Current sampling circuit of shunt
By designing the shunt current sampling circuit and the temperature sampling circuit, the problems of low accuracy and high cost of Hall sensor current sampling are solved, and high accuracy and low cost of current sampling effects are achieved.
Patent Information
- Application Number
- CN202420828386.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-22
- Publication Date
- 2025-04-29
- Estimated Expiration
- 2034-04-22
AI Technical Summary
The existing power battery current sampling method uses Hall sensors, and the sensitivity may be reduced due to changes in magnetic field, temperature and power supply voltage, resulting in low sampling accuracy and high cost.
A shunt current sampling circuit is designed, including a shunt, a current sampling circuit, a CAN communication circuit, a MCU circuit, a power supply circuit and a temperature sampling circuit. The shunt is used to sample the current through the current sampling circuit, and combined with a temperature sampling circuit to assist in sampling to improve accuracy.
High-precision current sampling is achieved, reducing structural complexity and cost. At the same time, through temperature sampling assistance, the sampling environment is further ensured and the sampling accuracy is improved.
Smart Images
Figure CN222812883U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electricity, and more specifically to a shunt current sampling circuit. Background Art
[0002] As an important parameter in the power battery management process, the current collection scheme affects the system cost and collection accuracy. The collection accuracy directly affects the accuracy of SOC and the protection of the battery system, and indirectly affects the vehicle's range and user experience.
[0003] The current sampling of existing power batteries is mostly detected by Hall sensor circuits. Its working principle is that when current passes through a conductor, when the conductor is subjected to an external magnetic field, the charge carriers inside the conductor are affected by the Lorentz force, causing the charge carriers to deviate inside the conductor, resulting in electrons being concentrated on the side of the conductor, thereby generating a transverse voltage difference, namely the Hall voltage. By measuring the change in the Hall voltage, the change in the magnetic field can be obtained.
[0004] In the above process, the sensitivity of the Hall sensor may be reduced due to various reasons, such as changes in magnetic field strength, temperature changes, unstable power supply voltage, etc. Therefore, the sampling using the Hall sensor circuit cannot guarantee high accuracy and has high cost.
[0005] In view of this, the utility model proposes a current sampling circuit for a shunt which has accurate sampling and simple structure. Utility Model Content
[0006] The utility model aims to provide a current sampling circuit for a shunt with accurate sampling and simple structure.
[0007] A shunt current sampling circuit comprises a shunt, a current sampling circuit, a CAN communication circuit, an MCU circuit, a power supply circuit, and a communication interface, wherein the output end of the shunt is connected to an input end of the current sampling circuit, the output end of the current sampling circuit is connected to an input end of the MCU circuit, the MCU circuit is bidirectionally connected to the communication interface via the CAN communication circuit, the MCU circuit is bidirectionally connected to the program burning interface, the power supply circuit is connected to the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, the current sampling circuit is used to sample the current of the shunt and output the value to the MCU circuit, the CAN communication circuit is used to convert data into a differential signal for transmission and reception, the power supply circuit is used to provide power for the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, and the program burning interface is used to burn or / and read the control program in the MCU chip U1.
[0008] Furthermore, a temperature sampling circuit is provided between the shunt and the MCU circuit. The temperature sampling circuit is used to sample the temperature of the shunt and output the numerical value to the MCU circuit. The temperature sampling circuit includes a first temperature sampling circuit and a second temperature sampling circuit. The first temperature sampling circuit and the second temperature sampling circuit are provided between the shunt and the MCU circuit in sequence. When one of the first temperature sampling circuit and the second temperature sampling circuit detects an abnormal temperature, the MCU circuit outputs the data to the outside through the CAN communication circuit and the communication interface.
[0009] Furthermore, the first temperature sampling circuit includes a resistor R9 and a negative temperature coefficient thermistor RT1. One end of the shunt side is connected to pin 37 of the MCU chip U1 through the negative temperature coefficient thermistor RT1. The negative temperature coefficient thermistor RT1 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT1 is smaller. A resistor R9 is provided between the shunt and the negative temperature coefficient thermistor RT1, and the resistor R9 acts as a voltage divider.
[0010] Furthermore, the second temperature sampling circuit includes a resistor R10 and a negative temperature coefficient thermistor RT2. The other end of the shunt side is connected to pin 38 of the MCU chip U1 through the negative temperature coefficient thermistor RT2. The negative temperature coefficient thermistor RT2 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT2 is smaller. A resistor R10 is provided between the shunt side and the negative temperature coefficient thermistor RT2, and the resistor R10 acts as a voltage divider.
