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.

Innovative design and feasibility study for a subsea electrical submersible pump system

Abstract: In this paper, a subsea electrical submersible pump (ESP) system with challenging long cabling requirement is designed. Several factors are considered for the design: configuration of the system, length and size of the subsea cable, and load filter parameters for a medium voltage variable frequency drive used in the system. The system requires a 4 km or a 50 km subsea cable connected to the output of the drive. With such long cables, harmonic resonance and motor start-up are two major concerns. Various system designs are investigated through a feasibility study by computer simulation, which includes a steady-state analysis, a frequency response analysis, and a motor starting study. New designs of the load filter for the medium voltage drive are proposed due to unsatisfactory performance of its original standard load filter from the drive manufacturer. The frequency response analysis combined with the steady-state analysis are used to evaluate the effectiveness of new load filters. The motor starting study determines the possibility if the motor can start-up successfully for a system design. The acceptable designs of the system are finalized based on results of the feasibility study.

Induction motor emulation for variable frequency drives testing

Abstract: This paper presents a method employing a simple three-phase transformer connected to a three-phase AC variable load for emulating a standard three phase AC induction motor. Such an emulator could be used for variable frequency drive testing but eliminates any moving parts for higher reliability, reduces audible noise, and eliminates high-cost dynamometers. The method utilizes the concept of assuming that the induction machine is a "rotating transformer." To validate the emulator behavior, a simulation for a line-fed machine and a line fed three-phase transformer with a three-phase variable load is performed. Experimental verification of the inverter-fed machine and transformer are also presented and show excellent emulation capabilities of motor behavior at various slip values.

Passive harmonic filter for power distribution systems

Abstract: A subsea power distribution system includes a three-phase AC power source; multiple variable frequency drives having inputs and outputs, with their inputs connected to the AC power source; an electric motor connected in series to the output of each variable frequency drive; and a passive harmonic filter system having its input connected, in parallel with the variable frequency drives, to the AC power source. The filter system includes multiple harmonic filters, each harmonic filter tuned to a specific harmonic frequency. Each harmonic filter includes a plurality of sub-filters. Each sub-filter includes a reactor connected in series to a main capacitor and one or more detuning capacitors. Each of the multiple harmonic filters is tuned to a different specific harmonic, and includes sub-filters also tuned to the same respective harmonic, and each sub-filter is sized to equally share the kVAR load of its respective harmonic filter.

Energy conservation in automatic fluid flow control using variable frequency drive

Abstract: The Pumping systems account for nearly 20% of the world’s electrical energy demand and range from 25-50% of the energy usage in certain industrial plant operations Pumping systems consume a significant portion of the electricity. Actual energy savings will vary greatly depending on how the discharge pressure of the constant speed pump is controlled and how it is operated after the VFD is installed. In the present work, the flow of pump has been controlled by two different methods, simulation work has been carried out and comparative statement is given. In this paper MATLAB simulink is use to show the performance of energy conservation in automatic fluid flow control using VFD.