CN114069564A - Relay protection circuit, method, battery management system and electric vehicle - Google Patents
Relay protection circuit, method, battery management system and electric vehicle Download PDFInfo
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- CN114069564A CN114069564A CN202010779235.0A CN202010779235A CN114069564A CN 114069564 A CN114069564 A CN 114069564A CN 202010779235 A CN202010779235 A CN 202010779235A CN 114069564 A CN114069564 A CN 114069564A
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- circuit
- relay
- driving circuit
- timing
- enabling
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators
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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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- 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 embodiment of the application provides a relay protection circuit, a relay protection method, a battery management system and an electric vehicle. The relay protection circuit includes: the input end of the voltage detection circuit is electrically connected with the first end of the drive circuit of the relay; the output end of the voltage detection circuit is electrically connected with the input end of the enabling circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, the voltage detection circuit sends a working instruction to the enabling circuit; the output end of the enabling circuit is electrically connected with the second end of the driving circuit, and the enabling circuit outputs a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal. This application detects the supply voltage among the drive circuit through relay protection circuit, when the contact actuation voltage of this supply voltage unsatisfied relay, output control signal for drive circuit is according to control signal control relay disconnection, prevents to take place because the contact adhesion of relay, the unable potential safety hazard that breaks off and cause.
Description
Technical Field
The embodiment of the application relates to the field of electric vehicles, in particular to a relay protection circuit, a relay protection method, a battery management system and an electric vehicle.
Background
A Battery Management System (BMS) of an electric vehicle is an important System for controlling a power Battery on the electric vehicle, and for example, the BMS is used for controlling a high voltage of a Battery pack to be charged and discharged, monitoring a state of a Battery cell, monitoring a total current of the Battery pack, estimating a state of the Battery pack, and the like.
The Vehicle Control Unit (VCU) is used for controlling the starting, running, advancing and retreating, speed and stopping of a motor of the electric automobile and core Control Unit elements of other electronic devices, the VCU sends Control requests of high voltage charging and discharging of a battery pack to the BMS, and the BMS realizes the switching-on and switching-off of a high voltage system by controlling the switching-on and switching-off of a relay, so that the charging and discharging requests of the VCU are met.
However, a power supply for supplying power to a power relay, such as a standby lead-acid battery (12V) for a whole vehicle and a vehicle-mounted DCDC power supply, is used by a plurality of electrical appliances, and in a complex power utilization environment, the voltage of the power supply is easy to fluctuate abnormally, which may cause the shaking of relay contacts in a serious case, and multiple arc-discharge causes contact adhesion, which means that at the moment when a high-voltage system of a battery pack is switched on, the power relay draws out an arc before contact, and the high-temperature arc burns and melts the contacts, so that the contacts cannot be disconnected. The contact adhesion of power relay, the emergence time is short and the shake state of relay is difficult to detect, has very big potential safety hazard, therefore it is necessary to provide a relay protection circuit and method in order to overcome above-mentioned defect.
Disclosure of Invention
In view of the above, an embodiment of the present invention provides a relay protection circuit, a relay protection method, a battery management system, and an electric vehicle, so as to overcome the defects that in the prior art, contact adhesion of a power relay occurs, the occurrence time is short, and a jitter state of the relay is not easy to detect, and a great potential safety hazard exists.
In a first aspect, an embodiment of the present application provides a relay protection circuit, where the relay protection circuit includes an enable circuit and a voltage detection circuit;
the input end of the voltage detection circuit is electrically connected with the first end of the drive circuit of the relay;
the output end of the voltage detection circuit is electrically connected with the input end of the enabling circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a working instruction is sent to the enabling circuit;
the output end of the enabling circuit is electrically connected with the second end of the driving circuit, and the enabling circuit outputs a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal.
