CN115078813B - Circuit and method for detecting insulation resistance and total voltage of energy storage BMS - Google Patents
Circuit and method for detecting insulation resistance and total voltage of energy storage BMS Download PDFInfo
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- 238000005070 sampling Methods 0.000 claims description 170
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Abstract
The invention discloses a circuit and a method for detecting insulation resistance and total voltage of an energy storage BMS, and relates to the technical field of BMS battery system detection. The invention is provided with the front-end total voltage detection circuit, the rear-end total voltage detection circuit and the insulation resistance detection circuit in a set of circuits, and can realize three functions of insulation resistance detection, battery-end total voltage detection and grid-connected end/load end total voltage detection by changing the circuit topology through the switch, thereby effectively reducing the volume and the weight of BMS plates, reducing the use of devices and lowering the cost on the premise of realizing rapid and accurate detection of required data; the insulation resistance value and the total voltage value of the front end and the rear end can be immediately obtained when the fault occurs, so that the accident of personal and property safety loss caused by the damage of the system due to the insulation electric leakage or the too low/too high total voltage is prevented.
Description
Technical Field
The invention relates to the technical field of BMS battery system detection, in particular to a circuit and a method for detecting insulation resistance and total voltage of an energy storage BMS.
Background
In order to meet the 'carbon peak' and 'carbon neutralization' strategic targets of corresponding national calls, construction and operation of domestic electrochemical energy storage power stations are in a high-speed growing development stage. Because of the large number of cells, large scale and complex system in electrochemical energy storage power stations, high requirements are placed on the safety and reliability of the system operation. The BMS is used as the brain of the battery system and is responsible for monitoring the running condition of the battery system and guaranteeing the safe and stable running of the system, wherein the detection of the insulation resistance of a port of the battery system and the detection of the total voltage at two ends of the high-voltage box are particularly critical.
In the prior art, the patent with the publication number of CN212992038U discloses an energy storage power station battery management system containing an independent insulation monitoring device, an insulation monitoring main control unit is connected with a monitoring slave control unit in a communication way, a measuring interface of the insulation monitoring main control unit is connected with a direct current bus bar, a communication interface of the insulation monitoring main control unit is connected with a primary control unit through an RS485 interface, a measuring interface of the insulation monitoring slave control unit is connected with a corresponding positive terminal and a negative terminal of a battery cluster in a high-voltage direct current box, the primary control unit and a plurality of secondary control units are networked through a CAN bus, each control unit and a plurality of tertiary control units are networked through the CAN bus, and the primary control unit is connected with an energy storage power station monitoring and energy management system through an Ethernet interface and is connected with an energy storage converter control system corresponding to the battery system through an RS485 interface and a dry contact. The battery management system of the energy storage power station with the independent insulation monitoring device provided by the utility model can improve the on-line monitoring capability of the energy storage power station BMS on the insulation state of the battery system.
The battery management system of the energy storage power station provided by the patent can not detect the insulation resistance value of a battery system port and the voltages at two ends of the high-voltage box at the same time, and when a fault occurs, the system is damaged due to insulation electric leakage or too low/too high total voltage, so that personal and property safety loss is caused; meanwhile, the device has more components, larger occupied space and higher manufacturing cost.
Therefore, a circuit and a method for detecting insulation resistance and total voltage of an energy storage BMS are needed, which can detect the insulation resistance of a battery system port and the total voltage at two ends of a high-voltage box, can immediately obtain the insulation resistance value and the total voltage value at the front end and the rear end when a fault occurs, and prevent damage to a system due to insulation leakage or over-low/over-high total voltage and cause personal and property safety loss; meanwhile, certain branches are shared by switching of a switch in a set of circuit, so that the number of components is reduced, and the space and the manufacturing cost of a hardware circuit are saved.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention discloses a circuit and a method for detecting the insulation resistance and the total voltage of an energy storage BMS, and aims to solve the problems that the insulation resistance value of a battery system port and the voltages at two ends of a high-voltage box cannot be detected simultaneously in the prior art, and when faults occur, the system is damaged due to insulation leakage or over-low/over-high total voltage, so that personal and property safety is lost; and the components are more, the occupied space is larger, and the manufacturing cost is higher.
