Power quality improvement using 18 sector algorithm based direct power control

Abstract

Predefined lookup table inspired direct power control techniques have been used mostly for active front end rectifiers. As an intransigent switching pattern is followed here, the effectiveness of the converter is hampered when the operating parameters change. Apart from that, the switching table design is attributed only to the sign of power demand. In this work, the magnitude of the power demand along with its sign is considered for the selection of the switching vector. The phase angle of the grid voltage vector is estimated using the virtual flux technique. The magnitude of active and reactive powers transferred from the grid to the converter depends on the switching vector of the converter and the phase angle of the grid voltage vector. Conventional methods of Direct Power Control have used 12 sector-based divisions. The switching vector is selected depending on the 30 slabs to which the grid voltage vector belongs. With the advent of high-speed microcontrollers, it is possible to improve the accuracy of the conventional DPC with increased resolution in the switching vector selection. So, in this work, one complete cycle of the grid voltage vector is divided into 18 sectors instead of 12 sectors to locate the grid voltage vector more accurately. Finally, a redesigned algorithm is customed to select the most suited vector that meets the power demands of the active front end rectifier at that particular phase angle. The feasibility of the proposed technique is verified with MATLAB simulations and experiments conducted in the laboratory.

Harmonic and Sequence Component Estimation by a Novel Method

“…According to the IEEE standard, 1459-2010, [12] the voltage and current rms values are estimated from their respective sample values of voltage signals using (3)…”

“…Large power converters which can be modelled as a non-linear load also form a large source of harmonics. Hence researchers have been trying to improve system performance by improving the converter control algorithms as described in [3], [4]. Estimation of the harmonic components in a power system have great contribution in the filter designing aspect.…”

An advanced virtual flux integrated multifold table‐based direct power control with delay compensation for active front‐end rectifiers

“…Even with all of these advanced DPC approaches, the traditional switching table‐based DPC is still favored where a simple control structure with less computational burden is the design requirement. Hence, an algorithm‐based vector selection method that functions through a dynamic switching table can address the issue of using static lookup table in the classical ST‐DPC 21,22 . The algorithm DPC improves steady‐state behavior as well as improves the dynamic performance.…”

“…Hence, an algorithm-based vector selection method that functions through a dynamic switching table can address the issue of using static lookup table in the classical ST-DPC. 21,22 The algorithm DPC improves steady-state behavior as well as improves the dynamic performance.…”