CN113071369B - Current protection-based method, control system and electric automobile - Google Patents
Current protection-based method, control system and electric automobile Download PDFInfo
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- CN113071369B CN113071369B CN202110343798.XA CN202110343798A CN113071369B CN 113071369 B CN113071369 B CN 113071369B CN 202110343798 A CN202110343798 A CN 202110343798A CN 113071369 B CN113071369 B CN 113071369B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
- B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
- B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
- B60R16/023—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for transmission of signals between vehicle parts or subsystems
- B60R16/0231—Circuits relating to the driving or the functioning of the vehicle
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Abstract
The invention provides a current protection-based method, a control system and an electric vehicle, and relates to the technical field of electric vehicles, wherein the method comprises the following steps: the battery management system controls the state of the main contactor according to the magnitude relation between the current and the two preset currents, meanwhile, the vehicle control unit calculates according to the received actual operation parameters to obtain the current actual power of the power battery management system, and then controls the state of the main contactor based on the current actual power of the power battery management system and the duration of keeping the current actual power. In addition, the fuse can trigger active fusing when the current is too large, and the function of protecting the main loop of the power battery is achieved. The invention realizes the accurate protection of the whole vehicle current universe, avoids the overheating and burning of parts, circuits and the like of the electric vehicle, avoids the electric shock of personnel and the personal safety of crisis, and has higher practicability.
Description
Technical Field
The invention relates to the technical field of electric vehicles, in particular to a current protection-based method and device and an electric vehicle.
Background
In the electric automobile on the market at present, the main loop of the power battery is connected in series with a safety device. The function of the safety device is to ensure that the main loop of the power battery can be disconnected in time in abnormal conditions so as to achieve the aim of protecting personnel and vehicles safely.
However, in the normal operation process of the conventional electric automobile, because the current interval of the whole automobile is wide, the current global protection is difficult to realize only by using insurance.
Disclosure of Invention
In view of the above, the present invention has been made to provide a method, a device and an electric vehicle based on current protection that overcome or at least partially solve the above problems.
In a first aspect, a method based on current protection is provided, and the method is applied to a control system, and the control system comprises: the battery management system and the vehicle control unit, the method comprises the following steps:
the battery management system determines the magnitude relation between the current and a first preset current and a second preset current;
the battery management system executes an overrun power logic operation under the condition that the current is not larger than the first preset current;
the battery management system controls the state of the main contactor according to the result of the over-limit power logic operation;
the battery management system controls the state of the main contactor according to the size relation between the duration time of the current and a first preset duration when the current is larger than the first preset current and smaller than the second preset current;
under the condition that the current is not less than the second preset current, the battery management system controls the state of the main contactor according to the size relation between the duration of the current and the first preset duration by combining the type selection of a fuse or triggers the fuse to be actively fused;
the vehicle control unit obtains the current actual power of the power battery management system according to actual operation parameters, wherein the actual operation parameters come from the power battery management system;
and the vehicle control unit controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
Optionally, in a case that the present current is not greater than the first preset current, performing an overrun power logic operation, including:
determining the magnitude relation between the current actual load power of the whole vehicle and the highest allowable power of a power battery management system, and determining the magnitude relation between the duration of the current actual load power of the whole vehicle and a second preset duration maintained by the load power.
Optionally, controlling the state of the main contactor according to the result of the power-overrun logic operation includes:
under the condition that the current actual load of the whole vehicle is larger than the highest allowable power of the power battery management system, and the duration of the load power maintaining the current actual load power of the whole vehicle is not smaller than the second preset duration, controlling the main contactor to be switched off;
the current actual load power of the whole vehicle is not more than the highest allowable power of the power battery management system, or the current actual load power of the whole vehicle is more than the highest allowable power of the power battery management system, and the load power is maintained, the duration of the current actual load power of the whole vehicle is less than the second preset duration, and the main contactor is controlled to be kept closed.
Optionally, when the present current is greater than the first preset current and less than the second preset current, controlling the state of the main contactor according to a size relationship between a duration of the present current and a first preset duration, including:
under the condition that the duration time of the current is not less than the first preset time, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, under the condition that the current is not less than the second preset current, controlling the state of the main contactor according to a size relationship between a duration of the current and the first preset duration in combination with a type selection of an insurance, or triggering the insurance to actively fuse, includes:
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is equal to the second preset current, any one of the following processing modes is included: controlling the main contactor to be disconnected, and triggering the fuse to be actively fused;
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is greater than the second preset current, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, the first preset current is a maximum design current of the whole vehicle;
the second preset current is determined based on a fusing current operation of the fuse.
