Abstract— In this paper, a three-phase four-wire system connected a nonlinear load, dc/ac four leg voltage source converter to act as a four leg Active Power Filter (APF) using of instantaneouspower theory is presented. The use of a four-leg voltage- source inverter allows the compensation of current harmonic components, as well as unbalanced current generated by single- phase nonlinear loads. The instantaneouspower theory is applied to design the APF controller, which shows reliable performances. The MATLAB/SimpowerSystems tool has proved that the proposed control technique compensate the harmonic current drawn by nonlinear loads and controls the reactive power flow.
Instantaneouspower concept is utilized in determining the total real power consumed by the appliances/load. It is the most accurate method in calculating AC power. The result is always true in all kinds of loads; resistive, inductive, capacitive and even the modern harmonics-rich nonlinear DC loads. It is the product of instantaneous voltage and instantaneous current across an element. It is the power at any instant of time at which an element absorbs energy. Instantaneouspower consist of two parts which the first part is a constant or time dependent and the other part is a sinusoidal function which has twice the angular frequency of the voltage and current. The value of the time dependent part depends on the phase difference between voltage and current, which it is affected by the types of load connected to the system. The instantaneouspower is given by
Abstract - In the area of active power filtering, with an objective to reduce inverter capacity, the Series Hybrid Active Power Filter (SHAPF) has been taken into account increasingly. Existing method used for controlling SHAPF is either based on detecting source current harmonic or load voltage harmonics. Generalised InstantaneousPower Theory (GIPT) gives simple and direct method of defining power quantities under sinusoidal and non sinusoidal situations. The definition of GIPT is used to decompose voltage vector into different components, which represents different parts of the power quantity. The separated components of voltage vector are used to derive reference for SHAPF. This paper presents simulation study of SHAPF used for harmonic elimination, where the method used for calculating reference is based on GIPT. The mathematical formulation of proposed control scheme with its applications to SHAPF is presented. The validity of the proposed control scheme is verified by the simulation study.
line conditioners. The term "power conditioning" used in this book has much broader meaning than the term harmonic filtering." In other words, the power conditioning is not confined to harmonic filtering, but contains harmonic damping, harmonic isolation, harmonic termination, reactive-power control for power factor correction, power flow control, and voltage regulation, load balancing, voltage-flicker Suction, and/or their combinations. Active power line conditioners are based on leading-edge power electronics technology that includes power conversion circuits, power semiconductor devices, analog/digital signal processing, voltage/current sensors, and control theory. Concepts and evolution of electric power theory are briefly described below. Then, the need for a consistent set of power definitions is emphasized to deal with electric systems under non-sinusoidal conditions. Problems with harmonic pollution in alternating current systems (ac systems) are classified, including a list of the principal harmonic-producing loads. Basic principles of harmonic compensation are introduced. Finally, this chapter describes the fundaments of power flow control. All these topics are the subjects of scope, and will be discussed deeply in the following chapters of the book. The instantaneouspower theory, or ―the p-q theory,‖ makes clear the physical meaning of what instantaneous real and imaginary power is in a three-phase circuit. Moreover, it provides insight into how energy flows from a source to a load, or circulates between phases, in a three- phase circuit. This theory can be used in the design and understanding of FACTS (Flexible AC Transmission System) compensators. The book introduces many concepts in the field of active filtering that are unique to this edition. It provides a study tool for final year undergraduate students, graduate students and engineers dealing i-th harmonic pollution problems, reactive power compensation or power quality in general. 2 EXISTING SYSTEM
In this paper, a simplified instantaneouspower control is proposed to suppress the 2h DC bus voltage under generic unbalance conditions without any sequential component decomposers. Firstly, the proposed method does not require any P- and N-sequence decomposers to extract the P- and N-sequence output voltages, which are obtained directly from the outputs of the current PI-R controllers. Secondly, unlike the model-based estimation method [4, 16] to estimate the P- and N-sequence output voltages, which is sensitive to the parameters, the proposed method is robust to generalized unbalance conditions even when the line impedances are unbalanced. The feasibility of the proposed method is verified on a small-scale three-phase permanent magnet synchronous generator (PMSG) with inherent asymmetry. In addition, the method is tested on the prototype system when different external asymmetries were introduced deliberately in the line impendences.