In order to achieve the above purpose, the present invention adopts the technical scheme that:
The circuit for detecting the insulation resistance and the total voltage of the energy storage BMS comprises a sampling unit, a front-end positive voltage dividing unit, a front-end negative voltage dividing unit, a rear-end positive voltage dividing unit, a rear-end negative voltage dividing unit and a grounding unit;
The sampling unit comprises an anode sampling resistor, a cathode sampling resistor and a sampling module, wherein the anode sampling resistor and the cathode sampling resistor are connected in series, the sampling module is respectively connected in parallel with two ends of the anode sampling resistor and the cathode sampling resistor, and the voltages of the two ends of the anode sampling resistor and the cathode sampling resistor are collected;
The front-end positive voltage dividing unit is connected with the positive sampling resistor and comprises a plurality of front-end positive voltage dividing resistors connected in series and a first switch for controlling the on-off of the front-end positive voltage dividing unit; the front-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor and comprises a plurality of front-end negative electrode voltage dividing resistors connected in series and a second switch for controlling the on-off of the front-end negative electrode voltage dividing unit; the front-end positive voltage dividing unit, the sampling unit and the front-end negative voltage dividing unit are sequentially connected in series to form a front-end total voltage detection circuit;
The rear end positive voltage dividing unit is connected with the positive sampling resistor and is connected with the front end positive voltage dividing unit in parallel, and the rear end positive voltage dividing unit comprises a plurality of rear end positive voltage dividing resistors connected in series and a third switch for controlling the on-off of the rear end positive voltage dividing unit; the rear-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor and is connected with the front-end negative electrode voltage dividing unit in parallel, and the rear-end negative electrode voltage dividing unit comprises a plurality of rear-end negative electrode voltage dividing resistors connected in series and a fifth switch for controlling the on-off of the rear-end negative electrode voltage dividing unit; the rear end positive voltage dividing unit, the sampling unit and the rear end negative voltage dividing unit are sequentially connected in series to form a rear end total voltage detection circuit;
The grounding unit is connected to a line of the series connection of the positive sampling resistor and the negative sampling resistor, and comprises a fourth switch for controlling the on-off of the grounding unit; the front end positive electrode voltage division unit, the positive electrode sampling resistor and the grounding unit are sequentially connected in series to form a positive electrode insulation resistor detection circuit, and the front end negative electrode voltage division unit, the negative electrode sampling resistor and the grounding unit are sequentially connected in series to form a negative electrode insulation resistor detection circuit.
In the invention, a front-end positive electrode voltage dividing unit and a front-end negative electrode voltage dividing unit are respectively connected with the positive electrode and the negative electrode at the joint of the battery and the high-voltage box so as to detect the total voltage of the battery end at the front end; the rear positive voltage dividing unit and the rear negative voltage dividing unit are respectively connected with the positive and negative electrodes at the joint of the load end (or grid-connected end) and the high-voltage box so as to detect the total voltage of the grid-connected end/the load end of the rear end; the grounding unit is grounded and used for detecting the insulation resistance of the anode and the cathode of the battery system to the ground.
The rear positive voltage dividing unit and the rear negative voltage dividing unit are connected with a load end or a grid-connected end, and the load end and the grid-connected end are alternatively connected, when the rear end (output end) of the high-voltage box of the battery system is connected with a load, the rear end is directly connected with electric equipment, and when the rear end is connected with the grid-connected end, the rear end is connected with a transformer and then connected with a power grid, so that the power can be transmitted to the power grid or the power grid can charge the battery system.
The front-end positive voltage dividing unit, the sampling unit and the front-end negative voltage dividing unit are sequentially connected in series to form a front-end total voltage detection circuit, when the battery-end total voltage is detected, the first switch and the second switch are closed, the front-end positive voltage dividing unit, the sampling unit and the front-end negative voltage dividing unit are communicated, the voltages of the positive sampling resistor and the negative sampling resistor are collected through the sampling module, and then the battery-end total voltage is calculated.
The rear positive voltage dividing unit, the sampling unit and the rear negative voltage dividing unit are sequentially connected in series to form a rear total voltage detection circuit, when the load end/grid-connected end total voltage is detected, the third switch and the fifth switch are closed, so that the rear positive voltage dividing unit, the sampling unit and the rear negative voltage dividing unit are communicated, the voltages of the positive sampling resistor and the negative sampling resistor are collected through the sampling module, and then the load end or the grid-connected end total voltage is obtained through calculation.
The front end positive pole voltage dividing unit, the positive pole sampling resistor and the grounding unit are sequentially connected in series to form a positive pole insulation resistor detection circuit, the front end negative pole voltage dividing unit, the negative pole sampling resistor and the grounding unit are sequentially connected in series to form a negative pole insulation resistor detection circuit, when the resistance value of the insulation resistor is detected, the first switch, the second switch and the fourth switch are sequentially closed according to the setting, the front end positive pole voltage dividing unit, the positive pole sampling resistor and the grounding unit are communicated, the front end negative pole voltage dividing unit, the negative pole sampling resistor and the grounding unit are communicated, the voltage of the positive pole sampling resistor and the voltage of the negative pole sampling resistor are collected through the sampling module, and then the resistance value of the insulation resistor is calculated.
Further, the positive sampling resistor is connected with a third resistor in series, and the negative sampling resistor is connected with a sixth resistor in series. In the invention, the third resistor and the sixth resistor are shared large resistors, and are used when detecting the total voltage of the battery end at the front end and the load end (or grid-connected end) at the rear end, so as to avoid the problem of cost increase caused by separately setting the resistors.