Optionally, the vehicle controller controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system maintaining the current actual power, including:
the vehicle control unit determines the size relationship between the current actual power of the power battery management system and the maximum allowable power of the whole vehicle, and determines the size relationship between the duration of the current actual power kept by the power battery management system and a third preset duration;
the vehicle controller controls the main contactor to be disconnected under the condition that the current actual power of the power battery management system is larger than the maximum allowable power of the whole vehicle and the duration of the current actual power kept by the power battery management system is not smaller than the third preset duration;
and the vehicle controller controls the main contactor to be closed under the condition that the current actual power of the power battery management system is not larger than the maximum allowable power of the whole vehicle, or the current actual power of the power battery management system is larger than the maximum allowable power of the whole vehicle, and the duration of the current actual power kept by the power battery management system is smaller than the third preset duration.
Optionally, the obtaining, by the vehicle controller, the current actual power of the power battery management system according to the actual operating parameter includes:
the vehicle control unit receives the actual operation parameters, and the actual operation parameters comprise: actual operating current and actual operating voltage;
and the vehicle control unit calculates to obtain the current actual power of the power battery management system according to the actual operation current and the actual operation voltage.
In a second aspect, there is also provided a control system based on current protection, the control system comprising: battery management system, vehicle control unit, battery management system includes:
the current magnitude relation determining module is used for determining the magnitude relation between the current and the first preset current and the second preset current;
the execution logic operation module is used for executing the overrun power logic operation under the condition that the current is not larger than the first preset current;
the first control state module is used for controlling the state of the main contactor according to the result of the over-limit power logic operation;
the second control state module is used for controlling the state of the main contactor according to the magnitude relation between the duration time of the current and the first preset duration time under the condition that the current is greater than the first preset current and smaller than the second preset current;
the third control state module is used for controlling the state of the main contactor or triggering the fuse to be actively fused according to the size relation between the duration time of the current and the first preset time length and in combination with the type selection of the fuse under the condition that the current is not less than the second preset current;
the vehicle control unit comprises:
the actual power module is used for obtaining the current actual power of the power battery management system according to actual operation parameters, and the actual operation parameters are from the power battery management system;
and the decision control module is used for controlling the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
Optionally, the execution logic operation module is specifically configured to:
determining the magnitude relation between the current actual load power of the whole vehicle and the highest allowable power of a power battery management system, and determining the magnitude relation between the duration of the current actual load power of the whole vehicle and a second preset duration maintained by the load power.
Optionally, the first control state module is specifically configured to:
under the condition that the current actual load power of the whole vehicle is greater than the highest allowable power of the power battery management system, and the duration of the load power maintaining the current actual load power of the whole vehicle is not less than the second preset duration, controlling the main contactor to be switched off;
the current actual load power of the whole vehicle is not more than the highest allowable power of the power battery management system, or the current actual load power of the whole vehicle is more than the highest allowable power of the power battery management system, and the load power is maintained, the duration of the current actual load power of the whole vehicle is less than the second preset duration, and the main contactor is controlled to be kept closed.
Optionally, the second control state module is specifically configured to:
under the condition that the duration time of the current is not less than the first preset time, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, the third control state module is specifically configured to:
when the duration of the current is not less than the first preset duration and the fuse current lower limit value of the fuse is equal to the second preset current, any one of the following processing modes is included: controlling the main contactor to be disconnected, and triggering the fuse to be actively fused;
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is greater than the second preset current, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, the decision control module includes:
the size relation determining unit is used for determining the size relation between the current actual power of the power battery management system and the maximum allowable power of the whole vehicle, and determining the size relation between the duration time of the current actual power kept by the power battery management system and a third preset time;
the control disconnection unit is used for controlling the main contactor to be disconnected under the condition that the current actual power of the power battery management system is larger than the highest allowable power of the whole vehicle, and the duration of the current actual power of the power battery management system is not smaller than the third preset duration;
and the closing keeping unit is used for keeping the current actual power of the power battery management system not larger than the highest allowable power of the whole vehicle, or keeping the current actual power of the power battery management system larger than the highest allowable power of the whole vehicle, and controlling the main contactor to be closed under the condition that the duration of the current actual power kept by the power battery management system is smaller than the third preset duration.
Optionally, the actual power module comprises:
a receiving unit, configured to receive the actual operation parameter, where the actual operation parameter includes: an actual operating current and an actual operating voltage;
and the operation unit is used for obtaining the current actual power of the power battery management system through operation according to the actual operation current and the actual operation voltage.
