An isolated communication circuit based on CAN communication
By introducing components such as level matching modules and optocoupler isolators into the battery system, the communication instability caused by signal crosstalk and EMC radiation between devices is solved, and independent isolation and efficient communication between devices are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 杭州衡驰科技有限公司
- Filing Date
- 2025-07-22
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies in battery systems suffer from problems such as low-voltage signal crosstalk and EMC electromagnetic radiation between devices, leading to unstable communication, especially when communicating between devices from different manufacturers. Furthermore, existing testing methods are inefficient, costly, and difficult to achieve effective isolation of high-voltage systems.
It employs a level matching module, a high-voltage DC/DC module, a level conversion module, an isolation power supply module, a CAN communication converter, and an isolation IC. Signal isolation is achieved through an optocoupler isolator, resulting in a simple control strategy, reduced interference signal crosstalk, and improved communication stability.
It achieves independent communication isolation between devices, reduces system instability, simplifies control strategies, reduces system costs, and improves communication quality and reliability.
Smart Images
Figure CN224305758U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of communication isolation technology, and in particular relates to an isolated communication circuit based on CAN communication. Background Technology
[0002] With the development of the new energy industry, battery systems have been more widely used in automobiles and energy storage. As battery capacity continues to increase, the systems are becoming increasingly large, involving multiple series and parallel connections, photovoltaic systems, PCS systems, EMS systems, BMS systems, and other devices. This makes the entire energy storage system increasingly complex. Low-voltage signal crosstalk between each device, isolation between high-voltage communications, and EMC electromagnetic radiation can all affect system stability and generate unpredictable risks. This is especially true when using devices from different manufacturers with different signals, or when there is a lack of understanding of the device's communication ports, which can easily lead to unreliable communication. In order to effectively improve communication quality and enhance the controllability of the devices, a direct isolation communication module is needed to improve communication quality.
[0003] See existing technology Figure 1 Existing technical solutions offer simple measurement methods that are easy to implement, but suffer from very low testing efficiency, high cost, and lack of control, making them difficult to implement in high-voltage systems. The system architecture, involving multiple connected devices, connects the communication interfaces of device 1 (BMS10), device 2 (PCS20), and device 3 (EMS30). After a communication handshake signal is completed, data exchange occurs. Each device contains a DC / DC power module, a communication converter, an MCU, and related peripheral circuits. Device 2 (PCS20) has a high-power circuit on its inverter port that is directly connected to the power grid or high-power equipment. When the system performs high-current charging and discharging, EMC electromagnetic signals will directly interfere with the auxiliary equipment through the communication signal, leading to incomplete communication signals or data packet loss. When control devices from different manufacturers are configured at the communication end, the bus signal becomes extremely complex and prone to communication interruptions, especially when the isolation of other external device communication signals is unknown, easily causing communication instability. Therefore, there is an urgent need to add an intermediate communication relay that can achieve complete communication signal isolation without affecting signal quality. Utility Model Content
[0004] To solve the above problems, this utility model includes a level matching module, a high-voltage DC / DC module, a level conversion module, an isolated power supply module, two CAN communication converters, an MCU, and an isolation IC, wherein...
[0005] The output of the high-voltage DC / DC module is connected to a level matching module and a level conversion module;
[0006] The output of the level conversion module is connected to the isolated power supply module, the first CAN communication converter, the MCU, and the isolation IC.
[0007] The input of the isolation IC is connected to the MCU, and the output is connected to the second CAN communication converter;
[0008] The input of the first CAN communication converter is connected to the first device, and the output of the first CAN communication converter is connected to the MCU; the input of the second CAN communication converter is connected to the isolation IC, and the output of the second CAN communication converter is connected to one or more other devices.
[0009] Preferably, the isolation IC isolates the communication signal output by the MCU, and then performs level conversion through a second CAN communication converter to output a differential communication signal for direct communication connection with one or more other devices.
[0010] Preferably, the other one or more devices are capable of powering the entire isolated communication circuit via a level matching module.
[0011] Preferably, the high-voltage DC / DC module provides power output and supplies power to the first device through a level matching module.
[0012] Preferably, it also includes an optocoupler isolator, the input of which is connected to one or more other devices, and the output of which is connected to the first device. The other one or more devices output a high or low level signal, and the level signal output by the optocoupler isolator switches, waking up the first device and starting communication with the other one or more devices.
[0013] Compared with the prior art, the present invention has at least the following beneficial effects:
[0014] 1. Independent communication isolation module, eliminating the need to consider communication isolation issues between the two ends of the device;
[0015] 2. Simple to use, low system cost;
[0016] 3. The control strategy is simple. Communication handshake is performed through an optocoupler isolator, and communication protocol conversion is completed through the core controller MCU to achieve interoperability with external communication protocols.