Further, the front-end positive voltage dividing resistor comprises a first resistor and a second resistor, and the first resistor, the first switch and the second resistor are sequentially connected in series. The first resistor and the second resistor have the functions of dividing the total voltage of the battery into small voltages, inputting the small voltages into the sampling module for detection, and the first switch has the function of controlling the on-off of the front-end positive voltage dividing unit.
Further, the front-end negative voltage dividing resistor comprises a seventh resistor and an eighth resistor, and the seventh resistor, the second switch and the eighth resistor are sequentially connected in series. The seventh resistor and the eighth resistor have the functions of dividing the total voltage of the battery into small voltages, inputting the small voltages into the sampling module for detection, and the second switch has the function of controlling the on-off of the front-end negative electrode voltage dividing unit.
Further, the rear-end positive voltage dividing resistor comprises a ninth resistor and a tenth resistor, and the ninth resistor, the third switch and the tenth resistor are sequentially connected in series. The ninth resistor and the tenth resistor are used for dividing the total voltage of the load end/grid-connected end into small voltage, inputting the small voltage into the sampling module for detection, and the third switch is used for controlling the on-off of the rear-end positive voltage dividing unit.
Further, the rear-end negative voltage dividing resistor comprises an eleventh resistor and a twelfth resistor, and the eleventh resistor, the fifth switch and the twelfth resistor are sequentially connected in series. The eleventh resistor and the twelfth resistor are used for dividing the total voltage of the load end/grid-connected end into small voltage, inputting the small voltage into the sampling module for detection, and the fifth switch is used for controlling the on-off of the rear-end negative electrode voltage dividing unit.
Preferably, the rear-end positive voltage dividing unit and the rear-end negative voltage dividing unit are respectively connected with a first diode and a second diode in series, and the trend of the loop is limited by utilizing the unidirectional conductivity of the diodes.
Based on the circuit, the invention also provides a method for detecting the insulation resistance and the total voltage of the energy storage BMS, which comprises a total detection circuit connection step, a front-end total voltage detection step, a rear-end total voltage detection step and an insulation resistance detection step;
The general detection circuit is grounded, the front end of the general detection circuit is connected to the connection part of the battery and the high-voltage box, and the rear end of the general detection circuit is connected to the connection part of the load end/grid-connected end and the high-voltage box; the total detection circuit comprises a sampling unit, a front-end positive electrode voltage division unit, a front-end negative electrode voltage division unit, a rear-end positive electrode voltage division unit, a rear-end negative electrode voltage division unit and a grounding unit;
the front-end total voltage detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive voltage division unit, the sampling unit and the front-end negative voltage division unit to form a front-end total voltage detection circuit, collect voltages at two ends of the current passing through the sampling unit, and obtain front-end total voltage according to the collected voltages at the two ends;
The method comprises a back-end total voltage detection step, wherein a switch of a total detection circuit is controlled to enable current to sequentially pass through a back-end positive electrode voltage division unit, a sampling unit and a back-end negative electrode voltage division unit to form a back-end total voltage detection circuit, the sampling unit is used for collecting voltages at two ends of the current passing through, and then the back-end total voltage is obtained according to the collected voltages at the two ends;
and the insulation resistance detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive electrode voltage division unit, the sampling unit and the grounding unit respectively, form an insulation resistance detection circuit, collect the voltages of two ends through which the current passes by the sampling unit, and obtain the insulation resistance value of the positive electrode and the negative electrode of the battery system to the ground according to the collected voltages of the two ends and the front-end total voltage obtained in the front-end total voltage detection step.
Further, in the step of detecting the front end total voltage, when the front end total voltage is detected, the first switch and the second switch of the total detection circuit are closed, the third switch, the fourth switch and the fifth switch of the total detection circuit are turned off, the front end total voltage detection circuit is communicated, the sampling module is used for collecting the total voltages V 1 at two ends of the positive electrode sampling resistor and the negative electrode sampling resistor, and the front end total voltage V Front is obtained:
，
Wherein, R 1 is a first resistor, R 2 is a second resistor, R 3 is a third resistor, R 4 is a positive sampling resistor, R 5 is a negative sampling resistor, R 6 is a sixth resistor, R 7 is a seventh resistor, and R 8 is an eighth resistor.
Further, in the step of detecting the total voltage of the rear end, when the total voltage of the rear end is detected, a third switch and a fifth switch of the total detection circuit are closed, a first switch, a second switch and a fourth switch of the total detection circuit are turned off, the total voltage detection circuit of the rear end is communicated, and a sampling module is used for collecting the total voltages V 2 of two ends of a positive electrode sampling resistor and a negative electrode sampling resistor, so that the total voltage V Back of the rear end is obtained:
，
Wherein R 3 is a third resistor, R 4 is a positive sampling resistor, R 5 is a negative sampling resistor, R 6 is a sixth resistor, R 9 is a ninth resistor, R 10 is a tenth resistor, R 11 is an eleventh resistor, and R 12 is a twelfth resistor.
