Distributed Grid Dynamic Voltage Restorer Simulate Device

With the development of modern science and technology, the implementation of automation and electrical equipment during production leads to a higher requirement on the quality of the power grid. The most common problem that affects the power quality is the instantaneous voltage drop. As a new type of power quality control de-vice, Dynamic Voltage Restorer (DVR) is the most effective economical solution to improving the power quality.The DVR was studied and designed to solve power quality problems such as the voltage sag and the instantaneous power supply interruption etc. All parts of the grid compensation system and the theory of the device were introduced. The main circuit and control circuit has been designed, tested, and verified.For the software and algorithm design part, the characteristic parameters of the voltage sag were detected by using the single-phase dq transform method. A variety of compensation algorithms which used to solve the power quality problem have been compared. And the boundary compensation method based on the full phase compen-sation method and the same phase compensation method was selected. For hardware part, the dual hardware structure with DC-AC and AC-DC-AC were used. The first stage is the power factor correction circuit which rectifies the AC voltage to DC. It can reduce the harmonic disturbance toward the power grid. The second stage is the single-phase full bridge inverter which converts DC voltage to AC and connects to the series transformer through a low pass filter.DSP TMS320F28335was used as the control unit, and it is a floating-point digi-tal signal processor of TI Company. The ePWM module, embedded in DSP, generated the SPWM wave which follows regular sampling method. The12-bitsADC module sampled the input and output signals. With the functions above, the system design was simplified and cost was reduced. This device has digital display function, with a4.3-inch colored TFT-LCD driven by CPLD, which can display the signal waveform, the spectrum characteristics, the input/output voltage, the input/output current, the power factor, the system efficiency, the operating frequency, the distortion parameters and etc.This device has a boot self-checking, input/output voltage under-voltage and over-current protection, and can automatically recover after system back to normal condition in case of over-current and under-voltage.