Modulación por Vector Espacial aplicada a un Filtro Activo de Potencia

Este documento presenta una metodología para reducir los armónicos generados por un rectificador trifásico no controlado, en el marco de la teoría de compensación del sistema de referencia síncrono dq0. Se ha utilizado la técnica de modulación de banda fija de histéresis junto con la modulación por vector espacial para controlar la corriente inyectada por el filtro. Los resultados obtenidos muestran una reducción en la distorsión de la corriente a un valor menor a 5 %

Modulación por Vector Espacial aplicada a un Filtro Activo de Potencia

Este documento presenta una metodología para reducir los armónicos generados por un rectificador trifásico no controlado, en el marco de la teoría de compensación del sistema de referencia síncrono dq0. Se ha utilizado la técnica de modulación de banda fija de histéresis junto con la modulación por vector espacial para controlar la corriente inyectada por el filtro. Los resultados obtenidos muestran una reducción en la distorsión de la corriente a un valor menor a 5 %

Modulación por Vector Espacial aplicada a un Filtro Activo de Potencia

Este documento presenta una metodología para reducir los armónicos generados por un rectificador trifásico no controlado, en el marco de la teoría de compensación del sistema de referencia síncrono dq0. Se ha utilizado la técnica de modulación de banda fija de histéresis junto con la modulación por vector espacial para controlar la corriente inyectada por el filtro. Los resultados obtenidos muestran una reducción en la distorsión de la corriente a un valor menor a 5 %

A comparative study of hysteresis band PWM techniques for current control in shunt active power filters

El presente artículo evalúa el desempeño de un filtro activo empleando tres diferentes técnicas de control de corriente de banda de histéresis: banda fija, banda adaptativa y con modulación por vector espacial. En la comparación se estudian las características de cada técnica y mediante simulación se evalúa su desempeño y operación. En todos los casos se emplea la teoría pq para el cálculo de las corrientes de referencia y se emplea un controlador proporcional para regular la tensión del bus de continua. De acuerdo con los resultados, las técnicas PWM evaluadas permiten una reducción del contenido armónico de la corriente de la red de alimentación de 31 % sin compensación, a un 6 %, considerando el filtro activo de potencia. La técnica de banda adaptativa de histéresis presenta el más bajo desempeño en la reducción de armónicos en las corrientes de la red. Además, se tiene que el método de banda fija de histéresis es el más recomendado para aplicaciones de filtros paralelo debido a que posee una estructura más simple que permite su implementación. Los resultados tambien muestran que la técnica de banda adaptativa de histéresis es la que presenta mayor reducción en las variaciones de la frecuencia de conmutación, requiriendo mayor número de operaciones, ya que requiere calcular el ancho de banda en cada iteración. Mientras que la técnica de modulación por vector espacial y banda de histéresis presenta frecuencias de conmutación altamente variables y mayor complejidad en su implementación.This paper evaluates the performance of an active power filter using three hysteresis band current control techniques: fixed-band, adaptive-band, and Space Vector Modulation. The characteristics of each method, along with their behaviour under different operating conditions, are studied by means of time domain simulations. The pq theory is used in all the cases to calculate the current reference, and a proportional controller is implemented to regulate the voltage in the dc bus. Based on the results, the PWM techniques evaluated in this work enable a reduction in the harmonic content of the supply grid currents that ranges from 31% without compensation to 6% after the active power filter is connected. The adaptive hysteresis band method exhibited the worst performance in the elimination of harmonics in grid currents; furthermore, it presented the largest reduction of variations in the switching frequency and requires more calculation time because the band width must be computed at each iteration. In turn, the fixed hysteresis band alternative is the most widely recommended for applications that involve parallel filters because it has a simpler structure that enables its implementation. Finally, the technique that combines space vector modulation and hysteresis band current control produced highly-variable switching frequencies and a more complex implementation

Mitigation of load harmonics from grid connected wind turbine using shunt active power filter

The increasing utilization of power electronics controlled devices in power system has increased distortion level in current and voltage waveforms in the form of harmonics. The increase in harmonic level also affects the performance of generator, thereby reducing its efficiency and lifespan. In this research, load harmonic mitigation method has been proposed for grid connected variable speed wind turbine generator using Shunt Active Power Filter (APF). The main advantage of this method is eliminating the effect of load harmonics from terminals of wind turbine generator and from the Point of Common Coupling (PCC). To evaluate the performance of shunt APF, two strategies have been utilized separately for extracting harmonic reference signal: the instantaneous reactive power method (pq method) and Synchronous Reference Frame (SRF) technique. To prove the effectiveness of the proposed system, MATLAB simulations have been carried out on 120 kV grid connected Permanent Magnet Synchronous Generator (PMSG) based wind turbine. Furthermore, nonlinear load is also attached to PCC under fixed and variable wind speed between 8 to 12 m/s separately. For proper operation of APF, switching pulses have been produced by hysteresis band current control. This technique decreases the magnitude of Total Harmonic Distortion (THD) to an acceptable limit set by IEEE-519 standard for harmonic control. Results have also shown that the shunt APF with SRF technique yields better performance under fixed and fluctuating wind speed compared to pq method

