RESUMO
Recently, a novel method for the growth inhibition of malaria parasites using microwaves was proposed. However, the apparatuses used to demonstrate this method are high-cost and immovable, hindering the progression in this field of research, which is still in its early stages. This paper presents the redesign, construction, and validation of an equivalent system, converting it into a portable and low-cost system, capable of replacing the existing one. The proposed system is mainly composed of an RF generator (MAX2870), an RF amplifier (SKYWORKS 66292-11) and a graphical user interface. Likewise, the RF applicator proposed by the original study was redesigned, resulting in a five-fold improvement in return loss. The obtained results indicate that the proposed system achieves 90% parasite growth inhibition, matching the performance of its counterpart at less than 1% of its cost. These results represent a breakthrough for the creation of smaller, enhanced devices that open new possibilities for an alternative treatment to combat this devastating disease.
RESUMO
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.
RESUMO
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.