Abstract:
Single-phase PWM AC/DC converter used for Microgrid application has been widely tested mostly using linear loads. The behaviour of the converter with the linear and static/dynamic loads need to be analysed when it is connected to the grid, particularly with the Indian house hold power supply. This thesis presents simulation and experimental results to verify the behaviour of PWM AC/DC converter with different loading scenarios lighting loads, resistive loads and BLDC motor load.All experiments conducted on scenario based approach and are performed on real time digital simulator test bed, to evaluate the converters performance in real time. The study analyses the effects of DC and AC bus during the instants of switching and their response to the sudden load changes. The converter parameters are chosen in such way that to have good efficiency and cost effective. In addition to this, same converter can be used for the reactive power compensation. The existing control topologies are showing the best performance for one or two operation modes (i.e. rectification, inversion and reactive power compensation) and will not perform well for all the modes. The control strategies are not differ much, only there is slight change in control loops and switching schemes.
This thesis presents the improved control strategy with the idea of switching the optimal control schemes for the particular operation by taking individuals scheme benefits. That means it adopt reduced switching loss PWM scheme, when the UPF current waveform is desired in either rectification or inversion mode and it also can supply or absorb reactive power in both the modes by using modified PWM scheme during reactive power support. The control circuit is implemented using hardware in loop (HIL) platform.