Optionally, in an embodiment of the present application, the enabling circuit includes a timing circuit and a latch circuit, an output end of the voltage detection circuit is electrically connected to an input end of the timing circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a timing instruction is sent to the timing circuit, where the working instruction includes the timing instruction;
the output end of the timing circuit is electrically connected with the input end of the latch circuit, the timing circuit starts timing according to the timing instruction, and when the timing time is longer than the contact release time of the relay, a fault signal is sent to the latch circuit;
the output end of the latch circuit is electrically connected with the second end of the drive circuit, and the latch circuit outputs the control signal according to the fault signal, so that the drive circuit controls the relay to be switched off according to the control signal.
Optionally, in an embodiment of the present application, the protection circuit further includes a control unit, a signal feedback end of the enable circuit is electrically connected to an input end of the control unit, the enable circuit sends a feedback signal to the control unit, and the feedback signal is used to instruct the enable circuit to send the control signal to the driving circuit;
the output end of the control unit is electrically connected with the second end of the driving circuit, the control unit receives the feedback signal, and when the control unit detects that the power supply voltage of the driving circuit meets the attraction condition of the relay, the control unit sends an enabling signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal.
In a second aspect, an embodiment of the present application provides a relay protection method, where the method includes: detecting a power supply voltage of a drive circuit of the relay;
when the detected power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, generating a working instruction;
and outputting a control signal according to the working instruction, so that the driving circuit controls the relay to be switched off according to the control signal.
Optionally, in an embodiment of the present application, the outputting a control signal according to the work instruction includes: starting timing according to the timing instruction;
generating a fault signal when the timing time is greater than the contact release time of the relay;
and outputting the control signal according to the fault signal, so that the driving circuit controls the relay to be switched off according to the control signal.
Optionally, in an embodiment of the present application, after the driving circuit controls the relay to open according to the control signal, the method further includes:
and when detecting that the power supply voltage of the driving circuit meets the pull-in condition of the relay, sending an enabling signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal.
In a third aspect, an embodiment of the present application provides a battery management system, including the relay protection circuit described in any embodiment of the first aspect, so that the battery management system implements the method described in any embodiment of the second aspect or the second aspect through the relay protection circuit.
In a fourth aspect, the embodiment of the present application provides an electric vehicle, including the battery management system as described in the third aspect, and by providing the battery management system as described in the third aspect in the electric vehicle, the control unit of the electric vehicle can make the contacts of the relay no longer attract when the attraction condition of the relay is not satisfied, thereby avoiding the occurrence of a fault caused by adhesion of the contacts of the relay in the electric vehicle, and effectively improving the safety factor of the electric vehicle.
The embodiment of the application provides a relay protection circuit, a relay protection method, a battery management system and an electric vehicle. The relay protection circuit comprises an enabling circuit and a voltage detection circuit, wherein the input end of the voltage detection circuit is electrically connected with the first end of a drive circuit of the relay; the output end of the voltage detection circuit is electrically connected with the input end of the enabling circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, the voltage detection circuit sends a working instruction to the enabling circuit; the output end of the enabling circuit is electrically connected with the second end of the driving circuit, and the enabling circuit outputs a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal. This application is connected through the drive circuit with the voltage detection circuit among the relay protection circuit and relay, when the supply voltage who detects among the drive circuit is less than the contact actuation voltage of relay, generates the work order for drive circuit controls the relay disconnection according to the control signal of enabling circuit output, prevents to take place because the contact adhesion of relay, the unable potential safety hazard that causes that breaks off.
Drawings
Some specific embodiments of the present application will be described in detail below by way of illustration and not limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:
fig. 1 is a structural diagram of a relay protection circuit according to an embodiment of the present disclosure;
fig. 2 is a structural diagram of another relay protection circuit provided in an embodiment of the present application;
fig. 3 is a structural diagram of a relay protection circuit according to another embodiment of the present disclosure;
fig. 4 is a structural diagram of another relay protection circuit provided in the embodiment of the present application;
fig. 5 is a flowchart of a relay protection method according to an embodiment of the present application.
Detailed Description
The following further describes specific implementation of the embodiments of the present invention with reference to the drawings.
