Datasheet download　

Product features:

◆ Ultra-wide input voltage range (4:1)

◆ Efficiency as high as 87%

◆ Isolation voltage: 3000VDC

◆ Input under-voltage protection, output short-circuit, over-current, over-voltage protection

◆ Operating temperature range: -40℃ to +85℃

◆ Z guide rail product models have reverse connection protection function

◆ International standard pin method

◆ Three-year warranty period

　　DCDC power modules for railway applications: Highly reliable solutions and troubleshooting guide

　　summary: Railway power modules are the core for the stable operation of trains, signaling systems, and on-board electronic equipment. This article provides an in-depth analysis of the key technical requirements of railway-specific DCDC power modules, such as the EN 50155 standard, answers common questions, and provides detailed troubleshooting guides to help system integrators and engineers ensure the highest reliability of rail transit systems.

　　1. The particularity and core requirements of railway power supply

Unlike ordinary industrial power supplies, railway power supplies operate in extremely harsh environments and must meet a series of stringent standards, the most core of which areEN 50155. This standard defines the specifications that railway on-board electronic equipment must comply with, mainly in the following aspects:

　　Wide input voltage range: Must deal with severe input voltage fluctuations stably. For example, a nominal 24V system needs to cover an input range of 14V to 36V; a nominal 72V or 110V system needs to cover a wider range of voltage transients and surges.

　　Strict EMC and insulation performance: It must pass standards such as EN 50121-3-2 and have extremely strong anti-electromagnetic interference capabilities. At the same time, the noise it generates must be minimal to avoid affecting other sensitive equipment. Reinforced insulation (usually requiring >3.5kV AC) is a basic requirement for safety.

　　Extremely high mechanical and environmental reliability: Must withstand the test of extreme conditions such as vibration, shock, moisture, salt spray, high and low temperatures (usually the operating temperature range is -40°C to +85°C).

　　Complete protection functions: Built-in input reverse connection protection, overvoltage protection, undervoltage protection, overload protection and short circuit protection ensure the safety of the power supply itself and back-end equipment in case of fault.

　　2. Frequently Asked Questions (FAQ) about Railway DCDC power supply

　　Q1: Why must railway power supplies comply with EN 50155 standards?

A: EN 50155 is an internationally recognized quality standard for railway applications. It ensures that electronic equipment can continue to work safely and reliably in complex and dangerous railway environments. Complying with this standard is a mandatory passport for products to enter the global railway market, and is also a fundamental guarantee of system reliability.

　　Q2: Our equipment is on the locomotive, and there are often high-voltage pulses at the input end of the power module. How to deal with it?

A: This is a typical "surge" or "overvoltage pulse" phenomenon, originating from the traction system, circuit breaker opening and closing, etc. Qualified railway DCDC power supplies have integrated basic surge suppression circuits. But for extreme cases, we RECOMmend adding additionalTVS tube (transient suppression diode)orVaristor, build multi-level protection to clamp the input peak voltage within the safe working area of ​​the module.

　　Q3: Why is it difficult for the power module to start up in a low temperature environment?

A: Low temperature will cause the equivalent series resistance (ESR) of the electrolytic capacitor to increase sharply and the internal resistance of the battery to increase, causing a sudden voltage drop during startup and triggering undervoltage protection. Professional railway power supplies will useWide temperature ceramic capacitoror specially designed electrolytic capacitors withsoft startorCapacitive load starts step by stepfunction to solve low-temperature starting problems. When selecting, it is important to pay attention to the module's specified operating temperature range.

　　Q4: How to ensure that the power module does not fail in a strong vibration environment?

A: First of all, the choice was passedEN 61373 (Vibration and shock testing of railway equipment)Standard certified power supply products. Secondly, in terms of installation, in addition to using the screw holes that come with the module to fix it, for modules with higher power, it is recommended to add aMechanical reinforcement striporThermal glue fixation, to disperse stress and prevent solder joints from fatigue fracture due to long-term vibration.

