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Power supply with parallel reactive and distortion power compensation and tunable inductive filter – Part 1
... In the first part of the paper [1], the idea of the DC power supply (PSP) with the ability of active compensation of both reactive and distortion power was proposed. Moreover, thanks to extending the "frequency response" of the power electronics current source, which is a crucial part of the PSP, the quality of the compensation process was more efficient, compared to most of the typical solutions of active filters. ...
... The general concept of power supply, based on the current source with the tunable inductive filter, was presented in the first part of the paper [1]. Therefore, only a brief description of the system structure and the basics of its operation is given here, for the reader's convenience. ...
... The value of the equivalent reactance (X TI ) of the filter, seen from the power source side, reaches two values [1]: ...
... The current work forms part of a research project on DC power supplies with both a power factor correction (PFC) and a shunt active power filter (SAPF) function, based on a tuneable magnetic device [1,2]. ...
... The concept of a DC power supply, operating with PFC and a SAPF function, equipped with a tuneable inductive filter, was presented in previous work [1] and only a brief explanation of the structure of a PSP and the rules of its operation is given in this section for the reader's convenience. ...
... The inductive filter increases the value of the input impedance of the current source and minimises the magnitude of the PSP input current, associated with the pulse modulation carrier signal (PWM here), which is used to control the VSI [17]. Taking into account the linear model of the VCCS [1,17] it is assumed that during the given half-periods of the line voltage waveform the appropriate pairs of transistors (T1-T4 or T3-T2) are turned on. The VCCS input current waveform is then described by the following general formula (However, it does not include: the inductive filter resistance, power line impedance, and voltage drops at the switches in the VSI.): ...
... This was carried out based on a tuned inductive filter (TI), which representing a new approach to such power electronics devices. As a result, the quality of the compensation process is better, e.g., the nonlinear distortions of the grid current are lower, than in the typical solution of a parallel active filter [4], as indicated by the results of simulation [23] and laboratory tests of the power supply (PSP). ...
... The ability of the VCCS to appropriately shape the input current is mainly determined by the frequency response, taking into account the linear model of this device. This model was analysed in previous works [23,25]. ...
... Respecting the impact of the operation of the RSC block on the stability of the PSP (based on the linear model of this device [23]), the REGA block was implemented as a first-order low-pass filter. In this case, Equation (9) takes the form: ...
This work focuses on the use of a one-phase direct current (DC) power supply equipped with a shunt active filter feature, which enabled the possibility of compensation (minimisation) of reactive and distortion power, generated by a group of loads, that was connected to the same power grid node as the power supply. A tuned inductor, which was included at the input of the controlled current source (constituting the main part of the power supply) allowed for an improvement in the quality of the compensation process, compared to a device with a fixed inductive filter This resulted in a visible reduction of the nonlinear distortions of the grid current. The improvement was made possible by extending the frequency response of the current source, which allowed to increase the dynamics of the current changes at the input of the power supply. This solution represents a new approach to such power devices. This work describes the principle of operation of the proposed converter solution and presents selected test results for a laboratory model of an electric system with this device.
... • parallel active power filters, e.g., [23]. • power supplies with the PFC function [24,25]. • converters, cooperating with the power grid, which were applied in a photovoltaic power plant with a distributed solar panel system [26]. ...
... This board, among others, is equipped with a multi-channel precision AD converter with simultaneous sampling capability and TRUE-BIPOLAR type inputs, as well as a multi-channel DA converter with outputs that are also of a TRUE-BIPOLAR type. This system is intended for use in advanced measurement applications as well as for the implementation of complex control algorithms of power electronics devices, e.g., [23][24][25][26]. Potentially, it offers significant computational power, up to 2400 MFLOPS (million-floating-point operations-per-second), if the math units operate in a single-instruction-multiple-data (SIMD) mode [31]. ...
