A megawatt-level broadband impedance measurement device and its control method

Abstract

The invention discloses a megawatt broadband impedance measurement device and a control method thereof. The device can be connected to a 35kV to-be-tested new energy grid connected power generation system. The device comprises a voltage disturbance injection unit; multiple power module units are cascaded to form the voltage disturbance injection unit; six sub power module units are cascaded in each phase of three phases; output of each phase is connected with the primary edge of a coupled transformer through an LC filter circuit, the secondary side of the coupled transformer is connected to a to-be-tested system, and a voltage disturbance source is provided. A high-frequency isolated DC / DC converter adopts voltage outer-loop PI current P double-closed loop control, and stable DC voltage is provided for a single-phase H-bridge converter; and a cascaded H-bridge converter adopts voltage outer-loop quasi proportional resonant current inner-loop proportional control, and on and off of a power device of an H-bridge converter in each phase are controlled through carrier phase-shifted SPWM multilevel modulation. Thus, the system has high reliability and quicker dynamic response, and requirements that the system is applied to megawatt high-power occasions and broadband disturbance output impedance measurement can be met.

Description

technical field [0001] The invention relates to the technical field of impedance measurement in new energy power generation, in particular to a megawatt-level broadband impedance measurement device and a control method thereof. Background technique [0002] With the depletion of fossil energy and the intensification of environmental problems such as global warming, the development and utilization of new energy has become the best choice for people to seek energy structure adjustment and achieve sustainable development. When analyzing large-scale new energy power generation equipment connected to the grid, the impedance characteristics of the grid have an important impact on the stable operation and control of power electronic equipment such as wind power and photovoltaic grid-connected inverters. Ideally, the grid should behave as an ideal voltage source, and the new energy power generation equipment should be controlled as an ideal current source to avoid any impedance inte...

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Problems solved by technology

In new energy power generation bases, the external characteristics of power generation equipment vary greatly, and factors such as grid disturbances and new energy fluctuations make the measurement of impedance characteristics of power generation equipment more complicated, and there is a lack of impedance for power generation equipment such as megawatt wind turbines and photovoltaic power generation units. The characteristic data are difficult to meet the refinement requirements of the power generation equipment simulation model in the new energy power generation base, and the precise measurement methods and equipment for high-voltage, megawatt-level, and broadband impedance characteristics are blank at home and abroad, and key technologies need to be broken through

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