The Design And Research Of Dynamic Voltage Restorer Based On Super Capacitors Energy Storage

Voltage dips is the greatest harm and the most possible happen for the power system of all dynamic electric quality problems. So we must take measures to control it. Dynamic voltage restorer (DVR) is considered the most effective way to solve voltage instantaneous dips harm, DVR connects with the load in series, and DVR along with load access to the grid. Super capacitors as a novel energy storage component, having a high energy density, charging and discharging rapidly, having a long service life, as such, super capacitors energy has attracted many people’s attention. Using DVR contain super capacitors energy storage to avoid voltage instantaneous dips is very sensible.In view of the grid voltage dip, this thesis designs a new structure dynamic voltage restorer based on super capacitors energy storage. Puting forward a new method of detecting voltage dips. Research the control technology of super capacitors charging and discharging energy storage. In this thesis, the main job could be shown as follows:(1)Research on the dynamic power quality problems systematically according to the characteristics of voltage instantaneous dips, analysis the principle of super capacitors charging and discharging, describing the main structure of dynamic voltage restorer based on super capacitors energy storage.(2)Complete the device hardware design and software design, hardware design including equalizing super capacitor charge and discharge circuits, DC-DC transformers circuits, full-bridge inverter circuits, sample conditioning circuits, the main control unit circuits, etc,. Software design including the main program, AD, timer interrupt, protection programming, etc,. Texting for this device, which results is nice.(3)Put forward a new algorithm based on αβ-dq continuous derivation detection firstly. Making theoretical analysis and simulation on the new algorithm, this algorithm real-time performance is very nice, whilemean it could quickly determine the power grid occur dip in the microsecond level. In order to eliminate the derivative algorithm "overshoot response" cause noise, this thesis put forward the corresponding accumulated optimization way combined with digital sampling technology, which experimental effect is obvious.(4)Research on the characteristics of super capacitors charging and discharging, combined with Bi-directional DC-DC circuit, through a small signal modeling to develop a double-loop control strategy,which achieving super capacitors constant current followed by constant voltage charging mode and achieving constant voltage discharge mode. Calculate the controller parameters based on automatic control theory in detail. And proposes the method of super capacitors charge current change then constant voltage, as well as proposes the method of super capacitors discharge segmented voltage regulator. Do some simulation by the MATLAB, verificating the new ideas is correct. By the way of using the new control strategy, the effect of super capacitors charging and discharging significantly improved.