In a third aspect, an electric vehicle is provided, which includes: a control system;
the control system is configured to perform the method of any one of the first aspects;
the embodiment of the application has the following advantages:
in the invention, the battery management system firstly determines the magnitude relation between the current and the first preset current and the second preset current, and controls the state of the main contactor according to the magnitude relation. Executing the over-limit power logic operation under the condition that the current is not greater than a first preset current; controlling the state of the main contactor according to the result of the over-limit power logic operation; under the condition that the current is greater than a first preset current and less than a second preset current, controlling the state of the main contactor according to the size relation between the duration of the current and a first preset time length; and under the condition that the current is not less than the second preset current, controlling the state of the main contactor or triggering the fuse to be actively fused according to the size relation between the duration of the current and the first preset time length and by combining the type selection of the fuse. When the battery management system carries out the method, the vehicle control unit obtains the current actual power of the power battery management system according to the actual operation parameters from the power battery management system, and then controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the current actual power kept by the power battery management system.
The invention changes the control strategy of the main contactor without changing the existing circuit structure, and realizes the accurate protection of the whole vehicle current universe by matching with the existing insurance. Therefore, the main loop of the power battery is disconnected in time through the main contactor or the fuse under abnormal conditions, so that the effect of protecting personnel and vehicles is achieved, and the practicability is high.
Drawings
Various additional advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a schematic diagram schematically illustrating a main loop circuit structure of a current power battery;
FIG. 2 is a flow chart of a method for current based protection according to an embodiment of the present invention;
fig. 3 is a block diagram of a current protection based device according to an embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention, are only a few examples of the invention, are not intended to limit the invention.
The inventor finds that in the normal operation process of the conventional electric automobile, only the insurance of a main loop of a power battery is used to hardly realize the current global protection due to the wider current interval of the whole automobile. The inventor further researches and discovers that the main reason causing the problem is the difference of the current of the whole vehicle under different abnormal conditions, specifically:
referring to fig. 1, a schematic diagram of a main loop circuit structure of a present power battery is exemplarily shown, where fig. 1 includes: the system comprises a fuse F1, a power Battery Battery, a main contactor S1 (comprising a discharging positive contactor S1+ and a discharging negative contactor S1-), a capacitor C1, a capacitor C2, a front motor control bridge arm circuit (a dotted frame 10 in the figure 1), a rear motor control bridge arm circuit (a dotted frame 20 in the figure 1), a front motor M1 and a rear motor M2.
Therefore, the fuse F1 needs to be automatically fused when a circuit short circuit occurs, so as to protect the power battery main loop from being disconnected in time. However, in the actual working process, the current interval of the whole vehicle is wide, and when any part has a short-circuit fault, the short-circuit current is different due to different short-circuit resistances when a short circuit occurs. For a smaller short-circuit resistor, the short-circuit current is larger, and the fuse can be timely fused under the condition that the short-circuit current exceeds the fusing current of the fuse. However, for a larger short-circuit resistor, the short-circuit current is smaller, and the fuse may not be blown when the fuse blowing current is not reached. The main loop of the power battery is still conducted, and the short-circuit current exists continuously, so that not only parts, circuits and the like of the electric automobile are burnt due to overheating, but also personnel are electrically shocked, and the personal safety is endangered.
Based on the above problems, the inventors have made extensive studies, tests and simulations, and have creatively proposed the current protection-based method of the present invention, which will be described in detail below.
Referring to fig. 2, a flow chart of a method based on current protection according to an embodiment of the present invention is shown, the method is applied to a control system, and the control system includes: the battery management system and the vehicle control unit comprise the following steps:
step 101: the battery management system determines the magnitude relation between the current and the first preset current and the second preset current.
In the embodiment of the invention, in the running process of the electric automobile, the current of the whole automobile can be determined by a Battery Management System (BMS), and then the magnitude relation between the current of the whole automobile and the first preset current and the second preset current is determined.
In the embodiment of the invention, the running safety of the electric automobile is comprehensively considered, and the first preset current is set as the maximum design current of the whole automobile; the so-called maximum design current of the whole vehicle can be calculated according to the known method. And the second predetermined current is determined based on the fuse blowing current operation of the fuse. Generally, the fuse has a characteristic that the fuse has a larger current and a shorter operation time period because the fuse has a characteristic that the fuse is selected according to an inverse time curve, that is, a square of the current and a time curve, and thus the fuse can be considered to have an interval value. And integrating the fusing current and the time factor of the fuse to calculate and determine a second preset current. For example: and determining a second preset current based on the fusing current corresponding to the 2-second time period.
In the embodiment of the invention, for realizing the whole vehicle current global protection, the state of the main contactor or the fuse is determined according to the magnitude relation between the current of different whole vehicles and the first preset current and the second preset current.
