Now showing 1 - 10 of 39
  • Publication
    Wideband electrostatic Vibration Energy Harvester (e-VEH) having a low start-up voltage employing a high-voltage integrated interface
    This paper reports on an electrostatic Vibration Energy Harvester (e-VEH) system, for which the energy conversion process is initiated with a low bias voltage and is compatible with wideband stochastic external vibrations. The system employs the auto-synchronous conditioning circuit topology with the use of a novel dedicated integrated low-power highvoltage switch that is needed to connect the charge pump and flyback - two main parts of the used conditioning circuit. The proposed switch is designed and implemented in AMS035HV CMOS technology. Thanks to the proposed switch device, which is driven with a low-voltage ground-referenced logic, the e-VEH system may operate within a large voltage range, from a pre-charge low voltage up to several tens volts. With such a high-voltage e-VEH operation, it is possible to obtain a strong mechanical coupling and a high rate of vibration energy conversion. The used transducer/resonator device is fabricated with a batch-processed MEMS technology. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110-170 Hz, up to 0.75 μW of net electrical power has been harvested with our system. This work presents an important milestone in the challenge of designing a fully integrated smart conditioning interface for the capacitive e-VEHs.
    Scopus© Citations 17  527
  • Publication
    Semi-Analytical Method for the Extraction of the System Parameters in Application to Kinetic Energy Harvesters
    In this paper, we propose a technique to extract system parameters of nonlinear MEMS devices using a combination of model reduction and nonlinear optimization. The model is tested on a MEMS energy harvesting device employing magnetic actuation and piezoelectric energy conversion.
      296
  • Publication
    Dielectric charge control in electrostatic MEMS positioners / varactors
    A new dynamical closed-loop method is proposed to control dielectric charging in capacitive MEMS positioners/ varactors for enhanced reliability and robustness. Instead of adjusting the magnitude of the control voltage to compensate the drift caused by the dielectric charge, the method uses a feedback loop to maintain it at a desired level: the device capacitance is periodically sampled and bipolar pulses of constant magnitude are applied. Specific models describing the dynamics of charge and a control map are introduced. Validation of the proposed method is accomplished both through discrete-time simulations and with experiments using MEMS devices that suffer from dielectric charging.
      692Scopus© Citations 23
  • Publication
    Excitation of multiple spatial modes of a MEMS cantilever in the pulsed digital oscillator
    The aim of this paper is to apply an approach that will allow us to consider different mechanical modes of a MEMS cantilever in the form of separate mass-spring-damper equations with the appropriate form of an external driving. In the paper, we focus on a specific MEMS cantilever and use a Pulsed Digital Oscillator (PDO) to keep self-sustained oscillations of the mechanical structure. By applying the order-reduction procedure to a partial differential equation that describes the transversal deflections, we obtain a system of coupled ordinary differential equations that describes the excitation of multiple spatial modes. On the basis of these ordinary differential equations, we formulate a set of iterative maps to describe the evolution of the modes between two sampling events. The numerical simulations we present are focused on the most common case when the first two mechanical modes are taken into consideration
      342
  • Publication
    Capacitive Energy Conversion with Circuits Implementing a Rectangular Charge-Voltage Cycle Part 1: Analysis of the Electrical Domain
    Capacitive kinetic energy harvesters (KEH) employ conditioning circuits which achieve a dynamic biasing of the transducer's variable capacitor. This paper, composed of two articles Part 1 and Part 2, proposes a unified theory describing electrical and electromechanical properties of an important and wide class of conditioning circuits: those implementing a rectangular charge-voltage cycle. The article Part 1 introduces a basic configuration of conditioning circuit implementing an ideal rectangular QV cycle, and discusses its known practical implementations: the Roundy charge pump with different flyback mechanisms, and configurations based on the Bennet's doubler. In Part 1, the analysis is done in the electrical domain, without accounting for electromechanical coupling, while in Part 2, the full electromechanical system is analyzed. An optimization approach common to all configurations is proposed. A comparison is made between different topologies and operation modes, based on the maximal energy converted in one cycle under similar electrical and mechanical conditions. The last section discusses practical implementation of circuits with smart and adaptive behavior, and presents experimental results obtained with state-of-the art MEMS capacitive KEH devices.
