CN113246734A - Coil driving circuit for high-voltage relay on electric automobile - Google Patents
Coil driving circuit for high-voltage relay on electric automobile Download PDFInfo
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- CN113246734A CN113246734A CN202110642258.1A CN202110642258A CN113246734A CN 113246734 A CN113246734 A CN 113246734A CN 202110642258 A CN202110642258 A CN 202110642258A CN 113246734 A CN113246734 A CN 113246734A
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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
- 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
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Abstract
The invention relates to the technical field of electric control of electric automobiles, and discloses a coil driving circuit for a high-voltage relay on an electric automobile, aiming at the defects of the coil driving circuit adopting a high-side switch and a low-side switch as the high-voltage relay on the existing electric automobile controller, the coil driving circuit makes full use of the advantages of good optical coupling isolation effect, long service life, high transmission efficiency and strong load carrying capacity of a power relay, can be combined into a driving circuit form of the high-side switch and the low-side switch, seamlessly replaces a special high-side switch and a special low-side switch integrated chip, thoroughly solves the problems of heating loss and voltage drop on the existing high-voltage relay coil driving circuit, enhances the working stability and reliability of the high-voltage relay coil driving circuit, and has higher practical value.
Description
Technical Field
The invention relates to the technical field of electric control of electric automobiles, in particular to a coil driving circuit of a high-voltage relay for an electric automobile.
Background
The electric automobile is driven by electric power, a power source of the electric automobile is a high-voltage lithium battery pack, the energy of the high-voltage lithium battery pack is distributed to each power assembly on the whole automobile through a high-voltage distribution box (PDU), in order to guarantee the safety of the automobile and the safety of an electric system, a high-voltage relay needs to be configured between the high-voltage lithium battery pack and each power assembly, when the automobile is closed or breaks down, the high-voltage power source can be separated from each assembly system in time, and the effect of breaking a circuit is achieved. Therefore, the high voltage relay is an important safety device of the electric vehicle, and if the electric vehicle is not started, driven and stopped.
According to different vehicle types and specification configurations of power systems, the number of high-voltage relays used on the electric vehicle is different, for example: the high-voltage relay is controlled and driven by a Battery Management System (BMS), a Vehicle Control Unit (VCU) and a Motor Controller (MCU), the high-voltage relay has the working principle that a small voltage and a small current are used for controlling a large voltage and a large current, the high-voltage relay is internally divided into a coil control end and a load end, when a driving voltage is applied to the coil control end, the load end can be closed or disconnected, the normally-open high-voltage relay keeps the load end open when the driving voltage is not applied, and once the driving voltage is applied, the load end can be immediately closed, and a main loop is switched on; the normally closed high-voltage relay keeps the load terminal closed when no driving voltage is applied, and opens the load terminal immediately when the driving voltage is applied, thereby breaking the main circuit.
Therefore, whether the high-voltage relay can work safely and reliably and complete the specified action under the preset instruction completely depends on the driving circuit of the relay coil in the relevant controller.
At present, a coil of a high-voltage relay on an electric vehicle is driven by a special IC, the IC is divided into a high-side switch and a low-side switch, such as BTS723GW and TLE6228GP produced by Infineon (Infineon), the high-side switch is located between a power supply and a load and belongs to control positive, the low-side switch is located between the load and ground and belongs to control negative, when a high level and a low level are applied to a control pin of the driving IC, the high-voltage relay can be driven to be switched on and off, and as shown in fig. 1 and fig. 2, electrical control schematic diagrams of the high-side switch and the low-side switch are respectively shown.
The driving power supply of the controllers such as BMS, VCU and MCU on the electric automobile to the high-voltage relay coil is from a vehicle-mounted lead-acid storage battery, the rated output voltage of the lead-acid storage battery of a trolley is 12 Vdc, the fluctuation range of the working voltage is 10.5 Vdc-13.8 Vdc, the rated output voltage of the lead-acid storage battery of a cart is 24Vdc, and the fluctuation range of the working voltage is 19.2 Vdc-27.6 Vdc. When a corresponding control level is applied to an input pin of the drive IC, the power supply voltage VBAT + of the lead-acid battery can be applied to two ends of the coil through the high-side or low-side switch MOS tube, so that the load end contact of the high-voltage relay is driven to act. However, because of the existence of R between the drain and the source of the MOS tubeDS(on)On-resistance, such as high-side switch BTS723GW drain-source on-resistance R produced by InfineonDS(on)= 105m Ω, and a low-side switch TLE6228GP on-resistance between drain and source RDS(on)= 205m Ω, this on-resistance RDS(on)When the driving circuit works, the driving circuit generates heat and generates conduction voltage drop, so that the temperature rise of the driving chip is overhigh and potential safety hazards are generated, and particularly when the power supply voltage of the lead-acid battery is low, the conduction voltage drop of the switch MOS tube can further reduce the driving voltage finally applied to the two ends of the coil, so that the stability and the reliability of the coil driving are reduced.
