High-performance four-quadrant frequency converter

Abstract

The invention discloses a high-performance four-quadrant frequency converter which achieves the purposes that output direct current voltage is controllable, harmonic content of current at the network side is small, the energy can flow in double directions, intermittent operation law is realized and the energy is saved. The direct current side voltage can be kept at a set value by control no matter the frequency converter is in heavy load or light load, and even energy feeds back. The control method comprises the steps of carrying out unified coordinate control on the combination of a rectifier and an inverter, and carrying out feedforward control by the information at the inverter side to obtain good direct current bus voltage control performance and rapid dynamic response speed by the rectifier. The purpose of intermittent operation is achieved by matching the operation law of the rectifier with the operation law of a motor at the inverter side; and bidirectional flow of energy can be achieved so as to save electric energy. The high-performance four-quadrant frequency converter has the characteristics that the harmonic content of the current at the network side is low, the sine degree is high, harmonic pollution on a power grid does not exist, the rectifier runs by the unit power factor, an automatic booster function is achieved, and the voltage stability of the direct current bus can be controlled.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a high-performance four-quadrant frequency converter for driving a permanent magnet synchronous linear motor. Background technique [0002] The front end of the traditional inverter for motor drive often uses a diode rectifier bridge to convert AC power into DC power. The main problems of this inverter structure are: [0003] 1) The input current contains large harmonics. Due to the characteristics of the diode rectifier bridge, the input current cannot be directly controlled, and the current THD (Total Harmonic Distortion Rate) is generally above 40%, resulting in increased input line loss and electromagnetic interference problems, which are important reasons for the current power grid pollution. The pollution problem It will become more and more serious with the increasing application of converters in grid equipment. [0004] 2) Absorbing reactive power from the grid, low inp...

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Problems solved by technology

[0011] In view of the above situation, the object of the present invention is to provide a high-performance four-quadrant inverter, which overcomes the problems of large input harmonics, inability to flow energy in both directions, non-adjustable power factor, and uncontrolled DC voltage in traditional motor-driven inverters. The problem of uncoordinated rectification side and inverter side

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