A method for realizing load prediction by a BMS detection circuit

Abstract

The present application relates to battery management system and other technical fields, and provides a kind of BMS detection circuit implementation load pre-judgment method.To solve the technical problems that single current channel is used in existing BMS system, large-capacity load is easily misjudged as short circuit, and load type cannot be intelligently identified, the BMS detection circuit of the present application includes main loop channel, small / large load pre-judgment channel and differential voltage division network.The method comprises the following steps: when the load is connected, first turn on the small load pre-judgment channel, record multiple sets of differential voltage and loop current to calculate power and determine the load type;If the power exceeds the threshold, switch to the large load pre-judgment channel for further determination;If the conditions are met, turn on the main loop, otherwise, delay and retry or turn off all channels to protect.The present application can realize intelligent pre-judgment of load type, avoid the main loop MOS tube from being impacted by large current, and improve the safety and reliability of the system.

Description

Technical Field

[0001] This invention relates to the technical fields of battery management systems, and in particular to a method for load prediction using a BMS detection circuit. Background Technology

[0002] In a BMS system, accurate load detection and prediction are crucial to identify the load's size and type, thereby selecting appropriate power supply logic to improve lithium battery safety and lifespan. Different types of loads exhibit different current change slopes; for example, capacitive loads experience a high initial current followed by a decrease, while resistive loads maintain a constant current. By detecting the actual voltage across the load and the loop current, the load power can be calculated, providing a basis for power supply decisions.

[0003] Existing BMS systems typically use a single discharge MOSFET as the current path, such as Figure 2 As shown, the BMS detection and protection circuit controls the on / off state of the discharge MOSFET (DFET) via the DSG signal, and the sampling resistor Rsens is used to detect the loop current. Regardless of the load size, all current flows through the same MOSFET (DFET). In this scheme, when a load is connected, a current event typically occurs first, and then it is compared with a preset threshold to make a protection decision. When a large capacitive load is connected, the instantaneous current is large and easily misjudged as a short circuit, triggering a false protection operation. Even with the addition of a pre-charge circuit, because the voltage across the load is not sampled, the system still cannot distinguish between a true capacitive load and a true short circuit; if it is a true short circuit, it will still cause a short-circuit impact on the main loop MOSFET, affecting device reliability and system safety.

[0004] Therefore, existing solutions have technical problems such as the inability of a single current channel to adapt to different load requirements, the ease of misjudging short circuits, the inability to accurately determine the load type and power, and the lack of intelligent load identification capabilities. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for load prediction using a BMS detection circuit. The BMS detection circuit is electrically connected to a BMS detection and protection drive circuit powered by a battery (BAT) and a load (Load). The BMS detection circuit includes a main circuit channel, a small load prediction channel, and a large load prediction channel, as well as a differential voltage divider network connected across the load (Load) for acquiring differential voltage. The method includes: Step 1: When a load is connected, the small load prediction channel is in the on state, while the large load prediction channel and the main circuit channel are in the off state, and the current flows through the small load prediction channel. If the effective load voltage and current recording is not triggered, it is determined to be no load. If the effective load voltage and current recording is triggered, multiple sets of differential voltages and circuit currents of the on-line channel are recorded within a preset time period, multiple sets of load power are calculated, and the load type is determined based on the changing trend of the circuit current. Step 2: If the power of all the loads does not exceed the first channel power threshold, then shut down the small load prediction channel and turn on the main circuit channel; if there is a case where the power exceeds the first channel power threshold, then shut down the small load prediction channel and turn on the large load prediction channel, and proceed to Step 3. Step 3: Under the large load prediction channel, record multiple sets of differential voltages and circuit currents of the conduction channel within a preset time period, calculate the load power. If the re-recorded load power does not exceed the second channel power threshold, then turn off the large load prediction channel and turn on the main circuit channel; otherwise, proceed to step 4. Step 4: Clear the recorded data. After a preset delay, record multiple sets of voltage and current data again through the large load prediction channel and calculate the load power. If the load power obtained by the retry does not exceed the power threshold of the second channel, then turn on the main circuit channel; otherwise, turn off all channels and return to Step 1 after detecting that the load has been removed.