[0011] Furthermore, a resistor R11 is provided between the negative temperature coefficient thermistor RT1 and pin 37 of the MCU chip U1, and a resistor R12 is provided between the negative temperature coefficient thermistor RT2 and pin 38 of the MCU chip U1 to play a current limiting role. Both the resistor R11 and the resistor R12 play a current limiting role.
[0012] In some embodiments, the current sampling circuit includes a resistor R7, a resistor R8, a capacitor C11, and a capacitor C12. A resistor R7 is provided between pin 1 of the shunt SR1 and pin 31 of the MCU chip U1, and a resistor R8 is provided between pin 2 of the shunt SR1 and pin 30 of the MCU chip U1. The resistors R7 and R8 serve to protect the MCU chip U1. A capacitor C11 and a capacitor C12 are provided between the resistors R7 and R8. One ends of the capacitors C11 and C12 are connected to the capacitors C11 and C12, and the other ends of the capacitors C11 and C12 are grounded. The capacitors C11 and C12 are common-mode capacitors, which serve to filter and eliminate common-mode interference.
[0013] Furthermore, a capacitor C13 is provided between the resistor R7 and the resistor R8. The capacitor C13 is a differential mode capacitor and plays a role in filtering and eliminating differential mode interference.
[0014] In some embodiments, the CAN communication circuit includes a transceiver chip U2, an inductor L1, a resistor R4, a resistor R5, and a TVS diode group D2. Pin 5 of the MCU chip U1 is connected to pin 1 of the transceiver chip U2, pin 6 of the MCU chip U1 is connected to pin 4 of the transceiver chip U2, pins 7 and 6 of the transceiver chip U2 are both connected to the communication interface, and inductor L1, resistor R4, resistor R5, and TVS diode group D2 are arranged in sequence between pins 7 and 6 of the transceiver chip U2 and the communication interface. Resistors R4 and R5 are terminal resistors, and resistors R4 and R5 play a role in eliminating signal reflections in the communication cable. The capacitors C9 and C10 are common-mode capacitors, which play a role in filtering and eliminating common-mode interference, and the TVS diode group D2 plays an anti-static role.
[0015] In some implementations, the MCU circuit is also connected to a crystal oscillator circuit, which consists of a capacitor C14, a capacitor C15, and a crystal oscillator Y1. The crystal oscillator circuit provides the MCU chip U1 with the required precise reference frequency or stable clock signal.
[0016] In some embodiments, the program burning interface includes an interface J2, and pin 4 of interface J2 is connected to pin 46 of the MCU chip U1; the communication interface includes an interface J1, and pin 4 of the interface J1 is connected to pin 7 of the transceiver chip U2, and pin 3 of the interface J1 is connected to pin 6 of the transceiver chip U2.
[0017] Beneficial effects of the utility model: the utility model proposes a shunt current sampling circuit, the shunt output end is connected to the current sampling circuit input end, the current sampling circuit output end is connected to an input end of an MCU circuit, the MCU circuit is bidirectionally connected to the communication interface via a CAN communication circuit, the MCU circuit is bidirectionally connected to the program burning interface, the power supply circuit is connected to the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, the current sampling circuit is used to sample the current of the shunt and output the numerical value to the MCU circuit, the CAN communication circuit is used to convert the data into a differential signal for transmission and reception, the current is sampled by setting the current sampling circuit, and the first temperature sampling circuit and the second temperature sampling circuit are set to perform temperature sampling, auxiliary current sampling, prevent one of the first temperature sampling circuit and the second temperature sampling circuit from failing, further ensure the current sampling environment, improve the sampling accuracy, simple structure, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 A circuit diagram of a power supply circuit of a shunt current sampling circuit of the present application.
[0019] Figure 2 A circuit diagram of a current sampling circuit of a shunt current sampling circuit of the present application.
[0020] Figure 3 A circuit diagram of a temperature sampling circuit of a shunt current sampling circuit of the present application.
[0021] Figure 4 A circuit diagram of an MCU circuit of a shunt current sampling circuit of the present application.
[0022] Figure 5 A circuit diagram of a CAN communication circuit of a shunt current sampling circuit of the present application.
[0023] Figure 6 A circuit diagram of a communication interface of a shunt current sampling circuit of the present application.
[0024] Figure 7 A circuit diagram of a program burning interface of a shunt current sampling circuit of the present application.
