Power Conversion Supplies Drive Efficiency and Reliability in Modern Railways

Modern railway systems prioritize using existing power grids for train operations. This is achieved through electric power conductors like overhead lines (OHL) or third rails. Third rails run beside or between the tracks, while overhead lines are made up of wires that are hung above the tracks. Trains collect electricity from these conductors using pantographs (OHL) or contact shoes (for third rails). As the trains draw electricity from these sources, it powers onboard electric motors situated inside the train.

Power conversion is made to power the motors and DC/DC converters are integrated to run multiple loads present on a train while enhancing efficiency, dependability, and safety. In addition to providing regulated voltage, DC/DC converters can withstand extreme situations such as extreme heat, constant vibrations, and other environmental stresses specific to railway operations. 

In this article, we will be discussing the importance of DC/DC converters for railway systems, selection criteria for DC/DC converters, important features of these converters, and some of their applications in railways. We will also discuss the ability of MPD’s DC/DC converters to offer a diverse selection range tailored to the technical requirements of railway applications while ensuring high efficiency, wide input voltage ranges, suitable output power and robust protection features.

Different Types of Loads in Railway Systems Requiring DC/DC Converters

Trains and railway systems contain multiple kinds of loads, each of which performs a particular job within the system. These include 

  • Safety and signaling equipment such as emergency lighting systems, fire detection systems, and horns
  • Ticketing and information systems such as ticket vending machines, passenger information displays, and electronic signage
  • HVAC systems which include air conditioning compressors, HVAC fans, and temperature controllers
  • Communication equipment such as radios, Wi-Fi routers, and GSM modules
  • Onboard entertainment systems which include LCD screens, audio speakers, and multimedia players
  • Control and monitoring systems which include sensors, actuators, control panels, and data acquisition systems


These various loads might need different voltage ranges to operate. In order to power these loads, maintain consistent performance by controlling voltage levels, shield delicate electronic components from voltage fluctuations, and improve passenger safety, comfort, and operating efficiency—DC/DC converters are essential. 

Why DC/DC Converters for Trains?

Before talking about the reasons for employing any type of converter, it is essential to understand the different possible types of inputs to a railway system, because converters serve as a bridge between input and output. The type of train, electrification system, infrastructure in place, and protocols followed in a country can determine the type of input power.

Electric trains can get their input power in alternating current (AC) or direct current (DC) form from overhead wires or third rails respectively. Even for diesel-run locomotives, a generator may provide either DC or AC power depending on its design and the train’s electrical system. Sometimes, trains may use hybrid power systems that combine energy stored in batteries—which are normally charged with direct current (DC) power—with electricity from overhead wires or diesel engines. Furthermore, in certain trains, onboard power production may be supplemented by renewable energy sources like solar panels, which can provide DC power for uses.

All of these trains will entail various DC loads which are discussed above. So, to either change the form of input voltage or the level of this voltage, DC/DC converters will be used (although an inverter will also be added for the former). In addition to this, these converters are essential to the operation of the railway system in the following ways.

Voltage Regulation: DC/DC converters in trains make sure that the different systems operate at constant voltage levels. For instance, they control the voltage applied to lighting systems such that, even in the event of input voltage variations, the train’s brightness remains constant.

Compatibility with Various Power Sources: The power source for loads in a train might keep switching between batteries, diesel generators, overhead wires, and other available supply options. The purpose of DC/DC converters is to ensure that critical systems keep getting a continuous power supply. For example, air conditioning systems rely on consistent voltage levels regardless of the power source, ensuring passenger comfort throughout their journey. DC/DC converters designed by MicroPower Direct fulfill these criteria by providing smooth integration and switching between various sources in a railway system. 

Efficiency Optimization: Efficiency is essential in all electric systems to reduce energy losses and heat production during power conversion. The appropriate DC/DC converter ensures that fuel consumption and other operational costs are decreased by contemporary trains. 

Electromagnetic Interference Mitigation: To ensure uninterrupted operation of communication equipment, including radios, Wi-Fi routers, and GSM modules, provision of noise-free voltages is necessary. Trains run in high-EMI conditions, so the filtering of input signals is employed to mitigate electromagnetic interference. DC/DC converters with a built-in filter can serve this purpose effectively and contribute to the dependable functioning of onboard electronics.

