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The increasing penetration of renewable energy sources in power systems has increased the amount of generating units employing power electronics as their grid interface, instead of synchronous generators. Their different dynamics have brought new challenges for power system operators; in particular, the reduction of the total inertia of power systems, which leads to larger frequency disturbances....
This paper presents a real-time, low-cost, wireless, AC and DC monitoring system based on an ATmega328P-PU microcontroller. The proposed system is composed by different client nodes, which have the task to measure the main electrical quantities involved in the system, and a server node that collects the data and send them to a display device. The system is well suited for a good accuracy monitoring...
In this paper, a variable dc bus control strategy is evaluated for a bidirectional grid connected electric vehicle (EV) charger topology. The EV charger under consideration comprises of an ac-dc 3-φ active rectifier stage followed by a dc-dc dual active bridge (DAB) converter. The voltage of the common dc-link between the ac-dc stage and the dc-dc stage is regulated such that it follows the voltage...
This paper addresses the stability challenges that exist in a bidirectional grid connected electric vehicle (EV) charger. The EV charger under consideration comprises of an ac-dc single phase active rectifier stage followed by a dc-dc dual active bridge (DAB) stage. small-signal models suited for stability analysis of this charger are derived. Controller design considerations are discussed in order...
The ease of expansion of power system and lowered cost made the use of modular converters in Renewable Energy System more common. Different configurations are implemented depending on the applications. Control strategies like fuzzy logic, droop method and charge control scheme are developed for achieving sharing of current and voltages among the converters. In this paper new modularization architecture...
This paper proposes the finite control set applied to the current control of an interleaved boost converter of photovoltaic systems. The proposed controller select the state of the converter semiconductor by using the predicted behavior of the converter and the minimization of a cost function. Hence, the controller guarantees that the current reference is reached. The current reference is computed...
In this article a sliding mode plus PI controller is proposed to control of the voltage and the input current of a photovoltaic system. The proposed nonlinear controller is designed to control the duty cycle of the two level interleaved boost converter due to changes in the operating conditions of the photovoltaic panel (changes in irradiance levels). Besides this, the proposed controller can operate...
Grid-connected doubly-fed induction generators suffer from limited fault ride-through capability during grid faults and disturbances. This paper proposes a control and energy management scheme for a DFIG-based wind energy conversion system with a converter-free battery energy storage that improves the quality of power delivered to the utility grid during normal operating conditions and enhances the...
This work presents a back to back converter topology with the ability to connect two power systems of different voltages and frequencies for the exchange of power. By utilizing indirect AC to AC conversion decoupling is achieved between the power systems with one of three phase, two level voltage source converters performing the AC to DC conversion that maintains the required DC bus voltage level...
The key drivers for Maximum Power Point Tracking (MPPT) solutions in photovoltaic (PV) power plants are independency from solar panels, fast tracking of irradiance and temperature variations, and efficiency of conversion capacity. In the most available MPPT solutions, some issues such as high implementation burden and performance degradation during abrupt changes have not been sufficiently investigated...
Maximum power point tracking (MPPT) is required to extract the maximum available power in PV systems. Wide variety of methods exist in literature, with range of complexity and effectiveness. The features of these diverse methods are usually evaluated at specific environmental conditions for a tiny period, and then the evaluations are generalized for PV systems working under long-term environmental...
Using renewable sources to meet the load demand in the distribution level has become more economical and prevalent. The integration of these sources has impact on the load flow direction and magnitude. These changes can affect the operation of overcurrent (OC) relays as the main protective device in medium voltage (MV) distribution networks. In other words, the changes in the current magnitude and...
Multi modular converter (MMC) based DC to AC converters are widely used to interface large rating renewable energy power plants to electric grid. The performance of these converters depends on the pulse width modulation (PWM) algorithm used. This paper proposes an improved space vector PWM (SVPWM) algorithm for MMC which ensures voltage balance across each sub module and also results in low circulating...
This paper presents a new structure of a power sharing controller for a modular based dual active bridge (DAB) DC/DC converter. The modular topology is based on input-series output-parallel (ISOP) connection of DAB modules suitable for a voltage step down application at medium voltage level. Since DAB has bi-directional power flow capability, this connection would act as its dual input-parallel output-series...
With the steady transition towards a more dominant decentralized power generation and the further reduction of conventional fossil fuel-based power plants, future utility grids require higher demands regarding voltage quality and supply reliability. Active power filters with energy storage capability, here referred to as Power Conditioning Systems (PCS), offer grid supporting and stabilizing measures...
This paper illustrates the implementation and the study of a hybrid electric power system based on a 10kW-diesel generator associated to renewable energy sources including a 10kW wind turbine, 12kW photovoltaic, and 53Ah lithium-battery. These energy production sources are interfaced to micro-grid through three-level power electronics converters where the phase-to-phase RMS voltage is 600V. The variable...
Increasing environmental pollutions, lack of power in remote places and demand for more energy makes us to seek new energy sources. Wind and solar hybrid energy have being popular ones owing to abundant, complement nature, ease of availability and convertibility to the electric energy. For hybridizing solar-wind system DC-AC or separate DC-DC converters are used one for each source. They will be connected...
This study developed a methodology to determine zones of acceptable voltage profiles for wind power generation connected to distribution systems. Three load profiles (residential, commercial and industrial) connected to the distribution network were analyzed considering the impact on voltage levels and steady-state stability for different wind speeds and wind generator control strategies. The wind...
The role of inertia emulation and voltage control is fundamental to support the integration of distributed generation in weak power grids and Virtual Synchronous Machines (VSMs) represent an attractive solution to assume both of these roles. However, VSMs act as voltage sources and this makes it difficult to address power quality issues. Virtual impedances are commonly applied in the literature to...
In this paper, a four-port DC-DC converter(FPC) is proposed for electric vehicle application integrated with renewable sources and energy storage system. The four port of the converter is two input, one bidirectional port, and one output. The charging, discharging states and the disturbance at the input side are controlled. The detailed analysis and simulation of the four-port DC-DC converter are...
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