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1

An Adaptive Control Strategy for a Low-Ripple Boost Converter in BLDC Motor Speed Control

Wang Haifeng, Zhang Haili

Power Electronics and Drives

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2021

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Vol. 6 (41)

242--259

EN

Conventional boost converters are widely used for connecting low-voltage power sources and inverters in motor control. However, a large filter capacitor bank is often used to reduce DC-link ripples that occur when an inverter is connected to a boost converter. Otherwise, significant voltage and current perturbations can impact on battery performance degradation and cause torque ripple, speed ripple and vibration in brushless DC (BLDC) motors. To suppress the converter’s DC-link ripple, this paper proposes a new control strategy for boost converter controller to generate low-ripple DC-link voltage or current at different motor speeds. In the proposed method, observers are designed to adaptively estimate the DC-link voltage and current harmonics. The harmonic terms are used as feedback signals to calculate the DC converter’s duty cycle. The entire control model is implemented on an embedded system, and its robustness is verified by simulation and experimental results that show the DC-link voltage and current ripples can be reduced by about 50% and 30%, respectively.

2

Combination of feedback control and spring-damper to reduce the vibration of crane payload

Nguyen Trong Kien

Archive of Mechanical Engineering

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2021

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LXVIII, nr 2

165--181

EN

Operating cranes is challenging because payloads can experience large and dangerous oscillations. Anti-sway control of crane payload can be approached by the active methods, such as feedback control, or passive methods. The feedback control uses the feedback measurement of swing vibration to produce the command sent to a motor. The feedback control shows good effectiveness, but conflict with the actions of the human operator is a challenge of this method. The passive method uses the spring-damper to dissipate energy. The passive method does not cause conflict with the human operator but has limited performance. This paper presents the combination of two methods to overcome the disadvantages of each separate one. The passive method is used to improve the efficiency of the feedback method to avoid conflicts with the human operator. The effectiveness of the combination is simulated in a 2D crane model.

3

Input reconstruction by feedback control for the Schlögl and FitzHugh–Nagumo equations

Maksimov Vyacheslav, Trlötzsch Fredi

International Journal of Applied Mathematics and Computer Science

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2020

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Vol. 30, no. 1

5--22

EN

Dynamical reconstruction of unknown time-varying controls from inexact measurements of the state function is investigated for a semilinear parabolic equation with memory. This system includes as particular cases the Schlögl model and the FitzHugh–Nagumo equations. A numerical method is suggested that is based on techniques of feedback control. An error analysis is performed. Numerical examples confirm the theoretical predictions.

4

An information based approach to stochastic control problems

Bania Piotr

International Journal of Applied Mathematics and Computer Science

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2020

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Vol. 30, no. 1

23--34

EN

An information based method for solving stochastic control problems with partial observation is proposed. First, information-theoretic lower bounds of the cost function are analysed. It is shown, under rather weak assumptions, that reduction in the expected cost with closed-loop control compared with the best open-loop strategy is upper bounded by a non-decreasing function of mutual information between control variables and the state trajectory. On the basis of this result, an information based control (IBC) method is developed. The main idea of IBC consists in replacing the original control task by a sequence of control problems that are relatively easy to solve and such that information about the system state is actively generated. Two examples of the IBC operation are given. It is shown that the method is able to find an optimal solution without using dynamic programming at least in these examples. Hence the computational complexity of IBC is substantially smaller than that of dynamic programming, which is the main advantage of the proposed method.

5

Optimal control problems with a fixed terminal time in linear fractional-order systems

Gomoyunov M. I.

Archives of Control Sciences

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2020

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Vol. 30, No. 4

721--744

EN

The paper deals with an optimal control problem in a dynamical system described by a linear differential equation with the Caputo fractional derivative. The goal of control is to minimize a Bolza-type cost functional, which consists of two terms: the first one evaluates the state of the system at a fixed terminal time, and the second one is an integral evaluation of the control on the whole time interval. In order to solve this problem, we propose to reduce it to some auxiliary optimal control problem in a dynamical system described by a first-order ordinary differential equation. The reduction is based on the representation formula for solutions to linear fractional differential equations and is performed by some linear transformation, which is called the informational image of a position of the original system and can be treated as a special prediction of a motion of this system at the terminal time. A connection between the original and auxiliary problems is established for both open-loop and feedback (closed-loop) controls. The results obtained in the paper are illustrated by examples.