Further, in the insulation resistance detection, when the insulation resistance value is detected, the method includes the following steps:
a. closing a first switch and a fourth switch of a total detection circuit, turning off a second switch, a third switch and a fifth switch of the total detection circuit, communicating an anode insulation resistance detection circuit, collecting voltage V 3 at two ends of an anode sampling resistor by using a sampling module, and obtaining voltage V x at two ends of a battery system anode insulation resistance R x to ground:
，
in the middle of ,R1+R2+R3= R6+R7+R8=Ra,R4=R5=Rb;
B. Closing a second switch and a fourth switch of the total detection circuit, turning off a first switch, a third switch and a fifth switch of the total detection circuit, communicating the negative insulation resistance detection circuit, collecting the voltage V 4 at two ends of a negative sampling resistor by using a sampling module, and obtaining the voltage V y at two ends of a battery system negative insulation resistance R y:
，
c. The front end total voltage V Front, the two-end voltage V 3 of the positive electrode sampling resistor, the two-end voltage V 4 of the negative electrode sampling resistor, the two-end voltage V x of the battery system positive electrode ground insulation resistor R x and the two-end voltage V y of the battery system negative electrode ground insulation resistor R y obtained in the front end total voltage detection step are utilized to obtain the resistance values of the battery system positive electrode ground insulation resistor R x and the battery system negative electrode ground insulation resistor R y:
。
the invention has the beneficial effects that:
According to the circuit and the method provided by the invention, the front-end total voltage detection circuit, the rear-end total voltage detection circuit and the insulation resistance detection circuit are arranged in one set of circuit, and the three functions of insulation resistance detection, battery-end total voltage detection and grid-connected end/load-end total voltage detection can be realized by changing the circuit topology through the switch, so that on the premise of realizing rapid and accurate detection of required data, certain branches are shared, the volume and the weight of BMS plates can be effectively reduced, the use of devices is reduced, and the cost is reduced.
The circuit and the method provided by the invention can immediately obtain the insulation resistance value and the total voltage value of the front end and the rear end when a fault occurs, and prevent accidents of personal and property safety loss caused by damage to a system due to insulation electric leakage or too low/too high total voltage.
Drawings
FIG. 1 is a general detection circuit topology of the present invention;
FIG. 2 is a circuit topology within the high voltage tank of the present invention;
FIG. 3 is a front end total voltage equivalent detection circuit of the present invention;
FIG. 4 is a back-end total voltage equivalent detection circuit of the present invention;
fig. 5 shows the principle of insulation resistance detection according to the present invention.
Reference numerals:
In the figure: 1. a sampling module; r 1, a first resistor; r 2, a second resistor; r 3 and a third resistor; r 4, positive electrode sampling resistor; r 5 and a negative electrode sampling resistor; r 6, a sixth resistor; r 7, seventh resistor; r 8 and an eighth resistor; r 9, ninth resistor; r 10, tenth resistor; r 11, eleventh resistor; r 12, twelfth resistor; k 1, first switch; k 2, a second switch; k 3, third switch; k 4, fourth switch; d 1, first diode; d 2, a second diode.
Detailed Description
The conception, specific structure, and technical effects produced by the present invention will be clearly and completely described below with reference to the embodiments and the drawings to fully understand the objects, features, and effects of the present invention.
Example 1
A circuit for energy storage BMS insulation resistance and total voltage detection, as shown in figure 1, includes sampling unit, front end positive pole voltage division unit, front end negative pole voltage division unit, rear end positive pole voltage division unit, rear end negative pole voltage division unit and to ground unit.
The sampling unit comprises an anode sampling resistor R 4, a cathode sampling resistor R 5 and a sampling module 1, wherein the anode sampling resistor R 4 and the cathode sampling resistor R 5 are connected in series, the sampling module is respectively connected in parallel with two ends of the anode sampling resistor R 4 and the cathode sampling resistor R 5, and the voltages at two ends of the anode sampling resistor R 4 and the cathode sampling resistor R 5 are collected. In this embodiment, the sampling module 1 is the ADS in fig. 1, that is, the AD sampling chip.
The front-end positive voltage dividing unit is connected with the positive sampling resistor R 4 and comprises a plurality of front-end positive voltage dividing resistors connected in series and a first switch K 1 for controlling the on-off of the front-end positive voltage dividing unit; the front-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor R 5 and comprises a plurality of front-end negative electrode voltage dividing resistors connected in series and a second switch K 2 for controlling the on-off of the front-end negative electrode voltage dividing unit; the front end positive voltage dividing unit, the sampling unit and the front end negative voltage dividing unit are sequentially connected in series to form a front end total voltage detection circuit. When the front end total voltage is detected, the first switch K 1 and the second switch K 2 are closed, so that the front end positive voltage dividing unit, the sampling unit and the front end negative voltage dividing unit are communicated, the voltages of the positive sampling resistor R 4 and the negative sampling resistor R 5 are collected through the sampling module, and the front end total voltage is obtained through calculation.
