High-precision current detection system for composite multi-parameter sensor chip

Abstract

The invention discloses a high-precision current detection system for a composite multi-parameter sensor chip, and the system comprises a housing, the housing is provided with a connector and a diverter, the interior of the housing is provided with a PCBA board, and the interior of the PCBA board is provided with a current detection module. The current detection module comprises a power supply circuit, a signal isolation circuit, an MCU, a data memory and a temperature monitoring sensor. The ADC sampling end of the MUC is connected with the diverter, the temperature control input end of the MUC is connected with the temperature monitoring sensor, and the temperature monitoring sensor is used for monitoring and detecting the temperature of the diverter; a communication port of the MUC is connected with a data storage device, and current calibration parameters at different temperatures are stored in the data storage device; the power supply input end of the MCU is connected with the power supply circuit through the signal isolation circuit; the power supply circuit is connected with the connector; and a sliding filtering algorithm and a temperature compensation algorithm are arranged in the MCU. The current detection of the composite multi-parameter sensor chip can be met, and the method has the advantage of high precision.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor electronic devices, and in particular to a high-precision current detection system for a composite multi-parameter sensor chip. Background Art

[0002] With the rapid development of new-generation information technologies such as the Internet of Things and big data, silicon-based multimodal sensing chips and devices, as the perception and monitoring of various basic physical information, such as pressure, flow, temperature, conductivity and other physical quantities, play an irreplaceable role in various intelligent hardware and devices. Especially in the field of fluid pumping, sensing and actuator devices are key components, and their detection sensitivity and stability directly determine the reliability and service life of the pumping system. The multi-parameter sensor chip that integrates pressure, temperature, flow and inductance signal observation will realize the functions of autonomous pressure learning, small flow observation, efficient motor operation and fault diagnosis of the pumping system, solving the problems of sensitivity, stability and nonlinearity of sensing devices in the pumping system and low processing yield.

[0003] At present, there are two main methods for current detection modules for composite multi-parameter sensor chips, namely, shunt sheet detection method and Hall current detection method. The shunt sheet is a milliohm resistor made of alloys such as manganese copper. The battery management system detects the voltage across the shunt sheet and calculates the corresponding current value according to Ohm's law. This method is low in cost, poor in accuracy, greatly affected by ambient temperature, and requires the battery management system to design a signal detection circuit interface. The current detection using the current Hall sensor calculates the bus current by connecting to the ADC detection port on the battery management system. This method is costly and also requires the battery management system to reserve a dedicated external interface. Summary of the invention

[0004] The purpose of the present invention is to provide a high-precision current detection system for a composite multi-parameter sensor chip. The present invention can meet the current detection of a composite multi-parameter sensor chip and has the advantage of high precision.

[0005] The technical scheme of the present invention is as follows: a high-precision current detection system for a composite multi-parameter sensor chip, comprising a shell, a connector and a shunt are arranged on the shell, a PCBA board is arranged inside the shell, and a current detection module is arranged in the PCBA board; the current detection module comprises a power supply circuit, a signal isolation circuit, an MCU, a data storage and a temperature monitoring sensor; the ADC sampling end of the MUC is connected to the shunt, the temperature control input end of the MUC is connected to the temperature monitoring sensor, and the temperature monitoring sensor is used to monitor and detect the temperature of the shunt; the communication port of the MUC is connected to the data storage, and the data storage stores current calibration parameters at different temperatures; the power input end of the MCU is connected to the power circuit via the signal isolation circuit; the power circuit is connected to the connector; a sliding filter algorithm and a temperature compensation algorithm are arranged in the MCU; the MCU collects voltage information on the shunt through the ADC sampling end, eliminates pulse interference in ADC sampling through the sliding filter algorithm, and then calibrates the collected voltage signal according to the current calibration parameters using the temperature compensation algorithm to ensure the measurement accuracy of the current.

[0006] The above-mentioned high-precision current detection system for the composite multi-parameter sensor chip, the sliding filter algorithm comprises the following steps:

[0007] Step 1: Get ADC sampling value;

[0008] Step 2: Fill the ADC sampling values ​​into the array. Each array stores 16 ADC values ​​[ADC1,,,ADC 16 ];

[0009] Step 3: Remove the maximum and minimum values ​​in the array;

[0010] Step 4: Calculate the average ADC avg ;

[0011] Step 5: Fill the array with the newly acquired ADC;

[0012] Step 6: Repeat steps 2 to 5 until the ADC sampling is completed.

