An intelligent BDU voltage detection circuit

Abstract

The present invention provides an intelligent BDU voltage detection circuit, including a power module, a controller, a voltage sampling module, a multi-channel voltage-dividing circuit, and a channel switching module; the controller is connected to the voltage sampling module in communication; multiple input ends of the multi-channel voltage-dividing circuit are respectively connected to multiple load-end voltages of a power battery, and in the multi-channel voltage-dividing circuit, multiple output ends of some voltage-dividing circuits are respectively connected to multiple input ends of the channel switching module in a one-to-one correspondence; the output end of the channel switching module is connected to a voltage sampling end of the voltage sampling module, and the channel switching module is used to select one path from multiple output signals of the partial voltage-dividing circuit for differential output. The signal acquisition method of the present invention, which selects one path for output from multiple load-end voltages, can avoid directly inputting all load-end voltages into the voltage sampling module for acquisition, saves the hardware resources of the voltage sampling module, reduces the load of the voltage sampling module, and greatly reduces the cost.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage power distribution, and in particular to an intelligent BDU voltage detection circuit. Background Art

[0002] At present, electric vehicles are becoming more and more popular. Power batteries are one of the important components of electric vehicles. Lithium-ion batteries are usually used as power batteries for electric vehicles. Lithium-ion batteries have the advantages of high energy density, no memory effect, high cycle life and low self-discharge rate. Power batteries have very high requirements for internal voltages, such as the total voltage of the power battery, the load terminal voltage, etc. Improper use will seriously damage the battery, affect the service life of the power battery, and even cause the battery to burn and explode, causing serious loss of life and property. Therefore, real-time detection of the internal voltages of the power battery is crucial to ensure the safety of the power battery.

[0003] The high-voltage distribution box (BDU) of electric vehicles serves as the power distribution unit of the system and has the function of detecting the voltages of various channels inside the power battery. The common practice is to directly transmit all the collected single-ended voltage signals to the voltage sampling module. In this way, when there are many channels for collection, the pin resources of a single voltage sampling module are limited and may not meet the requirements. The cost is high, and the single-ended collection method will generate more EMI and has low anti-interference ability. Summary of the invention

[0004] The problem solved by the present invention is that the voltage detection method of the traditional BDU voltage detection circuit, in which single-end acquisition and all signals are directly input into the voltage sampling module, has high cost and low anti-interference ability.

[0005] In order to solve the above problems, the present invention proposes an intelligent BDU voltage detection circuit, including a power module, a controller, a voltage sampling module, a multi-channel voltage dividing circuit, and a channel switching module; the controller is communicatively connected to the voltage sampling module; multiple input ends of the multi-channel voltage dividing circuit are respectively connected to multiple load end voltages of the power battery, and in the multi-channel voltage dividing circuit, multiple output ends of some voltage dividing circuits are respectively connected to multiple input ends of the channel switching module in a one-to-one correspondence; the output end of the channel switching module is connected to a voltage sampling end of the voltage sampling module, and the channel switching module is used to select one path from multiple output signals of the partial voltage dividing circuit for differential output.

[0006] Optionally, the intelligent BDU voltage detection circuit also includes a differential amplifier module, which is connected between the output end of the channel switching module and the voltage sampling end of the voltage sampling module. The differential signal output by the channel switching module is respectively input into the two input ends of the differential amplifier module, and the output end of the differential amplifier module is connected to the voltage sampling end of the voltage sampling module.

[0007] Optionally, the intelligent BDU voltage detection circuit also includes a voltage follower module, which is connected between the output end of the channel switching module and the two input ends of the differential amplifier module. The differential signal output by the channel switching module is respectively input into the two in-phase input ends of the voltage follower module, and the two output ends of the voltage follower module are respectively connected to the two input ends of the differential amplifier module in a one-to-one correspondence.