... The ADSP-213xx family of DSP supports SIMD operations, which, under certain conditions, double the computational rate This board, among others, is equipped with a multi-channel precision AD converter with simultaneous sampling capability and TRUE-BIPOLAR type inputs, as well as a multi-channel DA converter with outputs that are also of a TRUE-BIPOLAR type. This system is intended for use in advanced measurement applications as well as for the implementation of complex control algorithms of power electronics devices, e.g., [23][24][25][26]. Potentially, it offers significant computational power, up to 2400 MFLOPS (million-floatingpoint operations-per-second), if the math units operate in a single-instruction-multiple-data (SIMD) mode [31]. ...
Calculating the values of the parameters of distorted periodic signals in real-time is important for the control of many processes. In particular, this information is necessary for the proper operation of power electronics devices that cooperate with the power grid. In such cases, it is necessary to determine the phase, frequency, and amplitude of the fundamental component of the voltage in the power grid node. Also, in many cases, the control process needs a signal which is synchronised with the power grid voltage. Both processes should be realised in real-time. A number of solutions to the problem of calculating the values of the voltage parameters have been described in the literature. However, these methods generally introduce significant time delays and have several restrictions regarding the variability in the values of these parameters. They also often require the significant computational power of a unit that performs the task of identification. The algorithm presented in this work is based on the properties of a pair of orthogonal signals, generated by a two-dimensional finite impulse response filter, which has a certain transfer function resulting from the needs of the algorithm, what is the innovation of the algorithm. These signals are then used in the program module, which both, calculates, in the time domain, the instantaneous values of the frequency and the amplitude of the fundamental component of the power grid voltage, and generates a signal, being in-phase with this component. The presented algorithm is fast, accurate, and relatively simple; therefore, it does not require a high computational power processor. This algorithm was experimentally verified by implementation in microcomputer-based units, which were then applied in the control systems of the power electronic devices, as well as in analysers of the energy quality.
... Several classical techniques [1] have been implemented for solving ORPD problem. The difficulties of the conventional optimization approaches (COA) arise when we incorporate system constraints, trapped in local minima. ...
The result of continuous efforts in the development of power theory, Budeanu’s power theory was successfully extended. The mathematical description that has been proposed is based on another concept, namely the Currents’ Physical Components (CPC) theory. With CPC theory, it was possible to describe, in the original Budeanu theory, the components of the load current, including the Budeanu distortion current. The Budeanu distortion current can have a maximum of five components associated with different physical phenomena and related to the equivalent parameters of the load. This article discusses passive compensation, which provides compensation for the Budeanu reactive current and the Budeanu complemented reactive current due to the known equivalent load parameters associated with the reactance elements. In addition, the article refers to a very important aspect when determining the parameters of a passive compensator, i.e., choosing parameters in such a way that the compensator simultaneously compensates for the reactive current and the unbalanced current. The article presents five methods relating to the determination of compensator parameters. Two methods are related to the reactive current compensation only for the first harmonic without affecting the unbalanced current. The next three methods relate to the compensation of the Budeanu reactive current and the consideration of the unbalanced current. Calculations and simulations were performed for all five methods, the results of which are presented and analyzed in this publication. The Matlab/Simulink R2023a environment was used as the calculation and simulation software.
This paper presents the resolution of the optimal reactive power dispatch (ORPD) problem and the control of voltages in an electrical energy system by using a hybrid algorithm based on the particle swarm optimization (PSO) method and interior point method (IPM). The IPM is based on the logarithmic barrier (LB-IPM) technique while respecting the non-linear equality and inequality constraints. The particle swarm optimization-logarithmic barrier-interior point method (PSO-LB-IPM) is used to adjust the control variables, namely the reactive powers, the generator voltages and the load controllers of the transformers, in order to ensure convergence towards a better solution with the probability of reaching the global optimum. The proposed method was first tested and validated on a two-variable mathematical function using MATLAB as a calculation and execution tool, and then it is applied to the ORPD problem to minimize the total active losses in an electrical energy network. To validate the method a test was carried out on the IEEE electrical energy network of 57 buses.
