Four-quadrant cascade high-voltage frequency conversion device

Abstract

The invention discloses a four-quadrant cascade high-voltage frequency conversion device, which comprises a transformer, three single-phase electric reactors and three groups of power module units, wherein a secondary side of the transformer is provided with three single-phase windings; each group of power module units consists of N module units; each power module unit consists of two identical controllable H-bridge circuits; two input ends and two output end are respectively formed through the two H-bridge circuits; in the same power module unit, the input ends of the power module unit are connected in sequence, and output ends of each power module unit are connected in sequence; and two power modules at the head and the tail are connected with single-phase secondary windings of the transformer. Bidirectional flow of energy between a power grid and a load is realized, the high voltage resistance of the whole frequency conversion device is realized, the defect that a plurality of secondary side windings are adopted in prior art is overcome, and the usage of electric reactors is greatly reduced, so that the whole high-voltage frequency conversion device is relatively simple in structure, low in manufacturing cost, small in volume, heavy in weight and convenient to transport, mount and maintain.

Description

technical field [0001] The present invention relates to a four-quadrant cascaded high-voltage frequency conversion device, more specifically, to a four-quadrant cascaded high-voltage inverter in which the secondary of the transformer is a three-phase winding, a plurality of power modules are connected in series, and energy can flow bidirectionally. frequency conversion device. Background technique [0002] At present, ordinary cascaded high-voltage frequency conversion devices are composed of isolated phase-shifting transformers and multiple power modules. They are mainly used for loads such as fans and pumps. Generally adopt the form of uncontrolled rectification. [0003] At present, the cascaded high-voltage frequency conversion can carry out bidirectional flow of energy by using three-phase PWM controllable rectification as the input. The rectification form in each power module is changed from ordinary diode uncontrolled rectification to PWM controllable by electronic s...

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned ordinary cascaded high-voltage frequency conversion device and the frequency conversion device with two-way energy flow, its input is an isolated phase-shifting transformer, and the secondary of the transformer is a multi-winding winding, which is characterized by many windings and many phase-shifting angles. The conditions are relatively strict, such as the impedance requirements of each winding are basically the same, otherwise the harmonic influence on the input current is more obvious, and a series of problems and shortcomings such as difficulty in the production of the transformer are also raised.

Moreover, among the existing PWM controllable frequency conversion circuits capable of bidirectional energy flow, there is no circuit topology that uses "AC-AC" for direct frequency conversion and energy flow.

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