Design and Development of Novel Matrix Converter Performance Enhancement Technique for Induction Motor Drive

Matrix converter is a direct AC-AC converter topology that directly converts energy from an AC source to an AC load without the need of a bulky and limited lifetime energy storage element. Due to the significant advantages offered by matrix converter, such as adjustable power factor, capability of regeneration and high quality sinusoidal input/output waveforms. Matrix converter has been one of the AC–AC topologies that hasreceived extensive research attention for being an alternative to replace traditional AC-DC-AC converters in the variable voltage and variable frequency AC drive applications. In the present paper an indirect space vector modulated matrix converter is proposed. The basic idea of an indirect modulation scheme is to separately apply SVM to the rectification and inversion stages, before combining their switching states to produce the final gating signals. The paper encompasses development of a laboratory prototype of 230V, 250VA three phase to three phase DSP controlled matrix converter fed induction motor drive. The observations and real time testings have been carried out to evaluate and improve the stability of system under various typical abnormal input voltage condition

A New Scheme to Direct Torque Control of Matrix Converter-Fed Five-Phase Permanent Magnet Synchronous Motor

Multiphase machines have gained an increasing attention due to their more advantages in comparison with three-phase machines. In recent literatures, only voltage source inverters (VSIs) have been used to supply five-phase drives. Matrix converters (MCs) pose many advantages over conventional VSIs, such as lack of dc-bulk capacitors, high quality power output waveform and higher number of output voltages. Due to some special applications of multiphase machines such as ship propulsion and aerospace, the volume of these drives is an important challenging problem. As a consequence, using MCs can be a reasonable alternative. In this paper, a new direct torque control (DTC) algorithm using a three-to-five phase MC is proposed for five-phase permanent magnet synchronous motors (PMSMs). All of output voltage space vectors of three-to-five phase MC are extracted and a new switching table is proposed. Because of higher number of output voltages in MCs, there is a degree of freedom to control input power factor to keep close to unit moreover the torque and flux control. In other words, this proposed method use the advantages of both DTC method and MCs. Simulation results show the effectiveness of presented method in different operation modes

Direct Torque Control for Matrix Converter Driven PMSM

This paper carries work on  application of direct torque control for Five-Phase permanent magnet synchronous motor drives. In recent years, only voltage source inverters (VSIs) have been used to supply five-phase drives, but Matrix converters (MCs) pose many advantages over conventional VSIs, such as lack of dc bulk capacitors, high quality power output waveform and higher number of output voltages. Due to some special applications of multiphase machines such as ship propulsion and aerospace, the volume of these drives is an important challenging problem. In this paper, direct torque control (DTC) algorithm using a three-to-five phase Matrix Converter is proposed for five-phase permanent magnet synchronous motors (PMSMs).  Because of higher number of output voltages in MCs, there is a greater degree of freedom to control the torque and flux. In other words, this proposed method use the advantages of both DTC method and MCs. Simulation results show the effectiveness of presented method

Algorithms for Induction Motor Efficiency Determination

Induction motors are the most predominant motors used in the industry. They use two-thirds of the total electrical energy generated in the industrialized countries. Motors fail due to many reasons and many are rewound two or more times during their lifetimes. It is generally assumed that a rewound motor is not as efficient as the original motor. Precise estimation of efficiency of a refurbished motor or any existing motor is crucial in industries for energy savings, auditing and management. Full-load and partial load efficiency can be determined by using the dynamometer procedure which is a highly expensive way and available only in well-equipped laboratories. An inexpensive and easily applied procedure for efficiency estimation is therefore a target of researchers and engineers in the field. In this Ph.D. work, two novel methods for estimating repaired, refurbished, or any existing induction motors’ efficiency are proposed. The two methods (named Method A and Method B) require only a DC test (including temperature measurement), nameplate details, and RMS readings of no-load input power, input voltage, and input current. Experimental and field results of testing a total of 196 induction motors by using Method A are presented and the degree of accuracy is shown by comparing the estimated efficiencies to the measured values. Method B was validated by testing 8 induction motors with acceptable accuracy. To provide the necessary credits to the proposed techniques, an error analysis study is conducted to investigate the level of uncertainty through testing three induction motors, and the results of uncertainty of the direct measurements and no-load measurements using the proposed technique are declared. Derating is a necessary procedure to protect induction motors from overheating which is the main reason of motor failures. The overheating is caused by operating induction motors with unbalanced voltages, over or undervoltage, or harmonics rich power supplies. To derate a machine, its full-load efficiency with balanced undistorted voltages and with unbalanced or distorted voltages must be measured. In many situations in industry and due to critical processes, it is not allowed to interrupt induction machines operation. Hence, an in situ efficiency estimation technique is most required. In this thesis, three novel in situ efficiency estimation algorithms are proposed. The first algorithm is to estimate the full-load and partial loads efficiency of induction motors operating with balanced undistorted voltages. The algorithm is validated by testing 30 induction motors with acceptable accuracy. The second proposed algorithm is for full-load efficiency estimation of induction motors operating with unbalanced voltages. The technique is evaluated by testing 2 induction motors with different levels of voltage unbalance. The results showed an acceptable accuracy. The third proposed algorithm is for full-load efficiency estimation of induction motors operating with distorted unbalanced voltages where the harmonics effect is added. The technique is evaluated by testing 2 induction motors with different levels of voltage unbalance. The results showed an acceptable accuracy. The three novel algorithms are designed by using Genetic Algorithm, pre-tested data, and IEEE Method F1 calculations