Sharif Digital Repository

The main objective of this a paper is to improve the efficiency of permanent magnet synchronous motors (PMSMs) by using an improved direct torque control (DTC) strategy. The basic idea behind the proposed strategy is to predict the impact of a small change in the stator flux amplitude at each sampling period to decrease electrical loss before the change is applied. Accordingly, at every sampling time, a voltage vector is predicted and applied to the machine to fulfill the flux change. The motor drive simulations confirm a significant improvement in efficiency as well as a very fast and smooth response under the proposed strategy  

Although permanent magnet synchronous motors (PMSMs) are inherently of high efficiency, their efficiency is enormously dependent on their control strategy. The purpose of this paper is to improve the efficiency of PMSMs under a direct torque control (DTC) method. The main idea behind the proposed method is to predict a required small change of the statorflux amplitude at each sampling period to reduce the machine electrical loss before the change is applied. Accordingly, at every sampling time, a voltage vector is predicted and applied to the machine to change the flux amplitude in a xvay that the electrical loss decreases. The results of simulation show significant improvement in the... 

Permanent magnet synchronous motor (PMSM) drives have many advantages over other drives, i.e. high efficiency and high power density. Particularly, PMSMs are epoch-making and are intensively studied among researchers, scientists and engineers. This paper deals with a novel high performance controller based on genetic algorithm. The scheme allows the motor to be driven with maximum torque per ampere characteristic. In this paper assuming an appropriate fitness function, the optimum values for d-axis current of motor set points at each time are found and then applied to the controller. Simulation results show the successful operation of the proposed controller  

Two major structures for rotor core of superconducting synchronous machine are air-cored and magnetic-cored structures. Magnetic-cored structure can be divided into two categories including salient and non-salient magnetic core. In this paper, three different structures of superconducting synchronous machine comprising air-cored, non-salient magnetic-cored and salient magnetic-cored, have been studied and compared considering required superconducting wire and machine weight. Required superconducting wire determines the capital cost and the weight of the machine determines the running cost in the case of portable applications such as ships and aircrafts  

High-efficiency Permanent Magnet Synchronous Motors (PMSMs) are widely used in industry. Subsequently, resolvers' employment is increasing in the drive of PMSMs. Measuring the rotor angle using a resolver needs a costly Resolver to Digital Converter (RDC). Therefore, a low-cost analog RDC is designed against the conventional Angle Tracking Observers (ATOs) in the following study. The designed RDC has satisfactory accuracy, simplicity, and enduring against excitation frequency. Firstly, an overview of the resolver is shown, and subsequently, the circuit of the designed RC is described thoroughly. Ultimately, the simulations' outcomes are displayed, and comparing our design with others... 

The main purpose of this paper is to minimize the loss while reducing the flux and torque ripples in permanent magnet synchronous motors (PMSMs) under direct torque control (DTC). Offline method is used to minimize the loss and obtain the optimal flux. To reduce the amount of computation, the optimal flux table is produced according to the conditions in which the machine works. To reduce the flux and torque ripples and to control the switching frequency, SVM-DTC method is applied. Simulation results depict a noticeable increase in efficiency of the motor and a reduction in flux and torque ripples  

Permanent magnet synchronous motor (PMSM) drives have many advantages over other drives, e.g. high efficiency and high power density. Particularly, permanent magnet synchronous motors are epoch-making and are intensively studied among researchers, scientists and engineers. This paper deals with a novel high performance controller based on genetic algorithm. The scheme allows the motor to be driven with maximum torque per ampere characteristic. In this paper assuming an appropriate fitness function, the optimum values for d-axis current of motor set points at each time are found and then applied to the controller. Simulation results show the successful operation of the proposed controller. ©... 

Resolver is an electromagnetic position sensor typically used in the closed-loop control of permanent magnet synchronous motors (PMSMs). In terms of structure and principle of operation, resolvers are very similar to electrical machines. In this regard, different numerical and analytical models have been developed for the performance prediction of a resolver, with a compromise between computational burden and accuracy. Therefore, a fast and accurate hybrid model of the resolver is presented in this article, which can be used for resolvers with different structures. Additionally, this model can easily be implemented in software such as MATLAB/SIMULINK. The performance of different variable... 

