Research On LCL-Filter Of Ac-side In Four-quadrant Inverter

Rectifier circuit general purpose inverter, uncontrolled, with low input power factor, harmonics, energy irreversible defects. Two PWM converter consists of inverter, rectifier unit to replace the use of PWM rectifier bridge, reducing the harmonics generated by the inverter input, the system power factor close to1, to reduce energy consumption, enriching the inverter is functional.PWM converter device due not only to achieve rectification, DC inverter can also be close to sinusoidal current success rate factor1, two-way flow of energy, so use more widely. Connection to the grid and the L-type PWM reactors need to balance the filtering effect and inductance values should not be too big contradiction, so it is up to achieve best of both worlds. Furthermore, relatively large power rectifier, the AC side filter loss increases. To address this problem, we propose a method of LCL filter PWM inverter network side. Experimental results show that, LCL filter having high frequency harmonics better attenuation at the same harmonic system requirements, the ratio of pure inductance LCL filter choke filter to be used is smaller and therefore the dynamic response of the system faster.Articles from the principle of operation of the PWM converter review began, analyze the mechanism of four-quadrant PWM operation. Based on LCL filter, respectively, in ABC fixed coordinate system, the coordinate system and the rotating coordinate system to create a mathematical model. Introduced in L-type filter paper method for controlling the PWM control scheme used in the converter. Under axis model creation, the design of the closed-loop control method of PI. In order to improve the performance of the current track, the current regulator is based I type system design. In order to increase the capacity of outer interference voltage, the voltage regulator designed according Ⅱ type system.The article also focuses on the third-order resonance issues LCL filter system designed system parameters to determine the detailed steps LCL filter system parameters established. Finally, based on MATLAB/SIMULINK environment, create a PWM inverter simulation model to simulate the actual system, and compared the effect of damping method and passive damping destined law, simulation results show that the proposed system is designed in accordance with the theory of the article has good dynamic and steady state performance.