Coordinated Control Strategy for Harmonic Compensation of Multiple Active Power Filters

Abstract

In order to minimize the harmonic distortion rate of the current at the common coupling point, this paper proposes a coordinated allocation strategy of harmonic compensation capacity considering the performance of active power filters (APF). On the premise of proportional distribution of harmonic compensation capacity, the harmonic compensation rate of each APF is considered, and the harmonic current value of each APF to be compensated is obtained. At the same time, the communication topology is introduced. Each APF takes into account the compensation ability of other APFs. Finally, three APFs with different capacity and performance are configured at the harmonic source to suppress the same harmonic source, and the harmonic distortion rate is reduced to 1.73%. The simulation results show that the strategy can effectively improve the compensation capability of the multiple APF cascaded system to the power grid without increasing the installed capacity.

Distributed Control Scheme for Clusters of Power Quality Compensators in Grid-Tied AC Microgrids

“…The control objectives commonly include compensating current imbalance and harmonics while managing the reactive power at specific points of a grid-tied MG system. For this, the use of dedicated power quality compensators (PQCs) based on a combination of SAPFs and STATCOMs is a valid option explored by many authors in the literature, such as in [6,[9][10][11]. However, these early solutions require additional hardware in the system, increasing costs.…”

“…However, these early solutions require additional hardware in the system, increasing costs. For example, in reference [11], the harmonic distortion of the current at the PCC is reduced by a coordinated allocation strategy of APFs. The proportional distribution of harmonic compensation is performed by a central controller, which estimates weighting parameters using average values of the current and estimated harmonic compensation rates.…”

“…For compensation over multiple buses, groups of PQCs, physically close to each other, are considered. Unlike individual PQCs per bus, a cluster of PQCs allows compensation of higher powers by combining the capacity of multiple PQCs [11,17]. Thus, a cluster of PQCs could be viewed as an alternative to high-power FACTS (like multi-level topologies [12]).…”

“…where S max i is the maximum apparent power of the PQC and c cl n > 0 is a control gain which modifies the dynamic response of the consensus in the clth cluster. When (11) is applied into (9), it allows sharing the effort of compensating power, NA, between PQCs according to their maximum available power.…”

“…Delay (τ) values of 0, 100, and 200 (ms) are tested. These values are selected because of their gradual proximity to the convergence rate in the design of (11), which is close to 500 (ms) for Cluster #1 and 1500 (ms) for Cluster #2 when using Table 3.…”