[0008] Optionally, the channel switching module includes a HEF4052B-Q100 chip; in the multi-channel voltage divider circuit, the output end of the first voltage divider circuit is connected to the 1Y2 pin of the HEF4052B-Q100 chip, the output end of the second voltage divider circuit is connected to the 1Y0 pin and 1Y1 pin of the HEF4052B-Q100 chip at the same time, the output end of the third voltage divider circuit is connected to the 2Y1 pin of the HEF4052B-Q100 chip, and the output end of the fourth voltage divider circuit is connected to the 2Y2 pin of the HEF4052B-Q100 chip; the 1Z and 2Z pins of the HEF4052B-Q100 chip are respectively connected to the two in-phase input ends of the voltage follower module in a one-to-one correspondence.

[0009] Optionally, the output end of the power supply module is respectively connected to the power supply ends of the controller and the voltage sampling module, and the power supply end of the voltage sampling module is respectively connected to the power supply ends of the channel switching module, the voltage follower module and the differential amplifier module.

[0010] Optionally, the intelligent BDU voltage detection circuit also includes an isolation transformer, which is connected between the output end of the power supply module and the power supply end of the voltage sampling module, and is used to convert the output voltage of the power supply module into the supply voltage of the voltage sampling module.

[0011] Optionally, the intelligent BDU voltage detection circuit also includes a voltage reversal module, the input end of the voltage reversal module is connected to the power supply end of the voltage sampling module, and the power supply end of the voltage sampling module is also respectively connected to the positive pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, and the output end of the voltage reversal module is respectively connected to the negative pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, and the voltage reversal module is used to convert the positive voltage output by the power supply end of the voltage sampling module into a negative voltage.

[0012] Optionally, in the multi-channel voltage-dividing circuit of the intelligent BDU voltage detection circuit, multiple output ends of another part of the voltage-dividing circuit are directly connected to multiple voltage sampling ends of the voltage sampling module in a one-to-one correspondence.

[0013] Compared with the prior art, the intelligent BDU voltage detection circuit of the present invention has the following advantages:

[0014] (1) The intelligent BDU voltage detection circuit described in the present invention can effectively monitor multiple load-end voltages of the power battery, thereby improving the safety of the power battery. The signal acquisition method of selecting one output from multiple load-end voltages can avoid directly inputting all load-end voltages into the voltage sampling module for acquisition, thereby saving the hardware resources of the voltage sampling module, reducing the load of the voltage sampling module, and greatly reducing the cost. The method of differentially acquiring the load-end voltage of the power battery through the channel switching module can improve the anti-interference ability of the circuit and effectively suppress EMI, thereby improving the signal acquisition accuracy.

[0015] (2) The differential amplifier module in the intelligent BDU voltage detection circuit of the present invention can effectively suppress the common-mode input signal, amplify the differential-mode input signal, and can input the influence of environmental factors such as temperature on the circuit as a common-mode signal, which can effectively suppress the occurrence of zero-point drift;

[0016] (3) The voltage follower module in the intelligent BDU voltage detection circuit of the present invention performs impedance matching on the positive and negative input terminals of the differential amplifier module, thereby offsetting the voltage drop caused by the offset current of the positive and negative input terminals and improving the output accuracy of the differential amplifier module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural block diagram of the intelligent BDU voltage detection circuit according to an embodiment of the present invention;

[0018] Figure 2 A circuit diagram of a voltage sampling module according to an embodiment of the present invention;

[0019] Figure 3 A circuit diagram of a voltage divider circuit according to an embodiment of the present invention;

[0020] Figure 4 A circuit diagram of a differential amplifier module according to an embodiment of the present invention;

[0021] Figure 5 A circuit diagram of a voltage follower module according to an embodiment of the present invention;

[0022] Figure 6 A circuit diagram of a channel switching module according to an embodiment of the present invention;

[0023] Figure 7 The circuit diagram of the voltage inversion module according to the embodiment of the present invention is shown in FIG. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, it is an intelligent BDU voltage detection circuit in this embodiment, including a power module, a controller, a voltage sampling module, a multi-channel voltage dividing circuit, and a channel switching module; the controller is communicatively connected to the voltage sampling module; the multiple input ends of the multi-channel voltage dividing circuit are respectively connected to the multiple load end voltages of the power battery, and in the multi-channel voltage dividing circuit, the multiple output ends of some voltage dividing circuits are respectively connected to the multiple input ends of the channel switching module in a one-to-one correspondence; the output end of the channel switching module is connected to a voltage sampling end of the voltage sampling module, and the channel switching module is used to select one way from the multiple output signals of the partial voltage dividing circuit for differential output.