In the description of the present application, it is to be noted that unless otherwise explicitly stated or limited, the term "electrically connected" may be directly connected or indirectly connected through an intermediate member, or may be a communication between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
The first embodiment,
The relay protection circuit structure diagram comprises an enabling circuit and a voltage detection circuit, wherein the input end of the voltage detection circuit is electrically connected with the first end of a drive circuit of a relay; the output end of the voltage detection circuit is electrically connected with the input end of the enabling circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, the voltage detection circuit sends a working instruction to the enabling circuit; the output end of the enabling circuit is electrically connected with the second end of the driving circuit, and the enabling circuit outputs a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal.
Optionally, fig. 1 is a structural diagram of a relay protection circuit provided in an embodiment of the present application, as shown in fig. 1, a relay protection circuit 100 includes a voltage detection circuit 110 and an enable circuit 120, an input end of the voltage detection circuit 110 is electrically connected to a first end of a drive circuit of a relay, the voltage detection circuit 110 is configured to detect a supply voltage of the drive circuit, the supply voltage of the drive circuit in fig. 1 is derived from an on-vehicle DCDC and/or lead-acid battery (12V), an output end of the voltage detection circuit 110 is electrically connected to an input end of the enable circuit 120, an output end of the enable circuit 120 is electrically connected to a second end of the drive circuit, an output end of the drive circuit is electrically connected to the relay, and the drive circuit is configured to control opening and closing of the relay. It should be noted that the voltage detection circuit 110 in the present application may be any type of voltage detection circuit, and as long as a circuit capable of detecting the power supply voltage in real time is within the protection range of the present application, the present application is not limited thereto, and the enable circuit 120 in the present application may be any type of enable circuit, as long as the enable circuit can output the control signal according to the working instruction sent by the voltage detection circuit 110, so that the circuit that the drive circuit controls the contact of the relay to no longer pull in according to the control signal is within the protection range of the present application, and the present application is not limited thereto.
It should be noted that the relay includes at least one set of contacts, and a stationary contact and a movable contact are provided in one set of contacts, and if the movable contact and the stationary contact are separated, the relay is disconnected, and if the movable contact and the stationary contact are attracted, the relay is closed. Under normal conditions, when the supply voltage of the drive circuit of the relay is greater than or equal to the pull-in voltage of the relay contact, the contact of the relay pulls in, and the relay is in the closed state. Because on-vehicle DCDC and/or lead acid battery (12V) not only supply power for the drive circuit of relay, still supply power for a plurality of electrical apparatus simultaneously, can cause supply voltage to drop by a wide margin when the voltage of on-vehicle DCDC and/or lead acid battery (12V) receives other electrical apparatus influences, consequently the phenomenon of the voltage abnormal fluctuation of power supply appears easily, when the supply voltage of relay drive circuit appears undulant, relay coil actuation dynamics reduces, can cause the contact of relay to shake under the serious condition, draw the arc many times and cause the relay contact adhesion, unable normal disconnection, this relay contact adhesion process emergence time is short, and the shake state of relay is difficult to detect, if discovery and handling in time, can threaten battery management system, whole vehicle's safety very likely. This application is through setting up relay protection circuit, this relay protection circuit's voltage detection circuit is connected with the drive circuit of relay, through the supply voltage curve in the voltage detection circuit real-time detection drive circuit, when the supply voltage who detects drive circuit is less than the actuation voltage of relay, send the work order to the enabling circuit, make the enabling circuit according to this work order output control signal, thereby drive circuit is no longer the actuation according to control signal control relay, prevent to take place the relay because the unstable contact that leads to of supply voltage takes place the adhesion, the potential safety hazard that can't break off and cause.
Optionally, in an embodiment of the present application, the enabling circuit includes a timing circuit and a latch circuit; the output end of the voltage detection circuit is electrically connected with the input end of the timing circuit, when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a timing instruction is sent to the timing circuit, and the working instruction comprises the timing instruction; the output end of the timing circuit is electrically connected with the input end of the latch circuit, the timing circuit starts timing according to a timing instruction, and when the timing time is longer than the contact release time of the relay, a fault signal is sent to the latch circuit; the output end of the latch circuit is electrically connected with the second end of the drive circuit, and the latch circuit outputs a control signal according to the fault signal, so that the drive circuit controls the relay to be disconnected according to the control signal.
