Abstract:
This work deals with the analysis, design, and control of grid-interfaced permanent magnet
synchronous generator (PMSG) based variable speed wind energy conversion system (WECS) for
power smoothening with maximum power point tracking (MPPT) and power quality conditioning
capabilities. The power electronic device used usually as intermediate between the wind
generator and the grid is a full rated two levels back to back converter (BTB). The BTB converter
is constituted of tow PWM converters, the machine side converter (CCM) works as a rectifier and
the grid side converter works as an inverter. Several DPC based control techniques (conventional
DPC, predictive DPC and DPC based sliding mode approach (DPC-SMC)) have been applied on a PWM rectifier under ideal and disturbed supply voltage conditions. Moreover, the sensorless
grid voltage control scheme is presented using sliding mode estimator. Two versions of sliding
mode estimator have been implemented, one for the ideal and the other for the disturbed supply
condition. After an extensive set of simulations following by experimental validation, the grid
voltage sensorless DPC-SMC technique has been introduced the best performance with high
estimation accuracy and power quality. On the other hand, in a wind energy conversion system,
the grid side inverter function is ensuring permanent and stable transmission of energy to the grid.
However, the extensive use of nonlinear loads led to decrease the quality of energy at the point of
common coupling (PCC). Thus, the idea is to extend the inverter function with a harmonic
compensation capability. Hence, analysis, design, and control of shunt active power filter (SAPF)
under ideal and disturbed supply voltage conditions were an important part of this thesis. Then,
an improved control circuit for SAPF system based on DPC concept combined with a Kalman
filter as synchronization technique has been introduced. Furthermore, a modified voltage
sensorless DPC concept based predictive model and modified sliding mode estimator has been
proposed to be applied for a SAPF. Finally, the overall circuit control of the WECS system is
based on the optimal findings, which are developed in this work. For the CCM and CCR
converters, we have been applied the DPC-SMC and the proposed DPC approach respectively, as
optimized solutions.