The rear-end positive voltage dividing unit is connected with the positive sampling resistor R 4 and is connected with the front-end positive voltage dividing unit in parallel, and comprises a plurality of rear-end positive voltage dividing resistors connected in series and a third switch K 3 for controlling the on-off of the rear-end positive voltage dividing unit; the rear-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor R 5 and is connected with the front-end negative electrode voltage dividing unit in parallel, and comprises a plurality of rear-end negative electrode voltage dividing resistors connected in series and a fifth switch K 5 for controlling the on-off of the rear-end negative electrode voltage dividing unit; the rear end positive voltage dividing unit, the sampling unit and the rear end negative voltage dividing unit are sequentially connected in series to form a rear end total voltage detection circuit. When the total voltage of the rear end is detected, the third switch K 3 and the fifth switch K 5 are closed, so that the positive voltage dividing unit of the rear end, the sampling unit and the negative voltage dividing unit of the rear end are communicated, the voltages of the positive sampling resistor R 4 and the negative sampling resistor R 5 are collected through the sampling module, and the total voltage of the rear end is calculated.
The grounding unit is connected to a line of the positive sampling resistor R 4 and the negative sampling resistor R 5 which are connected in series, and comprises a fourth switch K 4 for controlling the on-off of the grounding unit; the front end positive electrode voltage division unit, the positive electrode sampling resistor R 4 and the grounding unit are sequentially connected in series to form a positive electrode insulation resistance detection circuit, and the front end negative electrode voltage division unit, the negative electrode sampling resistor R 5 and the grounding unit are sequentially connected in series to form a negative electrode insulation resistance detection circuit. When the resistance value of the insulation resistor is detected, the first switch K 1, the second switch K 2 and the fourth switch K 4 are sequentially closed according to the setting, so that the front positive electrode voltage dividing unit, the positive electrode sampling resistor R 4 and the grounding unit are communicated, the front negative electrode voltage dividing unit, the negative electrode sampling resistor R 5 and the grounding unit are communicated, the voltages of the positive electrode sampling resistor R 4 and the negative electrode sampling resistor R 5 are collected through the sampling module, and the resistance value of the insulation resistor is calculated.
Example 2
This embodiment is a further improvement on the basis of embodiment 1, as shown in fig. 1, the positive sampling resistor R 4 is connected in series with a third resistor R 3, and the negative sampling resistor R 5 is connected in series with a sixth resistor R 6.
The front-end positive voltage dividing resistor comprises a first resistor R 1 and a second resistor R 2, and the first resistor R 1, a first switch K 1 and the second resistor R 2 are sequentially connected in series; the front-end negative voltage dividing resistor comprises a seventh resistor R 7 and an eighth resistor R 8, and the seventh resistor R 7, the second switch K 2 and the eighth resistor R 8 are sequentially connected in series.
The rear-end positive voltage dividing resistor comprises a ninth resistor R 9 and a tenth resistor R 10, and the ninth resistor R 9, the third switch K 3 and the tenth resistor R 10 are sequentially connected in series; the rear-end negative voltage dividing resistor comprises an eleventh resistor R 11 and a twelfth resistor R 12, and the eleventh resistor R 11, the fifth switch K 5 and the twelfth resistor R 12 are sequentially connected in series. The rear-end positive electrode voltage dividing unit and the rear-end negative electrode voltage dividing unit are respectively connected with a first diode D 1 and a second diode D 2 in series.
In this embodiment, as shown in fig. 1, K 1~K5 is an optocoupler switch, and on-off is controlled by a program; r 1~R12 is a voltage dividing resistor, wherein R 4、R5 is a sampling resistor, and the total voltage of the system is divided into small voltages and is input into an AD sampling chip for total voltage detection, wherein ADS is the AD sampling chip; d 1、D2 is a diode, which is used to limit the trend of the loop by using its unidirectional conductivity; front+ and Front-are the battery to high voltage tank connection (Front end), back+ and Back-are the load to high voltage tank connection (Back end), as shown in fig. 2.
Example 3
Based on embodiment 2, the present embodiment provides a method for detecting insulation resistance and total voltage of an energy storage BMS, including a total detection circuit connection step, a front-end total voltage detection step, a rear-end total voltage detection step, and an insulation resistance detection step;
The general detection circuit is grounded, the front end of the general detection circuit is connected to the connection part of the battery and the high-voltage box, and the rear end of the general detection circuit is connected to the connection part of the load end/grid-connected end and the high-voltage box; the total detection circuit comprises a sampling unit, a front-end positive electrode voltage division unit, a front-end negative electrode voltage division unit, a rear-end positive electrode voltage division unit, a rear-end negative electrode voltage division unit and a grounding unit;
Specifically, the front positive voltage dividing unit and the front negative voltage dividing unit of the total detection circuit are respectively connected with the positive electrode and the negative electrode at the joint of the battery and the high-voltage box, the rear positive voltage dividing unit and the rear negative voltage dividing unit of the total detection circuit are respectively connected with the positive electrode and the negative electrode at the joint of the load end/grid-connected end and the high-voltage box, and the grounding unit of the total detection circuit is grounded.
