RLC Filter Research Articles

Improvement of the Source Current Quality for a Shunt Active Power Filter Operating Using Hysteresis Technique with Stabilized Switching Frequency

Determining the current reference for a shunt active power filter (SAPF) can be carried out in many ways. Once the reference is determined, it can be shaped by SAPF switches with the use of pulse width modulation (PWM)/hysteresis control techniques. There are many variants of shaping the compensation waveform using these techniques. Nevertheless, regardless of the PWM/hysteresis technique adopted, a switching frequency current component appears in the system. It acts as a carrier used to inject a compensating current into the grid. Once the compensating current has been entered into the grid, the switching component should be reduced in it. This can be performed using RLC passive filters in various variants. The article discusses a variable/stabilized frequency hysteresis current control technique adapted for SAPF regulation with the use of current closed-loop control (source current direct control). For this technique, the passive filter should be placed outside the current control loop. The article focuses on examining the effectiveness of the interaction of the RLC filter with SAPF acting with such a control technique.

Different LC power filter topologies - effectiveness of reducing voltage distortion

This Paper aims to present a comparative study of different passive filter configurations. Five topologies of passive RLC filters for the purpose of the mitigation of harmonics voltage distortion are considered. Basis for evaluating the effectiveness of different filter topologies are simulation and laboratory studies.

Electromagnetic transient suppression for thyristor switch‐based auto‐passing neutral section system

AbstractThe auto‐passing neutral section (ANS), applied in the traction substation or section post (SP), is one of the effective methods to improve the continuity of power supply, and the electromagnetic transient is the key issue impacting its application value. An equivalent switching circuit is established to reveal the causes of the electromagnetic transient. The suppression methods for reducing transient overvoltage and inrush current are proposed, adopting an improved RLC filter to suppress the transient overvoltage with low active power loss, and a switching strategy to minimize magnetic flux variation. The correctness of the proposed methods has been confirmed by simulation and experimental results, which can improve the transient performance and increase the practicality of the ANS.

A robust optimal distributed control design for simultaneous voltage regulation and current sharing in DC microgrid

AbstractIn this article, a robust optimal distributed controller is designed for achieving average voltage regulation and current sharing in a DC microgrid. Each distributed generation unit (DGU) consists of a DC‐DC buck converter that supplies a local constant current load. The proposed controller only utilises output currents of converters and the possible maximum error values in estimation of series resistance in the RLC filter used in each DGU. The proposed controller is formed such that the possible estimation error is considered as an uncertain parameter. In addition to obtaining two main objectives, average voltage regulation, and current sharing, a robust control problem is solved through an optimal control technique to calculate controller parameters such that the stability of the grid is guaranteed. The stability of the closed loop system with parametric uncertainty is proved through Lyapunov analysis. The closed loop system with the suggested controller is tested by simulations and through different scenarios to reveal the reliable and satisfactory performance of the proposed robust optimal control structure.

Development of contactless switching devices for asynchronous machines in order to save energy and resources

To limit the inrush currents in the stator windings, various schemes for starting an asynchronous electric motor are used. In addition, the existing devices have a complex control system, which creates certain difficulties in installation and operation. But the analysis of scientific literature and materials from certain sources testifies to the insufficient study of this problem. In scientific work, the advantages and disadvantages of a new type of contactless starter are compared with contact and non-contact starters of various types. An original circuit of a new type of thyristor starter with a simplified design has been developed and manufactured, which has the ability to smoothly start and control the power consumption of asynchronous machines. Computer simulation of a new type of contactless starter with pulse-width modulation control in the Matlab Simulink program has been carried out: a pulse current is supplied to the controlled thyristor electrode on the basis of the pulse-width modulation control and the thyristor opens and passes the current, the resistance is set to decrease the input signal level. The design of the proposed starter is based on the combination of a thyristor starter with logical control, which has the ability to smoothly start and remote control of the power consumption of asynchronous electric motors, which has the ability to save energy and resources. Modern methods of implementing a logical control system, a pulse current generator with RLC filters, are proposed, and the task of remote monitoring and control of power consumption of asynchronouselectricmotors is set.