The paper presents the control system and selected results of experimental tests of the AC/DC power converter consisting of an 18-pulse diode rectifier based on coupled reactors and a serial active power filter. Proportional integral controllers with decoupling components are implemented in multiple reference frames for selective line current harmonic suppression. The regulator is provided with a backtracking anti-windup mechanism of sorts in which a signal proportional to the saturated control reference is subtracted from the error signal in each reference frame. The fundamental harmonic filter based on the DFT algorithm with phase correction is used for grid synchronization and current harmonic detection. Three configurations of the 15 kVA converter were tested experimentally and then compared: the 18-pulse diode rectifier with and without an additional grid reactor, and the rectifier integrated with an active power filter. The applied control method of active filter significantly reduces harmonic distortion and unbalance of the grid current, which is particularly advantageous under non-ideal supply voltage and low loads conditions.
The paper includes a summary and a background of long-time research conducted by a research team in the Institute of Electrical Engineering and Computer Science at Silesian University of Technology. The research work has principally been related to selected problems in the field of analysis and synthesis of systems aimed at symmetrisation and improvement of some power quality parameters. This paper constitutes a first part of the report on the research. It has been devoted to effective elimination of higher harmonics and reactive power compensation by means of parallel active power filters. The other problem discussed in this paper is related to this issue and it is very important from the economic point of view; it addresses optimal sizing and placement of active power filters in investigated power networks.
This paper presents model predictive control (MPC) with a finite control states set (FS) for three-level four-leg flying capacitor (FCC) converter. Principles of control method are presented and flying capacitor voltages control method is discussed. Experimental results of converter operating as a shunt active power filter (SAPF) and grid connected inverter (GCI) are shown.
Evaluation of the Shunt Active Power Filter apparent power ratio using particle swarm optimization
The main objective of this present paper is the study of the Shunt Active Power Filter (APF) compensations capability for different perturbations in AC power system such as current unbalance, phase shift current and undesired harmonics generated by nonlinear load and/or by the power system voltage. This capability is determined by the maximum rate of the apparent power that can be delivered. This study is based on the definition of the effective apparent power as defined in IEEE 1459-2000 which was proved to be the suitable amount to be concerned in the design process of different devices.
Reactive compensator synthesis in time-domain
The source reactive-current compensation is crucial in the energy transmission efficiency. The compensator design in a frequency-domain has already been widely discussed and examined. This paper presents results of a study on how to design reactive compensators in a time-domain. It is the first time the reactive compensator has been designed in a time domain. The example of a compensator is presented.
The considered shunt active power filter can be controlled not only to compensate non-active current in the supply source, but additionally to optimize energy flow between the source and the load. In such a case the filter shapes the source current to be active and simultaneously regulates its magnitude. The presented filter/buffer can operate properly even when the load contains AC or DC variable energy source of any characteristic. The device can optimize energy flow for a single load, but also for a group of loads as well. The distinctive feature of the employed control method of the filter/buffer is that certain changes of energy stored in the device are utilized as the source of information concerning the active current of the load. This control method is very flexible and can be implemented to nearly all structures of active filters, for DC, single- and multiphase circuits.
In this paper, a systematic review of bridgeless power factor correction (PFC) boost rectifiers, also called dual boost PFC rectifiers, is presented. Performance comparison between the conventional PFC boost rectifier and a representative member of the bridgeless PFC boost rectifier family is performed. Loss analysis and experimental efficiency evaluation for both CCM and DCM/CCM boundary operations are provided.
This comprehensive handbook is a one-stop engineering reference. Covering data converter fundamentals, techniques, applications, and beginning with the basic theoretical elements necessary for a complete understanding of data converters, this reference covers all the latest advances in the field. This text describes in depth the theory behind and the practical design of data conversion circuits as well as describing the different architectures used in A/D and D/A converters. Details are provided on the design of high-speed ADCs, high accuracy DACs and ADCs, and sample-and-hold amplifiers. Also, this reference covers voltage sources and current reference, noise-shaping coding, and sigma-delta converters, and much more. The book's 900-plus pages are packed with design information and application circuits, including guidelines on selecting the most suitable converters for particular applications. You'll find the very latest information on: Data converter fundamentals, such as key specifications, noise, sampling, and testing Architectures and processes, including SAR, flash, pipelined, folding, and more Practical hardware design techniques for mixed-signal systems, such as driving ADCs, buffering DAC outputs, sampling clocks, layout, interfacing, support circuits, and tools. Data converter applications dealing with precision measurement, data acquisition, audio, display, DDS, software radio and many more. The accompanying CD-ROM provides software tools for testing and analyzing data converters as well as a searchable pdf version of the text. * Brings together a huge amount of information impossible to locate elsewhere. * Many recent advances in converter technology simply aren't covered in any other book. * A must-have design reference for any electronics design engineer or technician.
