XP Power

Providing an approved, single DC-DC power solution which covers all nominal traction voltages from 24VDC through to 110VDC and complies with the latest electromagnetic compatibility and fire protection standards, simplifies system integration across all power platforms that may be encountered in rail applications, negating the need for multiple variants of electronic transportation equipment.

With decades of experience providing power solutions for the rail industry and its demands on equipment to withstand the harsh climatic, mechanical and electrical environments encountered on traction vehicles and rolling stock thousands of XP Power products have been installed on rolling stock and trackside equipment globally.

Applications ranging from lighting, information & entertainment, safety and engine management systems to signalling, crossing control, in cabin radio and displays all require DC-DC power conversion and must perform safely and reliably.

The two main standards, detailing the input supply requirements for electronic equipment in rail applications, are EN50155:2017 and EN50121-2-1:2016. The table below outlines the continuous input voltage ranges along with the brown out and transient requirements of the nominal DC input supplies detailed in EN50155:2017. The same standard details the interruptions, surges, ESD and transient bursts that need to be considered as well as the environmental conditions such as temperature, humidity and shock and vibration.

The continuous input voltage range of 16-160VDC and transient operation to 14VDC offered by the RDF series of 25 and 50W rail DC-DC converters covers all standard traction nominal battery voltages with the just one compact device. The units are compliant with EN45445-2 fire protection requirements, operate in ambient temperatures from -40 to 100degC and, with the addition of a minimum of external components comply with the latest electromagnetic compatibility standards.

The RDF25 comes in an industry standard 2”x1” PCB mount package with an option of an additional factory fitted heatsink to extend the temperature range for full power.

• Regulated Single Output
• Covers all nominal inputs from 24 to 110 VDC for Railway Applications
• Wide 10:1 Input Range
• 3000 VDC Isolation
• High Efficiency
• EN50155 Certified for Railway Applications
• EN50121-3-2 with External Components
• Remote On/Off
• Output Voltage Trim ±10%
• Operating Temperature -40 °C to +100 °C
• Full Power to +55 °C
• 3 Year Warranty

The RDF50 uses a standard ¼ brick baseplate cooled package allowing the full 50W of output power to be drawn at baseplate temperature to 100degC across the entire range of traction nominal battery supplies.

• Ultra Wide 12:1 Input Range (14-160 VDC)
• Single Output
• Industry Standard 1/4 Brick
• -40 °C to +100 °C Operation
• 3000 VDC Isolation
• Output Trim -20/+10%
• Remote On/Off and Remote Sense
• Complies with EN50155
• Meets EN50121-3-2
• 3 Year Warranty

Proven solutions based around these products are provided for EMC compliance with detailed reports from independent certified test laboratories to ensure easy integration into the end application regardless of the environmental & mechanical requirements of the final mounting location. These standard, off-the-shelf modules are either integrated directly into the end equipment or used as building blocks to provide complete centralized power solutions across all of the common traction power platforms with the low risk and fast time to market required in often project based system developments.

The new CMP250 series of high peak-power AC-DC power supply units have been developed to support a wide range of healthcare, industrial and IT applications. With a highly flexible combination of electrical and thermal characteristics, these power supplies deliver up to 500 Watts of peak power for up to 60 seconds, as well as providing up to 250 Watts of continuous convection-cooled power. This flexibility makes the series ideal for motor applications and other electromechanical loads without the need for fan cooling, removing unwanted audible noise, across a range of applications.

For healthcare applications, the CMP250 series provides input/output (I/O) isolation of 4 kVAC with 2 x MOPP (Means of Patient Protection). The power supplies also provide 1 x MOPP isolation from both input to ground and output to ground, all rated at the AC input voltage. Maximum earth leakage current of 250uA coupled with patient leakage current of less than 80uA combined with these isolation characteristics make the CMP250 an ideal choice for Body Floating (BF) applications, targeting a range of equipment such as surgical tools, motorised beds, and chairs, use in life support, imaging and blood processing products.

The CMP250 also supports wide a variety of industrial and ITE applications, especially supporting those applications that have requirements for long-duration peak currents to drive equipment such as printers, motors, and electromechanical devices.

The supply’s peak-power capability of 500 W significantly reduces cost in medical devices and industrial equipment compared to implementing a power supply that is rated for continuous operation at more than 250 W. Operating over a wide –40°C to +70°C temperature range with no derating until the ambient temperature is above +50°C, the series offers a high typical efficiency of 89% along with a very flat efficiency curve across the entire load range. The efficiency performance means less dissipated heat enabling the convection-cooled design and negating the need for system fan cooling.

Supplied in a low-profile 1U-high chassis and 7.5 x 4-inch footprint and operating from a universal AC range of 80 to 264 VAC, the series is available in three different models, offering outputs of 24, 36 or 48 VDC.