[0026] Among them, the partial voltage divider circuit can be some of the multi-way voltage divider circuits, or all of them. The load terminal voltage includes the electromagnetic terminal voltage, the pre-charging resistance voltage, the output positive circuit terminal voltage, the fast charging positive terminal voltage, the heating circuit voltage, the output negative circuit terminal voltage, the fast charging negative terminal voltage, etc. This embodiment is described as a voltage divider circuit with 7 circuits. The power module is used to power each module and circuit. The controller is connected to the voltage sampling module SPI communication.

[0027] Specifically, the preferred controller in this embodiment is the MPC5741PK1AMLQ5 chip; the power module includes the MC33FS4500CAE chip, and the MC33FS4500CAE chip outputs one 3.3V and three 5V voltages; Figure 2 As shown, the voltage sampling module includes the MM9Z1_638D1 chip, and the SPI communication port of the MM9Z1_638D1 chip includes the PA0 pin, the PA1 pin, the PA2 pin, and the PA3 pin, which are respectively connected to the CS pin, the SLK pin, the MISO pin, and the MOSI pin of the MPC5741PK1AMLQ5 chip. Figure 3 As shown, the voltage divider circuit adopts the form of resistor voltage divider, which is used to divide the voltages of multiple load terminals of the power battery. One voltage divider circuit in the figure includes resistor R309, resistor R310-resistor R318, resistor R318, resistor R317, ..., resistor R310, resistor R309 are connected in series to the ground in sequence, the common end of resistor R310 and resistor R309 is connected to the input end of the channel switching module, the common end of resistor R310 and resistor R309 is the output end of the voltage divider circuit, and the end of resistor R318 relative to resistor R317 is the input end of the voltage divider circuit.

[0028] In this embodiment, multiple load-end voltages of the power battery are divided by a voltage divider circuit and then input into a channel switching module. The channel switching module has multiple input terminals and two output terminals. The two output terminals respectively output two differential signals. Multiple load-end voltages of the power battery are respectively input into the multiple input terminals of the channel switching module. The channel switching module selects one from the multiple input load-end voltages for differential output. The MM9Z1_638D1 chip differentially collects the differential signals output by the channel switching module.

[0029] In this way, the intelligent BDU voltage detection circuit in this embodiment can effectively monitor multiple load-end voltages of the power battery, thereby improving the safety of the power battery. The signal acquisition method of selecting one output from multiple load-end voltages can avoid directly inputting all load-end voltages into the voltage sampling module for acquisition, thereby saving the hardware resources of the voltage sampling module, reducing the load of the voltage sampling module, and greatly reducing the cost. The method of differentially acquiring the load-end voltage of the power battery through the channel switching module can improve the circuit's anti-interference ability and effectively suppress EMI, thereby improving the signal acquisition accuracy.

[0030] Optional, such as Figure 1 As shown, the intelligent BDU voltage detection circuit also includes a differential amplifier module, which is connected between the output end of the channel switching module and the voltage sampling end of the voltage sampling module. The differential signal output by the channel switching module is respectively input into the two input ends of the differential amplifier module, and the output end of the differential amplifier module is connected to the voltage sampling end of the voltage sampling module.

[0031] like Figure 4 As shown, the preferred differential amplifier module of this embodiment is a differential amplifier circuit composed of a TS3211LT chip. In this embodiment, due to differential acquisition of the load terminal voltage of the power battery, there is interference from common-mode signals in the circuit, which will cause zero drift. The differential amplifier module can well suppress the common-mode input signal and amplify the differential-mode input signal. The influence of environmental factors such as temperature on the circuit can be input as a common-mode signal, which can effectively suppress the occurrence of zero drift.