The front-end total voltage detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive voltage division unit, the sampling unit and the front-end negative voltage division unit to form a front-end total voltage detection circuit, collect voltages at two ends of the current passing through the sampling unit, and obtain front-end total voltage according to the collected voltages at the two ends;
The method comprises a back-end total voltage detection step, wherein a switch of a total detection circuit is controlled to enable current to sequentially pass through a back-end positive electrode voltage division unit, a sampling unit and a back-end negative electrode voltage division unit to form a back-end total voltage detection circuit, the sampling unit is used for collecting voltages at two ends of the current passing through, and then the back-end total voltage is obtained according to the collected voltages at the two ends;
and the insulation resistance detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive electrode voltage division unit, the sampling unit and the grounding unit respectively, form an insulation resistance detection circuit, collect the voltages of two ends through which the current passes by the sampling unit, and obtain the insulation resistance value of the positive electrode and the negative electrode of the battery system to the ground according to the collected voltages of the two ends and the front-end total voltage obtained in the front-end total voltage detection step.
Example 4
In the step of detecting the total front end voltage, the present embodiment is further improved on the basis of embodiment 3, when the total front end voltage is detected, the switches of the relays RY 1/RY3 and RY 2 in the high-voltage box are turned off, the first switch K 1 and the second switch K 2 of the total detection circuit are turned on, the third switch K 3, the fourth switch K 4 and the fifth switch K 5 of the total detection circuit are turned off, the total front end voltage detection circuit is connected, and the circuit enters the working mode of detecting the total front end voltage, and the equivalent circuit is shown in fig. 3. The front end total voltage is divided by R 1~R8, wherein R 1+R2+R3= R6+R7+R8=10MΩ,R4=R5 =20kΩ, the voltage at the two ends of R 4、R5 measured by the AD sampling chip is set as V 1, and the front end total voltage V Front is calculated through the number relation of the voltage dividing circuits, as follows:
。
Example 5
In the step of detecting the total voltage at the rear end, the embodiment is further improved on the basis of embodiment 3, when the total voltage at the rear end is detected, the switches of the relays RY 1/RY3 and RY 2 in the high-voltage box are closed, the third switch K 3 and the fifth switch K 5 of the total detection circuit are closed, the first switch K 1, the second switch K 2 and the fourth switch K 4 of the total detection circuit are turned off, the total voltage at the rear end is communicated, the D 1、D2 is positively conducted, and the circuit enters a working mode of detecting the total voltage at the rear end, and an equivalent circuit is shown in fig. 4. The back-end voltage is divided by R 3~R6,R9~R12, wherein R 3+R9+R10= R6+R11+R12=10MΩ,R4=R5 =20kΩ, let the voltage at the two ends of R4 and R5 measured by the AD sampling chip be V 2, calculate the back-end total voltage V Back by the number relation of the voltage dividing circuits, as follows:
。
example 6
In the insulation resistance detection, when the insulation resistance value is detected, K 3、K5 in fig. 1 is turned off, K 1、K2、K4 is orderly closed according to the setting, the circuit enters an insulation resistance detection working mode, the insulation resistance detection principle is as shown in fig. 5, a conventional bridge method is adopted, and R x and R y are respectively the insulation resistances of the positive electrode and the negative electrode of the battery system to the ground.
1. First, K 1、K2 is closed, and the front end total pressure V Front is first obtained:
2. Then turn off K 2, only turn on K 1、K4, divide the voltage by R 1~R4, the voltage at two ends of R 4 measured by the AD sampling chip is V 3, and the voltage at two ends of R x is V x obtained by the number relation of the divided circuits:
3. Then turn off K 1, only turn on K 2、K4, divide the voltage by R 5~R8, the voltage at two ends of R 5 measured by the AD sampling chip is V 4, and the voltage at two ends of R y is V y obtained by the number relation of the divided circuits:
4. Finally, from the relationship between R 1+R2+R3= R6+R7+R8=Ra and R 4=R5=Rb, insulation resistances R x and R y are derived:
。
While the embodiments of the present invention have been described in detail, the present invention is not limited to the embodiments described above, and various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the present invention, and these are intended to be included in the scope of the present invention as defined in the appended claims.