[0006] The beneficial effects of this invention are as follows: By setting up a main circuit channel, a small load prediction channel, and a large load prediction channel, this invention uses the small current channel to predict the load first when it is connected. It automatically selects to switch or directly open the main circuit according to the load power, avoiding the main circuit MOSFET from directly bearing the impact of large current, thus improving system reliability and device lifespan. At the same time, based on the trend of circuit current change, it can accurately identify resistive, capacitive, and inductive loads, preventing capacitive loads from being misjudged as short circuits, thus realizing intelligent load identification.

[0007] Furthermore, the conditions for triggering the recording of effective load voltage and current in step one are: the differential voltage is not equal to the battery voltage, or the loop current is greater than zero; the conditions for not triggering the recording of effective load voltage and current are: the differential voltage is equal to the battery voltage and the loop current is zero.

[0008] The beneficial effects of this invention are as follows: by using the relationship between differential voltage and battery voltage and the loop current value as the triggering conditions for effective load recording, it is possible to accurately distinguish between no-load and loaded states, providing a reliable starting point for subsequent power calculation and type judgment.

[0009] Furthermore, in step one, determining the load type based on the changing trend of the loop current includes: if the multiple sets of loop current values ​​are equal, it is determined to be a resistive load; if they decrease sequentially, it is determined to be a capacitive load; if they increase sequentially, it is determined to be an inductive load.

[0010] The beneficial effects of this invention are as follows: the load type is determined by the equal, decreasing or increasing trend of multiple sets of loop current values. The algorithm is simple, does not require complex MCU calculations, can reduce the real-time requirements of the controller, and save system resources.

[0011] Furthermore, the differential voltage divider network includes a first voltage divider resistor network and a second voltage divider resistor network connected to both ends of the load; the recording of the differential voltage in step one includes: acquiring a first voltage using the first voltage divider resistor network, acquiring a second voltage using the second voltage divider resistor network, and using the difference between the first voltage and the second voltage as the differential voltage to eliminate line voltage drop.

[0012] The beneficial effects of this invention are as follows: by using a differential voltage divider network to collect the differential voltage across the load, the line voltage drop can be effectively eliminated, the true load voltage can be obtained, and the load power can be accurately calculated, providing an accurate basis for channel switching and power supply decisions.

[0013] Furthermore, the first channel power threshold is the battery voltage multiplied by the limiting current of the predicted channel under small load, and the second channel power threshold is the battery voltage multiplied by the limiting current of the predicted channel under large load.

[0014] The beneficial effects of this invention are as follows: the power threshold is obtained by multiplying the battery voltage by the channel limiting current, which is directly matched with the current limiting capability of each prediction channel. This ensures that the current does not exceed the limit during the prediction stage, and also allows for a reasonable determination of whether the main circuit can be opened.

[0015] Furthermore, the preset delay time in step four is 10 seconds.

[0016] The beneficial effects of this invention are as follows: setting a 10-second delay retry mechanism in step four can effectively filter out instantaneous high-power interference or brief surges during load startup, avoid accidental shutdown, and improve load adaptability.

[0017] Furthermore, the method for detecting load removal in step four is: determining that the load has been removed by the differential voltage being zero.

[0018] The beneficial effects of this invention are as follows: by detecting that the differential voltage is zero, the load is removed, and automatic reset is achieved, so that the system can respond promptly to the next load connection.

[0019] Furthermore, the first voltage divider resistor network includes: voltage divider resistor RV1 and voltage divider resistor RV2. One end of voltage divider resistor RV1 is connected to the positive terminal P+ of the load Load and the positive terminal of the battery BAT. The other end of voltage divider resistor RV1 is connected to one end of voltage divider resistor RV2 and the voltage acquisition terminal ADC1 of the BMS detection and protection drive circuit. The other end of voltage divider resistor RV2 is grounded. The second voltage divider resistor network includes: voltage divider resistor RV3 and voltage divider resistor RV4. One end of voltage divider resistor RV4 is connected to the negative terminal P- of the load Load, and the other end is connected to one end of voltage divider resistor RV3 and the voltage acquisition terminal ADC2 of the BMS detection and protection drive circuit. The other end of voltage divider resistor RV3 is grounded.

