Jitendra Solanki

A Comparison of Control Algorithms for DSTATCOM

In this paper, a Distribution STATic COMpensator (DSTATCOM) is proposed for compensation of reactive power and unbalance caused by various loads in distribution system. An evaluation of three different methods is made to derive reference currents for a DSTATCOM. These methods are an instantaneous reactive power theory, a synchronous reference frame theory, and a new Adaline-based algorithm. The Adaline-based algorithm is an adaptive method for extracting reference current signals. These schemes are simulated under MATLAB environment using SIMULINK and PSB toolboxes. Simulation and experimental results demonstrate the performance of these schemes for the control of DSTATCOM.

Neural Network-Based Selective Compensation of Current Quality Problems in Distribution System

Active power filters (APFs) have been used to compensate harmonics, reactive current, and negative sequence fundamental frequency current drawn by nonlinear loads. The control of APF is the core issue for their proper operation. The flexibility of selective compensation embedded in the control scheme makes APF versatile for compensation of reactive power, harmonic currents, and unbalance in source currents and their combinations, depending upon the limited rating of voltage source inverter employed as APF. The proposed scheme utilizes neural network-based decomposition of the load current into positive and negative sequence fundamental frequency component, reactive component and harmonic components. The adaline-based current decomposer estimates the reference currents through tracking of unit vectors together with tuning of the weights. The implementation of the control scheme facilitates selective compensation which respects the limited rating of the APF. The simulated results using developed MATLAB model are presented and are validated by experimental results to depict the effectiveness of the proposed control method of APF

An Implementation of an Adaptive Control Algorithm for a Three-Phase Shunt Active Filter

This paper deals with the hardware implementation of a shunt active filter (SAF) for compensation of reactive power, unbalanced loading, and harmonic currents. SAF is controlled using an adaptive-linear-element (Adaline)-based current estimator to maintain sinusoidal and unity-power-factor source currents. Three-phase load currents are sensed, and using least mean square (LMS) algorithm-based Adaline, online calculation of weights is performed and these weights are multiplied by the unit vector templates, which give the fundamental-frequency real component of load currents. The dc bus voltage of voltage source converter (VSC) working as a SAF is maintained at constant value using a proportional-integral controller. The switching of VSC is performed using hysteresis-based pulsewidth-modulation indirect-current-control scheme, which controls the source currents to follow the derived reference source currents. The practical implementation of the SAF is realized using dSPACE DS1104 R&D controller having TMS320F240 as a slave DSP. The MATLAB-based simulation results and implementation results are presented to demonstrate the effectiveness of the SAF with Adaline-based control for load compensation.

Load Compensation for Diesel Generator-Based Isolated Generation System Employing DSTATCOM

This paper presents the control of distribution static synchronous compensator (DSTATCOM) for reactive power, harmonics and unbalanced load current compensation of a diesel generator set for an isolated system. The control of DSTATCOM is achieved using least mean square-based adaptive linear element (Adaline). An Adaline is used to extract balanced positive-sequence real fundamental frequency component of the load current and a proportional-integral (PI) controller is used to maintain a constant voltage at the dc-bus of a voltage-source converter (VSC) working as a DSTATCOM. Switching of VSC is achieved by controlling source currents to follow reference currents using hysteresis-based PWM control. This scheme is simulated under MATLAB environment using Simulink and PSB block-set toolboxes for feeding linear and nonlinear loads. The modeling is performed for a three-phase, three-wire star-connected synchronous generator coupled to a diesel engine, along with the three-leg VSC working as a DSTATCOM. Results are presented to verify the effectiveness of the control of DSTATCOM for the load compensation and an optimal operation of the DG set.

A Comparative Study of Control Algorithms for DSTATCOM for Load Compensation

DSTATCOM (distribution STATic COMpensator) is used for compensation of reactive power and unbalance caused by various loads in distribution system. This paper evaluates three different methods of determining the compensating current for a DSTATCOM. The methods compared, are the instantaneous reactive power theory, synchronous reference frame theory and a new Adaline based algorithm. The Adaline based algorithm is an adaptive method for extracting reference current signals. These three schemes are simulated under MATLAB environment using SIMULINK and PSB toolboxes. Simulation results depict the performance of these schemes for control of DSTATCOM.

