Dynamic analysis of current regulators for AC motors using complex vectors

Abstract

Abstract-The analysis and design of current regulators for polyphase ac loads is presented using complex vector notation. The ac motor current regulation problem is analyzed by studying both the command tracking and disturbance rejection capability of the current regulator. The use of complex vector notation and the generalization of classical control tools like root locus, frequency-response functions, and dynamic stiffness functions to complex vectors provide a way of comparing the performance of different controller topologies. Limitations in the performance of the synchronous frame proportional and integral current regulator are outlined, and several ways of improving its performance are suggested and investigated.Index Terms-AC current regulators, complex vector analysis, complex vector controls design.

AC Current Controller with Error-Free Feedback Acquisition System

“…Analysis and design of current controllers are simplified by introducing complex vectors [5], [6], [10], where the stator current in stationary frame is represented by i s = i αs + ji βs , while the current in the synchronous d-q frame is i e = i d + ji q . Modeling should include the computation delays, as well as modulation delays and feedback acquisition delays [1], [12].…”

Digital current control in a rotating reference frame - Part I: System modeling and the discrete time-domain current controller with improved decoupling capabilities

“…(1), an additional complex-valued summand appears in the linear differential equation. This term is referred to as a frame speed dependent cross-coupling term [21] since a coupling of the direct transfer dynamics (i.e. dto-d-component and qto q-component) with the respective orthogonal (indirect) transfer dynamics (i.e.…”

“…These modern control platforms allow high (over-) sampling rates, high computational power and an enormous amount of variable storage capacity. Therefore, the results in [19], [20] and [21], which are based on continuous time-domain analysis, are transferred to the discrete timedomain in [22] giving rise to the discrete nature of modern DSP-based power converter systems. Further, recent publications, e.g.…”

State-space flux-linkage control of bearingless synchronous reluctance motors

“…then (11) equals (12). It is worth mentioning that the IMC principle is not the only possible approach for the controller design.…”

“…It is worth mentioning that the IMC principle is not the only possible approach for the controller design. Other approaches, such as the complex vector design for PM machines [12], [13], could be applied as well. Furthermore, by changing (12), different closed-loop dynamics could be easily selected.…”