[0025] Figure 8 A circuit diagram of a crystal oscillator circuit of a shunt current sampling circuit of the present application.
[0026] The following specific implementation manner will further illustrate the present utility model in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0027] The following examples are described to assist the understanding of the present application, and the examples are not and should not be interpreted in any way as limiting the scope of protection of the present application.
[0028] In the following description, those skilled in the art will recognize that throughout this discussion, components may be described as separate functional units (which may include sub-units), but those skilled in the art will recognize that various components or portions thereof may be divided into separate components or may be integrated together (including within a single system or component).
[0029] At the same time, the connections between components or systems are not intended to be limited to direct connections, rather, the data between these components may be modified, reformatted, or otherwise changed by intermediate components. In addition, additional or fewer connections may be used. It should also be noted that the terms "coupled," "connected," or "input" should be understood to include direct connections, indirect connections through one or more intermediate devices, and wireless connections.
[0030] Embodiment 1:
[0031] like Figure 1 As shown, it is a circuit diagram of a power supply circuit of a shunt current sampling circuit of the present application; Figure 2 As shown, it is a circuit diagram of a current sampling circuit of a shunt current sampling circuit of the present application; Figure 3 As shown, it is a circuit diagram of a temperature sampling circuit of a shunt current sampling circuit of the present application; Figure 4 As shown, it is a circuit diagram of an MCU circuit of a shunt current sampling circuit of the present application; Figure 5 As shown, it is a circuit diagram of a CAN communication circuit of a shunt current sampling circuit of the present application; Figure 6 As shown, it is a circuit diagram of a communication interface of a shunt current sampling circuit of the present application; Figure 7 As shown in FIG. 1 , it is a circuit diagram of a program burning interface of a shunt current sampling circuit of the present application; Figure 8 , which is a circuit diagram of a crystal oscillator circuit of a shunt current sampling circuit of the present application.
[0032] A shunt current sampling circuit comprises a shunt, a current sampling circuit, a CAN communication circuit, an MCU circuit, a power supply circuit, a communication interface, and a program burning interface, wherein the output end of the shunt is connected to an input end of the current sampling circuit, the output end of the current sampling circuit is connected to an input end of the MCU circuit, the MCU circuit is bidirectionally connected to the communication interface via the CAN communication circuit, the MCU circuit is bidirectionally connected to the program burning interface, the power supply circuit is connected to the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, the current sampling circuit is used to sample the current of the shunt and output the value to the MCU circuit, the CAN communication circuit is used to convert data into a differential signal for transmission and reception, the power supply circuit is used to provide power for the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit connection, the program burning interface is used to burn or / and read the control program in the MCU chip U1, and the MCU chip U1 model is MM9Z1J638BM2EP.
[0033] As described, a temperature sampling circuit is also provided between the shunt and the MCU circuit. The temperature sampling circuit is used to sample the temperature of the shunt and output the value to the MCU circuit. The temperature sampling circuit includes a first temperature sampling circuit and a second temperature sampling circuit. The first temperature sampling circuit and the second temperature sampling circuit are provided between the shunt and the MCU circuit in sequence. When one of the first temperature sampling circuit and the second temperature sampling circuit detects an abnormal temperature, the MCU circuit outputs the data to the outside through the CAN communication circuit and the communication interface.
[0034] The first temperature sampling circuit includes a resistor R9 and a negative temperature coefficient thermistor RT1. One end of the shunt side is connected to pin 37 of the MCU chip U1 through the negative temperature coefficient thermistor RT1. The negative temperature coefficient thermistor RT1 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT1 is smaller. A resistor R9 is provided between the shunt and the negative temperature coefficient thermistor RT1, and the resistor R9 plays a voltage divider role.
[0035] The second temperature sampling circuit includes a resistor R10 and a negative temperature coefficient thermistor RT2. The other end of the shunt side is connected to pin 38 of the MCU chip U1 through the negative temperature coefficient thermistor RT2. The negative temperature coefficient thermistor RT2 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT2 is smaller. A resistor R10 is provided between the shunt side and the negative temperature coefficient thermistor RT2, and the resistor R10 plays a voltage divider role.
[0036] A resistor R11 is provided between the negative temperature coefficient thermistor RT1 and the 37th pin of the MCU chip U1, and a resistor R12 is provided between the negative temperature coefficient thermistor RT2 and the 38th pin of the MCU chip U1 to play a current limiting role. Both the resistor R11 and the resistor R12 play a current limiting role.