Disclosure of Invention
The invention mainly aims to provide a coil driving circuit for a high-voltage relay on an electric automobile, which aims to thoroughly eliminate heating loss and voltage drop on the driving circuit and improve the working stability and reliability of the driving circuit.
In order to achieve the purpose, the coil driving circuit for the high-voltage relay on the electric automobile comprises a lead-acid storage battery, a controller power supply VCC, a self-recovery fuse F1, an input end A, an output end B, an output end C, an output end D, an output end E, a current-limiting resistor R1, a current-limiting resistor R2, a triode Q3, a freewheeling diode D1, a photoelectric coupler U1 and a power relay KM1, wherein a photosensitive diode VD and a detection triode VT which are in photoelectric induction connection are arranged in the photoelectric coupler U1, a coil end KL and a load contact KQ which are in magnetic coupling isolation are arranged in the power relay KM1, one end of the input end A, the current-limiting resistor R1, one end of the triode Q3, the current-limiting resistor R2 and one end of the photosensitive diode VD in the photoelectric coupler U1 are sequentially and electrically connected in series, the input end A is electrically connected with an I/O control pin on a CPU in the controller, the other end of the triode Q3 is electrically connected with the cathode of a controller power supply VCC, the other end of a photodiode VD in the optoelectronic coupler U1 is electrically connected with the anode of the controller power supply VCC, one end of a detection triode VT in the optoelectronic coupler U1 is electrically connected with one end of a coil end KL in the power relay KM1, the other end of the coil end KL in the power relay KM1 is electrically connected with the cathode of a lead-acid storage battery, the other end of the detection triode VT in the optoelectronic coupler U1 is electrically connected with the anode VBAT + of the lead-acid storage battery, a freewheeling diode D1 is connected in parallel at the two ends of the coil end KL in the power relay KM1 in the direction, an output end C and an output end D are respectively and electrically connected with the two ends of a load contact KQ in the power relay KM1, one end of the output end B is electrically connected with the self-recovery fuse F1 and the anode VBAT + of the lead-acid storage battery in series, one end of the output end E is electrically connected with the negative electrode of the lead-acid storage battery.
Further, when the high-side switch is used for driving output, the output end B and the output end C are electrically connected externally, and the output end D and the output end E are respectively electrically connected with two ends of a high-voltage relay coil to be controlled.
Further, when the output is driven by the low-side switch, the output end D and the output end E are electrically connected outside, and the output end B and the output end C are respectively electrically connected with two ends of a high-voltage relay coil to be controlled.
Further, the rated output voltage of the lead-acid storage battery is 12 Vdc or 24 Vdc.
Further, the output voltage of the controller power VCC is 5 Vdc or 3.3 Vdc.
Further, the transistor Q3 is an NPN transistor.
By adopting the technical scheme of the invention, the invention has the following beneficial effects: the technical scheme of the invention fully utilizes the advantages of good optical coupling isolation effect, long service life, high transmission efficiency and strong load carrying capacity of the power relay, can be combined into the drive circuit form of the high-side switch and the low-side switch, seamlessly replaces the special high-side switch and low-side switch integrated chip, thoroughly solves the problems of heating loss and voltage drop on the coil drive circuit of the existing high-voltage relay, enhances the working stability and reliability of the coil drive circuit of the high-voltage relay, and has higher practical value.
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 an electrical control schematic of a high-side switch;
FIG. 2 is an electrical control schematic of the low side switch;
fig. 3 is a schematic diagram of a coil driving circuit for a high voltage relay of an electric vehicle 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 all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides a coil driving circuit for a high-voltage relay on an electric automobile.
