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POWER Research Focus Areas

POWER Center brings together a convergent team of researchers and disciplines from academia, industry, non-profits, national labs, government and other stakeholders.  While the center recognizes the importance of the science behind WPT, it is also aware that the social transformation and safety of these technologies need to be understood and researched as well. Following the team meeting in Falls Church, VA, in Sept. 2017,  a series of discussions were held across the nation to address the WPT technology space in a comprehensive manner. Team building steps led to a national workshop hosted at Penn State on October 23-24, 2018, to finalize the technological barriers, fundamental solutions, technology roadmap, intellectual propertypolicy,healthandsafetyissues,andhuman–technology interactions. Following this national workshop, an industry workshop was held in Arlington, VA, on Dec 18, 2018, that provided guidance on roadmaps, workforce development, IP policy, project management, etc. Based on advanced planning for the center, research is organized into three testbeds and five thrusts.

Proposed Testbeds

Testbed 1 – Powering implantable and wearable devices: The next decade will see proliferation of implantable and wearable devices for health monitoring, assistive/rehabilitative devices, restorative prosthetics, disease management, and bioelectronic medicines. Dependence on batteries is a serious limitation for these devices. Our goal is to develop a wearable/implantable medical device WPT ecosystem that is both safe and convenient. For example, we envision safely and automatically recharging medical implants/wearables during the night while a person sleeps or continuously transfer wireless power to deep (several centimeters) tiny (sub-millimeter-sized) implants that cannot carry a battery. We plan to develop ultrasonic WPT links that can deliver power using an (or an array of) ultrasound transmitter(s) and acoustic receivers. MEMS-based electromechanical power receivers will generate power from ultra-low-frequency magnetic fields at distances of tens of centimeters. Mechano-magneto- electric (MME) mechanism will be investigated to implement high power density receivers. Investigations will include designing, synthesizing and characterizing new MME materials and implementing them into tailored device architectures.Safety and potential side-effects (heating, neural stimulation, etc.) of these new WPT mechanisms will be systematically assessed. We will undertake research towards the application of transfer power measurement to accurately determine the real power absorbed by biological tissue from WPT. To enable modular systems, application-specific integrated circuits (ASICs) for dedicated functionalities will be developed and integrated into a combined System in Package (SiP).

Testbed 2 – WPT for industrial and built-environment automation: Industry 4.0 is driving the automation and data revolution in manufacturing, home and work environments. To address these emerging social and economic “smart” and automated environments, Testbed 2 will demonstrate novel solutions for addressing the limitations of both near-field and far-field WPT. New composites and meta-materials will be developed for significantly increasing the distance-efficiency product, shielding fields from interfering metallic structures, and increasing human safety. Proposed transformational metamaterials are 3-D structures whose permeability/permittivity can vary arbitrarily in space to focus and redirect fields for greater coupling and reduced interference. Spatially Programmable Rollable Inductive Transmitters (SPRIT) will be developed to maximize power gain (efficiency) over a large area, and to mitigate health hazards. Tunable materials will be integrated with the recognized Power Electronic Building Blocks (PEBB) to synthesize Tunable Electric Building Block (TEBB) that, e.g., adaptively matches SPRIT to dynamic load, source, and coupling. Far-field approaches will be developed for wireless sensors. Various technological issues will be addressed including multipath fading in indoor environments, efficient rectification of multiple dynamic modulated signals when harvesting or power-on-demand, diode with zero turn-on voltage (not just zero-bias), simultaneous and selective powering of multiple sensors, low-power authentication, powering and transmitting/receiving data using the same hardware, radiated EMI analysis and reduction, and heterogeneous integration. Additionally, a multi-mode cavity with mode-mixing will be developed to effectively power multiple devices simultaneously in a shielded environment and without the need for special alignment. Enabling magnetic and dielectric materials will be explored with tunable RF properties and capability for low loss and high permeability / permittivity values retained at frequencies approaching the GHz range.

