An improved FPGA implementation of direct torque control for induction machines

This paper presents a novel direct torque control (DTC) approach for induction machines, based on an improved torque and stator flux estimator and its implementation using Field Programmable Gate Arrays (FPGA). The DTC performance is significantly improved by the use of FPGA, which can execute the DTC algorithm at higher sampling frequency. This leads to the reduction of the torque ripple and improved flux and torque estimations. The main achievements are: i) calculating a discrete integration operation of stator flux using backward Euler approach, ii) modifying a so called non-restoring method in calculating the complicated square root operation in stator flux estimator, iii) introducing a new flux sector determination method, iv) increasing the sampling frequency to 200kHz such that the digital computation will perform similar to that of the analog operation, and v) using two’s complement fixed-point format approach to minimize calculation errors and the hardware resource usage in all operations. The design was achieved in VHDL, based on a Matlab/Simulink simulation model. The Hardware-In-the-Loop (HIL) method is used to verify the functionality of the FPGA estimator. The simulation results are validated experimentally. Thus, it is demonstrated that FPGA implementation of DTC drives can achieve excellent performance at high sampling frequency

An Improved FPGA Implementation of Direct Torque Control for Induction Machines

This paper presents a novel direct torque control (DTC) approach for induction machines, based on an improved torque and stator flux estimator and its implementation using field-programmable gate arrays (FPGA). The DTC performance is significantly improved by the use of FPGA, which can execute the DTC algorithm at higher sampling frequency. This leads to the reduction of the torque ripple and improved flux and torque estimations. The main achievements are: 1) calculating a discrete integration operation of stator flux using backward Euler approach; 2) modifying a so called nonrestoring method in calculating the complicated square root operation in stator flux estimator; 3) introducing a new flux sector determination method; 4) increasing the sampling frequency to 200 kHz such that the digital computation will perform similar to that of the analog operation; and 5) using two’s complement fixed-point format approach to minimize calculation errors and the hardware resource usage in all operations. The design was achieved in VHDL, based on a MATLAB/Simulink simulation model. The Hardware-in-the-Loop method is used to verify the functionality of the FPGA estimator. The simulation results are validated experimentally. Thus, it is demonstrated that FPGA implementation of DTC drives can achieve excellent performance at high sampling frequency

High-Speed Computation using FPGA for Excellent Performance of Direct Torque Control of Induction Machines

The major problems in hysteresis-based DTC are high torque ripple and variable switching frequency. In order to minimize the torque ripple, high sampling time and fast digital realization should be applied. The high sampling and fast digital realization time can be achieved by utilizing high-speed processor where the operation of the discrete hysteresis regulator is becoming similar to the operation of analog-based comparator. This can be achieved by utilizing field programmable gate array (FPGA) which can perform a sampling at a very high speed, compared to the fact that developing an ASIC chip is expensive and laborious

Agricultural Management through Wireless Sensors and Internet of Things

Agriculture plays a significant role in most countries and there is an enoromous need for this industry to become “Smart”. The Industry is now moving towards agricultural modernization by using modern smart technologies to find solutions for effective utilization of scarce resources there by meeting the ever increasing consumtion needs of global population. With the advent of Internet of Things and Digital transformation of rural areas, these technologies can be leveraged to remotely monitor soil moisture, crop growth and take preventive measures to detect crop damages and threats. Utilize artificial intelligence based analytics to quickly analyze operational data combined with 3rd party information, such as weather services, expert advises etc., to provide new insights and improved decision making there by enabling farmers to perform “Smart Agriculture”. Remote management of agricultural activities and their automation using new technologies is the area of focus for this research activity. A solar powered remote management and automation system for agricultural activities through wireless sensors and Internet of Things comprising, a hardware platform based on Raspberry Pi Micro controller configured to connect with a user device and accessed through the internet network. The data collection unit comprises a set of wireless sensors for sensing agricultural activities and collecting data related to agricultural parameters; the base station unit comprising: a data logger; a server; and a software application for processing, collecting, and sending the data to the user device. The user device ex: mobile, tablet etc. can be connected to an internet network, whereby an application platform (mobile-app) installed in the user device facilitates in displaying a list of wireless sensor collected data using Internet of Things and a set of power buttons. This paper is a study and proposal paper which discusses the factors and studies that lead towards this patent pending invention, AGRIPI

An FPGA-based controller for collaborative robotics

The use of robots is becoming more common in society. Industrial robots are being developed to work with people, and lower-force collaborative robots are being developed to help people in their everyday lives. These may need fast and sophisticated motion control and behavioral algorithms, but are expected to be more compact and lower cost. This paper proposes a processor plus FPGA solution for the control systems for such robots, where the FPGA performs all real-time tasks, freeing the processor to run lower-frequency high level control and interface to other devices such as camera systems. A demonstrator robot is designed, combining multi-axis motion control with 3D robot vision

Implemetasi Komputasi Akar Kuadrat Resolusi Tinggi pada Field Programmable Gate Array (FPGA)