Power electronics, which is a rapidly growing area in terms of research and applications, uses modern electronics technology to convert electric power from one form to another, such as ac-dc, dc-dc, dc-ac, and ac-ac with a variable output magnitude and frequency. Power electronics has many applications in our every day life such as air-conditioners, electric cars, sub-way trains, motor drives, renewable energy sources and power supplies for computers. This book covers all aspects of switching devices, converter circuit topologies, control techniques, analytical methods and some examples of their applications.
The paper presents models of the active power filter based on the of voltage source converter structure. For the single-phase circuit two models are presented - transformer model with varying turns-ratio and time-varying capacitance model. The models are results of current and voltage averaging. The relation between two models is formulated. The numerical examples illustrate time-varying parameters of considered models.
Modeling of the AC/HF/DC converter with power factor correction
In this paper, the power factor correction system consisted of: bridge converter, parallel resonant circuit, high frequency transformer, diode rectifier and L F C F filter is presented. This system is controlled by a pulse density modulation method and the principle of its operation is based on the boost technique. The modeling approach is illustrated by an example using AC/HF/DC converter. Verification of the derived model is provided, which demonstrated the validity of the proposed approach.
Purpose
The aim of the research was to find a structure of the power electronics controlled current source with extended pass band, which would better match a source output current within an input (reference) signal. Also, pulse modulation components in output current of current source should be minimized.
Design/methodology/approach
The power electronics controlled current source utilizes both, the concept of the inductor with variable (controlled) inductance located at the output of an inverter and the concept of the multi‐channel (interleaved) inverter. The small signal (linear) and simulation models of an active filter have been investigated.
Findings
The work presents the concept of 1‐phase active shunt filter with utilization of the power electronics current source about extended pass‐band.
Research limitations/implications
The research should be continued to achieve stability of the electrical system with variable parameters of the power network and receiver.
Practical implications
The research will be continued towards realization of a laboratory model of a 3‐phase active shunt filter with the DSP based control module.
Social implications
Social implications are difficult to determine.
Originality/value
The paper presents a new concept of the precision power electronics controlled current source with the extended pass‐band. The controlled current source is the fundamental block of a power electronics active shunt filter.
An interleaved boundary conduction mode power-factor-correction buck converter that maintains high efficiency across entire load and line range is proposed. The adaptive master-slave interleaving method maintains stable 180° out-of-phase operation during any transient. By interleaving two parallel-connected buck converters, the input current ripple is halved while the ripple frequency is doubled, which leads to a smaller differential mode line filter. The line current harmonic distortion is analyzed to examine the allowable output voltage range while meeting harmonic regulations. The operation and performance of the proposed circuit is verified on a 300 W, universal line experimental prototype with 80 V output. The measured efficiencies remain above 96% down to 20% of full load across the entire universal line range. Even at 10% of full-load condition, the efficiency remains above 94%. The input current harmonics also meet the IEC61000-3-2 (class D) standard.
An improved buck power factor correction (PFC) converter topology is proposed in this paper. By adding an auxiliary switch and two diodes, the dead zones in ac input current of traditional buck PFC converter can be eliminated. An improved constant ON-time control is proposed and utilized in this improved buck PFC converter to force it that operates in critical conduction mode (CRM). With optimal control parameters, nearly unit power factor can be achieved and the input current harmonics can meet the IEC61000-3-2 class C standard within the universal input voltage range. Moreover, the efficiency of the proposed converter is not deteriorated compared to the conventional buck converter. Detailed theoretical analysis and optimal design considerations for the proposed converter are presented and verified by a 100-W lab-made prototype.
