Clean Growth strategy presents opportunities for innovation in Power Electronics Machines and Drives

KTN’s Knowledge Transfer Manager for Electronics, Paul Huggett, looks at opportunities for low carbon electrification.

Clean Growth has been identified as one of the four Grand Challenges in the UK Government’s Industrial Strategy. It simply means to achieve economic growth using clean technology and sustainable development whilst reducing greenhouse gas emissions.

Electrification offers a significant opportunity to accelerate the move away from carbon intensive energy to low carbon alternatives. The Government aims to phase out unabated coal fired electricity generation by 2025, with shortfalls made up through low and zero carbon generation such as solar, wind and biomass and non-renewable gas and nuclear. The first three of these have by nature a much lower areal density than the last two. This low density manifests itself as ‘Distributed Generation’, in which multiple small sites contribute to local generation, distribution and consumption, a model for which the electricity networks are poorly adapted having derived from the central generation model.

Technologies which will experience significant innovation include:

• Automotive and rail move from thermal to electric traction
• Aerospace move to more electric propulsion and actuation
• Energy Generation away from thermal to non-carbon sources
• Energy Generation and Distribution from centralised to distributed connections
• Energy storage to for local storage and vehicle to grid support
• Built environment with low carbon electricity heating and lighting
• Industrial Drives will require efficient and economical controls

All of these innovations are predicated on efficient, reliable and cost-effective power electronic systems.

Power Electronics Machines and Drives (PEMD)

PEMD technologies provides the means by which electrical energy can be controlled, converted and conditioned in all of the above examples including the conversion of electrical to mechanical energy in rotating machines. This is displayed graphically below.

Image courtesy of Electrical Mastar, Online Electrical Library

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The UK Power Electronics supply chain supports 82,000 high value jobs in design and manufacture, of which 50,000 are at graduate level, and underpins a £49bn contribution to GDP. The R&D know-how in the UK encourages international companies to foster high value-add activities in the UK. Crucially, a major portion (approx. 95%) of the power electronics designed and made in the UK goes to export. (source: Powerelectronics UK White Paper 2017).

Silicon Power Devices

Silicon based power devices are the incumbent technology with a considerable legacy. They will remain the prominent technology in the short term (5 years) due to their acceptable performance, low unit cost and continued development, in particular in implementation of novel machines and drives topologies. The Global Silicon Power MOSFET Market is expected to attain a market size of $6 billion by 2023, rising at a market growth of 7.7% CAGR during the forecast period.

Compound Semiconductor Power Devices

Wide bandgap (WBG) compound semiconductor power electronics are a small but growing segment of Power Electronics and can be expected to comprise over 12% of the PE market by 2025.

This growth is being driven by demand for smaller packaged electronics with increased power density and higher efficiency. Replacing silicon with a WBG semiconductor can yield higher breakdown voltages, faster switching, lower switching losses, and higher operating temperatures. Through careful design, all of the attributes and trade-offs can lead to power conversion products that have higher power density (more efficient and smaller), weigh less and may even cost less. Source: Wide Bandgap Semiconductor Opportunities in Power Electronics, commissioned by US Department of Energy.

The UK has a strong legacy and current investment in the development of compound semiconductors for applications in healthcare, the digital economy, energy, transport, defence and security, and space sectors. The growth in these sectors is driven by both the evolution from “traditional” compound semiconductors materials such as Gallium Arsenide to the development of “new“ materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) which have greatly accelerated the development of high power, voltage and frequency electronic devices.

Semiconductor Independent Aspects

Whilst new semiconductors are fundamental to the step change in performance, this performance indicates step change improvements in associated technologies such as:

• Optimisation and integration of passive devices (inductors and capacitors) into power electronic systems
• Improved magnetic materials or design for next generation PEMD systems
• Improved gate, control and current sensing within power semiconductor systems
• Improved models for accurate simulation ‚Äì including design and multi-physics modelling.
• Techniques to predict device and component reliability and life-time performance
• Improved thermal, voltage and EMI design, performance and management
• Innovative packaging techniques, including 3D integration and new materials.
• Improved short-circuit system design and performance.

Electrical Machines

Traditionally electric machines or just plain motors were a relatively constant feature of PEMD technology with design and performance and application determined largely by electrical and magnetic configurations and available supply voltage and frequency.  The development of semiconductor controls able to efficiently switch high power at variable frequency has allowed the machine designer to adopt novel motor topologies taking advantage of much more efficient, flexible and application specific performance.

KTN is supporting a number of PEMD related activities both through the day-to day-networking activities and also the Compound Semiconductors Special Interest Group

Sign up and receive news and invitations to a number of events we have planned over the next 12 months. Topics include:

• Non Semiconductor Materials for PEMD including Magnetics/Inductors,¬†Dielectrics/Capacitors, Thermal Materials, Cables & Connectors
• Materials for Compound Semiconductor Wide Band Gap Devices
• CS Electronic Design Systems

KTN is also supporting the research base through the EPSRC Centre for Power Electronics Project and related Advanced Propulsion Centre Spoke programme and continues to support the mid TRL activities of the Compound Semiconductors Applications Catapult.