Method and system for electric energy discharge control of an electric transport vehicle

Abstract

The application discloses a kind of electric transport vehicle electric energy discharge control method and system, it is related to new energy automobile technical field.Based on traditional DCDC converter, additional energy discharge loop is increased, and it is used for the energy discharge of fuel cell transport vehicle when emergency deceleration, brake;Whole vehicle control method is proposed, to ensure the normal safe and stable operation of whole vehicle and parts;The present application has little change to hardware, more is the change to control method and software, the cost of whole vehicle is lower, and the practicality is stronger.When the output power of fuel cell stack decreases and the power absorption rate of whole vehicle is lower, the power of fuel cell stack is discharged through energy discharge loop, so as to ensure the normal work of whole vehicle and parts.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and more specifically to a method and system for controlling the discharge of electrical energy in an electric transport vehicle. Background Technology

[0002] Fuel cell transport vehicles are a new type of new energy electric transport vehicle. They generate electricity through a chemical reaction between fuel and air in a reactor, driving the vehicle and supplying power to its high-voltage loads. Currently, a common drawback of fuel cell stacks in fuel cell transport vehicles is that their output power cannot change abruptly; their power change rate is low. This leads to a problem: when the stack is outputting high power, if the transport vehicle suddenly decelerates or brakes, the vehicle's power demand is low, but the fuel cell's output power cannot drop suddenly. This can cause the following malfunctions: 1. The vehicle cannot brake or decelerate quickly; 2. The regenerative power of the power battery is too high, leading to overcharging and damage; 3. The fuel cell stack cannot release power in time, causing it to stall. To address these issues, the industry generally equips fuel cell transport vehicles with high-capacity or high-power batteries to absorb excess power from the fuel cell stack. However, equipping them with high-capacity or high-power batteries results in excessively high vehicle costs. Furthermore, high-capacity or high-power batteries are often bulky, increasing the design complexity of the transport vehicle. Summary of the Invention

[0003] In view of this, the present invention provides a method and system for controlling the discharge of electrical energy in an electric transport vehicle, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: On one hand, it provides a method for controlling the discharge of electrical energy in an electric transport vehicle, the specific steps of which include the following: S1, Real-time detection of driver's needs, drive / feedback power P M0 Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; S2. Calculate the power P that the high-voltage accessories need to consume in the next moment based on the current state of the vehicle. HV0 ; S3, via the drive / feedback power P M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HVCalculate the total power reduction of the vehicle, ΔP; S4. Compare the total vehicle power reduction value ΔP with the allowable power reduction value ΔP. FCS Take the difference to obtain the first difference value; S5. Compare the first difference with the current maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results.

[0005] Preferably, the drive / feedback power P is acquired in real time based on the opening of the brake pedal and accelerator pedal. M0 .

[0006] Preferably, the calculation process for the total power reduction value ΔP of the vehicle is as follows: △P=P M +P HV -P; Among them, P M P represents the current output power of the electric drive system. HV P represents the power consumed by the high-voltage accessories, and P represents the total power demand of the entire vehicle. P = P0 M0 +P HV0 P M0 For drive / feedback power, P HV0 This represents the power required by the high-voltage accessories.

[0007] Preferably, the specific process of determining the power consumption of the remaining energy discharge circuit based on the comparison result is as follows: When the first difference ≥ P bat-char At that time, the vehicle requests the fuel cell stack output power to be P. FCS0 -△P FCS The output power of the full-bridge DC-DC converter circuit is P+P. bat-char The power consumed by the residual energy discharge circuit is ΔP - ΔP FCS -P bat-char ; When the first difference < P bat-char At that time, the vehicle requests the fuel cell stack output power to be P+kP. bat-char The output power of the full-bridge DC-DC converter circuit is P+kP. bat-char The remaining energy discharge circuit consumes 0 power, where k is the charging power coefficient, and its value ranges from 0 to k to 1.

[0008] On the other hand, an electric energy discharge control system for an electric transport vehicle is provided, including a data monitoring module, an accessory power module, a total power reduction calculation module, a difference calculation module, and a comparison module; wherein... The data monitoring module is used to detect the driver's required drive / feedback power P in real time. M0Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; The accessory power module is used to calculate the power P that the high-voltage accessory needs to consume in the next moment based on the current state of the vehicle. HV0 ; The total power reduction calculation module is used to calculate the total power reduction value based on the drive / feedback power P. M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HV Calculate the total power reduction of the vehicle, ΔP; The difference calculation module is used to compare the total power reduction value △P of the vehicle with the allowable power reduction value △P. FCS Take the difference to obtain the first difference value; The comparison module is used to compare the first difference with the maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results.