Different power theories are examined, with regard to their applicability in controlling dynamic filters for non-active power. Frequency-domain approaches and a range of time-domain approaches are considered, the latter being inherently more suitable for real-time control of dynamic filters. Finally, some detailed attention is devoted to a combination of the approaches by Fryze, Buchholz and Depenbrock. This FBD-approach leads to a general time-domain resolution of power components in a generalized m-wire system that can be used effectively in deriving control algorithms for dynamic filters of non-active power.
In this paper a novel representation of transfer functions of sampled-data systems in the lifted domain is proposed. The main idea is to express these transfer functions by the STPBC (systems with two-point boundary conditions) machinery avoiding the appeal to the state space in the lifted domain. This produces a compact LTI description of sampled-data systems in which the intersample dynamics are driven solely by the open-loop dynamics of continuous-time parts of the system and discrete-time dynamics shows up through a reshaping of the boundary conditions. The proposed representation simplifies manipulations over sampled-data systems and enables one to keep track of their structure under multi-level algebraic manipulations.
In this paper, a new bridgeless single-ended primary inductance converter power-factor-correction rectifier is introduced. The proposed circuit provides lower conduction losses with reduced components simultaneously. In conventional PFC converters (continuous-conduction-mode boost converter), a voltage loop and a current loop are required for PFC. In the proposed converter, the control circuit is simplified, and no current loop is required while the converter operates in discontinuous conduction mode. Theoretical analysis and simulation results are provided to explain circuit operation. A prototype of the proposed converter is realized, and the results are presented. The measured efficiency shows 1% improvement in comparison to conventional SEPIC rectifier.
The operation of switch-mode converters results in electromagnetic noise propagating throughout the power electronic system. Pulsewidth modulation (PWM) strategies with fixed switching frequency generate harmonics in the spectra of converter voltages and currents. Random PWM techniques allow the elimination of the harmonics, resulting in a continuous spectrum of noise, i.e., a spectrum retaining all frequency components. As a next step in advanced spectral shaping, a method presented in this paper produces spectral nulls at selected frequencies. This allows the carving of communication channels in the noise and the removal of spectral power at frequencies potentially harmful for the system. The theoretical analysis, computer simulations, implementation details, and experimental results are presented.
With the increasing use of distributed energy (DE) systems in industry and its technological advancement, it is becoming more important to understand the integration of these systems with the electric power systems. New markets and benefits for DE applications include the ability to provide ancillary services, improve energy efficiency, enhance power system reliability, and allow customer choice. Advanced power electronic (PE) interfaces will allow DE systems to provide increased functionality through improved power quality and voltage/volt-ampere reactive (VAR) support, increase electrical system compatibility by reducing the fault contributions, and flexibility in operations with various other DE sources, while reducing overall interconnection costs. This paper will examine the system integration issues associated with DE systems and show the benefits of using PE interfaces for such applications.
In this paper, model reference adaptive control (MRAC) is proposed for a single-phase shunt active power filter (APF) to improve line power factor and to reduce line current harmonics. The proposed APF controller forces the supply current to be sinusoidal, with low current harmonics, and to be in phase with the line voltage. The advantages of using MRAC over conventional proportional-integral control are its flexibility, adaptability, and robustness; moreover, MRAC can self-tune the controller gains to assure system stability. Since the APF is a bilinear system, it is hard to design the controller. This paper will solve the stability problem when a linearization method is used to solve the nonlinearity of the system. Moreover, by using Lyapunov's stability theory and Barbalat's lemma, an adaptive law is designed to guarantee an asymptotic output tracking of the system. To verify the proposed APF system, a digital signal controller (dsPIC30F4012) is adopted to implement the algorithm of MRAC, and a 1-kVA laboratory prototype is built to test feasibility. Experimental results are provided to verify the performance of the proposed APF system.
The control of a linear time-invariant plant by a digital
controller composed of a sampler, a periodic discrete-time component,
and a zero-order hold is considered. The stability of such a
configuration is analyzed. It is shown how closed-loop zeros can be
placed using such a scheme. As a consequence, it is proved that the gain
margin can be arbitrarily assigned by suitable choice of sampling time
and digital controller. The design procedure is constructive, using
state-space methods
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