Dynamic voltage correction device, correction method and isolation method for load short-circuit fault

Abstract

The invention provides a dynamic voltage correcting device. The dynamic voltage correcting device comprises a first convertor composed of L, S5, S6, C1 and C2, a second convertor composed of D1, D2, S1, S2, S3 and S4, an LC filter composed of Lf and Cf and a bilateral switch. A terminal a and a terminal b are alternating current input ends, and are connected with an alternating current power source. A terminal c and a terminal d are alternating current output ends, and are connected with an alternating current load. When the amplitude of the voltage of the alternating current power source falls below or rises above the normal range, the bilateral switch is cut off. According to the dynamic voltage correcting device, the voltage of the alternating current input ends and the output voltage of the second convertor are filtered by the LC filter after superposition is conducted on the voltage of the alternating current input ends and the output voltage of the second convertor, so that the voltage amplitude of alternating current output ends is corrected to the normal range. When short-circuit malfunction occurs in the load, a load short circuit current is limited by the device, so that the alternating current power source is free from the effect of the load short circuit. Due to the fact that the dynamic voltage correcting device is not provided with a transformer and an external power supply, the dynamic voltage correcting device has the advantages of being small in volume, light in weight, simple in structure and high in output waveform quality.

Description

technical field [0001] The invention relates to a dynamic voltage correction device, which belongs to the field of power quality control. Background technique [0002] In the AC grid power supply mode, the voltage of the common connection point will inevitably have a voltage amplitude sag or a swell disturbance, and the load sensitive to voltage usually needs to be connected in series with a voltage correction device of the corresponding power level at the access end to correct the supply voltage to normal voltage range. The traditional Dynamic Voltage Restorer (Dynamic Voltage Restorer) used to correct the voltage uses a series transformer to string the compensated voltage into the power supply terminal to stabilize the power supply voltage. In order to reduce the volume and weight of the device, the transformerless dynamic voltage restorer directly connects the output capacitance of the compensation converter to the power supply terminal, but this solution still requires ...

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Problems solved by technology

The equipment has high working reliability, but has the disadvantage of large equipment volume and weight

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