فهرست مطالب abolfazl halvaei niasar

In the drive control of permanent magnet synchronous motors (PMSMs), the control system must be designed to work in different conditions and against of changes in motor parameters and unknown disturbances. In order to enhance the drive performance of PMSM motor, the model-predictive control independent of current and speed model (MFPCSC) is proposed in this article. This method only uses the input and output of the system and does not involve the motor parameters in the drive control, and it is robust to the changes of the motor parameters. The conventional model-independent predictive control method requires setting several control parameters. To improve the performance of the drive system of this motor and make it robust to changes in parameters and disturbances, the proposed MFPCSC method is designed based on the nonlinear disturbance observer (NDO). This observer can estimate system disturbances with more accuracy and stability, and the amount of calculations is small. The simulation and practical test results of the proposed MFPCSC method combined with the NDO show that the proposed control method has high robustness to parameter changes, favorable transient response, small output ripple, and improved transient characteristics, and can accurately and stably estimate system disturbances.

Brushless DC motors called BLDC are used in many industrial and non-industrial applications today for reasons such as very high efficiency, easy control method and high reliability, and their use is increasingly used in mass production applications, especially home appliances. But these motors require the use of an electric drive, even in constant speed applications. Commercialization of these drives by reducing their price and increasing their reliability is one of the main goals of craftsmen and researchers. These goals have been achieved to some extent by using fewer power switches, reducing the number of current and voltage sensors, eliminating position sensors, and using sensorless control methods. But according to the electrolytic capacitors used to reduce DC voltage ripple are both significantly more expensive and, inherently, potentially cause the most damage to the drive. In this paper, with the aim of eliminating high-capacity electrolytic capacitor and using low capacity switched thin film capacitor in DC link, a new control method based on simultaneous control of speed and torque is presented, the use of which significantly causes torque ripple. Reduced voltage fluctuations in the DC link. The validity of the introduced method is checked using simulation in Simulink software and then a laboratory sample of the drive is tested and the results of theory and simulation are validated.

This study aims to report on the application of Linear Quadratic Integral (LQI) based global maximum power point tracker (GMPPT) method for transferring the available maximum power from photovoltaic (PV) systems to load in unshaded and shaded conditions. For the maximum power transmission under varying the environmental conditions and partially shaded conditions, MPPT technologies are utilized in PV systems. For the improvement of functioning MPPT, a new two-level control structure which decreases difficulty in the control process and efficiently deals with the uncertainties in the PV systems is introduced. In the proposed approach, the reference voltage at the global maximum power point (GMPP) is estimated by a new scanning algorithm. The difference between the reference voltage and the voltage of the PV array is then used by LQI controller to generate the duty cycle for a boost converter. The design process of the proposed approach is explained as step by step. The benefits of the approach are quicker tracking capability, transferring maximum deliverable power and simple implementation. To verify the proposed method, several irradiation profiles that create several peaks in the P-V curve are used. The simulation results show that the proposed method causes PV systems to track the GMPP immediately so that no oscillation around the GMPP is observed. Therefore, maximum efficiency can be derived from the PV system.

Evaporative coolers due to their low cost are used in hot and dry regions of many countries especially in Iran. Conventional evaporative coolers use single-phase induction motors (SPIMs). But the benefits of these motors are very low, and their substitution with high efficient electrical motors is considered by industrial parties. In this paper, the details of using the brushless motor in the application of evaporative cooler are presented. A 1/2 hp brushless motor and drive are designed and built. This motor- drive is tested by a dynamometer and standard testing equipment. Also, for the approval of this motor-drive, a 5000 m3/h direct evaporative water cooler equipped with this motor is examined under the airflow rate test in the reference laboratory. The results obtained in both tests are compared with the test results of a typical SPIM. The results verify an increase of at least 60% for energy efficiency compared to evaporative coolers equipped with SPIM. Moreover, a new control scheme based on power control instead of speed control is proposed to stabilize the outlet airflow rate. The results indicate that use of brushless motors in this application can offer considerable energy saving, and helps to protect environment.