[0037] The current sampling circuit includes a resistor R7, a resistor R8, a capacitor C11, and a capacitor C12. A resistor R7 is provided between pin 1 of the shunt SR1 and pin 31 of the MCU chip U1. A resistor R8 is provided between pin 2 of the shunt SR1 and pin 30 of the MCU chip U1. The resistors R7 and R8 play a role in protecting the MCU chip U1. A capacitor C11 and a capacitor C12 are provided between the resistors R7 and R8. One ends of the capacitors C11 and C12 are connected to the capacitors C11 and C12, and the other ends of the capacitors C11 and C12 are grounded. The capacitors C11 and C12 are common-mode capacitors, which play a role in filtering and eliminating common-mode interference.
[0038] A capacitor C13 is further disposed between the resistors R7 and R8. The capacitor C13 is a differential mode capacitor and plays a role in filtering and eliminating differential mode interference.
[0039] The model of the transceiver chip U2 is TJA1042T / 3 / 1J. The CAN communication circuit includes the transceiver chip U2, an inductor L1, a resistor R4, a resistor R5, and a TVS diode group D2. Pin 5 of the MCU chip U1 is connected to pin 1 of the transceiver chip U2, and pin 6 of the MCU chip U1 is connected to pin 4 of the transceiver chip U2. Pins 7 and 6 of the transceiver chip U2 are both connected to the communication interface. Inductor L1, resistor R4, resistor R5, and TVS diode group D2 are arranged in sequence between pins 7 and 6 of the transceiver chip U2 and the communication interface. Resistors R4 and R5 are terminal resistors. Resistors R4 and R5 play a role in eliminating signal reflections in the communication cable. Capacitors C9 and C10 are common-mode capacitors that play a role in filtering and eliminating common-mode interference. The TVS diode group D2 plays an anti-static role.
[0040] The MCU circuit is also connected to a crystal oscillator circuit, which consists of a capacitor C14, a capacitor C15, and a crystal oscillator Y1. The crystal oscillator circuit provides the MCU chip U1 with the required precise reference frequency or stable clock signal.
[0041] The program burning interface includes an interface J2, and pin 4 of the interface J2 is connected to pin 46 of the MCU chip U1; the communication interface includes an interface J1, and pin 4 of the interface J1 is connected to pin 7 of the transceiver chip U2, and pin 3 of the interface J1 is connected to pin 6 of the transceiver chip U2.
[0042] Beneficial effects of the utility model: the utility model proposes a shunt current sampling circuit, the shunt output end is connected to the current sampling circuit input end, the current sampling circuit output end is connected to an input end of an MCU circuit, the MCU circuit is bidirectionally connected to the communication interface via a CAN communication circuit, the MCU circuit is bidirectionally connected to the program burning interface, the power supply circuit is connected to the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, the current sampling circuit is used to sample the current of the shunt and output the numerical value to the MCU circuit, the CAN communication circuit is used to convert the data into a differential signal for transmission and reception, the current is sampled by setting the current sampling circuit, and the first temperature sampling circuit and the second temperature sampling circuit are set to perform temperature sampling, auxiliary current sampling, prevent one of the first temperature sampling circuit and the second temperature sampling circuit from failing, further ensure the current sampling environment, improve the sampling accuracy, simple structure, and low cost.
[0043] Although the present application has disclosed multiple aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art, and several modifications and improvements may be made without departing from the concept of the present application, all of which belong to the protection scope of the present application. The multiple aspects and embodiments disclosed in the present application are only for illustration and are not intended to limit the present application. The actual protection scope of the present application shall be subject to the claims.
Claims
1. A shunt current sampling circuit, comprising a shunt, a current sampling circuit, a CAN communication circuit, an MCU circuit, a power supply circuit, a communication interface, and a program burning interface, characterized in that: The output end of the shunt is connected to the input end of the current sampling circuit, the output end of the current sampling circuit is connected to an input end of the MCU circuit, the MCU circuit is bidirectionally connected to the communication interface through the CAN communication circuit, the MCU circuit is bidirectionally connected to the program burning interface, the power supply circuit is connected to the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit, the current sampling circuit is used to sample the current of the shunt and output the value to the MCU circuit, the CAN communication circuit is used to convert the data into a differential signal for transmission and reception, the power supply circuit is used to provide power for the shunt, the current sampling circuit, the CAN communication circuit, and the MCU circuit connection, and the program burning interface is used to burn or / and read the control program in the MCU chip U1.
