Fault location and interference elimination of new energy bus CAN bus

Ankai bus fault diagnosis documentary

Ankai New Energy Bus is an early-stage R&D and mass-operated electric bus company in China. It was the first country to report on electric vehicles and the number of announcements was the first in the country. The current domestic market share reached over 70%, and it was exported to Europe and the United States in large quantities. The leading brand of the industry. The reason why Ankai wins the trust of a wide range of users lies in the company's high standards for driving safety and reliability. In response to the widespread problem of electromagnetic interference in CAN buses for new energy buses, Ankai and Guangzhou Zhiyuan Electronics Co., Ltd. used CANScope-Pro professional CAN bus analyzer to locate faults, eliminate interference, and conduct reliability tests. The new energy bus will run steadily.

● Spectrum analysis accurately locates the root cause of the fault

New energy buses are different from traditional passenger cars in that they use batteries and capacitors to store energy, and then drive the electric motor to drive the vehicle through reversed communication. When a passenger car accelerates or decelerates, a huge current change caused by the inverter generates a strong magnetic field disturbance and is coupled to a nearby CAN bus through a power cable, causing communication delays and interruptions. It may even result in equipment crash or damage. As a result, the instrument panel display is lagging. The failure of control has seriously affected people’s lives and property.

CANScope-Pro uses FFT spectrum analysis statistics to accurately locate the interference source frequency and the inverter frequency.



● Anti-jamming solution Based on the customer's rectification goal, three thorough solutions were proposed in the report of the Zhiyuan Electronic CANScope-Pro:

1. Customer's follow-up R & D products CAN bus interface are using CTM1051 isolation transceiver module, to achieve power and signal isolation limit, to prevent strong interference signals into the main circuit lead to controller crash;

2. Replace the current wire rods, use twisted pairs to shield the twisted pairs more closely, and improve the anti-interference ability of the cables;

3. For buses that have already been shipped, install a CANbridge isolation bridge to ensure safe operation of the vehicle.

Through rectification, the interference signal is greatly reduced. With the CANScope-Pro spectrum analysis, the requirements for safe operation can already be met.


● Reliability testing improves system robustness To further enhance the reliability of the CAN bus system of Ankai New Energy Bus, Zhiyuan Electronics has developed a comprehensive reliability test for Ankai using CANScope-Pro:

Position tolerance test: verify that the CAN node of the bus will crash if the baud rate fluctuates;

 Message stress test: verify whether the CAN node of the bus will crash in the case of large data load;

 erroneous baud rate pressure test: verify whether the bus CAN node will crash at the wrong baud rate;

 Anti-jamming capability test: verify whether the passenger car CAN node will crash in the case of high-intensity interference;

 Bus short-circuit test: verify that bus CAN node can be self-recovered in the event of a bus short circuit;

 Bus break test: verify that the CAN node of the bus can be self-recovered in the case of a bus break;

Geng Rong anti-increase stress test: verify that the passenger car CAN node can adapt to the maximum capacitive reactance;

 Bus network impedance test: verify that the passenger car CAN node can adapt to the highest impedance value;

 For positive and negative power supply or ground short circuit: Verify that the bus CAN node can be self-recovered when the bus is connected to the positive or negative power supply or ground short circuit.

Terminal resistance change pressure test, etc.: Verify that the bus CAN node can adapt to the range of terminating resistance.

 These reliability tests validate the compressive and self-recovery capabilities of CAN bus devices of passenger vehicles under these extreme conditions. Through the joint research of Zhiyuan Electronics and Ankai, the robustness of the CAN bus system of Ankai bus has been fully improved.

● Comprehensive and Efficient Localization Services As a leading company in the domestic CAN bus, Guangzhou Zhiyuan Electronics Co., Ltd. is equipped with highly skilled CAN bus technology engineers in major cities in China, and can provide timely services to customers and provide professional test reports. solution.

Zhiyuan Electronics is one of the earliest companies to enter the measurement instrument industry in China. It has nearly 400 senior research and development engineers and sales and service outlets throughout the country. It not only responds quickly to customer requirements, but also provides customized services based on the differentiated needs of industry users. We will unswervingly promote and lead the development and promotion of high-end equipment in China. I believe that because of our existence, the world will be different.

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