Recently, the pulsed power and pulsed electric field systems used in various industries and these systems have found wide applications. For this reason, using the pulsed power generators that in addition to responding to the needs of the user, are providing the advantages of compactness, high flexibility, high repetition rate and cost efficiency is inevitable. In this paper a hybrid solid state pulsed power generator is introduced that is modular and very flexible. This converter which is a combination of Marx and capacitor diode voltage multiplier, is capable of producing high voltage pulses with varying amplitudes at different frequencies. This proposed converter due to having high reliability, low cost, low weight, and structure’s simplicity can cover a wide area of applications. In this paper after introducing the proposed topology, its analytical design is described and its verification is proved by the simulation results in MATLABSIMULINK and by presenting the measurement results taken from the experimental prototype in low voltages.

Evaporative coolers, as one of the least efficient and commonly used electrical power consumers, are used in different areas in Iran. Recent government agencies have focused on the improvement of this consumer by modifying motor designs or the replacement of the single-phase induction motors with higher-efficiency motors, such as brushless motors. The control method of brushless motor, used in this application, is often based on the speed control which is constant (for example, two speeds high and low). However, laboratory tests show that due to special characteristics of the cooler’s fan, the amount of air flow rate is not related to the fan speed alone. Commercial evaporative coolers are designed for a certain length of the channel that is able to deliver its nominal flow. Increasing the length of channel by the owner can reduce the airflow rate and practically, despite the paid cost, no good airflow rate can be achieved. To remedy this problem, a new approach is proposed in this paper to stabilize airflow rate. For this purpose, the motor, instead of using the constant speed control approach, is controlled in a constant power approach. The details of the requirement’s design, the application of brushless motor in the evaporative cooler, as well as the results of the test of a 0.5 hp (horse power) brushless motor using the dynamometer are presented.  The results are compared with the results of a typical single-phase induction motor test. Afterwards, a 5000 m3/h evaporative cooler, equipped with brushless motor, is tested in the reference laboratory under airflow test. The test is carried out both in a constant-speed and in constant-power control approaches. The achieved results indicate the absolute superiority of brushless motor over single-phase induction motors;also the constant power control method has a better performance in comparison with a constant speed method.

In this paper, an adaptive control method is proposed for maximum power point tracking (MPPT) in photovoltaic (PV) systems. For improving the performance of an MPPT, this study develops a two-level adaptive control structure that can decrease difficulty in system control and efficiently handle the uncertainties and perturbations in the PV systems and the environment. The first control level is a ripple correlation control (RCC), and the second level is a model reference adaptive control (MRAC). This paper emphasizes mainly on designing the MRAC algorithm, which improves the underdamped dynamic response of the PV system. The original state-space equation of PV system is time-varying and nonlinear, and its step response contains oscillatory transients that damp slowly. Using the extended state-dependent Riccati equation (ESDRE) approach, an optimal law of the controller is derived for the MRAC system to remove the underdamped modes in PV systems. A algorithm of scanning the P-V curve of the PV array is proposed to seek the global maximum power point (GMPP) in the partial shading conditions (PSCs). It is shown that the proposed control algorithm enables the system to converge to the maximum power point in milliseconds in partial shading conditions .

Due to low cost, evaporative coolers are used in most of the central regions and in the warm and dry climate of Iran and are considered as one of the major consumers of electrical power. Most evaporative coolers use single-phase induction motors by connecting directly to the power grid. But their eefficiency is very low, and their replacement with high efficiency electric motors is considered by government bodies. Today, the use of permanent magnet brushless motors has been considered in many industrial and home applications. In this paper, the details of using the brushless motors in the application of the evaporative cooler are presented and the requirements and standards for designing and manufacturing the brushless motor and its drive are stated. A 0.5 hp brushless motor and its drive are designed and built. This motor is tested by a dynamometer and standard testing equipment. Also, the 5000 m3h evaporative cooler equipped with this brushless motor is tested in the reference laboratory. The results obtained in both tests are compared with single-phase induction motor test results. The results demonstrate an increase of at least 60% energy consumption compared to evaporative coolers equipped to single-phase induction motors. Also, the economic considerations and extra cost of brushless motors and other technical considerations are discussed in this article. The results indicate that the use of brushless motors in this application can be a huge step in saving energy, protecting the environment and reducing the problems caused by electricity consumption in the country.

