An optimized energy distribution method, system, and electric vehicle for electric vehicles.

Abstract

An optimized energy distribution method, system, and electric vehicle for electric vehicles, based on the battery supplying power or recovering energy for the front-wheel drive and / or rear-wheel drive, includes a first supercapacitor and a second supercapacitor. The first supercapacitor supplies power or recovers energy for the rear-wheel drive, and the second supercapacitor supplies power or recovers energy for the front-wheel drive. The specific method includes: 1) determining whether the remaining charge of the first and second supercapacitors exceeds a preset threshold; if so, proceeding to 2); 2) acquiring a road topographic map ahead using an electronic horizon system to predict whether there is a continuous slope ahead; if so, proceeding to 3); 3) predicting the braking force distribution ratio during braking based on the continuous slope value ahead, and pre-allocating the current power output of the first and second supercapacitors according to this braking distribution ratio, returning to step 1). This invention expands the total capacity of the supercapacitors and improves the recovery of braking or coasting energy.

Description

Technical Field

[0001] This invention relates to the field of electric vehicles, and in particular to an optimized energy distribution method, system, and electric vehicle for electric vehicles. Background Technology

[0002] Dual-motor drive technology can improve the overall efficiency of a vehicle, thereby increasing its driving range. Currently, one major type of dual-motor drive technology uses a power split approach, with one motor responsible for front-wheel drive and the other for rear-wheel drive. This type of dual-motor drive can reuse high-efficiency operating areas. Although two motors are used, the energy system, such as a battery or supercapacitor, is generally still a single system, meaning that the same energy system powers both motors simultaneously.

[0003] For B+C hybrid power systems, such as batteries plus supercapacitors, the addition of supercapacitors outside the batteries allows the high energy recovery efficiency and suitability for high current output of supercapacitors to be utilized, effectively supplementing single-battery systems and mitigating aging and degradation caused by over-discharge or overcharge of batteries.

[0004] The existing common B+C energy distribution strategy, under the same power demand, the supercapacitor outputs the same or a fixed ratio of power to the front and rear wheels. This does not take into account the different energy recovery amounts of the front and rear wheels under different terrains. Therefore, it does not control the supercapacitor's energy output according to the difference in the energy that the front and rear wheels may recover based on the terrain, and cannot achieve optimized energy storage space and maximize energy recovery. Summary of the Invention

[0005] The main objective of this invention is to overcome the aforementioned deficiencies in the prior art and to propose an optimized energy distribution method, system, and electric vehicle for electric vehicles, thereby expanding the total capacity of supercapacitors and improving the recovery of braking or coasting energy.

[0006] The present invention adopts the following technical solution:

[0007] An optimized energy distribution method for an electric vehicle, characterized in that: based on the battery supplying power or recovering energy for the front-wheel drive unit and / or the rear-wheel drive unit, a first supercapacitor and a second supercapacitor are provided. The first supercapacitor is used to supply power or recover energy for the rear-wheel drive unit of the electric vehicle, and the second supercapacitor is used to supply power or recover energy for the front-wheel drive unit of the electric vehicle. The specific distribution method includes the following steps:

[0008] Step 1) Determine whether the remaining charge of the first supercapacitor and the second supercapacitor is greater than the preset threshold. If yes, proceed to Step 2); otherwise, repeat this step.

[0009] Step 2) Obtain the topographic map of the road ahead of the electric vehicle's location using the electronic horizon system, and predict whether the road ahead of the electric vehicle's location has a continuous slope. If so, proceed to Step 3).

[0010] Step 3) Based on the continuous slope value of the road ahead of the electric vehicle, predict the front and rear wheel braking force distribution ratio when the electric vehicle brakes at the continuous slope position of the road ahead. Based on the front and rear wheel braking force distribution ratio, pre-allocate the current power output ratio of the first supercapacitor and the second supercapacitor, and return to step 1).

[0011] Preferably, in step 3), the distribution relationship of the front and rear wheel braking forces when braking at the continuous slope position of the road ahead is predicted based on the continuous slope value of the road ahead, and the braking distribution ratio is calculated based on the distribution relationship of the front and rear wheel braking forces.

