scholarly journals Investigation of an embedded closed-loop stimulation current control principle based on the use of nonlinear ceramic capacitors

2021 ◽  
Vol 7 (2) ◽  
pp. 53-56
Author(s):  
Yves Olsommer ◽  
Frank R. Ihmig
Keyword(s):  
Dynamic Behavior ◽  
Closed Loop ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Materials ◽  
Current Control ◽  
Circuit Topology ◽  
Loop Control ◽  
Nonlinear Properties ◽  
Ceramic Capacitors ◽  
Stimulation Current

Abstract Over the years, a constant progress in the development of implantable medical devices (IMD’s) can be observed. On one hand, the advanced implantable electronics enable the implementation of numerous smart functionalities, on the other hand, the variety of electronic components including sensors and a bulky battery severely restrict their degree of miniaturization and reliability. To overcome this limitation, our approach is to realize smart functionalities in leadless and battery-free IMD’s emerging from frugal innovation by exploiting the intrinsic nonlinear properties of the components to be used anyway. The aim of this work is to deepen the understanding of the dynamic behavior of circuit topologies of nonlinear ferroelectric ceramic capacitors and to investigate their potential use for an embedded closed-loop control of the stimulation current. We characterized a selection of 40 commercial ceramic capacitors by measurement and simulation. The degree of nonlinearity resulting from a circuit topology consisting of one, two series and two parallel connected nonlinear capacitors was modeled and evaluated in Mathcad. We present a model with parameterized nonlinear capacitors to simulate the dynamic behavior of an inductively coupled implantable system. The stabilization and amplitude of the stimulation current is controlled by two features. These features are in turn controlled by the circuit topology and the degree of nonlinearity of the capacitors. We found that a high degree of nonlinearity allows the stimulation current to be stabilized within a reasonable range, but it makes the system more prone to instability. However, our model needs to include the dynamic behavior of ferroelectric materials used as dielectric in ceramic capacitors to extend the current investigations and to deepen the understanding of the physics behind the nonlinear properties of ferroelectric capacitors.

scholarly journals Experimental Characterization of Ferroelectric Capacitor Circuits for the Realization of Simply Designed Electroceuticals

2021 ◽  
Vol 2 (3) ◽  
pp. 299-311
Author(s):  
Yves Olsommer ◽  
Frank R. Ihmig
Keyword(s):  
Electronic Device ◽  
Linear Increase ◽  
Ferroelectric Materials ◽  
Unstable State ◽  
Battery Life ◽  
Induced Voltage ◽  
Therapeutic Success ◽  
Loop Control ◽  
Ceramic Capacitors ◽  
Stimulation Current

Currently, a large number of neurostimulators are commercially available for the treatment of drug-resistant diseases and as an alternative to pharmaceuticals. According to the current state of the art, such highly engineered electroceuticals require bulky battery units and necessitate the use of leads and extensions to connect the implantable electronic device to the stimulation electrodes. The battery life and the use of wired electrodes constrain the long-term use of such implantable systems. Furthermore, for therapeutic success and patient safety, it is of utmost importance to keep the stimulation current within a safe range. In this paper, we propose an implantable system design that consists of a low number of passive electronic components and does not require a battery. The stimulation parameters and power are transmitted inductively using an extracorporeal wearable transmitter at frequencies below 1 MHz. A simple circuit design approach is presented to achieve a closed-loop control of the stimulation current by exploiting the nonlinear properties of ferroelectric materials in ceramic capacitors. Twenty circuit topologies of series- and/or parallel-connected ceramic capacitors are investigated by measurement and are modeled in Mathcad. An approximately linear increase in the stimulation current, a stabilization of the stimulation current and an unstable state of the system were observed. In contrast to previous results, specific plateau ranges of the stimulation current can be set by the investigated circuit topologies. For further investigations, the consistency of the proposed model needs to be improved for higher induced voltage ranges.

Outlook of the Dynamic Behavior of Closed-Loop Control through Open-Loop Analysis for Intensified Separation Processes

2018 ◽  
Vol 57 (49) ◽  
pp. 16795-16808
Author(s):  
Julián Cabrera-Ruiz ◽  
César Ramírez-Márquez ◽  
Shinji Hasebe ◽  
Salvador Hernández ◽  
J. Rafael Alcántara Avila
Keyword(s):  
Dynamic Behavior ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
Loop Analysis ◽  
Separation Processes ◽  
Loop Control

scholarly journals Virtual Synchronous Generator Control of VSC-HVDC System Based on MMC of Hybrid Topology

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jie Wu ◽  
Chuanjiang Li
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Structural Characteristics ◽  
Synchronous Generator ◽  
Current Control ◽  
Current Loop ◽  
Power Module ◽  
Loop Control ◽  
Hybrid Topology ◽  
Virtual Synchronous Generator

For a VSC-HVDC transmission system based on a hybrid topology converter of full-bridge and half-bridge, a kind of virtual synchronous generator (VSG) control strategy which can be applied to modular multilevel converter (MMC) grid-connected structure was researched and proposed. First, based on the conventional VSG control strategy, the energy stored in the equivalent capacitor of MMC power module was used to imitate the rotor inertia of synchronous generator. The characteristics of generator can be simulated during transient frequency fluctuations and it can help relieve the power fluctuations. Secondly, with respect to the structural characteristics of the direct grid connection through the reactor on the AC side of the MMC, which is unlike the microgrid inverter, there are no additional filter capacitors. So, the existing commonly used VSG control strategy of the microgrid inverter and double-closed-loop structure composed of filter capacitor voltage and AC current cannot be directly applied. For this, a method where the given values of inner current loop are calculated by grid impedance matrix was used. So, a double-closed-loop control structure composed of a power outer loop based on VSG control and a current inner loop is obtained. It can effectively improve the current control capability during the transient process. Finally, a hybrid MMC simulation model was built based on PSCAD to verify the correctness and effectiveness of the proposed methods.

