Railway Rolling Stock Power System

The Railway Power System provides Class S2 hold-up per EN 50155: 30ms at nominal input voltage, 10ms at minimum input voltage. This ensures continued operation during brief power interruptions from circuit breaker operations or battery switching. For applications requiring longer hold-up (Class S3 - 100ms), external hold-up capacitors can be added to the input. The hold-up time is verified during type testing and depends on load current and input voltage. For critical applications, we recommend calculating hold-up time for your specific operating conditions and adding margin.

For critical applications, verify hold-up time requirements and consider external capacitors if longer ride-through is needed.

The solution includes comprehensive protection for regenerative braking transients: Input TVS diodes clamp fast transients

Active clamp circuits handle sustained overvoltage

The RHKW converters withstand 1.5x nominal voltage for 100ms per EN 50155

Load dump protection handles voltage spikes up to 200V for 1 second. For severe environments with frequent or extreme transients, additional external surge protection is recommended. The protection circuits are designed to allow continuous operation through typical railway transients while protecting the converters from damage.

For applications with severe transients, consider adding external surge protection modules for enhanced reliability.

The solution includes EMI filtering recommendations for EN 50121-3-2 compliance: Common-mode choke (10-30mH) for conducted emissions

X-capacitors (0.1-0.47uF) for differential-mode noise

Y-capacitors for high-frequency common-mode noise

Proper earth grounding and shielding. The RHKW converters have internal filtering, but external components are typically needed to meet full Class B limits. P-Duke provides detailed application notes with recommended filter designs and PCB layout guidelines. Pre-compliance testing is recommended to verify meeting specific regional requirements.

Follow the EMI filter design in the application note and conduct pre-compliance testing to ensure EN 50121 compliance.

The RHKW converters are certified to EN 61373 Category 1, Class B for body-mounted equipment. For bogie-mounted applications with higher vibration levels (Category 1, Class A), additional mechanical mounting considerations may be required. The converters withstand 50g shock and 1.5g RMS random vibration, but bogie mounting typically sees higher levels. For bogie applications, we recommend: Using additional mechanical support or damping

Selecting components with higher vibration ratings if available

Conducting vibration testing on the complete assembly. Contact our FAE team for guidance on bogie-mounted applications.

For bogie-mounted equipment, consult our FAE team to verify vibration ratings and mounting recommendations.

For reliable long-term operation, we recommend designing for 60°C maximum ambient temperature: The converters are rated to 105°C with derating, but lower temperature extends life

MTBF doubles for every 10°C reduction below maximum

Natural convection is assumed - improve airflow if possible

Use thermal vias and copper pours on PCB to spread heat

Consider heatsink mounting for high-power or high-temperature applications. The thermal design should account for worst-case conditions including maximum load, minimum input voltage (highest current), and maximum ambient. Thermal modeling and testing are recommended for critical applications.

Design for 60°C maximum ambient with adequate airflow or heatsinking for 15+ year service life.

P-Duke provides comprehensive documentation for railway approval: EN 50155 test reports covering all requirements

EN 61373 shock and vibration test reports

EN 45545-2 fire safety test reports

EN 50121-3-2 EMC test reports

IEC 62368-1 safety test reports

MTBF analysis and reliability predictions

Material declarations and RoHS/REACH compliance. The documentation package includes type test certificates from accredited laboratories, factory production control documentation, and quality management system certificates. For specific projects, customer-specific test reports and witness testing can be arranged.

Request complete certification documentation early in your project to support the railway approval process.