[0013] The high-precision current detection system for the aforementioned composite multi-parameter sensor chip, the temperature compensation algorithm comprises the following steps:

[0014] Step a: Use a temperature monitoring sensor to monitor the temperature value of the shunt plate in real time;

[0015] Step b: Obtain the resistance value R at both ends of the shunt sheet at the actual ambient temperature;

[0016] Step c: Read the voltage ADC sampling value x across the shunt chip;

[0017] Step d: Calculate the current value y according to the ADC sampling voltage and the resistance value R at both ends of the shunt chip;

[0018] Step e: Determine the calibration interval [0,30A], [0,150A], [0,350A] according to the current value;

[0019] Step f: Call the interval current calibration parameters [k i ,b i ];

[0020] Step g: Substitute the current calibration parameters of the corresponding interval into the formula: y'=k i x+b i , calculate the output calibrated current value y'.

[0021] The aforementioned high-precision current detection system for the composite multi-parameter sensor chip, the PCBA board is provided with a CAN communication circuit, one end of the CAN communication circuit is connected to the signal isolation circuit, and the other end of the CAN communication circuit is connected to the connector, and the CAN communication circuit realizes the interaction between the current detection module and the outside world.

[0022] The aforementioned high-precision current detection system for the composite multi-parameter sensor chip, the PCBA board is provided with a hardware trigger circuit, one end of the hardware trigger circuit is connected to the signal isolation circuit, and the other end of the hardware trigger circuit is connected to the connector.

[0023] The aforementioned high-precision current detection system for the composite multi-parameter sensor chip, wherein the PCBA board is provided with a fault feedback circuit, one end of the fault feedback circuit is connected to the signal isolation circuit, and the other end of the fault feedback circuit is connected to the connector.

[0024] The aforementioned high-precision current detection system for the composite multi-parameter sensor chip, the power supply circuit is composed of a power board chip MPQ2459GJ and a filter.

[0025] The aforementioned high-precision current detection system for the composite multi-parameter sensor chip, wherein the MCU is a microcontroller MM9Z1J638.

[0026] The aforementioned composite multi-parameter sensor chip uses a high-precision current detection system, and the isolation circuit sampling isolation chip ADuM6402.

[0027] The aforementioned composite multi-parameter sensor chip uses a high-precision current detection system, and the data storage device uses an EEPROMM24C64 memory.

[0028] Compared with the prior art, the present invention can eliminate the pulse interference in ADC sampling by using a sliding filter algorithm, and then calibrate the collected voltage signal through a temperature compensation algorithm, thereby solving the measurement error caused by the change of the shunt plate's own temperature during operation, and ensuring the current measurement accuracy. The present invention has good circuit anti-interference ability, can adapt to high-precision measurement of different load currents, with an error of less than 0.5%, and has strong stability in practical applications. In addition, the current data of the present invention can be directly read through the CAN bus, saving hardware resources for current detection of the battery management system, reducing the cost of the battery management system, and meeting the current acquisition accuracy requirements at different operating temperatures, with good working stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the system of the present invention;

[0030] Figure 2 It is a diagram of the explosion state of the system of the present invention;

[0031] Figure 3 This is a system block diagram of the current detection module in the present invention;

[0032] Figure 4 This is an application circuit diagram of the current detection module in the present invention;

[0033] Figure 5 It is the main program flow chart of the present invention;

[0034] Figure 6 This is a flow chart of the sliding filtering algorithm in the present invention;

[0035] Figure 7 This is a flowchart of the fast compensation algorithm program in the present invention;

[0036] Reference numerals

[0037] 1-upper cover; 2-PCBA; 3-bottom shell; 4-shunt sheet. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention. The protection scope of the present invention should include the entire content of the claims, and the following embodiments can enable ordinary technicians in the field to more fully understand the present invention.

[0039] Embodiment: A high-precision current detection system for a composite multi-parameter sensor chip, such as Figure 1 and Figure 2As shown, it includes a housing 3, on which a connector 5 and a shunt 4 are arranged. The connector is used as a port for connecting to the BMS, and the shunt 4 is used for connecting to the load and the battery. A PCBA board is arranged inside the housing 3, and a current detection module is arranged in the PCBA board. Figure 3 As shown, the current detection module includes a power supply circuit, a signal isolation circuit, an MCU, a data storage device and a temperature monitoring sensor; the ADC sampling end of the MUC is connected to the shunt, and the temperature control input end of the MUC is connected to the temperature monitoring sensor, and the temperature monitoring sensor is used to monitor and detect the temperature of the shunt; the communication port of the MUC is connected to the data storage device, and the data storage device stores current calibration parameters at different temperatures; the power input end of the MCU is connected to the power supply circuit via the signal isolation circuit; the power supply circuit is connected to the connector; a sliding filter algorithm and a temperature compensation algorithm are provided in the MCU; the MCU collects the voltage information on the shunt through the ADC sampling end, eliminates the pulse interference in the ADC sampling through the sliding filter algorithm, and then calibrates the collected voltage signal according to the current calibration parameters using the temperature compensation algorithm to ensure the current measurement accuracy.

