Electroporation pulse generator for biomedical applications with improved output voltage ripple and reduced bus capacitor

Electroporation is a promising cancer treatment based on applying short electric field pulses. In this context, highly versatile pulse generators are required to generate high-voltage low-ripple pulses in the µs range. In the past, several multi-level converters have been proposed to achieve this aim. Achieving constant output voltage and, consequently, electric field is essential to obtain predictable treatments and minimize the risks of tumor relapse. However, significant bus capacitance is required to achieve the required performance, leading to bulky equipment with serious safety implications due to the stored energy. In this letter, a high-performance pulse generator for electroporation is proposed that takes advantage of a multi-level structure with linear voltage regulation to achieve the desired performance with reduced bus capacitance. The proposed converter has been designed and tested experimentally during both laboratory and operation room treatments

GaN-based matrix resonant power converter for domestic induction heating

Flexible-surface induction cooktops must operate with a variety of induction heating loads with different behavior and power setpoints to be heated simultaneously. In this context, multi-output inverter topologies aim at achieving independent power management while featuring low power-device count and high power density. However, they suffer from limitations when applying classical modulation strategies to ensure soft switching, which is required to reduce transistor losses and achieve efficient operation. In this scenario, wide band-gap devices reduce switching losses, opening a new paradigm in power conversion where soft switching is not mandatory in order to achieve high efficiency. This paper proposes an implementation of a multi-output resonant inverter based on GaN HEMTs and evaluates various modulation strategies in terms of efficiency under different switching modes. The proposed approach is designed and experimentally validated by means of a 2-coil 2000 W prototype implementation

Analysis and design of tubular coils for wireless inductive power transfer systems

We evaluate copper tubes as alternative of litz wire for planar coils of inductive power transfer (IPT) systems. For this purpose, a design methodology focused on maximizing the product of the magnetic coupling and the quality factor is proposed. The methodology is based on a combination of FEA simulations and analytical calculations of the skin and proximity losses in the tube. Analytical calculations are based on solutions of Maxwell''s equations for a tubular geometry. These solutions are oriented to extract both skin and proximity losses in the tube. Performance of a prototype of 1.5 kW is evaluated and compared with a conventional litz-wire implementation

A flexible cooking zone composed of partially overlapped inductors

Domestic induction cookers are evolving from fixed cooking areas to flexible surfaces in such a way that the pot can be placed at any position. This implies the use of a larger number of reduced-sized inductors, which present a lower efficiency. As a solution to increase the efficiency while maintaining the flexibility, we propose the use of partially overlapped inductors of a larger size. This concept is currently in use in wireless power transfer systems, where the transmitter arrangement consists of several overlapped coils. The aim of this paper is to evaluate this concept applied to domestic induction heating appliances, with special emphasis in analyzing the effects of introducing the multicoil system with dissipative media. Moreover, the losses in the winding will be studied in detail. The system will be prototyped and tested, delivering up to 3.7 kW

Self-adaptive overtemperature protection materials for safety-centric domestic induction heating applications

Security aspects in the household sphere have become a major concern in modern societies. In particular, regardless of the technology used, users increasingly appreciate a protection system to prevent material damage in the case of human errors or distractions during the cooking process. This paper presents a sensorless method for detecting and limiting overtemperature, unique to induction cooktops, based on their specific features, such as automatic pot detection and load power factor estimation. The protection system exploits the change in the load material properties at certain temperatures, the effect of which may be enhanced by arranging a multilayer structure comprising a low Curie temperature alloy and an aluminum layer. The proposed multilayer load exhibits two differentiated states: a normal state, where the cookware is efficiently heated, and a protection state, above the safety temperature, where the power factor abruptly decreases, limiting the overheating and making the state easily detectable by the cooktop. This method of overtemperature self-protection uses the electronics of conventional induction cooktops; therefore, no other sensors or systems are required, reducing its complexity and costs. Simulation and experimental results are provided for several cookware designs, thereby proving the feasibility of this proposal

Modelado numérico de pérdidas en conductores de sección rectangular mediante análisis por elementos finitos

En esta ponencia, se presenta un método para calcular las pérdidas en alterna (incluyendoefecto skin y proximidad) en dispositivos magnéticos planares con sección de conducciónrectangular. Se desarrolla un modelado de pérdidas similar al empleado con conductores desección circular para los conductores anteriormente mencionados. El objetivo es obtener unproceso de diseño adecuado, especialmente para los dispositivos magnéticos implementadosen placa de circuito impreso (PCB). Básicamente, el modelado de pérdidas está basado en lasuperposición de las pérdidas en el conductor (pérdidas de conducción y de proximidad), ytambién en una descomposición ortogonal del campo bajo el que se encuentran losconductores. El número de funciones necesarias para calcular las pérdidas de proximidad sereduce a una, tal y como ocurre en los conductores circulares. Esta función, junto con lafunción que describe las pérdidas de conducción, ambas contienen las dependenciasgeométricas y frecuenciales, son calculadas y tabuladas mediante un Análisis por ElementosFinitos (FEA). El campo magnético se calcula mediante una simulación magnetostática basadaen FEA. De esta forma las pérdidas son obtenidas con una reducción del tiempo de cálculoconsiderable. Finalmente, se han caracterizado varios prototipos para verificar el modelado depérdidas

