Enhancing Doubly Fed Induction Generator Low-Voltage Ride-Through Capability Using Dynamic Voltage Restorer with Adaptive Noise Cancellation Technique

Some of the major challenges facing micro-grids (MGs) during their connection with the utility grid are maintaining power system stability and reliability. One term that is frequently discussed in literature is the low-voltage ride-through (LVRT) capability, as it is required by the utility grid to maintain its proper operation and system stability. Furthermore, due to their inherent advantages, doubly fed induction generators (DFIGs) have been widely installed on many wind farms. However, grid voltage dips and distortion have a negative impact on the operation of the DFIG. A dynamic voltage restorer (DVR) is a commonly used device that can enhance the LVRT capability of DFIG compared to shunt capacitors and static synchronous compensator (STATCOM). DVR implements a series compensation during fault conditions by injecting the proper voltage at the point of common coupling (PCC) in order to preserve stable terminal voltage. In this paper, we propose a DVR control method based on the adaptive noise cancelation (ANC) technique to compensate for both voltage variation and harmonic mitigation at DFIG terminals. Additionally, we propose an online control of the DC side voltage of the DVR using pulse width modulation (PWM) rectifier to reduce both the size of the storage element and the solid-state switches of the DVR, aiming to reduce its overall cost. A thorough analysis of the operation and response of the proposed DVR is performed using MATLAB/SIMULINK under different operating conditions of the grid. The simulation results verify the superiority and robustness of the proposed technique to enhance the LVRT capability of the DFIG during system transients and faults.

Dynamic voltage restorer using sliding mode controller: Experimental studies

The simulation and implementation of a sliding mode control strategy for a single-phase dynamic voltage restorer (DVR) to mitigate load voltage sag swell and harmonics is presented in this work. The control strategy's goal is to compensate for the required voltage by regulating the DVR's voltage via an injection transformer while keeping the load voltage constant. The ability of the DVR to achieve a good performance greatly depends on its control strategy. The controller used in this work is based on SMC theory, which consists of creating a passivation output and a storage function to use as a function of Lyapunov. The proposed control scheme of the DVR is initially evaluated in simulations using MATLAB and validated using a laboratory-scale prototype of the entire system, including a source, the DVR circuit and a load. The control scheme is implemented on a dSPACE 1104 board and the MATLAB real-time toolbox. Both the experimental results have demonstrated the effectiveness the proposed control strategy of DVR in mitigating power qualities issues and therefore enhancing the performance of the network.

Five Level Flying-Capacitor Multilevel Converter Using Dynamic Voltage Restorer (DVR)

This paper deals with dynamic voltage restorer (DVR) controlled by a five-level flying-capacitor multi level converter. To decrease the power-quality disturbances in distribution system, such as voltage imbalances, harmonic voltages, and voltage sags. The organisation of this paper has been divided into three parts; the first one eliminates the modulation high-frequency harmonics using filter increase the transient response. The second one deal with the load voltage; and the third is flying capacitors charged with balanced voltages. The MATLAB simulation results effectively for five level flying capacitor multilevel converters charged with balanced voltage regulation.