Step 102: and the battery management system executes the over-limit power logic operation under the condition that the current is not greater than the first preset current.
In the embodiment of the invention, the maximum design current of the whole automobile determined in the design of the electric automobile is a classical value, and in the actual operation process of the electric automobile, the actual current of the whole automobile should not reach or even exceed the maximum design current of the whole automobile. Therefore, the BMS performs the over-limit power logic operation in the case that the present current is not greater than the first preset current. The reason why the over-limit power logic operation is performed is that even if the current is not greater than the first preset current, if the current is higher and is very close to the first preset current, if the current is in the operating state for a long time, there is a higher probability that an abnormal condition occurs, such as a circuit damage caused by heating of the current, or the current is higher and exceeds the allowable upper limit value of some parts. It is therefore necessary to protect the current in time when such a situation occurs.
The specific method for executing the overrun power logic operation comprises the following steps: and the BMS determines the magnitude relation between the current actual load power of the whole vehicle and the maximum allowable power of the BMS, and determines the magnitude relation between the duration of the current actual load power of the whole vehicle maintained by the load power and a second preset duration.
Due to the characteristics of the power battery, the power battery has a rated operation power, the more the power battery exceeds the rated operation power, and the longer the duration, the more the damage to the power battery is, the overheating of a line or the exceeding of the allowable current of parts can occur. Therefore, in the embodiment of the present invention, 120% of the rated operating power of the power battery is regarded as the maximum allowed power of the BMS, and it is considered that the maximum allowed power of the BMS is exceeded, and the duration of the maximum allowed power of the BMS is exceeded for a certain period of time, which may cause great damage to the power battery, and the probability of overheating a line or exceeding the allowable current of a component is high. Therefore, the relationship between the current actual load power of the whole vehicle and the maximum allowed power of the BMS needs to be determined, and the relationship between the duration of the load power maintaining the current actual load power of the whole vehicle and the second preset duration needs to be determined.
Step 103: and the battery management system controls the state of the main contactor according to the result of the over-limit power logic operation.
In the embodiment of the invention, the BMS determines the relationship between the current actual load power of the whole vehicle and the maximum allowable power of the BMS, and controls the state of the main contactor according to the result of the logic operation of the overrun power after determining the relationship between the duration of the current actual load power of the whole vehicle maintained by the load power and the second preset duration.
Specifically, the BMS controls the main contactor to be disconnected under the condition that the current actual load power of the whole vehicle is greater than the maximum allowable power of the BMS and the duration of the current actual load power of the whole vehicle is not less than the second preset duration. The second preset time period may be 5 seconds, which is an empirical value obtained through a large number of operations and actual measurement. Namely, under the condition that the current actual load power of the whole vehicle is greater than 120% of the rated operation power of the power battery and the duration of the load power maintaining the current actual load power of the whole vehicle is not less than 5 seconds, the BMS controls the main contactor to be switched off, so that the damage to the power battery is avoided, and the condition that the line is overheated or the allowable current of parts is not exceeded is avoided.
And the BMS controls the main contactor to be still closed under the condition that the current actual load power of the whole vehicle is not more than the maximum allowable power of the BMS, or the current actual load power of the whole vehicle is more than the maximum allowable power of the power battery management system, and the duration of the current actual load power of the whole vehicle maintained by the load power is less than a second preset duration. Namely, when the current actual load power of the whole vehicle is not more than 120% of the rated operation power of the power battery, or when the current actual load power of the whole vehicle is more than 120% of the rated operation power of the power battery and the duration of the load power maintaining the current actual load power of the whole vehicle is less than 5 seconds, the BMS controls the main contactor to be still kept closed, and because the operating state does not cause damage to the power battery, the situation that a line is overheated or the allowable current of parts is not exceeded is avoided.
Step 104: and when the current is greater than the first preset current and less than the second preset current, the battery management system controls the state of the main contactor according to the size relation between the duration of the current and the first preset duration.
In the embodiment of the invention, in the actual running process of the electric automobile, if the actual current of the whole automobile exceeds the maximum design current of the whole automobile, which is an unallowable condition, the problem that the current is heated to cause circuit damage or exceed the allowable upper limit value of certain parts can certainly occur, so that the safety of the whole automobile is endangered, and the safety of personnel is also endangered. However, if the actual current of the whole vehicle exceeds the maximum design current of the whole vehicle, only a very short time is allowed, so that the BMS controls the state of the main contactor according to the magnitude relation between the duration of the current and the first preset duration under the condition that the current is greater than the first preset current and less than the second preset current. Specifically, the method comprises the following steps:
the BMS controls the main contactor to be disconnected under the condition that the duration of the current is not less than a first preset duration; and controlling the main contactor to be kept closed under the condition that the duration of the current is less than a first preset time. The first preset time is 2 seconds, which is also an empirical value obtained through a large number of calculations and actual measurements. Namely, under the condition that the current is greater than the first preset current and less than the second preset current, if the duration time of the current of the BMS is not less than 2 seconds, the BMS controls the main contactor to be switched off; and controlling the main contactor to continuously keep closed when the duration of the current is less than 2 seconds.