Adaptation to Voltage Fluctuations: Regenerative braking and power supply variations may cause voltage fluctuations in trains. By adjusting to these variations, DC/DC converters keep the output voltage steady and shield delicate electronics from being affected.

Choosing the Right DC/DC Power Converter for your Railway System

Prior to choosing DC/DC converters for any railway application, it is important to understand the wide variety of equipment installed in the specific rail system and knowing if their specifications are adapted to certain operating conditions and environmental factors. After this step, converters can be selected for each equipment separately. Important selection parameters include voltage compatibility, power rating, vibration tolerance, and temperature tolerance. The increasing variety of onboard equipment has led to a greater need for a wide range of DC/DC converters.

Input Voltage Range

An important consideration when choosing the right DC/DC converter for railway applications is the input voltage range. Variations in power sources or operating circumstances (like the varying length of a distribution line as a train moves) often result in changing input voltages for railway systems. A broad input voltage range is more likely to guarantee compatibility and dependability, enabling the converter to function flawlessly in the ever-changing railway setting. Such adaptability is provided by MicroPower Direct’s DC/DC converters; examples of such modules include the MR1011S and MR08XXRUI series. For instance, the MR1011S offers an input voltage range of 40VDC to 160VDC. Similarly, the MR08XXRUI has products with an input voltage range of 13-70VDC (24V being nominal voltage) and 42-176VDC (110V being nominal voltage) which are wide ranges able to guarantee a steady and constant output voltage independent of input variations.

Input Voltage Range of MicroPower Direct DC/DC Converters

Wide Operating Temperature Range

Electronic components are often exposed to severe temperature changes in railway settings, making converters with a broad thermal tolerance range essential for dependability. Modules such as the MR0611S, MR08XXRUI, and MR2011S series are examples of MicroPower Direct’s DC/DC converters, which provide reliable operation at different temperatures. The MR0611S, for example, functions reliably at temperatures ranging from -40°C to +85°C (equivalent to OT6 level) and the MR75SRW can work well between -40°C and +61°C guaranteeing steady performance in harsh circumstances. This corresponds, mathematically, to a range in which the converter may continue to operate efficiently, assisting in the continuous operation of vital railway systems.

Operating Temperature Range for MicroPower Direct DC/DC Converters

Output Accuracy

Many devices, installed in railway systems, need a stable supply falling very close to their nominal readings continuously. This requirement necessitates the usage of DC/DC converters which stay accurate even with changing conditions so that onboard equipment can keep functioning according to requirements. Output precision is a feature of MicroPower Direct’s DC/DC converters, such as the MR1011S and MR1511SRU series. The MR1011S, for example, guarantees constant and dependable voltage control with an output accuracy of ±1.0% (whereas its load regulation stands at ±0.5% and line regulation at ±0.2%). Similarly, the output accuracy of the MR1511SRU is ±1.0% (whereas its load regulation stands at ±0.5% and line regulation at ±0.2%). This degree of precision reduces the possibility of voltage variations, component malfunctioning, and system breakdowns. MPD’s DC/DC converters with high output precision are the recommended option for railway applications because they can maintain safety and effectiveness of onboard equipment in circumstances where a reliable power supply is critical. 

Output Power

An important factor to consider when assessing DC/DC converters for railway applications is their output power or power rating (ref. law of conservation of energy). Many gadgets and subsystems are used in a railway system and each of these could be powered by a separate DC/DC converter. Or the ones having the same voltage requirements could use one converter altogether. The output power rating of each supply module should be compatible with the power requirements of the corresponding subsystem or device. MPD has designed a variety of DC/DC converters for railway applications with varying power ratings including the MR0611S, MR08XXRUI, and MR4011SRU series. The MR0611S, for example, has an output power of 6W, which is sufficient for different railway applications. Comparably, the 8W output power of the MR08XXRUI series satisfies the energy needs of the onboard electronics. Modules with 50W (MR50SRW) and 75W (MR75SRW) power ratings are also available for bigger loads. MPD DC/DC converters with enough output power capacities guarantee that key systems continue to function with optimal efficiency.

