Analysis and effective controller design for the cascaded H‐bridge multilevel APF with adaptive signal processing algorithms

This paper develops a simple design of unit cells to be taken in use in series-connected multilevel inverters. The proposed structure not only reduces the part counts efficiently but also increases the number of generated levels in the output voltage. By aggregating the cascaded series-connected units as the basic module, the proposed structure follows one H-bridge circuit. The basic module acts as the initial stage in direct current/alternative current conversion within which all the positive and zero levels are produced. Afterwards, the H-bridge circuit affords the production of symmetric sine-wave by realizing negative levels.To assure the expected operational objectives, we developed three different algorithms to determine the magnitude of input direct current voltage sources. Moreover, to further investigate the proposed structure, different switching algorithms such the fundamental switching frequency and pulse width modulation level shifting approaches are implemented and compared with each other. Extensive numerical and experimental studies are conducted to yield in a suitable evaluation platform. The obtained results demonstrate a superior performance of the proposed structure rather than the conventional topologies.depreciate the satisfactory performance of the proposed structure for low levels output voltages. For these cases, the THD content increases. This point is easily recognized in Figure 22. However, by increasing the number of levels, we obtained a more sinusoidal and clean waveform. Thus, a higher service quality is guaranteed. This in turn increases the count of power electronics devices and Figure 18. Experimental results for the proposed nine-level structure. (a) Basic module voltage (V o1 + V o2 ), (Time/div = 5 ms), and (Voltage/div = 2 V by 1:10 probe). (b) Sinusoidal output voltage waveform. (c) Output current waveform. [Colour figure can be viewed at wileyonlinelibrary.com]

Section: Introductionmentioning

confidence: 99%

A simple unit cell structure for an efficient sketch of series‐connected multilevel inverters

Choupan

Nazarpour

Golshannavaz

2017

“…The STATCOM consists of four 3-level 48-pulse voltage-source gate turn-off inverters and two series-connected 3-mF capacitors [36][37][38][39]. The STATCOM consists of four 3-level 48-pulse voltage-source gate turn-off inverters and two series-connected 3-mF capacitors [36][37][38][39].…”

Section: Case Study Ii: Unbalanced Voltage Regulation For Microgrid Amentioning

confidence: 99%

“…The DG sources are modeled as an equivalent balanced three-phase current source for simplicity. The STATCOM consists of four 3-level 48-pulse voltage-source gate turn-off inverters and two series-connected 3-mF capacitors [36][37][38][39]. The STATCOM system control is represented in Figure 8.…”

Section: Case Study Ii: Unbalanced Voltage Regulation For Microgrid Amentioning

confidence: 99%

Modeling of unbalanced three‐phase driving‐point impedance with application to control of grid‐connected power converters

Wong

Tse

et al. 2015

The dq transformation is widely used in the analysis and control of three-phase symmetrical and balanced systems. The transformation is the real counterpart of the complex transformations derived from the symmetrical component theory. The widespread distributed generation and dynamically connected unbalanced loads in a three-phase system inherently create unbalanced voltages to the point of common coupling. The unbalanced voltages will always be transformed as coupled positive-sequence and negative-sequence components with double-frequency ripples that can be removed by some filtering algorithms in the dq frame. However, a technique for modeling unbalanced three-phase impedance between voltages and currents of same sequences or of opposite sequences is still missing. We propose an effective method for modeling unbalanced three-phase impedance using a decoupled zero-sequence impedance and two interacting positive-sequence and negative-sequence balanced impedances in the dq frame. The proposed method can decompose a system with unbalanced resistance, inductance, or capacitance into a combination of independent reciprocal bases (IRB). Each IRB basis belongs to one of the positive-sequence, negative-sequence, or zero-sequence system components to facilitate further analysis. The effectiveness of this approach is verified with a case study of an unbalanced load and another case study of an unbalanced voltage compensator in a microgrid application.

“…In order to compensate harmonic currents, the use of shunt active power filter (SAPF) has been proposed [1][2][3][4]. Such power filters consist of a converter, a passive filter, and a controller, as schematized in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Application of the modified IDA‐PBC for shunt active power filters control

Serra¹,

Angelo

Forchetti

2016

Summary The design of a passivity‐based nonlinear controller for a shunt active power filter to be used for the compensation of harmonic currents consumed by nonlinear loads is presented in this paper. The main objective of designed controller is to inject the necessary compensation current into the system so that the grid current is sinusoidal and balanced, regardless of whether the grid voltage is unbalanced and/or distorted. The references for the compensation currents are obtained from applying the pq theory. The controller is designed on the basis of a modified interconnection and damping assignment technique, which allows solving a tracking control problem. An integral action controller is added to the proposed controller using the same design technique, in order to eliminate the errors produced by parameter variations or uncertainties. The behavior of the proposed control strategy is validated through simulation using a realistic model, which includes converter switching and losses, grid distortion, and parameter variations. Copyright © 2016 John Wiley & Sons, Ltd.