This paper presents a pulsewidth modulation (PWM) algorithm for a three-phase ac-dc rectifier, where the third and fifth harmonics are indicated in the input phase voltages. A mathematical analysis, which includes this voltage harmonic's components, shows that the unity input displacement factor (IDF) can be reached by appropriate evaluation of duty-cycle functions. A PWM algorithm is proposed based on this developed theoretical achievement. This approach enables current sensorless unity IDF rectification. The PWM algorithmis investigated theoretically and verified by simulations and experiment.
COBISS.SI-ID: 15236630
This paper presents the derivation of a linear model with changeable parameters of constant frequency peak current mode controlled DC/DC boost converter supplied by a PEM fuel cell stack. The derived model has the same structure irrespective of the conduction mode and therefore, it is suitable for design of simple and advanced controllers of the output voltage. Experimental results on the system with 450 W boost converter supplied by PEM fuel cell emulator show that the derived model accurately describes the system in a given operating point, determined by the load resistance or output current.
COBISS.SI-ID: 15492886
This paper presents a discrete-event switching control of DC-DC converters which belong to a particular class of hybrid systems. Taking advantage of the energetical properties of these converters, Lyapunov function is proposed. This function, which is systematically deduced from the physical model, allows the creation of various stabilizing switching sequences. From a theoretical point of view, asymptotic stability can be obtained. The digital control is implemented by FPGA system, with additional A/D peripherals. Experimental results for digitally controlled synchronous buck converter show the effectiveness of the proposed approach.
COBISS.SI-ID: 14924310
In this paper, we investigate the advantages and feasibility of motor control using very fast (in megahertz) switching in place of traditional amplifiers. We also propose integrated motioncontrol architecture based on discrete-event control approach to be implemented in digital logic at an equally high rate. A switching controller combines the current and motion feedback paths into a single loop. A model-based observer estimates the load torque. When compared to second-order controllers implemented with traditional amplifiers, the proposed design promises increased performance, better efficiency, and improved load estimation. Simple implementation makes concepts of switching control very attractive in motion-control systems like control of dc or ac servomotors. The control algorithm designed by the proposed approach can be easily implemented on field programmable gate array platforms.
COBISS.SI-ID: 13440534