Voltage equalizing circuit, flying capacitor three-level converter and equipment

Abstract

The invention provides a voltage equalizing circuit, a flying capacitor three-level converter and equipment. A first switching tube, a second switching tube, a third switching tube and a fourth switching tube in the flying capacitor three-level converter are sequentially connected in series; the first switching tube and the fourth switching tube are connected with a high-voltage port; the third switching tube and the fourth switching tube are connected with a low-voltage port; the flying capacitor is connected in parallel between the first end of the second switching tube and the second end ofthe third switching tube; the voltage equalizing circuit comprises a first equalizing element, a second equalizing element, a third equalizing and a first equalizing branch, and the first equalizingelement is connected to the two ends of the first switching tube in parallel; the second equalizing element is connected in parallel between the first end of the second switching tube and the second end of the third switching tube; the third equalizing element is connected in parallel with two ends of the fourth switching tube; and the first equalizing branch is connected in parallel with the twoends of the third switching tube, thereby reducing the possibility of overvoltage of the flying capacitor, improving the voltage balance when the circuit is started, and accelerating the dynamic response.

Description

Technical field [0001] The present invention relates to the field of circuit technology, and more particularly to a unit pressure circuit, a flying cross-capacitor three-level converter, and a device. Background technique [0002] Non-quarantined DC converters are widely used in rail transit, power, new energy power generation, energy storage, high power transmission. Flying across capacitors three-level converters have advantages to the use of less components, flexible, efficient, and is more likely to obtain product application. In these devices for these applications, the flying across the capacitor three-level converter needs to turn off the machine frequently, and each time the shutdown of the flying across the capacitor three-level converter needs to shut down the circuit breaker. When you replay it again, you need to build a flying across capacitor voltage, then close the corresponding circuit breaker, and the open process usually requires at least few seconds to complete,...

AI Technical Summary

Problems solved by technology

[0004] However, in standby mode, the flying capacitor voltage is no longer determined by the high-voltage side voltage, but is generated by the joint excitation of the high-voltage side voltage and the low-voltage side voltage. The existing flying capacitor three-level converter may have a flying capacitor voltage The problem of unbalance may cause overvoltage of the flying capacitor, and the reliability is not high enough

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