Power supply switching circuit and auxiliary power supply system

Abstract

The utility model provides a power supply switching circuit and an auxiliary power supply system. The power supply switching circuit comprises a driving module, a switch module and an output module, the driving module is connected to the first power supply and the switch module; the switch module is connected to the second power supply and is connected with the output module; the output module is connected to a first power supply and a load; the driving module outputs a first electric signal to the switch module when the first power supply is electrified, and outputs a second electric signal to the switch module when the first power supply is not electrified and the second power supply is electrified; the switch module disconnects the second power supply from the output module when receiving the first electric signal, so that the second power supply stops supplying power to the load; and the switch module conducts the second power supply and the output module when receiving the second electric signal, so that the second power supply supplies power to the load. Therefore, the condition of competitive loading of the power supply can be reduced, the power supply voltage is kept stable, and the reliability of the auxiliary power supply system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply circuits, and in particular to a power supply switching circuit and an auxiliary power supply system. Background Art

[0002] In energy storage inverters, the auxiliary power system, often referred to as the "auxiliary power system," is essential for the inverter's normal operation. Typically, two auxiliary power sources are designed to power the inverter: one is an AC auxiliary power source that draws power from the AC (alternating current) side, and the other is a DC auxiliary power source that draws power from the DC (direct current) bus. These two auxiliary power sources ensure that the inverter's communication circuits remain powered when there's no input from the photovoltaic panels or energy storage batteries, allowing for standby data monitoring.

[0003] In the prior art, both AC and DC auxiliary sources employ a flyback multi-output topology. When both the AC and DC auxiliary sources are functioning normally, the auxiliary source with the higher output voltage typically powers the communication circuit. However, flyback multi-output circuits often suffer from cross-regulation issues. This means that when other loads powered by the AC or DC auxiliary source change, the output voltage of the AC or DC auxiliary source changes, causing the two auxiliary sources to compete for load. This results in unstable voltage supplying the communication circuit, causing the voltage to switch back and forth between the output voltages of the AC or DC auxiliary source. Furthermore, the auxiliary source's operating state also fluctuates between loads, significantly reducing the reliability of the auxiliary source system. Utility Model Content

[0004] In view of the above, it is necessary to provide a power switching circuit and an auxiliary power system that can reduce the situation of power competition and load, keep the power supply voltage stable, and thus improve the reliability of the auxiliary power system.

[0005] In a first aspect, the present application provides a power switching circuit, comprising: a driving module, a switch module and an output module; the input end of the driving module is connected to the output end of the first power supply, and the output end of the driving module is connected to one input end of the switch module; the other input end of the switch module is connected to the output end of the second power supply, and the output end of the switch module is connected to the first input end of the output module; the second input end of the output module is connected to the output end of the first power supply, and is used to obtain electrical energy from the first power supply when the first power supply is energized, and the output end of the output module is connected to a load; the driving module is used to output a first electrical signal to the switch module when the first power supply is energized, and to output a second electrical signal to the switch module when the first power supply is not energized and the second power supply is energized; the switch module is used to disconnect the second power supply from the output module when receiving the first electrical signal, so that the second power supply stops supplying power to the load; and the switch module is used to connect the second power supply to the output module when receiving the second electrical signal, so that the second power supply supplies power to the load.

[0006] In some embodiments, the driving module includes a three-terminal regulator, the reference terminal of the three-terminal regulator is connected to the output terminal of the first power supply, the cathode terminal of the three-terminal regulator is connected to an input terminal of the switching module, and the anode terminal of the three-terminal regulator is grounded; when the first power supply is energized, the cathode terminal of the three-terminal regulator generates a first electrical signal; when the first power supply is not energized, the cathode terminal of the three-terminal regulator generates a second electrical signal.

[0007] In some embodiments, the driving module further includes a voltage dividing unit connected between a reference terminal of the three-terminal regulator and an output terminal of the first power supply.

[0008] In some embodiments, the switch module includes a first switch tube and a second switch tube, the first end of the first switch tube is connected to the output end of the driving module, the second end of the first switch tube is connected to the zero potential point, the third end of the first switch tube is connected to the first end of the second switch tube, the second end of the second switch tube is connected to the output end of the second power supply, and the third end of the second switch tube is connected to the input end of the output module; the first switch tube is turned on when receiving a first electrical signal and outputs a first level to the second switch tube, and the second switch tube is turned on when receiving the first level; the first switch tube is turned off when receiving a second electrical signal and outputs a second level to the second switch tube, and the second switch tube is turned off when receiving the second level.

[0009] In some embodiments, the switch module includes a current limiting unit, the second end of the second switch tube is connected to the output end of the driving module through the current limiting unit, and the output end of the second power supply is connected between the current limiting unit and the second end of the second switch tube.

[0010] In some embodiments, the switch module includes a driving voltage dividing unit connected between the output terminal of the driving module and the first terminal of the first switch tube.

[0011] In some embodiments, the output module includes a first protection element and a second protection element. The first input end of the output module is connected to the output end of the switch module through the first protection element. The second input end of the output module is connected to the output end of the first power supply through the second protection element.

[0012] In some embodiments, the first protection element and the second protection element are diodes.

