A New Dual Polarity Direct AC-AC Voltage Regulator Ensuring Voltage Step-Up and Step-Down Capabilities

The problem of voltage sag and swell is one of the major reasons for low-quality power in the distribution system. Normally, it results from the system’s faults, including line-to-ground and line-to-line, non-linear characteristics of loads and sources. Its effect is very serious for the critical loads as their performance is very sensitive to the variation in voltage. The stabilization of voltage is a mandatory requirement in such a situation. The correction of such problems requires the addition and subtraction of the voltage once the line voltage is decreased and increased. This behavior of the correcting voltage is ensured by the use of voltage controllers that can convert a constant input voltage into a non-inverted and inverted variable form. Their voltage gains depend on the depth level of the problem. The voltage buck and boost capabilities of the AC voltage stabilizers can tackle the problems having any depth level. The smartness of such a system depends on the number of electronic devices as they are the key elements in the power conversion system. Therefore, this research proposes a new AC voltage controller with fewer solid-state devices. Its overall impact is low volume and cost. The validation of the introduced approach is ensured with the help of simulation modeling and results gained from the practical setup.

Dynamic equivalence of doubly-fed wind turbines based on parameter identification and optimization

The dynamic equivalence and modeling of large-scale wind farms is the basis for studying the problem of multi-temporal and spatial scale wind farms grid connection, and the establishment of a high-precision equivalence model is a key issue among them. This paper takes doubly-fed wind turbines as the research object. Aiming at the problem of large dynamic errors in direct aggregation of equivalents into a single unit, an equivalent model combined with particle swarm optimization algorithm is established to improve the accuracy of dynamic equivalents. The electrical parameters, reactive power reference values, active power controller parameters, and active DC voltage controller parameters are optimized using particle swarm optimization. The research results show that the equivalent model after optimizing the parameters of the active power and DC bus voltage controller is the closest to the detailed model in describing the dynamic characteristics of multiple machines.

A Novel H∞ Robust Control Strategy for Voltage Source Inverter in Microgrid

The voltage control performance of the voltage source inverter (VSI) in a microgrid may change under different load conditions. However, in the case of traditional control strategies, the robustness of VSI is insufficient. In response to the above problems, a novel robust control scheme for VSI in the microgrid based on H∞ hybrid sensitivity is proposed in this study. The grid-side interference during the VSI operation is taken as the variable, and the sensitivity function is designed to build a H∞ robust voltage controller for VSI. In addition, an adaptive virtual impedance group is designed to further improve the voltage control robustness under a variety of operation conditions. Finally, comparative simulation experiments are carried out to verify the anti-interference ability of the proposed control strategy under different working conditions.

Wireless Charger for Artificial Pacemaker

The vast majority of the modernized implantable devices and Bio-sensors are set inside a patient’s body. To overcome this constraint, in this paper we have designed a rechargeable battery with wireless power transfer technique. The transdermal power transfer for the Pacemaker which is placed inside the heart should be possible by the concept of mutual inductance. The receiver loop ought to be situated inside the body and the transmitter curl ought to be situated outside of the body. The voltage controller will give or manage the necessary yield (output) voltage. The experiments were conducted on wireless charging through pork tissues reveal that from a 3.919-mw power source, 3.072-mw power can be received at 300kHz, reaching a high wireless power transfer efficiency of 78.4%, showing that the charging is very fast. We have also connected a Bluetooth Module to the Atmega328 microcontroller. This Bluetooth technology is used in the Android mobile application to notice the charging levels of the pacemaker. This Inductive power transfer technique takes out the danger of contamination which is brought about by the medical procedure.