Arash Momeneh

Frequency-Modulation Control of a DC/DC Current-Source Parallel-Resonant Converter

This paper proposes a frequency-modulation control scheme for a dc/dc current-source parallel-resonant converter with two possible configurations. The basic configuration comprises an external voltage loop, an internal current loop, and a frequency modulator: the voltage loop is responsible for regulating the output voltage, the current loop makes the system controllable and limits the input current, and the modulator provides robustness against variations in resonant component values. The enhanced configuration introduces the output inductor current as a feed-forward term and clearly improves the transient response to fast load changes. The theoretical design of these control schemes is performed systematically by first deriving their small-signal models and second using Bode diagram analysis. The actual performance of the proposed control schemes is experimentally validated by testing on a laboratory prototype.

Transient analysis of PV-based industrial microgrids between grid-connected and islanded modes

This paper presents a networked control scheme for a photovoltaic-based industrial microgrid to adaptably operate in both grid-connected and islanded modes, and even to transfer smoothly between these two modes. The control scheme is mainly based on the droop method for active and reactive power sharing by means of voltage and frequency regulation. In addition, to get a smooth transfer between islanded and grid-connected modes, a phase-locked loop is also used in the control system. This loop is only activated during islanded mode to eliminate the phase deviation between the voltages in both sides of the point of common coupling switch. The output of this loop is send to all power units following a one-to-all communication scheme with low bandwidth. Finally, selected simulation results are reported in order to prove the effectiveness of the control scheme.

Design and control of a small-scale industrial microgrid in islanding mode

Microgrid increases the reliability and quality of supply of industrial and commercial buildings. The operation in islanding mode is a challenging issue due to the limited energy available and the lack of a main grid for synchronizing purposes. This paper presents both the design of a small-scale industrial microgrid and a hierarchical control strategy for islanding mode operation. The control scheme consists of primary and secondary layers to provide good power sharing among generators and elimination of voltage and frequency deviations in steady state, respectively. In addition, the control strategy mitigates undesired circulating currents and reduces power losses. Selected simulation results are included to verify the system performance.

New inductive contactless energy transfer system for residential distribution networks with multiple mobile loads

This paper proposes a novel inductive contactless energy transfer system for residential distribution networks. The system is based on a resonant inverter with sliding transformers, allowing high flexibility (the connection point of the loads is movable) and high safety (electrical shocks are avoided). A new resonant topology for driving the sliding transformers is proposed which behaves as an AC high-frequency voltage source. A very interesting feature of this voltage source is that the amplitude of the output voltages is nearly constant and independent of the load consumption. The paper presents a design procedure for calculating the components and parameters of the resonant circuit. The performance of the complete contactless system is evaluated, especially the efficiency and the transient response. The reported results show good performance validating the proposed topology.

Active damping based on Ackermann's formula for a three-phase voltage source inverter with LCL filter

This paper presents an active damping method in natural frame for a three-phase voltage source inverter with LCL filter. The proposed method is based on the pole placement technique via Ackermanns formula. This approach is used to obtain the proper sliding surface vector coefficients to emulate a virtual resistor in series with the capacitor filter. Besides a well-known method in the literature have been used to obtain three decoupled controllers in natural frame. The stability is theoretically studied and experimental results shows the validity of this proposal.

Multi-objective optimized daily schedule for an efficient solar-based industrial microgrid

In this paper, an optimal daily management for a solar-based industrial microgrid is proposed by analyzing two different load profiles. For each profile, the first step is to find the optimum size of the battery bank in order to identify the best daily configuration. The second step is to solve a multi-objective optimization problem, which takes into account economic evaluation indices (such as the initial investment, replacement, maintenance cost and the cost related to selling or purchasing energy to or from the grid) as well as the loss of power-supply probability index for evaluating system reliability. To solve the multi-objective optimization problem, first the weighted-sum method is used to convert it into a single objective optimization problem. Second, the new formulation is solved using an enhanced version of the bacterial foraging algorithm.

Architecture and design of an inductive contactless energy transfer system with two mobile loads for residential applications

Inductive contactless energy transfer systems with multiple mobile loads are very complex systems. Main challenges of these systems are to propose a suitable architecture and to design their power components. These challenges are particularly more noticeable in residential areas where various types of consumers (loads) are expected. This paper introduces a new architecture and design guidelines for a high-frequency resonant transformer operating with frequency modulation. The design process includes the effects of 1) the resonant frequency, 2) the magnetizing inductance, and 3) the characteristic impedance. The excellent performance of the designed system is validated by simulation results.

Sliding mode control of three-phase grid-connected voltage-source inverter with vector Operation

This paper presents a sliding mode control for a three-phase grid-connected voltage source inverter with vector operation. The design of closed-loop system is based on the sliding-mode theory, and it is carried out with the help of a converter large-signal dynamic model. The closed-loop system improves the transient response and minimizes the steady-state error. Essentially, the contribution of this paper is as follows: the dynamic model for the tree-phase grid-connected inverter with vector operation and the proposed sliding-mode control scheme. Experimental results are provided using a fully-digital control system in order to validate the theoretical predictions.