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Microgrids are a growing trend toward a new power distribution system that allows for a high penetration of renewable distributed generation, electrical energy storage systems and controllable loads. This modern concept exploits the advances in electronic technology to improve efficiency, reliability, and flexibility, while reducing cost and size. Furthermore, microgrids can operate in a grid-connected...
Aiming at that it is difficult to choose the value of virtual damping(VD) in passivity-based controller of the Boost converter, this paper proposes an approach which can be used to calculate and optimize the value of VD. The range of VD can be determined by constraining overshoot of the current response of Boost converter. The optimal VD can be found in the range of VD by genetic algorithm(GA) and...
Vector control is the most commonly used control strategy for modular multilevel converter (MMC) based HVDC system. However, due to the complicated structure of MMC, there is no precise mathematical model for the outer DC voltage loop. The conventional model ignores the capacitor voltage dynamics, and the AC voltage boosted operation scenario is not considered. This paper proposes a small signal model...
LLC resonant converters are widely employed in industrial applications due to their high efficiency and power density. The design of closed-loop controllers for these converters is particularly challenging due to its non-linear behaviour and many different operating modes. The traditional linear techniques that are usually employed for this application require complex analysis or the use of empirical...
With the increasing application of photovoltaic, the micro-inverter with interleaved flyback module operating in continuous conduction mode (DCM) and discontinuous conduction mode (DCM)is more popular. However, its difficult to control output current of interleaved flyback micro-inverter because the transfer function has right-half-plane (RHP) zero in CCM and low gain in DCM. To solve this problem,...
In this paper we present a new computational method for calculating thermal transfer impedances between a few separate locations of a given physical structure aimed at the implementation into a field-solver based on the SUNRED (SUccessive Node REDuction) algorithm. The order reduction was done by the balanced truncation method. We tested the method on a simplified LED package in 3D. Results obtained...
This paper is a step forward in the analysis of generalized time-fractional telegrapher's equation, derived as the mathematical model describing transmission line. Using fractional calculus as a mathematical tool for generalization, memory effects of inductive and capacitive phenomena are included in model. The effect of electrical charge accumulation along the line is taken into account by the topological...
In this paper a Matlab noise model is developed for a two-integrator filter Biquadratic section (Biquad) using second-generation current conveyors (CCII). The noise model of the AD 844 current-feedback operational amplifier (CFOA), the input circuit of which is a CCII, is used for our analysis. However, because a correct noise model of the AD 844 does not exist in Pspice, a new noise model of the...
Using current conveyors, we present six different current-mode circuits approximating fractional-order low-pass transfer function. Proposed circuits always use four active elements, three capacitors and seven or five resistors, whereas all are grounded. We show that the usage of only eight passive elements is sufficient to approximate a (1 + α)-order system (0 < α < 1) and can even provide better...
This paper proposes a discontinuous current mode (DCM) feedback current control for a single-phase grid-tied inverter in order to minimize a LCL filter without worsening total harmonic distortion (THD) of a grid current. In DCM, there are two nonlinearities occurring in the transfer functions; the first non-linearity occurs in the duty-ratio-to-current transfer function which worsens the current command...
This paper presents the circuit simulator for noise analysis of switched-capacitor (SC) circuits using adjoint network approach in python environment. Adjoint network approach is a simpler method for noise calculations in SC circuits because just solving of the adjoint network gives the node voltages which are transfer functions (output is injected with unit current source in this approach) these...
Simulation of complex hardware circuits is the basis for many EDA tasks and is commonly used at various phases of the design flow. State-of-the-art simulation tools are based upon discrete event simulation algorithms and are highly optimized and mature. Symbolic simulation may also be implemented using a discrete event approach, or other approaches based on extracted functional models. The common...
A system and source joint estimation method for EM emission modeling is proposed in this paper. Based on the priori knowledge, i.e., the transfer function of system is smooth and the form of source signal was already known, the paper using joint estimation method to solve modeling problems when measured only the emission amplitude spectra at some ports. Experimental results verify the method could...
In both the traditional diode uncontrollable rectifier circuit and thyristor phased rectifier circuit, the shortcomings of low power factor are difficult to overcome. PWM rectifier circuit is to use full control power switch devices and adopts PWM control mode of rectifier circuit, through the adoption of appropriate control strategies and PWM modulation technology, PWM rectifier circuit can realize...
The objective of this paper is to develop discrete-time models for grid-connected converters in synchronous reference frame. As the current controllers are generally implemented in microprocessors, some problems that arise in the discrete-time domain are addressed. The time delay of the digital implementation is modeled and its effect on the synchronous transformation is discussed in this paper. Additionally,...
As desired in mobile applications, S-Hybrid converter that merges switched-inductor and switched-capacitor operations can significantly relieve on-board thermal issues by distributing heat loss over an input cable and allowing zero onboard inductor. In this architecture, the input cable is used as inductor for power conversion. This paper presents detailed smallsignal analysis of S-Hybrid converter...
This paper presents a current controller for an automotive LED driver based on a zero-voltage switching (ZVS) Ćuk converter using planar integrated magnetics. The driver outputs regulated dc current through a string of N = 1–12 LED's, which implies the need to operate over a wide output voltage range (approximately 3–40 V). It is found that the low-frequency gain of the duty-cycle-to-output-current...
DC microgrids are envisioned to be EPDS (Electronic Power Distribution Systems) composed of COTS (Commercial-Off-The-Shelf) converters. Naturally, these converters will determine the dynamic behavior of the system. Besides, unlike classic EPDS, microgrids are highly variable due to the intermittent behavior of the renewable sources and customer consumption. In this context, there is not an accepted...
Poly-phase systems have been used for many years in machines and recently in wind power generations. They usually are built by a dual three-phase system, shifted by 30 electrical degrees from each other and with no neutral connection. Typically, this system employs a twelve-pulse diode rectifier to converter ac to dc voltages. However, it may be improved if an active rectifier is used, because it...
In this paper the proposed configuration of a digitally controllable non-inverting RC integrator, employing 4-terminal CFOA is an object of analysis and simulation modeling. Based on a theoretical analysis of the circuit the equations for the transfer functions and formulas for the related electrical parameters are obtained. By using the synthesized circuit of an integrator a programmable CFOA-based...
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