　　3. Railway DCDC power supply troubleshooting guide

When a power-related failure occurs in the system, please follow the logic from simple to complex to troubleshoot.

Possible causes of troubleshooting steps and solutions

　　No output, indicator light does not light up1. The input power is not connected

2. The input fuse is blown

3. The input cable has poor contact or reverse connection.

4. Internal module failure 1. Check whether the front-end power supply is normal and measure the input port voltage.

2. Check whether the fuse is intact. If it is blown, check the rear short circuit point.

3. Confirm that the input polarity is correct and the terminals are tightly crimped.

4. If the first three points are normal, the module may be damaged and needs to be replaced.

　　Output is unstable and the system restarts frequently1. Input voltage fluctuation is out of range

2. Output overload or short circuit

3. Poor heat dissipation leads to over-temperature protection

4. EMC interference 1. Monitor the input voltage waveform to confirm whether there is an instant drop or excessive surge.

2. Disconnect the load, measure whether the no-load output is normal, and gradually check the load circuit.

3. Check whether the module installation surface is flat, whether thermal grease is applied, and whether the environment is well ventilated.

4. Check the shielding and grounding of the input/output cables to ensure compliance with EMC design specifications.

　　The module is abnormally hot1. Overload operation

2. Improper setting of switching frequency

3. The heat dissipation path is blocked

4. Reduced efficiency (such as component aging) 1. Measure the actual load current to confirm that it does not exceed the module rating.

2. (If adjustable) Appropriately reducing the switching frequency can reduce switching losses, but may increase ripple.

3. Clean the dust on the radiator and ensure it is in close contact with the bottom surface of the module.

4. The efficiency may decrease slightly after long-term use, so sufficient design margin needs to be left.

　　Output voltage accuracy has large deviation1. Insufficient remote sampling compensation

2. The line voltage drop is too large

3. The load regulation rate is out of tolerance 1. If remote sampling is used, ensure that the sampling point is directly located at the load end to compensate for the line voltage drop.

2. Thicken the output cable to reduce transmission loss.

3. Measure under no-load and full load conditions and compare with the load regulation index in the data sheet.

　　EMC test failed1. Insufficient input/output filtering

2. Improper layout and grounding

3. Imperfect shielding 1. Add or optimize π-type filters at the input/output ends.

2. Ensure that the filter capacitor is as close to the module pin as possible, the power loop area is minimized, and the grounding impedance is low.

3. Check the chassis shielding integrity and ensure that all interfaces use shielded cables and are 360° grounded.

　　4. Best practices in selection and design

To ensure nothing goes wrong, please follow the following suggestions during the selection and design stages of railway power supply projects:

　　Leave sufficient design margin: In power selection, it is recommended to use the power derating curve. At the highest ambient temperature, the actual power used does not exceed 70%-80% of the rated power.

　　Pay attention to input filtering: Even if there is a filter circuit inside the module, it is still a good practice to design a front-stage EMI filter at the system level, which can significantly improve the EMC performance of the entire machine.

　　Thermal management is a priority: Heat is the primary killer of electronic products. Plan an efficient heat dissipation path in the early stage of structural design, and give priority to heat dissipation through the chassis.

　　Choose a trusted partner: The railway industry is related to life safety, be sure to choose to ownIRIS (International Railway Industry Standard) certification, a power supply supplier whose products have been proven by the market for a long time.

　　in conclusion

Railway-specific DCDC power supply is the cornerstone to ensure the safety and on-time operation of the rail transit system. Its high reliability stems from strict compliance with international standards and deep adaptation to extreme environments. By understanding its technical core, anticipating common problems, and mastering scientific troubleshooting methods, you will be able to build a stronger and more stable vehicle power system. If you need DCDC power supply product selection manual or technical support that complies with EN 50155 standards, please feel free to contact us.