The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Fernando Seoane - One of the best experts on this subject based on the ideXlab platform.

  • simple voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy circuit dependences and limitations
    Measurement Science and Technology, 2011
    Co-Authors: Fernando Seoane, Raul Macias, Ramon Bragos, Kaj Lindecrantz
    Abstract:

    In this work, the single Op-Amp with load-in-the-loop topology as a Current Source is revisited. This circuit topology was already used as a voltage-Controlled Current Source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the Currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working Current Source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a Current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with Current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the Source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient Current Source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a Current Source in EBI at this frequency.

  • performance of the load in the loop single op amp voltage Controlled Current Source from the op amp parameters
    International Conference Electrical Bioimpedance, 2010
    Co-Authors: Fernando Seoane, Raul Macias, Ramon Bragos
    Abstract:

    In recent years, Electrical Bioimpedance (EBI) methods have gained importance. These methods are often based on obtaining impedance spectrum in the range of β-dispersion, i.e. from a few kHz up to some MHz. To measure EBI a constant Current is often injected and the voltage across the tissue under study is recorded. Due to the performance of the Current Source influences the performance of the entire system, in terms of frequency range, several designs have been implemented and studied. In this paper the basic structure of a Voltage-Controlled Current Source based on a single Op-Amp in inverter configuration with a floating load, known as load-in-the-loop Current Source, is revisited and studied deeply. We focus on the dependence of the output impedance with the circuit parameters, i.e. the feedback resistor and the inverter-input resistor, and the Op-Amp main parameters, i.e. open loop gain, CMRR and input impedance. After obtaining the experimental results, using modern Op-Amps, and comparing to the theoretical and simulated ones, they confirm the design under study can be a good solution for multi-frequency wideband EBI applications because of higher values of the output impedance than 100kΩ at 1MHz are obtained. Furthermore, an enhancement of the basic design, using a Current conveyor as a first stage, is proposed, studied and implemented.

  • Enhancement of a voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy
    2006
    Co-Authors: Fernando Seoane, Kaj Lindecrantz
    Abstract:

    Enhancement of a voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy

Kaj Lindecrantz - One of the best experts on this subject based on the ideXlab platform.

  • simple voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy circuit dependences and limitations
    Measurement Science and Technology, 2011
    Co-Authors: Fernando Seoane, Raul Macias, Ramon Bragos, Kaj Lindecrantz
    Abstract:

    In this work, the single Op-Amp with load-in-the-loop topology as a Current Source is revisited. This circuit topology was already used as a voltage-Controlled Current Source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the Currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working Current Source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a Current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with Current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the Source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient Current Source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a Current Source in EBI at this frequency.

  • Enhancement of a voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy
    2006
    Co-Authors: Fernando Seoane, Kaj Lindecrantz
    Abstract:

    Enhancement of a voltage Controlled Current Source for wideband electrical bioimpedance spectroscopy

H. Tuusa - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Vector Controlled Current Source Shunt Active Power Filter with Reduced Component Voltage Stresses
    2007 IEEE Power Electronics Specialists Conference, 2007
    Co-Authors: P. Parkatti, M. Salo, H. Tuusa
    Abstract:

    Voltage stresses and power losses are a problem in active power filters. In this paper a novel topology for reducing component voltage strains and power losses in a Current Source shunt active power filter (CSAPF) is presented. The voltage stresses are compared with a conventional CSAPF and results are encouraging.

  • A novel vector Controlled Current Source shunt active power filter and its comparison with a traditional topology
    2007 European Conference on Power Electronics and Applications, 2007
    Co-Authors: P. Parkatti, M. Salo, H. Tuusa
    Abstract:

    Power losses and voltage stresses are a problem in active power filters. This paper presents a novel topology for reducing component voltage stresses and power losses in a Current Source shunt active power filter (CSAPF). The compensation provided by the proposed topology is compared with that of a conventional CSAPF topology and simulation results are presented. The operation of the simulation model was also verified with prototype measurements.

