Numerical control power supply overvoltage protection circuit

Abstract

The invention relates to a numerical control power supply overvoltage protection circuit which comprises a soft start circuit, a rectifier circuit, a filter circuit and an auxiliary power supply and a monitoring circuit; AC is input to the rectifier circuit through the soft start circuit to be rectified and is filtered by the filter circuit, DC is input to the auxiliary power supply; the auxiliary power supply supplies DC voltage to the monitoring circuit; the monitoring circuit detects the AC voltage and / or bus voltage of a numerical control power supply and generates an overvoltage protection signal; the numerical control power supply overvoltage circuit also comprises an overvoltage protection circuit; and the overvoltage protection circuit is used to receive the overvoltage protectionsignal from the monitoring circuit and / or obtains bus voltage from a bus, and controls the soft start circuit according to the overvoltage protection signal of the monitoring circuit and / or the bus voltage. The numerical control power supply overvoltage protection circuit of the embodiment of the invention does not need any external power supply, has simple design, and can quickly protect under the circumstance that quite a long time is required for obtaining the protection of a digital controller.

Description

technical field [0001] The invention relates to an overvoltage protection circuit, more specifically, to an overvoltage protection circuit for a numerically controlled power supply. Background technique [0002] AC-DC switching power supply often encounters large-scale fluctuations in grid voltage in practical application environments. In the middle and high power levels, the front stage of the switching power supply requires the design of an active power factor correction (PFC) circuit to reduce the pollution of the input current harmonics to the grid. The PFC bus voltage of different power supplies may be designed differently, but for a specific power supply, the bus voltage should generally not exceed the allowable withstand voltage of the PFC electrolytic capacitor. If the AC voltage is higher than the input overvoltage protection point of the power supply, the rectified bus voltage may exceed the withstand voltage value of the electrolytic capacitor, causing capacitors...

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is to provide an overvoltage protection circuit that does not require an external power supply and has a simple design in view of the defects of the prior art that the overvoltage protection circuit of the numerical control power supply is complex in design, has many devices, occupies a large area, and requires an external power supply. CNC power supply overvoltage protection circuit

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