1,721,173 research outputs found
Improvement of pulse width modulation techniques
No full textPulse width modulation (P.W.M.) techniques, adopted in inverters for modern variable speed drives, allow an easy adjustment of the fundamental component of the output voltage. Their use, however, entails certain disadvantages such as the complexity of the electronic control circuits and especially the deterioration of the performance of the inversion circuit. There such disadvantages can be reduced by resorting to improved modulation techniques. This paper deals with an advantageous modification of the shape of the modulating wave in the suboscillation P.W.M. techniqu
Convertitori statici per la qualità nell'utilizzazione dell'energia elettrica: introduzione
No full textA new control strategy of the induction motor drives: the direct flux and torque control
No full text
Review of direct torque control methods for voltage source inverter-fed induction motors
No full textThis paper presents a review of recently used direct torque and flux control (DTC) techniques for voltage source inverter-fed induction motors. A variety of techniques, different in concept, are described as follows: switching table (ST) based hysteresis DTC, direct self control (DSC), constant switching frequency DTC with space vector modulation (DTC-SVM). Trends in the DTC-SVM techniques based on neuro fuzzy logic controllers are presented. Some oscillograms that illustrate properties of the presented techniques are show
A simple but high-performace IM speed drive
No full textThe paper deals with an induction motor (IM) speed drive having high performance
over a large speed range in the constant torque region. The drive is built up around an outer loop
of speed equipped with an incremental encoder and two inner loops of torque and flux
implemented in a direct torque control (DTC) scheme. The scheme takes advantage of the
available speed to estimate the motor torque and the stator flux magnitude by means of the IM
current model. This allows the full exploitation of the drive capabilities even in the low speed
range. Furthermore, with a suitable representation of the IM current model, the drive can be
operated down up to zero speed. The paper closes by analytically investigating the detuned
behaviour of the scheme due to a rotor time constant mismatch. Experimental results substantiate
the low-speed capabilities of the scheme and the findings on its detuned behaviour
A simple but high-performance IM speed drive
No full textThe paper deals with an induction motor (IM) speed drive having high performance
over a large speed range in the constant torque region. The drive is built up around an outer loop
of speed equipped with an incremental encoder and two inner loops of torque and flux
implemented in a direct torque control (DTC) scheme. The scheme takes advantage of the
available speed to estimate the motor torque and the stator flux magnitude by means of the IM
current model. This allows the full exploitation of the drive capabilities even in the low speed
range. Furthermore, with a suitable representation of the IM current model, the drive can be
operated down up to zero speed. The paper closes by analytically investigating the detuned
behaviour of the scheme due to a rotor time constant mismatch. Experimental results substantiate
the low-speed capabilities of the scheme and the findings on its detuned behaviour
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