Direct Torque Control of BLDC Motor with Constant Switching Frequency

Direct torque control (DTC) has become a popular technique for brushless motor control because it provides fast dynamic torque response. Hysteresis band control is the most popular techniques used in the DTC BLDC motor drive caused the simplest technique. However the conventional DTC have problems as switching frequency that varies with operating conditions and high torque ripple. This paper presents direct torque control (DTC) of BLDC motor with constant switching frequency torque controller. The torque ripple will get reduced by this method constant switching frequency operation. The feasibility of this method in minimizing the torque ripple is verified through some simulation results

Performance Evaluation of Conventional Inverters Driven PMSM Drive using Microcontroller

This paper focues on Performance evaluation of conventional inverters driven PMSM drive using microcontroller. The purpose of this paper is to decrease the ripples in torque of Micro controllers based PMSM drive. The innovative method consists of conventional inverters, switched-mode power supply (SMPS), PMSM motor and Microcontroller. It is used to maximize fundamental component of torque also. The both the results of the suggested Micro controller are compared on the basis of torque and speed and improves that reduces the torque ripple and improve the dynamic response of the system in comparative analysis. This paper organizes introduction, mathematical model of the PMSM, proposed Microcontroller technique, hardware and simulation results and conclusion in different sections

Failsafe Innovative Electromechanical Actuator with Advanced Electric Motor Control Technique Against Single Point of Failure

Electromechanical actuators (EMAs) begin to have a greater presence in current aeronautic designs due to the energy efficiency and reliability advantages they can provide. However, the conventional mechanical design with a single combination of a ball screw and an electric motor is subject to scenarios in which a single point of failure can render it inoperative. This paper presents a failsafe innovative EMA that gives a solution to the most typical jamming issues of aeronautical electromechanical actuators, either due to ball screw or electric motor failures. Different electric motor synchronization techniques applicable to the presented mechanical EMA design are analysed, and the benefits of the most adequate control strategy, the virtual line-shafting (VLS), are validated. Finally, the implementation of the control algorithm in a simplified virtual test bench with promising results is shown. The obtained results demonstrate that the proposed novel EMA mechanical design can enhance the failsafe capabilities of the current EMA designs based on a single ball screw and motor combination.The project leading to these results has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under Grant Agreement no. 755562

On extended Kalman filters with augmented state vectors for the stator flux estimation in SPMSMs

The demand for highly dynamic electrical drives, characterized by high quality torque control, in a wide variety of applications has grown tremendously during the past decades. Direct torque control (DTC) for permanent magnet synchronous motors (PMSM) can provide this accurate and fast torque control. When applying DTC the change of the stator flux linkage vector is controlled, based on torque and flux errors. As such the estimation of the stator flux linkage is essential. In the literature several possible solutions for the estimation of the stator flux linkage are proposed. In order to overcome problems associated with the integration of the back-emf, the use of state observers has been advocated in the literature. Several types of state observers have been conceived and implemented for PMSMs, especially the Extended Kalman Filter (EKF) has received much attention. In most reported applications however the EKF is only used to estimate the speed and rotor position of the PMSM in order to realize field oriented current control in a rotor reference frame. Far fewer publications mention the use of an EKF to estimate the stator flux linkage vector in order to apply DTC. Still the performance of the EKF in the estimation of the stator flux linkage vector has not yet been thoroughly investigated. In this paper the performance of the EKF for stator flux linkage is studied and simulated. The possibilities to improve the estimation by augmenting the state vector and the consequences of these alterations are explored. Important practical aspects for FPGA implementation are discussed

Comparative performance study of alternate fault-tolerant inverter configurations for direct torque control-based three-phase PM BLAC drives under single-phase open-circuit fault

This paper presents a comparative performance study of three typical fault-tolerant control (FTC) topologies [split-capacitor (SC), extra-leg split-capacitor (ELSC), and extra-leg extraswitch (ELES)] for direct torque control (DTC)-based threephase permanent magnet (PM) brushless AC (BLAC) drives under single-phase open-circuit fault (SOF). The advantages and limitations of these FTC schemes are theoretically compared and empirically validated. To achieve reliable postfault operations, control issues associated with VM-based flux estimators employed for DTC-based BLAC drives under SOF are demonstrated and relevant remedies are proposed. It is shown that although the ELES scheme can maintain the normal based speed, 6 of its 8 switching states cause phaseto-neutral short circuit in one or both two remaining phase windings resulting in high current harmonic values. Besides, during its implementation, the full DC-link voltage value is always applied to the non-short circuit phase windings leading to high possibility of winding insulation damage. Thus, for a compromise of the normal based speed by a factor of 3/2 , the ELSC drive should be used to avoid these issues. Furthermore, in the low-speed region up to half of the rated speed, the lowest copper loss, current harmonics, and torque ripples can be obtained by utilizing the SC drive

Contribution to the Artifical Neural Network Speed Estimator in a Degraded Mode for Sensor-Less Fuzzy Direct Control of Torque Application Using Dual Stars Induction Machine

Recently one of the major topic of research is the involvement of the intelligence artificial in the control system. This paper deals with application of a new combination between two-control strategy known as fuzzy direct control of torque and then an adaptive Neuronal Speed estimator utilizing dual starts induction motor. The research discussed consist to replace the switching table used in the conventional direct control method and adaptive mechanism of the classic MRAS estimator with fuzzy controller and new neural network accordingly, both strategies can manage the degraded and normal modes. The neural networks used are the back-propagation, to reduce the training patterns and increase the execution speed of the training process. As results we achieved can be summarised as follows: 1) high degree of reliability of speed estimation even with using only one start voltages and currents and parameters; 2) Minimization of the torque and flux ripples; and                3) Minimization of the current total harmonic distortion

Fixed Switching Period Discrete-Time Sliding Mode Current Control of a PMSM

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksA fixed switching period sliding mode control (SMC) for Permanent Magnet Synchronous Machines (PMSMs) is presented. The aim of the paper is to design a SMC that improves the traditional PI based Field Oriented Control (FOC) transient response, as well as to reduce the switching frequency variations of the Direct Torque Control (DTC). Such SMC requires a decoupling method of the control actions, which also brings constant switching functions slopes. These constant slopes allow to calculate the required hysteresis band value to control the switching frequency. The digital implementation degrades the performance of the hysteresis comparator and as a consequence, the previously calculated band becomes inaccurate to regulate the switching frequency. In order to recover the analogue hysteresis band comparator performance, a predictive algorithm is proposed. Finally, a set of experimental results with constant switching frequency during a torque reversal and speed control tests are provided.Peer ReviewedPostprint (author's final draft