CN110789347B - Load on-off control system and control method thereof, and electric automobile - Google Patents

Load on-off control system and control method thereof, and electric automobile Download PDF

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Publication number
CN110789347B
CN110789347B CN201911042503.4A CN201911042503A CN110789347B CN 110789347 B CN110789347 B CN 110789347B CN 201911042503 A CN201911042503 A CN 201911042503A CN 110789347 B CN110789347 B CN 110789347B
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voltage
contactor
circuit
resistor
battery pack
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CN110789347A (en
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靳彦红
刘春�
罗黎艳
于安博
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Hefei Yangguang Electric Power Technology Co ltd
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Hefei Yangguang Electric Power Technology Co ltd
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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
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • 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
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • 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
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention discloses a load on-off control system and a control method thereof, and an electric automobile, wherein the load on-off control system comprises a high-voltage battery pack, a contactor circuit, a first voltage acquisition circuit, a second voltage acquisition circuit and a control circuit, wherein the first voltage acquisition circuit and the second voltage acquisition circuit respectively acquire the voltage of the input end of the contactor circuit to the ground and the voltage at two ends of the high-voltage battery pack, and when the voltage variation of the voltage of the input end of the contactor circuit to the ground relative to the voltage at two ends of the high-voltage battery pack exceeds a first preset voltage threshold value, the contactor circuit is determined to successfully execute a switch switching action; when the voltage variation of the input end of the contactor circuit to the ground relative to the voltage variation of the two ends of the high-voltage battery pack is within a first preset voltage threshold value, the fact that the contactor circuit does not successfully execute the switching action is determined, and therefore accuracy and reliability of detecting the switching state of the contactor are improved.

Description

Load on-off control system and control method thereof, and electric automobile
Technical Field
The invention relates to the technical field of electric automobiles, in particular to a load on-off control system and a control method thereof, and an electric automobile.
Background
With the strong support of the country for new energy vehicles, the development of electric vehicles is more and more rapid. The main power source of the electric automobile is electric power, the working voltage of the whole high-voltage loop reaches hundreds of volts, and whether the high-voltage contactor is correctly attracted and disconnected can influence the safety of the electric automobile and a driver.
The existing electric automobile contactor state detection scheme comprises:
(1) the contactor is internally provided with a mechanical small switch, when the main contact is attracted, the auxiliary insulating part extrudes the small switch to enable the small switch to be conducted, the disconnection and attraction states of the small switch are detected through an external circuit, and the on-off state of the main contact of the contactor is judged.
(2) And the two ends of the main contact of the contactor respectively detect bus voltage, the disconnection state of the contactor is judged when the voltage difference of the buses at the two ends of the contactor is larger, and the closing of the contactor is judged when the voltage difference of the buses at the two ends of the contactor is basically zero or the voltage rise rate of the rear end of the contactor is very small.
(3) And injecting a low-voltage detection signal into a main contact of the direct current contactor, and identifying the on-off state of the contactor through an external signal detection module.
The prior art scheme has the following defects:
(1) the detection method of the built-in auxiliary switch of the contactor comprises the following steps: the circuit is complex, the power consumption is large, the cost of the used device is high, and the reliability is low after long-time use.
(2) The detection method for sampling the rear end voltage of the contactor comprises the following steps: when the non-attraction fault occurs in the attraction process of the positive and negative bus contactors on the high voltage, whether the positive bus contactor is not attracted or the negative bus contactor is not attracted cannot be accurately detected.
(3) External injection signals and high-voltage signals are in the same path, the requirements on safety distance and electrical isolation are high, the cost of an isolation circuit is high, the influence of contact impedance of a main contact on the reliability of a judgment result is large, and the overall reliability is low.
Disclosure of Invention
The invention mainly aims to provide a load on-off control system, aiming at improving the accuracy and reliability of detecting the on-off state of a contactor.
In order to achieve the above object, the load on-off control system provided by the present invention includes a high voltage battery pack for supplying power to a load through a dc bus, a contactor circuit disposed on the dc bus and configured to perform a switching action when receiving a switching control signal, a first voltage acquisition circuit for acquiring a voltage of an input terminal of the contactor circuit to ground, a second voltage acquisition circuit for acquiring a voltage of both ends of the high voltage battery pack, and a control circuit for controlling the contactor circuit to operate when receiving a contactor control instruction, and acquiring the voltage of the input terminal of the contactor circuit to ground and the voltage of both ends of the high voltage battery pack;
when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold, determining that the contactor circuit successfully executes a switch switching action;
and when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack is within a first preset voltage threshold, determining that the contactor circuit does not successfully execute the switching action.
Preferably, the dc bus includes an anode power line connecting the anode of the high-voltage battery pack and the positive power source end of the load, and a cathode power line connecting the cathode of the high-voltage battery pack and the negative power source end of the load, the contactor circuit includes an anode contactor disposed on the anode power line, and the input end of the contactor circuit is the input end of the anode contactor.
Preferably, the contactor circuit further comprises a negative contactor arranged on the negative power line, and the negative contactor is closed and opened first when receiving the contactor control instruction;
the control circuit is further used for controlling the negative contactor and the positive contactor to sequentially execute switch switching actions after receiving a contactor control instruction, and judging whether the negative contactor executes the switch switching actions according to whether the variation of the voltage difference value between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold value.
