A hybrid cascaded seven-level active filter based on composite control

Abstract

The invention discloses a compound control based hybrid cascading seven-level active filter. The compound control based hybrid cascading seven-level active filter comprises an H-bridge hybrid cascading main circuit (3), a sampling circuit (4), a control circuit (5), and a pulse width modulation (PWM) and isolation drive circuit (6), wherein the ratio of the DC side voltages of two H-bridge units in the H-bridge hybrid cascading main circuit (3) is 1: 2, the control circuit (5) comprises a main power signal generation module (7), a power compensation signal generation module (8), and a compound control module (9), the main power signal generation module (7) generates a main control signal, the power compensation signal generation module (8) generates a power compensation signal, the compound control module (9) is used for generating a first control signal and a second control signal, and the PWM and isolation drive circuit (6) is used for generating a final switch tube drive signal. Compared with traditional isobaric cascading active filters, the compound control based hybrid cascading seven-level active filter can output more levels under the same number of units, so that effects of harmonic compensation are improved.

Description

technical field [0001] The invention relates to a hybrid cascaded seven-level active filter based on composite control, which is suitable for various medium and high power occasions and belongs to the technical field of electric harmonic suppression. Background technique [0002] In recent years, power electronics technology and devices have been developed rapidly. While improving people's living standards, it also brings a large number of nonlinear loads to the power grid, especially the converters that work in switch mode. These nonlinear loads will generate a large number of harmonics and reactive power. If they are injected into the grid, the grid current and grid voltage will be distorted. In severe cases, it may threaten the safe operation of the grid. Therefore, the suppression and management of harmonics is very important. , is an important research topic in power electronics and other fields in recent years. [0003] Active filter is a device that can dynamically s...

AI Technical Summary

Problems solved by technology

Most of the methods are aimed at the control of equal-voltage H-bridge cascading, and there are few studies on hybrid cascading control, such as using additional hardware devices to control the stability of the DC side voltage. Although this method can stabilize the DC side voltage at the required value, but at the same time it also increases the cost and volume of the system; it is also possible to control the voltage stability of the DC side by shifting the output waveform phase, but due to the limited range of phase shift angles, the voltage stability of the H-bridge DC side is slow and the dynamic performance poor

ManjrekarMD, SteimerPK, and LipoTA, "Hybrid multilevel power conversion system: competitive solution for high-power applications," IEEE Transactions on Industry Applications, 2000, 36 (3): 834-841 proposes a PWM rectifier composed of fully-controlled power devices to control the DC side voltage of the low-voltage unit for the hybrid cascaded topology Stability, which will increase the complexity of system control, reduce the efficiency of the system, increase the volume and cost of the system

MiguelLopezG, LuisMoranT, and JoseEspinozaC, etal, "Performanceanalysisofahybridaasymmetricmultilevelinverterforhighvoltageactivepowerfilterapplications," IEEEIECON, 2003: 1050-1055 did not use external equipment, but controlled the system through a hybrid control method, which achieved certain compensation effects, but the article did not Analyze the dynamic performance when the load changes suddenly, the reliability is not high

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