EMC circuit grounding structure of frequency converter

Abstract

The utility model discloses an EMC circuit grounding structure of a frequency converter. Comprising an EMC safety circuit over-ground over-current copper bar, an EMC safety circuit over-ground short-circuit copper bar, a VDR piezoresistor over-ground short-circuit copper bar, an EMC safety circuit over-ground short-circuit screw, a VDR piezoresistor over-ground short-circuit screw, an EMC insulating column, a piezoresistor over-ground short-circuit copper bar, an EMC PCB, a VDR piezoresistor over-current copper bar and a piezoresistor. The metal plate support and the metal plate case are fixed together through screws to be connected with the ground in a grounded mode, the EMC safety circuit ground short circuit copper bar and the VDR voltage dependent resistor ground short circuit copper bar are fixed to the metal plate support through EMC short circuit screws and VDR voltage dependent resistor short circuit screws respectively, the EMC insulating column and the voltage dependent resistor insulating column are fixed to the metal plate support, and the EMC safety circuit ground short circuit copper bar and the VDR voltage dependent resistor ground short circuit copper bar are fixed to the metal plate support through the VDR voltage dependent resistor short circuit screws respectively. The safety circuit over-ground over-current copper bar is connected with the EMC PCB and is fixed on the EMC insulation column. The VDR voltage dependent resistor over-current copper bar is connected with the voltage dependent resistor and is fixed on the voltage dependent insulation column.

Description

Technical Field

[0001] The utility model relates to a grounding structure of an EMC circuit of a frequency converter. Background Art

[0002] In order to better meet the market requirements for the electromagnetic compatibility of products, an electromagnetic compatibility filter is built into the frequency converter. The electromagnetic compatibility filter discharges the common-mode surge noise to the ground through a varistor (hereinafter referred to as VDR), and discharges the common-mode high-frequency noise to the ground through a Y capacitor (hereinafter referred to as EMC). However, the power grid systems in different countries and regions are different at present. Some countries and regions have a symmetric grounding system for the power grid, and some countries and regions have an asymmetric grounding system for the power grid. When the frequency converter is used in an asymmetric grounding power grid system, the Y capacitor and the varistor of the electromagnetic compatibility filter in the frequency converter are connected to the ground potential. When the potential exceeds the voltage range allowed by the Y capacitor and the varistor, it will cause permanent damage to the electromagnetic compatibility filter inside the frequency converter. Summary of the Invention

[0003] The purpose of the utility model is to provide a grounding structure of an EMC circuit of a frequency converter. To achieve the above purpose, the utility model provides the following technical solutions:

[0004] A grounding structure of an EMC circuit of a frequency converter includes an overcurrent copper bar for the EMC safety circuit to the ground, a short-circuit copper bar for the EMC safety circuit to the ground, a short-circuit copper bar for the VDR varistor to the ground, a screw for short-circuiting the EMC safety circuit to the ground, a screw for short-circuiting the VDR varistor to the ground, an EMC insulating column, a short-circuit copper bar for the varistor to the ground, an EMC PCB board, an overcurrent copper bar for the VDR varistor, and a varistor; the sheet metal bracket is fixed to the sheet metal chassis with screws for grounding connection to realize connection to the ground. The short-circuit copper bar for the EMC safety circuit to the ground and the short-circuit copper bar for the VDR varistor to the ground are respectively fixed on the sheet metal bracket with EMC short-circuit screws and VDR varistor short-circuit screws. The EMC insulating column and the varistor insulating column are respectively fixed on the sheet metal bracket. The overcurrent copper bar for the safety circuit to the ground is connected to the EMC PCB board and fixed on the EMC insulating column. The overcurrent copper bar for the VDR varistor is connected to the varistor and fixed on the varistor insulating column.

[0005] Further, the insulating column is made of nylon material.

[0006] The beneficial effect of the utility model is that the grounding conductors for connecting EMC and VDR are made of copper bars, and the withstand voltage value and current-carrying capacity are greatly improved, which can play an excellent protective role when the EMC of a high-power frequency converter is connected to the ground and needs to cope with lightning strikes, abnormal voltages, and currents. When the connection between EMC and VDR to the ground is in an open state, the short-circuit copper bar can also be fixed to avoid disconnection failure caused by vibration or loss of parts. Description of the Drawings

[0007] Figure 1 Schematic diagram of the main components of the EMC and VDR structures of the present utility model;

[0008] Figure 2 Internal schematic diagram of the disconnection of the EMC and VDR safety circuits from the ground of the present utility model;

[0009] Figure 3 Dynamic schematic diagram of the copper strip of the EMC and VDR safety circuits connected to the ground of the present utility model;

