Design and implementation of internal model based controllers for DC/AC power converters

The aim of this thesis is to design and implement an advanced control system for a working three-phase DC to AC power converter. Compared to the traditional PI controller used widely in industry, the new voltage controller can track the reference voltage with improved accuracy and efficiency in the presence of different kind of local loads, and also works well in the single phase voltage control. This voltage controller is combined with a power controller to yield a complete controller. An important aspect of this work is the hardware implementation of the whole system. Main parts of this thesis are: 1. Review of H-infinity and repetitive control techniques and their applications in power converters. 2. Design of a new voltage controller to eliminate the DC component in the output voltages, and taking into account the practical issues such as the processing delay due to the digital signal processor (DSP) implementation. 3. Modelling and simulation of the converter system incorporating different control techniques and with different kinds of loads. 4. Hardware implementation and the two-processor controller. The parallel communication between the DSPs. 5. The main problems encountered in hardware implementation and programming. The software used to initialize DSPs, implement the discrete time voltage controller and other functions such as generations of space vector pulse width modulation (SVPWM) signals, circuit protections, analog to digital (AD) cOl)versions, data transmission, etc. 6. Experimental results under circumstances of no load connected to the converter, pure three-phase resistive loads, three-phase unbalanced resistive loads and the series resistor-inductor loads.