Multiphase induction motor drives - a technology status review

The area of multiphase variable-speed motor drives in general and multiphase induction motor drives in particular has experienced a substantial growth since the beginning of this century. Research has been conducted worldwide and numerous interesting developments have been reported in the literature. An attempt is made to provide a detailed overview of the current state-of-the-art in this area. The elaborated aspects include advantages of multiphase induction machines, modelling of multiphase induction machines, basic vector control and direct torque control schemes and PWM control of multiphase voltage source inverters. The authors also provide a detailed survey of the control strategies for five-phase and asymmetrical six-phase induction motor drives, as well as an overview of the approaches to the design of fault tolerant strategies for post-fault drive operation, and a discussion of multiphase multi-motor drives with single inverter supply. Experimental results, collected from various multiphase induction motor drive laboratory rigs, are also included to facilitate the understanding of the drive operatio

Study of the generator/motor operation of induction machines in a high frequency link space power system

Static power conversion systems have traditionally utilized dc current or voltage source links for converting power from one ac or dc form to another since it readily achieves the temporary energy storage required to decouple the input from the output. Such links, however, result in bulky dc capacitors and/or inductors and lead to relatively high losses in the converters due to stresses on the semiconductor switches. The feasibility of utilizing a high frequency sinusoidal voltage link to accomplish the energy storage and decoupling function is examined. In particular, a type of resonant six pulse bridge interface converter is proposed which utilizes zero voltage switching principles to minimize switching losses and uses an easy to implement technique for pulse density modulation to control the amplitude, frequency, and the waveshape of the synthesized low frequency voltage or current. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straight forward. The feasibility of the proposed power circuit and control technique for both active and passive loads are verified by means of simulation and experiment

Multilevel Converters: An Enabling Technology for High-Power Applications

| Multilevel converters are considered today as the state-of-the-art power-conversion systems for high-power and power-quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in-depth and self-contained information, while recent advances and state-of-the-art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.Ministerio de Ciencia y Tecnología DPI2001-3089Ministerio de Eduación y Ciencia d TEC2006-0386

Optimal Modeled Six-Phase Space Vector Pulse Width Modulation Method for Stator Voltage Harmonic Suppression

Dual Y shift 30 six-phase motors are expected to be extensively applied in high-power yet energy-effective fields, and a harmonic-suppressing control strategy plays a vital role in extending their prominent features of low losses and ultra-quiet operation. Aiming at the suppression of harmonic voltages, this paper proposes a six-phase space vector pulse width modulation method based on an optimization model, namely OM-SVPWM. First, four adjacent large vectors are employed in each of 12 sectors on a fundamental sub-plane. Second, the optimization model is constructed to intelligently determine activation durations of the four vectors, where its objective function aims to minimize the synthesis result on a harmonic sub-plane, and its constraint condition is that the synthesis result on the fundamental sub-plane satisfies a reference vector. Finally, to meet the real-time requirement, optimum solutions are obtained by using general central path following algorithm (GCPFA). Simulation and experiment results prove that, the OM-SVPWM performs around 37% better than a state-of-the-art competitive SVPWM in terms of harmonics suppression, which promise the proposed OM-SVPWM conforms to the energy-effective direction in actual engineering applications.Peer reviewe

Modeling and Control of a 7-phase Claw-pole Starter-alternator for a Micro-hybrid Automotive Application

This paper deals with the modeling and the control of a new high power 12V Integrated Starter Alternator (ISA). This system is used to bring micro-hybrid functions to standard Internal Combustion Engine (ICE) vehicles. The drive is composed of a seven-phase synchronous claw-pole machine with separate excitation, supplied with a seven-leg Voltage Source Inverter (VSI) designed for low voltage and high current. The system is modeled in a generalized Concordia frame and a graphical description is used to highlight energetic properties of such a complex system. A control scheme is then deduced from this graphical description. Two controls are achieved in generator mode and compared: one is using the VSI in a square-wave mode, the other in a Pulse Width Modulation (PWM) mode. Experimental results are provided.This work was supported by the French car supplier Valeoand the regional council of France Region-Nord-Pas-De-Calais

The monitoring of induction motor starting transients with a view to early fault detection.

