Mikhalsky V. Frequency and Voltage Converters with Pulse-Width Modulation: Analysis, Scientific Substantiation of Means to Improve Quality of Electrical Energy

Object of research: the formation of output voltage and input current of frequency and voltage semiconductor converters. The purpose of research: creation of new methods of pulse-width modulation to generate output voltages and input currents of frequency and voltage semiconductor converters, which consist in determining the stationary states of converters, their mutual arrangement and relative duration at construction of modulation cycles, which improves the quality of these voltages and currents. Research methods: a spectral method for calculations of energy performance, the theory of the linear differential equations, harmonic analysis, elements of matrix calculation, theory of instantaneous power, theory of space vectors, theory of electrical circuits, mathematical and physical modelling. Theoretical and practical results, and novelty: the technique to determine the amplitudes of implementation functions in the formation of voltage source inverter control signals depending on the value of modulation factor has been developed; for the first time the harmonic composition and indicators of quality of VSI output voltage at application of the basic discontinuous modulation functions has been analytically defined; new principles of safe switching of an alternating current by bidirectional switches of matrix converters has been developed; a new method for the formation of currents in the system "power supply with asymmetric voltages - the matrix converter" has been developed; the new concept of compensation of the "dead time" in the frequency converters with PWM has been developed; the new method for correcting the durations of the stationary states of matrix converter with PWM by definition of the error vector has been developed. Degree of implementation: frequency converters PT3-220-400 based on VSI, which are mass-produced by DerzhKKB "Luch", Kyiv are developed. Sphere of use: frequency and voltage converters with pulse-width modulation.