Lidé

Ing. Pavel Karlovský, Ph.D.

Všechny publikace

Current Ripple Reduction of Predictive Torque-Controlled Induction Motor Drive Using Delta-Star Switchover

  • DOI: 10.3390/app11062863
  • Odkaz: https://doi.org/10.3390/app11062863
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The current and torque ripple of inverter-fed induction motor drives is an inherent problem of control strategies working with switching frequencies in the range of multiple kilohertz, such as direct torque and, more recently, predictive torque control. If the drive operates in a wide-speed and wide-torque range and is equipped with a machine with an accessible terminal block whose winding is nominally connected in delta, then the current and torque ripple can be reduced by utilizing the delta-star winding changeover technique. When the winding configuration is switched from delta to star, the instantaneous motor phase voltage peak is lowered, and its total harmonic distortion is reduced. However, the control strategy must be adjusted according to the actual winding topology, mainly due to the difference in the coordinate transformations of the measured currents and the difference between the phase voltage vectors obtained from the inverter. This paper proposes a predictive torque control of an induction motor drive with a switchable delta-star winding configuration. The paper is supported by theoretical background, and the key idea is verified by simulations in MATLAB/Simulink and experiments conducted on a dSPACE-controlled 5.5-kW laboratory drive. The simulations validated the presented equations and show the effects of not respecting the actual winding topology. The experiments mainly focused on analyzing the total harmonic distortion of the currents and consumed electrical power in multiple operating points.

Estimation of Stator Voltage of Inverter-Supplied Induction Motor Using Kalman Filter

  • DOI: 10.1007/978-3-030-53021-1_7
  • Odkaz: https://doi.org/10.1007/978-3-030-53021-1_7
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Most of the control algorithms of variable speed drives with induction motor require the knowledge of the stator voltage vector applied to the motor ter-minals. This vector is usually reconstructed from the known microcontroller’s PWM signals or the commanded voltage for the inverter is used within the con-trol algorithm. However, these solutions require a DC-link voltage sensor and compensation of the nonlinear inverter behavior. In this paper, stator voltage es-timator based on the Extended Kalman filter is proposed. This approach requires neither the knowledge of the DC-link voltage nor the nonlinear model of the in-verter. Only the knowledge of the stator currents and the rotational speed is need-ed. The proposed estimator is verified within the simulation of predictive-torque control of induction motor drive in Matlab Simulink where the comparison of the applied and the estimated voltage vector is presented along with their harmonic analysis. The accuracy of the estimated voltage vector shows its suitability for further inverter nonlinearities investigation.

Capability of Predictive Torque Control Method to Control DC-link Voltage Level in Small Autonomous Power System with Induction Generator

  • DOI: 10.1007/978-3-030-14907-9_74
  • Odkaz: https://doi.org/10.1007/978-3-030-14907-9_74
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    In a small autonomous power system, the electric power is usually produced by means of an electric machine operated as a generator. The often used one is an in-duction generator. The generator supplies the DC-link through the controlled converter (voltage source inverter – VSI). The appliances connected to the same DC-link consume power and therefore the DC-link capacitor is discharged. To maintain the decreasing DC-link voltage level, the same power amount must be delivered by the generator. In case of the induction generator, its control is specif-ic as no external source for machine excitation is present. To obtain the torque value desired by the DC link voltage PID controller, the generator is usually con-trolled by the field-oriented control (FOC) method or direct torque control (DTC) method. However, the model predictive control (MPC) method has been utilized for electric machine control in recent time. The paper explores the possibility of employing the predictive torque control (PTC), which is often used implementa-tion of MPC in this type of applications. The PTC method ability to control the DC-link voltage in a small autonomous power system has been verified experi-mentally on a laboratory system with induction generator.

