We study definability of second-order generalized quantifiers. We show that the question whether a second-order generalized quantifier Q1 is definable in terms of another quantifier Q2, the base logic being monadic second-order logic, reduces to the question if a quantifier Q1 is definable in FO(Q2, <,+,×) for certain first-order quantifiers Q1 and Q2. We use our characterization to show new de...

The combined effects of deviation from ideal in integrator upon the characteristics of the integrators. Inverting and noninverting magnitude and phase on the performance of integrator-based active filters integrators for use in active filters which are independent of first-order and is investigated. The limitations of using the integrator Q-factor as a second-order operational amplifier time co...

This article presents an enhanced frequency adaptive demodulation technique for grid-synchronization of grid-connected converters in variable condition. Demodulation works by generating demodulated voltages which contain undesired double components. As a result, high-order low-pass filters with high cutoff are required to eliminate the reduces dynamic performance. Frequency enhances performance...

Among the various faults of power transformers, winding are particularly common. It is known that short-circuit parameters can reflect condition, so on-line identification great significance for monitoring transformer health. An instantaneous phasor extraction method based on Second-Order Generalised Integrator Frequency-Locked Loop introduced, and then an algorithm proposed. In this algorithm,...

Various faults and disturbances often make the grid unbalanced distorted. To grid-connected converters resilient to distorted grid, real-time estimation of voltage sequences are essential. Adaptive-observer based grid-synchronization techniques very suitable for this purpose. In paper, a comparative analysis three recently proposed adaptive observer-based technique presented frequency sequence ...

In this work, we present a new proposal for the second-order Adaptive Sigma Delta Modulation (ASDM). The new proposed Adaptation scheme is based on using Operational Transconductance Amplifier (OTAs) as an Integrator and as an Amplifier to adapt the quantizer stepsize to control the voltage gain by feedback the quantizer output through adaptation scheme. The stepsize is changing up or down by t...