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In this paper, a nonlinear robust controller is proposed for the goal of power stabilization in power systems. The here-proposed approach is based on both the use of a properly-chosen sliding surface and the derivation of a disturbance attenuation condition (nonlinear L2-gain). The controller design is then applied to a single-machine-infinite-bus (SMIB) system and some simulation results demonstrate...
This paper concerns the application of modern computational control tools in a special class of power electronic circuits, namely switch-mode dc-dc converters. Specifically, we aim at developing a disturbance estimation scheme that can be used in addition to recently developed explicit MPC control schemes in order to achieve offset-free output voltage reference tracking in the presence of unknown...
This paper deals with the problem of designing a plasma current, position, and shape controller for the ITER-FEAT tokamak. Exploiting the features of the plant, we show that it is possible to design separately two control loops: a first loop which stabilizes the vertical position by means of a simple derivative action, and a second loop which drives the plasma current and the plasma geometrical shape...
An operational analysis of a multilevel active front end rectifier, which has the mitigating capability of the current harmonics generated by the nonlinear loads connected to the same power distribution bus would be presented in this paper. Undesirable conditions in the power network such as voltage unbalances and spikes can affect negatively on the operation of very sensitive electric devices. Thus...
Multi-megawatt photovoltaic (PV) power plants are widespread in electrical power systems because of the drastic decrease in the PV panel prices. The multi-string structure is considered for high power PV systems due to the increase in the overall energy conversion efficiency and the modularity when compared to the centralized topology. High power conversion can be achieved easily using parallel connection...
This paper presents a model predictive control method applied to a single phase grid-connected inverter. The method uses a discrete-time model of the system to predict the future value of the load current by using all possible voltage vectors generated by the inverter. The voltage vector which minimizes a quality function is selected. Then, use the switch state deduced by the select voltage vector...
Multi-megawatt photovoltaic (PV) power plants are widespread in electrical power systems because of the drastic decrease in the PV panel prices. The multi-string structure is considered for high power PV systems due to the increase in the overall energy conversion efficiency and the modularity when compared to the centralized topology. High power conversion can be achieved easily using parallel connection...
In this paper, a novel predictive direct power control (PDPC) strategy is proposed for three-phase AC/DC converters, which is based on a straightforward regulation of instantaneous active and reactive power. The converter controlled by the proposed strategy realizes operations without line-side voltage sensors by introducing the virtual flux (VF) concept and a grid voltage estimation method based...
In this paper, the design of the 0°∼360° FET analog phase shifter is presented. By changing the gate voltages of the FET transistors, the output amplitudes of the four orthometric vector signals of the phase shifter can be independently adjusted. In this way, any phase shift over the range of 0° to 360° can be achieved. Due to the amplification characteristic of the FET transistors, the designed phase...
Critical production processes in industry require the drives to smoothly ride-through during momentary power interruptions. This paper presents a method to extend the duration of the ride-through for VSI-fed vector controlled induction motor drives with a front end diode bridge rectifier. The proposed method minimises the losses in the system during the ride-through thereby enabling a longer ride-through...
This paper presents a performance comparison study between the space-vector and carrier-based PWM techniques used for neutral point clamped (NPC) 3-level inverter. A reduced switching loss based modulation technique is used for the SVPWM scheme and a third harmonic injected PWM technique is used for the carrier-based PWM scheme. A 110 kW surface-PMSM is used with the NPC inverter, as generally being...
Three-phase pulse width modulated (PWM) front-end converter (FEC) has now become an essential part of many power electronic systems such as uninterruptible power supplies (UPS), battery chargers, and motor drives, etc. This paper presents simulation analysis of two-level front-end boost-converter which employs current error space phasor based hysteresis controller. The proposed controller is an effort...
Model Predictive Control (MPC) includes a mathematical model of the controlled system. Based on this model optimal actuating variables for future timesteps are determined in every sampling step. Thus the MPC exhibits a better response to a setpoint step compared to conventional control. In this paper a Model Predictive Control method for nonlinear systems with inherent output saturation is presented...
In this paper, a Diode Clamped Multilevel Topology operating in Rectifier mode is presented. A simple voltage control strategy is implemented in order to control the DC-link voltage at the output side of the rectifier. A Level shifted Carrier based Sine PWM or SVM techniques can be incorporated to generate switching signals to the devices of Five-level configuration. For Diode Clamped Converter if...
Space vector modulated voltage-source inverters require an overmodulation algorithm for continuous control of line-side voltage during overmodulation and for a smooth transition from PWM to six-step mode. Overmodulation increases the dc bus utilisation of a voltage source inverter, but requires significantly higher computational effort than linear modulation. This paper proposes a novel single-zone...
Dynamic Voltage Restorer (DVR) injects a compensated voltage to mitigate undesirable impacts on critical loads due to voltage sag/swell. In this work the controllers for DVR is proposed in stationary reference frame and injects a voltage which is in phase with the positive sequence of grid voltage. The method for load reference generation for stationary reference frame control is highly determinantal...
The major part of the existing research works concerning variable speed wind turbines control is not only to capture the maximum power from the wind but, also, to improve the quality of power and to converge the system for operating at unity power factor. This paper proposes a new power control of a variable speed wind energy conversion system based on a doubly Fed Induction Generator (DFIG) using...
This paper proposes an efficient neutral point control algorithm for three level T-type inverters. The proposed algorithm helps to get balanced neutral point voltage with high efficiency steady state operation. The proposed controller relies on using the hysteresis control for DC link capacitors' voltage balancing. The proposed algorithm is implemented by adjusting the type of redundant small vectors...
This paper introduces the advanced control designed for the single-phase AC/DC traction converter. This type of control provides direct current control and sufficient control of output voltage. The proposed control strategy is based on second order general integrator phase locked loop (SOGI-PLL), which is used for trolley voltage synchronization. In this case SOGI-PLL evaluates voltage position, amplitude...
Reactive power dispatch (RPD) is a non-linear, mixed integer optimization problem which optimizes grid congestion by minimizing the real power losses and voltage deviation for a fixed economic power dispatch. This paper proposes an efficient and reliable soft-computing technique based on differential evolution (DE) method to solve the RPD problem. Classical DE sometimes suffers from the problem of...
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