Preferably, the contactor circuit further comprises a pre-charging contactor and a third voltage acquisition circuit, the contactor control command comprises a contactor power-on command and a contactor power-off command, and the pre-charging contactor is connected with the positive contactor in parallel;
the third voltage acquisition circuit is used for acquiring the voltage of the power supply end of the load;
the control circuit is used for controlling the negative contactor to attract and controlling the pre-charging contactor and the positive contactor to attract in a staggered manner when a power-on instruction of the contactor is received, determining that the pre-charging contactor successfully executes a switch switching action when the variation of the voltage difference between the voltage of the input end of the positive contactor to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a second preset voltage threshold, and determining that the pre-charging contactor executes a turn-off action and determining that the positive contactor executes an attraction action when the voltage difference between the voltage of the two ends of the high-voltage battery pack and the voltage of the power end of the load control device is smaller than a preset voltage;
and when the contactor power-off instruction is received, controlling the negative contactor and the positive contactor to be sequentially disconnected, and judging whether the negative contactor and the positive contactor sequentially execute switch switching actions according to whether the variation of the voltage difference value between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold value.
Preferably, the first voltage acquisition circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a first comparator;
the first end of the first resistor is connected with the positive pole of the battery pack, the second end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the positive phase input end of the first comparator are interconnected, the second end of the second resistor and the second end of the first capacitor are all grounded, the first end of the third resistor is grounded, the second end of the third resistor, the reverse phase input end of the first comparator, the first end of the fourth resistor and the first end of the second capacitor are interconnected, the output end of the first comparator, the second end of the fourth resistor and the second end of the second capacitor are interconnected, and a connection node is a signal end of the first voltage acquisition circuit.
Preferably, the second voltage acquisition circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor, a fourth capacitor and a second comparator;
the first end of the fifth resistor is connected with the positive electrode of the battery pack, the second end of the fifth resistor, the first end of the sixth resistor, the first end of the third capacitor and the positive phase input end of the second comparator are interconnected, the second end of the sixth resistor and the second end of the third capacitor are both grounded, the first end of the seventh resistor is connected with the negative electrode of the battery pack, the second end of the seventh resistor, the negative phase input end of the second comparator, the first end of the eighth resistor and the first end of the fourth capacitor are interconnected, the output end of the second comparator, the second end of the eighth resistor and the second end of the fourth capacitor are interconnected, and the connection node is the signal end of the second voltage acquisition circuit.
Preferably, the control circuit comprises a first voltage comparison circuit, a second voltage comparison circuit, a DSP processor and a controller;
the first signal input end of the first voltage comparison circuit is connected with the signal output end of the first voltage acquisition circuit, the second signal input end of the first voltage comparison circuit is connected with the signal output end of the second voltage acquisition circuit, the first signal input end of the second voltage comparison circuit is connected with the signal output end of the second voltage acquisition circuit, the second signal input end of the second voltage comparison circuit is connected with the signal output end of the first voltage acquisition circuit, the signal output end of the second voltage acquisition circuit, the signal output end of the third voltage acquisition circuit, the signal output end of the first voltage comparison circuit and the signal output end of the second voltage comparison circuit are respectively connected with the signal input end of the DSP processor, and the signal output end of the DSP processor is connected with the signal end of the controller, the control end of the controller is also connected with the controlled end of each contactor respectively;
the first voltage comparison circuit is used for comparing the voltage of the input end of the contactor circuit to the ground voltage and the voltage of the two ends of the high-voltage battery pack and outputting a first level signal to the DSP processor;
the second voltage comparison circuit is used for comparing the voltages at two ends of the high-voltage battery pack with the voltage of the input end of the contactor circuit to the ground voltage and outputting a second level signal to the DSP;
the DSP is used for determining whether each contactor executes corresponding switch switching action or not according to the first level signal, the second level signal and the voltage signal acquired by each voltage acquisition circuit, and feeding the corresponding switch switching action back to the controller;
and the controller is used for correspondingly controlling the execution switch switching action of each contactor according to the contactor control instruction, and carrying out power-on control and power-off control on the contactor circuit of the load on-off control system according to the switch switching action of each contactor fed back by the DSP processor.
Preferably, the first voltage comparison circuit comprises a third comparator, a positive phase input end of the third comparator is connected with the signal output end of the first voltage acquisition circuit, a negative phase input end of the third comparator is connected with the signal output end of the second voltage acquisition circuit, and an output end of the third comparator is connected with the signal input end of the DSP processor;
the second voltage comparison circuit comprises a fourth comparator, the positive phase input end of the fourth comparator is connected with the signal output end of the second voltage acquisition circuit, the negative phase input end of the fourth comparator is connected with the signal output end of the first voltage comparison circuit, and the output end of the fourth comparator is connected with the signal input end of the DSP processor.
The invention also provides a control method of the load on-off control system, which is used for the load on-off control system, and the control method of the load on-off control system comprises the following steps:
when a contactor control command is received, controlling a contactor circuit to act, and acquiring voltage of an input end of the contactor circuit to earth voltage and voltage of two ends of a high-voltage battery pack;
when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold, determining that the contactor circuit successfully executes a switch switching action;
and when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack is within a first preset voltage threshold, determining that the contactor circuit does not successfully execute the switching action.
The invention also provides an electric automobile which comprises the load on-off control system, wherein the load on-off control system adopts the control method of the load on-off control system.