Optionally, as shown in fig. 2, fig. 2 is a structural diagram of another relay protection circuit provided in this embodiment of the present application, where the relay protection circuit 100 includes a voltage detection circuit 110, a timing circuit 121, and a latch circuit 122, where the enable circuit 120 includes the timing circuit 121 and the latch circuit 122, an input end of the voltage detection circuit 110 is electrically connected to a first end of a driving circuit of the relay, a supply voltage of the driving circuit may be derived from an on-vehicle DCDC and/or lead-acid battery (12V), an output end of the voltage detection circuit 110 is electrically connected to an input end of the timing circuit 121, and when the voltage detection circuit 110 detects that the supply voltage of the driving circuit is lower than a pull-in voltage of the relay, a timing instruction is sent to the timing circuit 121; the output end of the timing circuit 121 is electrically connected to the input end of the latch circuit 122, the timing circuit 121 starts timing according to a timing instruction until the voltage detection circuit 110 detects that the power supply voltage of the driving circuit is greater than the contact pull-in voltage of the relay, which is described by taking 2 examples here. When the timing time is longer than the contact release time of the relay, the contacts of the relay can be bounced off, the separated relay contacts can not be attracted again in a short time, otherwise, the relay can be burnt out with load and arc, the software program instruction still sends a relay attraction instruction to the driving circuit, and the timing circuit 121 generates a fault signal and sends the fault signal to the latch circuit 122 in the embodiment of the application; the output end of the latch circuit 122 is electrically connected with the second end of the drive circuit, the latch circuit 122 outputs a control signal according to a fault signal, so that the drive circuit controls the relay to be disconnected according to the control signal, the latch circuit latches the enable signal of the drive circuit from a hardware circuit and is not controlled by a software program instruction any more, the contact of the relay is not attracted again, and the potential safety hazard caused by the fact that the contact of the relay is adhered and cannot be disconnected due to the fact that the supply voltage is unstable is prevented from occurring. It should be noted that latching is to temporarily store a signal to maintain a certain state, the timing circuit 121 in the present application may be any type of timing circuit, and the present application is not limited thereto as long as the circuit can perform timing according to a timing instruction, and the latch circuit 122 in the present application may be any type of latch circuit, and the present application is not limited thereto as long as the circuit can output a control signal according to failure information. The enabling circuit comprises a timing circuit and a latch circuit, wherein when the detected power supply voltage is lower than a specified voltage threshold value, the timing circuit performs time timing, and when the timing time is less than or equal to the contact release time of the relay, namely when the power supply voltage is less than the contact pull-in voltage of the relay within the preset time, the latch circuit does not immediately latch the enabling signal of the driving circuit, namely, if the time that the power supply voltage is lower than the specified voltage threshold value is less than the specified time threshold value, the relay continues to pull in; if the time that the voltage of the power supply is lower than the specified voltage threshold is longer than the specified time threshold, the latch circuit latches the enabling signal of the relay driving circuit, the pull-in requirement is not responded any more, and the normal work of the relay is further ensured.
Optionally, in an embodiment of the present application, the protection circuit further includes a control unit; the signal feedback end of the enabling circuit is electrically connected with the input end of the control unit, the enabling circuit sends a feedback signal to the control unit, and the feedback signal is used for indicating the enabling circuit to send a control signal to the driving circuit; the output end of the control unit is electrically connected with the second end of the driving circuit, the control unit receives the feedback signal, and when the control unit detects that the power supply voltage of the driving circuit meets the attraction condition of the relay, the control unit sends an enabling signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal.