[0020] The beneficial effects of this invention are as follows: the first and second voltage divider resistor networks have simple and reliable structures. By acquiring and subtracting the voltage from the ADC, the true load voltage can be obtained. At the same time, when the voltage is zero, it indicates that the load has been removed, achieving two goals at once.

[0021] Furthermore, the main circuit channel includes a MOSFET DFET3 and a current acquisition resistor Rsens; the source of the MOSFET DFET3 is connected to the negative terminal P- of the load Load, the gate is connected to the drive signal output terminal DSG3 of the BMS detection and protection drive circuit, and the drain is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

[0022] The beneficial effects of this invention are as follows: the main circuit channel uses a MOSFET DFET3 and a current acquisition resistor Rsens, which are powered by a low impedance channel during normal operation, resulting in low power consumption and continuous monitoring of the circuit current.

[0023] Furthermore, the small load prediction channel includes a resistor RP1, a MOSFET DFET1, and a current acquisition resistor Rsens. One end of the resistor RP1 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of the MOSFET DFET1. The gate of the MOSFET DFET1 is connected to the drive signal output terminal DSG1 of the BMS detection and protection drive circuit. The drain of the MOSFET DFET1 is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit. The large load prediction channel includes a resistor RP2, a MOSFET DFET2, and a current acquisition resistor Rsens. One end of the resistor RP2 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of the MOSFET DFET2. The gate of the MOSFET DFET2 is connected to the drive signal output terminal DSG2 of the BMS detection and protection drive circuit. The drain of the MOSFET DFET2 is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

[0024] The beneficial effects of this invention are as follows: the small load prediction channel and the large load prediction channel are respectively connected in series with resistors RP1 and RP2 for current limiting, and the on and off are controlled by independent MOS transistors. The structure is simple, realizes hierarchical prediction, and protects the safety of devices and batteries. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. Some specific embodiments of the invention will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings designate the same or similar parts or components. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a flowchart of the method for load prediction implemented by the BMS detection circuit in an embodiment of the present invention; Figure 2 This is a circuit schematic diagram of a traditional BMS detection circuit; Figure 3 This is a circuit schematic diagram of a BMS detection circuit according to an embodiment of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] Example 1 See Figure 3 This embodiment provides a BMS detection circuit, which is electrically connected to the BMS detection and protection drive circuit and the load Load. The battery BAT is also electrically connected to the BMS detection and protection drive circuit and the load Load to supply power. The positive terminal B+ of the battery BAT is connected to the positive terminal P+ of the load Load, and the negative terminal B- is grounded through the current acquisition resistor Rsens. The BMS detection and protection drive circuit has at least three drive signal output terminals DSG1, DSG2, and DSG3, two voltage acquisition terminals ADC1 and ADC2, and one current signal acquisition terminal connected to the current acquisition resistor Rsens to acquire the current signal.

[0028] The BMS detection circuit includes a main circuit channel, a small load prediction channel, and a large load prediction channel, as well as a differential voltage divider network connected to both ends of the load (Load) for acquiring differential voltage.

[0029] The main circuit channel includes a MOSFET DFET3 and a current acquisition resistor Rsens; the source of the MOSFET DFET3 is connected to the negative terminal P- of the load Load, the gate is connected to the drive signal output terminal DSG3 of the BMS detection and protection drive circuit, and the drain is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

[0030] The small load prediction channel includes a resistor RP1, a MOSFET DFET1, and a current acquisition resistor Rsens. One end of the resistor RP1 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of the MOSFET DFET1. The gate of the MOSFET DFET1 is connected to the drive signal output terminal DSG1 of the BMS detection and protection drive circuit, and the drain is grounded through the current acquisition resistor Rsens. The current acquisition resistor Rsens is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

[0031] The large load prediction channel includes a resistor RP2, a MOSFET DFET2, and a current acquisition resistor Rsens. One end of the resistor RP2 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of the MOSFET DFET2. The gate of the MOSFET DFET2 is connected to the drive signal output terminal DSG2 of the BMS detection and protection drive circuit, and the drain is grounded through the current acquisition resistor Rsens. The current acquisition resistor Rsens is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

