Topic
Variable-frequency drive
About: Variable-frequency drive is a research topic. Over the lifetime, 837 publications have been published within this topic receiving 5691 citations. The topic is also known as: VFD.
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TL;DR: A new speed prediction method of variable frequency drive induction motor based on second-order increment that realizes the prediction and control of the motor speed, the effect of reducing the amount of calculation is obtained under the condition of small disturbance error, and the accuracy of speed prediction is improved.
Abstract: The current use of first-order incremental prediction is simply the use of motor speed increment to predict the next moment motor speed. For the problem that the prediction error is large when the ...
1 citations
01 Jan 2020
TL;DR: The proposed MFTC based PWM technique shows better performance in spreading the motor acoustic noise spectrum as compared to the CFTC based SVPWM technique, in which the carrier frequency is modulated accordingly.
Abstract: To spread the motor acoustic noise, various PWM techniques have been proposed for Voltage Source Inverter (VSI) fed Induction Motor Drives. Random PWM techniques are the most useful techniques to reduce motor acoustic noise. It is difficult for real-time implementation, unpredictable switching losses and the motor suffers from shaft torque dynamics due to adventitious excitation of natural frequencies. The Constant Frequency Triangular Carrier (CFTC) based Space Vector PWM technique will inject switching frequency harmonics into the Variable Frequency Drive, where the harmonics are concentrated at integral multiples of switching frequency which generate audible acoustic noise. To spread the audible harmonic spectrum, this paper presents a Modulated Frequency Triangular Carrier (MFTC) based SVPWM technique, in which the carrier frequency is modulated accordingly. Both the CFTC and the proposed MFTC based PWM techniques are simulated using MATLAB/Simulink. The experiments are conducted on a low-cost TMS320F28379D controller. The proposed MFTC based PWM technique shows better performance in spreading the motor acoustic noise spectrum as compared to the CFTC based SVPWM technique.
1 citations
Patent•
18 Aug 2020
TL;DR: In this paper, a mechanical unloader such as a slide valve is used to reduce the internal volume ratio of the compressor and allow a more efficient speed to be maintained by a variable frequency drive (VFD) while reducing the compressor capacity based on the load.
Abstract: Control systems and methods for increasing efficiency of a compressor while the compressor capacity exceeds compressor load, by using a mechanical unloader such as a slide valve to reduce the internal volume ratio of the compressor and allow a more efficient speed to be maintained by a variable frequency drive (VFD) while reducing the compressor capacity based on the load. Control systems include the VFD, a controller for the VFD and the mechanical unloader, and temperature sensors. Compressor embodiments further include one or more compressors and mechanical unloaders operated by the control systems.
1 citations
TL;DR: In this article, a case study was conducted to evaluate power converters for shipboard applications and to recommend converters that meet lower harmonic distortion levels and torque ripples in electric propulsion motors.
Abstract: Electric propulsion motors are operated from a variable frequency drive, which supplies power to motors at a frequency appropriate to the desired speed. The objective of this study was to evaluate power converters for shipboard applications and to recommend converters that meet lower harmonic distortion levels and torque ripples. Two systems were studied in detail : Cyclo-converters and PWM-converters. Cyclo-converters are the obvious choice where size, weight and efficiency are the most critical issues. However they have a disadvantage in power factor and they produce severe torque ripples in the motor which makes them unacceptable without special systems. PWM-converters produces better motor current waveform and eliminates common mode voltage issues at the motor, but suffers a multiple stages of power conversion and the isolating transformer. Results of this case study show that PWM-converters are more advanced and efficient drives for induction motor of electric propulsion ship.
1 citations
TL;DR: The main aim of the project is to control the speed of a three-phase induction motor with energy-saving with the aim of providing a basic understanding of Variable Frequency Drive (VFD) terms.
Abstract: This paper is about the various applications of Variable frequency drive (VFD) on a three-phase induction motor. In this, we carry out different on load and no-load test on a three-phase induction motor. Variable Frequency Drive (VFD) is an electronic device that is used to change utility power source to variable frequency. Variable Frequency Drive (VFD) can be used to control the speed of a three-phase induction motor. A load of an Induction Motor is not constant it varies according to the load requirement. So, speed must be changed as per increasing or decreasing the load. The main aim of the project is to control the speed of a three-phase induction motor with energy-saving. Hence to maintain the speed supply voltage and frequency must be varied accordingly. There are several ways to define Variable Frequency Drive (VFD). This paper is intended to provide a basic understanding of Variable Frequency Drive (VFD) terms, Variable Frequency Drive (VFD) Operation.
1 citations