Optimisation-based modulation and control of matrix converters: A closed-form solution

A new optimisation-based modulation and control design for matrix converters is proposed. The design uses a quadratic optimisation programme to seamlessly combine control requirements on the input and output sides of the converter. On the input side, the requirements are to keep the source voltage and current in phase with each other and to attenuate transient oscillations caused by a resonant RLC filter, which is used to protect the voltage source from undesirable harmonics. On the output side the requirement is to track a desired current to feed a load. The novel aspects of the scheme are that (i) the optimisation is posed in terms of the converter’s modulation matrix, whose entries represent the duty cycles of each of the converter switches; and that (ii) the solution of the optimisation is obtained in closed form and shown to be implementable with a small number of elementary operations. Simulation results demonstrate the good performance of the proposed design.

Electronic Tunability and Cancellation of Serial Losses in Wire Coils.

This work presents a novel methodology to adjust the inductance of real coils (electronically) and to cancel out serial losses (up to tens or even hundreds of Ohms in practice) electronically. This is important in various fields of electromagnetic sensors (inductive sensors), energy harvesting, measurement and especially in the instrumentation of various devices. State-of-the-art methods do not solve the problem of cancellation of real serial resistance, which is the most important parasitic feature in low- and middle-frequency bands. In this case, the employment of serial negative resistance is not possible due to stability issues. To solve this issue, two solutions allowing the cancellation of serial resistance by the value of the passive element and an electronically adjustable parameter are introduced. The operational ranges are between 0.1 and 1 mH and 0.1 and 10 mH, valid in bandwidths from hundreds of Hz up to hundreds of kHz. The proposed concepts are experimentally tested in two applications: an electronically tunable oscillator of LC type and an electronically tunable band-pass RLC filter. The presented methodology offers significant improvements in the process of circuit design employing inductors and can be beneficially used for on-chip design, where serial resistance issues can be very significant.

An adaptive power point tracker in wind photovoltaic system using an optimized deep learning framework

ABSTRACT Over the past two decades, the integration and generation of photovoltaic power plants have risen to a huge level. The reason is increased pollution, which tends to cause ozone damage. The input source is a wind turbine, in which wind converts mechanical energy into electrical energy. The grid and solar array links have been optimized using the Maximum Power Point Tracker (MPPT), demonstrating the DC to DC converter. The deep learning framework could improve the performance and efficiency of MPPT. The RLC filter has been utilized for the specialized deduction in the current harmonic and voltage. The complexity, voltage fluctuation, and load imbalance were the causes to reduce power quality performance. Therefore, the proposed method has been designed to get error-free output. Furthermore, the MPPT based on a novel Vulture-based convolution neural model (VbCNM) is utilized to improve the efficiency and extract the power. The proposed method has resolved the open issues and technical implementation using the VBCNN technique. Furthermore, the precise error-free output has been determined by simulating MATLAB. The results obtained are more efficient, fast convergence, and clear. Finally, the simulation output was compared with various conventional methods and has attained a lower power loss as 0.1 kW and less sample times as 9 µs.

Magnetic Field Simulator Control System for Nanosatellites

Nano- and microsatellites are becoming more and more popular in the last ten years. The main reason for this is the low cost of their development and launch. Two such satellites of the CubeSat format have already been developed at the Igor Sikorsky Kyiv Polytechnic Institute. They have successfully completed their missions in orbit. Work on a new satellite is underway. Before flying into orbit, all satellites must pass a large number of ground tests. An important part of almost every satellite is its subsystem of orientation and stabilization. Since it contains magnetic sensors and electromagnets, special magnetic field simulators are used to test it. Such a simulator must create a uniform magnetic field with the required parameters. The most common design used to simulate a magnetic field is a Helmholtz cage. It was built in the nanosatellite laboratory of the Igor Sikorsky Kyiv Polytechnic Institute. This paper deals with the development of a control system for it. In the beginning, the design, parameters, and operation principle of the Helmholtz cage were described. It consists of six electromagnetic square shape coils with a side of 1.5 meters. Each coil has 52 turns of 1.29 mm wire. Such dimensions make it possible to obtain a spherical zone of uniformity of the magnetic field with a radius of 293 mm. The control system should regulate the current in the coils, change its direction and also control the parameters of the generated magnetic field. The existing solutions for such a system were analyzed. As a result, it was decided to use an H bridge circuit and pulse width regulation. The structural and schematic diagrams of the control system were developed. Were selected all necessary components, such as power module, central processing unit, microcontroller for PWM signal generation, and magnetometer for magnetic field control. To reduce the ripple of the output current, an RLC filter for the coil driver was developed. Its frequency response, current and voltage curves of its load were calculated analytically and coincided with practical results. An experimental layout of the control system was assembled. As a result of the tests, it was found that the system regulates the current in the coil from 0 to 6.8 A and can change its direction. The current ripple in the coils does not exceed 1 mA (peak-to-peak) at an average current of 0,574 A. The duration of the transient in the system is about 23 ms. These values meet the requirements and allow simulating any mode of satellite flight in orbit. The developed control system for the magnetic simulator allows testing the magnetic orientation systems of nanosatellites developed at Igor Sikorsky Kyiv Polytechnic Institute and will help in their preparation for the flight.