[0032] Optional, such as Figure 1 As shown, the intelligent BDU voltage detection circuit also includes a voltage follower module, which is connected between the output end of the channel switching module and the two input ends of the differential amplifier module. The differential signal output by the channel switching module is respectively input into the two in-phase input ends of the voltage follower module, and the two output ends of the voltage follower module are respectively connected to the two input ends of the differential amplifier module in a one-to-one correspondence.

[0033] like Figure 5As shown, the preferred voltage follower module in this embodiment is a voltage follower circuit composed of an LM2904QS-13 chip. In this embodiment, the differential amplifier module is composed of an operational amplifier, and impedance matching is required for the positive and negative input terminals of the differential amplifier module, so as to offset the voltage drop caused by the offset current of the positive and negative input terminals and improve the output accuracy of the differential amplifier module.

[0034] Optional, such as Figure 6 As shown, the channel switching module includes a HEF4052B-Q100 chip; in the multi-channel voltage divider circuit, the output end of the first voltage divider circuit is connected to the 1Y2 pin of the HEF4052B-Q100 chip, the output end of the second voltage divider circuit is connected to the 1Y0 pin and the 1Y1 pin of the HEF4052B-Q100 chip at the same time, the output end of the third voltage divider circuit is connected to the 2Y1 pin of the HEF4052B-Q100 chip, and the output end of the fourth voltage divider circuit is connected to the 2Y2 pin of the HEF4052B-Q100 chip; the 1Z and 2Z pins of the HEF4052B-Q100 chip are respectively connected to the two in-phase input ends of the voltage follower module in a one-to-one correspondence.

[0035] In this embodiment, the output end of the channel switching module includes the 1Z and 2Z pins of the HEF4052B-Q100 chip, and the 1Z and 2Z pins of the HEF4052B-Q100 chip are respectively connected to the +INA pin and +INB pin of the LM2904QS-13 chip in a one-to-one correspondence, and the OUTA pin and OUTB pin of the LM2904QS-13 chip are respectively connected to the -INA pin and -INB pin of the LM2904QS-13 chip in a one-to-one correspondence. The differential amplifier module includes a TS3211LT chip, a resistor R109, a resistor R110, a resistor R111 and a resistor R112. The resistor R112 is connected in series with the resistor R111 and is grounded through R111. One end of the resistor R112 opposite to the resistor R111 is connected to the OUTA pin of the LM2904QS-13 chip. The common end of the resistor R112 and the resistor R111 is connected to the in-phase input end of the TS3211LT chip. The resistor R109 is connected in series with the resistor R110 and is connected to the output end of the TS3211LT chip through the resistor R110. The common end of the resistor R109 and the resistor R110 is connected to the inverting input end of the TS3211LT chip. One end of the resistor R109 opposite to the resistor R110 is connected to the OUTB pin of the LM2904QS-13 chip. The output end of the TS3211LT chip is connected to the PTR4 pin of the MM9Z1_638D1 chip.

[0036] Optionally, the output end of the power supply module is respectively connected to the power supply ends of the controller and the voltage sampling module, and the power supply end of the voltage sampling module is respectively connected to the power supply ends of the channel switching module, the voltage follower module and the differential amplifier module.

[0037] In this embodiment, the voltage output by the power supply module powers the controller and the voltage sampling module. In some cases, due to the selection of the channel switching module, the voltage following module and the differential amplifier module, the voltage output by the power supply module may not be able to directly power the channel switching module, the voltage following module and the differential amplifier module. Therefore, it is necessary to convert the voltage output by the power supply module into the supply voltage of the channel switching module, the voltage following module and the differential amplifier module through the voltage sampling module to solve the problem that the voltage output by the power supply module cannot directly power the channel switching module, the voltage following module and the differential amplifier module.

[0038] Optional, such as Figure 1 As shown, the intelligent BDU voltage detection circuit also includes an isolation transformer, which is connected between the output end of the power module and the power end of the voltage sampling module, and is used to convert the output voltage of the power module into the supply voltage of the voltage sampling module.

