Method for virtual inertia control of bidirectional AC/DC converter

Abstract

The invention discloses a method for virtual inertia control of a bidirectional AC / DC converter. The method mainly comprises three parts, namely virtual inertia control, output current feedforward control and voltage and current double loop control. By the virtual inertia control, a DC side of the bidirectional AC / DC converter has relatively large virtual inertia, voltage fluctuation of a DC bus can be stabilized, the voltage-current sagging function can be achieved, and expansion of the system capacity by the bidirectional AC / DC converter through parallel connection is facilitated. By the output current feedforward control, the influence of a sudden change of power of the DC side on the DC bus voltage can be reduced, and the transient response performance of the system is improved. Proportional integral control is adopted by a DC voltage outer loop, a DC voltage command can be tracked without a static error; and feedforward decoupling control under a synchronous rotating reference frame is adopted by a grid-connected current inner loop, and a relatively low power grid current distortion rate can be ensured. By the virtual inertia control method, the DC side of the bidirectional AC / DC converter has relatively high inertia, great fluctuation of the DC bus voltage caused by the sudden change of the power of the DC side can be stabilized, and the voltage quality of the DC bus is improved.

Description

technical field

[0001] The invention relates to the control field of a bidirectional AC / DC converter, in particular to a virtual inertia control method of the bidirectional AC / DC converter. Background technique

[0002] The promotion of distributed generation such as photovoltaics, wind power, and energy storage and the increasing proportion of DC loads in terminal power consumption have promoted the development of DC microgrids. As the grid-connected interface unit of DC microgrid and large power grid, bidirectional AC / DC converter plays a key role in controlling energy exchange between DC microgrid and large power grid, maintaining DC bus voltage stability and improving system operation efficiency. However, the DC microgrid is a low-inertia network dominated by power electronic converters. Frequent switching of loads and sudden changes in the output power of distributed micro-sources will cause large fluctuations in the DC bus voltage, which is critical to the safe, effici...

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