HVDC to DC Conversion Solutions

Cyient has developed a technology solution for HVDC to DC conversion with optimized size, weight, power dissipation, and cost (SWaP-C) benefits as part of its CyientfIQ^TM innovation platform. This was accomplished by active clamp forward converter topology, integrated driver, built-in isolation, high-frequency switching, planar transformer technology, and encapsulated packaging. This solution will accelerate the development of power conversion products for our customers across industries.

In aerospace DC power distribution/centralized converter application, the power is conventionally distributed at low voltage with high current over long distances to the loads. This results in bigger, longer, heavier cables, higher power loss, a bulky system, and hence a higher cost of ownership.

A decentralized converter offers a superior alternative to distributing power at low voltage over long distances. Here, high voltage can be distributed with lower current, and multiple HVDC to DC converters are used at the load end as shown below.

In telecom, industrial, and rail power supply applications (HVDC input and control power supply outputs), existing power supply assemblies are bulky and inefficient due to conventional design and outdated technology components. Utilizing the active clamp forward converter topology, integrated driver, built-in isolation, and planar transformer technology makes the power supply more efficient and compact.

Additionally, across industries, there is a need for efficient and high-power density (i.e., higher power vs. size ratio and higher power vs. weight ratio) HVDC to DC converters.

HVDC to DC Conversion Solution

Cyient’s HVDC to DC Conversion solution delivers SWaP-C benefits using the unique technologies described below.

Active clamp, synchronous forward controller topology which has Current-controlled operation, Integrated drivers and Built-in magnetic isolation
Planar transformer
Efficient thermal management techniques utilizing thermally conductive, electrically insulating encapsulation with gold-plated aluminum casing
High-frequency switching (550KHz)

An active clamp, isolated, synchronous forward controller eliminates bulky signal transformers and optocouplers that transmit signals over the isolation boundary. Integrating the couplers and internal drivers reduces system design complexity, cost, and component count and improves overall system reliability and efficiency.

The planar transformer utilizes winding of the transformer on a multi-layer PCB, which provides significantly low height (low profile), smaller winding area, excellent thermal characteristics, low leakage inductance, excellent repeatability, and reproducibility.

The converter design uses high-frequency operation, which helps in reducing the filter component size.

Encapsulation of the converter in a potting material provides environmental protection. The thermally conductive, electrically isolated potting material reduces hot spots, levels out the thermal gradients, and transfers heat from switching devices to an externally mounted gold-plated aluminum case.

Benefits

Higher power density of 0.5W/g

Output (60W)
Smaller size: Quarter brick (11mm X 64mm x 38mm)
Lower weight (120g)
Lower power loss (> 85% efficiency)

Lower carbon emission

Low component count and thus higher reliability

Multi-utility

Wide range input 190V to 425V
Compliant with a wide range of aerospace/military standards such as DO-160G, MIL-STD-810F, and MIL-STD-461F with external filter

High Voltage DC to DC Converter