CN-115275940-B - Switch power supply protection circuit, control method, switch power supply and electrical equipment

CN115275940BCN 115275940 BCN115275940 BCN 115275940BCN-115275940-B

Abstract

The application relates to a switching power supply protection circuit, a control method, a switching power supply and electrical equipment, and belongs to the technical field of switching power supply protection circuits. In the application, the switch circuit module is arranged that one end of a bus current on-off control side of the switch circuit module is connected with a direct current bus, the other end of the bus current on-off control side of the switch circuit module is connected with a bus capacitor and a DC/DC conversion circuit of a switch power supply, and when the bus current on-off control side of the switch circuit module is disconnected, an open circuit is formed between the direct current bus and the bus capacitor and the DC/DC conversion circuit respectively. Under the setting, when the controller judges that the bus voltage exceeds the upper limit value of the range of the preset normal voltage interval according to the sampling voltage, the bus current on-off control side of the switch circuit module is controlled to be disconnected, and overvoltage direct current is not transmitted to the bus capacitor and the DC/DC conversion circuit of the switch power supply, so that overvoltage protection is realized on the bus capacitor and the DC/DC conversion circuit of the switch power supply.

Inventors

Wang Jinweng
FANG LIN
JIN GUOHUA
YE HUANTAO
HU GUANHUA

Assignees

珠海格力电器股份有限公司

Dates

Publication Date: 20260505
Application Date: 20220721

Claims (14)

1. A switching power supply protection circuit, comprising: The voltage sampling circuit module, the switch circuit module and the controller; The voltage sampling circuit module is used for obtaining a sampling voltage of a direct current bus of the switching power supply and sending the sampling voltage to the controller, wherein the sampling voltage can represent the bus voltage of the direct current bus; The output end of the controller is connected with the signal input end of the switch circuit module; One end of a bus current on-off control side of the switch circuit module is connected with the direct current bus, the other end of the bus current on-off control side of the switch circuit module is connected with a bus capacitor and a DC/DC conversion circuit of the switch power supply, when the bus current on-off control side of the switch circuit module is disconnected, an open circuit is formed between the direct current bus and the bus capacitor and the DC/DC conversion circuit respectively, and when the bus current on-off control side of the switch circuit module is conducted, a passage is formed between the direct current bus and the bus capacitor and the DC/DC conversion circuit respectively; The switching circuit module comprises an electronic switching tube and a relay, wherein the driving end of the electronic switching tube is used as a signal input end of the switching circuit module and is connected with the output end of the controller, and the on-off side of the electronic switching tube is connected with the coil side of the relay; and the relay on-off side is used as a bus current on-off control side of the switch circuit module, one end of the relay on-off side is connected with the direct current bus, and the other end of the relay on-off side is connected with the bus capacitor and the DC/DC conversion circuit.
2. The switching power supply protection circuit according to claim 1, wherein the bus current on-off control side of the switching circuit module is normally off.
3. The switching power supply protection circuit according to claim 1, wherein the electronic switching tube is a triode or a MOS tube.
4. The switching power supply protection circuit of claim 1 wherein said switching circuit module further comprises: The flywheel diode and the capacitor are respectively connected with the coil side of the relay in parallel.
5. The switching power supply protection circuit according to claim 1, wherein the switching circuit module further comprises a protection resistor connected in series between an output terminal of the controller and a signal input terminal of the switching circuit module.
6. The switching power supply protection circuit according to claim 1, wherein the sampling circuit comprises two voltage dividing resistors, the two voltage dividing resistors form a series circuit, one end of the series circuit is connected with a direct current bus of the switching power supply, the other end of the series circuit is grounded, and a sampling signal input end of the controller is connected to a line between the two voltage dividing resistors.
7. The switching power supply protection circuit of claim 1 further comprising a display module coupled to the controller.
8. A switching power supply protection circuit control method, characterized in that the method is applied to the controller of the switching power supply protection circuit according to any one of claims 1 to 7, the method comprising: Receiving sampling voltage sent by a voltage sampling circuit module, wherein the sampling voltage can represent bus voltage of a direct current bus; And judging whether the bus voltage exceeds the upper limit value of a preset normal voltage interval range according to the sampling voltage, and if so, sending a first control signal to a switch circuit module to disconnect the bus current on-off control side of the switch circuit module so as to enable the direct current bus to be disconnected with a bus capacitor and a DC/DC conversion circuit of a switch power supply respectively.
9. The method of claim 8, wherein the method further comprises: And when the bus voltage is judged to be in the normal voltage interval range according to the sampling voltage, a second control signal is sent to the switch circuit module, so that the bus current on-off control side of the switch circuit module is conducted, and a passage is formed between the direct current bus and a bus capacitor and a DC/DC conversion circuit of the switch power supply respectively.
10. The method of claim 8, wherein the method further comprises: And when the bus voltage is judged to be lower than the lower limit value of the normal voltage interval range according to the sampling voltage, sending the first control signal to the switch circuit module, so that the bus current on-off control side of the switch circuit module is disconnected, and the direct current bus is disconnected with a bus capacitor of the switch power supply and the DC/DC conversion circuit respectively.
11. The method according to any one of claims 8-10, further comprising: when the bus voltage is judged not to exceed the normal voltage interval range, controlling a display module to display first display information, wherein the first display information is used for indicating that the input voltage of the switching power supply is normal; When the bus voltage is judged to exceed the upper limit of the normal voltage interval range, the display module is controlled to display second display information, wherein the second display information is used for indicating the overvoltage of the input voltage of the switching power supply; and when the bus voltage is judged to exceed the lower limit of the normal voltage interval range, controlling the display module to display third display information, wherein the third display information is used for indicating the input voltage undervoltage of the switching power supply.
12. A switching power supply comprising a switching power supply protection circuit according to any one of claims 1 to 7, and a switching power supply protection circuit control method according to any one of claims 8 to 11.
13. An electrical device comprising the switching power supply of claim 12.
14. The electrical device of claim 13, wherein the electrical device comprises an air conditioner.

