CN114228566B - Composite power supply system and energy management method thereof - Google Patents

Abstract

The present invention discloses a composite power supply system and an energy management method thereof, belonging to the field of power supply management technology. The present invention monitors the real-time SOC value of the supercapacitor through a first monitor and updates the real-time SOC value of the supercapacitor; the second monitor monitors the real-time SOC value of the lithium battery pack and updates the real-time SOC value of the lithium battery pack, obtains the acceleration of the vehicle under the current working condition, and determines the required power of the vehicle provided by the supercapacitor and/or the lithium battery pack through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, implements different energy management methods according to the acceleration of the vehicle, monitors the battery power in real time and updates through the first and second monitors, reduces the damage to the lithium battery pack caused by long-term high-power discharge, and maximizes the cycle life of the lithium battery.

Description

Composite power supply system and energy management method thereof

Technical Field

The present invention relates to the technical field of power management, and in particular to a composite power system and an energy management method thereof.

Background technique

At present, in the development process of pure electric vehicles, energy management has become the most important core technology of the whole vehicle, and most pure electric vehicles use composite power sources as the energy storage system of the vehicle. Among them, lithium batteries as power batteries have the characteristics of high specific energy, and supercapacitors have the characteristics of high specific power. The two complement each other perfectly, and the composite power source thus formed can well meet the power demand of the load. However, most cars have the problem of improper energy management of composite power sources during use, resulting in low energy utilization and causing the lithium battery in the composite power source to provide the required power for a long time while ignoring whether the battery discharge limit has been reached, thereby affecting the cycle life of the lithium battery.

The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art.

Summary of the invention

The main purpose of the present invention is to provide a composite power supply system and an energy management method thereof, aiming to solve the technical problem of low cycle life of lithium battery packs in the prior art.

To achieve the above object, the present invention provides a composite power supply system, the system comprising: a composite power supply, a first monitor and a second monitor, the composite power supply comprising a supercapacitor and a lithium battery pack, the first monitor is connected in parallel with the supercapacitor, the second monitor is connected in parallel with the lithium battery pack, the supercapacitor and the lithium battery pack are respectively connected to a motor of a vehicle;

The supercapacitor is used to provide power to the motor of the vehicle and filter the current generated during the operation of the vehicle;

The lithium battery pack is used to provide power to power the motor of the vehicle;

The first monitor is used to monitor the real-time SOC value of the supercapacitor and update the real-time SOC value of the supercapacitor;

The second monitor is used to monitor the real-time SOC value of the lithium battery pack and update the real-time SOC value of the lithium battery pack.

Optionally, the system further includes: a first bidirectional DC/DC converter and a second bidirectional DC/DC converter, wherein a first end of the first bidirectional DC/DC converter is connected to the supercapacitor, a second end of the first bidirectional DC/DC converter is connected to a motor of a vehicle, a first end of the second bidirectional DC/DC converter is connected to the lithium battery pack, and a second end of the bidirectional DC/DC converter is connected to the motor of the vehicle;

The first bidirectional DC/DC converter is used to adjust the charging and discharging voltage of the supercapacitor;

The second bidirectional DC/DC converter is used to decouple the lithium battery pack to prevent the lithium battery pack from being affected by peak power and ensure that the charging and discharging current of the lithium battery pack is stable.

In addition, to achieve the above-mentioned purpose, the present invention provides a composite power system energy management method, the method is applied to the composite power system described above, the composite power system comprises: a supercapacitor, a lithium battery pack, a first bidirectional DC/DC converter and a second bidirectional DC/DC converter, the method comprises the following steps:

Get the acceleration of the car under the current working conditions;

The super capacitor and/or the lithium battery pack is used to provide the required power of the vehicle according to the acceleration through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter.

Optionally, before determining that the supercapacitor and/or the lithium battery pack provides required power for the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, the method further includes:

Collecting basic parameter information of the supercapacitor and the lithium battery pack;

Setting the charge and discharge thresholds of the supercapacitor and the lithium battery pack based on the basic parameter information;

The SOC values of the supercapacitor and the lithium battery pack are obtained.