[0039] In some cases, due to the different selection of the power module and the voltage sampling module, the voltage output by the power module may not be able to directly power the voltage sampling module. For example, in this embodiment, the power module is MC33FS4500CAE chip, and the MC33FS4500CAE chip outputs 1 3.3V and 3 5V voltages. The voltage sampling module includes the MM9Z1_638D1 chip, and the power supply voltage required by the MM9Z1_638D1 chip is 6.5V, so the output voltage of the MC33FS4500CAE chip cannot directly power the MM9Z1_638D1 chip. Here, the power supply end of the voltage sampling module is the VSUP pin of the MM9Z1_638D1 chip. In this embodiment, the isolation transformer can be used to convert the output voltage of the power module into the power supply voltage of the voltage sampling module. For example, the 1:1.3 isolation transformer can convert the 5V voltage output by the MC33FS4500CAE chip into 6.5V, and then output 5V through the voltage sampling module to respectively power the channel switching module, the voltage follower module and the differential amplifier module.

[0040] Optional, such as Figure 1As shown, the intelligent BDU voltage detection circuit also includes a voltage reversal module, the input end of the voltage reversal module is connected to the power supply end of the voltage sampling module, the power supply end of the voltage sampling module is also respectively connected to the positive pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, the output end of the voltage reversal module is respectively connected to the negative pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, and the voltage reversal module is used to convert the positive voltage output by the power supply end of the voltage sampling module into a negative voltage.

[0041] In this embodiment, the channel switching module, the voltage follower module and the differential amplifier module are all powered by dual power supplies, so it is necessary to provide the negative power supply required by the above three module circuits. Here, the power supply end of the voltage sampling module is the VDDX pin and the VDDRX pin of the MM9Z1_638D1 chip. Figure 7 As shown, the voltage reversal module includes a TPS60401QDBVRQ1 chip, an IN pin of the TPS60401QDBVRQ1 chip is simultaneously connected to a VDDX pin and a VDDRX pin of the MM9Z1_638D1 chip, an OUT pin of the TPS60401QDBVRQ1 chip is respectively connected to a VDD pin of a HEF4052B-Q100 chip, a V+ pin of a LM2904QS-13 chip, and a positive power supply terminal of a TS3211LT chip, and a VDDX pin and a VDDRX pin of the MM9Z1_638D1 chip are also respectively connected to a VEE pin of a HEF4052B-Q100 chip, a V- pin of a LM2904QS-13 chip, and a negative power supply terminal of a TS3211LT chip.

[0042] Optionally, in the multi-channel voltage-dividing circuit of the intelligent BDU voltage detection circuit, multiple output ends of another part of the voltage-dividing circuit are directly connected to multiple voltage sampling ends of the voltage sampling module in a one-to-one correspondence.

[0043] Since there are 7 voltages at the load end of the power battery, generally, it is difficult for the channel switching module to meet the channel switching of the 7 input signals. For example, in this embodiment, the HEF4052B-Q100 chip can only provide switching of 4 input signals. One HEF4052B-Q100 chip cannot meet the channel switching of the 7 input signals, and increasing the number of HEF4052B-Q100 chips will increase the cost. In this embodiment, the other 3 load end voltages of the power battery are preferably directly input into the voltage sampling module, which will not increase the load of the voltage sampling module too much, and there is no need to increase the number of HEF4052B-Q100 chips. The combination of the two voltage acquisition methods reduces the cost while ensuring hardware resource conservation and low load.