Testbed 3 – Dynamic charging of electric vehicles: By 2040, 55% of new car sales and 33% of the global fleet is projected to be electric, providing an enormous opportunity for US industry. Our focus is on “moving and charging,” as compared to “parking and charging,” to enable unlimited range and reduce vehicle costs by minimizing onboard batteries. Both inductive and capacitive approaches will be investigated (Fig. 2). Capacitive WPT systems promise higher tolerance for misalignment and foreign objects, operation at higher frequencies, and relatively smaller size and cost. Our team’s innovations in multistage matching networks, novel approaches towards handling the parasitic capacitances in a charging environment, and MHz-frequency soft-switching power conversion will be leveraged. Thrust 1 team will develop materials, components and technologies needed to enable effective dynamic EV charging. In addressing the limitations of current inductive and capacitive WPT systems, novel magnetic materials with higher saturation flux densities and improved loss characteristics at higher switching frequencies will be developed. Tunable high-power high-frequency components will be developed to provide enhanced matching at high efficiencies and high-power densities. The research will include the development of adaptive power electronic circuits that leverage these components to manage the variability of moving vehicles with different road clearances, and the investigation of appropriate control algorithms. Electromagnetic interference (EMI) issues will be addressed using innovative near-field focusing techniques. WPT infrastructure on highways powered by locally generated renewable energy would enable battery pack downsizing, but system architectures will need to be developed to minimize the number and depth of charge/discharge cycles that these smaller battery packs need to undergo. Wireless Information and Power Transfer (WIPT) will be investigated and demonstrated to revolutionize self- driving and self-charging autonomous transportation. Penn State Larson Transportation Institute Test Track, PennStart and MCity will provide full scale testing capability.

Schematic representation of the dynamic inductive and capacitive charging
Schematic representation of the dynamic inductive and capacitive charging

3-Plane Strategic Planning Chart

3-Plane Strategic Planning Chart

Proposed Thrusts

Thrust 1 –Multi-scale materials and components to break the power– frequency–efficiency trade-off - New tunable dielectric and magnetic materials will be developed for higher power, temperature and frequency operation, which will increase both energy and power densities of passives while significantly reducing the cost. Efforts will be made towards the development of tunable inductive/capacitive modules and integration of the tunable modules with power switches and controllers to form TEBBs. The TEBBs and SPRITs will join the suite of functional blocks (for intelligence, communication, thermal management, etc.) that reduce materials, labor, and cost of manufacturing wireless converters and systems. Additional emphasis will be on cooling and thermo-mechanical reliability. Advanced manufacturing approaches such as in-line processing with integrated coatings and thermal- mechanical or thermal-magnetic processing techniques will be exploited for scalable production of tunable components. Tunable metamaterials will be developed for Testbeds 2 and 3 where wireless power must be transferred around building structures and through biological tissues. New class of transformational metamaterials will be enabled by new insights in field shaping and shielding and 4D additive manufacturing. High-power and high-frequency semiconductor devices will be developed for transmitters and receivers with switching frequency up to 100 MHz and power level up to 100’s of kW. In addition to GaN and SiC, we will explore the next-generation of wide bandgap materials such AlN, high Al- composition AlGaN, and Ga2O3. Both heterogeneous and monolithic integration approaches will be investigated to minimize parasitic issues, reduce size, scale output power and minimize cost.

Thrust 2 – Understanding the influence of dynamic electrical power on human health to inform standards and policies - In the case of automotive charging or industrial automation, potential hazards will have to be understood and evaluated through case studies. In the case of charging of wearables/implantable devices, a human will be directly immersed in the charging field, and this exposure can interfere with tissue homeostasis. Furthermore, unwanted stimulation of the nervous system could impact neural functions and the pathogenesis of neurological diseases. Interaction of electromagnetic and acoustic waves with cells and tissues depends on their biological and physicochemical properties, including cellular composition, microarchitecture, thermal conductivity, blood perfusion, and electrical conductivity. The activities undertaken under this thrust will address the safety of WPT technologies in compliance with regulatory standards/guidelines (FDA, FCC, IEEE, ICNIRP, ASTM, and ASME). These efforts will lead to a national standardized testing facility. Fully coupled multi-physics voxel models with realistic anatomical and physiological information will be developed. Models will analyze wave propagation and loss in tissue, resulting specific absorption rate (SAR) and tissue heating. Standardized ex vivo models will be developed to evaluate effect of WPT technologies on cell and tissue functions incorporating factors such as operating frequency, power level, depth of implantation, SAR/field/dosimetry, MRI compatibility, etc. Test setups will be developed to assess the shielding effectiveness of wearables for both near field and far field. Appropriate animal models will verify in vitro findings of the developed WPT technologies according to the above-mentioned engineering/physical/physiological metrics. The results of such assessments and studies will have implications in terms of the methods of device implantations and/or other medical considerations. Identified safety protocols will be communicated to governing bodies to update the standards such as IEEE standard C95.1, ASME V&V 40, ASTM F2182 – 11a and ISO/TS 1094.

