Relec

In the Absence of Catenary Power

Dc-dc converters in Premium’s CBS-10K series, available from Relec Electronics, provide peak power for hybrid diesel-electric trains when catenary power is not available

Electric traction is increasingly common as more rail companies introduce them and government initiatives around the world encourage more environmentally friendly transport systems. In addition to energy efficient operation and reducing CO2 emissions, the electric traction system reduces noise which benefits city dwellers especially those living near train lines. Regional markets for hybrid trains are North America, Europe, Asia Pacific, Latin America, the Middle East and Africa. Demand is expected to recover from the disruption of the covid pandemic and the disruption to manufacturing as new rail infrastructure projects are put in place to ease traffic congestion.

Market growth

Analyst firm, Expert Market Research, predicts that the global hybrid train market will experience a CAGR (compound annual growth rate) of 6.3 per cent between 2022 and 2027. Europe is expected to see significant growth, led by a rise in adoption of hybrid trains in France, Spain, Germany and the UK, says the company in its Global Hybrid Train Market report.

In the electric traction system an electric motor powers the train’s wheels and a diesel combustion engine powers the batteries and the electric motor. The trains can therefore operate on both electrified and nonelectrified track, switching power source as required.

The CBS-10K dc-dc converter

The CBS-10K dc-dc converter can be installed inside the train to transform the battery voltage (110Vdc) to a higher voltage direct current (DC) bus (500Vdc). In catenary operation, the train supplies power to all systems through the dc-dc converter. The dc-dc converters are designed to meet EN50155 for railway applications and rolling stock standards. They are also approved to EN45545-2 (fire and smoke).

At start-up, it supplies the rectifier enabling it to operate as an inverter. It allows hybrid diesel-electric trains to operate at low speeds when overhead electrical wires are not available.

The compact and lightweight dc-dc converters feature galvanic isolation between input and output, operating at fixed switching frequency. The single output dc-dc converter has multiple I/O combinations to a wide variety of rail applications which require high power conversion in a compact design.

The CBS-10K dc-dc converter provides up to 6kW average power and peak power up to 10kW for 40s to protect against overload and short circuits. The modules can provide 500Vdc output and models offering up to 700Vdc are available on request.

Power density

Premium developed the dc-dc converter series based on SiC (silicon carbide) technology, which offers increased power density compared to silicon (Si). Input options are 24Vdc, 48Vdc, 72Vdc and 110Vdc. All models can be operated in

Location of Premium’s CBS-10K in a hybrid traction system where there is no catenary system available.

parallel. The high I/O isolation is 5,000Vrms and the design includes an ORing diode at the output to decouple it from lines up to 2kV.

Other features include opto-coupled remote off and an isolated relay contact alarm. Efficiency is up to 95 per cent and MTBF is 200,000 hours (according to IEC61709, SN29500 at 40°C). The dcdc converters also have remote control functionality via RS232, with CAN bus, available as an option.

The railway module is covered by the manufacturer’s five-year warranty. The CBS10K is also available as an industrial module which has a three-year warranty. Both are available from Relec Electronics.

Rail power expertise

Spanish manufacturer, Premium, was established in 1981 and has a wide range of engineering and power design expertise. As a result, it has a wide range of power supplies for diverse applications within the railway sector. It offers a wide portfolio of high efficiency products, combinations of I/O and input voltage as well as wide operating temperature ranges and a choice of cooling systems. The portfolio complies with railway standards, according to the needs of the application, including IEC safety standards and RIA standards.

Relec Electronics is a specialist in power conversion, based in Wareham, Dorset. It supports its customers with expert technical and design support for Premium’s range of single and three-phase dc-ac inverters, particularly those meeting EN50155 for railway applications and other harsh environments.

It can source and supply a ‘standard’ solution, but its team of engineers also have a broad and deep understanding of railway applications and specifications, enabling them to source the most appropriate products for a project.

The company says it doesn’t only give a customer what they want – it gives them what they need. This sometimes means going the extra mile to customize a product or a feature to achieve optimum performance and service delivery.

Relec applies this philosophy to all product ranges, from ac-dc power supplies, dc-dc converters, displays and EMC filters.

Company profile

Relec Electronics is a specialist in power conversion and display products, representing leading brand names including Bel Power, Mornsun, Chinfa, Cincon, Premium, Advanced Energy (Artesyn and Excelsys) with key display partners, Digiwise and RockTouch.

For over 40 years, Relec Electronics has worked closely with key suppliers and specialises in a wide range of industry sectors, including automotive, industrial, transportation, instrumentation and defence. A team of dedicated engineers is ready to support customers throughout the design process. The company carries stock of all standard modules and accessories for next day delivery. Relec’s team of specialist advisers can refine an initial specification for a given application to include bespoke features to meet the needs of a particular design or project. In December 2020, Relec Electronics became been a UK subsidiary of Gresham Worldwide.

Tel: 01929 555700 Email: sales@relec.co.uk Visit: www.relec.co.uk LinkedIn: Relec Electronics Ltd Address: Animal House Justin Business Park, Sandford Lane Wareham, Dorset BH20 4DY