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In modern power systems and especially in autonomous distributed generation (DG), the frequency and voltage regulation should be continuously controlled. Hence the analysis of such a DG system is essential for the reliable operation of the local grid, with the voltage source inverter to play a key role as a controlled interface between the energy sources and the loads. In this frame, the complete...
This paper presents a locking-accelerated DPLL based on multi-output bang-bang phase detector (MOBBPD) with reused most significant bits (MSBs). The bang-bang structure has simple implementation by eliminating the sensitive time-to-digital converter (TDC), while MOBBPD allows for reduced loop locking-time due to the multi-output. To further accelerate the loop locking, a scheme of reusing the MSBs...
This paper presents a high resolution tunable ring oscillator type TDC (Time to Digital Converter). The proposed structure uses 2 ring oscillators composed of 8 differential inverters. Can be activated by selecting one of the three resolution in the structure, and can be selected in a ratio of 15/16, 13/32, 63/64, depending on fast and slow of the differential inverter delay. Also to increase the...
This paper proposes a bi-directional grid-tied converter with GPS capability for smart-grid applications. The novelty of this converter is that time-stamped grid voltage angle received via network communication channels has been used to synchronize the converter to the grid. Therefore, all grid-tied converters in a microgrid with this development will not require line voltage sensing and phase-locked...
The Modular Multilevel Converter (MMC) topology has a wide area of possible applications. Features like redundancy at the module level and fault current limiting capability makes it a robust solution for many power applications. Moreover, this topology is very useful as a test equipment for Power Hardware in-the-Loop simulations, especially as a DC grid simulator. This paper describes a recently commissioned...
The world is moving towards utilization of renewable energy generation systems from last few years. The implementation of micro-grids enables utilization of renewable sources and also helps in maintaining cleanliness of environment. Microgrid is nothing but grid consisting of energy generation sources and local load which can be operated in parallel with utility grids or can be operated in islanded...
A novel Jitter Cancellation Circuit (JCC) that reduces deterministic clock jitter induced by supply noise is designed. High Speed IO interface circuits require low deterministic clock jitter in order to meet the timing budget. Supply noise is a primary contributor of deterministic jitter. As data rates are scaling to higher frequencies, the acceptable jitter due to supply noise is decreasing. For...
Non-Line-Start Permanent Magnet Synchronous Machines (NLSPMSMs) have no damping windings in the rotor and hence cannot start themselves directly to the grid. For applications where a constant speed drive is preferred, NLSPMSMs are required to be driven by the grid. Therefore, inverter aided soft startup and soft stop of such kind of motors are necessary. In this paper, a modified method of switching...
A novel practical virtual synchronous generator control strategy considering the differences between inverters and real synchronous generators is proposed in this paper. The proposed control strategy improves the emulation method of damping power in swing equation, which does not need a PLL and in the meanwhile eliminates the effect on the droop coefficient caused by the traditional constant damping...
Solar storms can affect the terrestrial power grid by inducing potential differences between points on the earth. These can couple into the power system through earthed structures such as transformer earths, which in turn can result in transformer saturation through geomagnetically induced current (GIC). For systems such as voltage-source converter (VSC) HVDC, this causes a variety of problems. This...
This paper presents a linearized model of a line-commutated converter-based HVDC system based on mass-damping-spring concept. The model takes the characteristics of converters, controllers and DC transmission line into consideration and represents the dynamic behavior of LCC HVDC system in the low frequency range. The developed model not only can be easily used for stability analysis with some linear...
The ever growing penetration of Distributed Energy Resources (DERs), involving both conventional and renewable technologies, is changing the power system face. International Standards are being revised for including new requirements for DERs such as wider voltage amplitude and frequency protection thresholds and new local P=f and Q=V power regulation. This scenario has led to an increasing concern...
With the increases in demand of energy, the non renewable energy sources have depleted and also there is a concern of global warming with the use of non renewable source of energy. So there arises a need to find new energy resources which are in bulk and also does not affect the environment. Solar is one of the best solution among all the renewable source of energy available today. Nowadays photovoltaic...
With the rapid development of photovoltaic (PV) power generation, technology of the grid-connected photovoltaic system becomes an important part of the photovoltaic power generation. Based on this background, grid connection techniques of T-Type three-level grid-connected inverter with an LCL filter is studied in this paper. The subject combines SPWM modulation strategy and dual current loop control...
This paper presented Proportional Resonant (PR) current control of single phase grid connected inverter for PV energy conversion to the utility grid. The synchronization mechanism is Second-Order Generalized Integrator (SOGI) phase locked loop (PLL). The PR current control is regulator in stationary reference frame and an advantage is reduce current distortion. The implemented software using Real...
In this paper, the topology and the control scheme of the photovoltaic three-phase grid connected inverter based on voltage-oriented control (VOC) is analyzed. In VOC, a current control loop is used. The currents are controlled in a synchronous rotating dq-frame using a decoupled feedback control. The reference current of d-axis controller is extracted from instruction which comes from the former...
The paper presents topics about the connection of two single-phase inverters with different power capabilities connected in parallel to supply linear loads. The equations of difference related to control and modelling are programed in an embedded DSP 320TMS28F335 system. The model of synchronization of Phase Locked Loop (PLL), the measurement of active and reactive power and the selected control strategy...
The development in grid connected three phase inverter has increased the importance of achieving low distortion and high quality current waveform. This paper describes a method of reducing current ripple in a three phase grid connected inverter utilizing Proportional Resonance (PR) controller. The effectiveness of the PR current controller is demonstrated by comparing its performance with that of...
In this paper a dual band differential Digital-Controlled-Oscillator (DCO) with a reconfigurable delay cell in each four stages of digitally controlled ring Oscillator is proposed. The bands switching will done by a digital mode select bit. Each band will controls by 6 bit codes and varies in a 50MHz band width. Band variations occurs by changing the sizing of the current tails of Source-Coupled-Logic...
Increase in renewable power generation increases the power penetration to grid. Inverter plays a major role in power penetration. In this paper transformer-less single phase grid tie inverter based on synchronous reference frame current control is proposed to supply active power (P) to grid. This current control provides infinite control gain and zero steady state error ideally. The plant transfer...
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