[0032] The differential voltage divider network includes a first voltage divider resistor network and a second voltage divider resistor network connected across the load Load. The first voltage divider resistor network includes voltage divider resistors RV1 and RV2. One end of RV1 is connected to the positive terminal P+ of the load Load and the positive terminal of the battery BAT. The other end of RV1 is connected to one end of RV2 and to the voltage acquisition terminal ADC1 of the BMS detection and protection drive circuit. The other end of RV2 is grounded. The second voltage divider resistor network includes voltage divider resistors RV3 and RV4. One end of RV4 is connected to the negative terminal P- of the load Load. The other end of RV4 is connected to one end of RV3 and to the voltage acquisition terminal ADC2 of the BMS detection and protection drive circuit. The other end of RV3 is grounded. The differential voltage across the load Load is obtained by the difference between the voltage acquired by voltage acquisition terminal ADC1 and the voltage acquired by voltage acquisition terminal ADC2, eliminating line voltage drop and reflecting the true voltage of the load Load.

[0033] In this embodiment, the current limit for the small load prediction channel is set to 1A, the current limit for the large load prediction channel is set to 10A, and the main circuit channel is a low impedance channel that can carry the rated operating current.

[0034] Example 2 See Figure 1 and Figure 3 This embodiment provides a method for load prediction using a BMS detection circuit, which employs the BMS detection circuit described in Embodiment 1. The BMS detection circuit is electrically connected to a BMS detection and protection drive circuit powered by a battery (BAT) and a load (Load). The BMS detection circuit includes a main circuit channel, a small load prediction channel, and a large load prediction channel, as well as a differential voltage divider network connected across the load (Load) for acquiring differential voltage. The method includes the following steps.

[0035] Step 1: When a load is connected, the small load prediction channel is in the conducting state, while the large load prediction channel and the main circuit channel are in the disconnected state, and the current flows through the small load prediction channel. If the effective load voltage and current recording is not triggered, it is determined to be no load. If the effective load voltage and current recording is triggered, multiple sets of differential voltages and circuit currents of the conducting channel are recorded within a preset time period, multiple sets of load power are calculated, and the load type is determined based on the changing trend of the circuit current.

[0036] In the initial state, the BMS detection and protection drive circuit outputs a valid drive signal through the drive signal output terminal DSG1, turning on MOSFET DFET1 and enabling the small load prediction channel. It outputs invalid drive signals through the drive signal output terminals DSG2 and DSG3, turning off MOSFETs DFET2 and DFET3, thus disconnecting the large load prediction channel and the main circuit channel. When the load Load is connected between P+ and P-, the current path is: battery BAT positive terminal B+ → load Load positive terminal P+ → load Load → load Load negative terminal P- → resistor RP1 → MOSFET DFET1 → current acquisition resistor Rsens → battery BAT negative terminal B-.

[0037] The BMS detection and protection drive circuit acquires differential voltage in real time through a differential voltage divider network. The differential voltage divider network includes a first voltage divider resistor network and a second voltage divider resistor network connected across the load (Load). Recording the differential voltage involves: acquiring a first voltage using the first voltage divider resistor network, acquiring a second voltage using the second voltage divider resistor network, and using the difference between the first and second voltages as the differential voltage to eliminate line voltage drop. Specifically, the first voltage divider resistor network includes voltage divider resistors RV1 and RV2, and the second voltage divider resistor network includes voltage divider resistors RV3 and RV4. The voltage at one end of voltage divider resistor RV2 acquired by the voltage acquisition terminal ADC1 is used as the first voltage, and the voltage at one end of voltage divider resistor RV3 acquired by the voltage acquisition terminal ADC2 is used as the second voltage. The difference between the first and second voltages is the differential voltage U across the load (Load).

[0038] In step 1, the condition for triggering the active load voltage and current recording is: the differential voltage is not equal to the battery voltage, or the loop current is greater than zero; the condition for not triggering the active load voltage and current recording is: the differential voltage is equal to the battery voltage and the loop current is zero. If the BMS detection and protection drive circuit detects that the differential voltage U is equal to the voltage VBAT of the battery BAT and the loop current I is equal to zero, it is determined that the active load voltage and current recording is not triggered, at this time, it is determined as no-load, and the circuit maintains the current state to continue monitoring.

