LQR Control of Input LC filter of a Tram with On-board Energy Storage System

CZ.02.1.01/0.0/0.0/18_069/0009855, SGS-2021-021The main traction power converter of a trams is connected to DC trolley wire by input LC filter. The tram input LC filter is almost undamped resonant circuit, which is often loaded by the motor constant torque command. Sources of the input LC filter oscillation may be present on the vehicle, typically drive control influence. The source of LC filter excitation except the tram drive could be the tram’s trolley voltage caused by fluctuations in power consumption and harmonics from surrounding vehicles, and temporary loss of catenary voltage caused by crossings of insulated sections or icing on catenary. The next source could be the tram ESS, which is connected in parallel to the tram dc-link capacitor. The dynamic ESS control, which is necessary for majority of power management techniques, can also destabilize the LC filter. On the other hand, the proper ESS control could be used for LC- filter stabilization. The LQR based stabilization of LC filter using ESS is presented in this paper

Artificial Intelligence and COVID-19: Deep Learning Approaches for Diagnosis and Treatment

COVID-19 outbreak has put the whole world in an unprecedented difficult situation bringing life around the world to a frightening halt and claiming thousands of lives. Due to COVID-19’s spread in 212 countries and territories and increasing numbers of infected cases and death tolls mounting to 5,212,172 and 334,915 (as of May 22 2020), it remains a real threat to the public health system. This paper renders a response to combat the virus through Artificial Intelligence (AI). Some Deep Learning (DL) methods have been illustrated to reach this goal, including Generative Adversarial Networks (GANs), Extreme Learning Machine (ELM), and Long/Short Term Memory (LSTM). It delineates an integrated bioinformatics approach in which different aspects of information from a continuum of structured and unstructured data sources are put together to form the user-friendly platforms for physicians and researchers. The main advantage of these AI-based platforms is to accelerate the process of diagnosis and treatment of the COVID-19 disease. The most recent related publications and medical reports were investigated with the purpose of choosing inputs and targets of the network that could facilitate reaching a reliable Artificial Neural Network-based tool for challenges associated with COVID-19. Furthermore, there are some specific inputs for each platform, including various forms of the data, such as clinical data and medical imaging which can improve the performance of the introduced approaches toward the best responses in practical applications

Adaptivní řízení spínaného reluktančního motoru bez čidla polohy

This paper describes position estimator of switched reluctance motor drive based on artificial neural network model. After the introductory stage, main algorithms used for position and resistance of rotor winding estimation are explained. Estimation algorithms are designed in Matlab software and implemented into FPGA

Estimation of selected quantities in the field of electric drives and active power filters

Tato disertační práce se zabývá estimací vybraných veličin elektrických pohonů a aktivních filtrů. První část práce popisuje estimaci polohy a rychlosti rotoru dvou typů elektrických pohonů. Prvním je pohon se spínaným reluktančním motorem. Tento typ motoru je elektronicky komutovaný a znalost polohy rotoru je nutným předpokladem pro kvalitní provoz pohonu. Druhý typ pohonu je vektorově řízený synchronní motor s vnějšími permanentními magnety. Zde je nutná znalost polohy rotoru tj. i permanencích magnetů pro potřeby vektorového řízení orientovaného na rotorový tok. Práce se dále věnuje prediktivní estimací nestability vstupního LC filtru trakčního vozidla napájeného ze stejnosměrné troleje a jeho aktivní stabilizací. Prediktivní algoritmus odhaduje možné budoucí kmity vstupního LC filtru a zásahy do řízení pohonu se synchronním motorem s vnějšími permanentními magnety (řízeného pomocí přímého řízení momentu) se snaží tyto kmity potlačit (a při přechodových dějích pohonu je nevybudit). Poslední část disertační práce se zabývá estimací první harmonické proudu odebíraného nelineární zátěží ze sítě s lehkými frekvenčními fluktuacemi mezi 49 až 51 Hz. Odhadnutá první (fundamentální) harmonická proudu je dále použita pro řízení jednofázového paralelního aktivního filtru k potlačení vyšších harmonických odebíraných ze sítě jednofázovou nelineární zátěží.Katedra elektromechaniky a výkonové elektronikyObhájenoThe dissertation thesis deals with estimation of selected quantities in the field of electric drives and active power filters. The first part of this work is concerned to estimation of velocity and rotor position of two types of electric drives. First drive employs a switched reluctance motor. This type of motor is an electronically switched (commutated) and the information about rotor position is necessary for a proper operation. Second type of the drive employs a permanent magnet synchronous motor with vector control. The information about the position of the rotor with permanent magnets is needed for rotor flux-oriented vector control algorithm. Next, the thesis deals with predictive instability estimation and active stabilization of an input LC filter of a traction vehicle which is supplied by DC-trolley wire. The predictive algorithm estimates future possible oscillations of the input LC filter and it tries to eliminate these oscillations by interventions to the control algorithm of the drive with permanent magnet synchronous machine (direct torque control). Last part of the thesis investigates first harmonic component estimation in a distorted current drawn by nonlinear load, which would operate also by frequency fluctuations from 49 to 51 Hz. The estimated fundamental current is then used for control of a single-phase shunt-type active power filter which eliminates unwanted components drawn by nonlinear load

