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The integration of renewable energy sources and the associated power electronics to notebook power and thermal management systems was investigated in this work. Both thermoelectric (TE) and photovoltaic (PV) energy extraction techniques were explored with the goal of achieving best sustainability. Semi-realistic usage assumptions were taken into account to evaluate the merits of the new schemes, along with relevant metrics that encompassed both performance and energy expenditure.
A Thermoelectric System Solver (“TESS”) was developed, and used to simulate the application of TEs to different platform types. The benefit from the three analyzed TE schemes had strong sensitivity to the platform size and material technology. The Hybrid Thermoelectric Conversion (HTC) scheme offered the best tradeoffs, and demonstrated potential for 10% improvement in system efficiency with common TE components, as measured by Performance/Watt. TE module integration into the heat pipe in a standard Thin and Light mobile system was analyzed through a Finite Element Analysis (FEA) model, which identified acceptable module sizes and placements. Next, Photovoltaic Power Generation (PPG) was added by evaluating an integrated PV sheet at the backside of the notebook lid. Available photovoltaic (PV) power range was quantified per system type under realistic use scenarios. Up to 5% battery life extension was achieved using commonly available PV modules.
Power electronics efficiency was highlighted as one of the fundamental challenges in the integration of renewables into a mobile computing platform. The mobile power architecture was enhanced to store the extracted energy from multiple sources in the existing system battery. Using power conversion efficiency metrics suitable for the renewables application, several fundamental topologies were evaluated for stepping up low voltage TE outputs. A cascaded charge pump scheme with an asynchronous oscillator based control scaled best to the requirements of the application, and yielded positive net power generation to the system battery. The circuit contained no magnetic components to be suitable for large scale integration (LSI). Finally, fundamental conclusions from simulations were verified through hardware prototypes using discrete components. |
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