SVM based hysteresis current controller for a three phase active power filter

A space vector modulation (SVM) based hysteresis current controller (HCC) technique for a three phase shunt active power filter is proposed. The switching control algorithms of the proposed SVM based HCC manage to generate compensated current according to the reference current harmonics extraction is based on the instantaneous active and reactive power theorem in time domain by calculating the power compensation. A closed loop control system is implemented and the error current is the difference between the reference current obtained from the power compensation and the actual current that needs to be injected back into the line. By implementing this control strategy, the active power filter (APF) manages to generate better compensated harmonics currents to the line

SVM based hysteresis current controller for a three phase active power filter

A space vector modulation (SVM) based hysteresis current controller (HCC) technique for a three phase shunt active power filter is proposed. The proposed SVM based HCC is implemented in a closed loop control system. The reference input to the control system is the reference compensating harmonic current. The reference compensating harmonic current is obtained from the harmonic extraction tool or called as the harmonics isolator. The harmonics extraction is based on the instantaneous active and reactive power theorem in time domain to calculate the reactive power compensation in the power system. The error current is the difference between the reference and the actual compensating harmonic current from the power compensation. Three error currents are obtained and compared by using the hysteresis tolerance band comparators to obtain the information about the region and voltage vector. The switching control algorithms of the proposed SVM based HCC manages to generate appropriate switching gates to the active power filter. The active power filter generates the actual compensating harmonic current based on the switching gates provided by the controller. The actual compensating harmonic current is generated based on the reference compensating harmonic current. The actual compensating harmonic current is then injected back into the line to cancel the harmonic components in the distorted line. By implementing this control strategy, the active power filter (APF) manages to generate better compensated harmonics currents to the line. The proposed active power filter is able to improve about 67% of the total harmonic distortion (THD) for the distorted line current caused by an uncontrolled rectifier as the nonlinear loa

Design and implementation of a single phase active power filter

Various active filter solutions have been proposed in recent years {I], {2], and are still being widely investigated today. This thesis discusses the design and implementation of the shunt AP F topology

Planning and Management of a solar power-based distribution system

This thesis is aimed at the response of the power system network to the integration of solar photovoltaic (PV) generation and battery energy storage systems (BESS). Any solar power–based system integrated into a grid has voltage fluctuations that must be controlled through adaptive and robust control algorithms. The siting of battery in a distribution system affects system performance, including voltage regulation, system losses and cost minimization. In particular, here the aim is to analyse how the present-day schemes and technologies affect voltages, and their control, in the network. Another focus is on the optimal placement of BESS to facilitate system loss minimisation and cost reduction in the system. The battery placement optimisation is achieved through the minimisation of the losses in, and the cost of, the system. The voltage regulation is achieved through two control algorithms: Synchronous Reference Frame theory (SRFT) and adaptive linear neural network (ADALINE), which are subsequently modified by incorporation of fuzzy logic into the control system. Both battery placement optimisation and improvements to voltage regulation are shown to improve performance of the system. A further aim of this work is to improve cooperation between present day grid regulation equipment and schemes and the conventional methods through advancements in the control techniques. The aims of this thesis are as follows: 1. It is essential to place BESSs optimally. The aim of the thesis is to study and enhance the method of the optimal siting of battery energy storage in the presence of renewable energy–based power generating sources (RES)– such as solar PV – in a low-voltage power system network. A model for optimisation is developed to potentially find the battery site that enhances the hosting capability of the RES of the power system network. Among the essential points of this technique are its accuracy and robust nature. The fitness function includes the minimisation of the cost of operation and of system losses. 2. The second research objective is to examine the power control techniques of the inverter that might be leading to the voltage quality issues during unbalanced voltage scenarios, especially with solar PV–based generation in the power system. As such, after the implementation of the suggested coordination of the control mechanism into the grid under study, the variations in the voltage due to the solar PV variability dynamics are regulated more quickly and more precisely compared with the control schemes employed in the past. This substantially minimises the voltage fluctuations in time and amplitude, helps in mitigating hunting phenomena in voltage and provides alternative to the unnecessary control operations existing in the system