The Design And Implementation Of Control Algorithm Of The Off-grid Battery Storage Inverter

With the rapid development of micro-grid power supply system and higher requirement of the power quality for the load, the off-grid technology for power inverter is widely concerned. To the single module, synchronously rotating reference frame can conver AC to DC to realize PI control with zero steady-state error. It overcomes the deficiency of the traditional PI control. To system paralleled, virtual inductance makes equivalent output impedance as pure inductive(L-type), pure resistance(R-type) or pure capacity(C-type), decoupling active power and reactive power.Output power of every single power module of energy storage inverter can be balanced by droop Control strategy.1) In this paper, through comparison and analysis of PR control under two-phase stationary coordinates and PI control under two phase rotating coordinate, obtained that the latter control performance is more superior to the former conclusion and Select the control algorithm that the control performance is relatively good to design.2) Through using the root locus method analysis the worst load conditions.and combining with the Routh criterion to select the control parameters, we can ensure that the system is stabl when the loads change from zero to infinity.3) This paper analyzes the influence of current inner loop to control the performance, and comparative analysis the advantages and disadvantages of single voltage loop control or double closed loop control, and solves the system under the condition of extreme mutation load voltage overshoot volume that is too high.4) this paper put forward the droop control method based on pure perceptual and capacitive.this paper analyze the drooping characteristics of pure perceptual, pure sex, pure capacitive droop and put forward The realization of the virtual inductance and capacitance method To solve the power voltage deviation caused by the problems in the process of droop control.5) The conclusions and control strategies proposed in this paper are verified using MATLAB /simulink and actual experimental platform, explaining their effectiveness.