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To ensure safe and reliable operation of power system based on wind energy, usually plant operators should satisfy grid code requirements such as grid stability, fault ride through (FRT), power quality improvement, grid synchronization and power control etc. To satisfy the grid code requirements of wind turbine, usually grid side converter is playing a major role. So in order to improve the operation...
This paper introduces a new cost effective structure of a 4-switch single-phase to three-phase converter using a Quasi Z-source (QZs) network for induction motor drive applications. In comparison to the traditional 6-switch structure, the proposed circuit reduces the cost of the system, switching losses and the complexity of the control method as well as the interface circuits used to make the trigger...
In this paper, a high gain single-stage buck-boost grid-connected system is proposed. The proposed system consists of a high voltage gain - high efficiency - switched inductor buck-boost converter (SIBBC) and a folded cascade H-bridge inverter. The proposed converter switch is derived with a sinusoidal modulation, so that the converter output voltage is a rectified sine wave which requires only a...
Brushless Doubly-Fed Machine (BDFM) is a machine which incorporates the robustness of the squirrel cage induction machine while having the speed and power factor control of a synchronous machine. A special kind of rotor called Nested-Loop rotor plays an important part in the BDFM, coupling the two stator fields. In future BDFM will share a large part in wind power market. This paper presents a mathematical...
Doubly Fed Induction Generators (DFIG) has emerged as a suitable alternative for conversion of wind energy to grid quality energy under varying wind conditions. Often the control mechanism use large number of sensors and employ complex computations. Moreover, the reported control schemes for DFIG employing grid side converter (GSC) do not ensure a drawl of unity power factor (upf) sinusoidal current...
In this paper, authors propose a novel fourteen-band hysteresis technique to control the fifteen level packed U cells (PUC) converter. This topology was first introduced. It combines advantages of the flying capacitor and the cascaded H-bridge topologies. The study of the novel converter allows the establishment of the switches gates signals equations. In case of rectifier operation, the proposed...
This paper deals with the analysis, modeling, and control of a doubly-fed induction generator (DFIG) driven by the wind turbine. A control technique is presented for extracting the maximum power from the wind turbine. The wind energy conversion system (WECS) is equipped with a DFIG and two back-to-back connected voltage source converters (VSCs) in the rotor circuit. The proposed control technique...
This paper describes a wave-to-wire model of an array of wave energy converters developed in MATLAB/Simulink. The effects of connecting a 1 MW wave farm to a weak, rural electricity network are investigated. Impacts of the wave farm on voltage quality are examined and both conventional and more intelligent control methods by which these impacts can be mitigated are discussed. The control methods compared...
In this paper, authors propose a novel six-band hysteresis technique to control the seven level packed U cells (PUC) converter which was first introduced in. This converter combines advantages of the flying capacitor and the cascaded H-bridge topologies. The study of the novel converter allows the establishment of the switches gates signals equations. In case of rectifier operation, the proposed six-band...
The control of cascaded H-bridge boost rectifiers is a challenging task, due to the inherent coupling of the H-bridge modules. This property highlights the demand for a robust control technique, appropriate for this nonlinear and non-minimum phase system. This paper introduces an approach that combines a deeper understanding of the system's power flow with the well known robustness of the sliding...
A varying-frequency control Flyback rectifier for LED driving in Boundary-Conduction Mode (BCM) is presented. Comparing with Discontinuous-Conduction Mode, BCM has the advantages like smaller coupling inductor current, less current stress for circuit component, slight output current ripple, and higher power factor performance. For lower output application circumstance, the boundary conduction mode...
A constant current output Flyback converter with power factor correction used for LED driving is presented in this paper. The inductor voltage detection method is applied and acquired the inductor voltage to generate the control signal. Based on this design principle, the inner loop of input current shaping is eliminating, the input voltage sensing and multiplier are also not necessary. The simulation...
In this paper, a quasi sliding mode controller is proposed to control single phase PFC boost converter. The outer voltage loop is PI control and the sliding mode control is used in the inner current loop. The designed quasi sliding mode controller has advantages such as robustness when there are large variations in line voltage and output load. Moreover, the chosen sliding surface avoid the differentiator...
In the Tokaido Shinkansen, the instantaneous feeding power of substations increases because of the high-density train schedule and the improved acceleration performance of the rolling stock. If the load power of feeding substations increases further, it will not be possible to maintain the feeder voltage if the power converter supplies only reactive power. Assuming such a situation in the frequency...
In consequence of the generic irregularity of wave energy, it is difficult to envisage the performance of a grid connected wave energy converter without simulations. This paper details a study on directly driven, linear, permanent magnet generator based, wave energy extraction scheme provided with grid-connected three phase neutral point-clamped three level inverter. The linear permanent magnet generator...
This work presents a dual converter employed as a rectifier with power factor regulation and bidirectional power flow. The active and reactive power flowing into the converter is controlled using an optimized direct power control algorithm. The multilevel structure of the converter is exploited to control the voltage level in each sub converter by selecting the modulation method from one commonly...
A nonlinear average current control method using only dc-rail current for three-phase power-factor-corrected (PFC) converters was introduced recently. This paper discusses the effects of dead-time, sector synchronization, input voltage harmonic distortion and sensing delay on its control performance. A dead-time compensation scheme without additional sensing requirement that is suitable to the nonlinear...
This paper introduces a digitally-controlled off-line LED driver based on low-voltage series-input converter modules. The series-input connected modular architecture is adopted to utilize low-voltage high-frequency circuits and low-profile components in off-line applications. Input current is regulated to be constant using a simple controller to achieve 0.9 power factor (PF) without a traditional...
Three phase three level neutral point clamped (NPC) rectifier is a popular topology for power converter front-ends to achieve controllable DC voltage. In this paper, its mathematical model is analyzed and a dual-loop control strategy is adopted to regulate both DC voltage and input power factor. Instead of space vector PWM, an improved multi-level carrier based PWM is presented. The control system...
Recent faster and more frequent train service at Tokaido Shinkansen makes it difficult to stabilize the feeding voltage only by compensating reactive power. Therefore, the active power compensation between two phases has been introduced for further stabilization of the voltage, and the converter control strategy called ??fixed power-factor method?? was applied in the commercial operation that started...
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