Virtual synchronous motor control method and device based on virtual impedance self-adaption

Abstract

The invention discloses a virtual synchronous motor control method and device based on virtual impedance self-adaption, and the method and device are applied to each inverter in a virtual synchronous motor multi-machine system, and the method comprises the steps: building a virtual synchronous motor controller which is used for controlling the inverters to form a virtual synchronous motor; obtaining the angular frequency of the neighbor virtual synchronous motor, and constructing virtual impedance for the local virtual synchronous motor according to the angular frequency difference between the local virtual synchronous motor and the neighbor virtual synchronous motor; and finally, through the constructed adaptive virtual impedance, the output equivalent inductive reactance of the local virtual synchronous motor is changed. According to the invention, the frequency dynamic performance of the virtual synchronous motor can be improved, so that the power oscillation among the multiple virtual synchronous motors is inhibited.

Description

technical field [0001] The invention belongs to the field of microgrid control, and more particularly relates to a method and device for controlling a virtual synchronous motor based on virtual impedance self-adaptation. Background technique [0002] The penetration rate of distributed generation (DGs) in the power system has increased significantly, leading to great changes in modern power systems, especially the continuous reduction of power system inertia provided by synchronous generators. Since most distributed energy sources, such as photovoltaics, wind energy, fuel cells, microturbines, and energy storage systems, are connected to the grid through power electronic converters, and power electronic converters have the characteristics of fast response and small inertia, which is not conducive to grid dynamic frequency stability. [0003] However, high inertia is usually desired in power systems, as it can effectively avoid undesired shedding or large-scale blackouts. T...

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Problems solved by technology

For synchronous motors, this is not a critical issue due to their considerable overload capability; however, the overload capability of power electronic converters is not high enough to withstand large oscillations

Although, appropriately increasing the damping ratio or using the alternating moment of inertia and designing a smaller inertia coefficient may also lead to a decrease in oscillation, since providing a large virtual inertia is an advantage of the virtual synchronous motor that distinguishes it from other control methods, so the above Neither method is optimal

Especially in multi-machine systems, the power oscillation problem is more complicated and serious

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