Direct Power Flow Controller With Two-Phase Voltage Synthesis

In order to enhance the power transmission ability of the power grid,the power system stability,a direct power flow controller with two-phase voltage synthesis(DPFC-2PS)is proposed based on voltage vector synthesis technology.DPFC-2PS only contains a simple Buck AC unit circuit and only one-level power conversion,which can simultaneously control the voltage phase and amplitude of the transmission end of the power grid,so as to achieve flexible control of line active and reactive power.The topology of direct power flow controller with two-phase voltage synthesis(DPFC-2PS)is presented and introduces its working principle in detail.The basic regulation area of voltage phase and amplitude of DPFC-2PS compensation line is analyzed.After adding the selection switch,the voltage regulation area of dpfc-2ps compensation line increases,and it can realize 360° full range regulation.At the same time,under the condition of the unbalanced original grid line voltage,it can be known that a balanced new grid line voltage can still be obtained after each phase is connected to the compensation phase voltage through a series of formula derivation.The topology of direct power flow controller with two-phase voltage synthesis(DPFC-2PS)simulated and verified by using Saber simulation software,the main circuit and PWM control circuit simulation models are designed.The simulation results show that the compensation phase voltage of different phase and amplitude is connected in the adjustable area in series,DPFC-2PS can obtain new grid voltage with controllable phase and amplitude,no matter in three-phase balanced grid voltage or in three-phase unbalanced grid voltage.Then based on the theoretical analysis,the TMS320F2812 DSP chip is used as the control platform of direct power flow controller with two-phase voltage synthesis(DPFC-2PS).The main circuit,the driving signal synthesis circuit,the driving circuit,the amplitude sampling circuit and the rising edge capture circuit together form the core unit of the system.The schematic diagrams of related hardware circuits are drawn and its working principles are analyzed in detail.At the same time,the C program is used as the programming language and CCS is used as the development environment.and the main related programmed flow chart of the required program are given.Finally,a prototype of direct power flow controller with two-phase voltage synthesis(DPFC-2PS)main circuit and PWM control circuit simulation model is developed.the related experiments are carried out by using the principle prototype,and the experimental results of DPFC-2PS are given,which verify the correctness of DPFC-2PS theory analysis and the feasibility of control strategy.