Iron Loss Minimization Strategy for Predictive Torque Control of Induction Motor

  • DOI: 10.3390/electronics9040566
  • Odkaz: https://doi.org/10.3390/electronics9040566
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Today’s modern control strategies of an induction motor (IM) drive require a power source with an adjustable output voltage frequency and amplitude. The most commonly used converter topology is a two-level voltage-source inverter (VSI). However, the utilization of a VSI introduces additional voltage and current distortion, which leads to additional power losses in the machine’s magnetic circuit. Both the transistor switching frequency and the type of the inverter control determine the total harmonic distortion (THD) of the motor’s phase currents. In this paper, the influence of the inverter DC-link voltage on the iron losses of an IM controlled by a predictive torque control (PTC) is presented. It is shown that if the IM drive operates below the rated speed, it is possible to modify the PTC algorithm to reduce the additional iron losses caused by the non-harmonic inverter output voltage. The control of the DC-link voltage is achieved by using a silicon-controlled rectifier. Experiments were conducted on a 5.5 kW IM controlled by PTC, and the results are compared against a sinusoidal voltage supply created by a synchronous generator.

Optimum Flux Search Control on Induction Motor Drive with Predictive Torque Control

  • DOI: 10.1109/EPE51172.2020.9269212
  • Odkaz: https://doi.org/10.1109/EPE51172.2020.9269212
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    This work deals with a real-time optimum flux search control (SC). The method is integrated into Predictive Torque Control (PTC) of induction motor drive (IMD). The proposed predictive search control searches the optimum stator flux amplitude, at which the current amplitude is the lowest. The output of the SC is used as a reference for the PTC controller. As the control variable of the proposed SC, the predicted stator current vector amplitude is utilized. The method was verified experimentally on a laboratory drive with a 5.5 kW induction motor. The IMD achieves a current minimization while maintains the working point defined by the speed and load. The experiment shows good results during steady-state and sufficient performance during transients.

Predictive Torque Control of Induction Motor with Integrated DC-Link Voltage Optimisation

  • DOI: 10.1049/iet-pel.2019.1597
  • Odkaz: https://doi.org/10.1049/iet-pel.2019.1597
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    This paper proposes a new method leading to a reduction in the current and torque ripple of an Induction Motor (IM) drive controlled by a Predictive Torque Control (PTC). The method lies within the optimisation of DC-link voltage magnitude by a three-phase thyristor bridge rectifier. Using a controlled rectifier, the DC-link voltage can be adjusted in such way that the ripple of the IM state variables, caused mainly by treating the inverter as a source of only eight voltage vectors, is significantly reduced. Another positive consequence of the proposed algorithm is the reduction of DC-link-dependent switching losses. The DC-link optimisation algorithm is integrated within the PTC that is used for the torque and flux control. The theoretical analysis of the DC-link voltage influence on the drive behaviour is supported by simulation and experimental results conducted on a 5.5 kW IM drive, which confirms the benefits of the PTC with the DC-link voltage optimisation.

Induction Motor Drive Direct Torque Control and Predictive Torque Control Comparison Based on Switching Pattern Analysis

  • DOI: 10.3390/en11071793
  • Odkaz: https://doi.org/10.3390/en11071793
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    This paper describes a switching pattern generated in case of induction motor drive predictive torque control (PTC) compared to a switching pattern of direct torque control (DTC). PTC is a modern control method for electric drives based on model predictive control (MPC). DTC is a very powerful method and is today an industrial standard for controlling an induction motor drive. Its usage is wide-spread, mainly in high-power applications. However, the method suffers from a few disadvantages. One of the causes of the control method’s problematic behavior is choosing the switching combinations in the flux sector. Another inconvenience is the common selection table not including all voltage vectors in given sector. By these factors, the ripples of flux vector trajectory and torque waveforms are influenced. The longer the sample time is, the more significant the influence of factors becomes, because only a few steps occur within one turn of the magnetic flux vector. Based on the detailed analysis, the reasons of the different performance of both systems are explained. The analysis performed by simulation in Matlab Simulink environment has proved that, while DTC might choose voltage vector that pushes system away from the reference values, the MPC always chooses the most proper vector. The experimental results measured on the real drive confirm the appropriate vector selection, just in case of the predictive control method.