Modeling and Analysis of Arc Weld Inverter Based on Double Closed-Loop Control

2010 ◽  
Vol 36 ◽  
pp. 109-114
Author(s):  
Kuan Fang He ◽  
Ji Gang Wu ◽  
Xue Jun Li
Keyword(s):  
Power Supply ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Mathematic Model ◽  
Current Control ◽  
Soft Switching ◽  
Control Mode ◽  
Constant Current ◽  
Optimized Design ◽  
Loop Control

According to the soft-switching pulsed SAW (Submerged arc weld) weld power supply based on the double closed-loop constant current control mode, a small signal mathematic model of main circuit of soft-switching SAW inverter was established by applying the method of three-terminal switching device modeling method, and the mathematic model of double closed-loop phase-shift control system circuit was established by applying the method of state-space averaging method. Dynamic performance of the inverter was analyzed on base of the established mathematic model, and the tested wave of dynamic performance was shown by experimentation. Research and experimentation show that relation between structure of the power source circuit and dynamic performance of the controlling system can be announced by the established mathematic model, which provides development of power supply and optimized design of controlling parameter with theoretical guidance.

scholarly journals Design and Simulation of a Dual Conversion Transformerless Online and Line-Interactive UPS

2019 ◽  
Vol 67 (2) ◽  
pp. 79-84
Author(s):  
Md Mahmud Ul Tarik Chowdhury ◽  
Md Saleh Ebn Sharif ◽  
Fakir Mashuque Alamgir
Keyword(s):  
State Space ◽  
Dynamic Behavior ◽  
System Performance ◽  
Closed Loop ◽  
State Of Charge ◽  
Closed Loop Control ◽  
Loop Control ◽  
Battery Charge ◽  
System Components ◽  
Charge Management

In this paper, a dual-conversion online static UPS and Line-Interactive UPS system was modeled and simulated using PSIM software. The components of the proposed design were specified based on pre-defined constrains, and the dynamic behavior of the system was modeled through state-space equations. With the system components characterized, a suitable controller was developed for closed-loop control of the buck and boost circuits. A battery charge management controller was also developed to ensure the robustness of the design. Overall system performance was analyzed under varying load and line conditions. Conversion bypass switching was simulated and the overall system performance was analyzed while observing the state of charge – SOC behavior of the battery. Dhaka Univ. J. Sci. 67(2): 79-84, 2019 (July)

scholarly journals Modeling the Nonlinear Properties of Ferroelectric Materials in Ceramic Capacitors for the Implementation of Sensor Functionalities in Implantable Electronics

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 61
Author(s):  
Yves Olsommer ◽  
Frank R. Ihmig ◽  
Carsten Müller
Keyword(s):  
Solution Concept ◽  
Ferroelectric Materials ◽  
Nonlinear Characteristics ◽  
Differentiation Formula ◽  
Nonlinear Properties ◽  
Ceramic Capacitors ◽  
Implantable Electronics ◽  
Adaptive Step ◽  
The Given ◽  
Functional Electrostimulation

For several years, the requirements on miniaturization of electronic implants with application in functional electrostimulation have been increasing, while functionality and reliability should not be impaired. One solution concept is to use neither active electronic components nor sensors or batteries. Instead, the functionalities are ensured by the use of intrinsic nonlinear properties of the already used components and energy is transferred by inductive coupling. In this paper, ceramic capacitors are investigated as a first step towards exploiting the nonlinear characteristics of ferroelectric materials. The ceramic capacitors are characterized by simulation and measurements. The modeling is carried out in Mathcad Prime 3.1 and ANSYS 2019 R2 Simplorer and different solvers are compared for exemplary calculations. Finally, a measurement setup is realized to validate the models. Calculations show that the trapezoid method with a number of 500 k points in the given solution interval is best suited for ANSYS. In Mathcad, the Adams, Bulirsch–Stoer, Backward Differentiation Formula, Radau5, and fourth order Runge–Kutta methods with an adaptive step width and a resolution of 50 k points are the most suitable. The nonlinear properties of ferroelectric materials in ceramic capacitors modeled with these methods using ANSYS and Mathcad show small and equal deviation from the measurements.

Study on SVG Simulation with the Voltage and Current Dual Closed-Loop PWM Control Strategy

2013 ◽  
Vol 732-733 ◽  
pp. 1265-1270
Author(s):  
Xin Chun Shi ◽  
Wei Zhang ◽  
Pei Ran Liu
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Dynamic Performance ◽  
Current Control ◽  
Closed Loop Control ◽  
Pwm Control ◽  
Basic Principles ◽  
Loop Control ◽  
Direct Current Control ◽  
Coordinate Process

This paper first introduced the SVG main circuit and the basic principles of SVG, then finished SVG modeling in dq coordinate process. Then an SVG direct current control method was proposed as well. Considering stability requirement to the DC side voltage, the paper designed voltage and current dual closed-loop PWM control system. Finally, SVG system was simulated using the Matlab/simulink. Results show that SVG has a good dynamic performance, verifying the correctness and validity of the dual closed-loop control.

The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück
Keyword(s):  
Empirical Research ◽  
Visual Feedback ◽  
Closed Loop ◽  
Motor Planning ◽  
Visual Input ◽  
Closed Loop Control ◽  
Loop Control ◽  
Feedback Type ◽  
Effective Use ◽  
The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

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