Shailendra Sharma

Design and Implementation of Four-Leg Voltage-Source-Converter-Based VFC for Autonomous Wind Energy Conversion System

This paper deals with the design and implementation of a voltage and frequency controller (VFC) for a three-phase four-wire autonomous wind energy conversion system (WECS). The VFC is realized using a four-leg voltage source converter and a battery energy storage system. The enhanced phase-locked loop-based control algorithm is used in the VFC. A prototype of a 3.7-kW isolated asynchronous generator-based WECS is developed to demonstrate the performance of the VFC. The obtained test results have shown that the proposed VFC functions as a load leveler, a load balancer, a neutral current compensator, and a harmonic eliminator.

Performance of Voltage and Frequency Controller in Isolated Wind Power Generation for a Three-Phase Four-Wire System

This paper deals with a new control algorithm for a voltage and frequency controller (VFC) of an isolated wind energy conversion system (IWECS) using an isolated asynchronous generator to feed three-phase four-wire consumer loads. The reference source currents are estimated for the indirect current control of a voltage source converter (VSC) using the single-phase PQ theory to control the voltage and frequency of IWECS. A three-leg VSC with a battery energy storage system is used as a VFC for an IWECS. A nonisolated star-polygon transformer is used to provide a neutral terminal for four-wire loads and to compensate the neutral current resulting in reduction in rating of VSC. The proposed VFC is implemented using a DSP. Experimental results are presented to demonstrate the additional capabilities of VFC as a load leveler, a load balancer, a harmonic eliminator, and a neutral current compensator.

An enhanced phase locked loop technique for voltage and frequency control of stand-alone wind energy conversion system

This paper deals with the application of enhanced phase locked loop (EPLL) technique for the voltage and frequency controller (VFC) in a stand-alone wind energy conversion system (WECS) using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The fundamental component of three-phase load currents is extracted using EPLL. The EPLL is also used for estimation of the frequency of IAG. Three-leg voltage source converter (VSC) with a battery energy storage system (BESS) is used as a VFC for the stand-alone WECS. The star-hexagon transformer is used at point of common coupling (PCC) to realize the three-phase four-wire system. The EPLL based control algorithm is implemented using a digital signal processor. Test results are presented to demonstrate the capabilities of VFC as a load balancer, load leveler, harmonic eliminator and neutral current compensator.

Asynchronous generator with battery storage for standalone wind energy conversion system

This paper deals with the implementation of a voltage and frequency controller (VFC) for an isolated asynchronous generator (IAG) based stand-alone wind energy conversion system (SWECS) with a battery energy storage system (BESS) feeding three-phase four-wire loads. The control algorithm for VFC is based on a low pass filter (LPF) for estimation of reference source currents. The VFC is realized using a voltage source converter (VSC) with a BESS at its dc bus and a non-isolated T-connected transformer to feed three-phase four-wire consumer loads. Test results are presented to demonstrate the performance of a proposed VFC for an IAG in the wind power generation.

An autonomous wind energy conversion system with permanent magnet synchronous generator

This paper deals with a permanent magnet synchronous generator (PMSG) based variable speed autonomous wind energy conversion system (AWECS). Back-back connected voltage source converter (VSC) and a voltage source inverter (VSI) with a battery energy storage system (BESS) at the intermediate dc link are used to realize the voltage and frequency controller (VFC). The BESS is used for load leveling and to ensure the reliability of the supply to consumers connected at load bus under change in wind speed. The generator-side converter operated in vector control mode for achieving maximum power point tracking (MPPT) and to achieve unity power factor operation at PMSG terminals. The load-side converter is operated to regulate amplitude of the load voltage and frequency under change in load conditions. The three-phase four wire consumer loads are fed with a non-isolated star-delta transformer connected at the load bus to provide stable neutral terminal. The proposed AWECS is modeled, design and simulated using MATLAB R2007b simulink with its sim power system toolbox and discrete step solver.

Voltage and frequency control with reduced switch integrated voltage source converter for IAG in wind energy conversion system

This paper deals with a voltage and frequency controller (VFC) of a stand-alone wind energy conversion system using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Two-leg reduced switch integrated voltage source converter (VSC) with a battery energy storage system (BESS) is used as a VFC for the power management of the wind energy conversion system (WECS). The proposed VFC works as a voltage regulator, a load leveler, a load balancer and a harmonic eliminator in WECS. The wind power driven IAG system is modeled and simulated in the MATLAB using Simulink and sim power system (SPS) toolboxes.

SRF theory for voltage and frequency control of IAG based wind power generation

This paper deals with the control of voltage and frequency of an autonomous wind power generation based on isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The proposed control scheme is using the synchronous reference frame (SRF) theory based current detection. The proposed voltage and frequency controller (VFC) consists of a three leg voltage source converter (VSC) with a battery at its dc bus and a zig-zag transformer to provide a neutral terminal for three phase four wire loads. The mid-point of each leg of VSC is connected to three phase of incoming IAG supply through interfacing inductors. The proposed VFC is having bi-directional flow capability of active and reactive powers by virtue of that it regulates the system voltage and frequency. The VFC is capable of fulfilling the demand of reactive power of an asynchronous generator along with the function of load leveling, harmonic elimination, voltage regulation and load balancing. The complete generator system is modeled and simulated in the MATLAB using the Simulink and the sim power system (SPS) toolboxes. The simulated results are presented to demonstrate the capabilities of the proposed VFC for IAG in wind power generation.

Variable speed stand-alone wind energy conversion system using synchronous generator

This paper deals with a synchronous generator (SG) based variable speed stand-alone wind energy conversion system (WECS). The voltage and frequency controller (VFC) consists of two back-back connected voltage source converter (VSC) and voltage source inverter (VSI) along with a battery energy storage system (BESS) at intermediate DC bus to allow the generation at variable voltage and variable frequency. The load-side VSI is controlled to feed regulated voltage and frequency supply to consumers. The performance of the VFC is obtained under steady-state and dynamic conditions. The simulation results demonstrate that the VFC performs satisfactorily as load leveler, load balancer, a neutral current compensator and as a maximum power point tracker.

Isolated wind energy conversion with asynchronous generator for rural electrification

This paper deals with the implementation of a controller for an isolated wind energy conversion system (WECS) using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference source currents are computed using the power balance theory to control the voltage and frequency of WECS. Three-leg voltage source converter (VSC) with a battery energy storage system (BESS) is used as a voltage and frequency controller (VFC) for the isolated WECS. The star-delta transformer is used at point of common coupling to facilitate the three-phase four-wire load systems. Test results are presented to demonstrate the capabilities of VFC as a load leveler, load balancer, harmonic eliminator and neutral current compensator.

Power Balance Theory Based Voltage and Frequency Control for IAG in Wind Power Generation

This paper deals with an application of the power balance theory in a voltage and frequency controller (VFC) of an autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Three-leg voltage source converter (VSC) with a battery energy storage system (BESS) is used as a VFC for the power management of the wind energy conversion system (WECS). Bi-directional power flow capabilities of the proposed VFC in WECS are demonstrated through simulation results. The proposed VFC works as an IAG exciter, a voltage regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. The wind power driven IAG system is modeled and simulated in the MATLAB using the Simulink and the sim power system (SPS) toolboxes.