[0040] In this embodiment, the power supply circuit supplies power to the current detection module through the vehicle-mounted 12V / 24VDC power supply interface; the internal control system power supply is a step-down power supply circuit composed of the power board chip MPQ2459GJ (step-down converter), which realizes the step-down process of 12V to 5V, and then the 5V input is used to supply power to the MCU through the isolated ISO_5V power supply to the signal isolation circuit.

[0041] The MCU is a 32-bit microcontroller MM9Z1J638BM2EP with floating-point operation function. It has a built-in high-speed 16-bit high-precision ADC sampling circuit. The main function of this circuit is to quickly sample high-speed input signals. The maximum adoption rate is determined by the sampling speed of the ADC. This MCU chip implements the signal input detection function of this module, can realize CAN communication, and communicate with the data storage EEPROM through I2C.

[0042] The data memory is M24C64-DRMN3TP / K, which has 64Kbit of storage space. Its main function in this circuit is to obtain calibration parameter values ​​in different current ranges.

[0043] Signal isolation circuit: ADuM6402 chip is mainly used to achieve signal isolation. Its function is to isolate the high voltage on the battery side and reduce the impact of high voltage introduction on the vehicle communication side. It can meet the maximum isolation withstand voltage of 5000V.

[0044] The PCBA board is provided with a CAN communication circuit, one end of the CAN communication circuit is connected to the signal isolation circuit, and the other end of the CAN communication circuit is connected to the connector. The CAN communication circuit realizes the interaction between the current detection module and the outside world. The CAN communication circuit uses the TJA1051T chip for the CAN communication transceiver converter, which mainly realizes the information interaction between the current detection module and the BMS, and sends the current information to the battery management system or the whole vehicle. The CAN communication rate can be adapted to 250kbit / s or 500kbits / s.

[0045] The PCBA board is provided with a hardware trigger circuit, one end of the hardware trigger circuit is connected to the signal isolation circuit, and the other end of the hardware trigger circuit is connected to the connector. The hardware trigger circuit mainly adopts resistors, capacitors and TVS tubes to form a hardware trigger circuit, which is set to a 5V high-level signal by default. When a hardware low-level signal is connected, the MCU port will detect the low-level signal as a detection result and transmit the signal to the whole vehicle through CAN communication.

[0046] The PCBA board is provided with a fault feedback circuit, one end of which is connected to the signal isolation circuit, and the other end of which is connected to the connector. The fault feedback circuit mainly uses resistors, capacitors and transistor drive outputs. When the current detection module is abnormal, a fault feedback signal is sent from the MCU port. The output signal passes through the isolation chip ADuM6402, drives the transistor drive circuit, and generates a low-level signal to the connector port.

[0047] like Figure 4 As shown in the figure, this is the application block diagram of this system. The current detection module is connected to the negative pole of the battery pack, because the voltage difference between the sampling points at both ends of the shunt sheet is an mv signal, and its voltage to ground is determined by the measured circuit. The negative pole of the battery pack is grounded and connected to the negative pole of the high-voltage battery pack of the current detection module. Its voltage to ground is very low, which has a good protective effect on the insulation withstand voltage of the current detection module and the safety of the operator.

[0048] like Figure 5 As shown in the figure, this is the main program flow chart of this system. The program functions mainly include 6 categories: power-on system self-test program, interrupt trigger program, CAN communication status recognition program, ADC calibration program, sliding filter algorithm program, and fast compensation algorithm program.

[0049] like Figure 6 The ADC acquisition sliding filter algorithm is shown. Due to the influence of the vehicle environment, the ADC sampling of the current will be accompanied by some interference noise data, so that the actual sampled data is not the real current data, and a certain method must be used to eliminate the error. The present invention provides a sliding filter algorithm, which mainly includes the following steps:

[0050] Step 1: Get ADC sampling value;

[0051] Step 2: Fill the ADC sampling values ​​into the array. Each array stores 16 ADC values ​​[ADC1,,,ADC 16 ];

[0052] Step 3: Remove the maximum and minimum values ​​in the array;

[0053] Step 4: Calculate the average ADC avg ;

[0054] Step 5: Fill the array with the newly acquired ADC;

[0055] Step 6: Repeat steps 2 to 5 until the ADC sampling is completed.

[0056] The sliding filter algorithm of the present invention is composed of data acquisition and transformation. The control system acquires data in groups of N data, removes the maximum value and the minimum value, applies the algorithm to ADC to sample N values, removes the maximum value and the minimum value, calculates the average value of N-2, and then recursively fills and updates the array in real time through ADC acquisition. This method can eliminate pulse interference and avoid current detection abnormality due to the introduction of interference.