[0039] If the BMS detection and protection drive circuit detects that the differential voltage U is not equal to the voltage VBAT of the battery BAT, or the loop current I is greater than zero, the active load voltage and current recording is triggered. Multiple sets of the differential voltage and the loop current of the conduction channel are recorded within a preset time period. In this embodiment, the preset time period is 1 second, and 3 sets of differential voltage and loop current data of the conduction channel are recorded, which are respectively: (U1, I1), (U2, I2), (U3, I3). Multiple sets of load power are calculated, which are respectively: P1=U1×I1, P2=U2×I2, P3=U3×I3.

[0040] Judging the load type according to the change trend of the loop current includes: if the multiple sets of loop current values are equal, that is, I1=I2=I3, it is judged as a resistive load; if they decrease sequentially, that is, I1>I2>I3, it is judged as a capacitive load; if they increase sequentially, that is, I1<I2<I3, it is judged as an inductive load.

[0041] Step 2: If none of the multiple sets of load power exceeds the first channel power threshold, turn off the small load pre-judgment channel and turn on the main loop channel; if there is a case where the first channel power threshold is exceeded, turn off the small load pre-judgment channel and turn on the large load pre-judgment channel, then perform step 3.

[0042] Wherein, the first channel power threshold is the battery voltage multiplied by the limit current of the small load pre-judgment channel. In this embodiment, the limit current of the small load pre-judgment channel is 1A, so the first channel power threshold PCH1-MAX=VBAT×1A.

[0043] If the three load powers P1, P2, and P3 calculated in step one all do not exceed the first channel power threshold PCH1-MAX, i.e., P1≤PCH1-MAX, P2≤PCH1-MAX, and P3≤PCH1-MAX, then the load power is within the tolerance range of the battery and the small load prediction channel. The BMS detection and protection drive circuit outputs an invalid drive signal through the drive signal output terminal DSG1, turning off the MOSFET DFET1, thereby turning off the small load prediction channel; at the same time, it outputs an valid drive signal through the drive signal output terminal DSG3, turning on the MOSFET DFET3, thereby turning on the main circuit channel, and the battery BAT normally supplies power to the load Load through the main circuit channel. At this time, the current path is: battery BAT positive terminal B+ → load Load positive terminal P+ → load Load → load Load negative terminal P- → MOSFET DFET3 → current acquisition resistor Rsens → battery BAT negative terminal B-.

[0044] If the power threshold of the first channel is exceeded, i.e., any one of P1, P2, and P3 is greater than PCH1-MAX, the BMS detection and protection drive circuit outputs an invalid drive signal through the drive signal output terminal DSG1 to turn off the MOSFET DFET1, thereby turning off the small load prediction channel; at the same time, it outputs an valid drive signal through the drive signal output terminal DSG2 to turn on the MOSFET DFET2, thereby turning on the large load prediction channel and executing step three.

[0045] Step 3: Under the large load prediction channel, record multiple sets of differential voltages and circuit currents of the conduction channel within a preset time period, calculate the load power. If the re-recorded load power does not exceed the second channel power threshold, then turn off the large load prediction channel and turn on the main circuit channel; otherwise, proceed to step 4.

[0046] The second channel power threshold is calculated by multiplying the battery voltage by the limiting current of the high load prediction channel. In this embodiment, the limiting current of the high load prediction channel is 10A, therefore the second channel power threshold PCH2-MAX = VBAT × 10A.

[0047] After the high load prediction channel is turned on, the current path is: battery BAT positive terminal B+ → load Load positive terminal P+ → load Load → load Load negative terminal P- → resistor RP2 → MOSFET DFET2 → current acquisition resistor Rsens → battery BAT negative terminal B-. Multiple sets of differential voltages and loop currents of the turned-on channel are re-recorded within a preset time period. In this embodiment, the preset time period is 1 second, and three sets of data are re-recorded: (U4, I4), (U5, I5), and (U6, I6). The load power is calculated as follows: P4 = U4 × I4, P5 = U5 × I5, P6 = U6 × I6.

[0048] If the re-recorded load powers P4, P5, and P6 all do not exceed the second channel power threshold PCH2-MAX (i.e., P4≤PCH2-MAX, P5≤PCH2-MAX, and P6≤PCH2-MAX), it indicates that the load power is within the tolerance range of the large load prediction channel. The BMS detection and protection drive circuit outputs an invalid drive signal through the drive signal output terminal DSG2 to turn off the MOSFET DFET2, thereby turning off the large load prediction channel; simultaneously, it outputs an valid drive signal through the drive signal output terminal DSG3 to turn on the MOSFET DFET3, thereby turning on the main circuit channel, allowing the battery BAT to normally supply power to the load Load through the main circuit channel.