Optionally, determining, according to the acceleration, through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, that the supercapacitor and/or the lithium battery pack provides required power for the vehicle includes:

Comparing the acceleration with a preset acceleration threshold value;

When the acceleration is greater than the preset acceleration threshold value, the SOC value of the supercapacitor and/or the SOC value of the lithium battery pack is determined to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter.

Optionally, after comparing the acceleration with a preset acceleration threshold value, the method further includes:

When the acceleration is less than or equal to the preset acceleration threshold value and greater than zero and/or equal to zero, the required power of the vehicle is provided by the second bidirectional DC/DC converter and the SOC value of the lithium battery pack.

Optionally, the charge and discharge thresholds of the supercapacitor include: a first threshold, a second threshold and a third threshold, the first threshold is less than the second threshold, and the second threshold is less than the third threshold;

The method of determining, according to the acceleration, through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, that the supercapacitor and/or the lithium battery pack provides required power for the vehicle comprises:

When the SOC value of the supercapacitor is greater than the first threshold and less than the second threshold, the required power of the vehicle is provided by the first bidirectional DC/DC converter, the second bidirectional DC/DC converter, the SOC value of the lithium battery pack and the SOC value of the supercapacitor.

Optionally, determining, according to the acceleration, through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, that the supercapacitor and/or the lithium battery pack provides required power for the vehicle includes:

When the SOC value of the supercapacitor is greater than zero and less than the first threshold, the required power of the vehicle is provided by the second bidirectional DC/DC converter and the SOC value of the lithium battery pack.

Optionally, determining, according to the acceleration, through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, that the supercapacitor and/or the lithium battery pack provides required power for the vehicle includes:

When the SOC value of the supercapacitor is greater than the second threshold value and less than the third threshold value, the required power of the vehicle is provided by the first bidirectional DC/DC converter and the SOC value of the supercapacitor.

Optionally, the composite power supply system comprises: a first monitor and a second monitor;

After determining that the supercapacitor and/or the lithium battery pack provides the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, the method further includes:

Monitoring the charging and discharging state of the supercapacitor under the current working condition by the first monitor;

Monitoring the charge and discharge status of the lithium battery pack under the current working condition through the second monitor;

When the charge and discharge values of the super capacitor and the lithium battery pack reach the charge and discharge thresholds, the SOC values of the super capacitor and the lithium battery pack are re-input through the first monitor and the second monitor, and the monitoring data is updated in real time.

The present invention arranges a supercapacitor, a lithium battery pack, a first monitor and a second monitor in a composite power supply system, wherein the first monitor is connected in parallel with the supercapacitor, the second monitor is connected in parallel with the lithium battery pack, and the supercapacitor and the lithium battery pack are respectively connected to the motor of the vehicle. The supercapacitor is used to provide power to the motor of the vehicle and filter the current generated by the vehicle during operation; the lithium battery pack is used to provide power to the motor of the vehicle; the first monitor is used to monitor the real-time SOC value of the supercapacitor and update the real-time SOC value of the supercapacitor The second monitor is used to monitor the real-time SOC value of the lithium battery pack and update the real-time SOC value of the lithium battery pack, by obtaining the acceleration of the vehicle under the current working condition, and according to the acceleration, the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter are used to determine the required power of the vehicle provided by the supercapacitor and/or the lithium battery pack, and different energy management methods are implemented according to the acceleration of the vehicle. The power is monitored and updated in real time by the first and second monitors, so as to reduce the damage of long-term high-power discharge to the lithium battery pack and maximize the cycle life of the lithium battery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a composite power supply system of the present invention;

FIG2 is a schematic diagram of a flow chart of a first embodiment of a composite power system energy management method according to the present invention;

3 is a schematic diagram of a flow chart of a second embodiment of a composite power system energy management method according to the present invention;

FIG4 is a schematic flow chart of a third embodiment of a composite power system energy management method according to the present invention;

5 is a schematic diagram of a flow chart of a fourth embodiment of a composite power system energy management method according to the present invention;

FIG. 6 is a flow chart of a fifth embodiment of a composite power system energy management method according to the present invention.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

Referring to FIG. 1 , FIG. 1 is a schematic diagram of the structure of the composite power supply system of the present invention.

