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Recent works have highlighted the growth of battery energy storage system (BESS) in the electrical system. In the scenario of high penetration level of renewable energy in the distributed generation, BESS plays a key role in the effort to combine a sustainable power supply with a reliable dispatched load. Several power converter topologies can be employed to connect BESS to the grid. There is no defined...
The insertion of grid connected photovoltaic (PV) in the power systems have occurred mainly at low and medium voltage. Besides, due to solar irradiance variation, these converters have excess capacity that can be used to provide ancillary services to the main grid. Therefore, this work is focused on the analysis of how PV inverters can perform ancillary services, supporting the grid. Control strategies...
The use of wind turbine as electricity source is growing globally and as consequence the grid codes are becoming more restrict. The restrictions depends on the country that the system is installed and basically limits the system disconnections during determined faults and demands the injection or absorption of active or reactive power during those faults to ensure a fast return of the system to its...
Photovoltaic energy has gained prominence in the current context of energy generation. The fundamental element of a photovoltaic system connected to the electric grid is the electronic converter. In order to be marketed, electronic converters must be tested and certified in accordance with current standards. In the certification process, an equipment known as a solar array simulator (SAS) is used...
Nowadays, the power systems are submitted to current and voltage harmonics due to the increased presence of nonlinear loads and the wide use of power inverters to interface solar and wind power plants. Nevertheless, these inverters can also be used to compensate the current harmonics. Traditional harmonic detection methods extracts all harmonic current information and the control tuning tends to be...
The main objective of a photovoltaic (PV) inverter is to inject the PV power into the ac-grid. Generally, due to variations in solar irradiance, inverters operate bellow their rated current. Therefore, this current margin can be used to ancillary services, such as harmonic current compensation. However, it is necessary to evaluate the effects of the harmonic current compensation in the efficiency...
The new generation of PV systems can have the capability to perform ancillary services in order to improve the power grid quality index. One of these services is the harmonic current compensation of nonlinear loads. An important issue to perform this service is the harmonic detection method. The traditional methods detects all harmonic contents of the load current and the control tuning tends to be...
As the wind energy generation becomes more frequently employed worldwide, specific grid codes concerning power quality are required for these systems. Several countries have determined that the wind turbines cannot be disconnected from the grid during voltage sags, depending on the severity of the sags. This has pushed manufacturers to implement low-voltage-ride-through strategies in their turbines...
The use permanent magnet synchronous generators (PMSG) in wind turbines has been increasing considerably due to its efficiency, low maintenance costs and reliability. PMSG's are connected to the grid by means of frequency converters. Generally a back-to-back full converter structure is preferred. This work intends to present system modeling and the application of interconnection and damping assignment...
The inverter multifunctional operation is based on the harmonic current compensation, generated by nonlinear loads. The traditional harmonic detection methods tracks all harmonic contents of the load current and the control tuning tends to be complex with low flexibility. In many works, the proportional resonant (PR) controllers are used to control the inverter current reference. However, one PR controller...
In the last few years, the number of grid connected wind conversion systems (WECS) has increased rapidly. One of the most commercialized WECS technologies is the doubly-fed induction generator (DFIG) that offers operational and economical advantages over other ones. Nevertheless, this system has as the main drawback the high susceptibility to grid disturbances. During unbalanced grid voltages, negative...
Photovoltaic (PV) systems have gained prominence in the context of distributed generation systems. The fundamental element of a PV grid-connected systems is the power converter. Before marketed power converters must be tested and certified according to the international standards. Therefore, a flexible equipment to test the converters is necessary. This paper presents the modeling and control structure...
The growing use of wind energy conversion systems around the world is pushing the individual power of wind turbines to higher values. Especially in offshore farms, where installation and maintenance have higher costs, high power wind turbines and their reliability become critical issues to make investments economically viable. In this context, multilevel converters, widely used in high power drive...
Single and three-phase photovoltaic inverters are essential components of the photovoltaic (PV) systems to extracting the PV power and injecting it into the grid. Thus, in order to extract the maximum power of the solar array for various solar irradiation tracks, it is used a maximum power point tracker (MPPT) algorithm. Due to variations in solar irradiance, inverters have a current margin, which...
This paper presents an inverter control scheme, based on proportional-resonant controllers, where the inverter works in multifunctional operation. In this case, the reactive power and harmonic compensation of the load are ancillary services. A resonant control is implemented in stationary reference frame (αβ), where is not necessary the use of a phase-locked loop (PLL). The instantaneous power theory...
In photovoltaic standalone systems it is crucial to absorb most of the available energy. Thus, in order to extract the maximum power of a solar panel for a given set of climatic conditions, it is used maximum power point tracker (MPPT). The MPPT consists in a power converter which controls the solar panel voltage. In this context, this work compares the instantaneous and dynamic efficiency of three...
Single and three-phase photovoltaic inverters are responsible to extract the photovoltaic array power and inject it into the grid. Due to variations in solar irradiance, inverters have a current margin, which is not explored during the day. Thereby, many works have proposed multifunctional operation. This concept consists in aggregate to the inverter control strategy other functions, such as harmonics...
The use permanent magnet synchronous generators (PMSG) in wind turbines has been increase considerably in offshore applications due to its efficiency, low maintenance costs and reliability. PMSG's are connected to the grid by means of frequency converters. Generally a back-to-back full converter structure is preferred. This work presents the application of interconnection and damping assignment passivity-based...
Photovoltaic (PV) systems have gained prominence in the current context of distributed generation systems. The fundamental element of a PV grid-connected systems is the power converter. Power converters must be tested and certified according to the international standards, before being commercialized. Therefore, a flexible equipment to test the converters is necessary. This paper presents the modeling...
Most of power transformers, before being commercialized, must undertake a series of tests with the objective of analyzing their operational behavior under real operating conditions. Such tests sometimes demand a high amount of power increasing significantly their costs. The paper presents a proposed system which allows testing in closed loop, reducing the energy consumption to the natural losses of...
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