Potential design of switching power supply?

乱世煮酒论天下

Potential design of switching power supply? [Copy link]

 

The switching power supply on the inverter supplies power to the entire circuit board. The gnd of the switching power supply is the total ground terminal on the low-voltage side. I used a multimeter to measure the voltage between the positive bus and gnd and the negative bus and gnd, and they are the same. How is the ground of the switching power supply set to be exactly the midpoint between the positive and negative bus bars?

maychang

[How to set the ground of the switching power supply to be exactly the midpoint between the positive and negative busbars? ]

Because [gnd of the switching power supply is the common ground terminal on the low voltage side].

乱世煮酒论天下

maychang posted on 2024-5-22 17:23 [How to set the ground of the switching power supply to be exactly the midpoint between the positive and negative busbars? ] Because [the gnd of the switching power supply is the total ground terminal on the low voltage side].

This seems to have no connection. GND is the common ground terminal on the low voltage side, but it is not necessarily at the midpoint of the positive and negative busbars.

maychang

乱世煮酒论天下 posted on 2024-5-22 17:28 This seems to have no connection. GND is the total ground terminal on the low-voltage side, but it is not necessarily at the midpoint of the positive and negative busbars.

[The total ground terminal on the low-voltage side] should be connected to the earth, and the midpoint of the positive and negative busbars should be at the same potential as the earth, because your positive and negative busbars are rectified from three-phase AC.

乱世煮酒论天下

maychang posted on 2024-5-22 17:32 [The total ground terminal on the low-voltage side] should be connected to the earth, and the midpoint of the positive and negative busbars should be at the same potential as the earth, because your positive and negative busbars are from the three-phase AC rectification...

The ground on the low-voltage side is connected to PE through a resistor and capacitor in parallel, and PE is connected to the ground. However, the resistance of this resistor and capacitor grounding is generally very large, with a minimum resistance of about 100K. How is gnd pulled to the same potential as PE?

And I haven't measured whether the voltage between positive and negative gnd is equal when PE is not connected to the ground? I must measure it when I have time.

okhxyyo

乱世煮酒论天下 posted on 2024-5-22 17:28 This seems to have no connection. GND is the total ground terminal on the low-voltage side, but it is not necessarily at the midpoint of the positive and negative busbars.

Not necessarily, but it is likely. Generally, it is set this way unless there are special requirements.

乱世煮酒论天下

okhxyyo posted on 2024-5-23 10:26 Not necessarily, but it is likely that it is. Generally, if there is no special requirement, it will be set in this way.

So here is the question: why is the gnd on the low voltage side located in the middle of the positive and negative busbars?

maychang

Luan Shi Zhu Jiu Lun Tian Xia published on 2024-5-23 10:35 So here is a question, why can the GND on the low voltage side be in the middle of the positive and negative busbars?

[So here's the question, why can the gnd on the low voltage side be in the middle of the positive and negative busbars? ]

You haven't figured out where the voltage on the positive and negative bus bars comes from, and where the GND on the low-voltage side comes from.

beyond_笑谈

The auxiliary power supply in the inverter is generally a flyback topology with a center tap. The voltage values of the positive and negative voltage outputs are designed according to the windings of the transformer and can be the same or different.