A Maximum Power Tracker for Improved Thermophotovoltaic Power Generation

Radioisotope Power Systems (RPS) are critical for future flagship exploration missions in space and on planetary surfaces. Small improvements in the RPS performance, weight, size, and/or reliability can have a dramatic effect on the scientific capability of the vehicle and the overall mission costs. Radioisotope Thermophotovoltaic (RTPV) energy converters are a particular type of RPS that directly converts the heat produced by a General Purpose Heat Source (GPHS) to electrical power using a specialized Photovoltaic (PV) cell. A key element in an RTPV system is the power conversion electronics system that efficiently converts the low-voltage current from each PV cell into useable, stable bus voltage for powering spacecraft systems despite issues such as non-uniform illumination, PV cell degradation, and decay of the GPHS source. In this project, Creare and the Massachusetts Institute of Technology (MIT) propose to develop an advanced, multi-channel maximum power point tracking module (MPPT) that is optimized for RTPV systems. The converter will provide stable output voltage from a 16-cell PV array that, when coupled with advanced PV technology of the RTPV system, will provide high system efficiency. In Phase I, we will design a prototype power tracking module, which will be fully characterized for conversion efficiency. We will also assess the impact of this new MPPT on the overall RTPV system design and performance.