As shown in FIG1 , the composite power supply system of the present invention includes: a composite power supply, a first monitor A1 and a second monitor A2, the composite power supply includes a supercapacitor 10 and a lithium battery pack 20, the first monitor A1 is connected in parallel with the supercapacitor 10, the second monitor A2 is connected in parallel with the lithium battery pack 20, the supercapacitor 10 and the lithium battery pack 20 are respectively connected to the motor 30 of the vehicle; the supercapacitor 10 is used to provide power to power the motor 30 of the vehicle and filter the current generated by the vehicle during operation; the lithium battery pack 20 is used to provide power to power the motor 30 of the vehicle; the first monitor A1 is used to monitor the real-time SOC value of the supercapacitor 10 and update the real-time SOC value of the supercapacitor 10; the second monitor A2 is used to monitor the real-time SOC value of the lithium battery pack 20 and update the real-time SOC value of the lithium battery pack 20.

It should be noted that the execution subject of this embodiment may be a controller of the composite power supply energy management, or other devices that can achieve the same or similar functions, and this embodiment does not limit this.

In a specific implementation, the composite power source refers to a power source formed by the combination of a supercapacitor 10 and a lithium battery pack 20, and the motor 20 of the vehicle is powered by the superpower source 10 and the lithium battery pack 20 to meet the driving needs of the vehicle. The composite power supply system is composed of a supercapacitor 10, a lithium battery pack 20, a first monitor A1 and a second monitor A2, and is mainly used in a fully active system. SOC refers to the state of charge, and the SOC value is the remaining power value of the battery or supercapacitor. The supercapacitor 10 is connected in parallel with the first monitor A1, and the first monitor A1 is used to monitor the real-time SOC value of the supercapacitor 10. The lithium battery pack 20 is connected in parallel with the second monitor A2, and the second monitor A2 is used to monitor the real-time SOC value of the lithium battery pack. The long-term, high-power discharge of the supercapacitor 10 and the lithium battery pack 20 is monitored in real time by the first monitor A1 and the second monitor A2, and the SOC threshold of the charge and discharge of the supercapacitor 10 and the lithium battery pack 20 is updated in real time. After the supercapacitor 10 and the lithium battery pack 20 consume the energy of the vehicle's motor 30 by discharging, the SOC value of the supercapacitor 10 and the lithium battery pack 20 can be re-entered and corrected, which can protect the lithium battery pack 20 to the greatest extent, extend its cycle life and improve energy utilization. The supercapacitor 10 is connected to the system alone, which can play the role of a low-pass filter, and reasonably recover the high-frequency current generated during the rapid acceleration or deceleration braking of the vehicle, so as to achieve the purpose of improving energy utilization and reducing the operating cost of the composite power supply.

In this embodiment, the system also includes: a first bidirectional DC/DC converter B1 and a second bidirectional DC/DC converter B2, wherein a first end of the first bidirectional DC/DC converter B1 is connected to the supercapacitor 10, a second end of the first bidirectional DC/DC converter B1 is connected to the motor 30 of the vehicle, a first end of the second bidirectional DC/DC converter B2 is connected to the lithium battery pack 20, and a second end of the second bidirectional DC/DC converter B2 is connected to the motor 30 of the vehicle; the first bidirectional DC/DC converter B1 is used to adjust the charging and discharging voltage of the supercapacitor 10; the second bidirectional DC/DC converter B2 is used to decouple the lithium battery pack 20 to ensure that the charging and discharging current of the lithium battery pack 20 is stable.

It should be understood that the first end of the first bidirectional DC/DC converter B1 is connected to the supercapacitor 10, and the charging and discharging terminal voltage of the supercapacitor can be adjusted, so that the lithium battery pack 20 and the supercapacitor 10 can work together better and ensure that the power supply voltage is always within a stable and controllable range. The first end of the second bidirectional DC/DC converter B2 is connected to the lithium battery pack 20, and the batteries in the lithium battery pack 20 in the fully active structure can be decoupled to prevent the lithium batteries in the lithium battery pack 20 from being affected by the peak power, ensure that the charging and discharging current of the lithium battery is stable, reduce current loss, improve energy utilization, and also help to extend the service life of the lithium battery.

