The power harmonic components distribution study in the power circuit of a dynamic voltage restorer

Abstract

Purpose. Investigation of the distribution of harmonic power components in the power circuit of a dynamic voltage restorer. Methodology. On the basis of the differential equations of the power circuit of a dynamic restorer, a search for the relationship between the mode parameters and the parameters of the circuit elements is performed. On the basis of the obtained expressions, a model of a dynamic voltage regulator was created using the methods of mathematical modeling in the visual programming environment.. Findings. The equations that reflect the relationship between the mode parameters of a dynamic voltage restorer and the parameters of circuit elements are obtained. As a result of modeling the mode with different harmonic composition of current and voltage, the following features of the distribution of instantaneous power components are revealed. Originality. It has been established that the presence of different current and voltage harmonics acting in the transformer of a dynamic restorer causes additional power harmonics that are transformed in the windings. It is noted that the low-frequency power harmonics of the LC filter dominate on the capacitor, which is connected in parallel to the transformer winding, while the level of high-frequency components caused by PWM modulation for the capacitor and the filter choke differ slightly. The zero-frequency power component of the storage capacitor corresponds to a tripled zero-time power component at the output of the converter, which is due to its operation in three phases. This cannot be extended to the second and third harmonics of the powers of the converter and the capacitor; these components are absent in the latter, which is due to energy exchange processes between the phases of the converter. Practical value. Using the obtained expressions, the principle of determining the parameters of the elements of the power circuit of a dynamic voltage restorer, in particular, the storage elements, is formulated.