Filter capacitor charging circuit, monitoring system and monitoring processing method

Abstract

The invention relates to a filter capacitor charging circuit, a monitoring system and a monitoring processing method, and belongs to the technical field of power supply filtering. The charging circuitcomprises: a filter capacitor module which is provided with at least one charging input end; at least one controllable resistor, wherein each charging input end of the filter capacitor module is correspondingly connected with a controllable resistor in series; and a controllable switch module which is provided with at least one switch unit, wherein each controllable resistor is correspondingly connected with the switch unit in parallel. According to the application, the problem of charging current impact of the filter capacitor during power supply filtering of the filter is solved, and the filtering effect of the filter is ensured.

Description

technical field [0001] The application belongs to the technical field of power supply filtering, and in particular relates to a filter capacitor charging circuit, a monitoring system and a monitoring processing method. Background technique [0002] At present, in the fields of high-power inverters, converters, frequency converters, etc., in order to reduce the high-frequency harmonic interference generated by nonlinear loads on the AC grid side, designers are gradually using LC and LCL filters in the main circuit, but Regardless of whether it is an LC filter or an LCL filter, the pre-charging of the capacitor when it starts is an important part of equipment safety protection. In order to reduce the instantaneous surge current of capacitor charging, protect the safety of the equipment, and weaken the harmonics of the equipment to the power grid Interference, now generally used as a high-power resistor in series with a filter capacitor, please refer to figure 1 , figure 1 It...

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Problems solved by technology

However, in this way, due to the existence of resistance, the filtering effect of the filter is weakened

Another designer chooses the right time to short-circuit the resistance through the contactor after starting up, please refer to figure 2 , figure 2 It is a schematic diagram of the electrical structure of an LCL filter in the related art shown according to another exemplary embodiment. The resistor is short-circuited through a contactor, but in this way, if the resistance value of the resistor is too small, the inrush current cannot be effectively weakened, and if The resistance is too large, and there is also a phase difference between the capacitor voltage and the grid side voltage before and after the short circuit of the resistance, resulting in an inrush current, which cannot effectively solve the problem of charging current inrush

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