Neural Network Based Control of Reduced Rating DSTATCOM

This paper presents a DSTATCOM controlled by a neural network based reference current extractor (NNREC) and rating reduction by use of shunt connected capacitor bank for three-phase three-wire system. The working of DSTATCOM with self supported dc bus is used in two different modes; one is, unity power factor (UPF) mode and second is, zero voltage regulation (ZVR) mode. The heart of the control of DSTATCOM is the derivation of reference currents, which decide the switching of three legs of voltage source inverter (VSI) used in DSTATCOM. The NNRCE is used for control of DSTATCOM, which operates on LMS algorithm. The real positive sequence current component of current is extracted using NNRCE without any phase shift. A PI controller is used to regulate the voltage across the capacitor connected at the dc bus of the VSI. In the ac voltage regulation mode, second PI controller is used to maintain the constant voltage at PCC with variation of load. To reduce the rating of DSTATCOM, an ac capacitor bank of almost half rating of the VAR required is connected at the load end. The simulations are carried out in MATLAB environment for unity power factor operation and ac voltage regulation through leading power factor operation. Simulation results verify the effectiveness of the DSTATCOM system to meet the requirements of distribution system

Load Compensation for Diesel Generator Based Isolated Generation System Employing DSTATCOM

This paper presents the control of distribution static compensator (DSTATCOM) for reactive power, harmonics and unbalanced load currents compensation on diesel generator (DG) set for isolated system. The control of DSTATCOM is achieved using least mean square (LMS) based Adaline. The Adaline is used to extract the balanced positive sequence real fundamental frequency component of load current and PI (proportional integral) controller is used to maintain the constant voltage at the dc bus of voltage source converter (VSC) working as DSTATCOM. Switching of VSC is achieved by controlling source currents to follow reference currents using hysteresis based PWM control. The scheme is simulated under MATLAB environment using Simulink and PSB block-set toolboxes for linear and nonlinear loads. The modeling is performed for 3-phase, 3-wire star connected synchronous generator coupled to diesel engine, along with the 3-leg VSC working as DSTATCOM. The results verify the effectiveness of the control of DSTATCOM for load compensation and optimal operation of DG set.

A Solid State Compensator with Energy Storage for Isolated Diesel Generator Set

This paper presents the control of battery energy storage system (BESS) with diesel generator (DG) set. The performance of the DG set is observed best when operated at full load or near full load (up to 80-100% load) condition. For this purpose a BESS is employed which ensures the load on the generator remains in between 80% to 100% of full load. Under light load condition (load less than 80%) the battery is being charged and in heavy load condition (load more than 100%) energy from battery is utilized to feed extra power to the load and when load is in-between 80 to 100% battery remain in floating condition. Along with load management, BESS provides the reactive power, harmonic current and unbalanced load current compensation. The control of BESS is achieved using synchronous reference frame theory (SRF) to extract the balance positive sequence real fundamental frequency component of load current. The switching of voltage source converter (VSC) working as BESS is achieved by forcing source currents to follow reference currents using hysteresis based PWM controller. The complete system is simulated under MATLAB environment using SIMULINK and PSB block-sets to demonstrate the capabilities of the system

Neural Network Based Control of DSTATCOM with Rating Reduction for Three-Phase Four-Wire System

Electrical distribution system suffers from problems like reactive power burden, unbalance loading and voltage regulation. Reactive power burden increases line losses and unbalance loading results in excessive neutral current. The use of distribution static synchronous compensator (DSTATCOM) is well established to cater these problems. Two core issues with the use of DSTATCOM are its control and rating. The heart of the control of DSTATCOM is the derivation of reference currents, which decide the switching of voltage source inverter (VSI) used in DSTATCOM. This paper deals with neural network based reference current extractor which operates on LMS algorithm. The neural network is used to extract the real positive sequence current component of load current. To compensate the neutral current, a four leg topology of VSI is used with the dc bus capacitor. The dc voltage across this capacitor is maintained constant using a PI controller. Similarly, in ac voltage regulation mode another PI controller is used to maintain the constant voltage at PCC with variation of load. To reduce the rating of DSTATCOM, a capacitor bank of rating of half the VAR required is connected at the load end. The simulations are carried out in MATLAB environment for unity power factor operation and voltage regulation through leading power factor operation. Simulation results verify the effectiveness of the DSTATCOM system to meet the requirements.

Adaline based control of battery energy storage system for diesel generator set

This paper presents the operation of battery energy storage system (BESS) with diesel generator (DG) set. The performance of the DG set is observed best when operated at full load or near full load (up to 70-80% load) condition. For this purpose a BESS is employed which ensures the load on the generator remains in between 80% to 100% of full load. Under light load condition (load less than 80%) the battery is being charged and in heavy load condition (load more than 100%) energy from battery is also utilized to feed extra power to the load. Along with load management, BESS provides the reactive power, harmonic and unbalanced load current compensation. The control of BESS is achieved using least mean square (LMS) based Adaline. The Adaline is used to extract the balance positive sequence real fundamental frequency component of load current. The switching of voltage source converter (VSC) working as BESS is achieved by forcing source currents to follow reference currents using hysteresis based PWM control. The scheme is simulated under MATLAB environment using SIMULINK and PSB block-sets. The modeling is performed for 3-phase 4-wire star connected synchronous generator, along with the 4-leg VSC working as BESS. The results verify the effectiveness of the Adaline based control of BESS to meet load compensation and optimal operation of DG set