Robot-Assisted Versus Laparoscopic Distal Pancreatectomy in Patients with Resectable Pancreatic Cancer: An International, Retrospective, Cohort Study

Background: Robot-assisted distal pancreatectomy (RDP) is increasingly used as an alternative to laparoscopic distal pancreatectomy (LDP) in patients with resectable pancreatic cancer but comparative multicenter studies confirming the safety and efficacy of RDP are lacking. Methods: An international, multicenter, retrospective, cohort study, including consecutive patients undergoing RDP and LDP for resectable pancreatic cancer in 33 experienced centers from 11 countries (2010–2019). The primary outcome was R0-resection. Secondary outcomes included lymph node yield, major complications, conversion rate, and overall survival. Results: In total, 542 patients after minimally invasive distal pancreatectomy were included: 103 RDP (19%) and 439 LDP (81%). The R0-resection rate was comparable (75.7% RDP vs. 69.3% LDP, p = 0.404). RDP was associated with longer operative time (290 vs. 240 min, p < 0.001), more vascular resections (7.6% vs. 2.7%, p = 0.030), lower conversion rate (4.9% vs. 17.3%, p = 0.001), more major complications (26.2% vs. 16.3%, p = 0.019), improved lymph node yield (18 vs. 16, p = 0.021), and longer hospital stay (10 vs. 8 days, p = 0.001). The 90-day mortality (1.9% vs. 0.7%, p = 0.268) and overall survival (median 28 vs. 31 months, p = 0.599) did not differ significantly between RDP and LDP, respectively. Conclusions: In selected patients with resectable pancreatic cancer, RDP and LDP provide a comparable R0-resection rate and overall survival in experienced centers. Although the lymph node yield and conversion rate appeared favorable after RDP, LDP was associated with shorter operating time, less major complications, and shorter hospital stay. The specific benefits associated with each approach should be confirmed by multicenter, randomized trials

Induction Heating Technology and Its Applications: Past Developments, Current Technology, and Future Challenges

International audienceInduction heating technology is nowadays the heating technology of choice in many industrial, domestic, and medical applications due to its advantages regarding efficiency, fast heating, safety, cleanness, and accurate control. Advances in key technologies, i.e. power electronics, control techniques, and magnetic component design, have allowed the development of highly reliable and cost-effective systems, making this technology readily available and ubiquitous. This papers reviews induction heating technology summarizing the main milestones in its development, and analyzing the current state-of-art of induction heating systems in industrial, domestic and medical applications, paying special attention to the main technologies involved. Finally, an overview of future research trends and challenges is given, highlighting the promising future of induction heating technology

An Inter-Disciplinary Approach to Teaching Biomedical Electronics with an Electroporation-Applied Example

none6sinoneSarnago, H.;Sieni, E.; Lopez-Alonso, B.; Carretero, C.; Burdio, J.M.; Lucia, O.Sarnago, H.; Sieni, E.; Lopez-Alonso, B.; Carretero, C.; Burdio, J. M.; Lucia, O

Laparoscopic partial splenectomy for giant cyst using a radiofrequency-assisted device: a case report

Background: Although radiofrequency-assisted devices have sometimes been used in partial splenectomy, this is not a common technique. This report describes the first case of laparoscopic partial splenectomy using an RF-assisted device (Coolinside) which allows both coagulation and transection of the parenchyma and eventually the protective coagulation of the remnant side. Case presentation: A 27-year-old woman was found to have a giant hydatic cyst measuring 12.0 × 14.0 × 16.6 cm that mainly occupied the lower pole of the spleen and retroperitoneal space. The patient underwent a laparoscopic partial splenectomy using an RF-based device designed to accomplish both the coagulation and dissection of the splenic tissue. The estimated blood loss was less than 200 mL. Conclusions: Even though RF ablation has traditionally been used for hepatic parenchymal transection, it seems equally suited to partial splenectomy. This device seems to provide good results, minimizing blood loss during partial splenectomy; however, randomized trials will be necessary to see if the results are superior to those of other techniques.This work was partially supported by the Spanish “Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad” under Grant TEC2014-52383-C3-R (TEC2014-52383-C3-1-R and TEC2014-52383-C3-3-R)