6

Bioprocess feedback control - a case study of the fed-batch biomass cultivation bioprocess

Ryniecki A., Wawrzyniak J., Gulewicz P., Horla D., Nowak D.

Przemysł Spożywczy

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2018

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T. 72, nr 8

34--39

EN

It is particularly difficult to control a biotechnological process because of significant sensitivity of living organisms cultured in bioreactors to process parameters and environmental conditions. Varying conditions of the process are also significant (a change in the chemical composition of the substrate or a change in the mass exchange conditions resulting from the modification of rheological parameters). The industrial biomass cultivation processes require the optimal biomass growth rate. In order to ensure it, it is necessary to analyze input variables, find the most representative output variables, and design an adequate automated control strategy, which should be tailored to a given bioprocess. The article analyzes selected automated control systems in fed-batch biomass cultivation bioprocesses presented in reference publications concerning bioprocess control. Open-loop and closed-loop control systems were taken into consideration. The research showed that open-loop control systems could not respond to process disturbances such as unexpected variations in input variables. Therefore, the authors analyzed closed-loop control systems in more detail, especially the feedback control systems with proportional-integral (PI) control action, which were used to stabilize the specific growth rate at a desired level. The authors presented equations which enable the online estimation of the specific growth rate on the basis of cellular metabolic heat. It has been noticed that the quality of automated control of bioprocesses can be further improved through improvement of control systems with a feedback.

PL

Kontrola przebiegu procesu biotechnologicznego jest szczególnie trudna ze względu na dużą wrażliwość hodowanych w bioreaktorach żywych organizmów – zarówno na parametry procesowe, jak i warunki środowiskowe. Nie bez znaczenia są również dynamicznie zmieniające się warunki prowadzenia procesu (zmiana składu chemicznego podłoża czy zmiana warunków wymiany masy jako efekt zmieniających się parametrów reologicznych). Procesy przemysłowej hodowli biomasy narzucają konieczność zapewnienia optymalnej szybkości wzrostu biomasy. Aby to zrealizować, niezbędne są: analiza wielkości wejściowych bioprocesu, znalezienie najbardziej reprezentatywnych wielkości wyjściowych oraz opracowanie odpowiedniej strategii sterowania automatycznego, która powinna być indywidualnie dobranado danego bioprocesu. W artykule poddano analizie wybrane systemy sterowania automatycznego procesem hodowli biomasy prowadzonej metodą okresową z zasilaniem – przedstawione w ostatnich latach w literaturze przedmiotu. Uwzględniono układy sterowania zarówno otwarte, jak i zamknięte. Stwierdzono, że sterowanie w układzie otwartym nie radzi sobie z zakłóceniami działającymi na bioprocess, takimi jak niespodziewane zmiany wartości wielkości wejściowych procesu. Dlatego autorzy z większą uwagą analizowali zamknięte układy sterowania, w szczególności te ze sprzężeniem zwrotnym wykorzystujące człon proporcjonalno-całkujący (PI), który posłużył do stabilizowania szybkości wzrostu biomasy na założonym poziomie. W pracy przedstawiono równania umożliwiające obliczanie on-line właściwej szybkości wzrostu biomasy na podstawie ciepła metabolizmu komórkowego. Zauważono, że możliwa jest dalsza poprawa jakości automatycznego sterowania bioprocesami poprzez doskonalenie systemów sterowania ze sprzężeniem zwrotnym.

7

Suboptimal control of nonlinear continuous-time locally positive systems using input-state linearization and SDRE approach

Bernat J., Kołota J., Stępień S., Superczyńska P.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

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Vol. 66, nr 1

17--21

EN

The infinite time suboptimal control problem for continuous-time nonlinear positive systems is formulated and solved. A solution to the problem using input-state linearization and state-dependent Riccati equation method (SDRE) is established, a procedure for solving the problem is proposed and illustrated with a numerical example.