The technical scheme of the invention is that when a contactor control instruction is received, a contactor circuit is controlled to execute a switch switching action, the voltage of an input end to ground of the contactor circuit and the voltages of two ends of a high-voltage battery pack are obtained, whether the contactor circuit executes the switch switching action is determined according to the variation of the voltage difference value of the voltage of the input end to ground of the contactor circuit and the voltages of two ends of the high-voltage battery pack, so that whether the state of the contactor circuit is good or abnormal is judged, namely, the voltage of the input end to ground of the contactor circuit and the voltages of two ends of the high-voltage battery pack are compared, whether the variation of the voltage difference value of the voltage of the input end to ground of the contactor circuit and the voltages of two ends of the high-voltage battery pack is within a preset voltage threshold value is judged, and when the variation is, when outside presetting the voltage threshold, then show that the contactor circuit correctly switches operating condition according to control signal, the contactor circuit is in normal operating condition, only need gather the voltage of contactor circuit's input terminal to ground voltage and high-voltage battery group both ends respectively through two way acquisition circuit in this scheme, moreover, the steam generator is simple in structure, and regard high-voltage battery group as the reference volume, the voltage of contactor circuit's input terminal to ground voltage and high-voltage battery both ends all keeps dynamic change when the battery is full of electricity and low-power, keep the relative voltage balance, it need not to follow the setting to predetermine the voltage threshold, the control degree of difficulty has been reduced, thereby improve accuracy and the reliability of detecting contactor on-off state.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a block diagram of an embodiment of a load on-off control system according to the present invention;
fig. 2 is a schematic circuit structure diagram of an embodiment of a first voltage acquisition circuit in the load on-off control system according to the present invention;
fig. 3 is a schematic circuit structure diagram of an embodiment of a second voltage acquisition circuit in the load on-off control system according to the present invention;
FIG. 4 is a schematic circuit diagram of an embodiment of a control circuit in the load on-off control system according to the present invention;
fig. 5 is a flowchart illustrating an embodiment of a control method of the load on-off control system according to the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the descriptions relating to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout is: the method comprises three parallel schemes, wherein the scheme is taken as an A/B (A/B) as an example, the scheme comprises the scheme A, the scheme B or the scheme A and the scheme B simultaneously satisfy, in addition, the technical schemes between the various embodiments can be combined with each other, but the technical schemes must be based on the realization of the technical schemes by a person skilled in the art, and when the technical schemes are mutually contradictory or can not be realized, the combination of the technical schemes is not considered to exist, and the protection scope of the invention is not within the protection scope of the invention.
The invention provides a load on-off control system.
As shown in fig. 1, fig. 1 is a schematic block diagram of an embodiment of a load on-off control system of the present invention, where the load on-off control system includes:
a high-voltage battery pack BAT for supplying power to a load through a dc bus;
a contactor circuit 10, which is arranged on the direct current bus and is used for executing switch switching action when receiving a switch control signal;
the first voltage acquisition circuit 20 is used for acquiring the voltage of the input end of the contactor circuit 10 to the ground;
a second voltage acquisition circuit 30 for acquiring voltages at both ends of the high-voltage battery pack BAT; and
the control circuit 50 is used for controlling the action of the contactor circuit 10 when receiving a contactor control command, and acquiring the voltage of the input end of the contactor circuit 10 to the ground voltage and the voltage of the two ends of the high-voltage battery pack BAT;
when the variation of the voltage difference between the voltage of the input terminal to the ground of the contactor circuit 10 and the voltage of the two terminals of the high-voltage battery pack BAT exceeds a first preset voltage threshold, determining that the contactor circuit 10 successfully executes a switching action;
when the variation of the voltage difference between the input terminal-to-ground voltage of the contactor circuit 10 and the voltage across the high-voltage battery pack BAT is within the first preset voltage threshold, it is determined that the contactor circuit 10 has not successfully performed the switching action.
In this embodiment, the load on-off control system may be a load system powered by a high-voltage battery pack BAT, such as a battery power supply system of an electric vehicle, a UPS power supply module in a power distribution system, and the like, where the high-voltage battery pack BAT is connected to a load through a contactor circuit 10, and outputs a dc power supply to the load according to a switching state of the contactor circuit 10, and the load may be a motor, a fan, a compressor, and the like in the electric vehicle, and the high-voltage battery pack BAT includes a plurality of single batteries connected in series and parallel.
The contactor circuit 10 is used for being switched on or off correspondingly according to a control signal to provide direct current power to a load, and one or more of a positive contactor K1, a negative contactor K2 and a pre-charging contactor K3 can be included in the contactor circuit 10.
The first voltage acquisition circuit 20 is used for acquiring the voltage to ground of the input terminal of the contactor circuit 10, when the switching state of the contactor circuit 10 is switched, the load is connected or disconnected, so that the voltage value of the direct current bus to the ground is changed, and further the voltage value acquired by the first voltage acquisition circuit 20 is changed, and whether the contactor in the contactor circuit 10 executes the switching action or not can be judged according to the change of the voltage value of the first voltage acquisition circuit 20, it can be understood that the input terminal of the contactor circuit 10 is connected with the output terminal of the high-voltage battery pack BAT, that is, the first voltage acquisition circuit 20 is used for acquiring the voltage to ground of the output terminal of the high-voltage battery pack BAT, in order to reduce the voltage change of the output terminal of the high-voltage battery pack BAT caused by the charging and discharging of the high-voltage battery pack BAT, and further the voltage change amount of the input terminal of the contactor circuit, when the first preset voltage threshold value needs to be set, the voltage of the high-voltage battery pack BAT is acquired by setting the second voltage acquisition circuit 30, the voltage to ground at the input end of the contactor circuit 10 is compared with the voltage value of the high-voltage battery pack BAT, the voltage variation before and after switching of the contactor circuit 10 is judged, namely when the contactor circuit 10 is in the first switching state, the voltage to ground at the input end of the contactor circuit 10 is calculated and compared with the voltage of the high-voltage battery pack BAT, when the contactor circuit 10 receives a contactor control command to switch the switching state, the voltage to ground at the input end of the contactor circuit 10 relative to the voltage value of the high-voltage battery pack BAT is acquired, whether the contactor correctly executes the switching action can be determined according to the voltage variation before and after the voltage variation and the first preset voltage threshold value, when the voltage variation is within the preset voltage threshold value, the problem of adhesion or fault is indicated that the contactor circuit 10 does not correctly switch the working state according to the control signal, and when the voltage is out of the preset voltage threshold value, the contactor circuit 10 correctly switches the working state according to the control signal and the contactor circuit 10 is in the normal working state.
