Control of power electronics-based synchronous generator for the integration of renewable energies into the power grid
ABSTARCT :
This paper addresses a single synchronous controller (SSC) for interfaced converters with high penetration of renewable energy resources (RERs) into a low inertia power grid. The SSC is modelled based on a comprehensive dependence between each operative feature of a synchronous generator (SG) and a power electronics converter. This can properly improve the performance of the power grid in such scenarios in which large-scale penetration of RERs are detected. The main contribution of this paper is representing an exhaustive relation between active components of the proposed SSC and SG features which enables the proposed SSC-based interfaced converter to more accurately mimic the behaviour of SGs during active power generating along with providing controllable inertia. Due to containing sufficient decoupling, both components of the proposed SSC have no impact on each other, also the proposed SSC has a superior operational flexibility within a wide range of inertia from very low to high values. Thus, two closed-loop control systems are considered to separately analyse the characteristic effects of SGs in active and reactive power sharing apart from the power grid stability challenges. In addition, the impacts of active power variations on reactive power are subsequently evaluated. To further analyse the operation of the system, the effects of the virtual mechanical power (VMP) error embedded in the SSC are considered as an alternative option for assessing the power grid stability. Also, the variations of the virtual angular frequency (VAF) error are carefully deliberated for more considerations associated with the active and reactive power performance of the SSC. Simulation results are presented to demonstrate the high performance of the SSC in the control of the power electronics-based SG when high-penetration renewable energy sources are integrated into the low inertia power grid.
EXISTING SYSTEM :
? Some existing power inverter topologies for interfacing PV modules to the grid is presented.
? A control strategy for the grid interfacing inverter with hysteresis current control is developed to improve power quality.
? The grid interfacing inverter is controlled in such a manner that the combination of grid interfacing inverter along with linear/nonlinear unbalanced load appears as balanced linear load to the grid at PCC.
? When the power electronic converters are used it introduces a lot of harmonics in the system.
? On the other hand the increased use of power electronic equipments and nonlinear loads by the industries and the households together made the degradation of power quality as one of the major problems in electric industry.
DISADVANTAGE :
? In, a short-term energy buffer is added to the system through the simulation of rotor inertia which named as virtual synchronous generator since it can reduce the instability problems at the system operational level.
? The SG emulation presented in adversely impacts on the ? of switching functions in the respective designed control scheme.
? It confirms the high impact of the proper selection of the low-value inertia in the stability of the power grid with high penetration of RERs by use of the SSC.
? These evaluations have been completed by assessing the impacts of virtual angular frequency (VAF) error on active and reactive power sharing for different low-value inertias.
PROPOSED SYSTEM :
• A number of alternative concepts have been proposed for directdrive electrical generators for use in grid-connected or standalone wind turbines.
• In order to maximize the success of the PV systems, a high reliability, a reasonable cost, and a user-friendly design must be achieved in the proposed PV topologies.
• Several useful proposed topologies have been presented, and some good studies regarding current PV inverters have been done.
• This analysis should consider the total life of the proposed hydrogenstorage system including raw-material requirements, manufacturing and fabrication processes, integration of the system into the vehicle or off-board configuration, useful service life, and removal and disposal processes including recycling.
ADVANTAGE :
? In, a self-synchronized synchronverter has been proposed which can improve operation of the synchronous controller given in by reducing the complexity, increasing the performance, and decreasing the computational efforts of the controller.
? A virtual angular frequency (VAF) based on SG features has been involved in the SSC that can significantly improve the synchronous active and reactive power sharing performance of the interfaced converter.
? Moreover, zinc–bromine battery suffers no loss of performance after repeated cycling.
? A very common ac/dc topology is the half-bridge two-level VSI, which can create two different voltage levels and requires double dc-link voltage and double switching frequency in order to obtain the same performance as the full bridge.
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