[0017] A UG1 communication isolation module is added between the communication port of device 2-PCS, the communication port of device 1-BMS, and the communication port of device 3-EMS. When the EMC interference signal generated by device 2-PCS during high-current charging and discharging is output to the outside via the CAN communication line, the UG1 module can isolate the signal, effectively reducing system instability caused by crosstalk of interference signals generated by the device to the communication ports of adjacent devices. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of communication interfaces for various devices in the prior art;
[0019] Figure 2 This is a schematic diagram of the topology of an isolated communication circuit based on CAN communication according to a specific embodiment of this utility model;
[0020] Figure 3 This is a schematic diagram of the internal topology of an isolated communication circuit based on CAN communication, according to a specific embodiment of this utility model. Detailed Implementation
[0021] The technical solution provided by this utility model will be further described below with reference to the accompanying drawings.
[0022] See Figures 2-3 The isolated communication circuit UG1 of this utility model includes a level matching module UP8, a high-voltage DC / DC module UP7, a level conversion module (DC / DC) UP6, an isolated power supply module UP9, two CAN communication converters UA5 and UA8, an MCU-UC5, and an isolation IC-UI2, wherein...
[0023] The output of the high-voltage DC / DC module UP7 is connected to the level matching module UP8 and the level conversion module UP6; the output of the level conversion module UP6 is connected to the isolated power supply module UP9, the first CAN communication converter UA5, the MCU-UC5, and the isolation IC-UI2; the input of the isolation IC-UI2 is connected to the MCU-UC5, and the output is connected to the second CAN communication converter UA8; the input of the first CAN communication converter UA5 is connected to the first device (Device 1-BMS terminal 10), and the output of the first CAN communication converter UA5 is connected to the MCU-UC5; the input of the second CAN communication converter UA8 is connected to the isolation IC-UI2, and the output of the second CAN communication converter UA8 is connected to one or more other devices (Device 2-PCS terminal 20).
[0024] The isolation IC-UI2 isolates the communication signal output from the MCU-UC5, and then performs level conversion through the second CAN communication converter UA8 to output a differential communication signal for direct communication connection with one or more other devices. These other devices (device 2-PCS terminal 20) can power the entire isolated communication circuit UG1 through the level matching module UP8.
[0025] The high-voltage DC / DC module UP7 of this invention provides power output. One path supplies power to the BMS terminal 10 of device 1 through the level matching module UP8, and another path supplies power to the UC5 module, the first CAN communication module UA5, the isolation power supply module UP9, and the isolation IC module UI2 through the level conversion module UP6. The UI2 isolation IC module isolates the communication signal output by the MCU. Then, the CAN module of the second CAN communication module UA8 performs level conversion and outputs differential communication signals, which can directly communicate with the external device 2-PCS terminal 20 or the device 3-EMS terminal 20. The device 2-PCS terminal 20 can supply power to the isolation communication module. This invention can effectively reduce system instability caused by crosstalk between communication interference signals.
[0026] It also includes an optocoupler, whose input is connected to one or more other devices, and whose output is connected to the first device. When one or more other devices output a high or low level signal, the level signal output by the optocoupler switches, waking up the first device and initiating communication with the other one or more devices.
[0027] In a specific embodiment, the input end of the optocoupler is connected to device 2-PCS terminal 20, and the output end of the optocoupler is connected to device 1-BMS terminal 10. After the connection is completed and the device is powered on, the GPIO port of device 2-PCS terminal 20 will output an ISO_EN high and low level signal. After the Enable port of device 1-BMS terminal 10 detects the level jump signal, it wakes up the MCU. The system completes self-test and then sends out the BMS_CAN signal. Through the isolation communication module, it interacts with the PCS_CAN of device 2-PCS terminal 20 to complete the communication handshake function.
[0028] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.
[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An isolated communication circuit based on CAN communication, characterized in that, It includes a level matching module, a high-voltage DC / DC module, a level conversion module, an isolated power supply module, two CAN communication converters, an MCU, and an isolation IC. The output of the high-voltage DC / DC module is connected to a level matching module and a level conversion module; The output of the level conversion module is connected to the isolated power supply module, the first CAN communication converter, the MCU, and the isolation IC. The input of the isolation IC is connected to the MCU, and the output is connected to the second CAN communication converter; The input of the first CAN communication converter is connected to the first device, and the output of the first CAN communication converter is connected to the MCU; the input of the second CAN communication converter is connected to the isolation IC, and the output of the second CAN communication converter is connected to one or more other devices.
2. The isolated communication circuit based on CAN communication according to claim 1, characterized in that, The isolation IC isolates the communication signal output by the MCU, and then performs level conversion through a second CAN communication converter to output differential communication signals for direct communication connection with one or more other devices.
3. The isolated communication circuit based on CAN communication according to claim 1, characterized in that, The other one or more devices can power the entire isolated communication circuit via a level matching module.
4. The isolated communication circuit based on CAN communication according to claim 1, characterized in that, The high-voltage DC / DC module provides power output and supplies power to the first device through the level matching module.
5. The isolated communication circuit based on CAN communication according to claim 1, characterized in that, It also includes an optocoupler, whose input is connected to one or more other devices, and whose output is connected to the first device. When one or more other devices output a high or low level signal, the level signal output by the optocoupler switches, waking up the first device and initiating communication with the other one or more devices.