Sergiu Ivanov

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The regulation by DTC of the induction motor is a quite " natural " method, being much lighter, as mathematical support, than the vector control, regardless the type of field considered for orientation. Despite its simplicity, the practical implementation of the method rise serious problems, mainly due to the fact that the sampling period for regulation(More)
The power transformers are essential equipment in all transport and distribution grids. Minor faults or defects of this equipment can lead to ravaging effects. The most part of the monitoring and diagnosis systems are developed around expert systems. The expert systems regroup the methods based on analytical models and the ones based on knowledge on the(More)
The paper deals with the vector control and predictive control of the induction motor. For the vector control, the rotor flux oriented one is pointed out, with highlight on the voltage source inverter type. The influence of the most important parameter variations (e.g. stator resistance) is discussed. A simple (and practical) method for avoiding these(More)
The paper applies the diagnosis method based on the analytic model by investigating the output waveforms of the currents, torque and speed specific to a PMSM driving system. Several faults are simulated: open phase, entire phase short circuit in two situations (with and without current measurement, short circuit before and after current sensor respectively)(More)
The paper deals with a technique which uses the predictive concepts in order to obtain the pulse width modulation strategy of a voltage fed inverter. After the technique is briefly described, it is applied for the case when the inverter supplies an induction motor, the reference values of the currents being obtained from a classical vector control scheme.(More)
Depending on user requirements, manufacturing systems dedicated to electrical equipment must produce a wide range of products. The transition from the manufacturing an assortment of product to another involves additional costs which are necessary to adjust the manufacturing system state to the new technology. The manufacturing optimization requires the(More)
In heavy duty drives in the range of hundreds kW, like cement and minerals industries, wound rotor induction motors are used. Important users make use of hundred of such drives, summing hundreds of MW. This type of motors have technical capabilities to easily operate at variable speed. Despite this simple capability, the large amount of losses which occur(More)
The controlled switching can be applied to any type of commutations. Now there are dedicated controllers which are used more often for the switching of the transport and distribution lines, of the small inductive loads, of the capacitors batteries, or the energizing the no load power transformers. The paper presents a microcontroller (8051 family) based(More)
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