Alternating-current push-pull conversion-full-bridge rectification step-down circuit

Abstract

The invention discloses an AC push-pull conversion-full-bridge rectification step-down circuit in the field of power electronics technology, which includes a high-frequency conversion circuit and an impedance conversion circuit. The output end of the high-frequency conversion circuit is connected to the input end of the impedance conversion circuit. The high-frequency conversion circuit includes sequentially cascaded filter circuits, primary and secondary transformers with center taps, first and second push-pull circuits; the impedance conversion circuit is a fully-controlled bridge rectifier circuit with a parallel filter capacitor at the output end, The midpoints of the two bridge arms of the bridge are respectively connected to the two AC output terminals of the second push-pull circuit, and the output terminals of the rectifier bridge output DC voltage. The invention outputs stable DC voltage and generates unit input power factor at the same time, realizes flexible voltage regulation capability and obtains linear input impedance, overcomes the deficiency of mutual interference between power supply and load fluctuation, supports four-quadrant operation in addition, and can feed back DC voltage to AC The power grid makes full use of idle power on the load side, has strong versatility, simple structure, and low cost.

Description

technical field [0001] The present invention relates to an AC-DC converter in the technical field of power electronics, in particular to an AC push-pull conversion-full-bridge rectification step-down circuit, that is, an AC-DC converter for bidirectional flow of energy in AC conversion . Background technique [0002] With the development of my country's smart grid, the proportion of distributed power generation systems such as solar power, wind power and small hydropower in the entire energy structure is gradually increasing. Distributed power supply has small capacity, wide distribution, both AC and DC power supply, and the power supply voltage or frequency has large fluctuations. The small size, light weight, AC push-pull conversion-full bridge rectification step-down circuit can flexibly connect various distributed power sources to the power system, and has a good application prospect. [0003] The power electronic transformer with two-way flow of energy specifically in...

AI Technical Summary

Problems solved by technology

The direct AC-AC converter with single-phase input has a simple circuit, easy control, and low cost, but its function is limited, its voltage regulation and frequency conversion capabilities are poor, its low-voltage ride-through ability is poor, and its input power factor is low.

If it is not handled correctly, the power factor of the power frequency high-voltage AC power supply will not be 1, and a large amount of harmonic current will cause various hazards, so it must be dealt with

The three-phase input direct AC-AC converter has complete functions and high performance, but its circuit is complicated, the control is cumbersome, the cost is high, and the low-voltage ride-through ability is poor.

The limitations of this solution make it impossible to keep up with the development of technology and cannot meet the requirements of smart grid, so it will be eliminated

[0007] In summary, the direct AC-AC converter has the disadvantages of complex control and low input power factor, and the indirect AC-AC converter needs input power factor correction to reduce Harmonic interference on the grid side is not suitable for high-voltage AC input-low-voltage AC or low-voltage DC output applications, and the traditional uncontrollable rectifier bridge PFC correction circuit cannot meet the requirements of bidirectional power flow

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