Power delivery to the load point is expected to be utmost clear in nature with accuracy. Any deviation of power network parameters from the ideal form is annoyance in power system [1-5]. Poor power quality  makes system to experience stalled production, increased energy consumption, reduction in production pace, malfunctioning of equipment, reduced efficiency, reduction in life time of equipment. Presence of non- linear loads deteriorates power quality by inducing harmonics in source components. Harmonics are the waveforms having frequencies which are integral multiples of fundamental frequency. Non-linear loads when connected draw only non- linear components of currents from source components leaving out harmonic components at point of common coupling (PCC) [1-4]. This phenomenon disturbs or distorts the source currents and affects the other sensitive loads connected at PCC. Harmonic mitigation can be done through many ways. Passive filters with low circuit arrangement can mitigate harmonics. But passive filters can fix only fixed harmonics for which the particular passive filter is tuned leaving out remaining harmonics in the system. Also as order of harmonics is low, size of the passive filter increases as passive filter parameters are inversely proportional to tuned frequency [5-7]. This led to development of FACTS based devices for power quality improvement. DSTATCOM is one among FACTS controllers to improve power quality.
This paper describes a three-phase shunt active power filter using a conventional three leg IGBT converter, without the need of power supply at DC bus. Two approaches have been discussed in this paper to control the active power filter. The first approach discussed is voltage source instantaneouspower control technique and the second is carrier-based control technique. Simulation results from a complete model of shunt active power filter are presented to validate and compare the control strategies.
package to estimate the instantaneouspower density along the river reach in the whole region. Meteorological data needed for the simulation was obtained from the Lower Niger River Basin Development Authority and the World Meteorological Organisation database. Table 1 presents the hydraulic parameters of the river sites while Figure10 shows the power along the sub basins.
ABSTRACT: The main aim of this paper is to compensate current harmonics in PV-APF system using Fuzzy Logic Controller. A 3-Ф, 3-wire system is proposed in this paper which consists of PV system, a dc/dc converter which is controlled by MPPT, three phase VSC to act as APF and Non-Linear Load. The main theme of this INC MPPT is to efficiency from the PV system. For reliable performance of active power filter and better harmonic compensation this paper proposes a concept of instantaneouspower theory. Also, a comparison analysis is performed for improving THD by PI/Fuzzy controllers. This system is experimentally verified and tested using Simulink.
This work proposes a compensation scheme that provides simultaneous correction of harmonic content and load unbalance for railroad systems using an open delta connection in the power substation. This method is based on the instantaneouspower description of the scheme, using space vector representation of the state variables, and the use of direct power control (DPC) to attain the required correction by minimizing a cost function achieved from the instantaneous active and reactive mismatch .The control strategies presented in this work are experimentally legalized using a DSP based modular power electronic system able to emulate the electric traction system operating conditions, the open delta transformer and the filtering and load balancing converters .
Considering the variations we observed in instantaneouspower measurements, we were surprised by the absence of more significant differences in the profiles obtained by our energy-driven sampler and our PowerScope prototype. For example, Figure 6 shows instantaneous current readings obtained by sampling at three different frequencies (100 Hz, 800Hz, and 12.5 KHz) during the mpeg benchmark. Recall that the PowerScope ap- proach assumes that the instantaneouspower consumption associated with each sample approximates average power consumption since the prior sample. Comparing each sample value at 100 or 800 Hz with the average across 12.5 KHz sample values since the prior 100 or 800 Hz sample reveals more than a few instances in which this assump- tion does not hold. This observation suggests that the profile generated by the Power- Scope approach could contain substantial inaccuracies, a hypothesis that explains the approach' s over-attribution of energy to the kernel-idle loop. Interestingly, however, when the samples attributed to this loop are ignored (Figure 5), the profiles generated by the two approaches do not differ substantially.
In addition to possessing cold-adapted muscle, morphological features also contribute greatly to the ability of O. bruceata moths to fly over a broad range of body temperatures, down to or even slightly below 0 ˚C. This can be demonstrated by combining morphological (Table 1) and muscle power output data (Fig. 3C) from O. bruceata and M. sexta moths in order to estimate the range of temperatures over which they have sufficient muscle power output for flight. Maximum instantaneouspower output as measured in this study is about half of the continuous power output that a muscle achieves during normal cycles of contraction and relaxation (Josephson, 1993; R. D. Stevenson, personal communication). Furthermore, approximately half of the
This control strategy is used for the generation of reference source currents [6-7]. Inputs of the Instantaneous active and reactive power theory (p–q theory) are load side harmonic currents, source voltages and loss component current from the dc link voltage control. The concept of instantaneous reactive power theory (p-q theory) method basically consists of a variable transformation from the a, b, c reference frame of the instantaneouspower, voltage and current signals to the α − β reference frame . The conversion formulae of voltages and currents are given below
This paper, propose a Three-terminal Reduced DC Bus Capacitance Unified Power Flow Controller (UPFC) for Low Voltage (LV) distribution Networks with High Photovoltaic (PV) penetrations. The device is shown capable of voltage regulating and correcting phase unbalance voltages that can be produced by high levels of distributed photovoltaic (PV) generation. The device is also capable of Power factor improvement (PFI) and correction, regulating the zero, positive and negative sequence voltage in LV distribution Networks and neutral or zero sequence current compensation. Instantaneous reactive power theory shows The power of DC Bus capacitor will fluctuate at twice mains frequency during unbalanced operation. The Real and Instantaneouspower balance of Unified Power Flow Controller (UPFC) can be maintained by allowing the shunt input converter to draw a small negative and positive sequence current. The InstantaneousPower balance with negative sequence current allows a hundred-fold reduction in the value of DC bus capacitance which allows long life polypropylene or ceramic capacitors to replace of electrolytic capacitor in this application.
