution method of the electrified road heavy truck with a pantograph as a carrier according to claim 1, characterized in that, The method further includes the following steps: Obtain the radiator temperature of the in-vehicle isolated DCDC in real time; Judge whether the radiator temperature exceeds a preset temperature threshold; If the temperature of the radiator exceeds the temperature threshold, the maximum output power is linearly reduced according to the radiator temperature.

9. The power distribution method of the electrified road heavy truck with a pantograph as the carrier according to claim 1, characterized in that, the method further comprises the following steps: Obtain the input voltage of the in-vehicle isolated DCDC in real time; Judge whether the input voltage is lower than a preset voltage threshold; If the input voltage is lower than the voltage threshold, the maximum output power is linearly reduced according to the input voltage.

10. A power distribution system of an electrified road heavy truck with a pantograph as the carrier, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements the power distribution method of the electrified road heavy truck with a pantograph as the carrier according to any one of claims 1 to 9.

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