The present invention arranges a supercapacitor, a lithium battery pack, a first monitor and a second monitor in a composite power supply system, wherein the first monitor is connected in parallel with the supercapacitor, the second monitor is connected in parallel with the lithium battery pack, the supercapacitor and the lithium battery pack are respectively connected to the motor of the vehicle, the supercapacitor is used to provide power to the motor of the vehicle and filter the current generated by the vehicle during operation; the lithium battery pack is used to provide power to the motor of the vehicle; the first monitor is used to monitor the real-time SOC value of the supercapacitor and update the real-time SOC value of the supercapacitor; the second monitor is used to monitor the real-time SOC value of the lithium battery pack and update the real-time SOC value of the lithium battery pack, by obtaining the acceleration of the vehicle under the current working condition, according to the acceleration, through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, determine the required power provided by the supercapacitor and/or the lithium battery pack to the vehicle, monitor the power of the composite power supply in real time through the first and second monitors and update the monitoring data in real time, thereby greatly improving the energy utilization rate.

An embodiment of the present invention provides a composite power system energy management method. Referring to FIG. 2 , FIG. 2 is a flow chart of a first embodiment of a composite power system energy management method of the present invention.

In this embodiment, the composite power system includes: a supercapacitor, a lithium battery pack, a first bidirectional DC/DC converter and a second bidirectional DC/DC converter, and the composite power system energy management method includes the following steps:

Step S10: Obtain the acceleration of the vehicle under the current working condition.

It should be understood that the current operating condition refers to the current operating condition of the vehicle, which may include: rainy road surface, snowy road surface, icy road surface, asphalt road surface, dry road surface, etc., or other driving conditions, which are not limited in this embodiment. The acceleration of the vehicle refers to the acceleration of the vehicle under the current operating condition. The acceleration of the vehicle is different for different operating conditions and road surfaces, and the energy management method for the vehicle is also different.

Step S20: Determine the required power of the vehicle provided by the supercapacitor and/or the lithium battery pack according to the acceleration through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter.

In a specific implementation, under different accelerations, the corresponding energy management methods are different. The first and second bidirectional DC/DC converters can realize bidirectional transmission of energy, change the direction of input and output currents, and determine, based on the magnitude of acceleration, whether the current power demand of the vehicle is provided by a supercapacitor, a lithium battery pack, or both a supercapacitor and a lithium battery pack.

It should be noted that if the acceleration of the car is very large under the current operating conditions, it may be necessary for both supercapacitors and lithium battery packs to provide the power required for the current driving of the car.

This embodiment obtains the acceleration of the vehicle under the current working condition; determines the required power of the vehicle provided by the supercapacitor and/or the lithium battery pack according to the acceleration through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, obtains the acceleration of the vehicle under the current working condition, determines the required power of the vehicle provided by the supercapacitor and/or the lithium battery pack according to the acceleration through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, performs different energy management for different accelerations, and greatly improves energy utilization.

Refer to FIG. 3 , which is a flow chart of a second embodiment of a composite power system energy management method according to the present invention.

Based on the first embodiment described above, the composite power system energy management method of this embodiment further includes, before step S20:

Step S21: Collecting basic parameter information of the supercapacitor and the lithium battery pack.

In this embodiment, the basic parameter information includes at least one of the electromotive force, rated capacity, rated voltage, open circuit voltage, internal resistance, charge and discharge rate, impedance, life and self-discharge rate of the supercapacitor and the lithium battery pack. By collecting the basic parameter information of the supercapacitor and the lithium battery pack, the life, rated capacity and other information of the supercapacitor and the lithium battery pack can be obtained, which is convenient for better understanding the working status of the supercapacitor and the lithium battery pack and facilitating the management of the charging and discharging status.

Step S22: setting the charge and discharge thresholds of the supercapacitor and the lithium battery pack based on the basic parameter information.

It should be noted that the charge and discharge threshold refers to the minimum charge, maximum charge, maximum discharge, and minimum discharge of the supercapacitor and lithium battery pack. The basic parameter information can be used to know the optimal charge and discharge state of the supercapacitor and lithium battery pack. The charge and discharge thresholds of the supercapacitor and lithium battery pack can be set according to this state. For example, the charge and discharge threshold of the lithium battery pack is set to [0.3, 0.95], indicating that the discharge SOC threshold of the lithium battery pack is 30% of the total capacity of the lithium battery pack, and the charge SOC threshold is 95% of the total capacity of the lithium battery pack. The charge and discharge threshold of the supercapacitor is set to [0.1, 0.6, 0.9], indicating that the charge and discharge SOC threshold of the supercapacitor is 10% of the total capacity of the supercapacitor. The charge threshold of the supercapacitor can be 90% or 60%, which can be set and changed according to the specific acceleration of the vehicle. Due to the high power of the supercapacitor, high-power and long-term discharge can be performed.