In this study an improved direct torque control method (DTC) for Axial-flux hysteresis motor speed controlling is investigated. Time-consuming and dangerously of the necessity to manually adjust the motor speed and voltage when motor lagging occurs are the main drawback of the conventional control methods. The proposed method under acceleration and sequential braking on the Axial-flux hysteresis motor, based on the extracted modified motor dynamic equations in the Simulink Matlab environment has been simulated. As the results show, by using the proposed direct torque control method, the speed of the motor in the consecutive acceleration and braking process is controlled and the referral speed throughout the process operation with high accurate has been followed. Also this control system has shown that it is reliable method and stable against disturbances. Compared with conventional vector control methods, less complexity, higher speed and accuracy and easier implementation ability are significant features of the proposed method.

Hysteresis motors are used in special applications such as gyroscope, centrifuge, and machine tool spindle drives due to their unique features such as synchronism, self-starting and developing smooth torque. Dynamic modeling of hysteresis motors is essential to predict of the transient performance, studying the dynamic stability and development of modern closed-loop control and estimation strategies. This paper develops a new dynamic modeling for a high-speed, circumferential-flux type hysteresis motor in synchronous dq reference frame. Major previous models use fixed parameters for rotor’s equivalent circuit parameters corresponding to the major B-H loop of rotor material, whereas operational B-H loop is significantly affected by stator voltage and load torque. In this paper, a time varying dynamic model is developed, in which the parameters of the equivalent circuit of hysteresis rotor material are adjusted based on operational B-H loop. For this purpose and based on elliptical assumption for B-H loops, the hysteresis lag angle β is updated due to the applied stator voltage and available load torque. Developed mathematical model satisfies many theoretical aspects of hysteresis motor behavior in transient and steady-state situations. The model offers a tool for studying the start-up of hysteresis motor, change of stator voltage, variation of load torque, frequency tracking for variable-speed applications and transient-state response to design parameters. Some simulations are provided to demonstrate the validity of developed model in Matlab/ Simulink environment and are verified via some experimental results. Proposed results verify the advantages of this model rather than previous works.

In this paper a novel power management method for an electric vehicle (EV) equipped with two energy storage systems is presented. In this way, an optimized nonlinear controller based on fuzzy system is developed. The main stage to design a fuzzy controller is proper determination of fuzzy rules and membership functions that in this paper, the fuzzy rules and input and output membership functions of fuzzy controller are determined via mixed integer genetic algorithm (GA). The model of EV and optimized fuzzy controller as well as conventional fuzzy controller and optimized on/off controller are simulated in ADVISOR environment for the standard driving cycle EPA urban UDDS. Simulation results confirm a significant reduction in the consumed energy by the proposed optimal fuzzy controller in comparison with the conventional fuzzy and optimized on/off controllers.

