Improvement of Immunity of Adjustable AC Drives with Induction Motors on Voltage Sags

In this paper, symmetrical and unsymmetrical voltage sags are classified according to the severity of the effects produced on the behavior of induction motors, using the double-cage rotor model. The analyzed variables are: current and torque peaks, and speed loss in transient and steady states. The severity of these effects is analyzed with 14640 voltage sags, both at the beginning of the voltage sag and when the voltage is recovered, by changing the type, magnitude, duration, and initial-point-of-wave. Four mechanical torque loads were used for the analysis, three with constant behavior and one with quadratic behavior. The results show the durations and initial-point-of-wave with more severe effects for each type of voltage sag. Finally, a classification that depends on the type of voltage sag and the variable of interest is obtained.

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Sensitivity of Induction Motor under Symmetrical Voltage Sags and Interruption

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.875-877.1923 ◽

2014 ◽

Vol 875-877 ◽

pp. 1923-1928 ◽

Cited By ~ 1

Author(s):

Surya Hardi ◽

Ismail Daut ◽

Ismail Rohana ◽

Muhd Hafizi

Keyword(s):

Power Systems ◽

Distribution Systems ◽

Single Phase ◽

Induction Motors ◽

Short Circuit ◽

Inrush Current ◽

Voltage Sags ◽

Three Phase ◽

Nominal Voltage ◽

Transmission And Distribution

Voltage sags and interruption are one of most important of power quality problems. They can influence performance of equipment such as induction motors. They are generally caused by short circuit faults in transmission and distribution systems which propagate in entire of power systems. When their appear at a motor terminal, its effects are the speed and the torque will decrease to a level lower than values of the normal and even the motor become stall if magnitude of the voltage sags and duration exceed certain limit. The voltage can return to nominal voltage after end of the voltage sag and interruption. The motor will experience re-acceleration to normal condition is accompanied by large inrush current. A study on induction motors was carried out to confirm these effects. Single-phase and three-phase of small induction motors were used for investigating the effects caused by symmetrical voltage sags and interruption through experimental and simulation.

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Dual 3-Phase Bridge Multilevel Inverters for AC Drives with Voltage Sag Ride-through Capability

Energies ◽

10.3390/en12122324 ◽

2019 ◽

Vol 12 (12) ◽

pp. 2324

Author(s):

Vitor Fernão Pires ◽

Joaquim Monteiro ◽

José Fernando Silva

Keyword(s):

Control System ◽

Supply Voltage ◽

Voltage Sag ◽

Voltage Sags ◽

Power Supply Voltage ◽

Multilevel Converters ◽

Variable Speed Drives ◽

Ac Drives ◽

Ac Motor ◽

Drive And Control

One of the main power quality issues that can affect variable speed drives (VSDs) is the occurrence of voltage sags on their AC power supply. Voltage sags can affect the inverter nominal operation, leading to a malfunction of the AC motor. This paper presents an inverter with resilient capability to voltage sags. The topology consists of two conventional three-phase bridge inverters arranged to require just a single DC source. This inverter is also characterized by a voltage multilevel operation, providing the full advantages of multilevel converters without the need for level balancing. Associated with this AC motor driver, a control system based on a field-oriented controller with a vector voltage modulator that will enable voltage sag ride-through capability is proposed. The proposed control system does not require any changes in the occurrence of voltage sags. To verify the characteristics of the proposed drive and control system, simulation tests are provided. Simulation results confirm the voltage sag resilient capability of the proposed multilevel converter.

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