It should be understood that after the charge and discharge SOC thresholds of the supercapacitor and the lithium battery pack are set, the set charge and discharge SOC thresholds of the supercapacitor can be input into the first monitor for monitoring, and the set charge and discharge SOC thresholds of the lithium battery pack can be input into the second monitor for monitoring. When the current SOC values of the supercapacitor and the lithium battery pack reach the set charge and discharge thresholds, corresponding energy management can be performed.

Step S23: Obtain the SOC values of the supercapacitor and the lithium battery pack.

In a specific implementation, the SOC values of the supercapacitor and the lithium battery pack can be obtained by monitoring the first monitor and the second monitor, and the vehicle motor can be powered by the real-time SOC values of the supercapacitor and the lithium battery pack.

This embodiment collects basic parameter information of the supercapacitor and the lithium battery pack; sets the charge and discharge thresholds of the supercapacitor and the lithium battery pack based on the basic parameter information; obtains the SOC value of the supercapacitor and the lithium battery pack, and obtains information such as the battery capacity and service life of the supercapacitor and the lithium battery pack by acquiring the basic parameter information of the supercapacitor and the lithium battery pack. The charge and discharge thresholds of the supercapacitor and the lithium battery pack can be set, and the set charge and discharge thresholds are input into the first monitor and the second monitor to accurately monitor the energy. When the real-time SOC values of the supercapacitor and the lithium battery pack reach the set charge and discharge thresholds, the SOC values of the supercapacitor and the lithium battery pack can be updated in real time, thereby ensuring the life of the supercapacitor and the lithium battery pack and avoiding energy waste.

Refer to FIG. 4 , which is a flow chart of a third embodiment of a composite power system energy management method according to the present invention.

Based on the above first embodiment and second embodiment, step S20 of the composite power system energy management method of this embodiment specifically includes:

Step S201: Compare the acceleration with a preset acceleration threshold value.

It should be noted that the preset acceleration threshold value is the maximum acceleration value set in advance by the staff, such as 0.4gm/s2, 0.8gm/s2, etc. In this embodiment, 0.4gm/s2 is used as an example for explanation. The real-time acceleration of the car is compared with the preset acceleration threshold value, and the power supply management of the motor can be performed accordingly according to the comparison result.

Step S202: When the acceleration is greater than the preset acceleration threshold value, the SOC value of the supercapacitor and/or the SOC value of the lithium battery pack is determined to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter.

It should be understood that when the current acceleration of the car is greater than the preset acceleration threshold value, for example, the current acceleration of the car is 0.5gm/s2, which is greater than the preset acceleration threshold value of 0.4gm/s2, it means that the car is in a rapid acceleration stage and a large amount of electricity needs to be provided to the car. The required power of the vehicle can be provided in three ways: providing the required power of the vehicle according to the SOC value of the supercapacitor, providing the required power of the vehicle according to the SOC value of the supercapacitor and the SOC value of the lithium battery pack, or providing the required power according to the SOC value of the lithium battery pack. The discharge voltage of the supercapacitor is adjusted by the first bidirectional DC/DC converter, and the discharge current of the lithium battery pack is ensured to be stable by the second bidirectional DC/DC converter.

In a specific implementation, if the current acceleration of the vehicle is less than or equal to the preset acceleration threshold value and greater than zero and/or equal to zero, the SOC value of the lithium battery pack is used to provide the required power of the vehicle and the second bidirectional DC/DC converter is used to ensure that the discharge current of the lithium battery pack is stable. This indicates that the vehicle is lightly accelerated at this time, that is, the current acceleration is less than the preset acceleration threshold value and greater than zero, the required power of the vehicle is small, and the lithium battery pack can provide the vehicle's driving power alone. When the current acceleration of the vehicle is zero, it indicates that the vehicle is traveling at a constant speed and does not require a large amount of required power, so the required power for driving can be directly provided by the lithium battery pack alone.