  • A vector Controlled Current-Source PWM rectifier with a novel Current damping method
    IEEE Transactions on Power Electronics, 2000
    Co-Authors: M. Salo, H. Tuusa
    Abstract:

    Three-phase Current-type pulse width modulation (PWM) rectifiers are becoming increasingly popular as the front-end converter unit in power electronic systems due to tighter electromagnetic compatibility (EMC) regulations. In this paper the control of the Current Source PWM rectifier in the synchronously rotating reference frame is discussed. A control system is presented in which the active and reactive power are independently Controlled with real and imaginary axis components of the supply Current vector. A new damping method for supply Current oscillations is introduced. The method operates in an open-loop manner and is very suitable for microcontroller implementation since the calculation power demand is low. Furthermore, it is shown that in the synchronously rotating coordinates, where the sinusoidal variables appear as DC quantities, the compensation of the reactive power drawn by the supply filter can be done very easily. The proposed control methods are realized using a single-chip Motorola MC68HC916Y1 microcontroller. The experimental tests show excellent performance in both steady state and transient conditions.

P. Ziogas - One of the best experts on this subject based on the ideXlab platform.

  • Input characteristics of variable modulation index Controlled Current Source inverters
    IEEE Transactions on Industrial Electronics, 1994
    Co-Authors: G. Moschopoulos, G. Joos, P. Ziogas
    Abstract:

    Standard PWM Current Source inverters (CSIs) usually operate at fixed modulation index. The proposed modified Current Source inverter (MCSI) can operate with most pulse width modulation (PWM) techniques and with a variable modulation index, since the DC link inductor Current freewheels on itself and not through the CSI. The use of variable modulation index control results in faster response times with no penalty on input power factor as compared to other variable modulation index schemes. This paper confirms this by investigating the input characteristics of the MCSI as seen from the AC mains. The quality of the input AC line Currents is examined, and a design procedure for the input filters is given. Power factor and efficiency are discussed. Results are compared to those of other Current Source inverter topologies. Experimental results obtained from a 5 kVA converter confirm the theoretical considerations.

  • Voltage Controlled Current Source inverters
    Proceedings of the 1992 International Conference on Industrial Electronics Control Instrumentation and Automation, 1992
    Co-Authors: J. Espinoza, G. Joos, P. Ziogas
    Abstract:

    The authors present a fully functional voltage Controlled Current Source inverter (VC-CSI) three-phase inverter that can closely track a given voltage reference signal and also provide various performance improvements. The adaptive SPWM control method has been used to force the output voltage to track the respective sinusoidal reference signals. The combination yields a general-purpose three-phase balanced voltage supply with precise frequency and voltage amplitude control. Moreover, it has the inherent regeneration and short circuit protection features associated with Current Source inverters. Key analysis/design results and performance features are verified on a 2 kVA experimental inverter-load prototype system.

M. Salo - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Vector Controlled Current Source Shunt Active Power Filter with Reduced Component Voltage Stresses
    2007 IEEE Power Electronics Specialists Conference, 2007
    Co-Authors: P. Parkatti, M. Salo, H. Tuusa
    Abstract:

    Voltage stresses and power losses are a problem in active power filters. In this paper a novel topology for reducing component voltage strains and power losses in a Current Source shunt active power filter (CSAPF) is presented. The voltage stresses are compared with a conventional CSAPF and results are encouraging.

  • A novel vector Controlled Current Source shunt active power filter and its comparison with a traditional topology
    2007 European Conference on Power Electronics and Applications, 2007
    Co-Authors: P. Parkatti, M. Salo, H. Tuusa
    Abstract:

    Power losses and voltage stresses are a problem in active power filters. This paper presents a novel topology for reducing component voltage stresses and power losses in a Current Source shunt active power filter (CSAPF). The compensation provided by the proposed topology is compared with that of a conventional CSAPF topology and simulation results are presented. The operation of the simulation model was also verified with prototype measurements.

  • A vector Controlled Current-Source PWM rectifier with a novel Current damping method
    IEEE Transactions on Power Electronics, 2000
    Co-Authors: M. Salo, H. Tuusa
    Abstract:

    Three-phase Current-type pulse width modulation (PWM) rectifiers are becoming increasingly popular as the front-end converter unit in power electronic systems due to tighter electromagnetic compatibility (EMC) regulations. In this paper the control of the Current Source PWM rectifier in the synchronously rotating reference frame is discussed. A control system is presented in which the active and reactive power are independently Controlled with real and imaginary axis components of the supply Current vector. A new damping method for supply Current oscillations is introduced. The method operates in an open-loop manner and is very suitable for microcontroller implementation since the calculation power demand is low. Furthermore, it is shown that in the synchronously rotating coordinates, where the sinusoidal variables appear as DC quantities, the compensation of the reactive power drawn by the supply filter can be done very easily. The proposed control methods are realized using a single-chip Motorola MC68HC916Y1 microcontroller. The experimental tests show excellent performance in both steady state and transient conditions.