Composite chain-type high-voltage active filtering device

Abstract

The invention relates to a composite chain-type high-voltage active filtering device, which comprises a power supply, a user load, and three chains arranged between the power supply and the user load, wherein each chain comprises multiple mutually-parallel sub chains for compensating different amplitude harmonics; and each chain comprises multiple sequentially-cascaded chain units. In comparison with the prior art, as each chain comprises multiple mutually-parallel sub chains, a hybrid harmonic can be decomposed into components with different amplitudes, the components with different amplitudes are given to different chains in the phase for compensation, and thus, the peak of output current of each chain is reduced, the safety of the device and the safety of the equipment are facilitated, full use of a unit capacity is made, and the control is more convenient.

Description

technical field [0001] The invention relates to a filter device, in particular to a composite chain-type high-voltage active filter device. Background technique [0002] Traditional high-voltage active filters are generally implemented in a cascaded manner. figure 1 Shown is the structure diagram of a traditional high-voltage chain-type active power filter. Each phase link is formed by cascading N single-phase H-bridge circuits to achieve high-voltage output. In practical applications, the number N of cascaded units is reasonably selected according to the requirements for capacity, output voltage, harmonics, and cost. Each H-bridge unit uses IGBT as a circuit switch device, and controls the on-off of the IGBT through pulse width modulation (PWM) technology, which can convert the DC voltage on the DC side capacitor into an AC voltage with a certain frequency and amplitude. The bridge unit uses capacitors for voltage support, which is equivalent to an independent DC power su...

AI Technical Summary

Problems solved by technology

However, as the capacity of power electronic devices increases, the allowable switching frequency becomes lower and lower, so when APF is used for large-capacity harmonic compensation, it faces the contradiction between device switching frequency and capacity

When the harmonics of the load are mixed harmonics of multiple frequencies and different amplitudes, if a single chain link compensation is used, the peak value of the mixed harmonics may be very large, which will cause certain difficulties in the control compensation, and also affect the device itself. certain risk

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