Furthermore, when the current acceleration of the car is less than zero, it means that the car is decelerating or braking. At this time, the car will recover energy and does not need the lithium battery pack or supercapacitor to provide the required power. The recovered energy can be fed back to the supercapacitor first until the current SOC value of the supercapacitor reaches 90% of the charging threshold. If there is still energy to be recovered at this time, it will continue to be fed back to the lithium battery pack to avoid energy waste. Feedback to the supercapacitor first can ensure that when the car needs high-power power supply, there is enough power to meet the needs of the next working condition.

This embodiment compares the acceleration with a preset acceleration threshold value; when the acceleration is greater than the preset acceleration threshold value, the required power of the vehicle is provided according to the SOC value of the supercapacitor and/or the SOC value of the lithium battery pack, and different energy provision methods are performed according to the comparison results of the acceleration with the preset acceleration threshold value, so that energy is reasonably distributed during the use of the supercapacitor and the lithium battery pack, thereby improving energy utilization.

Refer to FIG. 5 , which is a flow chart of a fourth embodiment of a composite power system energy management method according to the present invention.

Based on the above-mentioned first embodiment, second embodiment and third embodiment, step S20 of the composite power system energy management method of this embodiment specifically includes: the charging and discharging thresholds of the supercapacitor include: a first threshold, a second threshold and a third threshold, the first threshold is less than the second threshold, and the second threshold is less than the third threshold; the supercapacitor and/or the lithium battery pack are determined to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, including:

Step S203: When the SOC value of the supercapacitor is greater than the first threshold value and less than the second threshold value, the required power of the vehicle is provided through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, the SOC value of the lithium battery pack and the SOC value of the supercapacitor.

In this embodiment, the first threshold value of the supercapacitor is 0.1, which is 10% of the total power capacity of the supercapacitor battery, the second threshold value of the supercapacitor is 0.6, which is 60% of the total power capacity of the supercapacitor battery, and the third threshold value of the supercapacitor is 1, which means that the total power capacity of the supercapacitor battery is fully charged.

It should be noted that when the SOC value of the supercapacitor is greater than the first threshold value and less than the second threshold value, it means that the SOC value of the supercapacitor is between (0.1, 0.6). At this time, the acceleration of the vehicle is greater than the preset acceleration threshold value, and the car accelerates suddenly. However, the SOC value of the supercapacitor cannot meet the required power of the vehicle motor alone. At this time, the lithium battery pack and the supercapacitor jointly provide the required power for the vehicle to travel. The discharge voltage of the supercapacitor is adjusted by the first bidirectional DC/DC converter, and the discharge current of the lithium battery pack is adjusted by the second bidirectional DC/DC converter.

When the SOC value of the supercapacitor is greater than zero and less than the first threshold, the required power of the vehicle is provided by the second bidirectional DC/DC converter and the SOC value of the lithium battery pack.

It should be understood that when the SOC of the supercapacitor is greater than zero and less than the first threshold, it means that the SOC value of the supercapacitor is between (0,0.1) at this time, and the power of the supercapacitor has reached the minimum discharge threshold and can no longer supply power to the vehicle. The vehicle can be reminded to slow down and charge in time. At this time, the lithium battery pack can provide the required power for the entire vehicle, and the discharge current of the lithium battery pack can be adjusted through the second bidirectional DC/DC converter. The discharge of the lithium battery pack can be monitored in real time through the second monitor. When the SOC value of the lithium battery pack reaches the discharge threshold of the lithium battery pack, the power supply of the lithium battery pack is stopped to avoid affecting the life and recycling of the lithium battery pack.

When the SOC value of the supercapacitor is greater than the second threshold value and less than the third threshold value, the required power of the vehicle is provided by the first bidirectional DC/DC converter and the SOC value of the supercapacitor.

In a specific implementation, when the SOC value of the supercapacitor is greater than the second threshold and less than the third threshold, it means that the SOC value of the supercapacitor is between (0.6, 1) at this time, and the SOC value of the supercapacitor is close to the charging threshold. The supercapacitor can provide the required power for the vehicle alone, and the voltage at the discharge end of the supercapacitor is adjusted through the first bidirectional DC/DC converter. The supercapacitor can discharge high power to the vehicle to meet the acceleration requirements of the vehicle and avoid energy waste.