Indirect Space Vector Modeling of Asynchronous Motor for High-Speed Electric Vehicle Propulsion

This paper presents a high performance squirrel-cage asynchronous motor (ASM) drive, proposed for high-speed electric vehicle (EV) propulsion. This is an indirect space vector control (IDSVC) scheme in the rotor flux frame of reference, in which the modeling is based on synchronously rotating coordinate system transformation. Space vector pulse width modulation (SVPWM) inverter fetches the controlled stator direct and quadrature axis responses from the speed and current controllers and supply necessary voltages to stator of ASM. The output voltage waveforms of SVPWM inverter are not sinusoidal in nature, which allows undesired harmonics at high frequency of operation. This due to inconsistent switching frequency. A second-order low-pass (SOLP) RLC filter with Butterworth approximation and was designed and connected in series with SVPWM inverter to grab harmonic free speed and torque profile during high speed operations. Similarly, another SOLP with a quality factor equal to 2 is designed and speed profiles of both filters are compared. The system is developed and simulated in MATLAB/SIMULINK to observe the speed and torque tracking capabilities. Simulation results show that the performance of drive under steady and dynamic states were good with Butterworth filter approximation with robust IDSVC scheme adopted over wide range speed-drive curve.

Realization of an Electronically Tunable Resistor-Less Floating Inductance Simulator Using VCII

In this paper, a new implementation of an electronically tunable resistor-less floating inductance simulator using a second-generation voltage conveyor (VCII) is presented. The proposed circuit is resistor-free (benefiting from the intrinsic resistors at the Y terminals of the employed VCIIs) and composed of three VCIIs and a single grounded capacitor. Using a control current (Icon), the value of impedance at the Y terminal of the VCII is varied, whereby the value of the simulated inductance is tuned. The proposed circuit is designed at a transistor level using 0.18 µm TSMC CMOS parameters and ±0.9 V supply voltage. PSpice simulations are carried out to confirm the effectiveness of the proposed circuit. For a range of Icon from 0 µA to 50 µA, the value of the simulated L can be varied from −576 µH to −324 µH and from +316 µH to +576 µH for negative and positive simulators, respectively, in the frequency range of 100 kHz–3 MHz. Favorably, the value of the series resistance remains below 76 Ω. Simulation results show an error value below 4.8% and power consumption variation is from 1.64 mW to 1.92 mW. Moreover, application of the proposed circuit as a standard band-pass RLC filter is also included.

Dynamic Behaviors Analysis of a Novel Fractional-Order Chua’s Memristive Circuit

This paper proposed a novel fractional-order Chua’s memristive circuit. Firstly, a fractional-order mathematical model of a diode bridge generalized memristor with RLC filter cascade is established, and simulations verify that the fractional-order generalized memristor satisfies the basic characteristics of a memristor. Secondly, the capacitor and inductor in Chua’s chaotic circuit are extended to the fractional order, and the fractional-order generalized memristor is used instead of Chua’s diode to establish the fractional-order mathematical model of chaotic circuit based on RLC generalized memristor. By studying the stability analysis of the equilibrium point and the influence of the circuit parameters on the system dynamics, the dynamic characteristics of the proposed chaotic circuit are theoretically analyzed and numerically simulated. The results show that the proposed fractional-order memristive chaotic circuit has gone through three states: period, bifurcation, and chaos, and a narrow period window appears in the chaotic region. Finally, the equivalent circuit method is adopted in PSpice to realize the construction of the fractional-order capacitance and inductance, and the simulation of the fractional-order memristive chaotic circuit is completed. The results further verify the correctness of the theoretical analysis.