The first voltage acquisition circuit 20 and the second voltage acquisition circuit 30 may acquire corresponding voltage values in a manner of resistor voltage division or a transformer, and are specifically selected according to actual requirements.
Only need gather the voltage at contactor circuit 10's input terminal to ground voltage and high-voltage battery group BAT both ends respectively through two way acquisition circuit in this scheme, simple structure, and regard high-voltage battery group BAT as the reference volume, contactor circuit 10's input terminal to ground voltage and the voltage at high-voltage battery group BAT both ends all keep dynamic change when the battery is full of electric quantity and low electric quantity, keep relative voltage balance, predetermine the voltage threshold value and need not to follow the setting, reduced the control degree of difficulty, thereby improve accuracy and the reliability of detecting contactor on-off state.
In one embodiment, the dc bus includes an anode power line connecting the anode of the high-voltage battery pack BAT and the positive power terminal of the load, and a cathode power line connecting the cathode of the high-voltage battery pack BAT and the negative power terminal of the load, the contactor circuit 10 includes an anode contactor K1 provided on the anode power line, and the input terminal of the contactor circuit 10 is the input terminal of the anode contactor K1.
In this embodiment, the first voltage acquisition circuit 20 and the second voltage acquisition circuit 30 are connected to the positive electrode of the high-voltage battery pack BAT, and respectively acquire the voltage of the input terminal of the positive electrode contactor K1 to the ground and the voltage of the high-voltage battery pack BAT, when the control circuit 50 receives a contactor control instruction, the positive electrode contactor K1 is controlled to be closed or opened, and the voltage of the input terminal of the positive electrode contactor K1 to the ground and the voltage of the high-voltage battery pack BAT are simultaneously acquired, when the variation of the voltage difference between the voltage of the input terminal of the positive electrode contactor K1 to the ground and the voltage at two ends of the high-voltage battery pack BAT exceeds a first preset voltage threshold, it is determined that the positive electrode contactor K1 circuit 10 successfully performs the switching operation, and if the voltage variation is at the first preset voltage threshold, it is indicated that the positive electrode contactor K1 is not closed or opened correctly, and a fault or.
Further, the contactor circuit 10 further comprises a negative contactor K2 arranged on a negative power line, and the negative contactor K2 is closed first and opened first when receiving a contactor control command;
the control circuit 50 is further configured to control the negative contactor K2 and the positive contactor K1 to sequentially perform a switching action after receiving the contactor control command, and determine whether the negative contactor K2 performs the switching action according to whether a variation of a voltage difference between the voltage to ground at the input terminal of the contactor circuit 10 and the voltage at the two ends of the high-voltage battery pack BAT exceeds a first preset voltage threshold.
In this embodiment, under the control of the control circuit 50, the negative contactor K2 and the positive contactor K1 are sequentially turned off or sequentially turned on, and simultaneously, before and after the switching state of the negative contactor K2 is controlled, the voltage acquired by the first voltage acquisition circuit 20 also changes, that is, when the negative contactor K2 is controlled to be switched from the off state to the on state, the voltage value thereof becomes large, when the positive contactor K1 is controlled to be switched from the off state to the on state, the voltage value thereof becomes small, the voltage acquired by the first voltage acquisition circuit 20 returns to the initial voltage, otherwise, when the negative contactor K2 is controlled to be switched from the on state to the off state, the voltage value thereof becomes small, when the positive contactor K1 is controlled to be switched from the on state to the off state, the voltage value thereof becomes large, the voltage acquired by the first voltage acquisition circuit 20 returns to the initial voltage, and the voltage variation of the voltage acquired by the positive contactor K1 according to the first voltage acquisition circuit 20 with respect to the voltage of the ground It is determined whether the negative contactor K2 and the positive contactor K1 sequentially perform the switching operation.
For example, when the negative contactor K2 is in the open state in the first initial state, the voltage collected by the first voltage collecting circuit 20 is 10V, the voltage collected by the second voltage collecting circuit 30 is 8V, and the relative voltage is 2V, then the negative contactor K2 performs switching action under the control of the control circuit 50, assuming that the first preset voltage threshold is 0-4V, when the voltage of the first voltage acquisition circuit 20 is detected to be 12V, and the relative voltage is 4V at this time, the voltage variation is 2V, within a first predetermined voltage threshold, it is an indication that the negative contactor K2 has not successfully performed a switching action, when the voltage of the first voltage acquisition circuit 20 is detected to be 15V, and the relative voltage is 7V, the voltage variation is 5V, outside the first predetermined voltage threshold, it indicates that the negative contactor K2 successfully performs the switching operation.
Meanwhile, when the voltage of the high voltage battery pack BAT changes due to charging and discharging, the acquired voltage values of the first voltage acquisition circuit 20 and the second voltage acquisition circuit 30 change simultaneously, and the relative voltages thereof remain unchanged in the same state, so that the first preset voltage threshold does not need to be reset and judged.
Further, the contactor circuit 10 further includes a pre-charging contactor K3 and a third voltage acquisition circuit 40, the contactor control command includes a contactor power-on command and a contactor power-off command, and the pre-charging contactor K3 is connected in parallel with the positive contactor K1;
a third voltage acquisition circuit 40 for acquiring a voltage of a power source terminal of the load;
the control circuit 50 is used for controlling the negative contactor K2 to pull in and controlling the pre-charging contactor K3 and the positive contactor K1 to pull in a staggered mode when a contactor power-on instruction is received, determining that the pre-charging contactor K3 successfully executes a switch switching action when the variation of the voltage difference value between the voltage of the input end of the positive contactor K1 to the ground and the voltage of the two ends of the high-voltage battery pack BAT exceeds a second preset voltage threshold value, and determining that the pre-charging contactor K3 executes a turn-off action and determining that the positive contactor K1 executes a pull-in action when the voltage difference between the voltage of the two ends of the high-voltage battery pack BAT and the voltage of the power end of the load control device is;
and when a contactor power-off command is received, controlling the negative contactor K2 and the positive contactor K1 to be sequentially disconnected, and judging whether the negative contactor K2 and the positive contactor K1 sequentially execute switch switching actions according to whether the variation of the voltage difference between the voltage of the input end of the contactor circuit 10 to the ground and the voltage of the two ends of the high-voltage battery pack BAT exceeds a first preset voltage threshold value.
