Distributed cooperative control for stepper motors synchronization

This paper describes the design and simulation of a distributed cooperative control algorithm based on multi-agents to synchronize a group of stepper motors. Modeling of the two-phase hybrid stepper motor in closed loop is derived in d-q rotary reference frame, based on field-oriented control techniques to provide torque control. The simulation obtained by MATLAB-Simulink shows that the distributed cooperative control effectiveness depends on the network topology defined by the graph.Postprint (published version

Voltage recovery influence on three-phase grid-connected inverters under voltage sags

Faults in power systems cause voltage sags, which, in turn, provoke large current peaks in grid-connected equipment. Then, a complete knowledge of the inverter behaviour is needed to meet fault ride-through capability. The aim of this paper is to propose a mathematical model that describes the behaviour of the currents that a three-phase inverter with RL filter inject to a faulty grid with symmetrical and unsymmetrical voltage sags. The voltage recovery process is considered, i.e., the fault is assumed to be cleared in the successive zero-cross instants of the fault current. It gives rise to a voltage recovery in different steps (discrete voltage sag), which differs from the usual model in the literature, where the voltage recovers instantaneously (abrupt voltage sag). The analytical model shows that the fault-clearing process has a strong influence on the injected currents. Different sag durations and depths have also been considered, showing that there exist critical values for these magnitudes, which provoke the highest current peaks. The analytical study is validated through simulations in MATLAB and through experimental resultsPeer ReviewedPostprint (author's final draft

Modeling and control of a three-phase grid-connected inverter under fault conditions

©2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The aim of this paper is to study the behavior of a three-phase inverter with an RL filter powered by a renewable energy source and connected to a grid under fault conditions. The novelty of the work lies in proposing a mathematical model which can be solved analytically. So, a comprehensive analytical solution is given, which can be used to describe the behavior of a three-phase inverter under both symmetrical and unsymmetrical faults. Firstly, a complete mathematical model of the system is given. Secondly, a control is applied for both symmetrical (three-phase faults) and unsymmetrical (one-phase and two-phase faults) conditions, making use of the positive- and negative-sequence components for the latter. Finally, a mathematical model for the whole system Is developed. The analytical approach is valid for any fault conditions, either symmetrical or unsymmetrical, which helps in the understanding of the behavior of three-phase inverters connected to a faulty grid and simplifies its study. The analytical model is validated through simulations carried out in Matlab-simulink™.Peer ReviewedPostprint (published version

Modeling and control of a three-phaseg grid-connected inverter under fault conditions

©2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The aim of this paper is to study the behavior of a three-phase inverter with an RL filter powered by a renewable energy source and connected to a grid under fault conditions. The novelty of the work lies in proposing a mathematical model which can be solved analytically. So, a comprehensive analytical solution is given, which can be used to describe the behavior of a three-phase inverter under both symmetrical and unsymmetrical faults. Firstly, a complete mathematical model of the system is given. Secondly, a control is applied for both symmetrical (three-phase faults) and unsymmetrical (one-phase and two-phase faults) conditions, making use of the positive- and negative-sequence components for the latter. Finally, a mathematical model for the whole system Is developed. The analytical approach is valid for any fault conditions, either symmetrical or unsymmetrical, which helps in the understanding of the behavior of three-phase inverters connected to a faulty grid and simplifies its study. The analytical model is validated through simulations carried out in Matlab-simulink™.Peer Reviewe

Voltage recovery influence on three-phase grid-connected inverters under voltage sags

Peer Reviewe