Real-time Algorithm for the Transformation of Multiple Harmonic Unbalanced Voltages into Symmetrical Components

The Fortescue theorem is a well-known transformation technique for parameter identification in three-phase systems. It is a valuable tool that transforms an unbalanced system into symmetrical components. This method itself can not be used in a real-time system because it needs to identify individual vectors of the voltage. The solution proposed in this paper is to combine the Fortescue theorem with a second-order generalized integrator (SOGI). The SOGI algorithm provides two functions. Firstly, it identifies voltage vectors. Secondly, it works as a band-pass filter. This means it can deal with the systems containing multiple harmonics, processing them individually. This paper evaluates the performance of the proposed algorithm, with a focus on harmonic selectivity and speed of the reaction during transients

Study of 3.3 MW voltage-source active rectifier

This paper deals with the behavior and stability of three-phase voltage-source active rectifier with rated power 3.3 MW. This high-power converter is connected to power grid via transformer and input clean power filter. The main purpose of the article is check the stability of the input filter and describes harmonics spectrum at the output DC-link. For these reason, the power converter tested by accurate simulation study including the consideration of time delay of control, dead times and losing in semiconductor components

Real-time Algorithm for the Transformation of Multiple Harmonic Unbalanced Voltages into Symmetrical Components

The Fortescue theorem is a well-known transformation technique for parameter identification in three-phase systems. It is a valuable tool that transforms an unbalanced system into symmetrical components. This method itself can not be used in a real-time system because it needs to identify individual vectors of the voltage. The solution proposed in this paper is to combine the Fortescue theorem with a second-order generalized integrator (SOGI). The SOGI algorithm provides two functions. Firstly, it identifies voltage vectors. Secondly, it works as a band-pass filter. This means it can deal with the systems containing multiple harmonics, processing them individually. This paper evaluates the performance of the proposed algorithm, with a focus on harmonic selectivity and speed of the reaction during transients

Single-phase synchronization for traction active rectifier

This paper introduces the advanced synchronization method second order general integrator phase locked loop modified especially for voltage synchronization exclusively for traction active rectifier. Designed synchronization is characterized by resistance to interfaces and especially quick response to frequency fluctuations. The behavior of designed synchronization method was analyzed by simulations tests and the final synchronization adjustment was suggested

Electromagnetic interference of single-phase AC-DC traction converter

The main goal of this paper is to analyze a low harmonic interferences of ac-dc traction converter and the influence of selected signals. In this case, the ac-dc converter is based on H-bridge topology. This type of converter is important part of a majority modern ac locomotives. The main interest was focused on 25 kV / 50 Hz traction system used in Czech Republic. The simulation and experimental results of single-phase voltage-source active rectifier with harmonic analyses of input ac currents and voltages are presented in this paper. This study is performed on the real ac-dc converter including long dead time delays, discrete control delay, semiconductors threshold voltage and conductive losses

Peak to Peak Current Minimization by Differential Evolution Optimization

This paper deals with differential evolution optimization of peak to peak current value, which consist of several harmonics with defined amplitudes. The actual amplitude of the current signal is computed as a sum of harmonics with different frequencies and depends on the harmonics amplitudes, phases and actual time. The paper presents the optimization algorithm of harmonic's phases to reach the highest amplitude of all harmonics with the lowest absolute amplitude of resulted current (computed as a sum of all harmonics). The optimized current waveform is used as a reference signal for analogue hysteresis controller of single phase Hbridge inverter. The inverter works as a current source connected in parallel to auxiliary winding of Petersen coil. The H-bridge converter is used for injecting of selected current harmonics into power network grid. The measured converter voltage responses of injected current harmonics are used for grid resonant frequency identification. This information is used for tuning of Petersen coil