Mixing cascaded multi-electric-level converter topology and control method based on T type APF

Abstract

The invention discloses a mixing cascaded multi-electric-level converter topology based on a T type APF. The mixing cascaded multi-electric-level converter topology comprises the T type APF and three single-phase H bridge inverters, wherein the T type APF is used for restraining higher harmonics and high-frequency on-off ripple waves generated by the converters, and the three single-phase H bridge inverters operate at high voltage, medium voltage and low voltage respectively. The three single-phase H bridge inverters are connected in an end-to-end mode to be used for generating multi-electric-level voltage high in quality, and the T type APF is connected with the low-voltage single-phase H bridge inverter. The mixing cascaded multi-electric-level converter topology has the advantages that the defects that the number of modules of a traditional cascaded converter is large, and reliability is low are overcome, and meanwhile the problems that existing mixing cascaded multi-electric-level topology fails to sufficiently utilize the voltage withstanding characteristic advantage of all kinds of power electronic devices, the high-frequency on-off ripple waves and higher harmonics of the converter lead to poor electromagnetic compatibility, and high-frequency resonance between a device and a power grid is prone to being generated are solved. According to the topology structure, the operation voltage of the H bridge units at high voltage, medium voltage and low voltage is allocated according to the proportion of 6:2:1, so that advantages of an IGCT, an IGCB and other semiconductor devices are brought into full play.

Description

technical field [0001] The invention belongs to the technical field of flexible power transmission and distribution and power quality control of power systems, and specifically relates to a hybrid cascaded multi-level converter topology based on a T-type active filter (APF) and the control of the converter method. Background technique [0002] The continuous expansion of power electronics technology in the field of high-voltage and large-capacity provides a broad space for the development of multi-level power conversion circuits. In 1981, Nabae and others first proposed the idea of ​​multi-level conversion circuit. So far, various main circuit topologies have appeared, such as the diode-clamped three-level inverter that has been applied in engineering applications in medium-voltage frequency conversion speed control devices. Applications mainly use integrated gate commutated thyristor (IGCT, Integrated Gate Commutated Thyristors) devices, while the more widely used H-bridge...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the grid-connected reactor in the existing multilevel converter topology is large in size, high in cost, and has poor attenuation effect on high-frequency switching ripple and high-order harmonics, or because of the introduced The passive filter will have high-frequency resonance with the grid impedance, which is not conducive to the stable operation of the device. A hybrid cascaded multi-level converter topology and control method based on a T-type active filter is proposed.

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