Claims (9)
1. A circuit for energy storage BMS insulation resistance and total voltage detection, its characterized in that: the device comprises a sampling unit, a front-end positive electrode voltage division unit, a front-end negative electrode voltage division unit, a rear-end positive electrode voltage division unit, a rear-end negative electrode voltage division unit and a grounding unit;
The sampling unit comprises an anode sampling resistor (R 4), a cathode sampling resistor (R 5) and a sampling module (1), wherein the anode sampling resistor (R 4) and the cathode sampling resistor (R 5) are connected in series, the sampling module (1) is respectively connected in parallel with two ends of the anode sampling resistor (R 4) and the cathode sampling resistor (R 5) to collect the voltages at two ends of the anode sampling resistor (R 4) and the cathode sampling resistor (R 5);
The front-end positive voltage dividing unit is connected with the positive sampling resistor (R 4) and comprises a plurality of front-end positive voltage dividing resistors connected in series and a first switch (K 1) for controlling the on-off of the front-end positive voltage dividing unit; the front-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor (R 5) and comprises a plurality of front-end negative electrode voltage dividing resistors connected in series and a second switch (K 2) for controlling the on-off of the front-end negative electrode voltage dividing unit; the front-end positive voltage dividing unit, the sampling unit and the front-end negative voltage dividing unit are sequentially connected in series to form a front-end total voltage detection circuit;
The rear-end positive voltage dividing unit is connected with the positive sampling resistor (R 4) and is connected with the front-end positive voltage dividing unit in parallel, and the rear-end positive voltage dividing unit comprises a plurality of rear-end positive voltage dividing resistors connected in series and a third switch (K 3) for controlling the on-off of the rear-end positive voltage dividing unit; the rear-end negative electrode voltage dividing unit is connected with the negative electrode sampling resistor (R 5) and is connected with the front-end negative electrode voltage dividing unit in parallel, and comprises a plurality of rear-end negative electrode voltage dividing resistors connected in series and a fifth switch (K 5) for controlling the on-off of the rear-end negative electrode voltage dividing unit; the rear end positive voltage dividing unit, the sampling unit and the rear end negative voltage dividing unit are sequentially connected in series to form a rear end total voltage detection circuit;
the grounding unit is connected to a line of which the positive sampling resistor (R 4) and the negative sampling resistor (R 5) are connected in series, and comprises a fourth switch (K 4) for controlling the on-off of the grounding unit; the front end positive electrode voltage division unit, the positive electrode sampling resistor (R 4) and the grounding unit are sequentially connected in series to form a positive electrode insulation resistance detection circuit, and the front end negative electrode voltage division unit, the negative electrode sampling resistor (R 5) and the grounding unit are sequentially connected in series to form a negative electrode insulation resistance detection circuit.
2. The insulation resistance and total voltage detection circuit according to claim 1, wherein: the positive sampling resistor is connected in series with a third resistor (R 3), and the negative sampling resistor is connected in series with a sixth resistor (R 6).
3. The insulation resistance and total voltage detection circuit according to claim 1, wherein: the front-end positive voltage dividing resistor comprises a first resistor (R 1) and a second resistor (R 2), and the first resistor (R 1), a first switch (K 1) and the second resistor (R 2) are sequentially connected in series; the front-end negative voltage dividing resistor comprises a seventh resistor (R 7) and an eighth resistor (R 8), and the seventh resistor (R 7), the second switch (K 2) and the eighth resistor (R 8) are sequentially connected in series.
4. The insulation resistance and total voltage detection circuit according to claim 1, wherein: the rear-end positive voltage dividing resistor comprises a ninth resistor (R 9) and a tenth resistor (R 10), and the ninth resistor (R 9), the third switch (K 3) and the tenth resistor (R 10) are sequentially connected in series; the rear-end negative voltage dividing resistor comprises an eleventh resistor (R 11) and a twelfth resistor (R 12), and the eleventh resistor (R 11), the fifth switch (K 5) and the twelfth resistor (R 12) are sequentially connected in series.
5. The insulation resistance and total voltage detection circuit according to claim 1, wherein: the rear-end positive electrode voltage division unit and the rear-end negative electrode voltage division unit are respectively connected with a first diode (D 1) and a second diode (D 2) in series.
6. The method for detecting the insulation resistance and the total voltage of the energy storage BMS is characterized by comprising the following steps of: the method comprises a total detection circuit connection step, a front-end total voltage detection step, a rear-end total voltage detection step and an insulation resistance detection step;
The general detection circuit is grounded, the front end of the general detection circuit is connected to the connection part of the battery and the high-voltage box, and the rear end of the general detection circuit is connected to the connection part of the load end/grid-connected end and the high-voltage box; wherein the total detection circuit is the circuit for detecting insulation resistance and total voltage according to any one of claims 1 to 5;
the front-end total voltage detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive voltage division unit, the sampling unit and the front-end negative voltage division unit to form a front-end total voltage detection circuit, collect voltages at two ends of the current passing through the sampling unit, and obtain front-end total voltage according to the collected voltages at the two ends;
The method comprises a back-end total voltage detection step, wherein a switch of a total detection circuit is controlled to enable current to sequentially pass through a back-end positive electrode voltage division unit, a sampling unit and a back-end negative electrode voltage division unit to form a back-end total voltage detection circuit, the sampling unit is used for collecting voltages at two ends of the current passing through, and then the back-end total voltage is obtained according to the collected voltages at the two ends;
and the insulation resistance detection step is to control the switch of the total detection circuit to enable current to sequentially pass through the front-end positive electrode voltage division unit, the sampling unit and the grounding unit respectively, form an insulation resistance detection circuit, collect the voltages of two ends through which the current passes by the sampling unit, and obtain the insulation resistance value of the positive electrode and the negative electrode of the battery system to the ground according to the collected voltages of the two ends and the front-end total voltage obtained in the front-end total voltage detection step.
