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A simulator of photovoltaic generators with programmable electrical characteristics is presented. The proposed system is composed of analog and digital circuits and allows to automatically reproduce in the laboratory the electrical behaviour of PV cells under a variety of solar radiation and temperature conditions.
Numerous power electronic applications necessitate the use of multiwinding transformers. Transformers having n windings per phase have (n−1)2 leakage inductances. Of these, n−1 are self inductances, the rest are mutuals. This paper presents an equivalent circuit for the multiwinding transformer and outlines a method of calculating the leakage inductances for a given transformer of specified winding...
Generating torque in starting of self-controlled synchronous motor is analyzed, and the developed method of torque measurement using the space rotating current vector is described. A self-controlled synchronous motor known as a commutatorless dc motor, consists of a synchronous motor with a shaft position sensor and a inverter switched by the pulses from the position sensor. The inverter frequency...
This paper presents an analytical solution for predicting switching performances of a forward power converter with insulation transformer. We will calculate the circuit wave-forms and especially those which concern the transistor, in relation to the parameters of the adopted converter.
A new coupled-inductor multiple air-gap structure is proposed and analyzed. These EI and EE core configurations eliminate many of the problems associated with the earlier single air-gap structures such as: high sensitivity of ripple currents to air-gap and/or turns ratio changes, complex winding arrangements and consequent high costs and inferior thermal characteristics. To facilitate the design,...
Almost all PWM converters using bipolar transistors experience the problem of reverse transistor conduction. This effect is analysed for various types of base drive. It is shown to be most serious for low impedance direct drives. A mathematical model is developed for this case and verified experimentally. Problems associated with turn-on and turn-off in the reverse conduction mode are investigated.
An improved PWM inverter waveform synthesis technique for harmonic control in delta modulation (DM) process is presented. Filtering approach is incorporated in the DM technique to reduce harmonics of lower frequencies and suppress the unwanted subharmonics. Analytical method is described to determine the performance of multistage delta modulated inverter and the results are substantiated by experimental...
The active power filter is the harmonic filter which suppresses the ac harmonics by injecting PWM compensating current into the ac side. The novel model of PWM compensating current Is derived from the optimized injection method. By injecting the derived PWM current, the ac harmonics up to the order of the modulation number are eliminated. With no external source it is possible to build up the inductor...
In this article, the authors present the design and realisation of a DC/AC inverter. The power cell described is reversible and thus enables the handling of highly reactive loads. A state variable feed-back study leads to the large signal mastery of the power cell. The adaptation of the feedback loop for load variations and source voltage variations are also considered. The article concludes with...
In recent years there has been paid much attention to the development of computer aided methods in analysis and design of power electronic circuits because the recent advances of switching power semiconductor devices. In this paper we propose a new and efficient computer aided algorithm for computing parameter sensitivities of turn-on and turn-off instants of power semiconductors for any given power...
Small-signal model of coupled-inductor Ćuk converter including parasitic minding resistances is derived, and its essential network functions are presented. The basic model is transformed into an easy to use simplified form with analytic expressions for the zeros and poles locations. The dynamic properties of two practically important cases of inductor coupling are discussed and conditions for minimum-phase...
Improved efficiency, better steady-state performance, and reduced complexity were the objectives set for a new control system for reciprocating linear motors. The control system comprises a low-frequency tri-state switching circuit, a linear motor, and an axial position sensor along with three distinct feedback loops (peak-amplitude feedback, average-position feedback, and phase feedback). The system...
The goal of this study is to define the optimal PWM strategy adapted to a given variable-speed induction motor drive. A complete set of simulation programs performs steady-state and transient analysis of wave-forms. Some original PWM modes have been implemented on two digital modulators.
Terminal measurements are made to verify that latching varies with gate drive resistance and occurs during turn off. dv/dt is varied from 1600 to 300 V/us with no impact on latch. A time-displaced turn-off current pulse demonstrates that latching occurs at very low drain voltages, suggesting a tailored gate drive. A brief discussion of device structure explains the observations.
A state space (LQG) controller is designed for a current source self-controlled synchronous motor drive. The controller is implemented using a 16-bit 8086 based microcomputer. This paper described design methodology and controller performance comparison with a non-linear drive digital simulation model.
Algorithms and techniques are presented to tailor the values of circuit elements in fixed-topology circuit models to match data measured from physical inductors and capacitors. Measurements from several types of capacitors and inductors are used to illustrate the results as applied to models of differing complexity.
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