Step 105: and under the condition that the current is not less than the second preset current, the battery management system controls the state of the main contactor or triggers the fuse to be actively fused according to the size relation between the duration of the current and the first preset duration by combining the selection of the fuse.
In the embodiment of the invention, as described above, the second predetermined current is determined based on the fuse blowing current operation of the fuse. If the current exceeds the second preset current, the safety problem of the electric automobile and personnel can be caused, however, if the current appears in a very short time, the safety problem can be allowed, and because the fusing current of the fuse is an interval value, the lower limit value of the fusing current of the fuse can be equal to or higher than the second preset current. The lower limit of the fusing current of the fuse is generally not less than the second preset current value, so the following conditions are present:
1) And when the duration of the current of the BMS is not less than a first preset duration and the lower limit value of the fuse current of the BMS is equal to a second preset current, the BMS comprises any one of the following processing modes: and controlling the main contactor to be disconnected, and triggering the fuse to be actively fused. The fuse is a limit condition, because the lower limit value of the fusing current of the fuse is equal to the second preset current, and the duration of the current is not less than the first preset time, the BMS may control the main contactor to be disconnected first, so that the main loop of the power battery is disconnected, and the fuse cannot be actively fused; however, it is also possible that the fuse is first fused, and then the main circuit of the power battery is also disconnected, and in general, after the main circuit of the power battery is disconnected, the BMS controls the main contactor to be disconnected according to the characteristics of the main contactor and the operation principle of the main circuit of the power battery. That is, in the case that the fuse current lower limit value of the fuse is equal to the second preset current, either the BMS controls the main contactor to be turned off first, or the fuse triggers active fuse in advance.
2) And the BMS controls the main contactor to be disconnected under the conditions that the duration time of the current is not less than a first preset duration and the lower limit value of the fusing current of the fuse is greater than a second preset current. It can be understood that if the fusing current lower limit value of the fuse is greater than the second preset current, the BMS controls the main contactor to be opened first, and the fuse cannot be fused. However, if the current suddenly rises to exceed the fuse-out lower current limit of the fuse and the duration is not less than the first preset time, the same situation as that of the point 1) can occur, and either the BMS controls the main contactor to be turned off first or the fuse triggers active fuse-out in advance.
3) And the BMS controls the main contactor to be closed under the condition that the duration of the current is less than a first preset duration. This kind of condition is exactly that the current appears the condition that the second is predetermine current that extremely short, and then the insurance can not be fused, and BMS control main contactor is according to keeping closing.
In addition, in the embodiment of the present invention, considering that a Vehicle Control Unit (VCU) has a stronger operation processing capability and can receive various operating state parameters of a vehicle, while the BMS executes the method of the above step 101 to step 105, the VCU can also control the state of the main contactor, thereby better playing a role in protecting the safety of the electric vehicle, specifically:
step 201: and the vehicle control unit obtains the current actual power of the power battery management system according to the actual operation parameters, wherein the actual operation parameters come from the power battery management system.
In general, the VCU may receive actual operation parameters output by the power battery during actual operation, which are sent from the BMS, and the actual operation parameters include, but are not limited to: actual operating current, actual operating voltage, actual operating temperature, and the like.
Specifically, after the VCU receives the actual operation current and the actual operation voltage, the actual power of the BMS can be obtained through calculation according to the actual operation current and the actual operation voltage.
Because the VCU has stronger operation processing capacity, the VCU can calculate the current actual power of the power battery according to the actual operation current and the actual operation voltage output by the power battery, and the current actual power is taken as the current actual power of the BMS.
Step 202: and the vehicle control unit controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
After the VCU obtains the current actual power of the BMS, the state of the main contactor can be controlled according to the current actual power of the BMS and the duration of the BMS for keeping the current actual power.
Specifically, the method comprises the following steps:
step S1: and the VCU determines the size relation between the current actual power of the BMS and the maximum allowable power of the whole vehicle, and determines the size relation between the duration of the current actual power kept by the BMS and a third preset duration.
