Showing papers by "Johann W. Kolar published in 1993"

Space vector-based analytical analysis of the input current distortion of a three-phase discontinuous-mode boost rectifier system

Abstract: In this paper the low frequency harmonic distortion of the mains current of a three-phase single-switch discontinuous-mode boost-rectifier is calculated. The system analysis is based on application of space vector calculus and on substitution of discontinuous time shapes within a pulse period by quasicontinuous time shapes. The quasicontinuous time shapes are defined by averaging over the pulse period. The dependency of the shape of the input currents on the voltage transformation ratio is given for various control methods in analytical form. The results of the theoretical analysis are verified by digital simulation and by measurements on a laboratory model. A good consistency of the results has been found. >

A comprehensive design approach for a three-phase high-frequency single-switch discontinuous-mode boost power factor corrector based on analytically derived normalized converter component ratings

Abstract: In this paper the peak, mean, and RMS values of the component currents of a three-phase single-switch discontinuous inductor current mode boost rectifier are calculated analytically. The values are given in rated form in dependency on the output power and on the ratio of output voltage to the amplitude of the mains voltage. Furthermore, the influence of the voltage transfer ratio on the shape of the mains currents and on the power factor of the system is analyzed. The theoretical analysis is verified by digital simulation and a good consistency is achieved. Finally, the approach of the converter dimensioning based on the graphical representation of the calculation results is described and illustrated using a specific example. The correctness of the dimensioning is verified by measurements on a laboratory model. >

Quasi-dual modulation of three-phase PWM converters

Abstract: The possibility of transferring the modulation method developed for a pulse width modulated (PWM) power converter with a DC voltage link (VLC) to a PWM converter with a DC current link (CLC) based on the inverse current and voltage behavior of these two systems is evaluated. The duality between VLC and CLC, which has been intuitively clear, is treated here in a scientific approach. It is shown that the nonplanar property of three-phase bridge circuits leads to a quasi-dual relation of the switching states of the VLC and CLC systems. The code conversion of the binary switching functions of a VLC into control signals of the power electronic devices of a CLC is given. The remaining degree of freedom of the correspondence is set by the requirement of minimum switching frequency of the converter. >

A novel single-switch three-phase AC/DC buck-boost converter with high-quality input current waveforms and isolated DC output

Abstract: A new three-phase single-switch AC-DC flyback power converter system is presented. The system operates in the discontinuous mode. The simple structure of its power and control circuit, low mains current distortion and resistive fundamental behavior as well as the high-frequency isolation of the controlled output voltage are pointed out. Besides the analysis of the stationary operating behavior the dependencies of the peak values, average values and RMS values of the device currents and of the maximum blocking voltages across the power electronic devices on the circuit parameters are given as analytic approximations. The theoretical analysis is verified by digital simulation. >