Double-random SVPWM modulation SVG dual-sequence synchronization control method

Abstract

The invention discloses a double-random SVPWM modulated SVG double-sequence synchronous control method, which comprises the following steps: 1. Detecting load current, SVG output current, DC side capacitance voltage and grid voltage; 2, compensate that positive sequence component and the negative sequence component respectively by adopting the positive and negative two-sequence control strategy; 3, acquiring a voltage command signal; 4, that drive signal of the bridge circuit is obtained by the double random SVPWM control method, the power switch transistor is controlled, and the reactive power and the negative sequence current component are compensated. So that that structure of the invention is clear, not only can the reactive current component and the negative sequence current componentcaused by load unbalance be compensated accurately, At that same time, the harmonic characteristic of SVG power bridge circuit is consider, and the harmonic peak of output current and line voltage issuppressed by using the double random SVPWM modulation method, which can reduce the harmonic pollution of SVG to the power system when the SVG is in grid-connected operation.

Description

technical field [0001] The invention belongs to the technical field of static var generator control, and in particular relates to an SVG double-sequence synchronous control method modulated by double random SVPWM. Background technique [0002] With the increasing size of the power system, various power consumption conditions are becoming more and more complex, and users have higher and higher requirements for power quality. However, with the aggravation of the three-phase unbalance of the power grid, it has seriously affected the safety and stability of the power grid. run. Especially with the connection of large-capacity impact asymmetric loads such as electric railways, rolling mills, and single-phase motors, a large amount of negative sequence currents are generated in the grid, and these loads also absorb a large amount of reactive power from the grid when they are working. Comprehensively comparing many power electronic compensation devices, the static synchronous comp...

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Problems solved by technology

For grid-connected SVGs, this is undoubtedly detrimental to the power quality of the grid

In addition, because the traditional SVPWM uses a definite form to control the turn-on and turn-off of the power switch tube, some high-order harmonics with large amplitudes will be generated in the output current and voltage, and these harmonics are mainly concentrated at the carrier frequency and its integer multiple frequency, which seriously affects the power quality

In contrast, the random SVPWM technology can further reduce the high-order harmonic peak value of the SVG output voltage and current, and can further reduce the total harmonic distortion rate of the current. However, there is still a lack of good application of the random SVPWM technology in the prior art to the method in the SVG run control

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