[0044] Optionally, the intelligent BDU voltage detection circuit also includes a digital isolator, and the SPI port of the voltage sampling module is connected to the SPI port of the controller via the digital isolator. Specifically, the digital isolator includes an ISO7341CQDWRQ1 chip, and the B1 pin, B2 pin, B3 pin, and B4 pin of the ISO7341CQDWRQ1 chip are respectively connected to the SPI port of the voltage sampling module in a one-to-one correspondence, and the A1 pin, A2 pin, A3 pin, and A4 pin of the ISO7341CQDWRQ1 chip are respectively connected to the SPI port of the controller in a one-to-one correspondence. In this embodiment, the B1 pin, B2 pin, B3 pin, and B4 pin of the ISO7341CQDWRQ1 chip are respectively connected to the PA0 pin, PA2 pin, PA3 pin, and PA1 pin of the MM9Z1_638D1 chip, and the A1 pin, A2 pin, A3 pin, and A4 pin of the ISO7341CQDWRQ1 chip are respectively connected to the MOSI pin, SCK pin, CS pin, and MISO pin of the controller. The digital isolator is used to digitally isolate the communication between the voltage sampling module and the controller to prevent the circuits from being damaged when communicating with each other.

[0045] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An intelligent BDU voltage detection circuit, characterized in that: It includes a power supply module, a controller, a voltage sampling module, a multi-channel voltage dividing circuit, and a channel switching module; The controller is in communication connection with the voltage sampling module; the multiple input terminals of the multi-channel voltage-dividing circuit are respectively connected to the multiple load terminal voltages of the power battery; in the multi-channel voltage-dividing circuit, the multiple output terminals of some voltage-dividing circuits are respectively connected to the multiple input terminals of the channel switching module in a one-to-one correspondence; the output terminal of the channel switching module is connected to a voltage sampling terminal of the voltage sampling module, and the channel switching module is used to select one channel from the multiple output signals of the partial voltage-dividing circuit for differential output; It also includes a differential amplifier module, which is connected between the output end of the channel switching module and the voltage sampling end of the voltage sampling module, and the differential signal output by the channel switching module is respectively input into the two input ends of the differential amplifier module, and the output end of the differential amplifier module is connected to the voltage sampling end of the voltage sampling module; It also includes a voltage follower module, which is connected between the output end of the channel switching module and the two input ends of the differential amplifier module, and the differential signal output by the channel switching module is respectively input into the two in-phase input ends of the voltage follower module, and the two output ends of the voltage follower module are respectively connected to the two input ends of the differential amplifier module in a one-to-one correspondence; The output end of the power supply module is respectively connected to the controller and the power supply end of the voltage sampling module, and the power supply end of the voltage sampling module is respectively connected to the power supply end of the channel switching module, the voltage follower module and the differential amplifier module; In the multi-channel voltage-dividing circuit, a plurality of output terminals of another part of the voltage-dividing circuit are directly connected to a plurality of voltage sampling terminals of the voltage sampling module in a one-to-one correspondence.

2. The intelligent BDU voltage detection circuit according to claim 1, characterized in that: The channel switching module includes a HEF4052B-Q100 chip; in the multi-channel voltage divider circuit, the output end of the first voltage divider circuit is connected to the 1Y2 pin of the HEF4052B-Q100 chip, the output end of the second voltage divider circuit is connected to the 1Y0 pin and the 1Y1 pin of the HEF4052B-Q100 chip at the same time, the output end of the third voltage divider circuit is connected to the 2Y1 pin of the HEF4052B-Q100 chip, and the output end of the fourth voltage divider circuit is connected to the 2Y2 pin of the HEF4052B-Q100 chip; the 1Z and 2Z pins of the HEF4052B-Q100 chip are respectively connected to the two in-phase input ends of the voltage follower module in a one-to-one correspondence.

3. The intelligent BDU voltage detection circuit according to claim 1, characterized in that: It also includes an isolation transformer, which is connected between the output end of the power supply module and the power supply end of the voltage sampling module and is used to convert the output voltage of the power supply module into the power supply voltage of the voltage sampling module.

4. The intelligent BDU voltage detection circuit according to claim 1, characterized in that: It also includes a voltage reversal module, the input end of the voltage reversal module is connected to the power supply end of the voltage sampling module, the power supply end of the voltage sampling module is also respectively connected to the positive pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, the output end of the voltage reversal module is respectively connected to the negative pole of the power supply end of the channel switching module, the voltage following module and the differential amplifier module, and the voltage reversal module is used to convert the positive voltage output by the power supply end of the voltage sampling module into a negative voltage.

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