Performance Improvement of Grid-Connected Induction Motors through an Auxiliary Winding Set

Abstract

A technique to improve the performance of grid-connected induction motors by exploiting an auxiliary winding set is proposed in this paper. This auxiliary winding features the same distribution of the main winding, although with a reduced number of turns and it is fed by an inverter a fraction of the power in comparison with the rated size of the induction motor. As shown in the paper, through the auxiliary winding, it is possible to set the machine power factor, increasing the efficiency of the power conversion system and mitigating speed oscillations due to torque disturbances. A mitigation of the grid current peaks due to motor start-up is obtainable. First, the proposed technique is theoretically introduced, then a feasibility assessment is accomplished by simulations.

High-Efficiency and High-Performance Power Electronics for Power Grids and Electrical Drives

“…This Special Issue includes ten contributions on various techniques aimed at improving the efficiency and performance in power electronics applications for power grids and electrical drives [1][2][3][4][5][6][7][8][9][10]. Such articles were authored by international research teams from several countries and covered different topics.…”

“…(a) Power converters used to interface RESs and ESSs with microgrids [1,3,5,7,8,10] or to recharge ESSs in electric vehicles [9]; (b) Performance increase in VSDs and direct online induction motors [4,6]; (c) Application of electrical loss minimization techniques to microgrids based on RESs [2].…”

“…In [6], Tornello et al presented a technique to improve the performance of induction motors by exploiting an auxiliary winding set supplied by a partial power inverter. In fact, three-phase DOL-IMs are the most dominant solution in the industrial sector, providing a variety of constant speed and variable load applications where dynamic requirements are not critical.…”

“…In such applications, the additional cost implied by a VSD with a full-size inverter is not justified. However, the authors of [6] showed that it is possible to compromise cost and performance by using an auxiliary winding and a partial power inverter. The auxiliary winding features fewer turns than the main one and thus has lower voltage and power ratings.…”

Internal capacitive compensation of the reactive power of the screw electromechanical converter

“…However, they are still burdened by low power factor at partial loads, which can only be mitigated by adding power factor correction capacitors. In [17], in contrast to variable-speed drives, which have torque or speed control and use pulse-width modulation strategies [5][6][7], it is proposed to overcome the typical disadvantages of conventional induction motors, mainly low efficiency and power factor, by using less expensive partial power converter. According to the approach [17], a special induction machine is used, which includes a main winding connected to the network and an auxiliary three-phase winding with a smaller number of turns, located in the same slots of the stator as the main one.…”