Passivity-Based Control of Switched Reluctance-Based Wind System Supplying Constant Power Load

Abstract

Abstract-This paper presents a passivity-based control (PBC) scheme for the Switched Reluctance Generator (SRG) in smallscale wind energy conversion systems (WECSs) for DC microgrid application. The main objective is to stabilize the output voltage in case the system supplies constant power loads (CPLs) and operates with maximum power point tracking (MPPT). Stability improvement and dc-link ripple reduction in the presence of CPLs is achieved using system level modeling of SRG-based DC microgrid through the Euler-Lagrange system (ELS) from the view point of the machine physical structure. Compared with other control methods, the proposed MPPT method based on passivity-based speed controller employs the back-EMF in the generation process as a position-dependent voltage source to overcome the major challenge of SRG complicated uncertain dynamic model. To deal with the time-varying inductance and back-emf of SRG, an adaptation mechanism is incorporated in proposed adaptive PBC and the control design is constructed by using the Lyapunov theorem where the closed-loop stability is ensured. The effectiveness of the proposed method in avoiding instability effects of SRG and CPL with voltage ripple reduction and precise wind turbine speed tracking is investigated with simulation results and validated with experimental by using a four-phase, 8/6 SRG drive system. Switched Reluctance Generator (SRG); Wind turbine; Passivity-based control; Constant-power load.

A novel nonlinear observer‐based LQ control system design for wind energy conversion systems with single measurement

“…Suppose that we need to track the optimal power for WCSs . In this study, we assume that Only ω is measurable; i d and i q (hence T e ) are unknown state variables. Wind speed v and aerodynamic torque T a are unknown and arbitrary. Because, the information of i d , T e , and T a are not available, the recent methods are failed to design a controller for tracking the optimal power. In addition, because the aerodynamic torque T a is arbitrary, therefore, it maybe does not fulfill the constraints, which make the proposed methods in these studies unable to apply for this case.…”

“…It is due to their endlessness and cleanness. In WECSs, wind speed is key information to be known in real time . Unfortunately, it is not easy to measure it with enough precision for control systems.…”

“…Several methods have been developed to obtain the information of wind speed in past few years. For example, the measurements with anemometers increase the cost as well as reduce the reliability of the overall systems . Another approach is to use the Kalman filters and gray models and genetic algorithms .…”

“…In WECSs, wind speed is key information to be known in real time. [1][2][3][4][5][6][7][8][9][10][11] Unfortunately, it is not easy to measure it with enough precision for control systems. Several methods have been developed to obtain the information of wind speed in past few years.…”

“…For example, the measurements with anemometers increase the cost as well as reduce the reliability of the overall systems. [3][4][5][6][7] Another approach is to use the Kalman filters and gray models 8,9 and genetic algorithms. 10 Although these methods can estimate wind speed with high accuracy, the methods are complicated, costly, and not easy to implement.…”