Step S2: and the VCU controls the main contactor to be switched off under the conditions that the current actual power of the BMS is larger than the maximum allowable power of the whole vehicle and the duration of the BMS for keeping the current actual power is not smaller than a third preset duration.
The VCU obtains the current actual power of the BMS according to step 201. The maximum allowable power of the entire vehicle can be calculated according to the sum of the rated power of the driving motor and the power of each component, generally, it is considered that the maximum allowable power of the entire vehicle = (the rated power of the driving motor + the power of each component) × 120%, the third preset time period can be 10 seconds, and the third preset time period is also an empirical value obtained according to a large number of calculations and actual measurements. That is, the VCU controls the main contactor to be turned off when the current actual power of the BMS is greater than (rated power of the driving motor + power of each component) × 120%, and the BMS maintains the current actual power for not less than 10 seconds. Therefore, the power battery is protected from being damaged, and the situation that the circuit is overheated or the allowable current of parts is exceeded is avoided.
And step S3: and the VCU controls the main contactor to be closed under the condition that the current actual power of the BMS is not more than the maximum allowable power of the whole vehicle, or the current actual power of the BMS is more than the maximum allowable power of the whole vehicle and the duration of the current actual power of the BMS is less than a third preset duration.
That is, the VCU controls the main contactor to remain closed in a case where the current actual power of the BMS is not more than (rated power of the driving motor + power of each component) × 120%, or the current actual power of the BMS is more than (rated power of the driving motor + power of each component) × 120%, and the duration in which the BMS maintains the current actual power is less than 10 seconds. In this operating state, no damage is caused to the power battery, and no overheating of the lines or exceeding of the allowable current of the components occurs.
In the above process, while the BMS executes the methods of steps 101 to 105, the VCU continuously receives the actual operating parameters from the BMS, calculates the current actual power of the BMS, and controls the state of the main contactor according to the method of step 202. However, since the VCU receives data transmitted from the BMS and performs an operation according to its own software algorithm, it delays the control of the main contactor to some extent. If the current of the whole vehicle is large, for example, the current is already larger than the first preset current, the BMS actually controls the state of the main contactor according to the methods in steps 103 to 105, or the fuse may be blown in advance, so the method executed by the VCU is substantially suitable for the case that the current is not larger than the first preset current, or the main contactor cannot be controlled due to a failure caused by other factors of the BMS, and the VCU can control the main contactor under the case that the fuse is not blown in time due to other factors, thereby reliably ensuring the safety of the electric vehicle.
Based on the method based on current protection, an embodiment of the present invention further provides a control system based on current protection, and referring to fig. 3, a schematic structural diagram of the control system based on current protection according to the embodiment of the present invention is shown, where the control system includes: battery management system, vehicle control unit, battery management system includes:
the current magnitude relation determining module is used for determining the magnitude relation between the current and the first preset current and the second preset current;
the execution logic operation module is used for executing the over-limit power logic operation under the condition that the current is not greater than the first preset current;
the first control state module is used for controlling the state of the main contactor according to the result of the over-limit power logic operation;
the second control state module is used for controlling the state of the main contactor according to the magnitude relation between the duration time of the current and the first preset duration time under the condition that the current is greater than the first preset current and smaller than the second preset current;
the third control state module is used for controlling the state of the main contactor or triggering the fuse to be actively fused according to the size relation between the duration time of the current and the first preset time length and in combination with the type selection of the fuse under the condition that the current is not less than the second preset current;
the vehicle control unit comprises:
the actual power module is used for obtaining the current actual power of the power battery management system according to actual operation parameters, and the actual operation parameters come from the power battery management system;
and the decision control module is used for controlling the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
Optionally, the execution logic operation module is specifically configured to:
determining the magnitude relation between the current actual load power of the whole vehicle and the highest allowable power of a power battery management system, and determining the magnitude relation between the duration of the current actual load power of the whole vehicle and a second preset duration maintained by the load power.
Optionally, the first control state module is specifically configured to:
under the condition that the current actual load power of the whole vehicle is greater than the highest allowable power of the power battery management system, and the duration of the load power maintaining the current actual load power of the whole vehicle is not less than the second preset duration, controlling the main contactor to be switched off;
and controlling the main contactor to be kept closed under the condition that the current actual load power of the whole vehicle is not more than the highest allowable power of the power battery management system, or the current actual load power of the whole vehicle is more than the highest allowable power of the power battery management system, and the load power is maintained under the condition that the duration of the current actual load power of the whole vehicle is less than the second preset duration.
