Разработка алгоритмов и программного обеспечения для силовых активных фильтров судовых электроэнергетических систем

Based on the advantages of the passive filter and the active power filter, LC passive filter and active filter are combined to form a kind of parallel hybrid active power filter. But the harmonic circulation will produce between the active filter channel and the passive filter channel, which may cause active filter compensation part of the harmonic component into the passive filter and lead to the increase of total compensation capacity. This paper puts forward a new method for parallel hybrid active filter control in the above mentioned condition, and the new control method can effectively depart the passive filter compensation harmonic component, active filter compensation component and fundamental component. So it can give a clear division between the active filter and the passive filter, avoid harmonic circulation, and reduce active filter compensation capacity.

This paper discusses a technique of reducing harmonics in electric power grids using Shunt Hybrid Active Power Filter. The filter is controlled by a Model-Predictive Control technique. It can predict the output current magnitude based on its predictive model by noticing the constructed grid topology. Then, this current prediction has been compared to reference currents in order to get an optimal switching pattern concerning a cost function while the optimization has been conducted in order to figure out the maximum condition for the switching pattern. In addition, the Shunt Hybrid Active Power Filter has been compared by combining passive and active filters, which has been expected to be able to reduce harmonics optimally. The use of an LC filter in a single tuned has been also targetted in order to reduce the harmonics in the fifth-order, while the active filter would reduce harmonics due to their resonances. The constructed model has been tested in the simulation in order to evaluate how much harmonic reduction could be performed by the model, and how this model has coped with an unbalanced load, and later affecting the electric power quality. The simulation shows that Shunt Hybrid Active Power Filter along with the Model-Predictive Control method tested by non-linear loads, in terms of balanced and unbalanced loads, can reduce Total Harmonic Distortion of current loads to under 1%. As for unbalanced loads, the phase angle on source voltage does not encounter displacement. Therefore, the Model-Predictive Control on Shunt Hybrid Active Power Filter can effectively be used to reduce harmonics in the grid, during both balanced and unbalanced loading condition.

Nonlinear loads are essential part of power system. With the advancement in power electronics, switching elements have major share in electrical load. These elements create nonlinearities in lines increasing the line losses, reducing power quality and purity of sin wave. Passive filters work fine for harmonic elimination for specific frequencies which are considered in design specification. Active filters on the other hand work according to harmonics currently in line. Active filter designed in this work consists of a shunt active power filter that compensates current harmonic due to non-linear load. The active filter has a voltage source converter (VSC) which works in back to back configuration with a DC coupling capacitor. Power is injected by the VCS at the point of common coupling (PCC). The reference current is generated using instantaneous power theory. The harmonic components are separated from reference current, the reference is compared with actual current and the pulse width to control VSC is adjusted by the controller. The strength of proposed approach is illustrated through simulation in MATLAB software. The simulation results are then cross verified in real time using experimental setup. Total harmonic distortion (THD) of line current analyzed by fast Fourier transform (FFT) analysis is reduced to 4.56% from 28%.

This paper presents the design and simulation of a single-phase shunt active power filter for harmonic and power factor compensation of multiple nonlinear loads. The system is modeled in Matlab Simulink to consist of an uncontrolled rectifier and an AC controller as the nonlinear loads, with an active filter to compensate for the harmonic current injected by the load. The active filter is based on a full-bridge single-phase inverter. The design of the active filter controller is based on time-domain method that consists of three main tasks; to identify the harmonic content and form a synchronized reference, to provide closed-loop control to force the current of the active filter to follow the reference and to regulate the capacitor DC voltage. The spectral analysis of the supply current shows the harmonics produced by the load has been successfully compensated by the active filter. The effect of varying the switching frequency on the performance of the active filter is also presented.

