Current measurements in digitally controlled AC drives

Author

Song, Seung-Ho ; Choi, Jong-Woo ; Sul, Seung-Ki

Author_Institution

Sch. of Electr. Eng., Seoul Nat. Univ., South Korea

Volume

6

Issue

4

fYear

2000

Firstpage

51

Lastpage

62

Abstract

In this article, the current-sampling error has been investigated in the field-oriented control of an AC machine by a PWM inverter. The expression of the harmonic current due to a low-pass filter has been studied analytically from the reference voltage vector in the SVPWM strategy. The fundamental components of the current-sampling error causes improper torque regulation while the high-frequency ripple of the error introduces permissible gain of the current regulators with a resultant impairment in dynamic behavior and limited stability range of the control systems. It has been proposed that the magnitude and phase error from the filter can be avoided with delayed sampling. The effectiveness of the delayed sampling was verified through simulations and experimental results including steady state and dynamic responses

Keywords

AC motor drives; PWM invertors; digital control; dynamic response; electric current control; electric current measurement; low-pass filters; machine control; torque control; AC machine; PWM inverter; SVPWM strategy; control systems; current measurements; current regulators; current-sampling error; digitally controlled AC drives; dynamic behavior; dynamic response; field-oriented control; harmonic current; high-frequency ripple; limited stability range; low-pass filter; magnitude; permissible gain; phase error; reference voltage vector; steady state response; torque regulation; AC machines; Current measurement; Digital control; Error correction; Harmonic analysis; Low pass filters; Power harmonic filters; Pulse width modulation inverters; Sampling methods; Voltage;

fLanguage

English

Journal_Title

Industry Applications Magazine, IEEE

Publisher

ieee

ISSN

1077-2618

Type

jour

DOI

10.1109/2943.847916

Filename

847916