PEDDA SURESH
@hitam.org
Professor
Hyderabad Institute of Technology and Management
RESEARCH, TEACHING, or OTHER INTERESTS
Multidisciplinary, Multidisciplinary, Electrical and Electronic Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Bidyadhar Subudhi and Pedda Suresh Ogeti
Institution of Engineering and Technology (IET)
In this study, a new optimal preview control (OPC) is proposed for stator active and reactive power controls of a doubly fed induction generator (DFIG) wind energy conversion system (WECS). These powers are controlled by rotor currents to avoid the stator active and reactive power pulsations. This OP controller is designed based on linear quadratic regulator (LQR) approach. In view of efficient superior tracking and disturbance rejection ability, OPC is chosen to control active and reactive powers of WECS. The proposed OPC is designed in order to minimise the error due to cross-coupling-induced electromotive force (emf) and emf-induced due to stator flux using feedforward compensation loops. This controller is developed for both sub-synchronous and super-synchronous modes of DFIG with stator voltage-oriented control (SVOC). An augmented error system is derived for tracking the desired response (active and reactive power controls) of DFIG WECS. Then, the constraints in error state equation are minimised by selecting quadratic performance index in which weighing factors are used for achieving faster rotor current control dynamics. Finally, pulse width modulation switching scheme for voltage-source converters has been designed with outputs of rotor current control loop dynamics. Extensive simulations are conducted using MATLAB/Simulink and then experiments are carried out using OPAL-RT and hardware set-up developed in the laboratory for DFIG WECS for validating the efficacy of the proposed control algorithm. The performances of the proposed LQR-OPC are compared with that of sliding mode field-oriented control (SM-FOC) and direct torque control (SM-DTC). From the comparison, it is observed that the LQR-OPC algorithm with SVOC technique applied to DFIG WECS provides excellent steady-state stability and zero steady-state error in face of transient disturbances both on rotor side and grid side compared with traditional FOC and DTC methods.
Bidyadhar Subudhi and Pedda Suresh Ogeti
IEEE
Wind energy, is a variable source which requires a robust controller to achieve good pitch and torque control performance. A sliding mode control(SMC) strategy is proposed to ensure stability by using Torque and Pitch control despite of model uncertainties in Double fed induction generator (DFIG) for wind energy conversion system. This technique was implemented in MATLAB SIMULINK and Field Programmable Gate Arrays (FPGA). The generator-side converter (rectifier) is used to control the speed or torque of the generator with maximum power point tracking (MPPT) scheme. The grid-side converter (inverter) is employed for the control of DC link voltage and grid-side reactor power. Performance of the SMC has been compared with Hill Climbing (HC) algorithm and Perturb and Observe (P&O) algorithm. Finally the results obtained in MATLAB SIMULINK are implemented in FPGA. Both simulation and validation results show that the proposed control strategy is effective in terms of power regulation. Moreover, the sliding mode approach is arranged so as to produce no chattering in the generated torque that could lead to increased mechanical stress because of strong torque variations.
Bidyadhar Subudhi and Pedda Suresh Ogeti
Polish Academy of Sciences Chancellery
Abstract Wind energy, being a fluctuating resource, requires a tight control management to ensure stability when integrated with the grid system. This has triggered interest towards developing advanced controllers. Hence this paper presents the study of a variable speed wind energy conversion system that uses a Double Fed Induction Generator (DFIG). Above rated wind speed, pitch control has been applied and below the rated speed torque control has been adopted. Generator torque control is able to reduce the effects of the pitch actuator limitations. Sliding mode control is applied for torque and pitch control in WECS and it has been implemented in MATLAB SIMULINK and FPGA to achieve control of active and reactive power exchange between the stator of the DFIG and the grid. Performance parameters like pitch angle, active, reactive power, turbine speed, and DC voltage has been compared by using SMC, Hill Climbing (HC) Algorithm and Perturb and Observe (P&O) Algorithm and performance for these three methods has been simulated and implemented in FPGA. Total Harmonic Distortion for all the performance parameters has been reported. Hardware implementation of developed algorithm was accomplished with the help of Xilinx system generator and Xilinx Tool Kit.