Virtual synchronous machine (VSM)-based two-level traction rectifier control strategy

Abstract

The present invention discloses a VSM-based two-level traction rectifier control strategy. By a mechanical model simulating a synchronous machine, the frequency of an input voltage of a rectifier is controlled, and by controlling the torque of a virtual machine, the rectifier is controlled to output the active power and a voltage at a DC side. By an electromagnetic model simulating the synchronousmachine, the amplitude of an input voltage of a traction rectifier and the reactive power outputted by a traction network are controlled, and by adding the voltage and frequency supporting links, therectifier can participate in the voltage and frequency adjustment of the traction network. According to the present invention, the traction rectifier can have the outer characteristics of the synchronous machine and has a certain damping characteristic, and by the oscillation of a damping system, an electric locomotive can participate in the voltage and frequency adjustment of the traction network actively while satisfying the own operation status, thereby enhancing the stability of a traction system, and playing an important part in the control of the traction rectifier.

Description

technical field [0001] The invention relates to the technical field of electric traction and electric transmission, in particular to a control strategy of a VSM-based two-level traction rectifier. Background technique [0002] Modern AC electric locomotives generally adopt the AC-DC-AC mode. The front end rectifies single-phase AC power into DC power through a PWM rectifier. The PWM rectifier has the advantages of low power harmonic content, high power factor, and the ability to realize bidirectional flow of energy. . However, the research in the power system shows that although power electronic devices have the advantages of quick response, they also lack inertia and damping characteristics. Therefore, more and more power electronic devices are connected to the power grid, which will reduce the inertia and damping of the entire power grid. characteristic. If the traction network is regarded as a special microgrid, and the electric locomotive is regarded as a special distr...

AI Technical Summary

Problems solved by technology

However, for a special system such as the traction system, there are relatively few related studies. The traction rectifier is essentially a single-phase rectifier, which is neither a three-phase system nor an inverter system. How to apply virtual synchronous machine technology to single-phase two-level In traction rectifiers, further research is required

[0003] In addition, traditional traction rectifier control strategies generally use direct current control or dq decoupling control. Although these two control methods can achieve better DC side voltage control and grid side current phase control, they only As a passive load, it does not have the ability to actively participate in the adjustment of the voltage amplitude and frequency of the traction network

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