Low-voltage small-power ACDC power supply with pre-charging device

Abstract

The invention relates to a low-voltage small-power ACDC power supply with a pre-charging device, an auxiliary power supply of the ACDC power supply is provided with a transformer, and the pre-charging device comprises a secondary winding N4 on the transformer and a one-way conduction element connected in series to the dotted terminal side of the secondary winding N4. The dotted terminal of the secondary winding N4 is connected to a direct-current positive bus of the ACDC power supply through a one-way conduction element, a direct-current negative bus is connected with the other end of the secondary winding N4, and the conduction direction of the one-way conduction element is that the dotted terminal flows to the positive bus. The size of the pre-charging loop can be reduced, the cost of the pre-charging loop is reduced, the pre-charging efficiency is improved, and the system reliability is improved.

Description

technical field [0001] The invention relates to the field of power supplies, in particular to a low-voltage low-power ACDC power supply with a precharging device. Background technique [0002] The low-voltage low-power ACDC bidirectional isolated power supply module is basically composed of AC / DC circuit, DC / DC circuit, voltage and current detection circuit, switch tube drive circuit, control circuit, cooling fan and auxiliary power supply. Power supply (DC) for circuit, fan and control circuit, such as control circuit needs auxiliary power supply to provide 12V power supply, 24V power supply to fan, etc. The low-voltage low-power ACDC bidirectional isolated power supply module can not only convert AC220V alternating current into direct current to charge the battery (battery voltage is up to 30V), but also invert the battery voltage to AC220V to supply power to AC equipment. The principle of this bidirectional isolated power supply (ACDC) is generally to rectify the alterna...

AI Technical Summary

Problems solved by technology

With such a complex charging circuit, as long as there is a problem in one place, the entire power system will not be able to operate normally

[0015] 2. The pre-charging circuit is very bulky, and the optical current-limiting power supply or soft starter takes up a lot of space

[0019] If the resistance current limiting charging method is used, although it does not affect the power grid, it is an energy-consuming charging method. The energy charged to the bus capacitor is less than the energy consumed by the pre-charging circuit (resistor, switch), and a lot of energy is in the resistor. is consumed

Also, the charging efficiency is low. As the voltage of the pre-charged capacitor increases, the charging current becomes smaller and smaller, and it takes a long time to complete the pre-charging work.

In addition, the heat emitted by the circuit during the pre-charging process will cause the internal temperature of the device to rise, causing system instability, etc.

[0020] 4. The cost of the pre-charging circuit is too high

[0021] This precharge circuit is costly due to its complexity

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