Nowadays, internal combustion vehicles are the main reason of air pollution in urban areas. Reducing the emissions, energy optimization, and fuel economy are the main goals of vehicle manufacturers. Design and development of clean vehicle including electric vehicles (EVs), hybrid electric vehicles (HEVs), and fuel cell vehicles (FCVs) are the mid and long term strategies to capture the above goals. Unfortunately, these technology in spite of development the clean vehicles in advanced countries, are not the objectives in our country. This paper in order to develop of hybrid electric vehicle technology and using the available resources in Iran, proposes the design and manufacturing steps of the first HEV based on Pride platform. Hybrid Prides that is named Shaheb2 has been manufactured by a joint group student of electrical and mechanical engineering at University of Kashan and prepared for third national competition for manufacturing of hybrid vehicles. Due to some cost and time limitations, Trough-To-Road (TTR) or separated-axle parallel hybrid electric vehicle topology has been chosen. Internal combustion engine of Shaheb2 is 1300CC engine of Pride vehicle that as well as mechanical transmission components such as gearbox, differential are implemented on the front axle. Electric propulsion including electric motor (EM) and drive, energy storage system are located on the rear axle. Employed EM is a 22 kW PMSM that is controlled via field oriented scheme based on space vector modulation inverter and works in two modes torque control and speed control. To store of electrical energy, a set of Li-Ion-Polymer batteries with 192 dc volt has been used. To have an optimum performance for the vehicle, Hybrid Control Unit (HCU) has been developed in which the vehicle can work in different modes only motor, only engine, hybrid and regenerative braking. Employed control method in HCU is based on On/Off strategy that has been implemented by using AVR microcontroller. Due to extra weight of electric propulsion system and so the change of center of mass and total weight of the vehicle, and to increase the stability of the vehicle, the vehicle’s chassis has been enforced and the results have been confirmed via finite element analysis in ANSYS. Suspension system and other auxiliary systems of the vehicle have been recalculated and verified. Aerodynamic performance of the vehicle’s body has been analyzed in Gambit and Fluent and some changes have been made on the body.

Nowadays, due to significant increase in demands of electric motors for residential, commercial and industrial applications, and for optimum consumption of electrical energy, the design and manufacturing of high efficiency motors and related variable speed drives have been regarded by many suppliers. Among several kinds of motors, the brushless DC (BLDC) motor is employed in many applications due to its high efficiency, high power and torque density, and ease in control, simple fabrication, high reliability, and lower maintenance. This motor is similar to PMSM in construction, while is controlled as easy as of DC motor. This paper to help for development and employing BLDC motors, reviews the different aspects of BLDC motors including performance, modeling, employed inverters, assessment of control methods for BLDC motor and implementation of its drive. Advantages and disadvantages of different control methods, remarks on various position sensorless methods, the effectiveness of various minimization schemes for commutation torque ripple, and control of BLDC motor in constant power region or flux-weakening are described in more details. Finally, some practical points are suggested for manufacturing of a commercial BLDC motor drive.

This paper proposes the design of a nonlinear optimal controller for a submarine with nonlinear model with six degrees of freedom (6-DOF). The control aims includes achieving system stability، reaching the submarine to a desirable point at the end of the maneuver، and choosing the optimal path that are accessible by solution of optimal cost function. The novelty of this paper is the systematic step selection in the gradient descent algorithm that has increased the rate of convergence beyond two times rather than fixed step algorithm. Finally، via some simulations، the robust performance of the designed controller for moving in different depths with considering of parametric uncertainty has been confirmed.

Hybrid electric vehicles (HEV) in addition to provide the benefits of electric vehicles could satisfy consumers for some performances of conventional internal combustion engine (ICE) vehicles such as acceleration and long range. On this way, suitable energy optimization strategies should be employed to get desired efficiency, less fuel consumption and pollution. One of the favorite and simple configurations of HEVs is parallel type. A student team at University of Kashan, IRAN have designed and manufactured Shaheb 2 hybrid electric vehicle. It is a separated-axle (or Through-to-Road (TTR)) parallel HEV type based on Pride platform. Employed energy management in Shaheb 2 is on/off strategy and three modes; motor, engine and hybrid have been implemented. This paper investigates the modeling of separated-axle (or TTR) parallel type of HEV in ADVISOR software and then evaluates two control strategies for Shaheb 2; on/off strategy and an intelligent control based on fuzzy logic. On this way, maximizing the engine is considered as objective function. The simulation results indicate that the fuzzy strategy leads to less fuel consumption and lower pollution for given UDDS driving cycle rather than on/off strategy for Shaheb 2.

In this paper a new method for speed control of BLDC motors is proposed. In this method، fractional order PID (FOPID) is used for control of BLDC motor. In order to determine the parameters of FOPID controller imperialist competitive algorithm (ICA) is employed for its high speed and accurate for solve of optimization problems. In order to verify the performance of proposed controller، some simulations have been carried out with different object functions in Simulink environment of MATALB and obtained results have been compared with results of conventional PID. Good performance of proposed controller is validated by results of simulations.