[0057] Figure 7 : is a flow chart of the temperature compensation algorithm of the present invention. Since the resistance value of the shunt sheet is affected by the change of temperature, if the current value is calculated in a fixed resistance value manner, there will be a large error. The present invention provides a temperature compensation algorithm for the current detection module, which mainly includes the following steps:

[0058] Step a: Use a temperature monitoring sensor to monitor the temperature value of the shunt plate in real time;

[0059] Step b: Obtain the resistance value R at both ends of the shunt sheet at the actual ambient temperature;

[0060] Step c: Read the voltage ADC sampling value x across the shunt chip;

[0061] Step d: Calculate the current value y according to the ADC sampling voltage and the resistance value R at both ends of the shunt chip;

[0062] Step e: Determine the calibration interval [0,30A], [0,150A], [0,350A] according to the current value;

[0063] Step f: Call the interval current calibration parameters [k i ,b i ];

[0064] Step g: Substitute the current calibration parameters of the corresponding interval into the formula: y'=k i x+b i , calculate the output calibrated current value y'.

[0065] The temperature compensation algorithm of the present invention solves the measurement error caused by the change of the temperature of the shunt plate during operation by calibrating the collected voltage signal, thereby ensuring the measurement accuracy of the current, and the electrical detection accuracy can reach ±0.5%.

[0066] In summary, the present invention can meet the needs of composite multi-parameter sensor chip current detection and has the advantage of high precision. The present invention has good circuit anti-interference ability, can adapt to high-precision measurement of different load currents, with an error of less than 0.5%, and has strong stability in practical applications.

Claims

1. A high-precision current detection system for a composite multi-parameter sensor chip, comprising a housing, a connector and a shunt are arranged on the housing, and a PCBA board is arranged inside the housing, characterized in that: A current detection module is provided in the PCBA board; the current detection module includes a power supply circuit, a signal isolation circuit, an MCU, a data storage device and a temperature monitoring sensor; the ADC sampling end of the MUC is connected to the shunt, and the temperature control input end of the MUC is connected to the temperature monitoring sensor, and the temperature monitoring sensor is used to monitor and detect the temperature of the shunt; the communication port of the MUC is connected to the data storage device, and the data storage device stores current calibration parameters at different temperatures; the power input end of the MCU is connected to the power supply circuit via the signal isolation circuit; the power supply circuit is connected to the connector; a sliding filter algorithm and a temperature compensation algorithm are provided in the MCU; the MCU collects the voltage information on the shunt through the ADC sampling end, eliminates the pulse interference in the ADC sampling through the sliding filter algorithm, and then calibrates the collected voltage signal according to the current calibration parameters using the temperature compensation algorithm to ensure the current measurement accuracy.

2. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The sliding filter algorithm comprises the following steps: Step 1: Get ADC sampling value; Step 2: Fill the ADC sampling values ​​into the array. Each array stores 16 ADC values ​​[ADC1,,,ADC 16 ]; Step 3: Remove the maximum and minimum values ​​in the array; Step 4: Calculate the average ADC avg ; Step 5: Fill the array with the newly acquired ADC; Step 6: Repeat steps 2 to 5 until the ADC sampling is completed.

3. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The temperature compensation algorithm comprises the following steps: Step a: Use a temperature monitoring sensor to monitor the temperature value of the shunt plate in real time; Step b: Obtain the resistance value R at both ends of the shunt sheet at the actual ambient temperature; Step c: Read the voltage ADC sampling value x across the shunt chip; Step d: Calculate the current value y according to the ADC sampling voltage and the resistance value R at both ends of the shunt chip; Step e: Determine the calibration interval [0,30A], [0,150A], [0,350A] according to the current value; Step f: Call the interval current calibration parameters [k i ,b i ]; Step g: Substitute the current calibration parameters of the corresponding interval into the formula: y'=k i x+b i , calculate the output calibrated current value y'.

4. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The PCBA board is provided with a CAN communication circuit, one end of the CAN communication circuit is connected to the signal isolation circuit, and the other end of the CAN communication circuit is connected to the connector. The CAN communication circuit realizes the interaction between the current detection module and the outside world.

5. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The PCBA board is provided with a hardware trigger circuit, one end of the hardware trigger circuit is connected to the signal isolation circuit, and the other end of the hardware trigger circuit is connected to the connector.

6. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The PCBA board is provided with a fault feedback circuit, one end of the fault feedback circuit is connected to the signal isolation circuit, and the other end of the fault feedback circuit is connected to the connector.

7. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The power supply circuit is composed of a power board chip MPQ2459GJ and a filter.

8. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The MCU is a microcontroller MM9Z1J638.

9. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The isolation circuit described above is a sampling isolation chip ADuM6402.

10. The high-precision current detection system for a composite multi-parameter sensor chip according to claim 1, characterized in that: The data storage device adopts EEPROMM24C64 memory.

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