In this embodiment, when receiving a power-on command of the contactor, the control circuit 50 controls the negative contactor K2 to be attracted first, and then controls the pre-charging contactor K3 to be attracted, and the impedance of the pre-charging contactor K3 is greater than that of the positive contactor K1, and a voltage dividing resistor may be externally connected to the negative contactor K2 or the pre-charging contactor K3 with a large impedance value may be selected to implement pre-start of a load, and after a preset time, the pre-charging contactor K3 is controlled to be disconnected and the positive contactor K1 is controlled to be attracted.
Meanwhile, when a contactor power-off command is received, the negative contactor K2 and the positive contactor K1 are controlled to be sequentially disconnected.
When a contactor power-on command is received, the switch state of the negative contactor K2 is kept unchanged, and is still judged according to whether the variation of the voltage difference between the voltage to ground at the input end of the positive contactor K1 and the voltage at the two ends of the high-voltage battery pack BAT exceeds a first preset voltage threshold, and the pull-in state of the pre-charging contactor K3 is also judged according to the variation of the voltage difference between the voltage to ground at the input end of the positive contactor K1 and the voltage at the two ends of the high-voltage battery pack BAT, because the impedance of the pre-charging contactor K3 is larger, the variation before and after closing is different from that of the positive contactor K1, a second preset voltage threshold is set to be compared and judged with the voltage variation, the second preset voltage threshold is larger than the first preset voltage threshold, and whether the pre-charging contactor K3 and the positive contactor K1 are sequentially and alternately opened and pulled in, and whether the difference of the voltage values collected by the second voltage collecting circuit 30 and the third voltage collecting circuit 40, when the voltage is within the preset voltage, the precharge contactor K3 is indicated to successfully perform the opening action, and the positive contactor K1 correctly performs the pull-in action.
When a contactor power-off instruction is received, whether the negative contactor K2 and the positive contactor K1 are sequentially disconnected is judged according to the variation of the voltage difference value between the voltage of the input end of the positive contactor K1 to the ground and the voltage of the two ends of the high-voltage battery pack BAT.
In one embodiment, as shown in fig. 2, the first voltage acquisition circuit 20 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and a first comparator IC 1;
a first end of the first resistor R1 is connected to the positive electrode of the battery pack, a second end of the first resistor R1, a first end of the second resistor R2, a first end of the first capacitor C1 and a non-inverting input end of the first comparator IC1 are interconnected, a second end of the second resistor R2 and a second end of the first capacitor C1 are all grounded, a first end of the third resistor R3 is grounded, a second end of the third resistor R3, an inverting input end of the first comparator IC1, a first end of the fourth resistor R4 and a first end of the second capacitor C2 are interconnected, and an output end of the first comparator IC1, a second end of the fourth resistor R4 and a second end of the second capacitor C2 are interconnected and a connection node is a signal end of the first voltage acquisition circuit 20.
As shown in fig. 3, the second voltage acquisition circuit 30 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a third capacitor C3, a fourth capacitor C4, and a second comparator IC 2;
a first end of the fifth resistor R5 is connected to the positive electrode of the battery pack, a second end of the fifth resistor R5, a first end of the sixth resistor R6, a first end of the third capacitor C3, and a non-inverting input terminal of the second comparator IC2 are interconnected, a second end of the sixth resistor R6 and a second end of the third capacitor C3 are all grounded, a first end of the seventh resistor R7 is connected to the negative electrode of the battery pack, a second end of the seventh resistor R7, an inverting input terminal of the second comparator IC2, a first end of the eighth resistor R8, and a first end of the fourth capacitor C4 are interconnected, an output end of the second comparator IC2, a second end of the eighth resistor R8, and a second end of the fourth capacitor C4 are interconnected, and a connection node is a signal end of the second voltage acquisition circuit 30.
In this embodiment, the resistor and the comparator in the first voltage acquisition circuit 20 divide the voltage of the input terminal of the positive contactor K1 to the ground voltage proportionally to obtain a first voltage signal, the resistor and the comparator in the second voltage acquisition circuit 30 divide the voltage of the high-voltage battery pack BAT to the ground voltage proportionally to obtain a second voltage signal, the ratio of the proportional division can be selected according to the requirement, for example, the voltage of the original high-voltage battery pack BAT is 200V, and 20V after the comparative division, the voltage of the input terminal of the original positive contactor K1 to the ground voltage is 180V when the negative contactor K2 is disconnected, and 18V after the proportional division, and the relative voltage of the two is-2V, when the negative contactor K2 performs the switch actuation, the voltage of the input terminal of the positive contactor K1 to the ground voltage is 24V after the proportional division, and the relative voltage is 4V, and the voltage variation is 6V, at this time, when the first preset voltage threshold is still 0-4V, the negative contactor K2 is indicated to successfully execute the switch switching action, otherwise, the first preset voltage threshold is abnormal.