<span>Four-leg active power filter is considered one of the greatest vital active filters that are frequently used in industrial applications, especially those that need to be controlled in each individual phase. Also, to control the neutral current that created because of a lot of unbalanced and non-linear loads. In this paper, the used active filter was controlled by a proposed control method which can achieve simplicity and intelligence at the same time. The novelty of this paper is using the proposed controller with Four-leg active power filter. This controller relies on instantaneous reactive power theory, which used to create the required currents that are injected into the network via the used active filter to remove the problems created by unbalanced and non-linear loads. It is also maintained that the current source a pure sinusoidal wave. The system is implemented on MATLAB/Simulink. The simulation results proved the preference of the proposed controller than the conventional proportional-integration controller, where it reduced the percentage of total harmonic distortion for the current source<em><span lang="AR-SA" dir="RTL">.</span></em></span>

This paper presents a new approach for harmonic control, and its practical implementation for a single-phase hybrid active power filter. It is a combination of a series active power filter and a shunt passive filter. The shunt passive filter is connected in parallel with a load and suppresses the harmonic current produced by the load, whereas the active filter connected in series to a source acts as a harmonic isolator between the source and load. For active filter control, sinusoidal pulse width modulation (SPWM) is developed and the modulation index is selected by calculating the DC bus voltage of the active filter. The PSpicereg, Matlab/Simulinkreg and MAX PLUS IIreg softwares are used for simulation and hardware implementation. ALTERAreg FLEX 10K controller and some peripheral circuits are used. Simulation and experimental results show that the proposed active power filter topology is capable of compensating the load current and voltage harmonic up-to the limit specified by IEC.

This paper presents diode clamped multilevel inverter as active power filter for elimination of harmonics current present in the nonlinear load. The power circuit of active power filter is comprised of three level DCMLI with DC bus capacitors. The active filter absorbs harmonics current of load and to inject reactive current requirement of the nonlinear load. Two different control schemes are tailored to estimate the tracking currents of the active power filters. The conventional least mean square (LMS) and adjustable step-size least mean square algorithms are presented for tracking current estimation. The modulation technique based level shift scheme with current regulator is used to track the firing signals for active power filter. The Matlab computer simulation study of active filter with nonlinear load is carried out. The adjustable step size algorithm exhibits improved performance characteristics for an active power filter.

This study begins with a brief overview of the problem of harmonic distortion and its effect on the quality of electric power, how the active power filter mitigate this problems then investigate the effect of control circuit time delay on the performance of Active Power Filter (APF). Active filter is an electronic power system that absorbs harmonic currents in the network, generated by nonlinear loads. The nonlinear load seems the main source of harmonic distortion in the power system. A shunt active power filter with optimized PI discussed in this study. Delay times are inevitable in Digital Signal Processing (DSP) based controllers can significantly degrade the performance of active power filter. Active filter performance can be affected by the delay between the control and measurement of the output current of SAPF and load current harmonics. The proposed filter reduces harmonic distortion is within an acceptable range.

The authors prepared a digital simulation program consisting of a passive filter, active filter, cycloconverter, and power supply system, and they studied a variety of combinations of passive and active filters in terms of harmonic compensation, parallel resonance suppression, and series resonance suppression. It is shown that the harmonic compensation equipment with a combined use of active and passive filters can effectively compensate a variable-frequency harmonic current generated by the cycloconverter over a wide operation range and can suppress the parallel and series resonance phenomena. The authors analyze the characteristics of three types of arrangement of the active and passive filters. The total harmonic current compensation and total current feedback compensation show good characteristics in terms of harmonic compensation and resonance suppression. >

Power quality problems have become the most important concern nowadays. Custom power devices (CPD) provide a solution for these power quality problems. There are various types of custom power devices. Out of these devices, harmonic filters are considered in this paper. Passive filter and active filter are combined to form shunt hybrid active power filter, (SHAPF). This paper proposes a hybrid device for power quality improvement. The device includes combination of shunt hybrid active power filter, thyristorised controlled reactor (TCR) and thyristorised switched capacitor (TSC). SHAPF consists of a shunt active power filter (SAPF) and a tuned passive filter. Passive filter is combined with TCR and TSC. This device reduces the harmonics and also compensates reactive power. A proportional integral (PI) controller is used to generate pulses for the switches of active power filter. Simulation results are compared for various conditions and are found to be satisfactory for reducing harmonic distortions and also for compensating reactive power.