Optionally, the second control state module is specifically configured to:
under the condition that the duration time of the current is not less than the first preset time, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, the third control state module is specifically configured to:
when the duration of the current is not less than the first preset duration and the fuse current lower limit value of the fuse is equal to the second preset current, any one of the following processing modes is included: controlling the main contactor to be disconnected, and triggering the fuse to be actively fused;
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is greater than the second preset current, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
Optionally, the decision control module comprises:
the size relation determining unit is used for determining the size relation between the current actual power of the power battery management system and the maximum allowable power of the whole vehicle and determining the size relation between the duration time of the current actual power kept by the power battery management system and a third preset time;
the control disconnection unit is used for controlling the main contactor to be disconnected under the condition that the current actual power of the power battery management system is larger than the maximum allowable power of the whole vehicle and the duration of the current actual power of the power battery management system is not smaller than the third preset duration;
and the closing keeping unit is used for keeping the current actual power of the power battery management system not larger than the highest allowable power of the whole vehicle, or keeping the current actual power of the power battery management system larger than the highest allowable power of the whole vehicle, and controlling the main contactor to be closed under the condition that the duration of the current actual power kept by the power battery management system is smaller than the third preset duration.
Optionally, the actual power module comprises:
a receiving unit, configured to receive the actual operation parameter, where the actual operation parameter includes: actual operating current and actual operating voltage;
and the operation unit is used for obtaining the current actual power of the power battery management system through operation according to the actual operation current and the actual operation voltage.
Based on the above method based on current protection, an embodiment of the present invention further provides an electric vehicle, where the electric vehicle includes: a control system;
the control system is configured to perform the method according to any one of the steps 101 to 105, and the steps 201 to 202.
Through the embodiment, under the condition that the current is not greater than the first preset current, the BMS determines the magnitude relation between the current actual load power of the whole vehicle and the maximum allowable power of the BMS, and determines the magnitude relation between the duration time for maintaining the current actual load power of the whole vehicle and the second preset time; under the conditions that the current actual load power of the whole vehicle is greater than the maximum allowable power of the BMS and the duration of the load power maintaining the current actual load power of the whole vehicle is not less than a second preset duration, the BMS controls the main contactor to be disconnected; and when the current actual load power of the whole vehicle is not more than the highest allowable power of the BMS, or the current actual load power of the whole vehicle is more than the highest allowable power of the power battery management system, and the duration of the current actual load power of the whole vehicle maintained by the load power is less than a second preset duration, the BMS controls the main contactor to be still kept closed. Under the condition that the current is greater than a first preset current and less than a second preset current, the duration time of the current is not less than a first preset duration, and the BMS controls the main contactor to be switched off; and if the duration of the current is less than a first preset duration, the BMS controls the main contactor to be closed. And under the condition that the current is not less than the second preset current, controlling the state of the main contactor or triggering the fuse to be actively fused according to the size relation between the duration of the current and the first preset time length and by combining the type selection of the fuse. Meanwhile, the VCU obtains the current actual power of the BMS according to the actual operation parameters from the BMS, and controls the state of the main contactor according to the current actual power of the BMS and the duration of the current actual power kept by the BMS.
The invention changes the control strategy of the main contactor without changing the existing circuit structure, and realizes the accurate protection of the whole vehicle current universe by matching with the existing insurance. Therefore, the main circuit of the power battery is disconnected in time through the main contactor or the fuse under abnormal conditions, overheating burnout of parts, circuits and the like of the electric automobile is avoided, electric shock of personnel is avoided, personal safety of the crisis is guaranteed, and the practicability is high.
While preferred embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or terminal apparatus that comprises the element.
The technical solutions provided by the embodiments of the present invention are described in detail above, and the principles and embodiments of the present invention are explained herein by using specific examples, and the descriptions of the above embodiments are only used to help understanding the method and the core ideas of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (9)
1. A method based on current protection is characterized in that the method is applied to a control system, and the control system comprises: the power battery management system and the vehicle control unit, the method comprises the following steps:
the power battery management system determines the magnitude relation between the current and a first preset current and a second preset current;
the power battery management system executes an overrun power logic operation under the condition that the current is not greater than the first preset current, and executes an overrun power logic operation under the condition that the current is not greater than the first preset current, including: determining the magnitude relation between the current actual load power of the whole vehicle and the highest allowable power of a power battery management system, and determining the magnitude relation between the duration of the current actual load power of the whole vehicle maintained by the load power and a second preset duration;
the power battery management system controls the state of the main contactor according to the result of the over-limit power logic operation;
the power battery management system controls the state of the main contactor according to the magnitude relation between the duration time of the current and a first preset duration when the current is larger than the first preset current and smaller than the second preset current;
under the condition that the current is not less than the second preset current, the power battery management system controls the state of the main contactor according to the size relation between the duration of the current and the first preset duration by combining the type selection of a fuse or triggers the fuse to be actively fused;
the vehicle control unit obtains the current actual power of the power battery management system according to actual operation parameters, wherein the actual operation parameters come from the power battery management system;
and the vehicle control unit controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
2. The method of claim 1, wherein controlling the state of the main contactor according to the result of the over-limit power logic operation comprises:
under the condition that the current actual load power of the whole vehicle is greater than the highest allowable power of the power battery management system, and the duration of the load power maintaining the current actual load power of the whole vehicle is not less than the second preset duration, controlling the main contactor to be switched off;
the current actual load power of the whole vehicle is not more than the highest allowable power of the power battery management system, or the current actual load power of the whole vehicle is more than the highest allowable power of the power battery management system, and the load power is maintained, the duration of the current actual load power of the whole vehicle is less than the second preset duration, and the main contactor is controlled to be kept closed.