8

Neuromechanical control in submaximal drop jumps: The effects of volitional effort demands and drop height magnitude on soleus muscle activation

Mrdakovic V., Pazin N., Vulovic R., Filipovic N., Ilic D.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 4

101--111

EN

The purpose of this study was to investigate soleus muscle activation during different phases of drop jump performed at submaximal levels of volitional effort and drop height magnitude. Methods: Fifteen professional volleyball players with minimum of eight years of experience in jumping activities participated in the study. Experimental protocol involved executing submaximal drop jumps at three levels of volitional effort (i.e., 65, 80 and 95% of the maximal height of jump). All submaximal drop jumps were done from three drop heights (20, 40 and 60 cm). The soleus muscle activation was monitored during four jump phases: pre-activation phase before touchdown, early contact phase upon touchdown, early and late push-off phase. Results: The results indicate that volitional effort level did not change the muscle activation during pre activation and early contact phase, but only in early and late push-off phase ( p ≤ 0.05). Conversely, it was observed that muscle activation during all phases of drop jump was adapted to the increased intensity of the external load caused by increasing of drop height magnitude ( p ≤ 0.01). Conclusions: The findings of the present study suggested that soleus muscle activation has selective responses to internal load (i.e., volitional effort level) and external load (i.e., drop height magnitude) intensities when drop jump is executing with submaximal effort.

9

Basic terms of process control: the on-off control system

Ryniecki A., Wawrzyniak J., Pilarska A. A.

Przemysł Spożywczy

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2015

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T. 69, nr 11

26--29

EN

This article explains the basic terms of process control: dynamic process as an object of control, process variable called also controlled variable, control (or manipulated) variable, control system, control with the feed-back loop as well as the principle of operation and quality indicators of the on-off control. To show indicators determining the quality of the on-off control, changes of process variable vs. time during this type of control were drawn. This was done based on: depicted static characteristic of a typical on-off controller, and parameters that characterize the dynamics of the object - a typical process of heat flow in a tank. Two parameters of the object (time-constant and time-delay) were drawn graphically using the step-response characteristic of the above mentioned thermal-process.

PL

Artykuł wyjaśnia takie pojęcia, jak: proces dynamiczny jako obiekt sterowania, wielkość regulowana (kontrolowana), wielkość sterująca, system sterowania, sterowanie ze sprzężeniem zwrotnym, jak również zasadę działania i wskaźniki jakości regulacji dwupołożeniowej. W celu przedstawienia wskaźników jakości regulacji dwupołożeniowej wykreślono zmiany wielkości regulowanej w tego typu regulacji. Dokonano tego na podstawie: przedstawionej charakterystyki statycznej typowego regulatora o działaniu dwupołożeniowym oraz parametrów, które charakteryzują dynamikę obiektu - typowego procesu przepływu ciepła w zbiorniku. Dwa parametry obiektu (stałą czasową i czas opóźnienia) wyznaczono graficznie przy użyciu charakterystyki skokowej wyżej wymienionego procesu cieplnego.

10

On suppression of chaotic motions of a portal frame structure under non-ideal loading using a magneto-rheological damper

Tusset A. M., Piccirillo V., Balthazar J. M., Brasil R. M. L. R. F.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 3

653--664

EN

We consider chaotic motions of a portal frame structure under non-ideal loading. To suppress this chaotic behavior, a controlling scheme is implemented. The control strategy involves application of two control signals and nonlinear feedforward control to maintain a desired periodic orbit, and state feedback control to bring the system trajectory into the desired periodic orbit. Additionally, the control strategy includes an active magneto-rheological damper to actuate the system. The control force of the damper is a function of the voltage applied in the coil of the damper that is based on the force given by the controller.

11

Stabilising feedback in Max-Plus linear models of discrete processes

Raszka J., Jamroż L.

Czasopismo Techniczne. Nauki Podstawowe

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2015

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Y. 112, iss. 1-NP

49--60

EN

This article relates to a synthesising output feedback that is used to control a network of discrete events. The feedback stabilises the system without reducing its initial throughput and its synthesis is mainly based on the theory of residues and the Kleene operator. This article suggests some theoretical results and mathematical foundations of max-plus algebra theory, and in particularly, discusses various other aspects of controlling discrete processes and their modelling in the context of a linear max-plus system.

PL

Artykuł dotyczy syntezy sprzężenia zwrotnego w sterowaniu siecią zdarzeń dyskretnych. Sprzężenie zwrotne służy do stabilizacji systemu bez zmniejszenia jego początkowej przepustowości i jego synteza opiera się głównie na wynikach teorii residuów i operatora Kleene’a. W artykule zasygnalizowano pewne wyniki teoretyczne i wprowadzono matematyczne podstawy max-plus algebry. Omówiono także inne aspekty sterowania procesami dyskretnymi oraz ich modelowanie w kategoriach liniowego systemu max-plus.

