| Converters are widely used those days due to the progress of power electronic technology. The PWM rectifier has gradually become the mainstream of rectification device thanks to several advantages such as:bi-directional power flow, low harmonic distortion of line current, regulation of input power factor to unity, adjustment and stabilization of DC-link voltage, reduced DC filter capacitor size. PWM rectifiers are applied by most global company (SIEMENS, ABB and other) like an AC-DC-AC converter or a DC distributed Power System.Development of control methods for PWM boost rectifier is possible thanks to advances in power semiconductor devices and digital signal processors, which allows fast operation and cost reduction. An well known method based on instantaneous direct active and reactive power theory is called direct power control (DPC), which is one of the important nonlinear control stratgies appears those years. Simulated study of state and dynamic performance for three-phase voltage-source PWM rectifier with DPC are presented in this paper.Above all, the mathematical model of PWM rectifier is established according to circuit knowledge and the composition of rectifier, based on which, the principle of rectifier has been detailed analyzed. Secondly, Switch-table-based direct power control (ST-DPC) strategy and the mechanism of the switch table has been studied, and the traditional ST is improved. The conception of virtual flux is introduced, and virtual-flux-based direct power control strategy is studied using SIMULINK software. At last, predictive direct power control technology is introduced, which realizes the combination of direct power control and fixed frequency technology. |
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