[0012] Preferably, the distribution relationship of the braking force between the front and rear wheels includes the following:

[0013]

[0014] , These are the normal forces acting on the front and rear wheels, respectively. For the weight of the electric vehicle; , These are the distances from the center of gravity of the electric vehicle to the front and rear axles, respectively. This refers to the wheelbase of the electric vehicle. The height of the electric vehicle's center of gravity; Braking intensity is the ratio of the deceleration caused by braking of an electric vehicle to the acceleration due to gravity. This represents the continuous slope value.

[0015] Preferably, the front and rear wheel braking force distribution ratio is:

[0016]

[0017] in , These represent the braking forces applied to the front and rear wheels, respectively.

[0018] Preferably, in step 2), if there is no continuous sloping terrain on the road ahead, a conventional dual-motor energy distribution strategy is adopted.

[0019] An optimized energy distribution system for an electric vehicle includes a battery, a front-wheel drive unit, and a rear-wheel drive unit. The battery supplies power to the front-wheel drive unit and / or the rear-wheel drive unit of the electric vehicle or recovers electrical energy. The system is characterized by further including a first supercapacitor, a second supercapacitor, and an energy control device. The energy control device is connected to an electronic horizon system, the battery, the first supercapacitor, and the second supercapacitor, and uses the optimized energy distribution method for the electric vehicle to allocate the current power output ratio between the first supercapacitor and the second supercapacitor.

[0020] A dual-motor driven electric vehicle includes a vehicle body, characterized in that it also includes the aforementioned optimized energy distribution system for an electric vehicle.

[0021] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In this invention, for dual-motor electric vehicles, two supercapacitors are used to separately recover energy output from the front and rear wheels, expanding the total capacity of the supercapacitors. Furthermore, under the prediction of the electronic horizon system, different supercapacitor energy output distribution ratios are formulated according to the mechanical characteristics of the front and rear wheels in different terrain environments. This ensures that after reaching the predicted terrain, a reasonable energy storage space can be freed up, so as to recover as much braking or gliding energy as possible and achieve a more ideal economic effect.

[0023] 2. In this invention, the front and rear wheel braking force distribution relationship is first predicted based on the continuous slope value ahead. The braking distribution ratio is calculated based on the front and rear wheel braking force distribution relationship, and this is used as the basis for the power output distribution of the first supercapacitor and the second supercapacitor. This ensures that the proportion of the available storage space of the front and rear axle supercapacitors is the same as the proportion of energy that can be recovered by braking after reaching the terrain ahead, thus avoiding the waste of energy recovered after the braking force is generated. Attached Figure Description

[0024] Figure 1 This is a flowchart of the present invention;

[0025] Figure 2 This is a system diagram of the present invention;

[0026] in:

[0027] 10. Battery; 20. First differential; 30. First motor; 40. First supercapacitor; 50. Second differential; 60. Second motor; 70. Second supercapacitor; 80. Energy control device; 90. Electronic horizon system.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0029] The present invention will be further described below through specific embodiments.

[0030] See Figure 1 , Figure 2 An optimized energy distribution method for an electric vehicle, based on the battery supplying power or recovering energy for the front-wheel drive unit and / or the rear-wheel drive unit, includes a first supercapacitor 40 and a second supercapacitor 70. The first supercapacitor 40 supplies power or recovers energy for the rear-wheel drive unit of the electric vehicle, and the second supercapacitor 70 supplies power or recovers energy for the front-wheel drive unit of the electric vehicle. The specific distribution method includes the following steps:

[0031] Step 1) Determine whether the remaining charge (SOC) of the first supercapacitor 40 and the second supercapacitor 70 is greater than the preset threshold. If so, it is necessary to consider making as much storage space as possible for the future possible recovery of braking energy and proceed to Step 2). Otherwise, repeat this step.

[0032] Step 2) Obtain the road topography map ahead of the electric vehicle's location through the electronic horizon system 90, predict whether the road ahead of the electric vehicle's location has a continuous slope, and if so, obtain the continuous slope value and proceed to step 3) Predictive optimization of energy allocation strategy.

