This paper presents four single-phase universal active power filters (UAPF) topologies with 4, 5, 6 and 7 legs. The proposed systems are based on AC/AC converters with two transformers. They are suitable to improve the harmonic distortion in the grid currents and a voltage compensation. The filter uses a combination of two series filters and one shunt filter sharing a single DC-link. The proposed active filters are capable of generating input and output voltages with low harmonic content and consists of low-power switches. The complete control system, including the PWM techniques based on vector approaches, is developed. Simulation and experimental results are shown for validation purposes.

Single-phase universal active power filter based on AC/AC converters

In urban rail transit, there is a large number of harmonics brought by diode rectifiers, and shunt active power filters (APFs) are an effective method of harmonics rejection. Traditional shunt APFs work with a dedicated DC link leading to complexity, while those with a common DC bus but using non-isolated topologies bring serious problems of zero-sequence circulating current (ZSCC), which introduce losses and provoke poor quality. Consequently, this paper first analyzes the limitations of traditional non-isolated APFs on modulation radio. Based on the analysis, this paper put forward a novel isolated APF with a common DC link based on existing diode rectifiers in urban rail transit, which realizes braking energy recovery as an additional function. To this end, harmonics brought by diode rectifiers are reduced while rejecting ZSCC. Meanwhile, braking energy can feedback to the city grid with lower harmonics. Finally, simulation and experiment using a 1-kW prototype converter verify the feasibility and validity of the proposed converter on harmonics suppression and braking energy recovery.

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Shunt Isolated Active Power Filter With Common DC Link Integrating Braking Energy Recovery in Urban Rail Transit

This article presents a model predictive current control of a shunt active power filter based on 7-level cascaded H-bridge converters. By using the spacial vector modulation approach into the model predictive control, a considerable reduction of the computational burden is achieved and makes possible the real-time implementation in a custom experimental setup. Then, the current harmonics on the grid side, caused by non-linear loads connected to the point of common coupling, are compensated. The experimental results confirmed the feasibility and efficacy of the proposed controller.

https://www.frontiersin.org/articles/10.3389/fenrg.2022.779108/pdf

MPC with Space Vector Phase-Shift PWM (SV-PSPWM) Technique with Harmonic Mitigation Strategy for Shunt Active Power Filters Based on H-Bridge Multilevel Converter

In this paper, a new way to mitigate the current interactions is proposed. The problem of current interactions arises when a modular three-phase (3-phase) rectifier (three single-phase modules) with boost converter for power factor correction (PFC) is used. A new differential-mode choke filter is implemented in the developed boost converter. The choke here is a specially made differential inductor in the input of the boost converter that eliminates the known current interactions. To prove the new concept, a study of the level of mitigation of the current interactions is presented. The control is operated in continuous driving mode (CCM), and the popular UC3854B circuit was used for this. The rectifier proposal is validated through a set of simulations performed on the PSIM 12.0 platform, as well as the construction of a prototype. With the results obtained, it is confirmed that the differential-mode choke filter eliminates the current interactions. It is observed that at the input of the rectifier, a sinusoidal alternating current with a low level of harmonic distortion is consumed from the grid. The sinusoidal shape of the phase current proves that a better power factor capable of meeting the international standards is obtained, and that the circuit in its initial version is operational. This proven result promises a good PFC operation, to guarantee the better quality of the electrical energy, being able to be applied in systems that require a high PFC, e.g., in battery charging, wind systems, or in aeronautics and spacecrafts.

Current Interactions Mitigation in 3-Phase PFC Modular Rectifier through Differential-Mode Choke Filter Boost Converter

This paper proposed two universal active power filter (UAPF) topologies for reactive power and harmonic compensation. The proposed system is a combination of series and shunt active power filters. They are suitable to improve the harmonic distortion in the grid currents and a voltage compensation. The filters are composed of three three-phase converters resulting in nine legs. The first (configuration I) can operate with floating dc-link capacitor or an auxiliary DC source on the series filter and the second one (configuration II) uses a combination of two series filters and one shunt filter sharing a single dc-link. The complete control system, including the PWM techniques, is developed and a comparison between the configurations is done. Simulation and experimental results are shown for validation purposes.