7. The method for insulation resistance and total voltage detection as defined in claim 6, wherein: in the front end total voltage detection step, when the front end total voltage is detected, a first switch (K 1) and a second switch (K 2) of a total detection circuit are closed, a third switch (K 3), a fourth switch (K 4) and a fifth switch (K 5) of the total detection circuit are turned off, the front end total voltage detection circuit is communicated, a sampling module is used for collecting the total voltage V 1 at two ends of a positive electrode sampling resistor and a negative electrode sampling resistor, and the front end total voltage V Front is obtained:
，
Wherein, R 1 is a first resistor, R 2 is a second resistor, R 3 is a third resistor, R 4 is a positive sampling resistor, R 5 is a negative sampling resistor, R 6 is a sixth resistor, R 7 is a seventh resistor, and R 8 is an eighth resistor.
8. The method for insulation resistance and total voltage detection as defined in claim 6, wherein: in the step of detecting the total voltage of the rear end, when the total voltage of the rear end is detected, a third switch (K 3) and a fifth switch (K 5) of the total detection circuit are closed, a first switch (K 1), a second switch (K 2) and a fourth switch (K 4) of the total detection circuit are turned off, the total voltage detection circuit of the rear end is communicated, a sampling module is used for collecting the total voltage V 2 at two ends of a positive electrode sampling resistor and a negative electrode sampling resistor, and the total voltage V Back of the rear end is obtained:
，
Wherein R 3 is a third resistor, R 4 is a positive sampling resistor, R 5 is a negative sampling resistor, R 6 is a sixth resistor, R 9 is a ninth resistor, R 10 is a tenth resistor, R 11 is an eleventh resistor, and R 12 is a twelfth resistor.
9. The method for insulation resistance and total voltage detection as defined in claim 7, wherein: in the insulation resistance detection, when the insulation resistance value is detected, the method comprises the following steps:
a. Closing a first switch (K 1) and a fourth switch (K 4) of the total detection circuit, closing a second switch (K 2), a third switch (K 3) and a fifth switch (K 5) of the total detection circuit, communicating with the positive insulation resistance detection circuit, collecting voltage V 3 at two ends of a positive sampling resistor by using a sampling module, and obtaining voltage V x at two ends of a battery system positive insulation resistance R x:
，
in the middle of ,R1+R2+R3= R6+R7+R8=Ra,R4=R5=Rb;
B. Closing a second switch (K 2) and a fourth switch (K 4) of the total detection circuit, closing a first switch (K 1), a third switch (K 3) and a fifth switch (K 5) of the total detection circuit, communicating the negative insulation resistance detection circuit, collecting the voltage V 4 at two ends of a negative sampling resistor by using a sampling module, and obtaining the voltage V y at two ends of a battery system negative earth insulation resistor R y:
，
c. The front end total voltage V Front, the two-end voltage V 3 of the positive electrode sampling resistor, the two-end voltage V 4 of the negative electrode sampling resistor, the two-end voltage V x of the battery system positive electrode ground insulation resistor R x and the two-end voltage V y of the battery system negative electrode ground insulation resistor R y obtained in the front end total voltage detection step are utilized to obtain the resistance values of the battery system positive electrode ground insulation resistor R x and the battery system negative electrode ground insulation resistor R y:
。
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| CN103278776A (en) * | 2013-05-10 | 2013-09-04 | 浙江吉利汽车研究院有限公司杭州分公司 | Electric automobile battery insulation detecting system |
| CN109212421A (en) * | 2018-09-29 | 2019-01-15 | 欣旺达惠州电动汽车电池有限公司 | A kind of detection method of high voltage battery pack system total voltage and insulation resistance |
| CN113791278A (en) * | 2021-09-30 | 2021-12-14 | 蜂巢能源科技有限公司 | Battery pack insulation resistance detection method and device, battery pack and vehicle |
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| CN103278776A (en) * | 2013-05-10 | 2013-09-04 | 浙江吉利汽车研究院有限公司杭州分公司 | Electric automobile battery insulation detecting system |
| CN109212421A (en) * | 2018-09-29 | 2019-01-15 | 欣旺达惠州电动汽车电池有限公司 | A kind of detection method of high voltage battery pack system total voltage and insulation resistance |
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