An improved passivity enforcement algorithm for transmission line models using passive filters

This paper proposes a simple but effective method based on shunt passive filters to enforce passivity on a frequency dependent transmission line model for multi-conductor cables and overhead lines. The passivity enforcement algorithm is applied to a widely-used frequency dependent line model in EMT-type software, the Universal Line Model. The passivity violating regions of the transmission line model are identified using the frequency sweep method. The passive shunt series RLC filters are added to the nodes of the transmission lines to eliminate passivity violations. Examples of multi-conductor underground cable systems are presented to demonstrate the validity of the proposed approach.

Superconducting Power Filter for Aircraft Electric DC Grids

A new device, referred to as Superconducting Power Filter (ScPF), is introduced to improve the stability of aircraft electric DC grids. This device is made of a non-inductive superconducting coil connected in series with a conventional RLC filter. The superconducting coil behaves as a nonlinear current-dependent resistance. By design, the superconductor does not undergo a full transition to the normal-resistive state and remains in the current-sharing regime. Thus, a quick response and recovery of the superconductor to transients can be achieved. In the present work, the thermo-electric model of the device incorporates a refined description of the transition from the superconducting state to the normal-resistive state of the superconductor. To check the feasibility of passive stabilization of embedded DC grids using ScPF, different widths and lengths of commercially available 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> generation High Temperature Superconducting (2G HTS) tapes were considered. We chose a case study simulating an equivalent circuit of a More Electric Aircraft (MEA) with an EPS-A3 architecture. For this particular case study, it is shown that the stability limit of the DC grid can be significantly increased, while preserving the reliability (no quench) and low cost (only a few meters of superconducting tape) of the ScPF.

Implement industrial super-dynamic voltage recovery equipment for power quality improvement in the industrial sector

This paper presents a control framework that utilization industrial super-dynamic voltage recovery equipment (ISDVR) to manage for significant power quality severe impacts such as voltage sags, consonant voltages, and harmonic voltage distortion in the industrial sector. The industrial sector is continuously facing various unsteady power quality problems because high affectability loads and high accuracy equipment demand high power quality power supply. When faults occur in this time, utilize industrial super-dynamic voltage recovery (ISDVR) to balance voltage on the load side of the industrial sector, so that is an effective method to improve power quality. The inverter and connected filter boost compensation for voltage harmonic distortion, voltage imbalance, and reduce different faults conditions. The different RLC filters can evacuate harmonic distortion. This paper clarifies the demand of industrial sector loads breaks down by poor power quality and implement ISDVR compensator for improving power quality with meet up the industrial load demand. The new Simulink model is assembled in MATLAB/Simulink to test performance. The restoration results proposed a new strategy that can ensure load side demand with a good quality power supply that is a fruitful technique for managing significant power quality.

Research on the Control Method of UPS Inverter Circuit Considering Additional Filtering Branch

Improving the electric power quality of the Uninterruptible Power Supply (UPS) is an important part of ensuring the reliability of the power system. In order to optimize the output voltage waveform of the UPS, a filtering branch can be added to the existing UPS inverter circuit. This paper studies the circuit control problem after adding the RLC filter branch in the UPS inverter circuit. Through the analysis of the inverter circuit directly considering the added filtering branch, the system state function of the circuit is constructed. A double closed-loop PI control strategy is designed to control the inverter circuit, and the effectiveness of the method is verified by simulation. Using the method in this paper, the output of the inverter circuit with the added filter branch can reach a stable state quickly. The research conclusions of this paper are helpful to improve the output power quality of UPS.

Reflected Wave Phenomenon in SiC Motor Drives: Consequences, Boundaries, and Mitigation