[0033] In this step, if there is no continuous and stable terrain ahead, the conventional energy distribution strategy is adopted. The conventional energy analysis strategy is the well-known dual-motor energy distribution strategy, such as the B+C energy distribution strategy. Under the same power demand, the power output of the supercapacitor to the front and rear wheels is the same or a fixed ratio. At this time, the first supercapacitor 40 and the second supercapacitor 70 only play a simple role in increasing the capacity.

[0034] Step 3) Based on the continuous slope value of the road ahead of the electric vehicle, predict the front and rear wheel braking force distribution ratio when the electric vehicle brakes at the continuous slope position of the road ahead. Based on the braking force distribution ratio, pre-allocate the current power output ratio of the first supercapacitor 40 and the second supercapacitor 70, and return to step 1).

[0035] In this step, the distribution relationship of braking force between the front and rear wheels when braking at the continuous slope position of the road ahead is predicted based on the continuous slope value of the road ahead, and the distribution ratio of braking force is calculated based on the distribution relationship of braking force between the front and rear wheels.

[0036] The distribution of braking force between the front and rear wheels includes the following:

[0037]

[0038] , These are the normal forces acting on the front and rear wheels, respectively. For the weight of the electric vehicle; , These are the distances from the center of gravity of the electric vehicle to the front and rear axles, respectively. This refers to the wheelbase of the electric vehicle. The height of the electric vehicle's center of gravity; Braking intensity is the ratio of the deceleration caused by braking of an electric vehicle to the acceleration due to gravity. This represents the continuous slope value.

[0039] According to common knowledge, the braking force acting on the front and rear wheels is proportional to their respective normal forces. , At this time, the ground adhesion conditions will be fully utilized, the electric vehicle's braking efficiency will be highest, and its stability will be best. This means that when braking is required at a point on a continuous slope ahead, the front and rear wheel braking force ratio will satisfy the following braking force distribution ratio:

[0040]

[0041] in , These represent the braking forces acting on the front and rear wheels, respectively. As the formula shows, the braking force distribution ratio varies with the slope; when the slope is steeper, the braking force distribution... When <0, The front wheel braking force should be greater than the rear wheel braking force; conversely, when the uphill slope is steep... The braking force of the rear wheels should be greater than that of the front wheels.

[0042] Different braking force ratios result in different proportions of recovered electrical energy during braking. Therefore, based on the predicted braking ratio ahead, the current power output of the first supercapacitor 40 and the second supercapacitor 70 is appropriately allocated in advance. This ensures that the proportion of available storage space in the supercapacitors on the front and rear axles is the same as the proportion of energy recovered during braking upon reaching the terrain ahead. This prevents a situation where, after the braking force generates recovered electrical energy, the supercapacitor capacity is mismatched due to the different amounts of energy recovered from the front and rear wheels, resulting in some supercapacitors being full and unable to recover energy, thus avoiding waste.

[0043] See Figure 2 The present invention also proposes an optimized energy distribution system for an electric vehicle, including a battery 10, a front-wheel drive unit, a rear-wheel drive unit, a first supercapacitor 40, a second supercapacitor 70, and an energy control device 80, etc. The rear-wheel drive unit includes a first differential 20 and a second motor 60, etc., for driving the rear wheels. The front-wheel drive unit includes a second differential 50 and a second motor 60, etc., for driving the front wheels.

[0044] The battery 10 supplies power or recovers electrical energy for the front-wheel drive unit and / or the rear-wheel drive unit. That is, the battery 10 can supply power to the first motor 30 or the second motor 60 alone, or simultaneously supply power to the first motor 30 and the second motor 60, so that the motors can convert electrical energy into mechanical energy for vehicle drive. The battery 10 can recover electrical energy generated by the conversion of mechanical energy during braking or coasting of the first motor 30 or the second motor 60 alone, or simultaneously recover electrical energy generated by the first motor 30 and the second motor 60.

