Distributed virtual synchronous-generator low voltage crossing control method

A low-voltage ride-through and virtual synchronization technology, which is applied in the direction of emergency protection circuit devices, electrical components, circuit devices, etc. for limiting overcurrent/overvoltage, can solve the requirements that do not involve reactive current injection and cannot meet low voltage Overcoming the requirements of relevant standards and other issues to achieve the effect of enhancing reactive power support capability, improving control accuracy and response speed, and suppressing steady-state overcurrent

Active Publication Date: 2018-05-29
NANCHANG UNIV
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  • Abstract
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Problems solved by technology

[0004] Most of the above studies on LVRT of VSG focus on the limitation of output current, and do not involve how to meet the ...

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  • Distributed virtual synchronous-generator low voltage crossing control method
  • Distributed virtual synchronous-generator low voltage crossing control method
  • Distributed virtual synchronous-generator low voltage crossing control method

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Embodiment Construction

[0042] The present invention will be further described below in conjunction with accompanying drawing and working principle.

[0043] Such as figure 1 As shown, the present invention is based on the VSG-based LVRT technology, mainly through virtual impedance control and virtual synchronous balanced current control, to suppress the fault instantaneous current and steady-state current overcurrent when the short-circuit fault of the distribution network causes the voltage drop at the grid-connected point, and By changing the given value of reactive power to achieve the purpose of injecting the specified reactive current, the control target of grid-connected inverter LVRT based on VSG control is realized.

[0044] Such as figure 2 As shown, the control method of the embodiment of the present invention includes the following steps:

[0045] 1. Sampling to obtain grid voltage u gabc , capacitor voltage u cabc , Converter side inductor current i 1abc and grid side output curren...

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Abstract

A distributed virtual synchronous-generator low voltage crossing control method is disclosed. The method comprises the following steps of using an improved virtual synchronous generator reactive powerring to accelerate a response speed of the reactive power ring and increase a reactive power support capability to a grid connection point; when a grid connection point voltage is detected to drop and an instantaneous overcurrent is detected, introducing virtual impedance control, correcting a voltage reference value and restraining the instantaneous overcurrent; using a balance current virtual synchronization control method to control positive and negative sequence currents, and when a grid connection voltage is imbalance, realizing balance control of an output current and restraining a stable state overcurrent; and according to a low voltage crossing requirement, resetting a power instruction value so that a system satisfies a reactive current injection requirement, and after a fault isremoved, setting the power instruction value to an original value. Through the above steps, low voltage crossing requirements of instantaneous and stable state overcurrent restraining, reactive current injection according to the requirement and the like are satisfied.

Description

technical field [0001] The invention belongs to the field of grid-connected inverter control, and in particular relates to a low-voltage ride-through control method of a distributed virtual synchronous generator. Background technique [0002] Virtual Synchronous Generator (VSG) control strategy simulates the characteristics of active power frequency regulation and reactive power voltage regulation of synchronous generators, so that the distributed inverter power supply is similar to traditional synchronous generators in terms of operating mechanism and external characteristics, and can provide The grid provides certain inertia and damping support. However, most of the existing VSG research focuses on the VSG ontology model and the ideal grid state, but less about its fault ride-through capability. Distributed VSGs are mostly connected to medium and low voltage distribution networks, and short-circuit faults that threaten the system are prone to occur. When a short-circuit ...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/18H02J3/26H02H9/02
CPCH02H9/02H02J3/18H02J3/26H02J3/38H02J2203/20Y02E40/30Y02E40/50
Inventor 万晓凤丁小华胡海林詹子录汪建博
Owner NANCHANG UNIV
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