As shown in fig. 1, the control circuit 50 includes a first voltage comparison circuit 51, a second voltage comparison circuit 52, a DSP processor 53, and a controller (not shown);
a first signal input end of the first voltage comparison circuit 51 is connected with a signal output end of the first voltage acquisition circuit 20, a second signal input end of the first voltage comparison circuit 51 is connected with a signal output end of the second voltage acquisition circuit 30, a first signal input end of the second voltage comparison circuit 52 is connected with a signal output end of the second voltage acquisition circuit 30, a second signal input end of the second voltage comparison circuit 52 is connected with a signal output end of the first voltage acquisition circuit 20, a signal output end of the second voltage acquisition circuit 30, a signal output end of the third voltage acquisition circuit 40, a signal output end of the first voltage comparison circuit 51 and a signal output end of the second voltage comparison circuit 52 are respectively connected with a signal input end of the DSP processor 53, a signal output end of the DSP processor 53 is connected with a signal end of the controller, the control end of the controller is also connected with the controlled end of each contactor respectively;
a first voltage comparison circuit 51 for comparing a voltage of an input terminal of the contactor circuit 10 to a ground voltage and a voltage of both terminals of the high voltage battery pack BAT, and outputting a first level signal to the DSP processor 53;
a second voltage comparison circuit 52 for comparing a voltage across the high-voltage battery pack BAT with a voltage to ground at the input terminal of the contactor circuit 10, and outputting a second level signal to the DSP processor 53;
the DSP 53 is used for determining whether each contactor executes corresponding switch switching action according to the first level signal, the second level signal and the voltage signal acquired by each voltage acquisition circuit, and feeding back the corresponding switch switching action to the controller;
and the controller is used for correspondingly controlling the execution switch switching action of each contactor according to the contactor control instruction, and carrying out power-on control and power-off control on the contactor circuit 10 of the load on-off control system according to the switch switching action of each contactor fed back by the DSP processor.
In this embodiment, the control circuit 50 compares the voltage to ground of the positive electrode contactor K1 with the voltage of the high-voltage battery pack BAT after proportional voltage division, and determines whether each contactor successfully performs a switching operation according to the level change.
For example, the voltage of the original high voltage battery pack BAT is 200V, 20V after comparative voltage division, the ground voltage at the input terminal of the original positive contactor K1 is 180V when the negative contactor K2 is turned off, 18V after proportional voltage division, the relative voltage of the two is-2V, at this time, the first voltage comparison circuit 51 outputs low level or high level, when the negative contactor K2 executes the switch pull-in action, the input terminal of the positive contactor K1 divides the ground voltage into 24V at a ratio, the relative voltage is 4V, the first voltage comparison circuit 51 outputs high level or low level, the level signal changes, which indicates that the negative contactor K2 successfully executes the pull-in action, the ratio of each proportion partial pressure can be correspondingly set according to different loads, and the requirement that the level signal changes when the switch state of the contactor is switched is only required to be met.
Similarly, before the actuation of the positive contactor K1, the second voltage comparison circuit 52 outputs a low level or a high level, when the voltage signal acquired by the first voltage acquisition circuit 20 is divided by a proportion and then restored to 18V, the second voltage comparison circuit 52 outputs a high level or a low level, which indicates that the positive contactor K1 successfully executes the switching action, and two voltage comparison circuits are arranged to respectively obtain the voltage variation before and after the switching of the positive contactor K1 and the negative contactor K2.
In one embodiment, as shown in fig. 4, the first voltage comparison circuit 51 includes a third comparator IC3, a non-inverting input terminal of the third comparator IC3 is connected to the signal output terminal of the first voltage acquisition circuit 20, an inverting input terminal of the third comparator IC3 is connected to the signal output terminal of the second voltage acquisition circuit 30, and an output terminal of the third comparator IC3 is connected to the signal input terminal of the DSP processor;
the second voltage comparison circuit 52 comprises a fourth comparator IC4, a non-inverting input terminal of the fourth comparator IC4 is connected with the signal output terminal of the second voltage acquisition circuit 30, an inverting input terminal of the fourth comparator IC4 is connected with the signal output terminal of the first voltage comparison circuit 51, and an output terminal of the fourth comparator IC4 is connected with the signal input terminal of the DSP processor.
In the present embodiment, the following switching operation is performed in response to a contactor control command.
(1) When the negative contactor K2 is not engaged, the voltage collected by the second voltage collecting circuit 30 and the voltage collected by the first voltage collecting circuit 20 are processed by the first voltage comparing circuit 51 and then output a high level, when only the negative contactor K2 is engaged, the output level of the first voltage comparing circuit 51 is inverted and changed into a low level, the DSP processor 53 detects the low level and determines the engagement of the negative contactor K2.
(2) After the actuation of the negative contactor K2 is completed, when the pre-charging contactor K3 is not actuated, the voltage collected by the second voltage collecting circuit 30 and the voltage collected by the first voltage collecting circuit 20 are processed by the second voltage comparing circuit 52 and then output a high level, after the pre-charging contactor K3 is actuated, the second voltage comparing circuit 52 outputs a level signal to turn over and become a low level, the DSP processor 53 detects the low level and judges the actuation of the pre-charging contactor K3.
(3) After the pre-charging contactor K3 finishes the pull-in, the positive contactor K1 is controlled to pull-in, the pre-charging contactor K3 is switched off, if the second voltage comparison circuit 52 marks and outputs a low level signal, and the voltage difference value between the voltage acquired by the first voltage acquisition circuit 20 and the voltage acquired by the third voltage acquisition circuit 40 is smaller than a preset voltage, for example, 2% of the voltage value of the high-voltage battery pack BAT, it can be determined that the positive contactor K1 finishes the pull-in, and the load is powered on.
(4) After each contactor disconnection of electric control under high voltage battery BAT, control circuit 50 initiatively discharges and discharges the electric charge of bus capacitance, when detecting through third voltage acquisition circuit 40 that there is voltage on the direct current bus, then judge that negative contactor K2 and anodal contactor K1 all can not break off, do not accomplish normally down the electricity, and adhesion appears simultaneously in anodal contactor K1 and negative contactor K2, and control circuit 50 sends out the warning this moment.