In this embodiment, the charge and discharge thresholds of the supercapacitor include: a first threshold, a second threshold and a third threshold, the first threshold is less than the second threshold, and the second threshold is less than the third threshold; when the SOC value of the supercapacitor is greater than the first threshold and less than the second threshold, the required power of the vehicle is provided by the SOC value of the lithium battery pack and the SOC value of the supercapacitor, and the real-time SOC value of the supercapacitor is compared with the first threshold, the second threshold and the third threshold, and different charging modes are switched according to the comparison results, thereby achieving maximum utilization of the energy of the composite power supply, avoiding energy waste, and also ensuring the service life and recycling of the lithium battery pack in the composite power supply.

Refer to FIG. 6 , which is a flow chart of a fifth embodiment of a composite power system energy management method according to the present invention.

Based on the first embodiment, the third embodiment and the fourth embodiment, the composite power system energy management method of this embodiment further includes, after step S20:

S24: Monitoring the charging and discharging status of the supercapacitor under the current working condition through the first monitor.

It should be noted that the first monitor is connected in parallel with the supercapacitor to monitor the charging and discharging status and real-time SOC value of the supercapacitor. After the charging and discharging threshold of the supercapacitor is set, the charging and discharging threshold of the supercapacitor is input into the first monitor to monitor the real-time SOC value of the supercapacitor.

S25: Monitoring the charging and discharging status of the lithium battery pack under the current working condition through the second monitor.

It should be understood that the second monitor is connected in parallel with the lithium battery pack to monitor the charge and discharge status and real-time SOC value of the lithium battery pack. After the charge and discharge thresholds of the lithium battery pack are set, the charge and discharge thresholds of the lithium battery pack are input into the second monitor to monitor the real-time SOC value of the lithium battery pack.

S26: When the charge and discharge values of the super capacitor and the lithium battery pack reach the charge and discharge thresholds, the SOC values of the super capacitor and the lithium battery pack are re-input through the first monitor and the second monitor, and the monitoring data are updated in real time.

In a specific implementation, the discharge conditions of the supercapacitor and lithium battery pack under the current working conditions are monitored in real time through the first monitor and the second monitor. When the lithium battery pack discharges at high power for a long time, an early warning can be issued to stop the discharge of the lithium battery to avoid energy waste and affect the cycle life of the lithium battery. When the discharge state of the supercapacitor and lithium battery pack reaches the discharge threshold, the SOC value of the consumed supercapacitor and lithium battery pack can be re-entered and corrected, and the monitoring data can be updated in real time.

In this embodiment, the charge and discharge state of the supercapacitor under the current working condition is monitored by the first monitor; the charge and discharge state of the lithium battery pack under the current working condition is monitored by the second monitor; when the charge and discharge values of the supercapacitor and the lithium battery pack reach the charge and discharge threshold value, the SOC values of the supercapacitor and the lithium battery pack are re-input and the monitoring data is updated in real time through the first monitor and the second monitor, and the energy output during the driving process of the vehicle is accurately monitored through the first monitor and the second monitor, thereby solving the problem that the long-term discharge of the lithium battery in the composite power supply affects the battery cycle service life and the inaccurate display of the power of the composite power supply, thereby improving energy utilization.

It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

In addition, for technical details that are not described in detail in this embodiment, reference can be made to the energy management method for the composite power system provided in any embodiment of the present invention, and will not be repeated here.

