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Voltage-controlled inverters have been widely used in distributed generation due to their flexibility and smooth transition between grid-connected and islanded modes. However, in the grid-tied mode, the inherent coupling between active and reactive power will challenge the independent control of active power and reactive power, and therefore deteriorate system performance. To deal with this issue,...
With a still increase of grid-connected Photovoltaic (PV) systems, challenges have been imposed on the grid due to the continuous injection of a large amount of fluctuating PV power, like overloading the grid infrastructure (e.g., transformers) during peak power production periods. Hence, advanced active power control methods are required. As a cost-effective solution to avoid overloading, a Constant...
This paper presents an overview of the predictive control principles applied to matrix converters and also the different topologies where this control technique is applied. It will be shown that the predictive strategy is a promising alternative to control matrix converters due to its simplicity and flexibility to include additional aspects in the control being suitable for different industrial applications.
A reconfigurable photovoltaic system based on the structure is developed by combining a single-phase quasi-Z-source inverter and the grid-connected system, and a digital signal processor is used to implement the indirect current control algorithm of the quasi-Z-source inverter. The DC bus voltage and the output voltage can be effectively regulated by shoot-through and nonshoot-through modes. In addition,...
In this paper a permanent magnet synchronous generator based wind energy conversion system (WECS) with 2 level back to back converter under normal and fault condition on grid side is studied by using two effective controllers i.e tip speed ratio (TSR) and Fuzzy logic control (FLC) for maximum power extraction. The control schemes are used to track maximum generator power and to protect the wind turbine...
The predictive strategy is a promising alternative to control matrix converters and due to its simplicity and flexibility to include additional aspects in the control, its implementation can be extended to different topologies and industrial applications. This paper presents an overview of the predictive control principles applied to matrix converters and other derived topologies including cascade...
In this paper, three different techniques which can be used for control of three phase PWM Rectifier are discussed. Those three control techniques are Direct Power Control, Indirect Power Control or Voltage Oriented Control and Hysteresis Control. The main aim of this paper is to compare and establish the merits and demerits of each technique in various aspects mainly regarding switching frequency...
This paper deals with direct control of active and reactive powers in a doubly fed induction generator (DFIG). The stator flux space vector is firstly estimated in the stationary reference frame and then transformed to the rotor reference frame. The suitable rotor voltage space vector is calculated using a switching table based on the errors in stator active/reactive powers. The ordinary direct power...
This paper presents the powers control of a variable speed wind turbine based on a doubly fed induction generator (DFIG) connected to the electric power grid. In order to control the active and reactive power exchanged between the stator and the grid, a vector control (with stator flux orientation) is used with PI controllers. The main objective of this paper is to compare the performance of the open...
this paper presents an improved deadbeat direct power control (DPC) for grid connected voltage source converters (VSCs). The proposed deadbeat-DPC combines a deadbeat control law with a full order Luenberger observer to predict the converter behavior. The deadbeat control law is chosen to cancel out the power error and the Luenberger observer is adopted to compensate for the control delay and simultaneously...
This paper proposes a novel voltage control method for cooperative-autonomous switching control. In power systems, the presence of a large number of photovoltaic (PV) systems in a small district leads to deviations in voltage from the upper limit of the specified voltage range. Autonomous active power control leads to inequalities of the PV generation power on the same distribution line. Cooperative...
This paper presents a new control scheme for a multi-terminal low frequency ac transmission system (LFAC) operating with a cycloconverter. The multi-terminal sytem uses two-phase LFAC system with a 12-pulse thyristor converter. A control scheme for power control by Virtual Synchronous Generator (VSG) among each terminal is explained in detail to understand the advantages of this method. Circuit configurations...
Simulation tools are necessary to research and develop modular multi-level converter (MMC) based HVDC systems for the future power grid. Real-time simulators offer the ability to connect to real physical equipment in a hardware-in-loop (HIL) scheme to test and design controllers, protection systems and encompass the complete operation and response of an HVDC system. The complexity of an MMC valve...
Islanded DC microgrid architecture and control have become popular recently. One of the main control architectures is the DC bus voltage following type, where a main generator controls the DC bus voltage and the others follow the bus voltage and the power commands. Conventionally, the power regulation in the following generators is often employed with the droop control method. The main problem of...
This paper proposes a power balancing strategy for dispatchable and non-dispatchable sources in an islanded microgrid. This control method enables energy storage system that employs a voltage-band at a dc busbar to maintain grid voltage stability for short period disturbances in a network. This voltage-band, applied to obtain maximum benefit from the storage system, depends on a storage capacity feature...
In this paper, the most prominent inverter interface control techniques for the grid-connected photovoltaic (PV) systems; the constant-current control (CCC) and constant-power control (CPC) were evaluated based on the dynamics of the inverter local load. A fully controlled 100 kW grid-connected PV distributed generation (DG) with dynamic load is simulated in MATLAB Simiilink. The CCC has one fast...
This paper proposes the use of a transformer-less DC-DC Modular Multilevel Converter (MMC) topology, based on cascaded H-bridge converters, for power flow control in High Voltage Direct Current (HVDC) grids used to connect off-shore wind power plants to on-shore grids. An energy based approach is used to regulate the DC voltage of H-bridge modules. Results for the operation of the DC-DC MMC supplying...
Single-switching-vector-per-sampling-interval character of the classical Direct Model Predictive Power Control (DMPPC) technique leads to big ripples of the control variables. Therefore, with a similar sampling frequency, its steady state performance is not satisfying. This work proposed a Revised Direct Model Predictive Power Control (R-MPDPC) concept for grid-tied AFEs. Instead of one single switching...
To improve the design of a power control unit at Philips, two Domain Specific Languages (DSLs) have been used. The first DSL provides a concise and readable notation for the essential state transitions. It is used to generate both configuration files and analysis models. In addition, we also generate instances of a second DSL which represents test traces. This second DSL is used to generate test cases...
A passivity-based power control method is proposed for the three-phase three-level NPC rectifier in this paper. The decoupled control of active and reactive power of the three-level NPC rectifier in the dq reference frame can be realized by the proposed method. The neutral point voltage is controlled by adjusting the dwelling time of the small vectors. The proposed modeling and control strategy are...
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