This paper proposes a finite time control for a class of linear time invariant multi-input continuous-time (CT) and discrete-time (DT) controllable systems. The main idea is to reduce the system order to zero, by using higher sliding control which drives states to origin in finite time. The control scheme is fully decentralized and differentiators are not needed for control realization. The CT reaching control uses the quasi-continuous control. For DT systems a new type of order reducing control named multi-step equivalent control is proposed. This control annihilates both the switching functions and states in a finite number of discrete time units, resulting in a dead-beat control.

A new design of a digital control system for the grid-connected doubly fed induction generator is described in this paper. A discrete-time state-space model of the controlled system is obtained in the stator stationary reference frame. Using this model, a discrete-time sliding mode based control system is designed. Its tasks are the grid synchronization and the direct power control. The discrete-time equivalent control method is applied, and the control vector is calculated from the samples of voltages and currents. The control vector is converted to a switching sequence in a power converter using the space vector modulation. The modulation period is equal to the sampling period. A disturbance compensator is designed to eliminate the influence of the discretization effect and model uncertainties. In this way, a robust control system with a constant switching frequency is designed. Its digital hardware implementation is simple. The performance of the designed control system is tested on a simulation model.

This paper presents a design of a direct power control using the discrete-time sliding mode control. The design is intended for a grid-connected inverter or a doubly fed induction generator. The constant switching frequency is implemented by the space vector modulation, having the modulation period equal to the sample period. The effects of the discretization and external disturbances are analyzed. To solve this problem, a power based disturbance compensator is proposed. Its digital hardware implementation is simple. The simulation results show that the designed control system has a better steady state performance and robustness than a non-compensated control system.

This paper considers a hybrid approach to control of linear dynamic and impulse controllable continuous-time disturbed linear descriptor systems. The first step in control is a design of continuous state feedback that makes system impulse-free. The obtained system is represented as a state space system of relative order zero. Based on this model, a full order discrete-time sliding mode control providing given pole placement is designed. The reaching control is completely decentralized and chattering-free. Simulations show a very good suppression of slow disturbances. All design steps and simulations require only standard MATLAB Toolbox.

This paper presents a design of a digital direct power control strategy for a three-phase grid-connected inverter combining the discrete-time sliding mode control and the space vector modulation. Using the discrete-time state-space model of the controlled system, a discrete-time sliding mode control system is designed. Its output is a control vector which minimizes the instantaneous active and reactive power displacement from their reference values. The control vector is computed from the samples of voltages and currents and then converted to a switching sequence using space vector modulation. The period of modulated signal is equal to the sample period. A correction of the control vector is defined with aim to eliminate the influence of the system uncertainties using predicted values of the active and reactive powers. In this way a robust control system with a constant switching frequency is designed. Its digital hardware implementation is very simple. This control system is tested on a simulation model and compared with other similar approaches.

This paper proposes a new closed loop frequency based method for a parametric identification of some types of Wiener-type nonlinear plants. It provides a parametric model of the linear part of the plant, and a point by point relationship between input and output of the nonlinear part of the plant. Two approaches are proposed for the identification of the nonlinear part. The first approach is slower, but it does not require any additional equipment expect the relay. The second approach is much faster, but it requires some additional equipment.

This paper presents a novel Direct Power Control strategy for a three-phase grid connected multilevel inverter. The proposed DPC strategy combines discrete-time sliding mode control and predictive control. The active and reactive power are directly controlled by inverter switching states, represented by a switching vector, using the value of the power error computed from samples of phase voltages and currents. An appropriate switching vector is selected for each sampling period to minimize average value of the switching functions on the time interval on three sampling periods. The prediction of phase voltages and currents is necessary for algorithm implementation. The switching frequency is constant, and the digital control implementation is simple. The designed control system is tested using a simulation model of a three-level neutral-point clamped multilevel inverter. Simulation results confirm the design aims.

This work presents a new approach to high performance velocity servo system design. The approach is based on a discrete-time sliding mode (DSM) control with disturbance compensation. For the purpose of design, the controlled plant is approximated by first-order model. The traditional, as well as the integral type of DSM control is considered. The disturbance compensator is based on the fact that the matched disturbances are directly reflected in the previous value of the switching function. In this paper, slow varying disturbances are estimated by a parallel connection of first- and second-order estimators. The integral type of DSM velocity servo system with such combined compensator can track references and significantly reject bounded disturbances, both up to cubic parabola type. The proposed control system is chattering-free. Theoretically obtained results are verified by simulations and experiments.

The topic of this paper is modeling of wireless ad hoc networks in order to obtain the mathematical expressions for the maximum clique size and the node degree distribution function. Two types of the node distribution are considered: a uniform distribution of the Cartesian coordinates and a uniform distribution of the polar coordinates. The focus here is on the one-hop neighborhood of the specific node. The nodes of network are in a disk having its radius equal to the transmission range of the nodes. This approach highly simplifies calculation of the link probabilities in a network. The simulation results indicate an acceptable accuracy of the proposed mathematical expressions even in a widely used random geometric graph model of the network in the rectangle area.

This paper presents an approach to Direct Power Control (DPC) of a three-phase grid connected three level neutral-point clamped inverter. The presented approach can be extended to other topologies of multilevel inverters. The proposed DPC strategy is based on the Sliding Mode Control (SMC). The active and reactive power are directly controlled by three-level inverter switching states using the value of the delivered power error calculated from previous samples of three phase voltages and currents. An optimal control vector defined in dq reference frame minimizing the ripple is obtained using predicted values of three phase currents. An appropriate switching sequence is generated for each optimal vector using direct and indirect way. In the direct way the switching vector the nearest to the optimal control vector, and the direct way uses space vector modulation. The proposed strategy is robust to system parameters variations. The major advantage of proposed approach is its simple analog/digital control implementation. Moreover, PID controllers, look-up tables, and pulse-width modulators are not necessary. The designed control system is tested on a simulation model of a three-level neutral-point clamped multilevel inverter. Simulation results of a three-level neutral-point clamped multilevel inverter topology confirm the design aims.

This paper considers design in state space of reduced and integral sliding mode having either desired spectrum or optimal behavior in LQR sense. Due to the operator representation of system equation a separate consideration of discrete time and continuous time is not needed. The obtained sliding subspace enables a fully decentralized design of reaching control. Four very simple algorithms are the paper's outcome. Examples of their implementation in MATLAB are given at the end.

Unit disk graphs (UDG) are a natural choice for wireless network modeling. However, complex UDG algorithms with a long processing time could be ineffective because of nodes mobility and the lack of processing power of the nodes. Therefore, they should be adapted for use in wireless networks. In this paper we present an accelerated algorithm for maximum clique in UDG using simple calculations. The input of the algorithm is an ordered set of graph edges. Our approach is to decrease the number of edges involved in algorithm, and then to reorder the edges for faster processing. The ordering criterion uses two-hop neighborhood information. The simulation results show a significant shortening of algorithm processing time. Two types of node distribution, x-y and p-ϕ were tested. The results depend on the distribution type. This indicates a possibility to create adaptive algorithms fitted to a specific type of node distribution in the network.

This paper proposes a new approach for slow and matched disturbance suppression in digital sliding mode. The previous value of disturbance is extracted from switching function and used to make disturbance estimation, and later used in control to cancel disturbance effects. The control function is linear in state and in disturbance estimate. It may be considered chattering free since its value is zero in equilibrium if there are no disturbances.