C.R. da Silva

Vector and scalar modulation for six-phase voltage source inverters

This paper presents an improved PWM control of six-phase voltage source inverters supplying a split-phase induction motors. The approach is based on a space vector modulation and designed to improve the performance of the system in terms of THD and DC bus utilization. Several scalar and vectorial patterns are proposed and evaluated by using the total harmonic distortion as a figure of merit. Simulation and experimental results are presented to demonstrate the feasibility of the proposed solutions.

Six-phase AC drive system with reduced common-mode voltage

This paper investigates a six-phase machine drive configuration that permits to reduce the common-mode voltage. The drive system consists of a six-phase inverter feeding a six-phase induction motor, which is adequate to develop a high power system with current rating restrictions. Several pulsewidth modulation techniques for generating gate signals to command the power switches of the six-phase inverter are presented. The proposed strategies permits to reduce either the mean value or the instantaneous value of the common-mode voltage. Simulation and experimental results demonstrates the feasibility of the proposed solution.

Independent voltage control for series connected six-phase and three-phase induction machines

A lot of relevant concepts related to series connection and independent control of multiphase machines supplied from a single current-controlled voltage source inverter have been recently demonstrated by some researchers. These previous evaluation give a great contribution to further improvements of multimachine series connected applications. Following the initial proposition, which includes an evaluation based on the general theory of electrical machines, this paper evaluates PWM schemes for two-motor series connected motor drive. The goal of this paper is to show how to achieve independent voltage control and to evaluate the switched voltage profile in the motors windings. Scalar and vector approach are addressed and, simulation and experimental results are shown to illustrate details discussed in the paper.

Effect of winding harmonics on the asynchronous torque of a single-phase line-start permanent-magnet motor

This paper presents an analytical method for calculating the effect of winding harmonics on the asynchronous torque of a single-phase line-start permanent-magnet motor. The method is an extension of earlier work, which combines symmetrical-component analysis with dq-axis theory to model the various components of forward and backward rotating fields. The effect of individual winding harmonics is brought out both theoretically and experimentally, by comparing calculated and measured torque/speed characteristics for a series of six motors with different distributions of turns in both the main and auxiliary windings.

A model of double star induction motors under rotor bar defect for diagnosis purpose

This paper investigates the modelling of a double star induction motor when this one operates under rotor fault. A special attention is paid only to the rotor defect. The use of double star induction motors or six-phase induction motors is increasing and we can find it in high power process. Its main advantage lies in most reliability in case of a normal operating system. In order to monitor a huge power process, we have to focus our attention on signals given the state of health of an electromechanical axis in the whole. Consequently, an appropriated model is proposed allowing the quantification of the severity of the fault when rotor bars are defected. This is made thanks to the most widespread approach: the spectral analysis of the stator current using the well know method named motor current signature analysis (MCSA)

Reversible six-phase AC motor drive systems with reduced switch count

This work presents four reduced switch count six-phase AC motor drives. The configurations were conceived to operate without the use of the boost inductor filter. The drive systems provide both bidirectional power flow and power factor control. The work presents the operating principles and control strategies of the topologies. Experimental and simulation results are presented.

On-line estimation of the stator resistance of a six-phase induction machine

This paper proposes a technique to determine on-line the stator resistance of a six-phase induction machine in a six-phase drive system. Besides the stator resistance, the stator leakage inductance can be also estimated. These parameters are obtained by solving a least squares minimization problem. The technique is conceived to be used online with the drive strategy without disturbing machine electromagnetic torque. Experimental results are used to demonstrate the feasibility of the proposed technique.

A New Approach for Inter-Turn Short-Circuit Detection in Six-Phase Induction Motor

Induction machine is very important for a lot of industry applications. Certainly the importance of induction machine by itself justify several research works on fault detection. Most of research works deal with three-phase induction machines. This work gives attention to stator fault detection in double winding three-phase machine, which can be seen as a six-phase induction machine. As a result it is shown how to exploit the six-phase model approach to detect fault as well as to better understand the physical behavior of the short-circuits in double winding induction machines. Experimental results coming from doubles star induction machines prototype systems confirm the good behavior of adopted modelling

Common-mode voltage reduction in a reduced-switch induction motor drive system

This paper proposes a reduced switch count inverter with common-mode voltage mitigation capability. The drive system consists of a four-leg inverter feeding a dual-winding induction motor. Pulse-width modulation techniques for generating the command signals for the power switches of the inverters are presented. The proposed strategies permit to reduce or even eliminate the common-mode voltage. Comparison with others strategies are performed in order to establish their advantage and disadvantage. Simulation and experimental results are presented to demonstrate the feasibility of the proposed solution.

Reduced switch count dual-winding ac drive system with common-mode voltage mitigation

This paper proposes reduced switch count inverter solutions to mitigate the common-mode voltage. The drive system consists of a five-leg converter feeding a dual-winding induction motor. The pulse-width modulation techniques for generating the command signals for the power switches of the converters are presented. The proposed strategies permit to eliminate the common-mode voltage. Simulated and experimental results are presented to demonstrate the feasibility of the proposed solution