A new control method for Dynamic Voltage Restorer with asymmetrical inverter legs based on fuzzy logic controller
ABSTRACT Dynamic Voltage Restorer (DVR) is used in power distribution system to protect sensitive loads in voltage disturbances. The performance of DVR is related to the adopted configuration and control strategy used for inverters. In this paper, an asymmetrical voltage-source inverter controlled with fuzzy logic method based on hysteresis controller, is used to improve operation of DVR to compensate voltage sag/swell. Simulation results using MATLAB/Simulink are presented to demonstrate the feasibility and the practicality of the proposed novel Dynamic Voltage Restorer topology. Total Harmonic Distortion (THD) is calculated. The simulation results of new DVR presented in this paper, are found quite satisfactory to eliminate voltage sag/swell.
Conference Proceeding: Control strategies for dynamic voltage restorer compensating voltage sags with phase jump[show abstract] [hide abstract]
ABSTRACT: Voltage sags are an important power quality problem and the dynamic voltage restorer is known as an effective device to mitigate voltage sags. In this paper, different control strategies for a dynamic voltage restorer are analyzed with emphasis put on the compensation of voltage sags with phase jump. Voltage sags accompanied by a phase jump are in some cases more likely to trip loads and a satisfactory voltage compensation are more difficult to achieve. Different control methods to compensate voltage sags with phase jump are proposed and compared. Two promising control methods are tested with simulations carried out in Saber and finally tested on a 10 kVA rated dynamic voltage restorer in the laboratory. Both methods can be used to reduce load voltage disturbances caused by voltage sags with phase jump. One method completely compensates the phase jump, which is the best solution for very sensitive loads. The second method does only partly compensate the phase jump, but it is expected to have a better performance in compensating a broader range of voltage sagsApplied Power Electronics Conference and Exposition, 2001. APEC 2001. Sixteenth Annual IEEE; 02/2001
Conference Proceeding: Dynamic voltage restorer based on voltage space vector PWM control[show abstract] [hide abstract]
ABSTRACT: A dynamic voltage restorer (DVR) based on the voltage space vector PWM (VSVPWM) algorithm is presented. Phase jump compensation is achieved using a software phase-locked loop (SPLL). A battery charging control technique using the DVR itself is also described. To validate the control of DVR, a three-phase prototype with a potential power rating of 10 kVA has been successfully developed. Simulation and experimental results are shown to validate the control methodsApplied Power Electronics Conference and Exposition, 2001. APEC 2001. Sixteenth Annual IEEE; 02/2001
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ABSTRACT: Dynamic voltage restorers (DVRs) are used to protect sensitive loads from the effects of voltage sags on the distribution feeder. This paper presents and verifies a novel voltage sag detection technique for use in conjunction with the main control system of a DVR. In all cases it is necessary for the DVR control system to not only detect the start and end of a voltage sag but also to determine the sag depth and any associated phase shift. The DVR, which is placed in series with a sensitive load, must be able to respond quickly to a voltage sag if end users of sensitive equipment are to experience no voltage sags. A problem arises when fast evaluation of the sag depth and phase shift is required, as this information is normally embedded within the core of a main DVR control scheme and is not readily available to either users monitoring the state of the grid or parallel controllers. Previous research presented an additional controller, which required phase and sag depth information to manipulate the injection voltage vector returned by the main controller in order to prevent the DVR injection transformers from saturating. Typical standard information tracking or detection methods such as the Fourier transform or phase-locked loop (PLL) are too slow in returning this information, when either applied to the injection voltage vector, or to the supply voltages directly. As a result of this the voltage sag detection method in this paper proposes a new matrix method, which is able to compute the phase shift and voltage reduction of the supply voltage much quicker than the Fourier transform or a PLL. The paper also illustrates that the matrix method returns results that can be directly interpreted, whereas other methods such as the wavelet transform return results that can be difficult to interpret.IEEE Transactions on Industry Applications 02/2004; · 1.67 Impact Factor