Control of Synchronous Motors at low speed has been the topic of several studies for the last years. Due to the lower amplitude of Back-EMF voltage in lower speed, it is inappropriate to merely rely on induced voltages for position estimation. In this paper, a new double carrier PWM modulation is presented in which two carrier frequencies are utilized for two legs of the inverter. This proposed method rectify the need of powerful processors which decreases the cost of the electric drive system. Employing a non-linear control system and an automatic gain control, ensures the sensorless control of the motor for a wide range of speed. © 2019 IEEE  

The study reported in this paper deals with the problem of developing a controller with tolerance to current sensor faults. To achieve this goal, two control strategies are considered. In the first method, field oriented control and a developed observer are used in case of no fault. The second approach is concerned with fault tolerant strategy based on an observer for faulty conditions. Current sensors failures are detected and the current will be estimated successfully in order to allow continuous operation of the vector control. Based on the motor model, currents can be estimated using a nonlinear observer. A decoupling current vector control strategy is developed to ensure high... 

A superconducting synchronous motor with an inductor containing bulk high temperature superconductor and BiSrCaCuo wires has been studied in this paper. The principle of operation is based on the interaction between the two spatial variable magnetic fields in the motor air gap. One of the two aforementioned magnetic fields is produced by the superconducting inductor based on magnetic shielding of high temperature superconductors. A procedure is developed to calculate the magnetic field produced by the inductor in the environment of the commercial finite element code ANSYS. The HTS motor is designed to develop 100 hp (the rated power). © 2008 Australasian Universities Power Engineering... 

Since any error in the rotor angle caused by the resolver affects the entire permanent magnet synchronous motor (PMSM) control drive system, it is necessary to investigate its effect on mechanical vibrations. Torsional vibration is accordingly considered in the following study. Thereby, first, the effect of resolver errors on the harmonic content of motor current and, subsequently, torque ripple (TR) was investigated. Then, dynamical modeling is done for the generator-motor-resolver set to get the mechanical frequency response (FR) resulting from the resolver errors. Based on the above modeling, the dynamic equations (DEQs) of the system were derived, and the mechanical characteristics of... 

High-efficiency Permanent Magnet Synchronous Motors (PMSMs) are widely used in industrial applications. Subsequently, resolvers as position sensors experience increasing usage in the drive of PMSMs. Measuring the rotor's position using a resolver needs a costly Resolver to Digital Converter (RDC). Therefore, in this paper, a software-based, low-cost RDC is presented against the conventional Angle Tracking Observers (ATOs). The proposed RDC is a high-Accuracy two-stage Deep Neural Network (DNN)-based one. In this regard, an overview of the resolvers' function and the general methodology to DNN training is given. Then, the case study is done on the gathered data from the set of the resolver... 

This paper describes a control scheme that allows an IPMS motor drive system to operate in the event of current and speed sensor faults. This task can be achieved by two control strategies: a nominal performance controller and a fault detection part. The nominal controller combines field oriented control and addresses fault tolerance scheme. Fault-tolerant strategy will operate in parallel with the system until a fault is detected. This approach is based on the adaptive backstepping observer. Stator resistance as possible source of system uncertainty is taken into account under different operating conditions. Sensors failure are detected and developed observer is used to estimate currents... 

The combination of direct torque control and permanent magnet synchronous motors (PMSMs) provides a highly dynamic drive. In this paper direct torque control method of PMSM is merged with a sensorless control algorithm and a robust flux observer is proposed which results in a high performance highly reliable drive. First a high frequency signal injection method within DTC algorithm is introduced to estimate the rotor position of PMSM. Then the method is modified in order to estimate stator dynamic inductances. The stator inductances are then used in a current model flux observer  

Direct drive motors have the excellent ability for precision position control due to their direct connection to load and elimination of the gearbox and pulley backlash. Among the direct drive motors, permanent NdFeB magnet synchronous motors (PMSMs) are the best choice for control systems due to their high efficiency, high power density, good dynamic behaviour, and excellent controllability. This study deals with the design, analysis, and fabrication of a direct drive PMSM for precision position control. To reach this aim, the designed motor should have very low cogging torque and torque ripple to avoid the motor deviation at the target point. To achieve these purposes, at first, a suitable... 

Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is... 

An integrated procedure for mathematical modeling and power control balance for a SPA (Split Parallel Architecture) hydraulic hybrid vehicle is presented in this paper. Dynamic mathematical model of the powertrain is constructed firstly, which includes five modules: diesel engine, traction motor, starter, loading pump and accumulator. Based on the mathematic model of control modes a stability analysis is done. For some control modes a Sliding Mode Control is designed, which uses full-states closed-loop feedback. The paper finally illustrates and discusses the results of simulation. The results show that the performance and stability of control modes are proper and a power control strategy...