scholarly journals Discrete-Time Nonlinear Control of VSC-HVDC System

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
TianTian Qian ◽  
ShiHong Miao
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Discrete Time ◽  
Time Domain ◽  
Output Feedback ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Mimo System ◽  
Discrete Control ◽  
Hvdc System

Because VSC-HVDC is a kind of strong nonlinear, coupling, and multi-input multioutput (MIMO) system, its control problem is always attracting much attention from scholars. And a lot of papers have done research on its control strategy in the continuous-time domain. But the control system is implemented through the computer discrete sampling in practical engineering. It is necessary to study the mathematical model and control algorithm in the discrete-time domain. The discrete mathematical model based on output feedback linearization and discrete sliding mode control algorithm is proposed in this paper. And to ensure the effectiveness of the control system in the quasi sliding mode state, the fast output sampling method is used in the output feedback. The results from simulation experiment in MATLAB/SIMULINK prove that the proposed discrete control algorithm can make the VSC-HVDC system have good static, dynamic, and robust characteristics in discrete-time domain.

scholarly journals Discrete–Time Integral Sliding Mode Control with Disturbances Compensation and Reduced Chattering for Pv Grid–Connected Inverter

2015 ◽  
Vol 66 (2) ◽  
pp. 61-69 ◽  
Author(s):  
Santolo Meo ◽  
Vincenzo Sorrentino
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Integral Sliding Mode Control ◽  
Integral Sliding Mode ◽  
Mode Control ◽  
Time Integral ◽  
Grid Connected Inverter ◽  
Disturbances Compensation

Abstract In the paper a new discrete-time integral sliding mode control (DISMC) with disturbances compensation and reduced chattering for grid-connected inverter is proposed for active and reactive power regulation. Differently by many SMC proposed in literature that have a time-continuous formulation in spite have been implemented with digital processor, the proposed DISMC is fully formulated in discrete-time, taking into account the effects introduced by a microprocessor-based implementation. As will be demonstrated such approach consents to reduce the chattering about the sliding manifold within a boundary layer of O(T2) thickness instead of O(T) (being T the sampling period of the control algorithm). Moreover it introduces a correction of the control vector which eliminates the influence of modeling error and external disturbances improving stability and robustness of the controlled system. Constant converter switching frequency is achieved by using space vector modulation, which eases the design of the ac harmonic filter. In the paper, after a detailed formalization of the proposed control algorithm, several numerical and experimental results on a three-phase grid-connected inverter prototype are shown, proving the effectiveness of the control strategy.

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