Reinforced Insulation

Reinforced insulation is crucial to prevent electrical problems and guarantee the safety of passengers and operators in train settings, where electrical systems are susceptible to possible voltage surges, fluctuations, and vibrations. Reinforced insulation enhances both mechanical and electrical properties. For railway applications, MPD’s converters with strengthened isolation are the best option as they guarantee the reliability as well as security of onboard electronics in harsh conditions. The converters of the MR4011SRU series by MPD, for instance, can tolerate voltage differentials of up to 3000 volts. In other words, these converters provide 3kV reinforced isolation.

Reinforced Insulation Voltage for MicroPower Direct DC/DC Converters

Sturdy Design

For home applications, electronic boards are fixed in a place and rarely move. In contrast, on trains, onboard electronic components keep vibrating and undergo mechanical stress. As such, the system designer must consider that such DC/DC converters are selected which will maintain their integrity and performance even in such conditions. MPD has ensured that it provides a range of DC/DC converters which have sturdy designs. MPD railway power supplies have double-sided SMD with terminals through hole reflow soldering and reliable structure. Tolerance towards vibrations is also higher for MPD converters meeting IEC/EN/ 61373-1 class B standard. In contrast, some non-MicroPower Direct DC/DC converters have been designed with double-story building patch terminal and weak welding points.

Real World Applications

Train Running Condition Monitoring

Trains need equipment to evaluate the state and functionality of the train and its parts. Train operating condition monitoring requires the real-time monitoring of several characteristics including speed, temperature, vibration, and power consumption. For the purpose of data collection and transmission for analysis and decision-making, these monitoring systems depend on sensors, data collecting systems, and communication units. Different MPD DC/DC converters serve as the power supply backbone for these system components, providing stable and regulated power to the systems as shown in the block diagram below.

Block Diagram for Train Running Condition Monitoring System

High-speed Rail VIP Seat Application

On high-speed trains, MicroPower Direct’s DC/DC converters are essential for guaranteeing the convenience, safety, and comfort of passengers sitting in the train. High-speed train seats come with a variety of features and facilities to provide passengers with a first-rate travel experience. Manual adjustment switches, tilt and slide sensors, switch indications, and electrical device charging connections are a few examples of these conveniences. The power supply of electronic parts and systems installed in seats can be regulated by MPD DC/DC converters. The converter chosen for this purpose should be able to provide high transient power without being affected in a strong electrostatic environment. It must also be equipped with high insulation and tolerate vibrations without compromising its functionality.

Block Diagram for Train Running Condition Monitoring System

Gate Control System Applications

Gate control systems are used in a variety of situations, including parking lots, railroad crossings, toll booths, and security checkpoints. Typically, gate control systems include electromechanical components such as CPU systems, transceivers, motors, motor driving chips, and electronic control units. For these control units to work properly, they need steady, regulated power, which is where MPD DC/DC converters come into play.

Block Diagram for Gate Control System application

Conclusion: Revolutionizing Railway Infrastructure

In conclusion, MicroPower Direct’s DC/DC converters are essential to the safe and reliable functioning of railroads and related applications. These converters are vital components that provide different onboard systems and equipment in railroad environments the necessary power regulation, voltage control, and isolation capabilities. It is impossible to underestimate the significance of DC/DC converters in railway applications since they have a major impact on the effectiveness, performance, and security of onboard systems. MPD converters address the particular challenges presented by railway environments by offering stable voltage levels, accommodating multiple power sources, optimizing energy efficiency, mitigating electromagnetic interference, adapting to voltage fluctuations, optimizing space utilization, and guaranteeing resilience to extreme temperatures. The industry recognizes MPD DC/DC converters for their wide range of options that are specifically designed to meet the technical demands of railway applications. 

Railway engineers may improve the durability and performance of onboard systems with the dependability and flexibility that MPD converters provide, thanks to their broad input voltage range, strong protective features, industry standards compliance, and high efficiency. Additionally, MPD converters are essential to the smooth functioning of vital railway applications like gate control systems, high-speed rail VIP seat systems, and train operating status monitoring. MPD converters serve as the backbone of the power supply in these real-world applications, supporting the proper operation of critical railway infrastructure by powering sensors, data gathering systems, communication units, electromechanical components, and electronic control units.

For more information about MicroPower Direct’s DC/DC converters and how they can meet the specific requirements of your railway applications, please contact the MPD team. Our team of professionals is prepared to help you choose the best converters for your railway system and to provide all-encompassing assistance to make sure your projects are successful.