EMC TESTING: POWER CONVERSION
❱❱ Heavy lift military aircraft like the Lockheed Martin C-130 Hercules
transport plane, below, have demanding requirements on stable, reliable AC/DC conversion systems and the PS11200 3-phase AC to DC power
conversion instrument meets the size, weight and power-balance required, inset
3-phase supply qualifies for heavy aviation
product range for power conversion applications. This switch mode power supply (SMPS) offers 11,200W of fully isolated output power with 91 per cent efficiency at full load. It is designed to replace legacy 400A systems that generally produce unregulated or loosely regulated power in a larger footprint. Marotta has also confirmed that the PS11200 has passed all necessary tests to ensure the power converter’s reliability and performance within rugged environments commonly presented by heavy-lift military or defence aircraft such as the C-130 Hercules cargo aeroplanes and the CH-47 Chinook transport helicopters, as well as unmanned aerial vehicles. Historically, multiple steps are required
A
to convert 3-phase AC input power to an isolated and regulated DC output with power factor correction. Each conversion step adds its own complexity and components, contributing to a loss of efficiency as well as an increase in bulk and weight. In turn, designers make difficult trade-offs in size, weight, power and cost. The 1-STEP range of AC-DC converters was designed to minimise these
merican power engineering specialist Marotta Controls has achieved final qualification of the PS11200 power converter, the fourth variant in the 1-STEP
A 3-phase, AC-to-DC power conversion system is now available with 11.2kW of 28VDC regulated output power for use in demanding aviation applications
compromises for the aerospace industry, where it is often hard to effectively trade between size, weight and power. A 1-STEP converter is an innovative power device that achieves active power factor correction (APFC), output voltage regulation and electrical isolation in a single conversion step. Delivered in a compact lightweight package that can be up to 30 per cent lighter than similar instruments, it meets key military and commercial avionic standards while delivering increased efficiency and power density. According to Michael Germinario, senior technical director at Marotta Controls, the company first launched the product family in 2016 to meet the equipment requirements for regulated DC power on a wide range of aerospace, ground and marine systems.
“But up to that point, available systems had been cumbersome and costly,” he says.
“End users were searching for an alternative that would efficiently result in a 3-phase system that delivers unparalleled power density in a simplified design capable of supporting a wide range of output power. The PS11200 now fulfils that need by bringing technical innovation to heavier load power conversion applications.” With an input 3-phase voltage of 115VAC within a frequency range of 50-800Hz, the PS11200 power converter weighs 34lb (15.4kg) and has an output voltage of 28VDC ± 1 per cent with a power factor correction greater than 0.95 at half to full load, meeting the power quality requirements of MIL-STD-704A-F. The PS11200 is part of the 1-STEP family that includes 1500W and 2600W models at 270VDC and a 3500W model at 28VDC. The device has passed qualification testing against the military EMC standard MIL-STD-461-G for conducted and radiated emissions as applied to electrical equipment installed in fixed-wing naval or air force aircraft. Similarly, it has successfully undergone
environmental testing to MIL-STD-810F and has an operating temperature range between -51°C and 71°C up to an altitude of 35,000 feet. It has been through 20g 11ms shock tests and vibration testing at 5.4grms, 20-2000Hz with 81Hz harmonic peaks. T&TH
March 2021 /// Testing & Test Houses /// 29
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