12

On attaining the prescribed quality of a controlled fourth order system

Kapustyan V., Maksimov V.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 1

75--85

EN

In this paper, we discuss a method of auxiliary controlled models and its application to solving some robust control problems for a system described by differential equations. As an illustration, a system of nonlinear differential equations of the fourth order is used. A solution algorithm, which is stable with respect to informational noise and computational errors, is presented. The algorithm is based on a combination of online state/input reconstruction and feedback control methods.

13

Control of Bending-Bending Coupled Vibrations of a rRotating Thin-Walled Composite Beam

Latalski J., Bocheński M., Warmiński J.

Archives of Acoustics

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2014

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Vol. 39, No. 4

605--613

EN

The paper presents a study of a possible application of structure embedded piezoelectric actuators to enhance the performance of a rotating composite beam exhibiting the coupled flexural-flexural vibrations. The discussed transversal and lateral bending modal coupling results from the directional properties of the beam’s laminate and ply stacking distribution. The mathematical model of the beam is based on an assumption of cross-sectional non-deformability and it incorporates a number of non-classical effects. The final 1-D governing equations of an active composite beam include both orthotropic properties of the laminate and transversely isotropic properties of piezoelectric layers. The system’s control capabilities resulting from embedded Macro Fiber Composite piezoelectric actuators are represented by the boundary bending moment. To enhance the dynamic properties of the composite specimen under consideration a combination of linear proportional control strategies has been used. Comparison studies have been performed, including the impact on modal coupling magnitude and cross-over frequency shift.

14

On dynamical identification of control in a system with time delay

Maksimov V.

Archives of Control Sciences

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2012

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Vol. 22, no. 1

5-15

EN

The problem of identification of a control through results of observations of phase states of dynamical systems described by differential equations with time delay is discussed. The paper presents an algorithm based on the method of feedback control with a model. The algorithm is stable with respect to informational noises and computational errors.

15

Stabilizacja systemów sterowanych

Mitkowski W.

Pomiary Automatyka Robotyka

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2011

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R. 15, nr 12

46-47

PL

W pracy przedstawiono kilka uwag na temat stabilizacji sterowanych układów dynamicznych. Wskazano różne obszary zastosowań praktycznych.

EN

The paper contains a remarks of the methods of stabilization of control systems. Examples of applications are presented.

16

Experimental characterization of hybrid noise control systeme acting in acoustic duct

Tiseo B., Concilio A., Ameduri S., Gianvito A.

Journal of Theoretical and Applied Mechanics

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2011

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Vol. 49 nr 2

313-326

EN

In this investigation, a sound absorbing material is coupled with an active surface to reduce sound pressure within an acoustic duct. In this way, an enhancement of the passive foam performance can be observed because of further acceleration of the fluid particles within the foam pores. The experimental activity implements noise control strategies to increase damping within the cavity through acoustic foam with a flexible backing plate, acted by piezoelectric actuators.

PL

W pracy zbadano skuteczność zastosowania materiału absorbującego dźwięk współpracującego z aktywną powierzchnią przeznaczoną do redukcji ciśnienia akustycznego w dukcie. Zaobserwowano, że takie skojarzenie znacznie poprawia pasywne właściwości samej dźwiękochłonnej pianki wskutek zwiększenia przyspieszeń cząstek płynu zawartego w porach pianki.Wwyniku badań doświadczalnych uzyskano strategie kontroli hałasu zwiększające tłumienie poprzez użycie akustycznej pianki na elastycznej płycie domykającej dukt i sterowanej elementami piezoelektrycznymi.

17

A stabilization method of inhomogeneous ladder networks with nonlinear elements

Skruch P.

Archives of Control Sciences

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2011

|

Vol. 21, no. 3

313-329

EN

In the paper, different structures of electric ladder networks are considered: RC, RL, and RLC. Such systems are composed of resistors, inductors and capacitors connected in series. The elements of the network are not identical and have nonlinear characteristics. The network's dynamic behavior can be mathematically described by nonlinear differential equations. A class of robust feedback controls is designed to stabilize the system. The asymptotic stability of the closed-loop system is analyzed and proved by the use of Lyapunov functionals and LaSalle's invariance principle. The results of computer simulations are included to verify theoretical analysis and mathematical formulation.

18

Simulation-based stability analysis of a thin-walled cylinder during turning with improvements using an adaptronic turning chisel

Fischer A., Eberhard P.

