Title :
A three-phase current-source type PWM rectifier with feed-forward compensation of input displacement factor
Author :
Zargari, Navid R. ; Joos, Geza
Author_Institution :
Dept. of Electr. & Comput. Eng., Concordia Univ., Montreal, Que., Canada
Abstract :
Three-phase current-source type PWM rectifiers are often used as the front-end power converter unit in utility-interfaced systems. Due to the input filter (needed for current harmonic suppression), the input displacement factor is less than unity. It varies with the rectifier operating point and may result in unacceptable low values. In this paper, a new control method is proposed to achieve unity displacement factor independent of the load conditions. The proposed method controls the phase shift of the input currents in a feedforward fashion. The modulating signals are phase shifted according to the rectifier operating point to always result in near unity input displacement factor. The compensation scheme makes use of a DC current loop and the standard DC voltage regulation loop to produce the modulating signals with the required phase shift. As a result, the control circuitry does not require additional sensors. The PWM pattern is generated online, which results in fast response to transients. The rectifier is analyzed and design equations are derived. A design example is given and theoretical considerations are verified through simulation and by experimental results obtained on a 1 kVA laboratory prototype
Keywords :
compensation; electric current control; load (electric); phase control; phase shifters; power convertors; power factor correction; power system harmonics; pulse width modulation; rectifiers; rectifying circuits; transient response; voltage control; 1 kVA; DC current loop; DC voltage regulation loop; analysis; current harmonic suppression; current-source PWM rectifier; design; feedforward compensation; input displacement factor; input filter; load; phase shift; power converter; power factor; rectifier operating point; simulation; three-phase; transient response; Circuits; Displacement control; Feedforward systems; Harmonics suppression; Phase modulation; Power harmonic filters; Pulse width modulation; Pulse width modulation converters; Rectifiers; Voltage control;
Conference_Titel :
Power Electronics Specialists Conference, PESC '94 Record., 25th Annual IEEE
Conference_Location :
Taipei
Print_ISBN :
0-7803-1859-5
DOI :
10.1109/PESC.1994.349708