Conventional direct power control (DPC) technique is a simple and efficient control strategy for three-phase PWM rectifier. However, its performance is deteriorated when the converter is supplied by unbalanced or distorted grid voltages. This paper describes the design and implementation of a new configuration of DPC based on disturbance rejection principle to achieve near-sinusoidal input curr...

This paper examines the proper application of three phase induction motors when supplied by unbalanced voltage. To analyze the effects of unbalanced voltage on torque of the induction motors, it has defined 32 unbalanced points, with 8 different types of voltage unbalance, and four levels of Voltage Unbalanced Factor, measured with Symmetrical Components method. In each unbalanced point the Tor...

A grid connected inverter usually requires voltage and current measurements to control the active and reactive powers as well as the inverter output currents. While voltage sensors are essential to obtain reliable information on the phase angle, these additional components certainly increase the production costs and complexity. In this paper, a voltage-sensorless control scheme for a grid conne...

In the context of a Doubly Fed Induction Generator (DFIG) connected to the utility grid under unbalanced voltage conditions, the controller design needs to ensure additional challenges such as restricting the Total Harmonic Distortion (THD) in grid current, minimizing the pulsations in generated power, torque, dc link voltage etc. apart from facilitating the generator power control. Thus the sc...

The low voltage ride-through (LVRT) capability of the doubly-fed induction generator (DFIG) significantly impacts upon the integration of wind power into the power grid. This paper develops a novel comprehensive control strategy to enhance the LVRT and reactive power support capacities of the DFIG by installing the energy storage system (ESS). The ESS is connected to the DC-link capacitor of th...

due to the increasing interest on renewable sources in recent years, the studies on integration of distributed generation to the power grid have rapidly increased. in order to minimize line losses of power systems, it is crucially important to define the size and location of local generation to be placed. minimizing the losses in the system would bring two types of saving, in real life, one is ...

Wind energy is often installed in rural, remote areas characterized by weak, unbalanced power transmission grids. In induction wind generators, unbalanced three phase stator voltages cause a number of problems, including overheating and stress on the mechanical components from torque pulsations. Therefore, beyond a certain amount of unbalance (for example 6%), induction wind generators are swit...

The incorporation of clean energy sources in the power system is a topic of discussion almost everywhere. After the “wind (farms) of change”, small, dispersed, urban photovoltaic (PV) generators are being installed in the roofs of the buildings, connected to the local Low Voltage (LV) grid. A boost in this type of renewable micro generation is expected in the near future. Due to the domestic lo...

In this paper, a cascaded current–voltage control strategy is proposed for inverters to simultaneously improve the power quality of the inverter local load voltage and the current exchanged with the grid. It also enables seamless transfer of the operation mode from standalone to grid-connected or vice versa. The control scheme includes an inner voltage loop and an outer current loop, with both ...