Optionally, as shown in fig. 3, fig. 3 is a structural diagram of another relay protection circuit provided in the embodiment of the present application, and further, the protection circuit further includes a control Unit (MCU), the MCU in fig. 3 is a MCU 130, on the basis of fig. 1, the signal feedback terminal of the enable circuit 120 in fig. 3 is electrically connected to the input terminal of the control unit 130, the enable circuit 120 sends a feedback signal to the control unit 130, the feedback signal is used to instruct the enable circuit 120 to send a control signal to the driving circuit, the feedback signal includes, but is not limited to, information that the power supply voltage of the relay has an unexpected fluctuation, the driving circuit of the relay is locked, and after the enable circuit 120 sends the control signal to the driving circuit, the driving circuit controls the relay to be turned off according to the control signal, the relay is temporarily not allowed to be pulled in, and the enabling circuit 120 feeds back the situation to the control unit 130 through a feedback signal. Here, it should be noted that, in the present application, the power supply voltage of the driving circuit may be collected in real time by the control unit 130, or the power supply voltage of the driving circuit may be detected in real time by the voltage detection circuit 110, and the real-time power supply voltage is sent to the control unit 130 through the enabling circuit 120, or the power supply voltage of the driving circuit may be collected in real time by other devices, and the real-time power supply voltage is sent to the control unit 130, where this is not limited in the embodiment of the present application. When detecting that the power supply voltage of the driving circuit meets the pull-in condition of the relay, the control unit 130 sends an enable signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enable signal. Optionally, the control unit 130 monitors the high-voltage electrification condition, and determines whether the re-attracting condition of the relay is satisfied according to the power supply voltage state and the high-voltage electrification condition of the driving circuit, where the attracting condition may be, but is not limited to, the attracting voltage, for example, it is determined whether the power supply voltage of the driving circuit is greater than or equal to the contact attracting voltage of the relay, and if so, although the power supply voltage of the driving circuit is less than the contact attracting voltage of the relay, the whole high-voltage electrification condition and the power supply voltage state satisfy the attracting condition of the relay, it can be understood that the attracting condition may also be other conditions set according to actual conditions, and therefore, the embodiment of the present application is not limited. If the pull-in condition is satisfied, the control unit 130 sends an enable signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enable signal, for example, the control unit 130 sends the enable signal to the driving circuit, so that the driving circuit can control the relay to be closed according to the enable signal, and if so, the latch circuit 122 latches the enable signal of the driving circuit, outputs a control signal to the driving circuit, the control unit 130 releases the enable signal of the driving circuit, so that the driving circuit can control the relay to be closed according to the enable signal, and the embodiment of the present application is not limited. The relay protection circuit in the embodiment of the application further comprises a control unit, the relay protection circuit detects the power supply voltage curve of the relay driving circuit in real time, and when the fact that the driving circuit of the relay does not meet the pull-in condition of the relay is detected, the relay is controlled to be disconnected; and detecting the high-voltage electrification condition and the power supply voltage state in real time, and releasing the drive circuit of the relay when the high-voltage electrification condition and the power supply voltage state of the drive circuit meet the pull-in condition of the relay so that the drive circuit controls the relay to be closed according to the enabling signal.
In the embodiment of the present application, when the relay protection circuit 100 protects a relay, in a normal power supply working state, in an achievable manner, the enable circuit 120 may output an enable signal to the driving circuit to enable the enable signal of the driving circuit to be in a normal working state, and in another achievable manner, the enable circuit 120 is not triggered, and only the control unit 130 controls the enable signal of the driving circuit to enable the enable signal of the driving circuit to be in a normal working state, which does not limit the embodiment of the present application; when the power supply voltage is lower than the pull-in voltage of the relay, the enable circuit 120 latches the enable signal of the driving circuit and outputs a control signal to the driving circuit, so that the driving circuit controls the relay to be disconnected according to the control signal, and when the pull-in condition of the relay is met, the control unit 130 releases the enable signal of the driving circuit, so that the driving circuit controls the relay to be closed according to the enable signal. The detection of the power supply voltage curve of the relay driving circuit is achieved through hardware in the application, the closing and the opening of the control relay are achieved through the hardware circuit, the situation that software cannot respond timely is avoided, the timeliness and the accuracy of the relay protection action are guaranteed, and the normal work of the relay is further guaranteed.
