Modeling And Control Of Dual-PWM Converter

Dual-PWM converter is composed of two voltage source converters, which are based on full controlled power electronic devices back-to-back, and the voltage of DC side is supported by capacitors. The device has several marked advantages, such as two-way energy, independently controlled reactive power, adjustable power factor, low harmonic output voltage, adjustable voltage of dc side and so on. Therefore, it has been widely used in DFIG, HVDC Flexible and variable frequency speed regulation. In this paper, common problems of Dual-PWM converters transferring energy between the same frequency and different frequency systems are researched.The topics involved are as follows, analyzing the principles of Dual-PWM converter; establishing the model based on three-phase coordinate system and in the rotating dq coordinates; demonstrating the inverse model control strategy between two active networks and between active network and load, both under normal working condition and in the startup process, with current control as inner-loop and power control as outer-loop; PWM wave digitization and its realization with regular sampling to control IGBT triggering pulse; building simulation platform based on PSCAD/EMTDC to validate the control policy. The results show that controllers designed well satisfy the control strategy and the stability.