The Research On The Power Coordinated Control Strategy Of The Before And After Converters In The Back To Back System

Today, people are concerned about the energy crisis and the environment deterioration, such as solar, wind and other clean renewable energy of concern. Meanwhile, with the rapid development of semiconductor devices and the power electronic technology, which is possible, are used in new energy. In this paper, the two-level back-to-back converter as the background to study power electronic converter, it is proposed that before and after the back-to-back system power coordinated control strategy, and verified by experiment.Firstly, the introduction of back-to-back converter used in wind power converter, flexible DC transmission and distribution network to improve low voltage microgrid voltage quality, energy storage system and AC-DC-AC speed control system. It is introducted that research status of the converter, topological structure, the control strategy research, and the modulation method and system main control chip development. Two-level back-to-back system hardware circuit designs, the selection of power devices and filter inductance capacitance, and DSP control circuit is designed.Secondly, the introduction of the structure of permanent magnet synchronous motor (PMSM), physical and mathematical model under different coordinate system, the common control strategies and rotor storage energy as a double closed-loop feedback control strategy, and some key technologise research. Presents mathematical model under the different coordinate of the PWM rectifier, commonly control strategies and the dead-beat control (DBC) strategy on αβ coordinate, and key technology research.Thirdly, the power coordinated control strategy of the system and experimental platform are designed, including programs design of diode rectifier charging, grid voltage phase-locked, energy loop and power inner loop, the PMSM with brushless startup, rotor position and speed calculation, the speed loop and current inner loop.Finally, according to the above control strategy and the design of hardware and software, building the two-level back-to-back system experimental platform at laborator. Through experimental results of power coordinated control, validating the correctness and effective of the proposed strategy.