This paper explores the power supply requirements and classification of rail transit vehicle equipment, focusing on the EN50155-2007 standard for in-vehicle electronic devices. It outlines the key considerations for selecting DC/DC converters, including isolation, input voltage range, operating temperature limits, and other essential characteristics. Based on these factors, a practical guide is provided to assist in the selection of isolated DC/DC power modules for in-vehicle electronic systems.
China has become a global leader in high-speed rail, with more than half of the world's high-speed rail operations. During the 13th Five-Year Plan (2016–2020), China aimed to expand its railway network to 150,000 kilometers by 2020, with 30,000 kilometers dedicated to high-speed lines. This represents an increase of 29,000 kilometers in total rail infrastructure, and 11,000 kilometers in high-speed rail. The investment in high-speed rail during this period was expected to exceed 4 trillion yuan, while locomotive development received around 800 billion yuan.
Internationally, China’s high-speed rail projects have made significant progress. Construction has begun on the Yawan High-Speed Railway in Indonesia and the Zhonglao Railway. The Serbian section of the Sino-Thai Railway and parts of the Hungarian line are also under development. Additionally, the Moscow-Kazan High-Speed Rail project in Russia has been officially confirmed. These developments highlight how Chinese railways have become a symbol of “Made in China†and are central to the government’s “Going Out†strategy under the Belt and Road Initiative. In developing countries like India, there is great potential for future railway expansion.
With the continuous advancement of the railway industry, improving operational reliability and passenger comfort has led to the widespread use of electronic devices in rail transportation. The power supply for in-vehicle electronics is typically provided by the vehicle's auxiliary power system, which includes the battery and charger. Under normal conditions, the charger supplies low-voltage bus power, while the battery supports critical systems such as the Train Control and Management System (TCMS) and lighting. In case of a charger failure, the battery acts as a buffer to maintain basic functions.
The vehicle electronics system consists of components such as the TCMS, signaling system, passenger information system, and air conditioning control. To ensure reliable operation and prevent fault propagation, each subsystem requires isolated power to protect against electrical failures. These systems are interconnected via a train communication bus, allowing the driver to monitor and control various functions remotely through the onboard controller. As intelligent technologies continue to evolve, the demand for isolated power solutions increases.
In-vehicle electronic devices must meet strict standards such as EN50155, which covers environmental, electrical, and electromagnetic compatibility (EMC) requirements. Key criteria include:
1. Environmental conditions: altitude, temperature, humidity, shock, vibration, and IP rating.
2. Electrical specifications: power requirements, isolation, and voltage tolerance.
3. Surge and electrostatic discharge resistance: the ability to withstand overvoltage up to 1.4 times the nominal voltage.
4. EMC compliance: meeting CE, RE, RS, CS, Surge, EFT, and ESD standards depending on the interface.
5. Reliability and service life: devices must operate for at least 100,000 kilometers or one year without failure.
6. Additional requirements: handling power interruptions, voltage drops, and short-circuit protection.
When selecting power supplies for in-vehicle electronics, several factors must be considered:
- **Shock and Vibration**: Railway environments subject equipment to harsh vibrations. Potting techniques can enhance the mechanical resilience of power modules. For example, Jinshengyang’s R3 series meets vibration tests of 10–55Hz at 10g for 30 minutes along XYZ axes.
- **Voltage Range**: Vehicle batteries typically operate at 24V, 48V, 72V, 96V, and 110V. Power supplies must support input ranges from 0.6VN to 1.4VN. Jinshengyang’s URB1D24YMD-6WR3 operates within 40–160VDC, supporting multiple battery levels.
- **Isolation Requirements**: Dielectric strength depends on the battery voltage. A 1500VAC isolation is recommended to handle transient overvoltages. Jinshengyang’s 6WR3 module meets 1500VAC/2250VDC isolation.
- **Temperature and Humidity**: Power supplies must function between -40°C and 85°C. Jinshengyang products pass rigorous thermal cycling and humidity tests.
- **Special Surge Protection**: Standards like RIA12 require devices to withstand surges up to 3.5 times the input voltage. Jinshengyang’s FC-CX3D uses an active clamp circuit to limit surge voltages effectively.
- **Power Interruption Handling**: Capacitors may be added to meet 10ms interruption requirements.
In conclusion, this paper provides a comprehensive analysis of in-vehicle electronic equipment requirements and offers guidance for selecting appropriate isolated DC/DC power modules. This knowledge is crucial for ensuring the safe and reliable operation of rail vehicle power systems.
OLED is organic light-emitting diode (D1de), which has the characteristics of self illumination, high brightness, wide viewing angle, high contrast, flexibility, low energy consumption and so on. Therefore, it has been widely concerned. As a new generation of display mode, it has gradually replaced the traditional liquid crystal display, and is widely used in mobile phone screen, computer display, full-color TV and so on. OLED display technology is different from traditional liquid crystal display technology. It does not need backlight. It uses very thin organic material coating and glass substrate. When there is current passing through, these organic materials will emit light. However, as organic materials are easy to react with water vapor or oxygen, OLED displays have high requirements for packaging.
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