Universal active power filters based on nine-leg converter

The growing number of consumers representing non-linear loads has led to an increase in the level of harmonics and poor power quality. It is not news to apply active power filtering (APF), but the drawback is the lower efficiency and complexity. The described here active power filter control system is simpler and more efficient. It is based on a relay current regulator and its converter uses the existing DC bus of the rectifier. The theoretical basis of the APF is described. A model of the proposed APF (with its suggested control system and the common DC link) is simulated in Matlab. The result of this simulation demonstrates that the level of the Total Harmonic Distortion (THD) of the input current is less than 3 %. The input current matches the phase of the input (mains) voltage: i.e. the consumption of reactive power from the grid is minimized. The simulation is confirmed by experimental study of the APF with Common DC Link. The corresponding results are provided.

Active power filter with common DC link for compensation of harmonic distortion in power grids

This paper discusses a smart laboratory robotics system designed to allow students remote connection and work with robotic manipulation devices and applications, as well as for teaching and conducting collaborative research projects in the field of electrical engineering and automation. A scheme of connecting all the necessary robotic devices and video cameras to the main server in the laboratory for the possibility of connecting to a remote desktop is presented. The developed solution for remotely connecting students to a physical robotic cell, which is connected to the lab server, is presented. Thanks to the proposed system, it was possible to conduct a debugging of new solutions for the control of robotic manipulation systems on a particular connected technological equipment. A telepresence system with real-time video streaming of physical robotic cell was developed to monitor the behavior of the robotic system remotely in order to understand the process of the connected devices clearly after the solution was uploaded to the robot controller.

Smart Educational Robotics Laboratory Ecosystem for Remote Control of Robotic Manipulators Through Telepresence Technologies

It is necessary to stabilize the dynamic torque of the motor at the start of mechanisms with cyclical action, such as machine tools, which perform the machining of large cylindrical parts and require their rotation. The research carried out has shown that such requirements are met by the proposed system of frequency cascade electric drive, based on an induction motor with a phase-wound rotor and equipped with additional elements enabling the transfer of sliding energy from the motor-rotor circuit to the DC link of the frequency converter. A pulsed control system of the inverter input current and correction of the control signals as a function of the motor torque value determined by means of a torque observer is proposed.

Frequency-Cascade Electric Drive System for Induction Motor Starting Torque Stabilization

An integral part of modern medicine is its technical equipment. The constantly evolving methods of prevention and treatment require ever more stringent and precise characteristics from the equipment that implements these methods. To ensure such characteristics, technical equipment must be constantly updated and improved in line with current technology and trends. Collector-driven DC motors have significant disadvantages, including the need for timely maintenance of the collector-brush unit and limited service life due to collector wear. In recent years, permanent magnet synchronous motors have become more and more common and their design is continually being improved for different applications and their control systems are being improved. The characteristics of these servomotors can easily replace the DC collector motors. In this article, we will give an example of the modernization of a robotic complex for the recovery of walking skills by replacing the installed servomotors.

Electric Drive Modernization by Replacing Brushed DC Motor with Permanent Magnet Synchronous Motor in Rehabilitation Robotic System

The article considers a vector control system for asynchronous electric drive of belt conveyors, which uses an adaptive observer to control the speed of the electric drive. This allows you to increase the reliability and inter-interval maintenance of the electric drive. The requirements for the observer are determined, its mathematical description is made, and the law of adaptation is determined. In the Matlab Simulink package, a computer simulation of the proposed sensor-free control system is performed. A study of the robustness of the actuator in terms of the drift of the parameters of the motor when powered from the inverter, expressed by the integral criterion for parametric robustness. Based on the results obtained, a comparison is made and conclusions are drawn about the advantages and disadvantages of using an adaptive observer in comparison with other types of observers.

Vladimir Pikalov

Papers

Active power filter with common DC link for compensation of harmonic distortion in power grids

Smart Educational Robotics Laboratory Ecosystem for Remote Control of Robotic Manipulators Through Telepresence Technologies

Frequency-Cascade Electric Drive System for Induction Motor Starting Torque Stabilization

Electric Drive Modernization by Replacing Brushed DC Motor with Permanent Magnet Synchronous Motor in Rehabilitation Robotic System

Modeling the system of a dovetailless asynchronous electric drive for conveyor mechanisms