Loss Reduction in Induction Motor Drive Using Model Predictive Control

  • DOI: 10.1109/ECAI.2018.8679073
  • Odkaz: https://doi.org/10.1109/ECAI.2018.8679073
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The induction motor drive with variable speed is a very common drive in many applications. To ensure the induction motor drive speed control, the sophisticated control methods must be utilized. In the paper, the Model Predictive Control (MPC) is employed. This method is usually used in order to control the induction motor flux amplitude and torque values. The induction motor is powered by the semiconductor voltage source inverter. Switching the semiconductor devices and current flow cause arise of losses in inverter. To decrease the losses, the modified MPC method is derived in the paper. In the Matlab Simulink environment reached simulation results show a reduction in losses at the newly modified control strategy compared to the conventional MPC method.

Wheel Slip Determination Capability of Locomotive Driven by Model Predictive Control

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Most of the railway traction vehicles are moved thanks to the transfer of traction, braking force by small contact area between wheels and rail (steal to steal contact). The ability of force transfer by contact area or also the sum of the contact area physical properties is called adhesion. In order to utilize maximum transferable force, a slip controller has to be added into drive control structure. The paper studies possibility of the Model Predictive Control (MPC) strategy application to support the slip controller function. The considered slip controller is based on the speed and current response of the torque reference signal injection. Therefore, the controller requires high torque control accuracy. Results of MPC are compared with the Direct Torque Control (DTC) strategy that is often used for control of high power drives with induction motor (IM).

Application of MRAS algorithm to replace the speed sensor in induction motor drive system

  • DOI: 10.1016/j.proeng.2017.06.073
  • Odkaz: https://doi.org/10.1016/j.proeng.2017.06.073
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. In order to obtain the speed information an optical sensor is usually utilized. However, it is not always advantageous because of the whole drive robustness decrease caused by the speed sensor inclusion. The paper presents some simulation and measurement results in case of the MRAS (Model Reference Adaptive System) method employing in attempt to eliminate the induction motor drive speed sensor. The operation principle is explained and a mathematical model of the drive system is created. The MRAS method influence on the drive behaviour is examined in simulation environment and experimentally. Finally, the experimental results and comparison of the drive behaviour with and without the speed sensor are discussed.

Application of MRAS algorithm to replace the speed sensor ininduction motor drive system

  • DOI: 10.1016/j.proeng.2017.06.073
  • Odkaz: https://doi.org/10.1016/j.proeng.2017.06.073
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. In order to obtain the speed information an optical sensor is usually utilized. However, it is not always advantageous because of the whole drive robustness decrease caused by the speed sensor inclusion. The paper presents some simulation and measurement results in case of the MRAS (Model Reference Adaptive System) method employing in attempt to eliminate the induction motor drive speed sensor. The operation principle is explained and a mathematical model of the drive system is created. The MRAS method influence on the drive behaviour is examined in simulation environment and experimentally. Finally, the experimental results and comparison of the drive behaviour with and without the speed sensor are discussed.

Comparison of sensorless AC drive operation using MRAS method or Luenberger observer

  • Autoři: Ing. Pavel Karlovský, Ph.D., prof. Ing. Jiří Lettl, CSc.,
  • Publikace: Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP), 2017 International Conference on. IEEE, 2017. p. 281-286. ISBN 978-1-5090-4489-4.
  • Rok: 2017
  • DOI: 10.1109/OPTIM.2017.7974984
  • Odkaz: https://doi.org/10.1109/OPTIM.2017.7974984
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Induction motor is utilized in wide area of electric drive applications. If sophisticated control of speed or torque is required, the actual rotor angular velocity must be known at every time instant. To obtain the speed information, an optical sensor is usually utilized. However, the usage of such sensor brings some undesired effects. The paper compares two very often used methods on a specific induction motor drive. The MRAS (Model Reference Adaptive System) method and Luenberger observer are tested on the drive controlled through the DTC (Direct Torque Control) strategy. Operation principles of both methods are explained and a mathematical model of the drive system is created. These methods promise very precise speed estimation in simulation environments but in real operation they work less accurate. This paper brings the results measured on real drive and shows the limitations of the methods that do not occur in simulations.

