C. Torres’s research while affiliated with Miguel Hernández University of Elche and other places

This work describes the implementation of three Maximum Peak Power Tracking methods devised for small satellites. The three methods are the Analog oscillating Maximum Power Point Tracking, the Analog Global Maximum Peak Power Tracking and the Analog Global Maximum Output Power Tracking. An interplanetary mission (Mars-Asteroid belt) with complex power-voltage solar array characteristics, including several local maximum power points, is considered to evaluate each peak power tracking technique. The three peak power tracking techniques have been integrated in an unregulated battery bus topology using synchronous buck converters as solar array regulators. High reliability design is achieved using analog electronic parts with space-qualified counterparts. Each peak power tracking method has been optimized individually for the best performance and then compared with the others. The experimental validation suggests that the preferred method strongly depends on the expected power-voltage solar array characteristics and mission parameters.

Power distribution using latching current limiters (LCLs) [also known as solid-state power controllers (SSPCs)] is very common for 28- and 50-V bus voltage distribution on European satellite platforms. However, 100-V and even higher voltage distribution platforms generally do not employ the same approach as lower bus voltage platforms since the commonly employed p-MOSFET devices are not well suited for such voltage levels. This work introduces an LCL for 100-V distribution units using a composite power device consisting of a low-voltage p-MOSFET device and a high-voltage, normally-ON silicon carbide junction field effect transistor (SiC JFET). The description of the circuit and the experimental validation using a hypothetical class-2 (2.2–2.8 A), 100-V, LCL is discussed. In addition, in this work, two interesting characteristics are also proposed and validated, and automatic control of the tripping time depending on the overload severity and soft starts for capacitive inrush currents. Robustness and fast reaction, less than 500 ns under short-circuit conditions, have been demonstrated, as well as tight current regulation during overload faults.

This article describes the design and implementation of a dc–dc converter used to power a microsatellite on-board electrolyzer. The proposed topology is a four-phase interleaved synchronous buck converter with output current control. The proposed converter is single point failure free (SPFF), so in case of any individual component failure, the functionality of the system is not compromised. SPFF operation is achieved using individual protections in each buck phase, redundant output current control, and redundant clock systems. Besides, analog majority voter circuits are used to select the correct control signal after any failure and to isolate it. Detailed mathematical analysis and circuit design are presented. Furthermore, a 40-W prototype has been implemented to validate the concept. Experimental results presented show the correct performance of the system in every case and its fault tolerant capability. In addition, the ac behavior and stability of the system have been studied and verified under the full range of possible operating conditions. Finally, efficiency measurements are presented.

This paper details the design and implementation of a photovoltaic current – voltage (I-V) tracer. The I-V tracer employs a capacitive load controlled by a raspberry pi model 4B. The complete measurement system includes protections, capacitor charging/discharging power electronics and current, voltage, irradiance and temperature sensors. Results, which include maximum power point, open circuit voltage, short circuit current and module efficiency, are displayed on an LCD touch display. Detailed description of the required software and the graphical user interface is also presented. This measurement system is very useful for testing photovoltaic installations, allowing an immediate verification whether the panels fulfill with the specifications and detection of possible failures.