Description

Switch power supply protection circuit, control method, switch power supply and electrical equipment Technical Field The application belongs to the technical field of switching power supply protection circuits, and particularly relates to a switching power supply protection circuit, a control method, a switching power supply and electrical equipment. Background The switching power supply is widely applied to electrical equipment, and normally, the switching power supply is internally provided with an overvoltage and undervoltage protection circuit so as to play a role in overvoltage or undervoltage protection when overvoltage or undervoltage occurs. Referring to fig. 1, fig. 1 is a schematic diagram of a related art switching power supply circuit according to an embodiment, and fig. 1 shows that a control end of a controller U1 is connected to a DC/DC conversion circuit to control on/off of the DC/DC conversion circuit. Wherein DC represents direct current, and the DC/DC conversion circuit is used for converting input A-volt direct current into B-volt direct current. The controller U1 obtains a DC bus sampling voltage through a voltage sampling circuit (formed by R1, R2 and Rcs in fig. 1), and controls the DC/DC conversion circuit to be turned off when an overvoltage or an undervoltage is determined according to the DC bus sampling voltage. In the switching power supply circuit shown in fig. 1, since the control terminal of the controller U1 is connected to the DC/DC conversion circuit, for the bus capacitor C1 located on the input side of the DC/DC conversion circuit and some of the electronic components in the DC/DC conversion circuit, if the DC bus in the switching power supply circuit is over-voltage, some of the electronic components in the bus capacitor C1 and the DC/DC conversion circuit actually receive over-voltage direct current, and the over-voltage direct current may cause some of the electronic components in the bus capacitor C1 and the DC/DC conversion circuit to break down, thereby causing the switching power supply itself to be damaged. Disclosure of Invention Therefore, the application provides the switch power supply protection circuit, the control method, the switch power supply and the electrical equipment, which are helpful to solve the problem that if the direct current of the direct current bus is over-voltage under the condition that the protection circuit of the switch power supply is connected with the DC/DC conversion circuit, the bus capacitance of the switch power supply and some electronic elements in the DC/DC conversion circuit are possibly broken down. In order to achieve the above purpose, the application adopts the following technical scheme: in a first aspect, the present application provides a switching power supply protection circuit comprising: The voltage sampling circuit module, the switch circuit module and the controller; The voltage sampling circuit module is used for obtaining a sampling voltage of a direct current bus of the switching power supply and sending the sampling voltage to the controller, wherein the sampling voltage can represent the bus voltage of the direct current bus; The output end of the controller is connected with the signal input end of the switch circuit module; The direct current bus is connected to one end of a bus current on-off control side of the switch circuit module, the other end of the bus current on-off control side of the switch circuit module is connected to a bus capacitor and a DC/DC conversion circuit of the switch power supply, when the bus current on-off control side of the switch circuit module is disconnected, an open circuit is formed between the direct current bus and the bus capacitor and the DC/DC conversion circuit respectively, and when the bus current on-off control side of the switch circuit module is conducted, a passage is formed between the direct current bus and the bus capacitor and the DC/DC conversion circuit respectively. Further, the bus current on-off control side of the switch circuit module is normally off. The switching circuit module comprises an electronic switching tube and a relay, wherein the driving end of the electronic switching tube is used as a signal input end of the switching circuit module and is connected with the output end of the controller, and the on-off side of the electronic switching tube is connected with the coil side of the relay; and the relay on-off side is used as a bus current on-off control side of the switch circuit module, one end of the relay on-off side is connected with the direct current bus, and the other end of the relay on-off side is connected with the bus capacitor and the DC/DC conversion circuit. Further, the electronic switch tube adopts a triode or a MOS tube. Further, the switching circuit module further includes: The flywheel diode and the capacitor are respectively connected with the coil side of the relay in parallel. Further, the switch circuit module al