Improvement of DTC Performance Using Luenberger Observer for Flux Estimation

  • DOI: 10.1109/EPE.2017.7967286
  • Odkaz: https://doi.org/10.1109/EPE.2017.7967286
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.

Influence of speed and flux estimation by Luenberger observer on IM drive with DTC

  • DOI: 10.23919/AE.2017.8053585
  • Odkaz: https://doi.org/10.23919/AE.2017.8053585
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The direct torque control (DTC) strategy is one of the most performance methods for induction machine (IM) drive torque control. The controlled stator magnetic flux and torque cannot be easily measured and therefore must be calculated using an IM mathematical model. This paper examines the impact of the replacement the original voltage IM model by Luenberger observer on the drive performance. As the original model requires only voltage and current, the observer is implemented in such a way that the same input variables can be used. The models are created and tests are carried out experimentally employing the dSPACE platform on induction motor of power 5.5 kW. The experimental results indicate better performance of the control strategy based on Luenberger observer.

Influence of Switching Frequency on Torque Ripples in Model Predictive Control of Induction Motor Drive

  • DOI: 10.1109/ECAI.2017.8166398
  • Odkaz: https://doi.org/10.1109/ECAI.2017.8166398
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The proper control of induction motor drive is an important task in many applications. Usually, the motor is supplied from voltage source inverter and the required voltage is calculated according to the actual and past states of the motor. Unlike this, the predictive methods calculate also the future state and adjust the voltage accordingly. The model predictive control method calculates the effects of all possible future states in the next step and chooses the best action according to desired criteria. In the paper, this method is employed in the induction motor drive and the influence of the switching frequency on the torque and flux waveform ripples are examined in simulation environment Matlab Simulink.

Predictive Control of Induction Motor Drive Using dSPACE Platform

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Recently, the induction motor drives have become very popular in the area of controlled drives. Nowadays, a great effort is put on increasing their efficiency. The most widely used control method is the direct torque control (DTC). However, this method suffers from the torque ripple and current waveform distortion. The modification using predictive algorithms is becoming a popular approach. This paper presents a predictive control on the dSPACE DS1103 system and compares the method with DTC.

Improvement of induction motor drive performance using predictive control method instead of DTC method

  • DOI: 10.1109/AE.2016.7577255
  • Odkaz: https://doi.org/10.1109/AE.2016.7577255
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Considering the disadvantages of induction motor drive such as torque ripple and current waveform distortion when using direct torque control (DTC) method, the method substitution might improve the drive behaviour. The authors suggest instead of the DTC method using the predictive method based on similar principles. In the paper, both methods are examined. Then on the induction motor drive yet controlled by DTC algorithm, the predictive method is implemented and performances of both control strategies are compared.

Sensorless Determination of Induction Motor Drive Speed Using MRAS Method

  • DOI: 10.1109/ECAI.2016.7861079
  • Odkaz: https://doi.org/10.1109/ECAI.2016.7861079
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    In most cases, using of an optical sensor represents the most common solution to obtain the induction motor actual speed. As in some cases the use of the speed sensor carries number of problems, an effort to find a solution that does not require a speed sensor is obvious in recent time. The paper presents some results of employing MRAS (Model Reference Adaptive System) method for sensorless induction motor shaft speed determination. The working principles and the possible algorithm mathematical derivation are described. Results of the drive performance simulation in MatLab/Simulink environment are presented. Finally, the algorithm is verified on the real induction motor drive utilizing dSPACE platform. Obtained results demonstrate good function and performance of the system.