As shown in fig. 3, in an embodiment of the present invention, the coil driving circuit for a high voltage relay in an electric vehicle includes a lead-acid battery, a controller power VCC, a self-recovery fuse F1, an input terminal a, an output terminal B, an output terminal C, an output terminal D, an output terminal E, a current-limiting resistor R1, a current-limiting resistor R2, a triode Q3, a freewheeling diode D1, a photocoupler U1, and a power relay KM1, wherein a photodiode VD and a detection triode VT are disposed in the photocoupler U1, a coil terminal KL and a load contact KQ are disposed in the power relay KM1, the input terminal a, the current-limiting resistor R1, one end of the triode Q3, the current-limiting resistor R2, and one end of the photodiode VD in the photocoupler U1 are sequentially and electrically connected in series, the input terminal a is electrically connected to an I/O control pin on a CPU in the controller, the other end of the triode Q3 is electrically connected with the cathode of a controller power supply VCC, the other end of a photodiode VD in the optoelectronic coupler U1 is electrically connected with the anode of the controller power supply VCC, one end of a detection triode VT in the optoelectronic coupler U1 is electrically connected with one end of a coil end KL in the power relay KM1, the other end of the coil end KL in the power relay KM1 is electrically connected with the cathode of a lead-acid storage battery, the other end of the detection triode VT in the optoelectronic coupler U1 is electrically connected with the anode VBAT + of the lead-acid storage battery, a freewheeling diode D1 is connected in parallel at the two ends of the coil end KL in the power relay KM1 in the direction, an output end C and an output end D are respectively and electrically connected with the two ends of a load contact KQ in the power relay KM1, one end of the output end B is electrically connected with the self-recovery fuse F1 and the anode VBAT + of the lead-acid storage battery in series, one end of the output end E is electrically connected with the negative electrode of the lead-acid storage battery.
Specifically, the coil driving circuit of the high-voltage relay provided by the invention comprises an input control circuit and an output driving circuit, and a photoelectric coupler U1 (optical coupler) is taken as a boundary line, wherein the left half part of the optical coupler belongs to the input control circuit part, and the right half part of the optical coupler belongs to the output driving circuit part. The optocoupler is a current type device, and is a device for transmitting an electric signal by taking light as a medium, a photosensitive diode is arranged on the left side in the device, a detection triode is arranged on the right side in the device, when a trigger circuit forms a loop to work, the photosensitive diode can emit light due to current passing, the detection triode can be conducted after receiving the optical signal, and a power relay coil is electrified so as to drive a load contact to act.
In the coil driving circuit shown in fig. 3, the input control circuit part is supplied with a working power supply by a controller (BMS, VCU and MCU), the output driving circuit part is supplied with power by a vehicle-mounted lead-acid battery, and the two parts of power supplies can be electrically isolated according to specific conditions and can also be connected in a single-point grounding manner to improve the anti-interference capability of the circuit. The input end A is connected to an I/O control pin on a CPU in the controller and is directly driven and controlled by the CPU, the output end B, the output end C, the output end D and the output end E are external output contacts of a coil driving circuit and can be matched according to the requirements of customers, when the output end B is used as a high-side switch for driving and outputting, the output end B and the output end C are directly connected together in a short mode externally, and the output end D and the output end E are respectively connected to two ends of a high-voltage relay coil to be controlled; when the high-voltage relay is used as a low-side switch drive output, the output end D and the output end E are directly connected together in a short circuit mode on the outside, and the output end B and the output end C are respectively connected to two ends of a high-voltage relay coil to be controlled.
VBAT + is led out from the positive pole of the lead-acid battery, and provides a 12 Vdc or 24Vdc working power supply for the output driving part, and meanwhile, the control voltage of a coil of the power relay is matched with the rated output voltage of the lead-acid battery when the specification and the model of the power relay are selected; VCC is the power supply on the controllers (BMS, VCU and MCU), typically a 5 Vdc or 3.3 Vdc voltage platform;
r1 is the base current-limiting resistor of NPN type triode Q3, Q3 is used for controlling the make-and-break of photosensitive diode VD in the optocoupler U1, R2 is the current-limiting resistor of photosensitive diode VD, its function is to guarantee that the current entering photosensitive diode VD in the optocoupler U1 can trigger the detection triode VT to conduct, will not exceed the maximum current that photosensitive diode VD can bear again; d1 is a freewheeling diode, is reversely connected in parallel at two ends of a coil KL of the relay KM1, and is used for providing a backflow path for induced electromotive force generated when the coil is open-circuited, absorbing instant induced energy and preventing instant high-voltage heavy current from damaging the optical coupler chip; KM1 is power relay, divide into coil end KL and load contact KQ, and two parts are separated through the magnetic coupling, and the normally open contact of load contact KQ is used for constituting the control output of high limit switch and low limit switch.
Specifically, when a high level is applied to an input end A, a triode Q3 is conducted, so that a photodiode VD loop in a drive optocoupler U1 is conducted, the photodiode VD emits light through current, a detection triode VT is conducted after receiving an optical signal, a lead-acid storage battery power supply is applied to two ends of a coil KL of a power relay KM1 through the detection triode VT, and the coil KL generates magnetic force to attract a load contact KQ armature to act after being electrified, so that a high-side switch or a low-side switch is switched on to drive output; when a low level is applied to the input end A, the triode Q3 is turned off, so that a loop of a photodiode VD in the optocoupler U1 is disconnected, the photodiode VD cannot emit light because no current passes through the photodiode VD, the detection triode VT is in a disconnected state, and two ends of a coil end KL of the power relay KM1 naturally have no control voltage, so that a load contact KQ armature can be released to be disconnected, and then the driving output of the high-side switch or the low-side switch can be released to be disconnected.