Key features include constant-current overload characteristics to support a wide variety of loads, a 5V standby output rated at 1.5A, present whenever the AC input is applied, and a 12V/0.6A auxiliary output. Signals and controls include remote sense, output inhibit, AC OK/Power Fail signal and the ability to current share up to three units in parallel. This fully featured supply provides an array of options which, coupled with excellent EMC performance and approvals to the very latest safety standards, ensures easy integration for the end equipment designer.

Component high voltage output DC-DC converters have changed the way many manufacturers implement and use high voltage in their products. These standard high voltage DC-DC converter modules are miniaturized, PCB-mounted, encapsulated, low noise assemblies generating a high voltage output that is fully controllable using standard low voltage circuitry.

Figure 1: Component, high voltage DC-DC converters generate a high voltage output that is fully controllable using standard low voltage circuitry.

Standard high voltage DC-DC modules are divided into two specific groups: proportional and regulated.

Standard proportional parts provide versatile low cost DC to high voltage DC conversion. The output voltage is directly proportional to the input voltage, with the best products providing the proportional output over a wide input range from 0.7V to the maximum input. The high voltage DC output is controlled by varying the input voltage rather like a high voltage DC transformer.  Many proportional modules provide isolation of the output voltage from the DC input, allowing both positive and negative supplies to be generated from the same module and allowing for the high voltage output to be offset as.

Applications requiring close control over a wide DC input range, such as a battery supply in a portable application, or over a wide load range, require a regulated DC to high voltage solution.

Standard regulated DC to high voltage DC modules feature easy, linear and accurate low voltage external control, typically via a 0–5V control input. They provide a stable, low noise, high voltage output over the specified input voltage and load range, fully programmable from 0–100% of the nominal output voltage via the linear low voltage control input. Additional features include signal level voltage and current monitors and reference outputs, which are readily interfaced with standard low voltage circuitry.

The alternative approach to the regulated module, particularly where input-to-output isolation is required or desirable, is to take a standard proportional module and implement an external control loop which monitors the output voltage and compensates for load changes either by adjusting the control input or by adjusting the input to the module itself via a low cost, low voltage, pre-regulator stage. Design information for such control schemes is generally available to users from the module manufacturer.

When taking a distributed power solution approach, power system designers can simply plug in a miniature high voltage module and locate it precisely where the high voltage supply is needed, eliminating the need for a bulky, chassis-mounted, custom high voltage power supply. Alternatively, these miniature, versatile modules can be used as building blocks to provide solutions to bespoke power needs in a centralized power solution, which can also include low voltage power outputs for system controls, without the risks associated with ground-up custom design of the high voltage power stage.

Standard off-the-shelf high voltage DC-DC converters offer power system designers a number of compelling benefits:

1. 1. Reduced design cycles
          Using high voltage modules eliminates the time required to either qualify custom high voltage power supply or for equipment designers to research, develop and verify the entire supply themselves. Changes in output voltage or power levels are easily made at any time during development or implemented for system options, without incurring additional lead time for the variations and accelerating time to market.
   2. Reduced size and weight High voltage DC-DC converters occupy significantly less space than traditional high voltage designs due to the advanced materials and packaging utilized in miniaturizing the device. This leads to additional space for enhanced system features, reduction in the size of centralized power solutions and potential reduction of overall system volume. The materials and processes used in the manufacture of high voltage modules are well proven for long term reliability, with products available over a wide range of voltages and power levels.
   3. Reduced development and manufacturing costs
          PCB-mounted modules generally do not require hardware for chassis mounting or hand wiring, speeding up assembly and reducing the risk of error. Users benefit from the economies of scale, since standard high voltage modules are already being produced in higher volumes and are priced accordingly. The use of standard products reduces the risk of reliability issues as the design is qualified, verified and has demonstrated reliability.
   4. Increased flexibility    Modifications and application specific variations can be generated rapidly with little or no risk based on a proven base design and construction. Common packages and footprints among different products ease voltage or power changes during system development.
   5. Agency approvals
          Most standard high voltage modules already have regulatory approvals, making the approval process quicker and easier.

All of the benefits outlined above are equally applicable to bespoke power solutions derived using the standard high voltage modules as building blocks, whether for in-house development by the end system designer or for those undertaken by the module manufacturer itself.

XP Power’s engineering services group is a good example, taking the end equipment manufacturer’s system specification requirements and producing a drop-in, application specific sub-assembly for easy integration without the risks associated with ground-up high voltage power design. Typical solutions include AC input supplies, specific mechanical design and packaging, control electronics, interfaces, signals and alarms, the ability to reverse the high voltage supply, digital communication interfaces and the ability to combine both the low voltage and high voltage demands of a typical end application from a broad standard product portfolio.

XP Power offers a broad range of DC to high voltage DC converter modules with output voltages from 100V to 10kV in both proportional and regulated topologies for use as stand-alone modules by the end equipment manufacturer or integrated into application specific assemblies.