HOT Search
Hot News
Product recommendation
With the rapid development of the new energy vehicle, energy storage power station and various power engineering machinery markets, battery components are continuously upgrading and iterating towards higher voltage , larger capacity and higher power .
At present, the voltage of mainstream power battery packs in the market has reached 400V and 800V, while the voltage of energy storage power stations can reach 1500V or even higher levels. Under this trend, the safety management and control of high-voltage circuits has become much more difficult, and the electrical protection requirements of batteries and supporting equipment are also constantly increasing. Therefore, designing a battery management system (BMS) that is more suitable for high-voltage platform applications has become crucial.
Among them, digital isolators, as devices that can transmit digital signals between two different voltage domains, while blocking DC current paths and possessing excellent common-mode transient interference capabilities, can effectively assist battery management systems (BMS) in real-time monitoring of cell status parameters for comprehensive evaluation, and in realizing effective control of battery clusters according to preset logic, thereby ensuring the stable operation of the entire battery assembly.
At the same time, digital isolators can also interact with external devices through various interfaces such as I2C, CAN, and RS-485 to complete the coordinated control of various systems, ensuring that the cells can safely, reliably, and efficiently complete the power supply work.
As shown in the figure below, in the electrical isolation scheme of the battery management system (BMS), the Battery Monitoring (MCU) is the core control unit of the system. It needs to acquire key operating parameters such as voltage, current and temperature of the battery cluster in real time and communicate with the external control system.
Schematic diagram of electrical isolation scheme in Battery Management System (BMS)
However, functional modules such as the current sampling unit, cell monitoring unit (CSU), and CAN communication interface are often distributed in different potential domains. Some circuits are even directly connected to the high-voltage battery circuit, with a potential difference of hundreds or even thousands of volts between them and the low-voltage control domain where the MCU is located.
If signal transmission is carried out directly, it will not only easily cause problems such as ground loops and electromagnetic interference, but may also lead to high-voltage faults being transmitted to the control system.
The above pain points can be effectively solved by using digital isolators, thus building a signal transmission link for BMS that balances security and reliability.
In the current detection stage, the digital isolator can safely transmit the current data obtained by the high-voltage side sampling circuit to the main control MCU, realizing high-precision current monitoring and status analysis.
In the cell monitoring and equalization control stage, digital isolators can isolate the potential difference between different battery clusters, ensuring the accurate transmission of voltage sampling, temperature detection and equalization control commands.
In communication interfaces such as CAN and RS-485, digital isolators can effectively suppress common-mode noise and ground loop interference, thereby improving the communication stability of the system.
In addition, when the BMS performs fault diagnosis tasks, the digital isolator can effectively prevent the fault from spreading to other circuits during the fault handling process, while ensuring that the diagnostic signal can be accurately transmitted to the main control MCU so as to quickly locate and resolve the fault.
In essence, a digital isolator not only performs signal isolation and data transmission functions, but also serves as a crucial bridge connecting high-voltage power systems and low-voltage control systems.
A digital isolator enables secure communication between high and low voltage domains, allowing the BMS to continuously and accurately sense the cell status and promptly identify abnormal conditions such as overvoltage, undervoltage, overcurrent, and overtemperature.
This, in turn, prompts the main control MCU to quickly execute protection strategies, providing safer, more efficient, and more reliable energy management for new energy vehicles, energy storage power stations, and industrial power equipment.
For example, the CMT812X, CMT804X, and CMT826X are a series of standard digital isolators with different numbers of channels and directional configurations. They can be used with common serial communication interfaces such as I2C, SPI, and RS-458 to form a highly efficient electrical isolation barrier, blocking the impact of surges and electromagnetic noise in high-voltage systems on low-voltage logic circuits, and ensuring that digital signals can be transmitted accurately, efficiently, safely, and reliably to the receiving end. They are especially suitable for BMS systems with both high and low voltage circuits.
The CMT10XX and CMT8308X are a series of isolated interface chips that integrate RS-485 and CAN interfaces. They achieve a high degree of integration of digital isolation and physical layer interface functions within a single chip, enabling the direct construction of isolated communication links. This effectively suppresses the impact of common-mode interference and ground potential difference on bus signals, and prevents abnormal voltage on the high-voltage side from being conducted to control and peripheral ports through the communication lines.
In complex electromagnetic environments , these isolation interface chips can still ensure the integrity and timing consistency of differential signals, ensuring stable data communication between internal modules and between the BMS and external devices such as controllers and chargers. They are particularly suitable for BMS application scenarios with high requirements for communication robustness and system security.
https://www.hoperf.com/service/apply/
If you are interested in HOPERF's independently developed series of digital isolators (general-purpose isolators, isolation interfaces, isolation drivers, isolation ADCs/op-amps), please scan the QR code above or copy and open the link at the end of the article to apply for samples. We will be happy to serve you!