Thrust 3 – Techniques, circuits and systems for intelligent and highly integrated wireless power management, conversion and transfer - An ambitious goal is to explore multiple access WPT via reconfigurable peer-to-peer power transfer networks. The research in this thrust will include circuits, systems, and theory of code-division multiplexing (CDMA) for many-to-many WPT toward higher efficiency and higher frequency to push the frontiers of scalability, miniaturization, and range. Investigations will result in a platform for many-to-many WPT that is more scalable, cybersecure (authenticated, resistant to jamming, interference, disruption, and overloading), and resilient compared to other methods for multiple access. WPT-CDMA has potential applications in body-area networks, sensor (including medical) networks, RFID, and other IoT applications. To achieve high efficiency and required power, we will develop “smart” power converters that are capable of adaptively and dynamically reconfiguring their structures to compensate for environmental and electronic variations such as coils/plates/transducers distance, alignment, and orientation changes, resonant frequency changes, load changes, etc. We propose to innovate methods for closed-loop control between the transmitter and receivers such that the transmitter can dynamically alter its transmit characteristics, and the receiver has the required power and voltage to achieve its operation without complex and bulky onboard power management circuitry. A wireless Hardware in the Loop laboratory will be developed that will enable characterization of tunable materials in a circuit/system like environment, testing of conceptual adaptive control schemes at the IC level for optimization of energy transmission/reception, early experimentation and behavioral analysis of novel power converter topologies. Thermal analysis and multi-physics simulations will be conducted using multiscale modeling techniques, where the goal will be to develop a robust simulation architecture that can connect all the way from materials to components to circuits.

Thrust 4 – WPT system integration, infrastructure, and regulations - Research under this thrust will focus on integrating WPT with existing energy systems, e.g., buildings (and communities of buildings); the electric power grid; and energy storage systems. From an architectural design perspective, WPT technology is disruptive with impacts on all scales: buildings, cities, and landscapes. We will investigate how buildings and cities will look like in the future. An interdisciplinary design studio will be developed aimed at designing a building or a community permeated with WPT technology. In doing so, we will also consider power grid planning and operational models that are informed by the nature of WPT demand as suggested by other thrusts, and also informed by mobility information from transit and mobile phone data. Research questions include: What are the infrastructure deployment needs to meet varying levels and modes of WPT demand? How can wide-area WPT be used as a distributed mechanism to absorb fluctuations in large-scale grid-connected wind and solar power, thus reducing renewable integration costs for grid operators while simultaneously providing an always-on charging service for EVs? What does an optimal WPT dispatch strategy look like, and how does such a strategy vary by end-use application? Is ‘always-on’ WPT sensible, or can the impact on the power grid be reduced without adverse effects on electricity consumers by controlling real-time power transfer in some way? Charging a moving EV brings significant challenges with respect to storage. POWER Center will leverage supercapacitors to batteries and innovate design of battery pack, including estimation, series string balancing, and thermal management.

Thrust 5 – Inclusion of education, technology-adoption, and social aspects in design of testbeds - (a) Social Science and Policy Research: Ultimately it is essential that new power technologies are accepted by potential end-users of the technology, as well as by the public more generally. There is a documented history of unease, resistance, and even more extreme responses to new transformative technologies. Even, when evidence convincingly demonstrates product safety, there are sometimes concerns about technology’s effects on health. We will use large scale, nationwide, mixed-methods to investigate research questions such as: How do people perceive and react to WPT? What demographic and psychological characteristics predict acceptance or rejection of new technologies associated with POWER outcomes? What communication interventions can be developed for stakeholder groups to diffuse concerns? What are the economic and social impacts of WPT technologies downstream of technology adoption? What legislation will be required to scale up WPT technologies? (b) Engineering Education Research: A variety of foundational engineering education research questions will be considered, employing multistage mixed- methods across collaborating institutions and industry partners. Research questions that will be addressed surrounding graduate students, industry partners, and faculty include: How do undergraduate and graduate students develop engineering identities within emerging technological research areas? How do graduate students socialize into academic norms via inter- and multidisciplinary research? To what extent are the dedicated mentoring activities infused through POWER influencing the retention of women and underrepresented minority students to and through graduate school and/or to faculty or industry careers? At the K-12 level: How do teachers learn about the disciplinary content and practices of engineering through professional development? How do teachers engage students in the practices of engineering? How do students learn and participate in the practices of engineers through classroom research projects?