Variable Speed Drive DC-Bus Voltage Dip Proofing

This paper proposes a power electronic module that uses a switched capacitor for retaining the integrity of the dc-link voltage of a variable speed drive (VSD) during a 0.2 s short-term power interruption (STPI). Ride-through was achieved through switched capacitor onto the dc bus. However, this technique presents a challenge of the high inrush currents during a ride through compensation. In this work both analytical and experimental investigations were conducted in order to reduce the in-rush currents and its impact on the performance of the VSD during the STPI. Inrush peak currents were reduced by approximately 90%. Experimental results showed torque pulsations of 12.8% and 14.3% at the start and end of dc-link voltage compensation, respectively. A method for sizing the switched capacitor and the inrush limiting resistors is proposed. This methodology is based on the use of readily available nameplate information of the VSD and the electric motor. The proposed module can be retrofitted to existing VSDs that are based on v/f control.

Implementation and Control of Six-Phase Induction Motor Driven by a Three-Phase Supply

This paper is interested in implementing and controlling a modified six-phase induction motor (MSPIM) when fed from a three-phase supply either via an inverter or with a direct grid connection loaded by a centrifugal pump. The main aims of using the MSPIM are to enhance motor reliability and reduce torque pulsation. A three-to-six phase transformer has been designed, implemented, and employed to enable the SPIM to be driven from a three-phase supply. It is preferable to use the three-to-six phase transformers integrated with three-phase inverter on using the six-phase inverter to generate lower values of harmonics and lower steady-state error of speed and reduce the starting current and because also it isolates the primary circuit from the secondary, and the cost will be lower compared to the design of a special six-phase inverter. Dynamic models of SPIM, three-to-six phase transformer, and three-phase variable speed drive are derived. Then, a scalar (V/F) closed-loop control of SPIM is employed, and the results are discussed. Fine-tuning of PID controllers is used to keep the motor speed tracking the reference value. A low pass filter is connected to reduce the ripple of voltage and current waveforms. An experimental setup has been built and implemented to check the possibility of controlling SPIM by a variable speed drive system fed from a three-to-six phase transformer. It is found that the proposed method can be effectively used to drive the SPIM from a three-phase supply.

Electric Motors for Variable-Speed Drive of Lock Valves

Improving the operational reliability of nuclear power plants, combined heat and power plants (CHP), as well as oil and gas pipelines is a priority task in the development of a variable-speed drive for lock valves used at these facilities. This paper analyzes the technical requirements for such devices: the motor has been selected, its electrical equilibrium and moment equations have been obtained; recommendations for the selection of the kinematic drive scheme have been formulated. Based on the theoretical data obtained, a prototype has been developed, manufactured, and tested.

Performance of Frequency Regulation on Power in the Development of Variable Speed Drive Training Kit as a Learning Media for Motor Control Practices

This study develops a variable speed drive training kit for electric motor control practice media in vocational education. This is research and development with the ADDIE model. The stages of the ADDIE model carried out are Analyze, Design, Development, Implementation, and Evaluation. A Variable Speed Drive (VSD) system consists of two panels, 1) a Variable Speed Drive panel and 2) a control and metering panel. The VSD Training kit module unit using Altivar 71 is a learning medium about electric motor control systems. The VSD Training kit can work well based on trials. The test results of the training kit variable speed drive function test show that at a frequency of 20 Hz, the magnitude of the current in the R, S, and T phases get the lowest value.

Analysis Of The Effect Of Frequency Decrease On Performance On Five Phase Induction Motor

Almost 70% of the energy produced by the generator is consumed by electric motors. The use of induction motors in industry and factories is more profitable than DC or synchronous motors, one of the advantages is easy maintenance and high efficiency. On machines in the industry speed regulation is absolutely necessary. Along with the development of power electronics, this has become very easy to do, namely by supplying a motor with a variable speed drive (VSD) inverter. With the supply of a variable speed drive inverter, it is possible to adjust the motor speed by adjusting the voltage frequency.This study was conducted to determine the effect of decreasing the frequency using a variable speed drive inverter on the performance of a five-phase induction motor. Tests are carried out at a frequency of 50 Hz (grid frequency), 35, 40, 45, 50 Hz (inverter frequency) and the motor is loaded at 0.5, 1, 1.5, 2, 2.5Nm. From the research, it was concluded that, among others, the use of a variable speed drive inverter resulted in greater motor losses and the motor produced a louder sound. At the same frequency (50 Hz) the efficiency of the motor is better when supplied directly from the grid.

Electric Motors for Variable-Speed Drive of Lock Valves

Improving the operational reliability of nuclear power plants, combined heat and power plants (CHP), as well as oil and gas pipelines is a priority task in the development of a variable-speed drive for lock valves used at these facilities. The paper analyzes technical requirements for such devices; the motor has been selected, its electrical equilibrium and moment equations have been obtained; recommendations for the selection of the kinematic drive scheme have been formulated. Based on the theoretical data obtained, a prototype has been developed, manufactured and tested.