PQ, DQ and CPT control methods for shunt active compensators — A comparative study

Abstract

This paper investigates three different control techniques for controlling shunt active compensators for harmonic, reactive power and unbalance compensation. The considered methods were the instantaneous real and imaginary power theory (PQ), the Conservative Power Theory (CPT) and the synchronous reference frame method (DQ). So, the major goal is to explore the main similarities and differences in terms of steady state performance, dynamic response and computational complexity of each compensation method. Additionally, the paper also discusses how to achieve selective compensation by means of every technique, by means of suitable power and current decompositions. A three-phase grid with unbalanced non-linear load and non-negligible line impedance was used for comparing the approaches under ideal and deteriorated voltage conditions. I.978-1-4799-5776-7/14/$31.00 ©2014 IEEE

Grid-Connected Symmetrical Cascaded Multilevel Converter for Power Quality Improvement

“…The CPT [14] allows for the decomposition of the instantaneous currents into different orthogonal current terms, valid for single-and multiphase systems, independent of the voltage conditions. Such components can be applied as reference signals to shunt active filters [15], [16], multifunctional converters [28], [36], [37], or for the design of filter elements, such as semiconductor switches, inductors, and capacitors. Moreover, the resulting compensation strategies are highly flexible since the decompositions allow for the selective identification and minimization of different disruptive effects (nonlinearities, unbalances, and reactive power).…”

“…However, there are alternative methodologies that may prove more flexible than the ones mentioned above, providing a simpler way to compensate for disturbances selectively, and simplifying our understanding of the related electrical characteristics. In this context, this paper proposes to use conservative power theory (CPT) [14]- [16] as an alternative framework for the development of electronic power processors (EPP), especially to the design of physical elements and to the definition of selective compensation strategies for multifunctional grid-tied inverters or shunt active filters. This is because the proper choice of which portions should be compensated is a critical factor for the project since the actual nominal value directly influences the requirements of the active and passive elements of the EPP, and thus, the financial cost of their installations.…”

Multifunctional Control Strategy for Asymmetrical Cascaded H-Bridge Inverter in Microgrid Applications

“…Reactive current is given by: (10) where represents the load equivalent reactivity. Void current is the remaining current term, which depends on the voltage and the current distortion: (11) By definition, all the terms are orthogonal (decoupled) to each other. Then: (12) Thus, the apparent power is calculated as: (13) The active power ( ) is related to the average power transfer.…”

Comparison of Shunt Active Power Filter Control Strategies for Harmonic Compensation in a Paper Industrial Factory

“…Figure 2 shows the block diagram of the shunt active filter based on the P-Q theory introduced by Akagi in 1983 [2], [3], [4], [5], [6].…”