| The thesis focuses on a novel matrix converter family - dual-bridge matrix converter (DBMC). Theory analysis, simulation and experimentation are made to investigate its character. Following conclusions are made:; The DBMC family has several advantages to become an option in the industry. Compared to the conventional matrix converter, it possesses the same high performance such as high quality input/output waveforms, adjustable input power factor, and no large energy storage component. Moreover, it has more advantages than the conventional matrix converter. Firstly, it has simpler and safer commutation; secondly, several topologies with reduced number of switches can be derived for different load; thirdly, it has simple clamp circuit. A clamp circuit with only one diode and one capacitor is developed and applied in this thesis.; Using the same PWM method of the DBMC, the thesis proposes a novel robust commutation scheme without any current information for the conventional matrix converter. With this scheme, the converter operates like a conventional DC/AC inverter during operation and an uncontrolled diode rectifier while the converter is shut down. The conventional matrix converter can operate safely without any clamp circuit under normal operation.; Simulation shows that, the DBMC has higher efficiency while either the load power factor or the output voltage amplitude is low. However, when the output load has higher voltage amplitude and higher load power factor, the efficiency of conventional matrix converter is higher.; The thesis proposes a new clamp circuit to protect the 9-switch DBMC under low output power factor. Simulation and experimental results shows that the 9-switch DBMC can still provide high quality input/output waveforms when the output power factor is not too low.; Finally, the thesis proposes a new unbalance compensation scheme for the DBMC. With this method, the unbalances in the line side of the converter can be effectively blocked without degrading the input current waveform. Moreover, this scheme is simple. It needs only to detect the fundamental component of the source voltage. |
