This chapter presents a design proposal for low-cost speed control and electrical fault mitigation of three-phase induction motors. The proposed system can control and monitor TIMs (three-phase induction motors) from far-flung areas. Here authors have proposed a relay-free system for fast fault clearance. IoT technology and low-cost microcontrollers have helped in achieving a system that is more reliable, economical, user friendly, and fast. It can be controlled by mobile application at the comfort of home. Data related to fault occurrence can be stored and analyzed for preventive maintenance. V/f scalar control method is used for speed control of TIM and able to control it in a wide range. Electrical faults such as over-current, over-temperature, over-voltage, and under-voltage are considered in this chapter. Simulation of the proposed design is done using Proteus 8 software. ESP32 is used to runs a web server that connects the mobile app with simulation.
TopIntroduction
In this industrial era, every type of industry requires and uses a three-phase induction motor (TIMs). These motors are predominant to other electrical motors due to their robustness, reliability, and economical availability. Some of its most predominant features such as self-starting and constant speed operation have made it industries most praise electrical machine. TIM’s various applications in the industry require speed controlling either in manufacturing unit or in-service unit. Some of its application is found in conveyors, refrigerators, pumps, wind tunnels, etc. A current belief indicates that the internet of things technology is leading the world towards the fourth industrial revolution. If smart-phones can control an electric bulb, then industrial motors can definitely be controlled with it besides monitoring its running condition. Protection of TIMs from various faults is another target of the proposed system. Since buying or repairing industrial workhorses i.e. TIMs further adds the industrial operational cost which is neither good nor feasible for any industry as it halts the manufacturing process. Losses due to the halting of TIMs include additional labor cost, service cost, per day goods manufacturing loss, additional monetary loss due to repairing, etc. In a study, it is found that out of all failures motor failure occurs 33% due to electrical fault, 31% due to mechanical fault, and 36% due to other factors such as environmental maintenance, etc.(Thomson, 2001). An Induction motor's health can be overseen by the health of its main components such as stator, rotor, and bearing. Here the authors have considered electrical faults. Faults like over-current, over-voltage, under-voltage, phase failure, over temperature are general electrical faults. These types of faults are commonly occurring in all industries which have variable load demand. Speed control and fault mitigation are two very important aspects with respect to industrial demand. The authors tried to amalgamate two systems into one and that too with minimizing the complexity of circuits. Another challenge was to make it cost-effective, technically advanced and operator friendly. For these purposes, IoT technology is used along with a low-cost microcontroller. It has converted the whole controlling process into a smart one. The fault mitigation system is relay-free as the inverter trips the motor when the microcontroller gave a fault occurrence signal to IGBT drivers and the gate pulse turned off. The whole system is simulated using software Proteus 8. The whole system is connected to the internet and controlled by a mobile application with the help of an ESP32 microcontroller.
Background
Several studies have been conducted on speed control of three-phase induction motor (Lüdtke, 1995). The primary goal is to control the rotational speed and maintain it too, at the instance of disturbances. Some of the high-performance speed control strategies are based on direct torque control and field orientation method (Lüdtke, 1995; Negm, 2006 ; Peña, 2016) but the V/f control method is also capable of high performances at low-speeds (Garcia,1998). Along with it, scalar V/f provides an easy as well as a practical way while controlling real-time TIMs (Seutake, 2011; Peña, 2016). This approach is best suitable for steady states. There are two types of the scheme in V/f control, i.e. Open-loop and closed-loop. The open-loop approach is commonly used due to simplicity, but closed-loop provides higher performance characteristics (Peña, 2016). Besides speed control, another important aspect for TIM is to give emphasis on fault condition too. Any faults if not addressed on time may lead to overall motor failure. Various studies show the ill effect of faults on TIM and the manufacturing industry (Sutar, 2017). Fault analysis and detection can be done by analyzing the current signature (Thomson, 2001). Real-time fault status analysis and mitigation can be easily done by using microcontrollers (Kunthong, 2017). Depending on the handling of these faults, one can predict the life cycle of the TIMs (IEEE S.A Standard board, 2016).
The IoT technology provides various advantages such as easy installation, low-cost solutions, and remotely upgradable software with alert notifications to operators (Goundar, 2015; Abid, 2020). ESP32 immerged as best solution for IoT application due to its swiftness, compactness and Low power consumption (Sharp, 2017).
Block Diagram And Flow Charts
Figure 1. The block diagram of proposed system