[0045] The first supercapacitor 40 is physically connected only to supply power to the first motor 30 or to recover electrical energy from the first motor 30. The second supercapacitor 70 is physically connected only to supply power to the second motor 60 or to recover electrical energy from the second motor 60. The energy control device 80 is connected to the electronic horizon system 90, the battery 10, the first supercapacitor 40, and the second supercapacitor 70, and is used to distribute electrical energy from the battery 10, the first supercapacitor 40, and the second supercapacitor 70 to the motor, and to distribute the recovered electrical energy from the motor to the battery 10, the first supercapacitor 40, and the second supercapacitor 70 for storage.

[0046] The system of this invention employs the aforementioned optimized energy distribution method for an electric vehicle to allocate the power output ratio between the first supercapacitor 40 and the second supercapacitor 70. It can optimize the energy distribution strategy of the battery 10, the first supercapacitor 40, and the second supercapacitor 70 based on the road terrain slope information provided by the electronic horizon system 90 and combined with the predicted road terrain slope information, thereby improving the vehicle's economy or comfort.

[0047] Based on this, the present invention also proposes a dual-motor driven electric vehicle, including the vehicle body and the above-mentioned optimized energy distribution system of the electric vehicle. The use of dual supercapacitors not only increases the energy storage capacity, but also optimizes the energy output ratio of the front and rear wheel supercapacitors according to the predicted terrain conditions ahead, ensuring that a reasonable energy storage space can be freed up after reaching the predicted terrain, and recovering as much energy as possible, thus having a greater energy-saving advantage.

[0048] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A method for optimizing energy distribution in an electric vehicle, characterized by: On the basis of the battery powering or recovering electric energy for the front-wheel drive device and / or the rear-wheel drive device, a first super capacitor and a second super capacitor are arranged, the first super capacitor is used for powering or recovering electric energy for the rear-wheel drive device of the electric vehicle, and the second super capacitor is used for powering or recovering electric energy for the front-wheel drive device of the electric vehicle; the specific distribution method comprises the following steps: Step 1) judging whether the residual electric quantity of the first super capacitor and the second super capacitor is greater than a preset threshold value, if yes, entering step 2), if not, repeating the step; Step 2) obtaining a road topographic map in front of a position of the electric vehicle through an electronic horizon system, and predicting whether the road in front of the position of the electric vehicle has a continuous slope, if yes, entering step 3); Step 3) predicting a distribution ratio of front and rear wheel braking forces when the electric vehicle brakes at a continuous slope position of the road in front according to a continuous slope value of the road in front of the position of the electric vehicle, and distributing a ratio of electric power outputs of the first super capacitor and the second super capacitor in advance according to the distribution ratio of the front and rear wheel braking forces, and returning to step 1); In step 3), the distribution relationship of the front and rear wheel braking forces when braking at the continuous slope position of the road in front is predicted according to the continuous slope value of the road in front, and the braking distribution ratio is calculated according to the distribution relationship of the front and rear wheel braking forces. The distribution relationship of the front and rear wheel braking forces comprises the following: ； , are the normal forces on the front and rear wheels, respectively, is the gravity of the electric vehicle; , are the distances from the front and rear axles to the center of mass of the electric vehicle, respectively; is the wheelbase of the electric vehicle; is the height of the center of mass of the electric vehicle; is the braking intensity, which is the ratio of the deceleration caused by braking to the acceleration of gravity, is the continuous grade value; The distribution ratio of the front and rear wheel braking forces is: ； wherein , are the braking forces on the front and rear wheels, respectively.

2. The method for optimizing energy distribution of an electric vehicle as claimed in claim 1, wherein: In step 2), if the road in front has no continuous slope topography, a conventional dual-motor energy distribution strategy is adopted.

3. An optimized energy distribution system for an electric vehicle, comprising a battery, a front wheel drive device and a rear wheel drive device, the battery supplies power or recovers electric energy for the front wheel drive device and / or the rear wheel drive device of the electric vehicle, characterized in that: The first super capacitor, the second super capacitor and the energy control device are further included. The energy control device is connected with the electronic horizon system, the battery, the first super capacitor and the second super capacitor, and adopts the energy distribution method of the electric vehicle of any one of claims 1 to 2 to distribute the ratio of electric power outputs of the first super capacitor and the second super capacitor.

4. A dual motor drive electric vehicle comprising a vehicle body, characterized by: The energy distribution system of the electric vehicle of claim 3 is further included.

Images