Optionally, in an embodiment of the present application, the protection circuit includes a control unit, a voltage detection circuit, a latch circuit, and a timing circuit, as shown in fig. 4, fig. 4 is a structural diagram of another relay protection circuit provided in the embodiment of the present application, a signal feedback end of the latch circuit 122 is electrically connected to an input end of the control unit 130, and an input end of the voltage detection circuit 110 is electrically connected to a first end of a driving circuit of the relay; the output end of the voltage detection circuit 110 is electrically connected with the input end of the timing circuit 121, and when the voltage detection circuit 110 detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a timing instruction is sent to the timing circuit 121; the output end of the timing circuit 121 is electrically connected with the input end of the latch circuit 122, the timing circuit 121 starts timing according to a timing instruction, and when the timing time is longer than the contact release time of the relay, a fault signal is sent to the latch circuit 122; the output end of the latch circuit 122 is electrically connected with the second end of the driving circuit, and the latch circuit 122 outputs a control signal according to the fault signal, so that the driving circuit controls the relay to be disconnected according to the control signal; a signal feedback end of the latch circuit 122 is electrically connected with an input end of the control unit 130, the latch circuit 122 sends a feedback signal to the control unit 130, and the feedback signal is used for indicating the latch circuit 122 to send a control signal to the driving circuit; the output end of the control unit 130 is electrically connected to the second end of the driving circuit, the control unit 130 receives the feedback signal, and when the control unit 130 detects that the power supply voltage of the driving circuit meets the pull-in condition of the relay, the control unit 130 sends an enable signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enable signal.
Example II,
An embodiment of the present application provides a relay protection method, as shown in fig. 5, fig. 5 is a relay protection method provided in an embodiment of the present application, and the relay protection method includes the following steps;
step 101, detecting the power supply voltage of the driving circuit of the relay.
The drive circuit is used for controlling the on or off of the relay. For example, the power supply voltage of the driving circuit can be derived from a vehicle-mounted DCDC and/or lead-acid battery (12V), the vehicle-mounted DCDC and/or lead-acid battery (12V) not only supplies power for the driving circuit of the relay, but also supplies power for a plurality of electrical appliances at the same time, and when the vehicle-mounted DCDC and/or lead-acid battery is influenced by other electrical appliances, the voltage can drop greatly, so that the phenomenon of abnormal fluctuation of the voltage of the power supply is easy to occur. This application can pass through voltage detection circuit real-time detection relay drive circuit's supply voltage, also can detect relay drive circuit's supply voltage through other circuit, does not do the restriction to this application embodiment.
And 102, generating a working instruction when the detected power supply voltage of the driving circuit is lower than the pull-in voltage of the relay.
The power supply voltage curve of the driving circuit is detected in real time, and when the fact that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay is detected, a working instruction is generated.
And 103, outputting a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal.
Optionally, in an implementation manner, the control signal is output according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal; in another implementation manner, the enable signal of the driving circuit is latched according to the working instruction, and the pull-in requirement is no longer responded, so that the relay is temporarily no longer pulled in, and the embodiment of the application is not limited.
Optionally, in an embodiment of the present application, the work order comprises a timing order and step 103 may comprise steps 103a-103 c.
Step 103a, starting timing according to the timing command.
And 103b, generating a fault signal when the timing time is greater than the contact release time of the relay.
It should be noted that, for a specific relay, the release time is specified and has a certain range, so for the relay in use, when the closing time of the relay satisfies the contact release time, the contacts of the relay should be in a separated state, that is, when the timing time is longer than the contact release time of the relay, the contacts of the relay will pop open to generate a fault signal.
And 103c, outputting a control signal according to the fault signal, so that the driving circuit controls the relay to be disconnected according to the control signal.
It should be noted that, when the timing time is longer than the contact release time of the relay, the contacts of the relay may bounce, the separated relay contacts may not be pulled in a short time, otherwise, the relay may be burned out by an arc with load, and the software program instruction at this time still sends the relay pull-in instruction to the driving circuit.
In the embodiment of the application, when the timing time is less than or equal to the contact release time of relay, namely when the supply voltage is less than the contact actuation voltage of relay in the preset time, can not latch the enable signal of the driving circuit immediately, only when the timing time is greater than the contact release time of relay, generate the fault signal, and output the control signal according to the fault signal, make the driving circuit control the relay disconnection according to the control signal, prevent the relay because the unstable contact that leads to of supply voltage from taking place the adhesion, the potential safety hazard that can't break off and cause.
