Experimental data validating the optimization of a wireless power transfer prototype employing a novel phase shift measurement system and frequency control.

Resonant wireless power transfer (WPT) systems have been evolving and improving their designs over the last few years, looking to efficiently charge electric vehicles, cellphones, and biomedical devices. In this article, we present to the scientific community the data obtained from the optimization of a resonant WPT prototype, operating at different vertical misalignments and load conditions, known to have an impact on the behavior of these type of systems. To maximize the power transferred to the load, we developed a proportional-integral frequency control algorithm that employs the phase-shift between the voltage and current waveforms in the transmitting antenna (resonance indicator) as a setpoint. Data on the performance and control optimization process of the prototype during laboratory tests were acquired using a LabVIEW interface, which was designed to capture information such as the evolution of the frequency, the phase-shift, and the load voltage, from multiple devices (a microcontroller, an oscilloscope, a digital multimeter, and a controllable power supply). The data were organized and presented in tables and graphs using MATLAB. The importance of the dataset relies on the opportunity to utilize the information as a basis for the improvement of the associated electronics by using different transmission topologies, higher speed components, new-generation microcontrollers, and to modelling novel intelligent control algorithms, such as adaptative neuro-fuzzy inference systems.

Low-cost, microcontroller-based phase shift measurement system for a wireless power transfer prototype.

Seeking to characterize and mitigate the adverse effects of misalignment in WPT applications, we present the design and construction of a low-cost wireless charger prototype and a novel phase-shift measurement system. The first is built using a half-bridge inverter and antennas with series-series compensation, while a microcontroller (Teensy 4.1) supplies high-frequency PWM signals. The measurement system comprises high-speed operational amplifiers and an exclusive OR gate. A resistor was used as load. On the other hand, the maximum power transfer efficiency occurs at the resonance frequency, nevertheless, this depends physically on the geometry of the coupling system. Using a 3D-printed displacement system, we created controlled vertical misalignments between the coils, thereby obtaining variations in the resonance frequency of the system and consequently, producing a proportional phase shift between the voltage and current waves of the transmitting antenna. As the experimental results demonstrate, the measurement system can process this high-frequency signal for the phase shift estimation and subsequently use it as a control variable in a proportional-integral controller, which adjusts the operation frequency of the system and brings it back to optimal conditions. This precise yet inexpensive implementation could find its application in EVs and biomedical devices' efficient wireless chargers.

Low-cost, rapidly deployable emergency mechanical ventilators during the COVID-19 pandemic in a developing country: Comparing development feasibility between bag-valve and positive airway pressure designs.

The COVID-19 pandemic disrupted the world by interrupting most supply chains, including that of the medical supply industry. The threat imposed by export restriction measures and the limitation in the availability of mechanical ventilators posed a higher risk for smaller, developing countries, used to importing most of their technologies. To actively respond to the possible device shortage, the initiative "Ventilators for Panama" was established and was able to develop two different, non-competing, open-source hardware mechanical ventilator models for emergency use in case of shortages: one based on a bag-valve design and another based on positive airway pressure. The aim of this article is to compare both devices in terms of feasibility and functionality. Results from the functional testing show that both devices perform within specification, as the error percentage is lower than 5% for the desired pressure values and a standard deviation of less than 0.5 for all cases.Clinical Relevance- This study shows the feasibility of quickly deploying two different mechanical ventilator designs for emergency use and their effectiveness.