(5) The positive contactor K1 is normally opened, and the negative contactor K2 is stuck during system operation. When a contactor power-off instruction is received, the DSP processor 53 detects that the output level signal of the first voltage acquisition circuit 20 is a low level, determines that the negative contactor K2 is not disconnected, and sends an alarm signal when the power-off is abnormal.
(6) The negative contactor K2 is normally opened, and the positive contactor K1 is stuck during system operation. When a contactor power-off instruction is received, the DSP processor 53 detects that the output level signal of the second voltage comparison circuit 52 is a low level, determines that the positive contactor K1 is not disconnected, and sends an alarm signal when the power-off is abnormal.
And a level shift circuit, for example, a level shift circuit composed of a ninth resistor, a tenth resistor, an eleventh resistor and a switching tube Q1, may be further connected to the rear stages of the first voltage comparison circuit 51 and the second voltage comparison circuit 52, respectively, where the level shift circuit converts a high level into a low level and converts a low level into a high level, and performs signal amplification and isolation, thereby reducing signal interference and improving detection accuracy.
As shown in fig. 5, the present invention further provides a control method of a load on-off control system, which is used for the load on-off control system, and the control method of the load on-off control system includes:
when a contactor control instruction is received, controlling the contactor circuit 10 to act, and acquiring the voltage of an input end of the contactor circuit 10 to the ground voltage and the voltage of two ends of a high-voltage battery pack BAT;
when the variation of the voltage difference between the voltage of the input terminal to the ground of the contactor circuit 10 and the voltage of the two terminals of the high-voltage battery pack BAT exceeds a first preset voltage threshold, determining that the contactor circuit 10 successfully executes a switching action;
when the variation of the voltage difference between the input terminal-to-ground voltage of the contactor circuit 10 and the voltage across the high-voltage battery pack BAT is within the first preset voltage threshold, it is determined that the contactor circuit 10 has not successfully performed the switching action.
In this embodiment, when a contactor control command is received, the contactor circuit 10 is controlled to perform a switching operation, and the input terminal-to-ground voltage of the contactor circuit 10 and the voltage at both ends of the high voltage battery pack BAT are obtained, and it is determined whether the contactor circuit 10 performs the switching operation according to a variation of a voltage difference between the input terminal-to-ground voltage of the contactor circuit 10 and the voltage at both ends of the high voltage battery pack BAT, so as to determine whether the state of the contactor circuit 10 is good or abnormal, that is, the input terminal-to-ground voltage of the contactor circuit 10 is compared with the voltage at both ends of the high voltage battery pack BAT, and it is determined whether the variation of the voltage difference between the input terminal-to-ground voltage of the contactor circuit 10 and the voltage at both ends of the high voltage battery pack BAT is within a preset voltage threshold, and when the variation is within the preset voltage threshold, the adhesion or the trouble problem appear, when outside presetting the voltage threshold, then show that contactor circuit 10 correctly switches operating condition according to control signal, contactor circuit 10 is in normal operating condition, only need gather contactor circuit 10's input terminal to ground voltage and the voltage at high-voltage battery group BAT both ends respectively through two way acquisition circuit in this scheme, moreover, the steam generator is simple in structure, and regard high-voltage battery group BAT as the reference volume, contactor circuit 10's input terminal to ground voltage and the voltage at high-voltage battery group BAT both ends all keep dynamic change when the battery is full of electricity quantity and low-power, keep the relative voltage balance, it need not to follow the setting to preset the voltage threshold, the control degree of difficulty has been reduced, thereby improve accuracy and the reliability of detecting contactor on-off state.
The invention further provides an electric vehicle, which comprises a load on-off control system, the specific structure of the load on-off control system refers to the above embodiments, and the electric vehicle adopts all the technical schemes of all the embodiments, so that the electric vehicle at least has all the beneficial effects brought by the technical schemes of the above embodiments, and the detailed description is omitted, wherein the load on-off control system uses the control method of the load on-off control system.
The high-voltage battery pack supplies power to loads in the electric automobile, such as a motor, an air conditioner and the like, and judges whether a contactor in the load on-off control system correctly executes a switch switching action according to the control method of the load on-off control system, so that the working state of each contactor is determined, and the contactors can be found and processed in time when the contactor breaks down.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A load on-off control system, comprising:
the high-voltage battery pack is used for supplying power to a load through a direct-current bus;
the contactor circuit is arranged on the direct current bus and used for executing switch switching action when receiving a switch control signal;
the first voltage acquisition circuit is used for acquiring the voltage of an input end of the contactor circuit to the ground;
the second voltage acquisition circuit is used for acquiring the voltages at two ends of the high-voltage battery pack; and
the control circuit is used for controlling the action of the contactor circuit when receiving a contactor control command and acquiring the voltage of an input end of the contactor circuit to the ground voltage and the voltage of two ends of the high-voltage battery pack;
when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold, determining that the contactor circuit successfully executes a switch switching action;
and when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack is within a first preset voltage threshold, determining that the contactor circuit does not successfully execute the switching action.
2. The load on-off control system according to claim 1, wherein the dc bus comprises a positive power line connecting a positive terminal of the high voltage battery pack and a positive power terminal of the load, and a negative power line connecting a negative terminal of the high voltage battery pack and a negative power terminal of the load, the contactor circuit comprises a positive contactor provided on the positive power line, and an input terminal of the contactor circuit is an input terminal of the positive contactor.
3. The load on-off control system according to claim 2, wherein the contactor circuit further comprises a negative contactor disposed on the negative power line, the negative contactor being closed first and opened first when receiving the contactor control command;
the control circuit is further used for controlling the negative contactor and the positive contactor to sequentially execute switch switching actions after receiving a contactor control instruction, and judging whether the negative contactor executes the switch switching actions according to whether the variation of the voltage difference value between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold value.