[0009] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an electric vehicle energy discharge control method and system, which has the following beneficial technical effects: the fuel cell vehicle can still stably accelerate or brake even when matched with a fuel cell stack with a low power reduction rate and a small power battery capacity and rechargeable power, ensuring the vehicle's power, safety and the driver's driving experience; and the hardware changes are minimal, with more changes to the control method and software, resulting in lower overall vehicle cost, strong practicality, and ensuring the normal, safe and stable operation of the vehicle and its components. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0011] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the residual energy discharge circuit of the present invention; Figure 3 This is a system structure diagram of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] This invention discloses a method for controlling the discharge of electrical energy in an electric transport vehicle, such as... Figure 1 As shown, the specific steps include the following: S1, Real-time detection of driver's needs, drive / feedback power P M0 Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; S2. Calculate the power P that the high-voltage accessories need to consume in the next moment based on the current state of the vehicle. HV0 ; S3, via drive / feedback power P M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HV Calculate the total power reduction of the vehicle, ΔP; S4. Compare the total power reduction value ΔP of the vehicle with the allowable power reduction value ΔP. FCS Take the difference to obtain the first difference value; S5. Compare the first difference with the current maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results.

[0014] Furthermore, based on the current state of the vehicle, calculate the power P that the high-voltage accessories need to consume in the next moment. HV0 Specifically, the power P that the high-voltage accessories need to consume in the next period is calculated by summing the current DC-DC output power, PTC power, air conditioning compressor power, and other high-voltage accessories. HV0 .

[0015] Furthermore, the drive / feedback power P is collected in real time based on the opening of the brake pedal and accelerator pedal. M0 .

[0016] Furthermore, the calculation process for the total power reduction ΔP of the vehicle is as follows: △P=P M +PHV -P; Among them, P M P represents the current output power of the electric drive system. HV P represents the power consumed by the high-voltage accessories, and P represents the total power demand of the entire vehicle. P = P0 M0 +P HV0 P M0 For drive / feedback power, P HV0 This represents the power required by the high-voltage accessories.

[0017] Furthermore, the specific process for determining the power consumption of the remaining energy discharge circuit based on the comparison results is as follows: When the first difference ≥ P bat-char At that time, the vehicle requests the fuel cell stack output power to be P. FCS0 -△P FCS The output power of the full-bridge DC-DC converter circuit is P+P. bat-char The power consumed by the residual energy discharge circuit is ΔP - ΔP FCS -P bat-char ; When the first difference < P bat-char At that time, the vehicle requests the fuel cell stack output power to be P+kP. bat-char The output power of the full-bridge DC-DC converter circuit is P+kP. bat-char The remaining energy discharge circuit consumes 0 power, where k is the charging power coefficient, and its value ranges from 0 to k to 1.

[0018] Specifically, the hardware circuit schematic used in this embodiment is as follows: Figure 2 As shown, the fuel cell stack is connected to the high-voltage circuit of the transport vehicle through a traditional full-bridge DC-DC converter circuit. Based on the traditional full-bridge DC-DC converter circuit, this embodiment of the invention adds an L2 secondary winding in parallel to the secondary winding L1 of its transformer, and connects a large capacitor and a resistor (or a separate resistor) in parallel with the L2 secondary winding to discharge the remaining energy of the fuel cell stack.

[0019] This invention has been applied to hydrogen fuel cell transport vehicles. In these vehicles, with the power battery's state of charge (SOC) at 70%, a sudden drop in total vehicle power demand from 120kW to 20kW results in a 100kW decrease. However, the fuel cell stack's allowable power reduction is only 30kW, and the maximum allowable charging power of the power battery is 60kW. At this point, the power output from the stack cannot be consumed by the vehicle's motor, high-voltage accessories, and the power battery. Without a residual energy discharge circuit, this would lead to overcurrent in the power battery, causing the vehicle to suddenly lose power. This invention enables safe and reliable rapid deceleration and braking of the transport vehicle.

[0020] On the other hand, an electric power discharge control system for electric transport vehicles is provided, such as... Figure 3 As shown, it includes a data monitoring module, an accessory power module, a total power reduction calculation module, a difference calculation module, and a comparison module; among which, The data monitoring module is used to detect the driver's required drive / feedback power P in real time. M0 Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; The accessory power module is used to calculate the power P that the high-voltage accessory needs to consume in the next moment based on the current state of the vehicle. HV0 ; The total power reduction calculation module is used to calculate the power reduction value P by driving / feedback power P. M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HV Calculate the total power reduction of the vehicle, ΔP; The difference calculation module is used to compare the total power reduction value △P of the vehicle with the allowable power reduction value △P. FCS Take the difference to obtain the first difference value; The comparison module is used to compare the first difference with the current maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results.

