Kamil Antoniewicz, Krzysztof Rafal and Marek Jasinski
This paper presents a control method for a four-leg three-level flying capacitor converter (FCC) operating as a shunt active power filter (SAPF), based on model predictive control with finite number of control states (FS-MPC). Current control and capacitor voltage balancing are described. Influence of the mismatch of the inductive filter model parameters on the current control precision is analysed. Results are supported by the experimental waveforms obtained with a 10kVA set-up.
Krisztián Horváth and Márton Kuslits
This paper presents an estimator-based speed sensorless field-oriented control (FOC) method for induction machines, where the state estimator is based on a self-contained, non-linear model. This model characterises both the electrical and the mechanical behaviours of the machine and describes them with seven state variables. The state variables are estimated from the measured stator currents and from the known stator voltages by using an estimator algorithm. An important aspect is that one of the state variables is the load torque and, hence, it is also estimated by the estimator. Using this feature, the applied estimator-based speed sensorless control algorithm may be operated adequately besides varying load torque. In this work, two different variants of the control algorithm are developed based on the extended and the unscented Kalman filters (EKF, UKF) as state estimators. The dynamic performance of these variants is tested and compared using experiments and simulations. Results show that the variants have comparable performance in general, but the UKF-based control provides better performance if a stochastically varying load disturbance is present.
Xueqing Wang, Zheng Wang, Wei Wang and Ming Cheng
To improve the reliability of motor system, this paper investigates the sensor fault diagnosis methods for T-type inverter-fed dual three-phase permanent magnet synchronous motor (PMSM) drives. Generally, a T-type three-level inverter-fed dual three-phase motor drive utilizes four phase-current sensors, two direct current (DC)-link voltage sensors and one speed sensor. A series of diagnostic methods have been comprehensively proposed for the three types of sensor faults. Both the sudden error change and gradual error change of sensor faults are considered. Firstly, the diagnosis of speed sensor fault was achieved by monitoring the error between the rotating speed of stator flux and the value from speed sensor. Secondly, the large high-frequency voltage ripple of voltage difference between the estimated voltage and the reference voltage was used to identify the voltage sensor faults, and the faulty voltage sensor was determined according to the deviation of voltage difference. Thirdly, the abnormal current amplitude on harmonic subspace was adopted to identify the current sensor faults, and the faulty current sensor was located by distinguishing the current trajectory on harmonic subspace. The experiments have been taken on a laboratory prototype to verify the effectiveness of the proposed fault diagnosis schemes.
Mateusz Korzonek and Teresa Orłowska-Kowalska
This paper deals with the stability problem of three stator current error-based estimators of induction motor speed, especially in the regenerating operation mode. The stability of the adaptive full-order observer (AFO) and two model reference adaptive systems (MRASs) based on a stator current error (MRASCC and MRASCV) is briefly analysed, and the stability borders are determined and compared. It is shown that MRASCV speed estimator is stable in the whole operation range including the regenerating mode without any modifications. The stability enhancement method for AFO and MRASCC estimators is described, and the solution for their stability improvement is proposed. Torque-speed characteristics of the analysed MRAS-type estimators in a wide range of drive speed and load torque changes are given, as well as the behaviour of estimators during transients is compared. The theoretical analysis and simulation test results are validated by experimental tests.
This paper presents the direct field-oriented control (DFOC) method of six-phase induction motor with the application of super-twisting sliding mode algorithm. The mathematical model of the six-phase induction motor has been described. The descriptions of the space vector modulation (SVM) method and the super-twisting algorithm have been presented. The DFOC method with super-twisting sliding mode controllers has been described. The experimental studies of the DFOC method with super-twisting controllers have been performed, and the results of these studies are presented and discussed.
Jakub Hachlowski and Robert Stala
This paper presents a novel concept of a circuit for voltage balance of three series-connected capacitors or batteries, as well as the research results. The problem is related to the control of voltage sharing on series capacitors, supercapacitors or battery banks in energy storage systems or direct current (DC)-link of four-level neutral–point-clamped inverters. The proposed circuit is a switched-capacitor (SC) resonant converter composed of a single capacitor and seven transistor switches. Control of the converter makes it possible to transfer energy between any capacitors, by switching selected transistors. This paper presents the basic concept of the converter, an analysis of control strategies and the simulation results for various cases of voltage balancing.
In the paper, the concept of universal speed and flux estimator with additional parameters estimators is presented. Proposed solution is based on the Model Reference Adaptive System (MRAS) type flux and speed estimator and can be used in different industrial systems (especially in the automotive applications). Induction Motor (IM) parameters are estimated using the systems based only on simple simulators and adaptive systems (voltage model and current model). Proposed system was tested in the sensorless induction motor drive with the Direct Field Oriented Control (DFOC) algorithm. Simulation and experimental results are presented in the paper.
The purpose of the article was to present the idea of space vector pulse width modulation (SVPWM) and implementation in Nios II softcore processor. The SVPWM module was described in a classical method in hardware description language both as an independent structure and as an additional component to softcore processor. The available methods were compared, and the experiment was carried out in the laboratory to test implemented SVPWM algorithm using high-speed induction motor.
Tomasz Tarczewski, Michal Skinski, Lech M. Grzesiak and Marek Zieliński
The article presents modern PMSM servo-drive with SiC MOSFETs power devices and microprocessor with ARM Cortex core. The high switching frequency is obtained due to the application of high efficient power switching components and powerful microprocessor. It allows to achieve good dynamical properties of current control loop, proper disturbance compensation and silent operation of servo-drive. Experimental tests results obtained for two different control schemes (i.e., cascade control structure and state feedback position control) are presented.