COMPARATIVE ANALYSIS OF CONTROL SYSTEMS FOR A VOLTAGE SOURCE INVERTERS FOR AC DRIVES

The brief survey of electric drives implicated in both industry and transport are carried out. The results of comparison of control systems of a voltage source inverters included in an electric drive system with an asynchronous or synchronous motor are presented. The results were obtained by means of Matlab.

Speed control in DC and AC drives

<div><span lang="EN-US">Three speed-control strategies for DC and AC drives are presented in this study: a proportional<strong> </strong>integral derivative (PID) control strategy; an internal model control (IMC); and a state-space control by pole assignment with full state observer (ESSO). The three strategies are applied to a case study, demonstrating the potential of each one. Experimental identification was used to obtain the drive models used for the synthesis of the controllers. The three strategies showed satisfactory results when compared with the requirements imposed on the system, in addition to the good rejection of disturbances. However, the IMC strategy showed itself to be a little softer and with no maximum overshoot, which in some cases and some applications is usually a restriction.</span></div>

Condition Monitoring and Feature Extraction of Stator Current Phasors for Enhanced Fault Diagnosis in AC Drive

AC drives are employed mainly in process plants for various applications. In most industrial applications, Induction motor drives are preferred as they are robust, reliable, and efficient. Process industries have seen a paradigm shift from manual control to automatic control. Advancements in power electronics technology have led to smooth control of the induction motor using variable frequency drives over an entire speed range. Variable Frequency Drives (VFD) comprises of Voltage source inverter and a three phase squirrel cage induction motor. Various electric faults that are incipient in the VFD cause an abrupt change in circuit parameters resulting in insulation damage, reduced efficiency, and leading to catastrophic failure of the entire system. Hence, continuous monitoring of the system parameters such as stator current, speed, and the vibration of the machine is essential to diagnose incipient faults in the system. AI techniques have been effectively used in the fault diagnosis of electrical systems. In the proposed work, simulation results of machine learning-based fault diagnosis techniques are presented. Real-time IoT-based condition monitoring of the Variable Frequency Drive is also implemented for enhanced fault diagnosis of various incipient electrical faults in AC drives. The experimental results obtained are validated with the simulation data.

Penerapan Teknologi Mesin AC Mobil Bagi Siswa Jurusan Teknik Otomotif Di SMK Negeri 1 Losarang

Completeness praktikun learning tool in achieving competence automotive field would be a necessity that must be met. Seeing the large number of students at SMKN 1 Losarang, majoring in Automotive engineering, having practicum facilities that are still relatively minimal, with the limited practical facilities, additional practical facilities are needed in the form of car AC machine trainers to improve student competence at SMK N 1 Losarang. Increased competence by providing trainer AC Drives and conducted training and workshops and provide free test and post-test were conducted before and after the training. With the application of AC engine technology competence of students majoring in Automotive cars increased by 20.5%. This is based on comparison of the value of the free test to post-test value that has been done. PKM activity carried out has an impact enough for both students and the school's own department.

Machine learning based multi class fault diagnosis tool for voltage source inverter driven induction motor

AC drives are employed in process industries for varying applications resulting in a wide range of ratings. The entire process industry has seen a paradigm shift from manual to automated systems. The major factor contributing to this is the advanced power electronics technology enabling power electronic drives for smooth control of electric motors. Induction motors are most commonly used in industries. Faults in the power electronic circuits may occur periodically. These faults often go unnoticed as they rarely cause a complete shutdown and the fault levels may not be large enough to lead to a breakdown of the drive. An early detection of these faults is required to prevent their escalation into major faults. The diagnostic tool for detection of faults requires real time monitoring of the entire drive. In this work, detailed investigation of different faults that can occur in the power electronic circuit of an industrial drive is carried out. Analysis and impact of faults on the performance of the induction motor is presented. A real time monitoring platform is proposed to detect and classify the fault accurately using machine learning. A diagnostic tool also is developed to display the severity and location of the fault to the operator to take corrective measures.

A novel digital modulation scheme for multilevel cascaded H-bridge inverters in high power AC drives

The multilevel cascaded H-bridge (CHB) inverters are widely used in megawatt variable speed drives, where the voltage level normally varies from seven to thirteen and the number of active switching devices used in the inverter is in the range of 36 to 72. The design of a simple modulation scheme for such inverters with superior harmonic performance is a challenging task. This project presents a novel digital multilevel modulation (DMM) scheme for multilevel CHB inverters. This scheme is very simple, flexible and easy to implement. To generate gate signals for all the active switches in the inverter, the scheme needs only to calculate a three-phase sine function once followed by a number of subtractions in each sampling period. In this project, the principle of the proposed modulation scheme is elaborated and its harmonic performance is analyzed. Comparisons are carried out between the DMM scheme and carrier based modulation schemes including phase-shifted and level-shifted modulations. It is demonstrated that the harmonic performance of the DMM scheme is on par with the best of carrier based modulation techniques. On the inverter side, line-to-line voltage THD of inverter output for the proposed modulation scheme is as low as IPSD modulation scheme. On the line side, line current THD is as low as phase-shifted modulation scheme because of balanced poser consumption in each power cell. Under the condition of device switching frequency unchanged, a new algorithm is developed to combine the advantages from both phase-shifted and IPD modulation schemes and conquer the drawback of both schemes. The simulation result shows that new modulation scheme has almost same line-to-line voltage harmonic spectrum from light to rated load with balanced power cells.

A novel digital modulation scheme for multilevel cascaded H-bridge inverters in high power AC drives

The multilevel cascaded H-bridge (CHB) inverters are widely used in megawatt variable speed drives, where the voltage level normally varies from seven to thirteen and the number of active switching devices used in the inverter is in the range of 36 to 72. The design of a simple modulation scheme for such inverters with superior harmonic performance is a challenging task. This project presents a novel digital multilevel modulation (DMM) scheme for multilevel CHB inverters. This scheme is very simple, flexible and easy to implement. To generate gate signals for all the active switches in the inverter, the scheme needs only to calculate a three-phase sine function once followed by a number of subtractions in each sampling period. In this project, the principle of the proposed modulation scheme is elaborated and its harmonic performance is analyzed. Comparisons are carried out between the DMM scheme and carrier based modulation schemes including phase-shifted and level-shifted modulations. It is demonstrated that the harmonic performance of the DMM scheme is on par with the best of carrier based modulation techniques. On the inverter side, line-to-line voltage THD of inverter output for the proposed modulation scheme is as low as IPSD modulation scheme. On the line side, line current THD is as low as phase-shifted modulation scheme because of balanced poser consumption in each power cell. Under the condition of device switching frequency unchanged, a new algorithm is developed to combine the advantages from both phase-shifted and IPD modulation schemes and conquer the drawback of both schemes. The simulation result shows that new modulation scheme has almost same line-to-line voltage harmonic spectrum from light to rated load with balanced power cells.