In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory (ROM)/RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (1)

1. A composite power system energy management method, wherein the composite power system energy management method is applied to a composite power system, the composite power system comprising: the lithium battery pack comprises a super capacitor, a lithium battery pack, a first bidirectional DC/DC converter, a first monitor, a second monitor and a second bidirectional DC/DC converter;

The first monitor is connected with the super capacitor in parallel, the second monitor is connected with the lithium battery pack in parallel, and the super capacitor and the lithium battery pack are respectively connected with a motor of a vehicle;

the super capacitor is used for providing a power supply to supply power to a motor of the vehicle and filtering current generated in the running process of the automobile;

The lithium battery pack is used for providing a power supply to supply power to a motor of the vehicle;

the first monitor is used for monitoring the real-time SOC value of the super capacitor and updating the real-time SOC value of the super capacitor;

the second monitor is used for monitoring the real-time SOC value of the lithium battery pack and updating the real-time SOC value of the lithium battery pack;

The first end of the first bidirectional DC/DC converter is connected with the super capacitor, the second end of the first bidirectional DC/DC converter is connected with the motor of the vehicle, the first end of the second bidirectional DC/DC converter is connected with the lithium battery pack, and the second end of the bidirectional DC/DC converter is connected with the motor of the vehicle;

the first bidirectional DC/DC converter is used for adjusting the charge and discharge voltages of the super capacitor;

The second bidirectional DC/DC converter is used for decoupling the lithium battery pack, so that the lithium battery pack is prevented from being influenced by peak power, and the charging and discharging currents of the lithium battery pack are ensured to be stable;

the method comprises the following steps:

Acquiring acceleration of the automobile under the current working condition;

Determining that the super capacitor and/or the lithium battery pack provide the required power of the vehicle according to the acceleration through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter;

before determining that the super capacitor and/or the lithium battery pack provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, the method further comprises:

Collecting basic parameter information of the super capacitor and the lithium battery pack, wherein the basic parameter information comprises at least one of electromotive force, rated capacity, rated voltage, open-circuit voltage, internal resistance, charge-discharge rate, impedance, service life and self-discharge rate of the super capacitor and the lithium battery pack;

setting a charge-discharge threshold of the super capacitor and the lithium battery pack based on the basic parameter information;

Acquiring the SOC value of the super capacitor and the lithium battery pack;

The determining, according to the acceleration, the super capacitor and/or the lithium battery pack to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, including:

comparing the acceleration with a preset acceleration threshold value;

When the acceleration is larger than the preset acceleration threshold value, determining an SOC value of the super capacitor and/or an SOC value of the lithium battery pack to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter;

The charge and discharge threshold of the super capacitor comprises the following steps: a first threshold, a second threshold, and a third threshold, the first threshold being less than the second threshold, the second threshold being less than the third threshold;

The determining, according to the acceleration, the super capacitor and/or the lithium battery pack to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, including:

when the SOC value of the super capacitor is larger than the first threshold value and smaller than the second threshold value, providing the required power of the vehicle through the SOC values of the first bidirectional DC/DC converter, the second bidirectional DC/DC converter, the lithium battery pack and the super capacitor;

The determining, according to the acceleration, the super capacitor and/or the lithium battery pack to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, including:

When the SOC value of the super capacitor is larger than zero and smaller than the first threshold value, providing the required power of the vehicle through the second bidirectional DC/DC converter and the SOC value of the lithium battery pack;

The determining, according to the acceleration, the super capacitor and/or the lithium battery pack to provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter, including:

Providing the required power of the vehicle through the first bidirectional DC/DC converter and the SOC value of the super capacitor when the SOC value of the super capacitor is larger than the second threshold value and smaller than the third threshold value;

after determining that the super capacitor and/or the lithium battery pack provide the required power of the vehicle through the first bidirectional DC/DC converter and/or the second bidirectional DC/DC converter according to the acceleration, the method further comprises the following steps:

monitoring the charge and discharge states of the super capacitor under the current working condition through the first monitor;

monitoring the charge and discharge states of the lithium battery pack under the current working condition through the second monitor;

when the charge and discharge values of the super capacitor and the lithium battery pack reach a charge and discharge threshold, the SOC values of the super capacitor and the lithium battery pack are input again through the first monitor and the second monitor, and monitoring data are updated in real time;

after comparing the acceleration with a preset acceleration threshold value, the method further comprises:

Providing the required power of the vehicle through the second bidirectional DC/DC converter and the SOC value of the lithium battery pack when the acceleration is smaller than or equal to the preset acceleration threshold value and larger than zero and/or equal to zero;

And when the discharge states of the super capacitor and the lithium battery pack reach the discharge threshold, re-inputting and correcting the consumed SOC values of the super capacitor and the lithium battery pack, and updating the monitoring data in real time.