Double-resonance injection type broadband impedance measuring device and control method thereof

Abstract

The invention discloses a double-resonance injection type broadband impedance measuring device and a control method thereof. The measuring device comprises a current disturbance injection unit, a signal processing unit and a broadband impedance calculation and monitoring unit; each phase of the current disturbance injection unit is cascaded with 6 sub-power module units; the output of each phase of the current disturbance injection unit is connected into a system to be tested through a disturbance injection branch; and the disturbance injection branch combines the advantages of a series resonance branch and a parallel resonance branch, and therefore, a cascade power module can withstand a small fundamental voltage, most of disturbing current is injected into the system to provide a currentdisturbance source. According to a cascaded H-bridge converter, a voltage outer loop adopts proportional plus integral control, and a current inner loop adopts quasi-proportional resonance control; and the turning on and turning off of the power devices of H-bridge converters in each phase are controlled through carrier phase-shift SPWM multilevel modulation. With the control method adopted, thesystem has higher reliability and faster dynamic response and can meet the requirements of the application of the system to megawatt-level high-power conditions and wideband disturbance output impedance measurement.

Description

technical field [0001] The invention relates to the field of impedance measurement in new energy power generation, in particular to a dual-resonance injection 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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