Three‐level hysteresis current control strategy for three‐phase four‐switch shunt active filters

Abstract

In this study, a three-level hysteresis current-control (HCC) strategy is proposed for three-phase four-switch shunt active power filters. The four-switch topology which utilises four switching devices together with two series connected capacitors is able to reduce the cost, switching losses and improve the reliability of system. In this topology, when the current control of phases A and B is achieved successfully, the current control of phase C which is connected to the midpoint of the series connected capacitors is achieved automatically. The current control is achieved by using a three-level HCC strategy. An important consequence of using this control strategy is that it enables access to the zero level of the input voltage of active filter so that a switching device is only switched when the current error is negative, while it remains off when the current error is positive. Furthermore, the imbalance in the capacitor voltages is eliminated by adding a feedback term (the difference in the capacitor voltages multiplied by a suitable gain) to the current control. The proposed control strategy offers a reduced switching frequency, losses and cost. The steady-state and dynamic performance of the proposed control strategy is verified through simulations and experimental studies.

Operation of three-level single-phase half-bridge NPC inverter-based shunt active power filter under non-ideal grid voltage condition with sliding mode controller

“…One of the reasons of this imbalance comes from a dc offset caused by the system's initial condition. The other reason is the non-equal capacitance (Cdc1 ≠ Cdc2) values in practice [8], [9]. As clearly explained in [10] Fig.…”

“…For the sake of simplicity, the SSOGI configuration can be separated into two subsystems: self-tuning and SOGI. The transfer functions of ( ) and ( ) corresponding to input ( ) in the s-domain can be recalled from [9] as follows…”

An overview of power quality enhancement techniques applied to distributed generation in electrical distribution networks

“…Fig. 1-b is a simple display of shunt active power filters, as it is shown APF is compensating the nonlinear load current by injecting the same nonlinear current that load absorbs from the grid, so that the grid current will be sinusoidal [66,67] Ongoing researches in this field are concentrated over novel control methods of shunt active power filters and also new applications for shunt APFs [68][69][70][71][72][73][74][75][76][77][78][79][80]. More detailed analysis of main topologies of shunt active power filters is done in [81].…”

Design and implementation of a cascaded transformer coupled multilevel inverter-based shunt active filter under different grid voltage conditions

“…For an effective application of a SAF, the control technique must be suitable to generate required compensation current during ideal and nonideal condition. In the recent past, many literatures have been addressed focusing on various methods of reference current extraction for significant harmonic elimination . Out of which, a very well‐known control technique, p‐q theory, provides significant harmonic elimination capability during balanced load condition; however, it requires complex mathematical transformation and has to deal with synchronization issues.…”

“…In the recent past, many literatures have been addressed focusing on various methods of reference current extraction for significant harmonic elimination. [14][15][16] Out of which, a very well-known control technique, p-q theory, 17 provides significant harmonic elimination capability during balanced load condition; however, it requires complex mathematical transformation and has to deal with synchronization issues. By the application of instantaneous active and reactive current 18 (i d -i q ) strategy, the system is capable to provide a good dynamic response and suitable in balanced sinusoidal source voltage condition.…”