An active filter and a method for eliminating the secondary resonance of the DC bus of a train

Abstract

A method for eliminating second harmonics of a direct current bus of a train. The method comprises an active filtering device connected to the direct current bus, and specifically comprises a buck / boost bidirectional DC / DC converter (DC-APF), a filtering inductor (Ls), and an energy storage capacitor (Cs). According to a power balancing principle, when a secondary pulse of a bus voltage is fully compensated, a secondary pulse power output by a single-phase regulator needs to be controlled to have the same size as, and opposite polarity to, a secondary pulse power compensated by the active filtering device. The device utilizes a control system combining a current loop and a voltage loop, and performs closed-loop control according to actual electrical quantities detected by the system, such as a voltage and a current, thereby ensuring a compensation effect and a dynamic response capability of the system during actual operations of a train, improving system stability. The device replaces conventional passive LC filtering, and overcomes the drawback of passive filtering in which only harmonics at a fixed frequency can be compensated for, thereby providing adaptability to complex power grid environments, and providing an improved effect compared to conventional methods. The device reduces the volume and weight of a traction transmission system, lowers costs, and increases the power density of an inverter.

Description

technical field [0001] The invention relates to a rail transit single-phase power supply system, in particular to a vehicle-mounted traction converter AC-DC-AC system. Background technique [0002] Because of its simple structure, strong reliability, and high efficiency, single-phase converters are not only used in locomotive traction converter systems, but also in uninterruptible power supplies, photovoltaic grid-connected, cascaded multi-level converters, multi-phase AC drives, aviation It has been widely used in various power electronic systems such as aerospace power supplies. At present, most of the world's high-speed trains use modern AC drive systems. The AC-DC part of the traction drive system adopts single-phase PWM rectification with four-quadrant operation, which can feed back the energy of the locomotive during braking to the grid, and at the same time make the system have a higher efficiency. power factor. However, the single-phase system will generate inheren...

AI Technical Summary

Problems solved by technology

[0004] The present invention provides an active filter and a method for eliminating the secondary resonance of the train's DC bus to solve the inherent shortcomings of traditional passive LC resonant devices, thereby increasing the power density of the vehicle and reducing costs

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