Komputasi akar kuadrat diperlukan pada beberapa proses pengendalian, diantaranya untuk Direct Torque Control (DTC) pada sistem penggerak motor yang membutuhkan proses perhitungan yang sangat cepat. Field Programmable Gate Array (FPGA) merupakan salah satu perangkat yang dapat digunakan untuk implementasi komputasi yang memerlukan kecepatan dan presisi tinggi. Penerapan komputasi akar kuadrat pada FPGA menggunakan metode digit by digit non-restoring dengan beberapa modifikasi agar memiliki hasil perhitungan dengan nilai error yang kecil. Sistem tersebut diimplementasikan menggunakan 32-bit input dan 16-bit output. Proses perhitungan melibatkan Finite State machine (FSM) untuk menghemat resource yang diperlukan. Proses verifikasi sistem dilakukan dalam dua tahap, yaitu verifikasi fungsional dengan aplikasi ModelSim-Altera dan verifikasi hardware menggunakan modul FPGA Cylcone IV EP4CE6E228N. Hasil verifikasi menunjukkan bahwa hasil perhitungan akar kuadrat memiliki resolusi sampai dengan 0,0039. Selain itu, sistem ini membutuhkan 157 Logic Elements dan 120 register dengan kecepatan clock tertinggi yang dicapainya adalah 205 MHz untuk input 32 bit AbstractSquare root computing is required in several control processes, such as for Direct Torque Control (DTC) on motor drive systems that require a very fast calculation process. Field Programmable Gate Array (FPGA) is one of the devices that recommended for high speed and precision computation. The implementation of the square root on the FPGA uses the digit-by-digit non-restoring method with some modifications to get a high precision of computation result. The system is implemented using 32-bit input and 16-bit output. The calculation process involves a Finite State machine (FSM) to minimize computation resources. The system verification process is carried out in two stages, i.e. functional verification using the ModelSim-Altera and hardware verification using the FPGA Cylcone IV EP4CE6E228N. The verification shows that the result of the square root calculation has a resolution of up to 0.0039. In addition, the system requires 157 Logic Elements and 120 registers with the highest clock speed can achieves 205 MHz for 32-bit input

An Improved FPGA Implementation of Direct Torque Control for Induction Machines

This paper presents a novel direct torque control (DTC) approach for induction machines, based on an improved torque and stator flux estimator and its implementation using Field Programmable Gate Arrays (FPGA). The DTC performance is significantly improved by the use of FPGA, which can execute the DTC algorithm at higher sampling frequency. This leads to the reduction of the torque ripple and improved flux and torque estimations. The main achievements are: i)calculating a discrete integration operation of stator flux using backward Euler approach, ii) modifying a so called non-restoring method in calculating the complicated square root operation in stator flux estimator, iii) introducing a new flux sector determination method, iv) increasing the sampling frequency to 200kHz such that the digital computation will perform similar to that of the analog operation, and v) using two’s complement fixed-point format approach to minimize calculation errors and the hardware resource usage in all operations. The design was achieved in VHDL, based on a Matlab/Simulink simulation model. The Hardware-in-the-Loop (HiL) method is used to verify the functionality of the FPGA estimator. The simulation results are validated experimentally. Thus, it is demonstrated that FPGA implementation of DTC drives can achieve excellent performance at high sampling frequency

Advanced Non-Overlapping Winding Induction Machines for Electrical Vehicle Applications

This thesis presents an investigation into advanced squirrel-cage induction machines (IMs), with a particular reference to the reduction of the total axial length without sacrificing the torque and efficiency characteristics and analysis of recently found non-sinusoidal bar current phenomenon, which occurs under some certain design and operating conditions, and affects the overall performance characteristics of the IMs. As a first step, the most convenient method is determined by utilizing a fractional-slot concentrated winding (FSCW) technique, which has advantages such as non-overlapping windings, high slot filling factor, and simple structure. After implementing this technique, it is found that due to the highly distorted magnetomotive forces (MMFs) created by the FSCWs, significant high rotor bar copper loss occurs. In order to reduce the MMF harmonics without increasing the size of the machine, a new technique titled “adapted non-overlapping winding” is developed. This technique consists of the combination of the auxiliary tooth and phase shifting techniques, resulting in a stator with concentrated windings of two-slot coil pitches but without overlapping the end-windings. Thanks to this method a large number of the MMF harmonics are cancelled. Thus, a low copper loss IM with significantly reduced total axial length is obtained. Influence of design parameters; such as stator slot, rotor slot, and pole numbers, number of turns, stack length, stator and rotor geometric parameters, etc. on the performance characteristics of the advanced IM is investigated and a comprehensive comparison of advanced and conventional IMs is presented. This thesis also covers an in-depth investigation on the non-sinusoidal bar current phenomenon. It is observed that the rotor bar current waveform, usually presumed to be sinusoidal, becomes non-sinusoidal in some operation and design conditions, such as high speed operation close to synchronous speed, or fairly high electrical loading operation, or in the IMs whose air-gap length is considerably small, etc. Influences of design and operating parameters and magnetic saturation on the rotor bar current waveform and the performance characteristics of squirrel-cage IMs are investigated. The levels of iron saturation, depending on the design and operating parameters, in different machine parts are examined and their influences are also investigated, whilst the dominant part causing the non-sinusoidal rotor bar current waveform is identified. It is revealed that the magnetic saturation, particularly in the rotor tooth, has a significant effect on the bar current waveform