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This paper proposes safety function in control laws to reduce the frequency of events that a physical value in a control system deviates from its normal operating-range. This safety function is realized mainly by the safety ability to suppress the fluctuations of transient responses after a device failure in order to prevent the deviations from the normal operating-range on the basis of dependability...
The controller for plants with dynamics asymmetry caused by the actuator rate saturation change has been suggested and analyzed. The control algorithm used in the proposed controller is modification of the PI control method. The characteristic property of the algorithm is that the value of integral constant of the controller is changed when the sign of the plant output parameter time derivative changes...
Arc grounding over-voltage is one of the worst over-voltages in the neutral isolated system. It is an important factor to be considered when selecting neutral ground mode. At present, system simulation is the main method for the study of the arc grounding over-voltage. Arc extinguish and re-ignition is simulated by controlling the switch on or off. However, the switch opening or closing need to be...
In this paper, a microgrid architecture comprised of parallel inverters, critical loads, and CAN communication is studied. The controller designs in both grid-tie and islanding modes for the designed MG system are described. How to distribute the currents among paralleled inverters with CAN bus as communication interface is addressed. The mode transfer tests are conducted with an inverter-simulated...
To overcome the drawbacks of the conventional gate drive, in this paper a closed-loop gate control method is proposed. In this novel method, the switching speed, specifically di/dt, is measured from the voltage across the parasitic inductance of the IGBT module and a closed-loop control is employed to adaptively adjust the gate drive voltage to control the switching speed according to a preset control...
A linear-to-nonlinear translator is proposed herein and applied to the boost converter to improve the operating performance of the boost converter all over the input voltage range. The proposed translator is inserted between the PID controller and the main power stage such that the PID controller considers the behavior of the boost converter to be quasi-linear, thereby suppressing the effect of nonlinear...
In order to adhere to voltage regulation criteria, capacitor selection of a Buck converter must be based on the worst possible scenario. It is well known that, for a low duty cycle Buck converter, the output voltage deviation of a Buck converter undergoing an unloading transient will be significantly larger than that of a corresponding loading transient of equal magnitude. Therefore, in this paper,...
With the advent of battery-powered portable devices and the mandatory adoptions of power factor correction (PFC), non-inverting buck-boost converter is attracting numerous attentions. Conventional two-switch or four-switch non-inverting buck-boost converters choose their operation modes by measuring input and output voltage magnitudes. This can cause higher output voltage transients when input and...
Run-time reconfiguration of digital signal processing systems is common in today's complex, non-linear and/or time-variant, distributed signal processing and control solutions. Reconfiguration transients caused by the run-time configuration change degrade the quality of service provided by solution, and they may also cause failures in the system. The paper investigates the transient properties of...
The voltage mode control (VMC) technique of switchmode converters has been widely used in renewable PV system applications. The feasibility of the current mode control (CMC) techniques in PV applications is also promising because of the irregular nature of the PV source. This paper presents a comparative assessment of the VMC and four different CMCs of switch-mode converters for photovoltaic (PV)...
Smart building technologies are being developed in order to optimize energy usage in residential and commercial facilities electrical systems. One aspect of computer network based control systems is the intrinsic time-delays present in communicating feedback signals. This creates reduced stability margins in variable speed drives used for heating, cooling, ventilation and refrigeration systems. This...
The load disturbance rejection problem is analyzed. The Proportional - Integral - Derivative (PID) controller with the switched parameters based on a control algorithm, which is a modification of the conventional PID control method, has been suggested. The principal characteristic feature of the PID controller with the switched parameters is that different values of the proportional, integral and...
Digital adaptive voltage positioning (AVP) techniques with fast transient response for voltage regulator modules (VRMs) are proposed in this paper. An AVP control unit is used to achieve AVP, by generating dynamic voltage reference and dynamic current reference. Two digital-to-analog converters therefore can be used instead of analog-to-digital converters to reduce system complexity. A straightforward...
Controlled switching taking into account the residual flux can - in theory - completely eliminate transient transformer inrush currents. Real factors such as closing time scatter of the circuit breaker and uncertainty in the residual flux measurement significantly reduce its performance in the field. To quantify the acceptable tolerances of these factors if no inrush currents have to occur, a systematic...
The closed-loop control system structure, in which the controller is provided with the information that allows the controller to know if the control system was disturbed by the set point change or not and enables it to operate with different parameters during the set point change response and the load disturbance response, has been presented. The proposed control system structure with the set point...
Polymorphic gates can be considered as a new reconfigurable technology capable of integrating logic functions with sensing in a single compact structure. Polymorphic gates whose logic function can be controlled by the level of the power supply voltage (Vdd) represent a special class of polymorphic gates. A new polymorphic NAND/NOR gate controlled by Vdd is presented. This gate was fabricated and utilized...
Networks on chips (NoCs) provide a mechanism for handling complex communications in the next generation of integrated circuits. At the same time, lower yield in nano-technology, makes self repair communication channels a necessity in design of digital systems. This paper proposes a reliable NoC architecture based on specific application mapped onto an NoC. This architecture is capable of recovering...
In this paper we propose a set of different configurations of failure recovery schemes, developed for network-on-chip (NoC) based systems. These configurations exploit the fact that communication in NoCs tends to be partitioned and eventually localized. The failure recovery approach is based on checkpoint and rollback and is aimed towards fast recovery from system or application level failures. The...
With the development of the communication technology, computer networks present characteristics of scale, heterogeneous and dynamic. Traditional TCP has been designed and turned to perform well under the wired network. However, it is not ready for the heterogeneous networks. In order to improve the TCP performance over the heterogeneous networks, this paper proposes a modified TCP congestion control...
This paper presents an analytical modeling of ballistic and quasi-ballistic transport, implemented in Verilog-A environment and used for circuit simulation. Our model is based on the Lundstrompsilas approach and uses an expression of the backscattering coefficient given by the flux method. The model takes also into account short channel effects and tales into account the effects of different scattering...
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