جستجوی مقالات مرتبط با کلیدواژه « Voltage Source Converter » در نشریات گروه « برق »

Active power filters (APFs) play a vital role in reducing the current harmonics and improving power quality. This work studies a shunt APF (SAPF) based on the three-phase voltage source converter (VSC). This paper investigates the new robust control approach using error dynamics. Stable first-order error dynamics are considered when designing the control inputs. Three control inputs are obtained to control the currents at any phase by choosing and optimizing the appropriate parameters. This strategy is also simple to implement in practical applications because it is the same as the proportional-derivative controller design. In addition, the new control method can be utilized for any system with low dynamic information so that the destructive effects of lumped uncertainties in the output channels of the SAPF can be alleviated. The minimum voltage and current measurements are used to control the SAPF, and the grid current harmonics will be reduced by achieving the stabilization of tracking error dynamics. Some numerical simulations are performed by MATLAB software to confirm the proposed method.

The most crucial approach for power and control system implementation is optimal power flow because it yields the lowest operating costs and maintains the safety margins for the control variables. An essential component of the flexible AC transmission system (FACTS) is the unified power flow controller (UPFC). It is designed to provide multiple types of energy system compensation and can be utilized for controlling the reactive and active electrical power in transmission lines and bus voltages independently and at the same time. Considerable studies have been published in the UPFC engineering applications area using various techniques. Due to its versatile capabilities, UPFC is recognized as one of the most promising FACTS devices for modern power systems. UPFC is used to improve reactive power mismatch control and system stability. A brief review of UPFC applications for increasing power system flexibility and controllability has been conducted and summarized. This paper also discusses the utilization of artificial intelligence in the placement of UPFC in power systems.

The Direct power control and vector control of DFIG has known advantages, but certain disadvantages like steady state performance and transient performance of the system still persist. In order to overcome these, a novel technique based on Improved Sensorless Rotor Position Computational Algorithm with Integrated Direct Power and Vector Control (IDPVC) for S-VSC interfaced DFIG is proposed in this work. The advantages of both vector control and direct power control techniques are addressed in this method. This proposed IDPVC control minimizes the real and reactive power ripples at steady state and total harmonic distortion in stator current. In the proposed control, data acquired from sensorless rotor position computation makes the system more stable and avoids the sensor maintenance and feedback errors. The proposed system is tested for a 3.73 kW DFIG and compared with a benchmark DPC control of single VSC based DFIG. The results show the effectiveness of the approach under various wind speed conditions and found to be satisfactory.

Nowadays, renewable energy sources such as photovoltaic and active generators are utilized frequently in modern power systems especially micro-grid. By providing electrical energy using micro-grid systems, the reliability and quality of the system can be improved. A micro-grid connected to the network depends on the main grid and consequently assessing the power quality during independent functioning (islanded mode) is important. The aim of the present work is to perform active, reactive power distribution strategies (control) for active generators used in smart grids. The proposed control method is the sliding mode which controls the active as well as reactive power and frequency. Here, based on sliding mode control method, droop control is developed for active generator. This controller is simulated for active generator by MATLAB/SIMULINK and simulation results are given. Based on the obtained simulation results, efficiency of sliding mode in regulating active and reactive power and controlling domain voltage and frequency are shown.