High-power-density single-phase cascaded H-bridge rectifier, control method and control system

Abstract

The invention provides a high-power-density single-phase cascaded H-bridge rectifier, a control method and a control method. The high-power-density single-phase cascaded H-bridge rectifier comprises an AC network side filter inductor and at least two cascaded power conversion units, wherein each power conversion unit comprises an H-bridge power unit, a decoupling unit and a DC side equivalent loadwhich are connected in parallel; wherein each decoupling unit is an independent buck type active power decoupling loop, and the decoupling units are used for buffering secondary ripple power so as toreduce the capacity of a DC bus capacitor.

Description

technical field [0001] The disclosure belongs to the field of cascaded multilevel converters, and in particular relates to a high power density single-phase cascaded H-bridge rectifier, a control method and a control system. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] Cascaded multi-level power electronic transformer (PET, Power Electronic Transformer) power converter, there is a double frequency power pulsation on the DC side, in order to reduce the DC bus voltage ripple, you can use additional filter capacitors or passive LC secondary filtering However, the inventors found that this increases the weight and volume of the system, especially the nonlinear magnetic core characteristics of the LC filter network are distorted under the action of harmonic currents, which easily leads to system instability. [0004] Increasing the capacit...

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Problems solved by technology

[0003] Cascaded multi-level power electronic transformer (PET, Power Electronic Transformer) power converter, there is a double frequency power pulsation on the DC side, in order to reduce the DC bus voltage ripple, you can use additional filter capacitors or passive LC secondary filtering network, but the inventor found that this increases the weight and volume of the system, especially the nonlinear magnetic core characteristics of the LC filter network are distorted under the action of harmonic currents, which can easily lead to system instability

[0004] Increasing the capacitance can certainly reduce the voltage ripple, but the inventor found that the size and cost of the cascaded multi-level power electronic transformer will increase, which is not conducive to the improvement of the power density of the airborne cascaded multi-level PET

In the case where the system DC voltage pulsation and the contradiction between system cost and volume cannot be reconciled, the voltage margin of the power switch module has to be increased, which will inevitably reduce system reliability and power conversion capability

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