[0021] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0022] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the discharge of electrical energy in an electric transport vehicle, characterized in that, The specific steps include the following: S1, Real-time detection of driver's needs, drive / feedback power P M0 Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; S2. Calculate the power P that the high-voltage accessories need to consume in the next moment based on the current state of the vehicle. HV0 ; S3, via the drive / feedback power P M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HV Calculate the total power reduction of the vehicle, ΔP; S4. Compare the total vehicle power reduction value ΔP with the allowable power reduction value ΔP. FCS Take the difference to obtain the first difference value; S5. Compare the first difference with the current maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results. The calculation process for the total power reduction ΔP of the vehicle is as follows: △P=P M +P HV -P; Among them, P M P represents the current output power of the electric drive system. HV P represents the power consumed by the high-voltage accessories, and P represents the total power demand of the entire vehicle. P = P0 M0 +P HV0 P M0 For drive / feedback power, P HV0 This refers to the power consumed by the high-voltage accessories. The specific process for determining the power consumption of the remaining energy discharge circuit based on the comparison results is as follows: When the first difference ≥ P bat-char At that time, the vehicle requests the fuel cell stack output power to be P. FCS0 -△P FCS The output power of the full-bridge DC-DC converter circuit is P+P. bat-char The power consumed by the residual energy discharge circuit is ΔP - ΔP FCS -P bat-char ; When the first difference < P bat-char At that time, the vehicle requests the fuel cell stack output power to be P+kP. bat-char The output power of the full-bridge DC-DC converter circuit is P+kP. bat-char The remaining energy discharge circuit consumes 0 power, where k is the charging power coefficient, and its value ranges from 0 to k to 1.

2. The method for controlling the discharge of electrical energy in an electric transport vehicle according to claim 1, characterized in that, The drive / feedback power P is collected in real time based on the opening of the brake pedal and accelerator pedal. M0 .

3. An electric energy discharge control system for an electric transport vehicle, characterized in that, It includes a data monitoring module, an accessory power module, a total power reduction calculation module, a difference calculation module, and a comparison module; among which, The data monitoring module is used to detect the driver's required drive / feedback power P in real time. M0 Fuel cell stack output power P FCS0 and the allowable reduction in power ΔP FCS The current output power P of the electric drive system M Power consumption P of high voltage accessories HV ; The accessory power module is used to calculate the power P that the high-voltage accessory needs to consume in the next moment based on the current state of the vehicle. HV0 ; The total power reduction calculation module is used to calculate the total power reduction value based on the drive / feedback power P. M0 The power P required by the high-voltage accessories HV0 The current output power P of the electric drive system M Power consumption P of high-voltage accessories HV Calculate the total power reduction of the vehicle, ΔP; The difference calculation module is used to compare the total power reduction value △P of the vehicle with the allowable power reduction value △P. FCS Take the difference to obtain the first difference value; The comparison module is used to compare the first difference with the maximum allowable charging power P of the power battery. bat-char The comparison is performed, and the power consumed by the remaining energy discharge circuit is determined based on the comparison results. The calculation process for the total power reduction ΔP of the vehicle is as follows: △P=P M +P HV -P; Among them, P M P represents the current output power of the electric drive system. HV P represents the power consumed by the high-voltage accessories, and P represents the total power demand of the entire vehicle. P = P0 M0 +P HV0 P M0 For drive / feedback power, P HV0 This refers to the power consumed by the high-voltage accessories. The specific process for determining the power consumption of the remaining energy discharge circuit based on the comparison results is as follows: When the first difference ≥ P bat-char At that time, the vehicle requests the fuel cell stack output power to be P. FCS0 -△P FCS The output power of the full-bridge DC-DC converter circuit is P+P. bat-char The power consumed by the residual energy discharge circuit is ΔP - ΔP FCS -P bat-char ; When the first difference < P bat-char At that time, the vehicle requests the fuel cell stack output power to be P+kP. bat-char The output power of the full-bridge DC-DC converter circuit is P+kP. bat-char The remaining energy discharge circuit consumes 0 power, where k is the charging power coefficient, and its value ranges from 0 to k to 1.

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