Research Of Low Voltage Ride-through Of Inverter Based On Super-Capacitor

The inverter has the characteristics of high efficiency and flexible control,and is widely used.However,low voltage protection tripping often occurs due to grid voltage dips,causing the equipment not to operate normally and resulting huge economic losses.The energy storage device can enable the inverter to complete the low voltage ride-through in the low voltage area of the pow er grid,so as to keep the equipment stable operation and not stop due to the voltage dips of the grid.Therefore,it is of great significance to research the low voltage ride-through method of inverter for the safe and stable operation of equipment and economic benefits.This paper researched the low voltage ride-through method of low voltage frequency inverter.by introducing the super-capacitor as the energy storage device,an isolated bidirectional full-bridge DC/DC converter is constructed and controlled by the double closed-loop voltage-current loop.The low-voltage side of the bi-directional converter is connected to the super capacitor,and the high-voltage side is connected to the inverter DC bus,The converter acts as a bi-directional flow interface to control the energy management of the super-capacitor,when he grid voltage dips,the capacitor discharges to maintain the voltage stability of the inverter bus,Its short charge and discharge time and high efficiency high power density,and easy maintenance,make it suitable for low voltage ride-through applications.The simulation model was bult in PSIM,The simulation results show that the super-capacitor can make the inverter complete the low-voltage ride-through,and the inverter can still keep the stable operatnon when the voltage of the power grid dips,which proves that the low-voltage ride-through method is correct,effective.Finally,built a bi-directional full-brideg DC/DC converter experiment platform with TMS320F28335 DPS as the core,connected to the inverter DC bus,design the hardware circuit,and respectively tested.Wrote the super capacitor discharging control program,and conducted an experimental verification.