[0049] If any of the three re-recorded load power groups exceeds the second channel power threshold, i.e., any one of P4, P5, or P6 is greater than PCH2-MAX, then proceed to step four.

[0050] Step 4: Clear the recorded data. After a preset delay, record multiple sets of voltage and current data again through the large load prediction channel and calculate the load power. If the load power obtained by the retry does not exceed the power threshold of the second channel, then turn on the main circuit channel; otherwise, turn off all channels and return to Step 1 after detecting that the load has been removed.

[0051] The preset delay time is 10 seconds. After clearing all previously recorded data, a 10-second delay is set, and multiple sets of voltage and current data are recorded again through the large load prediction channel, and the load power is calculated. That is, the large load prediction channel remains on, and after a 10-second delay, three sets of voltage and current data are recorded again, and the load power is calculated.

[0052] If the power of the three load groups obtained from the retry does not exceed the second channel power threshold PCH2-MAX, the BMS detection and protection drive circuit outputs an invalid drive signal through the drive signal output terminal DSG2, turns off the MOSFET DFET2, and thus turns off the large load prediction channel; at the same time, it outputs an valid drive signal through the drive signal output terminal DSG3, turns on the MOSFET DFET3, and thus turns on the main circuit channel, so that the battery BAT can supply power to the load Load normally through the main circuit channel.

[0053] If any of the three sets of load power obtained from the retry still exceeds the second channel power threshold PCH2-MAX, then the load power is determined to be beyond the capacity of the battery BAT. The BMS detection and protection drive circuit outputs invalid drive signals through the drive signal output terminals DSG1, DSG2, and DSG3, causing MOSFETs DFET1, DFET2, and DFET3 to be turned off, thereby shutting down all channels and stopping power supply to the load.

[0054] Then, the BMS detection and protection drive circuit continuously monitors the differential voltage. It detects load removal by determining that the load has been removed when the differential voltage is zero. When the BMS detection and protection drive circuit detects that the differential voltage obtained through voltage acquisition terminals ADC1 and ADC2 is zero, it determines that the load has been removed. At this point, it returns to step one: the BMS detection and protection drive circuit outputs a valid drive signal through the drive signal output terminal DSG1, turning on MOSFET DFET1 and putting the small load prediction channel on; it outputs invalid drive signals through the drive signal output terminals DSG2 and DSG3, turning off MOSFET DFET2 and DFET3, and putting the large load prediction channel and the main circuit channel off, waiting for the next load to be connected.

[0055] Through the above steps, this invention can predict the load connection with a small current channel in advance, and automatically select to switch or directly open the main circuit according to the load power, so as to avoid the MOSFET DFET3 in the main circuit channel being directly subjected to a large current impact, thereby improving system reliability and device life; at the same time, it can accurately judge resistive load, capacitive load and inductive load based on the changing trend of the circuit current, prevent capacitive load from being misjudged as a short circuit, and realize intelligent load identification.

[0056] It should be noted that the above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention, and the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for load prediction using a BMS detection circuit, characterized in that... The BMS detection circuit is electrically connected to the BMS detection and protection drive circuit powered by the battery (BAT) and the load (Load). The BMS detection circuit includes a main circuit channel, a small load prediction channel, and a large load prediction channel, as well as a differential voltage divider network connected across the load (Load) for acquiring differential voltage. The method includes: Step 1: When a load is connected, the small load prediction channel is in the on state, while the large load prediction channel and the main circuit channel are in the off state, and the current flows through the small load prediction channel. If the effective load voltage and current recording is not triggered, it is determined to be no load. If the effective load voltage and current recording is triggered, multiple sets of differential voltages and circuit currents of the on-line channel are recorded within a preset time period, multiple sets of load power are calculated, and the load type is determined based on the changing trend of the circuit current. Step 2: If the power of all the loads does not exceed the first channel power threshold, then shut down the small load prediction channel and turn on the main circuit channel; if there is a case where the power exceeds the first channel power threshold, then shut down the small load prediction channel and turn on the large load prediction channel, and proceed to Step 3. Step 3: Under the large load prediction channel, record multiple sets of differential voltages and circuit currents of the conduction channel within a preset time period, calculate the load power. If the re-recorded load power does not exceed the second channel power threshold, then turn off the large load prediction channel and turn on the main circuit channel; otherwise, proceed to step 4. Step 4: Clear the recorded data. After a preset delay, record multiple sets of voltage and current data again through the large load prediction channel and calculate the load power. If the load power obtained by the retry does not exceed the power threshold of the second channel, then turn on the main circuit channel; otherwise, turn off all channels and return to Step 1 after detecting that the load has been removed.