Optionally, in an embodiment of the present application, after passing through step 101 and step 103, the driving circuit controls the relay to be turned off according to the control signal, and step 104 may also be performed.
And 104, when the fact that the power supply voltage of the driving circuit meets the pull-in condition of the relay is detected, sending an enabling signal to the driving circuit, and enabling the driving circuit to control the relay to be closed according to the enabling signal.
Optionally, in this embodiment of the application, after the driving circuit controls the relay to be turned off according to the control signal, the power supply voltage and the high-voltage live condition of the relay driving circuit are continuously detected in real time, and whether the re-pull-in condition of the relay is met is determined according to the power supply voltage state and the high-voltage live condition of the driving circuit, where the pull-in condition may be, but is not limited to, the pull-in voltage. When the condition that the power supply voltage state of the driving circuit meets the re-attracting condition of the relay is detected, in an achievable mode, an enabling signal is sent to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal; in another implementation manner, the relay driving circuit is released, so that the driving circuit controls the relay to be closed according to the enable signal, which is not limited in this embodiment of the application. When the whole protection circuit detects that the drive circuit of the relay does not meet the pull-in condition of the relay, the relay is controlled to be disconnected, the high-voltage electrified condition and the power supply voltage state are detected in real time, and when the high-voltage electrified condition and the power supply voltage state meet the pull-in condition of the relay, the relay is controlled to be closed. According to the relay protection method in the embodiment of the application, the on and off of the relay are controlled through the real-time detection of the power supply voltage curve of the relay driving circuit, the timeliness and the accuracy of the relay protection action are ensured, and therefore the normal work of the relay is further ensured.
Example III,
Based on the relay protection circuit described in the first embodiment, the present application provides a Battery Management System, where the Battery Management System (BMS) includes, but is not limited to, a control unit, a relay drive circuit, and a relay protection circuit, and a power supply for supplying power to the relay drive circuit may be a standby lead-acid Battery (12V) and/or an on-board DCDC power supply for a vehicle, and the BMS is an important System for controlling a power Battery on an electric vehicle, and is used for controlling, but is not limited to, a high voltage up and down of a Battery pack, a state of the Battery pack SOX, and the like, where the state of the SOX includes, but is not limited to, SOC and SOP estimation, and the SOC is used for indicating a state of charge of a power lithium Battery and reflecting safety and a capacity attenuation degree of the lithium Battery pack, and the state of the Battery SOP is used for indicating a state of Battery power and is generally represented by a short-time peak power value. Generally, when the BMS implements the high-voltage power-up and power-down functions of a battery pack, power-up and power-down Control requests come from a Vehicle Control Unit (VCU), the VCU is an assembly Control Unit of an electric Vehicle power system and is responsible for coordinating the operations of various components such as an engine, a driving motor, a transmission case, a power battery, and the like, and the VCU sends the power-up and power-down Control requests to the BMS through a data bus, such as a CAN or a CANFD. The BMS controls High Side Drive (HSD) and Low Side Drive (LSD) of a relay coil drive circuit to realize the opening and closing of the relay. In the embodiment of the application, the relay protection circuit is arranged in the BMS, when the power supply voltage of the relay drive circuit does not meet the attraction voltage, the relay protection circuit latches the enabling signal of the relay drive circuit, so that the relay drive circuit controls the contact of the relay not to attract any more, and informs the situation to the control unit in the BMS, the control unit judges whether the power utilization environment meets the contact attraction condition of the relay according to the collected power supply voltage state and the high-voltage electrification condition of the relay drive circuit, and if the current power utilization environment does not meet the contact attraction condition of the relay, the relay is still in the off state; if current power consumption environment satisfies the contact actuation condition of relay, then the control unit unlocks relay drive circuit, releases relay drive circuit for relay drive circuit continues to control the closure and the disconnection of relay, thereby avoids taking place the BMS because the relay contact takes place the trouble that the adhesion leads to, has effectively improved BMS factor of safety.
