Simplified Control Scheme of Unified Power Quality Conditioner based on Three-phase Three-level (NPC) inverter to Mitigate Current Source Harmonics and Compensate All Voltage Disturbances

Abstract

-This paper proposes a simplified and efficient control scheme for Unified Power Quality Conditioner (UPQC) based on three-level (NPC) inverter capable to mitigate source current harmonics and compensate all voltage disturbances perturbations such us, voltage sags, swells, unbalances and harmonics. The UPQC is designed by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The dc voltage is maintained constant using proportional integral voltage controller. The shunt and series AF are designed using a three-phase three-level (NPC) inverter. The synchronous reference frame (SRF) theory is used to get the reference signals for shunt and the power reactive theory (PQ) for a series APFs. The reference signals for the shunt and series APF are derived from the control algorithm and sensed signals are injected in tow controllers to generate switching signals for series and shunt APFs. The performance of proposed UPQC system is evaluated in terms of power factor correction and mitigation of voltage, current harmonics and all voltage disturbances compensation in three-phase, three-wire power system using MATLAB-Simulink software and SimPowerSystem Toolbox. The simulation results demonstrate that the proposed UPQC system can improve the power quality at the common connection point of the non-linear load.

Unified Power Quality Conditioner Model Based with Series and Shunt Filters

“…The dc voltage is maintained at a constant value which is equal to the reference value Vdc=600 V by using 2DoFPI voltage controller as can be shown in Figure 21. This result is much better than results reported in [26]- [27]. This controller is used in the DC voltage loop for reduction of unwanted power loss inside the inverter [28].…”

Performance Analysis of Universal Power Quality Conditioner Systems Based on Seven-level NPC Inverter Using PD-SPWM with Fuzzy Control Scheme

“…The three leg shunt active filter are connected ahead of a series filter using a small capacity rated inductive filter used to absorb current harmonics, compensate reactive power and negative-sequence current. The UPQC strategy control is based on the synchronous reference frame detection method for the shunt AF and instantaneous reactive power theory for the series AF [16]. These two VSCs require two control algorithms to generate reference voltages and the reference currents.…”

“…However, due to power handling capabilities of power semiconductors, these inverters are limited for low power applications [15]. The neutral-point-clamped (NPC) converter topology has been the center of research and development effort for several applications, including medium-and high-voltage electric motor drives, static compensators (STATCOMs) and other utility type of power electronic systems for almost three decades now [16,17]. Their advantages are lower voltage harmonics on the ac side, smaller filter size, lower switching losses, lower electromagnetic interference, lower voltage stress of power semiconductors, and lower acoustic noise; these advantages can reduce the construction cost of active filter in the medium and high voltage applications [18].…”

Efficient Control Scheme for Five-level (NPC) Shunt Active Power Filters Based on Fuzzy Control Approaches

“…However, due to power handling capabilities of power semiconductors, these inverters are limited for low power applications. Three-level inverters have been successfully employed in medium power applications in the past years [6,7]. The five level (NPC) are used in high power applications, Their advantages are lower voltage harmonics on the ac side, smaller filter size, lower switching losses, lower electromagnetic interference, lower voltage stress of power semiconductors, and lower acoustic noise.…”