2. The method according to claim 1, characterized in that, The conditions for triggering the recording of effective load voltage and current in step one are: the differential voltage is not equal to the battery voltage, or the loop current is greater than zero; the conditions for not triggering the recording of effective load voltage and current are: the differential voltage is equal to the battery voltage and the loop current is zero.

3. The method according to claim 1, characterized in that, In step one, determining the load type based on the changing trend of the loop current includes: if the multiple sets of loop current values ​​are equal, it is determined to be a resistive load; if they decrease sequentially, it is determined to be a capacitive load; if they increase sequentially, it is determined to be an inductive load.

4. The method according to claim 1, characterized in that, The differential voltage divider network includes a first voltage divider resistor network and a second voltage divider resistor network connected to both ends of the load; the step of recording the differential voltage includes: using the first voltage divider resistor network to collect a first voltage, using the second voltage divider resistor network to collect a second voltage, and using the difference between the first voltage and the second voltage as the differential voltage to eliminate line voltage drop.

5. The method according to claim 1, characterized in that, The first channel power threshold is the battery voltage multiplied by the limiting current of the predicted channel under small load, and the second channel power threshold is the battery voltage multiplied by the limiting current of the predicted channel under large load.

6. The method according to claim 1, characterized in that, The preset delay time in step four is 10 seconds.

7. The method according to claim 1, characterized in that, The method for detecting load removal in step four is as follows: the load is determined to have been removed by the differential voltage being zero.

8. The method according to claim 4, characterized in that, The first voltage divider resistor network includes: voltage divider resistor RV1 and voltage divider resistor RV2. One end of voltage divider resistor RV1 is connected to the positive terminal P+ of the load Load and the positive terminal of the battery BAT. The other end of voltage divider resistor RV1 is connected to one end of voltage divider resistor RV2 and the voltage acquisition terminal ADC1 of the BMS detection and protection drive circuit. The other end of voltage divider resistor RV2 is grounded. The second voltage divider resistor network includes: voltage divider resistor RV3 and voltage divider resistor RV4. One end of voltage divider resistor RV4 is connected to the negative terminal P- of the load Load, and the other end is connected to one end of voltage divider resistor RV3 and the voltage acquisition terminal ADC2 of the BMS detection and protection drive circuit. The other end of voltage divider resistor RV3 is grounded.

9. The method according to any one of claims 1-8, characterized in that, The main circuit channel includes a MOSFET DFET3 and a current acquisition resistor Rsens; the source of the MOSFET DFET3 is connected to the negative terminal P- of the load Load, the gate is connected to the drive signal output terminal DSG3 of the BMS detection and protection drive circuit, and the drain is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

10. The method according to any one of claims 1-8, characterized in that, The small load prediction channel includes a resistor RP1, a MOSFET DFET1, and a current acquisition resistor Rsens. One end of resistor RP1 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of MOSFET DFET1. The gate of MOSFET DFET1 is connected to the drive signal output terminal DSG1 of the BMS detection and protection drive circuit. The drain of MOSFET DFET1 is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit. The large load prediction channel includes a resistor RP2, a MOSFET DFET2, and a current acquisition resistor Rsens. One end of resistor RP2 is connected to the negative terminal P- of the load Load, and the other end is connected to the source of MOSFET DFET2. The gate of MOSFET DFET2 is connected to the drive signal output terminal DSG2 of the BMS detection and protection drive circuit. The drain of MOSFET DFET2 is grounded through the current acquisition resistor Rsens, which is connected to the current signal acquisition terminal of the BMS detection and protection drive circuit.

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