Example four,
Based on the relay protection circuit described in the first embodiment, the embodiment of the application provides an electric vehicle, the electric vehicle can be but not limited to a pure electric vehicle, a hybrid electric vehicle and the like, and the battery management system described in the third embodiment is arranged in the electric vehicle, so that the control unit can enable the contact of the relay not to be attracted any more when the attraction condition of the relay is not met, the fault caused by adhesion of the relay contact is avoided, and the safety factor of the electric vehicle is effectively improved.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (8)
1. The relay protection circuit is characterized by comprising an enabling circuit and a voltage detection circuit;
the input end of the voltage detection circuit is electrically connected with the first end of the drive circuit of the relay;
the output end of the voltage detection circuit is electrically connected with the input end of the enabling circuit, and when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a working instruction is sent to the enabling circuit;
the output end of the enabling circuit is electrically connected with the second end of the driving circuit, and the enabling circuit outputs a control signal according to the working instruction, so that the driving circuit controls the relay to be disconnected according to the control signal.
2. The protection circuit of claim 1, wherein the enabling circuit comprises a timing circuit and a latch circuit;
the output end of the voltage detection circuit is electrically connected with the input end of the timing circuit, when the voltage detection circuit detects that the power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, a timing instruction is sent to the timing circuit, and the working instruction comprises the timing instruction;
the output end of the timing circuit is electrically connected with the input end of the latch circuit, the timing circuit starts timing according to the timing instruction, and when the timing time is longer than the contact release time of the relay, a fault signal is sent to the latch circuit;
the output end of the latch circuit is electrically connected with the second end of the drive circuit, and the latch circuit outputs the control signal according to the fault signal, so that the drive circuit controls the relay to be switched off according to the control signal.
3. The protection circuit of claim 1, further comprising a control unit;
the signal feedback end of the enabling circuit is electrically connected with the input end of the control unit, the enabling circuit sends a feedback signal to the control unit, and the feedback signal is used for indicating the enabling circuit to send the control signal to the driving circuit;
the output end of the control unit is electrically connected with the second end of the driving circuit, the control unit receives the feedback signal, and when the control unit detects that the power supply voltage of the driving circuit meets the attraction condition of the relay, the control unit sends an enabling signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal.
4. A relay protection method applied to the relay protection circuit according to any one of claims 1 to 3, characterized by comprising:
detecting a power supply voltage of a drive circuit of the relay;
when the detected power supply voltage of the driving circuit is lower than the pull-in voltage of the relay, generating a working instruction;
and outputting a control signal according to the working instruction, so that the driving circuit controls the relay to be switched off according to the control signal.
5. The method of claim 4, wherein the work order comprises a timing order, and wherein outputting a control signal based on the work order comprises:
starting timing according to the timing instruction;
generating a fault signal when the timing time is greater than the contact release time of the relay;
and outputting the control signal according to the fault signal, so that the driving circuit controls the relay to be switched off according to the control signal.
6. The method of claim 4, wherein after the drive circuit controls the relay to open according to the control signal, the method further comprises:
and when detecting that the power supply voltage of the driving circuit meets the pull-in condition of the relay, sending an enabling signal to the driving circuit, so that the driving circuit controls the relay to be closed according to the enabling signal.
7. A battery management system, characterized in that the battery management system comprises: the relay protection circuit of any of claims 1-3.
8. An electric vehicle, characterized in that the electric vehicle comprises: the battery management system of claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010779235.0A CN114069564A (en) | 2020-08-05 | 2020-08-05 | Relay protection circuit, method, battery management system and electric vehicle |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010779235.0A CN114069564A (en) | 2020-08-05 | 2020-08-05 | Relay protection circuit, method, battery management system and electric vehicle |
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| CN114069564A true CN114069564A (en) | 2022-02-18 |
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| CN202010779235.0A Pending CN114069564A (en) | 2020-08-05 | 2020-08-05 | Relay protection circuit, method, battery management system and electric vehicle |
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