4. The load on-off control system according to claim 2 or 3, wherein the contactor circuit further comprises a pre-charging contactor and a third voltage acquisition circuit, the contactor control command comprises a contactor power-on command and a contactor power-off command, and the pre-charging contactor is arranged in parallel with the positive contactor;
the third voltage acquisition circuit is used for acquiring the voltage of the power supply end of the load;
the control circuit is used for controlling the negative contactor to attract and controlling the pre-charging contactor and the positive contactor to attract in a staggered manner when a power-on instruction of the contactor is received, determining that the pre-charging contactor successfully executes a switch switching action when the variation of the voltage difference between the voltage of the input end of the positive contactor to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a second preset voltage threshold, and determining that the pre-charging contactor executes a turn-off action and determining that the positive contactor executes an attraction action when the voltage difference between the voltage of the two ends of the high-voltage battery pack and the voltage of the power end of the load control device is smaller than a preset voltage;
and when the contactor power-off instruction is received, controlling the negative contactor and the positive contactor to be sequentially disconnected, and judging whether the negative contactor and the positive contactor sequentially execute switch switching actions according to whether the variation of the voltage difference value between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold value.
5. The load on-off control system of claim 4, wherein the first voltage acquisition circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a first comparator;
the first end of the first resistor is connected with the positive pole of the battery pack, the second end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the positive phase input end of the first comparator are interconnected, the second end of the second resistor and the second end of the first capacitor are all grounded, the first end of the third resistor is grounded, the second end of the third resistor, the reverse phase input end of the first comparator, the first end of the fourth resistor and the first end of the second capacitor are interconnected, the output end of the first comparator, the second end of the fourth resistor and the second end of the second capacitor are interconnected, and a connection node is a signal end of the first voltage acquisition circuit.
6. The load on-off control system of claim 5, wherein the second voltage acquisition circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor, a fourth capacitor and a second comparator;
the first end of the fifth resistor is connected with the positive electrode of the battery pack, the second end of the fifth resistor, the first end of the sixth resistor, the first end of the third capacitor and the positive phase input end of the second comparator are interconnected, the second end of the sixth resistor and the second end of the third capacitor are both grounded, the first end of the seventh resistor is connected with the negative electrode of the battery pack, the second end of the seventh resistor, the negative phase input end of the second comparator, the first end of the eighth resistor and the first end of the fourth capacitor are interconnected, the output end of the second comparator, the second end of the eighth resistor and the second end of the fourth capacitor are interconnected, and the connection node is the signal end of the second voltage acquisition circuit.
7. The load on-off control system of claim 6, wherein the control circuit comprises a first voltage comparison circuit, a second voltage comparison circuit, a DSP processor and a controller;
the first signal input end of the first voltage comparison circuit is connected with the signal output end of the first voltage acquisition circuit, the second signal input end of the first voltage comparison circuit is connected with the signal output end of the second voltage acquisition circuit, the first signal input end of the second voltage comparison circuit is connected with the signal output end of the second voltage acquisition circuit, the second signal input end of the second voltage comparison circuit is connected with the signal output end of the first voltage acquisition circuit, the signal output end of the second voltage acquisition circuit, the signal output end of the third voltage acquisition circuit, the signal output end of the first voltage comparison circuit and the signal output end of the second voltage comparison circuit are respectively connected with the signal input end of the DSP processor, and the signal output end of the DSP processor is connected with the signal end of the controller, the control end of the controller is also connected with the controlled end of each contactor respectively;
the first voltage comparison circuit is used for comparing the voltage of the input end of the contactor circuit to the ground voltage and the voltage of the two ends of the high-voltage battery pack and outputting a first level signal to the DSP processor;
the second voltage comparison circuit is used for comparing the voltages at two ends of the high-voltage battery pack with the voltage of the input end of the contactor circuit to the ground voltage and outputting a second level signal to the DSP;
the DSP is used for determining whether each contactor executes corresponding switch switching action or not according to the first level signal, the second level signal and the voltage signal acquired by each voltage acquisition circuit, and feeding the corresponding switch switching action back to the controller;
and the controller is used for correspondingly controlling the execution switch switching action of each contactor according to the contactor control instruction, and carrying out power-on control and power-off control on the contactor circuit of the load on-off control system according to the switch switching action of each contactor fed back by the DSP processor.
8. The load on-off control system according to claim 7, wherein the first voltage comparison circuit comprises a third comparator, a non-inverting input terminal of the third comparator is connected to the signal output terminal of the first voltage acquisition circuit, an inverting input terminal of the third comparator is connected to the signal output terminal of the second voltage acquisition circuit, and an output terminal of the third comparator is connected to the signal input terminal of the DSP processor;
the second voltage comparison circuit comprises a fourth comparator, the positive phase input end of the fourth comparator is connected with the signal output end of the second voltage acquisition circuit, the negative phase input end of the fourth comparator is connected with the signal output end of the first voltage comparison circuit, and the output end of the fourth comparator is connected with the signal input end of the DSP processor.
9. A control method of a load on-off control system for the load on-off control system according to any one of claims 1 to 8, characterized in that the control method of the load on-off control system comprises:
when a contactor control command is received, controlling a contactor circuit to act, and acquiring voltage of an input end of the contactor circuit to earth voltage and voltage of two ends of a high-voltage battery pack;
when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack exceeds a first preset voltage threshold, determining that the contactor circuit successfully executes a switch switching action;
and when the voltage difference between the voltage of the input end of the contactor circuit to the ground and the voltage of the two ends of the high-voltage battery pack is within a first preset voltage threshold, determining that the contactor circuit does not successfully execute the switching action.
10. An electric vehicle comprising the load on-off control system according to any one of claims 1 to 8, wherein the load on-off control system uses the control method of the load on-off control system according to claim 9.
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