2. The shunt current sampling circuit according to claim 1, characterized in that: A temperature sampling circuit is also provided between the shunt and the MCU circuit. The temperature sampling circuit is used to sample the shunt temperature and output the value to the MCU circuit. The temperature sampling circuit includes a first temperature sampling circuit and a second temperature sampling circuit. The first temperature sampling circuit and the second temperature sampling circuit are provided between the shunt and the MCU circuit in sequence.
3. The shunt current sampling circuit according to claim 2, characterized in that: The first temperature sampling circuit includes a resistor R9 and a negative temperature coefficient thermistor RT1. One end of the shunt side is connected to pin 37 of the MCU chip U1 through the negative temperature coefficient thermistor RT1. The negative temperature coefficient thermistor RT1 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT1 is smaller. A resistor R9 is provided between the shunt and the negative temperature coefficient thermistor RT1, and the resistor R9 plays a voltage divider role.
4. The shunt current sampling circuit according to claim 2, wherein: The second temperature sampling circuit includes a resistor R10 and a negative temperature coefficient thermistor RT2. The other end of the shunt side is connected to pin 38 of the MCU chip U1 through the negative temperature coefficient thermistor RT2. The negative temperature coefficient thermistor RT2 collects the temperature of the shunt side. When the temperature is higher, the resistance of the negative temperature coefficient thermistor RT2 is smaller. A resistor R10 is provided between the shunt side and the negative temperature coefficient thermistor RT2, and the resistor R10 plays a voltage divider role.
5. The shunt current sampling circuit according to claim 1, characterized in that: A resistor R11 is provided between the negative temperature coefficient thermistor RT1 and the 37th pin of the MCU chip U1, and a resistor R12 is provided between the negative temperature coefficient thermistor RT2 and the 38th pin of the MCU chip U1 to play a current limiting role. Both the resistor R11 and the resistor R12 play a current limiting role.
6. The shunt current sampling circuit according to claim 1, characterized in that: The current sampling circuit includes a resistor R7, a resistor R8, a capacitor C11, and a capacitor C12. A resistor R7 is provided between pin 1 of the shunt SR1 and pin 31 of the MCU chip U1. A resistor R8 is provided between pin 2 of the shunt SR1 and pin 30 of the MCU chip U1. The resistors R7 and R8 play a role in protecting the MCU chip U1. A capacitor C11 and a capacitor C12 are provided between the resistors R7 and R8. One ends of the capacitors C11 and C12 are connected to the capacitors C11 and C12, and the other ends of the capacitors C11 and C12 are grounded. The capacitors C11 and C12 are common-mode capacitors, which play a role in filtering and eliminating common-mode interference.
7. The shunt current sampling circuit according to claim 6, characterized in that: A capacitor C13 is further disposed between the resistors R7 and R8. The capacitor C13 is a differential mode capacitor and plays a role in filtering and eliminating differential mode interference.
8. The shunt current sampling circuit according to claim 1, characterized in that: The CAN communication circuit includes a transceiver chip U2, an inductor L1, a resistor R4, a resistor R5, and a TVS diode group D2. Pin 5 of the MCU chip U1 is connected to pin 1 of the transceiver chip U2, pin 6 of the MCU chip U1 is connected to pin 4 of the transceiver chip U2, pins 7 and 6 of the transceiver chip U2 are both connected to the communication interface, and inductor L1, resistor R4, resistor R5, and TVS diode group D2 are arranged in sequence between pins 7 and 6 of the transceiver chip U2 and the communication interface. Resistors R4 and R5 are terminal resistors, and resistors R4 and R5 play a role in eliminating signal reflections in the communication cable. Capacitors C9 and C10 are common-mode capacitors, which play a role in filtering and eliminating common-mode interference, and TVS diode group D2 plays an anti-static role.
9. The shunt current sampling circuit according to claim 1, characterized in that: The MCU circuit is also connected to a crystal oscillator circuit, which consists of a capacitor C14, a capacitor C15, and a crystal oscillator Y1. The crystal oscillator circuit provides the MCU chip U1 with the required precise reference frequency or stable clock signal.
10. The shunt current sampling circuit according to claim 1, characterized in that: The program burning interface includes an interface J2, and pin 4 of the interface J2 is connected to pin 46 of the MCU chip U1; the communication interface includes an interface J1, and pin 4 of the interface J1 is connected to pin 7 of the transceiver chip U2, and pin 3 of the interface J1 is connected to pin 6 of the transceiver chip U2.