The matrix converters are silicon based converters without bulky and expensive DC link capacitors other than its counterpart voltage source inverter (VSI) converters as an ideal voltage source and feed to ideal current source. Power electronic converters are a typical source of harmonic currents and during each switching cycle, the matrix converters produce unwanted harmonics and this will inject back to the AC mains. This harmonic current effect the overall operations of an AC supply. The main approach to the mitigation of this power quality problem is providing a filter in input side of the converter. Conventionally, passive filters with LC component were the choice for the elimination of harmonics and to improve power factor. These passive filters have the disadvantages such as large size, series and parallel resonance and fixed compensation. Active filters avoid the disadvantages of passive filters by using a switch mode power electronic converter to supply harmonic currents equal to those in the load currents. Active power filters can compensate both harmonic and reactive power simultaneously. In design of an active filter for matrix converter, a high displacement angle of input line current may compensated by matrix converter itself setting as reference for the input current a lagging displacement angle. It makes the reduced voltage transfer ratio for the system. So the control of the impedance interaction between the input filter and the voltage converter is mandatory. This paper propose a shunt active power filter for a 3x5 matrix converters to eliminate harmonic currents and to compensate reactive power for linear and non-linear loads. The paper presents the various design aspects of shunt active power filter for a 3x5 matrix converter. The control logic is made by using p-q theory and calculated the reference currents in order to compensate zero, harmonic and reactive currents (Fig. 1). To validate the proposed filter design, matlab simulation tests are conducted and results are presented. Simulations are carried out for the RL load and analysed the output with and without filter. These results shows less harmonic distortion in input current as well as reduced total harmonic distortion by using a simple active filter in input side. This proposed methodology has good results as compared with the conventional input filter. Fig. 2 presents simulation results of 3x5 matrix converter without any input filter. 80% of total harmonic distortion (THD) is reduced after accommodating an active input filter in to the same system (Fig.3).

Along the last years, the practical use of active filters to mitigate harmonics has been extended in electric power systems. Different configurations of series active filters versus shunt active filters have been proposed, among them, hybrid topologies which combine active and passive filters. Nevertheless, there is not any clear accordance about the most suitable configuration for each type of harmonic sources. In this paper, four different topologies of active power filters to eliminate harmonics have been analyzed. It has been implemented an experimental prototype corresponding to each configurations more used and they have been submitted to different performance tests. With this objective, a test bank has been developed, which includes voltage-source nonlinear loads, current-source nonlinear loads, and other whose behavior is between both. The analysis of experimental results obtained allows the most suitable active filter power topology to be determined for each type of load.

Non-linear load deteriorates the quality of current waveforms at the point of common coupling of various consumers. Active power filter (APFs) is used to mitigate the most concern harmonic pollution in an electrical network. The controller part is the nucleus of an active power filter configuration. Active power filter performance is affected significantly by the selection of current control techniques. The active filter and its current control must have the capability to track sudden slope variations in the current reference to compensate the distorted current drawn by the voltage source inverter. Therefore, the choice and implementation of the current regulator is more important for the achievement of a satisfactory performance level. In this survey, technical reviews of various types of controllers covering a wide range have been presented. This work also reveals the advantages and disadvantages of the practiced control strategies. The effectiveness of the study will help the researchers to choose the proper control methods for various applications of active power filter.

This paper presents the design of different topologies of active power filters to compensate reactive power and harmonics in the medium voltage level of a distribution power system. One pure active filter and two hybrid topologies, are implemented. A pure active compensation is obtained with a Shunt active power filter (SAPF). The shunt combination of SAPF and passive filter, form one of the hybrid topologies implemented, named shunt hybrid active power filter (SHAPF). The other hybrid topology, called hybrid shunt active power filter (HSAPF), connects the active filter in series with two shunt passive filters. Simulation for different load demands and distortions are performed. Finally a comparative evaluation of the different filters is carried out.

In modern power distribution systems, the majority of loads draw reactive power and/or harmonic currents from the AC source along with main active power currents. These nonunity power factor linear and nonlinear loads cause low efficiency of the power supply system, poor power factor, destruction of other equipment due to excessive stresses and EMI problems. Active filters have been considered an effective solution to reduce these problems. This paper presents an active power filter (APF) based on a simple control technique to provide reactive power and harmonics compensation for linear and nonlinear single-phase loads. A voltage source inverter with carrierless hysteresis PWM current control is used to form the APF. A simple PI DC bus voltage controller with a reduced energy storage capacitor is employed in the APF. A set of lagging/leading power factor linear loads and a diode rectifier-fed capacitive load and AC voltage regulator-fed inductive load as nonlinear loads are used to demonstrate the effectiveness of the proposed APF for reactive power and harmonic compensation. The detailed steady-state and dynamic performances of the APF are presented and discussed in brief.