Improved Active Power Filter Performance Based on an Indirect Current Control Technique

Abstract

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.

A Refined Self-Tuning Filter-Based Instantaneous Power Theory Algorithm for Indirect Current Controlled Three-Level Inverter-Based Shunt Active Power Filters under Non-sinusoidal Source Voltage Conditions

“…In other words, it changes the DCC-based operation to ICC-based operation. Unlike DCC-based operation, ICC-based operation which has been reported in [43][44][45]47] to possess exact information on switching ripples existing in the source current, allows accurate generation of reference currents to continuously control the operation of the SAPF and thus eliminates any unnecessary problem caused by SAPF switching operations.…”

“…To date, the conventional STF-pq theory algorithm still produces a non-sinusoidal reference current [7,40,42] and thus forces the SAPF to operate based on a direct current controlled (DCC) scheme [43][44][45]. From previous literature [45][46][47], it is revealed that the SAPF switching operation produces switching ripples which potentially degrade the THD value of the mitigated source current.…”

“…As a result, a mitigated source current of higher THD value is produced. Although the indirect current controlled (ICC) scheme which generates PWM switching pulses based on error signals resulting from the difference between the actual source current and its sinusoidal reference current counterpart [2,22,43,44] has been proven to overcome this weakness of the DCC scheme, there is still no work on STF-pq theory which has been conducted together with ICC scheme. In fact, the working principle of the conventional STF-pq theory algorithm has limited its application to DCC schemes.…”

“…From previous literature [45][46][47], it is revealed that the SAPF switching operation produces switching ripples which potentially degrade the THD value of the mitigated source current. However, the DCC scheme which generates pulse-width modulation (PWM) switching pulses based on error signals resulting from the difference between the measured injection current and its non-sinusoidal reference current counterpart [43][44][45], does not possess accurate information on the characteristics of the actual source current. Therefore, even if the source current is contaminated by switching ripples, DCC scheme is unable to alleviate the problems due to a lack of exact information.…”

A Simplified Synchronous Reference Frame for Indirect Current Controlled Three-level Inverter-based Shunt Active Power Filters

“…Moreover, the ICC scheme has a simpler control structure which involves a lower number of calculations [31], [34] and can be implemented with a lower number of sensors [30], [34]. As a result, it effectively reduces the system requirements for practical implementation.…”