The aim of this work is to investigate the possibility of detecting faults in a 3 phase Induction motor by monitoring and analysing the transient line current waveform during the starting period. This is a particularly onerous time for the machine and the inter-relationships between parameters such as current, torque, speed and time are very complex. As a result two parallel paths of investigation have been followed, by methods of experimentation and computer simulation. Transient line current signals have been obtained from purpose built test rigs and these signals have been analysed in both the time and frequency domains. In order to assist with the comprehension of this data a sophisticated computer simulation of the induction motor during the starting period has also been developed. Computer simulation of the induction motor has been developed initially using the two and then three phase induction motor voltage equations which are solved by numerical integration. Using these techniques it has been possible to detect small degrees of fault level for both wound and cage rotor machines by analysing the line current waveform during the starting period. Good agreement has been found between the real and simulated data. A range of Digital Signal Processing techniques have been utilised to extract the components indicative of rotor faults. These techniques were at first wideband and highly numerically intensive, some originating from Speech Processing. The final processing techniques were far simpler and selected by analysis of the results from experimental data, both real and simulated

SINGLE PHASE TO THREE PHASE CONVERTER FOR VARIABLE SPEED DRIVE APPLICATIONS

This final report is mainly to give an overview about the “Single phase to Three phase converter for variable speed drive applications” project and also the progress of the project. Due to unavailability and high cost installation of three phase power network, power inverter is very important to address this problem. Here comes the purpose of the project to develop electronic converters that applicable for three phase equipment that equipped with variable speed drive (VSD) applications to operate in single phase supply. This project proposed two converter topologies for circuit modelling and simulation. There are PRC and PWM method. The modeling for the project will be done using PSPICE software. The model will be simulating based on the load requirement which is 3-phase motor for the converter design. Based on the simulation analysis it has been proved that these two methods can be implemented in order to achieve the project’s objective which to produce 3 phase power from single phase supply with improved performance and better efficiency. For this given time frame the project only focus on the methodology on how to develop the converter using proposed method but without control strategy. Further improvement or works can be carried out to improve the design by implemented control strategy for the converter

MATLAB Simulation Model to Improve Voltage Sag Due to Starting of Induction Motor Using STATCOM

In industrial sector or process continuity plant the continuity of the industrial processes becomes a more important factor for the organisation profit and economical balance. But sometime its get interrupted due to electrical faults, low voltage supply, voltage sag some mechanical faults or man made mistakes. Out of it voltage sag is one of the most persisting factors to be taken in to account, starting high power loads like induction motors or heavy loads draws a very large amount of current then the system rated specified voltages. So these sags gets detected by the under voltage relays or over current relays and consequently act in opening up of the breaker and hence brings distortion in the process continuity of the plants working processes. And further the cost of restarting the process again and delay in the order supply acts more to the damage done. So, it’s really necessary to compensate for the reactive power or the voltage sag occurred during this time. So one of the available alternative is the modern generation FACT controller like STATCOM which is a shunt operated reactive power compensating device or reactive power exchanging device for improving the voltage system profile of the system, so here in this thesis report we will try to investigate the operation of the STATCOM. Its device characteristics, its constructional details and take a special model in the MATLAB simulation to how the compensating ability of the STATCOM and its benefits and con will be figured out. Here we will also find out some of the other ways to improve the voltage sag improvement and theirs features. Little focus will be also on the reactive power analysis, how it affects the system and its necessity will be discussed in brief. Little light will also be given to the FACTS class of the device its modern trends and its benefits to the electrical engineering sector. Here in the STATCOM circuit which comes across the FACT device class will be using a voltage source PWM operated inverter circuits for its operation. The facts technology is mainly based upon implementing power electronics technology in the field of power system dynamics for its stability and improvement of the various important contributing part of the ower system like reactive power compensation, improvement of the stability of the system