Mil-Std_704 3ph AC power at up to 12kW
Revolutionary Model-Based Design transforms our Engineering
Raytheon UK makes formidable foray into model-based design with its PhantomStrikeTM radar system Power Conditioning Unit
When Raytheon UK Engineering Fellow Dr. Grant MacLean set about transforming Raytheon UK’s approach to advanced design, research and development using model-based design, he knew he was on to something groundbreaking. If successful, applying emulation techniques – i.e. the model generating physical signals to bridge the gap between simulation and the real world – to power product development would help predict customer’s future needs whilst mitigating programme risk.
Building the expertise to fulfil this vision took patience, but the strategy, which began in 2017, is paying off. Raytheon UK has been awarded a multimillion pound production contract for its PhantomStrikeTM Radar System Power Conditioning unit (PCU), developed using model-based design. Compatible with a wide range of platforms – including light-attack aircraft, rotary-wing aircraft, uncrewed aerial vehicles, and ground-based towers – this first-of-its-kind, compact Active Electronically Scanned Array (AESA) radar is smaller, lighter, quieter and requires less power.
“Eight years ago, we began to consider the type of power supply customers might require in the next three-to five years and decided on investing R&D into a small, flexible AC to DC Power Converter, particularly for military and civilian radar,” said MacLean, an RTX-certified architect.
“Military and civilian aircraft electronic systems derive power from turbines that produce an AC, or a three-phase, effect. However, customers will always need to convert AC to DC power because that’s what a lot of their systems run on. To do that in an aircraft is a challenge because any technology placed in an aircraft needs to take up very little space and weight,” said MacLean.
Raytheon UK’s PhantomStrikeTM radar system Power Conditioning Unit
Model-based design would allow the company to de-risk its investment.
MacLean brought the University of Strathclyde onboard in 2017 to help evaluate these new tools and methods of design with the objective of delivering a physical model. By 2020, the team had succeeded in creating an Active Rectifier Technology Demonstrator in Raytheon UK’s Glenrothes lab that would form the basis of future three-phase AC-DC Power supplies up to and beyond 12kW, including the PhantomStrike programme.
Raytheon UK’s core Active Rectifier technology is a device that uses actively controlled switches, rather than passive diodes, to control the currents in a system. The greater control means that greater efficiencies can be achieved as well as reducing the size of the system overall.
Specifically designed for PhantomStrike using Raytheon UK’s core Active Rectifier technology, the function of the PCU is to form the primary power conversion interface between the aircraft primary power system (AC power from the engine-powered generators) to supply regulated, conditioned DC power to the PhantomStrike AESA Radar Unit and the PhantomStrike Compact High-reliability Integrated Receiver/exciter Processor Unit.
“The PCU has been tested under a wide range of simulated conditions that would conventionally take significant effort to perfect with physical bench-testing,” said Dr. Puran Rakhra, principal systems engineer who co-led the PhantomStrike PCU programme along with Dave Gordon, chief engineer and engineering fellow.
Rakhra was formerly the research associate at Strathclyde University working on the active rectifier topology and was recruited into Raytheon UK’s engineering team.
“De-risking our PCU model within a digital twin, model-based environment was key to its success. The model also formed a platform by which we could better execute further refinements to the PCU requirements associated with functionality, signalling and timing that brought benefits at the PhantomStrike integrated system-level with the CHIRP and radar units.”
The resulting radar weighs less than 150 pounds – nearly half the weight of more traditional radar systems – and delivers the advanced performance needed for superior battlespace situational awareness.
The Active Rectifier & Controller within PhantomStrike PCU provides:
Includes EMI Compliance to Mil-Std-461
Efficiency: >97.5%
Power density: ~3kW/kg
High Accuracy, Low risk
Model-based design enables development to be much more methodical, rigorously tested and therefore much more accurate and predictable. The PCU team can trial proposed hardware improvements with high-accuracy tasks since the model – a digital twin – has identical behaviour and timings to the real-world hardware.
“PhantomStrike has been designed to suit multiple aircraft and several different radar arrays. It’s therefore important that firmware can be updated and modified, at low risk in the future to allow variants of the PCU suitable for other platforms. This lends itself to the model-based environment where it is reasonable to expect that a new engineer can later modify code while understanding relationships and potential risks,” said Gordon. “Ultimately the new performance can be compared with a prior benchmark, further reducing risk before delta qualification.”
“It’s manufacturing for the future, and the future is now"
- Dr. Grant MacLean, Engineering Fellow
MacLean is pleased that PhantomStrike’s success has led to other Raytheon UK programmes adopting model-based design.
“For most product design teams, even some engineers, the power supply is not the sexy bit of what they’re designing. In fact, it’s fundamentally critical to a system in terms of its size, weight and power, and therefore the system is often defined by the design of the power supply itself,” he said
While the team is focused on the contract at hand, they believe that there will be great interest in the same technology due to its flexibility and scalability.
“Our PCU is going to be on multiple platforms and many different aircraft that houses this radar system, and that’s significant,” said MacLean.
This the first Raytheon UK programme to utilise model-based design, and he believes that it is giving the company the competitive edge. “It’s manufacturing for the future, and the future is now, said MacLean.
Raytheon UK’s Power Electronics Group has products (power supplies and motor drives) on a wide range of platforms, such as the International Space Station, Tomahawk Missiles, Mk54 Torpedo, Sentinel Aircraft, ATFLIR, Ajax Scout Vehicle and others.