Method for controlling energy storage type converter topology with fault ride-through capability

Abstract

The invention discloses a method for controlling an energy storage type converter topology with fault ride-through capability, wherein the converter topology comprises three phase units, each phase unit comprises an upper bridge arm, a lower bridge arm, an upper bridge arm inductor and a lower bridge arm inductor, and each one of the upper bridge arms and the lower bridge arms of the three phase units is composed of a half-bridge sub-module and a quasi full-bridge energy storage sub-module, which are connected in series in a hybrid manner. The method comprises the following steps: determining modulating waves of each half-bridge sub-module and each quasi full-bridge energy storage sub-module in the bridge arm of each phase according to a to-be-output instruction voltage waveform of each phase, performing comparison according to carriers and modulating waves of each sub-module in the bridge arm of each phase to generate a control signal, and separately controlling the turn-on or turn-off of each sub-module in the bridge arm of each phase. The energy storage type converter topology with the fault ride-through capability can increase the inertia of a new energy system, the charging and discharging current of a battery used for energy storage is smooth, and the voltage level is relatively low, therefore the efficient operation and the safety of the battery are ensured. Meanwhile, the energy storage type converter topology has DC side fault ride-through capability and can still store energy in the case of DC side faults.

Description

technical field [0001] The invention belongs to the technical field of electrical automation equipment, and in particular relates to a control method for an energy storage converter topology with fault ride-through capability. Background technique [0002] In the existing technology, the sub-module with energy storage function directly connects the battery next to the capacitor of the sub-module, so that the battery can withstand the pulsating current of one or two times the power frequency, which has great impact on the efficient operation of the battery and the cost of the whole life cycle. Unfavorable; at the same time, the sub-module capacitor voltage in actual working conditions is generally greater than 1500V voltage level. For high-rate batteries represented by lithium-ion batteries, based on the balance of battery state of charge and fault protection, it is difficult to achieve in terms of cost and safety. Such a high series voltage. In addition, this sub-module wit...

AI Technical Summary

Problems solved by technology

In the event of a DC fault, DC fault ride-through is realized by blocking a part of the sub-modules, and provides reactive power support for the grid through another part of the sub-modules; this patent realizes fault ride-through by blocking the sub-modules and cooperating with the full bridge module and the clamping single sub-module, only Has the ability to ride through faults, but does not have the energy storage function in the event of a fault

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