Fast three-phase space vector modulation method based on three-dimensional coordinate system

Abstract

A fast three-phase space vector modulation method based on a three-dimensional coordinate system belongs to the technical field of power electronics. At first, that vector is map from a two-dimensional coordinate system to a three-dimensional coordinate system by using a simple coordinate change, three modulation vectors are used to synthesize the reference voltage vector, Three modulation vectorsform a modulation triangle in the three-dimensional coordinate system, detect the closest modulation vector to the origin in the modulation triangle, calculate the three-phase switching state corresponding to the vector and map it to the three-dimensional coordinate system, and scale the reference voltage vector to simplify the multilevel vector space to the two-level vector space; Finally, the duty cycle of the three-phase switching state is calculated and compared with the triangular carrier of the converter to generate the switching driving signal. The invention can realize arbitrary leveloutput only through simple addition and subtraction operation, and has extremely strong expansibility; In addition, the present invention provides several controllable factors to improve the performance of various aspects of multilevel converters.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and relates to a modulation algorithm of a three-phase multilevel converter, especially in the application of modulation algorithms using digital chips such as FPGA and DSP as control chips. Background technique [0002] Space Vector Modulation (SVPWM) is a pulse width modulation method based on the concept of space voltage vector synthesis, which has been widely used in power electronic modulation. Its core idea is to use the different switching states of the converter as the basic action vectors, and synthesize the reference vectors according to the selected basic vectors and their specific action time. Compared with the ordinary PWM modulation algorithm, it has many outstanding advantages: high utilization rate of voltage, easy digital realization, good output waveform quality, close to sinusoidal, reasonable arrangement of space vector, can reduce switching frequency, reduce switchi...

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Problems solved by technology

[0004] Aiming at the inadequacies of the above-mentioned existing SVPWM algorithm that is not easy to expand and cannot completely cancel the multiplication and division and trigonometric function operations, the present invention provides a fast three-phase space vector modulation method based on a three-dimensional coordinate system, which is suitable for three-phase multiple The level converter, the present invention has both the advantages of all the traditional fast SVPWM algorithms and realizes that there is no multiplication, division and trigonometric f

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