The effectiveness of active power filter depends on accurate extraction of fundamental component of current waveform and fastness of control strategy. The SAPF consists of a DC-bus capacitor, power electronic devices and coupling inductors (L). Shunt APF acts as a current source for compensating the harmonic currents due to nonlinear loads. SAPF draws current in such a way that the source current which is sum of load current and active filter current becomes sinusoidal i.e.
ABSTRACT: The power quality issues are becoming more severe and point of concern in many studies. Non linear loads in industries produce harmonic currents which are then injected in supply system. It creates some power quality issues. Shunt Active Power Filter (SAPF) is widely to reduce these power quality issues. SAPF can improve voltage profile, harmonics can be reduced and power factor is also improved. Great reduction in total harmonic distortion is seen while using SAPF. Reference current generation is the key factor of Active power filter. Reference current generation and hence controlling SAPF using instantaneous reactive power (IRP) theory is explained and presented in this paper. Instantaneous reactive power theory is effectively used to generate reference currents and to control Active Power Filters (APF).MATLAB/simulinkis used for modeling of this technique.
Abstract: For wideband or high power applications, the power amplifier exhibits memory effects, for which memoryless predistorters can achieve only limited linearization performance. The memory polynomial predistorter can correct both the nonlinear distortions and the linear frequency response that may exist in the power amplifier. It is a robust predistorter, which has demonstrated good performance on several nonlinear system models. The predistorter models considered in this paper include both even- and odd order nonlinear terms. Here, the benefits to include even-order nonlinear terms in both the baseband power amplifier and predistorter models are described.
Abstract: this paper presents the primary objective of a research project which aims at enhancing the world of e-mobility by highlighting the continuous evolution and demand of the Electric Vehicle (EV) in modern cities and the consequent need for more and more innovative charging systems. Here we focused on a current and incoming EV drawback, namely the variety of EV charging methods which are currently available in the market. An adaptive solution, which is suitable for both domestic and working environments, is presented, where single-phase recharging points are applied with non-high power. The task is to provide a user-friendly support for any end-user who wants to acquaintance with the EV world. Three stages are characterizing this approach: (1) the search for new solutions for the charging of electric vehicles, (2) the finalization and achievement of the proof of concept and product, (3) a set of functional tests (i.e. the validation). The proposed product is preserved from electric blackout during the EV recharging phase within a typical daily life domestic activity: this result is achieved through a combination of smart devices, an intelligent framework and the charging point. An optimized calculation program supervises this architecture and it allows the real-time interaction and communication between all the components by carrying out a dynamic control of the loads.
A novel tri-window based compensator for the compensation of loads with a non- periodic current was proposed. This compensator consists of three co-located devices with different calculation window, called fast compensator, reactive compensator, and slow compensator. By decomposing the load current into mathematically non- orthogonal non-synchronized components, different frequency ranges of the current waveform are addressed separately. This optimizes the design of active filters, by choosing devices with lower power rating and higher switching frequency, and de- vices with higher power rating and lower switching frequency. Moreover, separating the reactive current component of the load current allows utilizing the Static Var Compensators (SVCs) which lowers the overall cost of the design. Adding an adap- tive fuzzy algorithm, whose rules are based on the characteristics of the non-periodic loads, results in optimizing the window length of the slow compensator and decreas- ing bandwidth and reaction time of the compensator to transients.
The international standards recommend calculating the spatial-peak pulse-averaged intensity from free-field measure- ments made using a hydrophone . Damage thresholds and bandwidth limitations of regular hydrophones along with propagation nonlinearities  make measurement of these fields at clinically relevant intensities impossible. Therefore, for regular hydrophones, the recommendation is to take mea- surements under quasi-linear conditions and scale them with drive voltage to predict intensity values at higher powers . Several authors have suggested using fibre optic hydrophones instead, which have much higher damage thresholds and can therefore be used to measure the subtle variances in intensity due to nonlinear propagation , . Measurements using hydrophones must be performed at low duty cycles. For higher intensities and duty cycles, the radiation force balance (RFB) is the gold standard. It provides total acoustic power and spatial-average intensity if the beam dimensions are known . However, both hydrophone and RFB measurement must be made in the free field before an exposure and can make no guarantees for patient safety during therapy. Therefore, a technique that can monitor power delivery during a HIFU exposure is highly desirable.