Minimally invasive insertion of thecoperitoneal shunts using ventriculoscope

Background: Thecoperitoneal shunt insertion is an effective widely used procedure for treatment of idiopathic intracranial hypertension. Laparoscopic insertion of the peritoneal end minimizes extraperitoneal insertion, shunt migration, and shunt obstruction. However, this needs availability of laparoscopy sets and experienced laparoscopic surgeon. The aim of this study is to evaluate feasibility, safety and effectiveness of minimally invasive thecoperitoneal shunt insertion using ventriculoscope. Methods: Prospective study of 15 patients with IIH operated for minimally invasive thecoperitoneal shunt insertion using ventriculoscope. Operative time, intraoperative and post-operative complication, and clinical outcome were recorded. Results: All patients were females with mean age 27.2 years. The mean body mass index was 44.4. Headache and papilledema were present in all cases with mean CSF manometry 41.7 cm. Mean operative time was 48.9 min. Clinical improvement was achieved in all patients except one patient who developed shunt infection and meningitis. Conclusion: Minimally invasive thecoperitoneal shunt insertion using ventriculoscope is easy and safe. It minimizes complication of shunt obstruction, migration and extraperitoneal insertion in obese patients

Enhanced Virtual Inertia Control for Microgrids with High-Penetration Renewables Based on Whale Optimization

High penetration of renewable energy sources into isolated microgrids (µGs) is considered a critical challenge, as µGs’ operation at low inertia results in frequency stability problems. To solve this challenge, virtual inertia control based on an energy storage system is applied to enhance the inertia and damping properties of the µG. On the other hand, utilization of a phase-locked loop (PLL) is indispensable for measuring system frequency; however, its dynamics, such as measurement delay and noise generation, cause extra deterioration of frequency stability. In this paper, to improve µG frequency stability and minimize the impact of PLL dynamics, a new optimal frequency control technique is proposed. A whale optimization algorithm is used to enhance the virtual inertia control loop by optimizing the parameters of the virtual inertia controller with consideration of PLL dynamics and the uncertainties of system inertia. The proposed controller has been validated through comparisons with an optimized virtual inertia PI controller which is tuned utilizing MATLAB internal model control methodology and with H∞-based virtual inertia control. The results show the effectiveness of the proposed controller against different operating conditions and system disturbances and uncertainties

Implementation of New Optimal Control Methodology of Quazi Z-Source Inverter Based on MPC

Model predictive control (MPC) is a well-known control methodology in power electronics systems, due to its ability to deal with the system’s nonlinearities and superior dynamic response. MPC is able to handle multiple variables by adjusting the cost function, but this leads to high computational costs, especially for systems having a big number of switches. This problem increases when not only performance efficiency is required but also minimizing the power losses of these systems. In this paper, a modified MPC algorithm is presented for controlling a three-phase quasi Z-source inverter (qZSI), i.e., providing switching states to be applied for qZSI control, so that, within less computation time, total harmonic distortion (THD) of the output currents is maintained at the minimum level with concurrent minimization of inverter switch power losses. The computational burden is reduced by using calculation loop optimization, reducing the number of switching states in the loop and unrolling the calculation loop. To highlight the effectiveness of the proposed control methodology, a numerical simulation was carried out using MATLAB software. The obtained results have been discussed and compared with those of a recent previous study