3. The method according to claim 1, wherein in the case that the present current is greater than the first preset current and less than the second preset current, controlling the state of the main contactor according to a magnitude relationship between a duration of the present current and a first preset duration comprises:
under the condition that the duration time of the current is not less than the first preset time, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
4. The method according to claim 1, wherein in a case that the present current is not less than the second preset current, controlling a state of the main contactor according to a size relationship between a duration of the present current and the first preset time duration in combination with a type selection of an insurance, or triggering the insurance to actively blow, includes:
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is equal to the second preset current, any one of the following processing modes is included: controlling the main contactor to be disconnected, and triggering the fuse to be actively fused;
when the duration of the current is not less than the first preset duration and the fusing current lower limit value of the fuse is greater than the second preset current, controlling the main contactor to be switched off;
and controlling the main contactor to be closed under the condition that the duration of the current is less than the first preset time.
5. The method of claim 1, wherein the first predetermined current is a full vehicle maximum design current;
the second preset current is determined based on a fusing current operation of the fuse.
6. The method according to claim 1, wherein the vehicle control unit controls the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system maintaining the current actual power, and comprises:
the vehicle control unit determines the size relationship between the current actual power of the power battery management system and the maximum allowable power of the whole vehicle, and determines the size relationship between the duration of the current actual power kept by the power battery management system and a third preset duration;
the vehicle controller controls the main contactor to be disconnected under the condition that the current actual power of the power battery management system is larger than the maximum allowable power of the whole vehicle and the duration of the current actual power kept by the power battery management system is not smaller than the third preset duration;
and the vehicle controller controls the main contactor to be closed under the condition that the current actual power of the power battery management system is not larger than the maximum allowable power of the whole vehicle, or the current actual power of the power battery management system is larger than the maximum allowable power of the whole vehicle, and the duration of the current actual power kept by the power battery management system is smaller than the third preset duration.
7. The method according to claim 1, wherein the vehicle control unit obtains the current actual power of the power battery management system according to actual operating parameters, and the method comprises the following steps:
the vehicle control unit receives the actual operation parameters, and the actual operation parameters comprise: an actual operating current and an actual operating voltage;
and the vehicle control unit calculates to obtain the current actual power of the power battery management system according to the actual operation current and the actual operation voltage.
8. A control system based on current protection, the control system comprising: power battery management system, vehicle control unit, power battery management system includes:
the current magnitude relation determining module is used for determining the magnitude relation between the current and the first preset current and the second preset current;
an execution logic operation module, configured to execute an overrun power logic operation when the current is not greater than the first preset current, where the execution logic operation module is specifically configured to: determining the magnitude relation between the current actual load power of the whole vehicle and the highest allowable power of a power battery management system, and determining the magnitude relation between the duration of the current actual load power of the whole vehicle maintained by the load power and a second preset duration;
the first control state module is used for controlling the state of the main contactor according to the result of the over-limit power logic operation;
the second control state module is used for controlling the state of the main contactor according to the relationship between the duration time of the current and the first preset time length under the condition that the current is greater than the first preset current and less than the second preset current;
the third control state module is used for controlling the state of the main contactor or triggering the fuse to be actively fused according to the size relation between the duration time of the current and the first preset time length and in combination with the type selection of the fuse under the condition that the current is not less than the second preset current;
the vehicle control unit comprises:
the actual power module is used for obtaining the current actual power of the power battery management system according to actual operation parameters, and the actual operation parameters come from the power battery management system;
and the decision control module is used for controlling the state of the main contactor according to the current actual power of the power battery management system and the duration of the power battery management system for keeping the current actual power.
9. An electric vehicle, characterized in that the electric vehicle comprises: a control system;
the control system is adapted to perform the method according to any of claims 1-6.
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