Specifically, the invention fully utilizes the advantages of good optical coupling isolation effect, long service life, high transmission efficiency and strong load carrying capacity of a power relay aiming at the defects of a coil driving circuit of a high-voltage relay which adopts a high-side switch and a low-side switch on the conventional electric automobile controller, can be combined into a driving circuit form of the high-side switch and the low-side switch, seamlessly replaces a special high-side switch and a special low-side switch integrated chip, thoroughly solves the problems of heating loss and voltage drop on the conventional coil driving circuit of the high-voltage relay, enhances the working stability and reliability of the coil driving circuit of the high-voltage relay, and has higher practical value.
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 (6)
1. A coil driving circuit for a high-voltage relay on an electric automobile is characterized by comprising a lead-acid storage battery, a controller power VCC, a self-recovery fuse F1, an input end A, an output end B, an output end C, an output end D, an output end E, a current-limiting resistor R1, a current-limiting resistor R2, a triode Q3, a freewheeling diode D1, a photoelectric coupler U1 and a power relay KM1, wherein a photosensitive diode VD and a detection triode VT which are in photoelectric induction connection are arranged in the photoelectric coupler U1, a coil end KL and a load contact KQ which are in magnetic coupling isolation are arranged in the power relay KM1, one end of the input end A, the current-limiting resistor R1, one end of the triode Q3, the current-limiting resistor R2 and one end of the photosensitive diode VD in the photoelectric coupler U1 are sequentially and electrically connected in series, the input end A is electrically connected with an I/O control pin on a CPU in the controller, and the other end of the triode Q3 is electrically connected with a cathode of the controller power VCC, the other end of a photosensitive diode VD in the photoelectric coupler U1 is electrically connected with the anode of a controller power supply VCC, one end of a detection triode VT in the photoelectric coupler U1 is electrically connected with one end of a coil end KL in the power relay KM1, the other end of the coil end KL in the power relay KM1 is electrically connected with the cathode of a lead-acid battery cell, the other end of the detection triode VT in the photoelectric coupler U1 is electrically connected with the positive pole VBAT + of the lead-acid battery jar, the direction of the freewheeling diode D1 is connected in parallel with two ends of the coil end KL in the power relay KM1, the output terminal C and the output terminal D are electrically connected to both ends of a load contact KQ in the power relay KM1, one end of the output end B is electrically connected with the self-recovery fuse F1 and the positive electrode VBAT + of the lead-acid storage battery in series, and one end of the output end E is electrically connected with the negative electrode of the lead-acid storage battery.
2. The coil driving circuit for a high voltage relay on an electric vehicle according to claim 1, wherein the output terminal B and the output terminal C are electrically connected externally when being a high side switch driving output, and the output terminal D and the output terminal E are electrically connected to both ends of a coil of the high voltage relay to be controlled, respectively.
3. The coil driving circuit for a high voltage relay on an electric vehicle according to claim 1, wherein the output terminal D and the output terminal E are electrically connected externally when being a low side switch driving output, and the output terminal B and the output terminal C are electrically connected to both ends of a coil of the high voltage relay to be controlled, respectively.
4. The coil driving circuit for the high voltage relay on the electric vehicle as claimed in claim 1, wherein the rated output voltage of the lead-acid battery is 12 Vdc or 24 Vdc.
5. The coil driving circuit for a high voltage relay on an electric vehicle according to claim 1, wherein the output voltage of the controller power source VCC is 5 Vdc or 3.3 Vdc.
6. The coil driving circuit for the high voltage relay on the electric vehicle as claimed in claim 1, wherein the transistor Q3 is an NPN transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110642258.1A CN113246734A (en) | 2021-06-09 | 2021-06-09 | Coil driving circuit for high-voltage relay on electric automobile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110642258.1A CN113246734A (en) | 2021-06-09 | 2021-06-09 | Coil driving circuit for high-voltage relay on electric automobile |
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| Publication Number | Publication Date |
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| CN113246734A true CN113246734A (en) | 2021-08-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110642258.1A Pending CN113246734A (en) | 2021-06-09 | 2021-06-09 | Coil driving circuit for high-voltage relay on electric automobile |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114851909A (en) * | 2022-04-20 | 2022-08-05 | 潍柴动力股份有限公司 | Control method and device for electric vehicle and computer readable storage medium |
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2021
- 2021-06-09 CN CN202110642258.1A patent/CN113246734A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114851909A (en) * | 2022-04-20 | 2022-08-05 | 潍柴动力股份有限公司 | Control method and device for electric vehicle and computer readable storage medium |
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