Archive of Mechanical Engineering

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2011

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Vol. LVIII, nr 4

367-391

EN

The dynamics of the turning process of a thin-walled cylinder in manufacturing is modeled using flexible multibody system theory. The obtained model is time varying due to workpiece rotation and tool feed and retarded, due to repeated cutting of the same surface. Instabilities can occur due to these consecutive cuts that must be avoided in practical application because of the detrimental effects on workpiece, tool and possibly the machine. Neglecting the small feed, the stability of the resulting periodic system with time-delay can be analyzed using the semi-discretization method. The use of an adaptronic tool holder comprising actuators and sensors to improve the dynamic stability is then investigated. Different control concepts, two collocated and two model-based, are implemented in simulation and tuned to increase the domain of stable cutting. Cutting of a moderately thin workpiece exhibits instabilities mainly due to tool vibration. In this case, the stability boundary can be significantly improved. When the instability is due to workpiece vibration, the collocated concepts fail completely. Model based concepts can still obtain some improvements, but are sensitive to modeling errors in the coupling of workpiece and tool.

PL

Dynamikę procesu toczenia przy obróbce cienkościennego walca zamodelowano stosując teorię giętkich układów wielu ciał. Uzyskano model uwzględniający zmienność w czasie wynikającą z obrotu przedmiotu obrabianego i posuwu narzędzia, a także opóźnienia powodowane wielokrotnym skrawaniem tej samej powierzchni. Niestabilności, które mogą powstać w wyniku tych wielokrotnych skrawań, powinny być wyeliminowane w praktycznych zastosowaniach, gdyż mają one szkodliwe skutki dla przedmiotu obrabianego, narzędzia, a nawet dla maszyny. Pomijając niewielki posuw narzędzia, wynikowa stabilność układu z opóźnieniem i zmiennego w czasie może być analizowana metodą częściowej dyskretyzacji. Badano zastosowanie uchwytu narzędziowego typu Adaptronic, zawierającego siłowniki i czujniki, którego zadaniem jest poprawa stabilności dynamicznej. W symulacji systemu wdrożono różne koncepcje sterowania, dwie kolokacyjne i jedną opartą na modelu, dobierając ustawienia tak, by zwiększyć zakres stabilnego skrawania. W procesie skrawania przedmiotu o umiarkowanie cienkich ścianach występują niestabilności spowodowane głównie wibracjami narzędzia. W tym przypadku granice obszaru stabilności mogą być znacznie poszerzone. Jeśli jednak niestabilność wynika z wibracji przedmiotu obrabianego, koncepcja kolokacyjna zawodzi całkowicie. Koncepcje oparte na modelu mogą nadal zapewniać pewną poprawę, lecz są wrażliwe na błędy modelowania zjawisk na styku przedmiotu obrabianego i narzędzia.

19

On one algorithm for solving the problem of source function reconstruction

Maksimov V.

International Journal of Applied Mathematics and Computer Science

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2010

|

Vol. 20, no 2

239-247

EN

In the paper, the problem of source function reconstruction in a differential equation of the parabolic type is investigated. Using the semigroup representation of trajectories of dynamical systems, we build a finite-step iterative procedure for solving this problem. The algorithm originates from the theory of closed-loop control (the method of extremal shift). At every step of the algorithm, the sum of a quality criterion and a linear penalty term is minimized. This procedure is robust to perturbations in problems data.

20

Feedback control of three-Level PWM rectifier: Application to the stabilization of DC Voltages of five-level NPC active power filter

Abdelkrim T., Berkouk E. M., Benslimane T., Benamrane K.

Archives of Control Sciences

|

2010

|

Vol. 20, no. 3

317-339

EN

One of the most important drawbacks of the three phases five-level NPC (Neutral Point Clamped) Active Power Filter (APF) is the neutral point balance. As the consequence, the capacitors voltages of the input DC bus of the APF are not equal which constitutes the major limitation for the use of this power converter. In order to stabilize these DC voltages, it is proposed in this paper to study the cascade constituted by three phases three-level PWM rectifier-clamping bridge filter-five-level NPC APF. In the first part, the authors present a topology of five-level NPC Voltage Source Inverter (VSI), and then, they propose a model of this converter and its PWM control strategy. In the second part, the modeling and control of three-level PWM current rectifier is presented. In the third part, to remedy to instability problem of the input capacitors DC voltages of the APF, the authors propose feedback control of the three-level PWM rectifier followed by clamping bridge filter. After that, the sliding mode regulator used to control the active filter is developed. The obtained results are full of promise to use this topology of APF in high voltage and high power applications.