DSP-based space-vector PWM pattern generators for three-phase current source rectifiers and inverters

Abstract

Current source converters (rectifiers and inverters) are usually modulated using off-line pattern generators, due to the complex requirements of the switch gating signals. However, on-line patterns (carrier-and space-vector-based) offer a number of control advantages, such as tracking-error minimization, zero steady-state error, and potential implementation of enhanced control strategies. With the capability of microprocessors and digital signal processors (DSPs), digital space-vector modulation offers an interesting alternative to standard carrier-based modulation techniques. This paper addresses practical issues such as switching-frequency minimization, uncharacteristic-harmonic reduction, and delay compensation. Improved space-vector algorithms are derived that (a) reduce switching frequency, (b) improve reference tracking, and (c) reduce harmonic distortion. Experimental results on a 2-kVA current source rectifier are used to validate the proposed algorithms and control techniques. On module g6n£ralement les convertisseurs de sources de courant (rectificateurs et inverseurs) en utilisant des g£n£rateurs hors-ligne, a cause des exigences complexes des signaux de commande. Cependant, la generation en ligne offre plusieurs avantages comme la minimisation de l'erreur de poursuite, une erreur nulle en regime permanent, et 1'implantation potentielle de meilleures strategies de commande. Les microprocesseurs et les processeurs numlriquesde signaux (DSP) offrent une alternative intlressante aux modulations de porteuse standards. Cet article traite de sujets pratiques tels que la minimisation de la frequence de commutation, la reduction d'harmonique non-caractlristique, et la compensation de d£lai. On derive des algorithmes a espace vectoriel amlliores qui r€duisent la frequence de commutation, amlliorent la poursuite de la reference, et r£duisent la distortion harmonique. Des resultats expe>imentaux sur un rectificateur de source de courant de 2 kVA sont utilises pour valider les algorithmes et les techniques de commande proposes.

Space vector modulation based switching schemes for high frequency link matrix rectifier in discontinuous conduction mode

“…Since we are focusing on the DCM operation, the DCM is defined as the highfrequency current becomes discontinuous at zero vector period. [11,13,17,24,26,27].…”

“…For the current source converter, the current space vector is used for modulation [15, 24, 25]. As shown in Fig.…”

“…6–8 are named as switching schemes LA, LB, LC, LD, LE, and LF. The basic switching schemes HA, HB, HC, HD, HE, LA, LB, LD, and LE have been presented in previous work on HFLMR [11, 13, 17, 24, 26, 27]. The new switching schemes LC, HF, and LF are proposed for this converter to form a comprehensive comparison.…”