[0010] Figure 4 Internal schematic diagram of the connection of the EMC and VDR safety circuits to the ground of the present utility model;

[0011] Figure 5 External schematic diagram of the connection of the EMC and VDR safety circuits to the ground of the present utility model;

[0012] Figure 6 Operation instruction label diagram for the connection of the EMC and VDR safety circuits to the ground of the present utility model; Specific implementation manner

[0013] As Figures 1 to 6 shown, the present utility model relates to an EMC circuit grounding structure of an inverter, including an overcurrent copper strip 1-1 for the EMC safety circuit connected to the ground, a short-circuit copper strip 1-2-1 for the EMC safety circuit connected to the ground, a short-circuit copper strip 1-2-2 for the VDR varistor connected to the ground, a screw 1-3-1 for short-circuiting the EMC safety circuit connected to the ground, a screw 1-3-2 for short-circuiting the VDR varistor connected to the ground, an EMC insulating column 1-4-1, a varistor insulating column 1-4-2, an EMC PCB board 1-5, an overcurrent copper strip 1-6 for the VDR varistor, and a varistor 1-7; the sheet metal bracket 2-1 and the sheet metal chassis screw 2-2 are fixed together for grounding connection to achieve connection to the ground. The short-circuit copper strip 1-2-1 for the EMC safety circuit connected to the ground and the short-circuit copper strip 1-2-2 for the VDR varistor connected to the ground are respectively fixed on the sheet metal bracket 2-1 using the EMC short-circuit screw 1-3-1 and the VDR varistor short-circuit screw 1-3-2. The EMC insulating column 1-4-1 and the varistor insulating column 1-4-2 are respectively fixed on the sheet metal bracket 2-1. The overcurrent copper strip 1-1 for the safety circuit connected to the ground is connected to the EMC PCB board 1-5 and fixed on the EMC insulating column 1-4-1. The overcurrent copper strip 1-6 for the VDR varistor is connected to the varistor 1-7 and fixed on the varistor insulating column 1-4-2.

[0014] When the short-circuit copper strip 1-2-1 for the EMC safety circuit and the short-circuit copper strip 1-2-2 for the VDR varistor connected to the ground need to be connected and conducted, it is necessary to refer to Figure 3"Internal Dynamic Schematic Diagram of the EMC and VDR Safety Capacitor's Ground Copper Strips" Rotate the EMC safety circuit's ground shorting copper strip 1-2-1 and the VDR varistor's ground shorting copper strip 1-2-2 in the direction indicated by the arrow, and respectively overlap them on the safety circuit's ground overcurrent copper strips 1-1 and 1-6 (the VDR varistor's overcurrent copper strip), and use the EMC shorting screw 1-3-1 and the VDR varistor shorting screw 1-3-2 to tighten and fix them, so as to achieve the connection of the EMC and VDR safety circuits to the ground.

[0015] For better explaining the implementation manner of the present invention, the Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 shown operation steps are presented separately. However, the above-mentioned steps can be directly operated under the state of the Figure 5 shown 3-1 metal shell buckling. Refer to Figure 5 . Among them, for the metal shell 3-1 of the frequency converter, under the buckled state, the operation methods of connecting and disconnecting the EMC and VDR safety circuits to the ground are respectively referred to Figure 6 , the EMC safety circuit's ground connection operation instruction label and the VDR safety circuit's ground connection operation instruction label.

[0016] As mentioned above, it is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. The protection scope of the present invention should be subject to the protection scope of the claims. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art, without departing from the technical solution scope of the present invention, can make some changes or modifications to it as equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An EMC circuit grounding structure of a frequency converter, comprising an EMC safety circuit overcurrent copper bar to ground, an EMC safety circuit short-circuited copper bar to ground, a VDR varistor short-circuited copper bar to ground, an EMC safety circuit short-circuited screw to ground, a VDR varistor short-circuited screw to ground, an EMC insulating column, a varistor short-circuited copper bar to ground, an EMC PCB board, a VDR varistor overcurrent copper bar, and a varistor; a sheet metal bracket is fixed together with a sheet metal chassis screw for grounding connection to achieve connection with the earth, the EMC safety circuit short-circuited copper bar to ground and the VDR varistor short-circuited copper bar to ground are fixed to the sheet metal bracket using EMC shorting screws and VDR varistor shorting screws respectively, the EMC insulating column and the varistor insulating column are fixed to the sheet metal bracket respectively, the safety circuit overcurrent copper bar to ground is connected to the EMC PCB board and fixed to the EMC insulating column, and the VDR varistor overcurrent copper bar is connected to the varistor and fixed to the varistor insulating column.

2. The EMC circuit grounding structure of a frequency converter according to claim 1, characterized in that: The insulating column is made of nylon material.

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