      486Scopus© Citations 39
  • Publication
    Steady-State Oscillations in Resonant Electrostatic Vibration Energy Harvesters
    In this paper, we present a formal analysis and description of the steady-state behavior of an electrostatic vibration energy harvester operating in constant-charge mode and using different types of electromechanical transducers. The method predicts parameter values required to start oscillations, allows a study of the dynamics of the transient process, and provides a rigorous description of the system, necessary for further investigation of the related nonlinear phenomena and for the optimisation of converted power. We show how the system can be presented as a nonlinear oscillator and be analysed by the multiple scales method, a type of perturbation technique. We analyse two the most common cases of the transducer geometry and find the amplitude and the phase of steady-state oscillations as functions of parameters. The analytical predictions are shown to be in good agreement with the results obtained by behavioural modeling.
    Scopus© Citations 32  711
  • Publication
    Complete electromechanical analysis of electrostatic kinetic energy harvesters biased with a continuous conditioning circuit
    This paper presents a comprehensive electromechanical study of an electrostatic kinetic energy harvester (eKEH) biased with a continuous voltage. This simple circuit refers to any capacitive transducer with an in-built voltage source, such as an electret, or DC biased transducer connected directly to a resistive load. It is commonly used for the characterisation of experimental transducers. However there is a void of any unified discussion focusing on the circuits influence on the transducer, due to electromechanical coupling in the transducer. The electromechanical coupling causes numerous nonlinear effects, any of which can result in inconsistent results and disjointed conclusions of experimental devices. This article seeks to present analytic tools which can be employed for systems of this type and discusses some of the results obtained from these techniques. Along with analysis and characterisation of the circuit dynamics, the results are compared with an experimental device and presented in terms of design of the system and conclusions drawn relating to the optimum operation point.
    Scopus© Citations 10  324
  • Publication
    From two types of electrostatic position-dependent semiconductor qubits to quantum universal gates and hybrid semiconductor-superconducting quantum computer
    Properties of two types of position-dependent electrostatic qubits: eigenenergy-based and Wannier-based, are treated with Schrodinger formalism. Their operating principles are given. The corresponding quantum universal gates for selected qubit types are described and their possible implementation is suggested. The modeling methodology of setting and reading semiconductor qubit is suggested. The interface between superconducting and semiconductor quantum computer is proposed and its implementation and operating principles are described.
      311Scopus© Citations 14
  • Publication
    Semianalytical model for high speed analysis of all-digital PLL clock-generating networks
    In this paper, we propose the model of a network consisting of All-Digital Phase-Locked Loop Network in application to Clock-Generating Systems. The method is based on a solution of a system of non-linear finite-difference stochastic equations and allows us to perform high speed simulations of a distributed Clock Network on arbitrary topology. The result of our analysis show a good agreement with experimental measurements of a 65nm CMOS All-Digital Phase-Locked Loop Network.
      420Scopus© Citations 3
  • Publication
    Mode-locking in a network of kuramoto-like oscillators
    In this paper we consider a network of phase oscillators. We develop the equations that model the time evolution of the phase of each oscillator in the network. The oscillator represents a modified Kuramoto oscillator and in this study we discuss how these modifications are obtained. In the context of this study, we use this network to model a network of PLLs for distributed clock applications. We analyse analytically and numerically the synchronisation modes of this system for different types of the coupling function. We show that depending on the properties of the coupling function, the network displays either multiple coexisting synchronisation modes or only a single synchronisation mode. While in the context of clock generation, multiple synchronisation modes coexisting in the system at the same parameters are a parasitic phenomenon. However in the context of other application such as associative memory models, mode-locking can be seen a useful phenomenon. The results provide a deeper understanding of globally synchronised clock networks with applications in microprocessor design.
    Scopus© Citations 2  399