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Parallel inverters are commonly adopted in high power applications, for instance wind energy system, smart transformer, and power conditioners. Meanwhile, interleaved PWM is usually considered as an optimal approach to reduce the current ripple and harmonics of the parallel inverters. However, in case of a common dc-link, the problem of circulating current emerges and leads to performance degradation...
This paper is proposed to convert the Solar PV DC voltage into AC voltage by using 3 phase inverter and getting sinusoidal AC output voltage. To convert solar PV which is in DC needs to be converted into AC by using the devices like 3 phase inverter and boost converter. The solar PV is a variable DC that is to be converted into pure DC for which will convert variable DC to pure DC. The MPPT is designed...
Current controlled inverters need to be dynamic and robust even under grid disturbances and different grid faults. Besides a robust control method the requirements for synchronization of the system become more and more important especially when multilevel inverter topologies are used. The combination of direct current control methods and advanced grid synchronization techniques promise excellent working...
In the simulation of power electronics systems, for reasons of computing time and convergence, it may be necessary to use ideal components which generate ideal voltage switchings (steep edges). However, in reality, these voltage variations are far from ideal and to reproduce a voltage closer to reality, it is necessary to model these variations. This is especially important for the study of residual...
The paper presents a comprehensive approach to the compensation of phase current distortion of grid-connected power inverters. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, voltage fluctuations in the dc link, time delays in the estimation of grid voltages, and the distortion of inverter output voltages due...
The main contribution of this paper is to describe a robust Phase-Locked-Loop approach for three phase generation system with power flow control. This method, which is used to synchronize the inverter and the network voltages, is based on a comparison between the grid and the inverter angular positions, and correction of modulator period. The Solution presented in this paper is applied to the three...
In some cases it is unavoidable that part of the rooftop PV array is periodically shadowed by an adjacent object, greatly reducing yield. Usually, the time and amount of shadowing is known, and is considered as extra loss due to the location. Module Integrated Converter (MIC) systems are known to be a good solution for such cases, having the potential to increase the yield with as high as 25%, although...
CERN is studying the implementation of high power active front ends, implying the operation of a voltage source inverters connected to a grid that can be considered as weak when compared to the converter nominal power. Proper synchronisation is a key point for current control stability. The handling of networks with asymmetric disturbances implies the accurate handling of the second harmonic component...
Intentional islanding of distributed generation systems requires seamless transition of power between grid connected and islanding modes, ensuring little or no disruption to the local loads. This paper conducts a detail study regarding the factors affecting seamless transition. A control scheme for grid connected and islanding mode of operation with a passive islanding detection algorithm, synchronization...
This paper focuses on the performance evaluation of grid-connected photovoltaic (PV) inverters in terms of static maximum power point tracking (MPPT) efficiency. A simple test-bench set-up is proposed to accurately analyze the behavior of commercial inverters applied to PV plants under partial shading conditions. The system performs a real-time monitoring of the operating point of the PV plant during...
This paper describes a simple grid current control method for the grid-connected operation, and inverter voltage control method based on the phase locked loop (PLL) for the intentional islanding operation at the three-phase grid-connected inverter. The PLL controller based on the pq theory with a simple P-controller is used to synchronize the phase of inverter output voltage with a grid voltage at...
Lately the integration of Distributed generation systems privileging renewable sources for offshore regions is growing to view a reduction of air pollutant emissions. Due to the intermittency of Renewable Energy Sources (RES) it must be necessary to develop a quality advanced control of the involved power interfaces to warrant the frequency and voltage required by ac off-shore loads taking into account...
A new voltage synchronization scheme is proposed for parallel connected inverters in AC microgrids. Instead of using the same reference voltage for all inverters, this scheme directly synchronizes the reference voltage of a connecting inverter to the point of common coupling voltage. Two contactors are used with each inverter module to enable the inverter to operate in 4 different modes. Voltage synchronization...
Smart Grid is being considered in power systems industry for its vast potentials in providing numerous benefits that include efficient management, self-healing of the network and dynamic pricing. Such a concept can also be applied in managing grid networks that contain renewable energy sources such solar panel, wind and biogas based plants. Renewable energy (RE) sources and the related technology...
This paper presents a voltage fundamental wave recursive DFT algorithm applied in grid-connected inverter pre-synchronization. The algorithm not only is able to reliably track the voltage fundamental phase, frequency and amplitude, but also reduces the calculating consumption to guarantee real-time algorithm. Based on the equal-angle interval sampling technique (EAISP), the algorithm can adjust the...
This study proposes a soft switched Output Current Sourcing (OCS) grid connected inverter that applies a high frequency isolation transformer. Current sourcing at the output implies that, ideally, the injected current will be independent of the load voltage. The current injected to the line is controlled by varying the switching frequency and PWM at low currents. The system does not require the sensing...
This paper presents the modeling and simulation studies for the startup of a 250 MVA pumped storage unit in pumping mode and the startup of a 65 MVA hydraulic unit as a corrective action following an uncontrolled islanding of an area due to an extreme contingency. The new synchronous machine (SM) module of EMTP-RV enables the simulation of the machine from standstill and makes it possible to use it...
A high bandwidth critical path monitor (1 sample/ cycle at 4-5 GHz) capable of providing real-time timing margin information to a variable voltage/frequency scaling control loop is described. The critical path monitor tracks the critical path delay to within 1 FO2 inverter delay with a standard deviation less than 3 FO2 delays over process, voltage, temperature, and workload. The CPM is sensitive...
A circuit for on-chip measurement of long-term jitter, period jitter, and clock skew, is demonstrated. The circuit uses a single latch and a voltage-controlled delay element, and is evaluated in a stand-alone pad frame. Excellent reproduction of jitter measured by oscilloscope is shown. Measured jitter resolution is 1 ps or better. The circuit is also incorporated into a 2 GHz clock distribution network...
This study proposes a soft switched Output Current Sourcing (OCS) grid connected inverter that applies a high frequency isolation transformer. Current sourcing at the output implies that, ideally, the injected current will be independent on the load voltage. The current injected to the line is controlled by varying the switching frequency and dithering at low currents. The system does not require...
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