In voltage source inverter-based motor drives, the fast switching speeds of the power devices result in the reflected wave phenomenon. Besides the overvoltages at the motor end, there are overcurrents at the inverter end. The overvoltages increase stress on the motor and cable insulation, and the overcurrents affect the power devices. Wide bandgap (WBG) devices have lower switching losses and enable high switching frequencies. However, the reflected wave phenomenon is more pronounced in converters using WBG devices and could potentially increase the switching losses. This article presents a comprehensive analysis of the influence of the reflected wave phenomenon on the switching characteristics of SiC devices in motor drives. Notably, the effect of undamped reflected waves and different cable lengths on both the inverter end and motor end is studied. The analysis and experiments in this article uncover that, depending on the switching instance, the undamped reflected wave causes up to a 30% increase or up to a 15% decrease in the switching losses. A 12% reduction in the switching losses is observed with no cable to up to 20-m long cable. The last part of the article presents the design tradeoffs involved in designing a dv/dt filter. Five different dv/dt filters are compared in terms of their impact on the switching losses, dv/dt at the load, filter loss, and damping time of the reflected wave. The L filter and the RLC filter have around a 9% reduction in switching losses. The L filter suffers from increased damping time and higher reflected wave magnitude, making it unsuitable for high switching frequency applications. Overall, L // R filter offers the lowest filters losses with a 6% reduction in switching loss, making it more suitable for WBG devices-based high-speed motor drives.

A second‐generation voltage conveyor (VCII)–based simulated grounded inductor

SummaryIn this paper, an implementation of a simulated grounded inductor (SGI) based on a recently developed active building block called second‐generation voltage conveyor (VCII) is proposed. The proposed SGI employs two VCIIs, two resistors, and one grounded capacitor, which is preferred when integration is involved. More importantly, unlike most of the other previously reported SGIs, this one is free from any restrictive matching conditions. A complete analysis of nonidealities along with sensitivity treatment by considering parasitic impedances and nonideal gains of the VCII are performed. A simple VCII circuit is designed to be used in the implementation of the proposed SGI. To support the presented theory, Pspice simulation results using 0.18‐μm CMOS technology parameters and supply voltage of ±0.9 V are provided. On the basis of the achieved results, the proposed SGI operates in a good agreement with an ideal inductor. The power consumption is only 0.65 mW, and the parasitic series impedance is approximately 191.9 Ω. The applicability of the proposed SGI is tested by using it in a standard second‐order high‐pass RLC filter.

Power Quality Assessment of Grid-Connected PV System in Compliance with the Recent Integration Requirements

The generation and integration of photovoltaic power plants (PVPPs) into the utility grid have increased dramatically over the past two decades. In this sense, and to ensure a high quality of the PVPPs generated power as well as a contribution on the power system security and stability, some of the new power quality requirements imposed by different grid codes and standards in order to regulate the installation of PVPPs and ensure the grid stability. This study aims to investigate the recent integration requirements including voltage sag, voltage flicker, harmonics, voltage unbalance, and frequency variation. Additionally, compliance controls and methods to fulfill these requirements are developed. In line with this, a large-scale three-phase grid-connected PVPP is designed. A modified inverter controller without the use of any extra device is designed to mitigate the sage incidence and achieve the low-voltage ride-through requirement. It can efficiently operate at normal conditions and once sag or faults are detected, it can change the mode of operation and inject a reactive current based on the sag depth. A dynamic voltage regulator and its controller are also designed to control the voltage flicker, fluctuation, and unbalance at the point of common coupling between the PVPP and the grid. The voltage and current harmonics are reduced below the specified limits using proper design and a RLC filter. The obtained results show that the proposed controller fulfilled the recent standard requirements in mitigating power quality (PQ) events. Thus, this study can increase the effort towards the development of smooth PVPP integration by optimizing the design, operation and control strategies towards high PQ and green electricity.

Variation of THD in Output Quantities of Three Pahse SPWM-VSI by Varying the Parameters of RLC Filter Connected at Output of Inverter

Paper deals with the analysis of three phase Sinusoidal pulse width modulated (SPWM) Voltage source inverter output in term of total harmonic distortion (THD). Analysis is done by implementing the model in MATLAB/SIMULINK platform. By implementing filter at the output terminals of inverter, its current and voltage wave becomes purely sinusoidal. Analysis is carried out by varying RLC filter parameters and due to their variation, effect on THD in inverter filtered line voltage, line current &amp; phase voltage is measured. Filter inductance ‘L’ &amp; capacitance ‘C’ are varied one by one keeping other parameters constant &amp; effects has been plotted on various graphs &amp; listed in tables. It has been observed that by varying the RLC filter parameters THD in output quantities of SPWM VSI inverter shows a remarkable change in its value. This work may provide one of the best alternative solutions to design a filter for SPWM VSI inverter feeding to any drive.