Increasing the dynamic torque per ampere capability of induction machines

Abstract

Abstract-The objective of this paper is to present a novel means of increasing the dynamic torque per ampere capability of induction machines. The method developed is based on use of an indirect field oriented controller (IFOC) for the induction machine. It is well known that IFOC allows the rotor flux amplitude to be controlled by the d-axis component of stator current. It is also well established that the flux-producing component of the stator current may be controlled independent of the torque-producing component of the stator current. The principal constraint, however, is that the amplitude of the peak current (the vector amplitude) is limited by the power electronic switch ratings. This constraint implies that optimal partitioning of the current components should be possible. Previously used methods have optimized steady state efficiency or steady state torque per ampere. This paper identifies a dynamic method which achieves transient torques over 35% greater than the prior methods. The limitations of the method and its sensitivity to detuning is also examined.

High-performance motion control of an induction motor with magnetic saturation

“…Previous work in the area of flux selection includes [18], [23], and [25]. The work [18] addresses the problem of torque maximization.…”

“…Specifically, at higher speeds, the optimal flux reference results in significantly larger (in magnitude) torques than when using the standard flux reference. In [23], a method of generating large transient torques was presented. The procedure involves putting the available current into the direct axis to build up the rotor flux and then rapidly switching the available current from the direct axis to the quadrature axis to produce a large torque.…”

Maximum Torque per Ampere Operation of Brushless Doubly Fed Induction Machines

“…At low speeds, this optimization generally requires operating the machine at maximum torque per ampere to achieve high torque output for fast acceleration of the connected load [5]. A maximum torque per Ampere scheme was proposed by [6] to minimize the stator current and converter rating in certain speeds.…”

“…A maximum torque per Ampere scheme was proposed by [6] to minimize the stator current and converter rating in certain speeds. Other works are done for maximum torque per ampere capability of IPMSMs [7] and induction motor drives [5], [6].…”

The Field Orientation Principle in Control of Induction Motors

“…closed-loop,[179][180][181][182][207][208] Phasor diagram of stator currents, 2 Position control,189-190, 218-223 linear feedback, 190-191, 218-220 Vectors, see Space vectors Vector control systems, 159·223 withairgap iluxorientation, 168·174, 199·201 direct, 170·171,200·201 indirect, 171·173, 199·201 with current source inverters, 175· 176, 202·205 with rotor flux orientation, 98·123 direct, 100·105, 117·118 indirect, 106·108, 118·123 with stator flux orientation, 160.168, 197·201 direct, 164·166, 200·201 indirect, 166·168, 197·203 with universal field orientation, 173 Voltage control in scalar speed control systems, 51, 255 52 in voltage source inverters, 130·138 Voltage equation in excitation reference frame, 29 in stator reference frame for T equivalent circuit, 13·15 for r equivalent circuit, 46 for I" equivalent circuit, 55 steady.state, 25 for T equivalent circuit, 25 for r equivalent circuit, 46 for I" equivalent circuit, 56…”