In this paper, a new approach is proposed for VOLTAGE AND CURRENT HARMONICS COMPENSATION in grid-connected microgrids (MGs). If sensitive loads are connected to the point of common coupling (PCC), COMPENSATION is carried out in order to reduce PCC VOLTAGE HARMONICS. In absence of sensitive loads at PCC, CURRENT HARMONICS COMPENSATION scenario is selected in order to avoid excessive injection of HARMONICS by the main grid. In both scenarios, COMPENSATION is performed by the interface converters of distributed generation (DG) units. Also, to decrease the asymmetry among phase impedances of MG, a novel structure is proposed to generate virtual impedance. At fundamental frequency, the proposed structure for the virtual impedance improves the control of the fundamental component of power, AND at harmonic frequencies, it acts to adaptively improve nonlinear load sharing among DG units. In the structures of the proposed HARMONICS compensator AND the proposed virtual impedance, a self-tuning filter (STF) is used for separating the fundamental component from the harmonic components. This STF decreases the number of phase locked loops (PLLs). Simulation results in MATLAB/SIMULINK environment show the efficiency of the proposed approach in improving load sharing AND decreasing VOLTAGE AND CURRENT HARMONICS.

Introduction: The ionic CURRENTs show nonlinear behavior AND electrical stimuli can influence their activation AND inactivation kinetics. The time constant of depolarizing or hyperpolarizing CURRENT pulses has an important role in the firing behavior of neurons. In the present study, the effects of quasitrpezoidal commAND potentials on L-type calcium channel of somata of F1 neuron in Helix aspesa were investigated.Material AND Methods: In Na+ -K+ free solution, 8 F1 neurons were clamped from holding potentials of -90 or -40 mV to +90 mV by two forms of commAND potentials, rectangular AND quasitrapezodial commAND potentials. Then F1 neurons in the presence of nifedipine (1μM), anorganic blocker of L-type calcium channel, were clamped by two forms commAND potentials.Results: In Na+ -K+ free solution, the quasitrapezoidal commAND potentials in compared with rectangular commAND potentials caused a 36% decerment in peak of Ca2+ CURRENTs AND shift threshold VOLTAGE toward positive potentials. After application of nifedipine, while the quasitrapezoidal commAND potentials caused the threshold VOLTAGE of nifedipine – resistance Ca2+ CURRENTs became more positive but it caused no considerable change in peak CURRENT.Conclusion: The results show that slowly hyperpolarization of membrane potential through the quasitrapezoidal commAND potentials can influence kinetics of ionic channels.

High gain Balun-low-noise-amplifier (LNA) is proposed for tuner of digital televisions (DTVs). The proposed Balun-LNA is based on CS-CG (common-source-common-gate) structure. To improve the isolasion AND frequency response, Balun-LNA has cascode transistors before load resistors. Balun-LNA uses CURRENT-bleeding circuit to increasie transconductance of CS transistor, so that CURRENT-bleeding transistor has transconductance of N-1 times larger than transconductance of cascode transistor. Thereby, transconductance AND CURRENT of CS transistor are increased N times, as N-1 times of CURRENT pass to CURRENT-bleeding transistor. Therefore CURRENT of CG AND CS stages stay identical. Also, Balun-LNA employs a positive feedback to satisfy input impedance matching AND CG transistor has higher transconductance. By increasing transconductance of CS AND CG transistors, the proposed Balun-LNA achieves to high VOLTAGE gain. Accordingly, CG AND CS tansistors have symmetrical CURRENTs AND loads at the differential output of the proposed Balun-LNA. Symmetrical loads cause the balanced differential outputs. This proposed Balun-LNA is designed in 90-nm CMOS technology AND covers the frequency range of 40 MHz to 1GHz. This Balun-LNA achieves the VOLTAGE gain of 22.6 dB, S11 of less than -10 dB AND the Minimum NF of 5 dB. This Balun-LNA operates at the nominal supply VOLTAGE of 2.2v.

In this paper, a new high step-up CURRENT-fed LLC resonant DC-DC converter with a center-tapped transformer is proposed. By selecting the switching frequency to be lower than, but near to, the series resonant frequency of the LLC resonant tank, soft-switching operation of all semiconductors, i.e., zero VOLTAGE switching (ZVS) turn-on of power MOSFETs AND zero CURRENT switching (ZCS) turn-off of diodes is achieved. This leads to lower electromagnetic interference (EMI) AND lower switching losses AND improves the converter efficiency. An interleaved structure is used at the primary side. Thus, input CURRENT ripple is smaller, AND its frequency is twice the switching frequency. Consequently, a smaller input filter is necessary in practice. The converter with 1.2 kW output power AND 760 V regulated output VOLTAGE with 80-200 V input VOLTAGE variations is simulated. The output VOLTAGE is regulated by using asymmetric pulse width modulation (APWM) at 200 kHz switching frequency. Finally, a 700-W prototype has been implemented AND experimental results are also presented to verify the simulation results.

This paper presents a new control method for simultaneous COMPENSATION of instantaneous reactive power AND CURRENT HARMONICS by parallel active filters (PAFs). Reference compensating CURRENTs of PAF are calculated using the subtraction of instantaneous power from its average value. In this way, it is possible omitting high/low pass filter(s) from the control circuit of PAF, which usually results in phase shift AND magnitude change of alternating components of instantaneous power. It is possible regulating the DC side VOLTAGE of PAF using a closed loop control circuit, easily. The presented method is compared with the classical p-q theory method through simulation results. A simple model for controlling the switches of power electronic converters is offered that is usable in PSCAD/EMTDC simulation package. Experimental results verify the validity of presented control strategy in generating of reference COMPENSATION CURRENTs.

This paper analyzes the harmonic performance of thyristor controlled series capacitors (TCSCs) in power systems AND proposes an effective method for their control AND limitation in the compensated line. This is performed by proper selection of TCSC elements (capacitance AND inductance) AND by introducing a new method for adjusting its firing angle such that high line loadability as well as low HARMONICS generation is achieved. Finally, a TCSC is designed, modeled, simulated AND analyzed. The main contribution is the consideration of power quality phenomena, as well as loadability in the TCSC control scheme.

A High-gain, fully balanced preamplifier is presented. The proposed structure advantages flipped VOLTAGE follower scheme to achieve a compact CURRENT conveyor with very low input impedance. The presented CURRENT conveyor then is used as a core element to realize a high-gain, gm-enhanced trans-conductance amplifier. The presented amplifier is suitable for application as a preamplifier. The high gain of amplifier makes it very suitable to be configured in a feedback form to deliver a high-precision predefined or programmable amplification gain. The proposed structure draws a very low power of 150nW from a 0.6V supply VOLTAGE. The Spectre Post-layout simulations with TSMC 180nm CMOS technology have been performed. The proposed amplifier exhibits an open-loop DC gain of 141.5dB AND 3-dB frequency bANDwidth of 2.4kHz at 60dB closed-loop configuration. The load capacitance is set to be 5pF. The proposed structure also delivers high CMRR AND PSRR values of 148.3dB AND 153.7dB, respectively.