Induction Motor Drive Predictive Control Method Analysis and Comparison with Fundamental Direct Torque Control Method

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The authors propose new modification of the direct torque control method based on voltage vector prediction. The principle of the method is explained and the mathematical description of the system is provided. The control algorithm is implemented in simulation environment MatLab / Simulink and its behaviour is tested on the mathematical model of an induction motor drive. Then, the control algorithm is verified on the real drive with induction motor with dSPACE control system. The results from the simulations and measurements are presented and compared with those when using the fundamental direct torque control method.

Induction Motor Drive Predictive Direct Torque Control Method

  • DOI: 10.1109/RADIOELEK.2015.7129045
  • Odkaz: https://doi.org/10.1109/RADIOELEK.2015.7129045
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The paper deals with development of the induction motor drive direct torque control (DTC) based on the next step voltage vector prediction. The principle of the method is explained and the system mathematical description is provided. The derived control algorithm is implemented both in the simulation software MatLab/Simulink and on the real induction motor drive with dSPACE control system. Simulated and measured results in steady states and transients are presented.

Predictive Control of Induction Motor Drive Using dSPACE

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Since the induction motor drives have gained its popularity among regulated drives area, the great effort is put on increasing their efficiency. The use of predictive algorithm to control their speed is becoming a popular approach that preserves high efficiency. This paper presents implementing predictive control on the dSPACE DS1103 system, where the dSPACE is the control part of the system, drives the outputs of the power IGBTs and provides online communication with computer through ControlDesk.

Rozbor prediktivní metody přímého řízení momentu pohonu s asynchroním motorem v prostředí Matlab Simulink

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    Příspěvek se zabývá prediktivní metodou přímého řízení momentu pohonu s asynchronním motorem. Je proveden teoretický rozbor metody, vytvořen matematický popis systému a ověřena funkčnost navrženého algoritmu v prostředí Matlab Simulink na modelu pohonu s asynchronním pohonem. Získané výsledky prokazují dobré chování pohonu v ustálených i přechodných stavech.

Simulation and Development of Induction Machine Predictive Direct Torque Control Method

  • Autoři: Ing. Pavel Karlovský, Ph.D.,
  • Publikace: Poster 2015. Praha: České vysoké učení technické v Praze, 2015. ISBN 978-80-01-05728-5.
  • Rok: 2015
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The paper deals with development of the induction motor drive direct torque control (DTC) based on the next step voltage vector prediction. The prediction calculations come out from the flux vectors relations in induction motor, estimation of actual drive values and reference values for stator magnetic flux amplitude and torque. The principle of the method is explained and the mathematical description of the system is provided. The whole control algorithm with induction motor and load is implemented in the simulation environment MatLab/Simulink and the simulated results in steady states as well as in transients are presented.

Simulation and Development of Induction Machine Direct Torque Control

  • Autoři: Ing. Pavel Karlovský, Ph.D.,
  • Publikace: POSTER 2014 - 18th International Student Conference on Electrical Engineering. Prague: Czech Technical University, 2014. ISBN 978-80-01-05499-4.
  • Rok: 2014
  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    This paper deals with the development of the induction machine direct torque control (DTC), it explains basic principles of this method and it describes the simulation model of an induction machine and of the DTC method. Further, the workplace which has been realized at the Department of Electric Drives and Traction is introduced. At the end, the simulation and experimental results are presented.

Analysis of the Influence of the Rortor Losses on the IM Control

  • Pracoviště: Katedra elektrických pohonů a trakce
  • Anotace:
    The rotor resistance can change significantly depending on the mode of operation of the induction motor. It can influence the accuracy of the controller. This paper strives to analyze if it is important to respect the resistance change or not.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk