| The development of power electronics brings us more and more equipments based on power converter. These equipments supply us with lots of convenience; meanwhile, our power grid is polluted by the harmonics caused by those power equipments. At present, most power converters adopt uncontrollable diode rectifier and phase-control thyristor rectifier which also produce current harmonics and low power factor. Modern power converter based on PWM (pulse width modulation) technique has high power factor and can be operated in four quadrants. It enjoys more and more application in power grid system because of its lower harmonics and steady dc voltage.In this dissertation, voltage source PWM converter's four-quadrant operation and topology was analyzed from the principle of PWM converter. Low-frequency and high-frequency mathematic model of PWM converter were built in three-phase stationary frame, two-phase stationary frame and two-phase rotary frame respectively. PWM converter's indirect and direct current control technique were analyzed and studied. The gist of designing AC side inductance and DC side capacitor was offered. The design of outer voltage-loop and inner current-loop based on dual-loop control strategy was analyzed and studied.Vector control based on grid voltage orientation of three-phase PWM converter was studied and PWM converter's operation as rectifier and inverter was simulated. Its control strategy without grid voltage sensor and under unbalanced grid input was also analyzed and studied. Two control schemes, virtual flux control and positive & negative sequence dual-loop control, were adopted respectively. Corresponding simulation was done and turned out to be of good performance. Finally, experiment platform based on TI DSP TMS320F2812 was built and validation experiment was done to validate the correctness of proposed schemes.
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