[0013] The second aspect of the present application provides an auxiliary power supply system, comprising: a first power supply, a second power supply and a power switching circuit; the power switching circuit comprises: a driving module, a switch module and an output module; the input end of the driving module is connected to the output end of the first power supply, and the output end of the driving module is connected to one input end of the switch module; the other input end of the switch module is connected to the output end of the second power supply, and the output end of the switch module is connected to the first input end of the output module; the second input end of the output module is connected to the output end of the first power supply and obtains electrical energy from the first power supply when the first power supply is energized, and the output end of the output module is connected to the load; the driving module is used to output a first electrical signal to the switch module when the first power supply is energized, and to output a second electrical signal to the switch module when the first power supply is not energized and the second power supply is energized; the switch module is used to disconnect the second power supply from the output module when receiving the first electrical signal, so that the second power supply stops supplying power to the load; and the switch module is used to connect the second power supply to the output module when receiving the second electrical signal, so that the second power supply supplies power to the load.

[0014] In some embodiments, the first power source is an AC-to-DC power source, the second power source is a DC-to-DC power source, and the load is an inverter.

[0015] Compared with the prior art, this application has at least the following advantages:

[0016] 1. In the power switching circuit and auxiliary power supply system of the present application, the driver module can output a first electrical signal to the switch module when the first power supply is energized. The switch module can disconnect the second power supply from the output module upon receiving the first electrical signal so that the second power supply stops supplying power to the load. In this case, even if both the first power supply and the second power supply are energized, and other loads of the first power supply and the second power supply jump, causing the output voltages of the first power supply and the second power supply to also jump, the driver module and the switch module can force the first power supply to be selected to supply power to the load, thereby reducing the situation where power supplies compete for load and keeping the supply voltage stable. In this way, the reliability of the auxiliary power supply system can be improved.

[0017] 2. In addition, the driver module can also output a second electrical signal to the switch module when the first power supply is de-energized and the second power supply is energized. Upon receiving the second electrical signal, the switch module can connect the second power supply to the output module, allowing the second power supply to supply power to the load. Simultaneously, the second input terminal of the output module is connected to the output terminal of the first power supply. In this case, when one of the first and second power supplies is energized, the energized auxiliary power source is selected to supply power to the load. If the first power supply is energized and the second power supply is de-energized, the load can obtain power directly from the first power supply via the output module. If the first power supply is de-energized and the second power supply is energized, the load can obtain power from the second power supply via the switch module and the output module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the working principle of the auxiliary source switching circuit in the prior art.

[0019] Figure 2 It is a structural diagram of the auxiliary power supply system of an embodiment of the present application.

[0020] Figure 3 It is a structural diagram of an auxiliary power supply system of another embodiment of the present application.

[0021] Figure 4 This is a circuit diagram of the auxiliary power supply system of an embodiment of the present application.

[0022] Description of main component symbols:

[0023] Auxiliary power system 100

[0024] First power supply 1

[0025] Second power supply 2

[0026] Power switching circuit 3

[0027] Driver module 31

[0028] Three-terminal voltage regulator 311

[0029] Switch module 32

[0030] Output module 33

[0031] Output interface 331

[0032] Load 200

[0033] Auxiliary source switching circuit 4

[0034] AC auxiliary source 5

[0035] DC auxiliary source 6

[0036] The following specific implementation methods will further illustrate this application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0037] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, unless otherwise specified in this application, " / " means or. For example, A / B can mean A or B. "And / or" in this application is merely a way to describe the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. "At least one" means one or more. "Multiple" means two or more than two. For example, at least one of a, b or c can mean: a, b, c, a and b, a and c, b and c, a, b and c.

[0039] It should also be noted that the terms "first" and "second" in the description, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0040] In energy storage inverters, the auxiliary power system, often referred to as the "auxiliary power system," is essential for the inverter's normal operation. Typically, two auxiliary power sources are designed to power the inverter: one is an AC auxiliary power source that draws power from the AC (alternating current) side, and the other is a DC auxiliary power source that draws power from the DC (direct current) bus. These two auxiliary power sources ensure that the inverter's communication circuits remain powered when there's no input from the photovoltaic panels or energy storage batteries, allowing for standby data monitoring.

[0041] Figure 1 FIG. 4 is a schematic diagram of the working principle of the auxiliary source switching circuit 4 in the prior art. Figure 1As shown, in the prior art, both the AC auxiliary source 5 and the DC auxiliary source 6 employ a flyback multi-output topology. These sources can power different control circuits or communication circuits within the energy storage inverter. For example, the AC auxiliary source 5 can output a voltage of Vac_others or the DC auxiliary source 6 can output a voltage of Vdc_others to power the control circuit. For example, the AC auxiliary source 5 can output a voltage of Vac_com or the DC auxiliary source 6 can output a voltage of Vdc_com to power the communication circuit. However, when both power the communication circuits, selective switching is required via the auxiliary source switching circuit 4. Existing auxiliary source switching circuits 4 typically perform selective switching by comparing the output voltages of the AC auxiliary source 5 and DC auxiliary source 6. Specifically, the auxiliary source switching circuit 4 can ensure that when one of the AC auxiliary source 5 and DC auxiliary source 6 is powered off, the other maintains a normal output voltage of Vcom. Alternatively, when both the AC auxiliary source 5 and DC auxiliary source 6 are powered on, the one with the higher voltage maintains a normal output voltage of Vcom.

[0042] However, multiple flyback outputs often suffer from cross-regulation issues. Specifically, when the AC auxiliary source 5 or DC auxiliary source 6 experiences load changes other than the aforementioned communication circuit, such as when different control circuits in the energy storage inverter change, the Vac_com or Vdc_com voltage changes. This causes the two auxiliary sources to compete for load, making the Vcom voltage unstable and switching back and forth between Vac_com and Vdc_com. Simultaneously, the auxiliary sources also operate in a state of switching loads back and forth. For some variable-frequency flyback auxiliary sources, large-scale load changes can cause their operating frequency to fluctuate significantly, posing a risk of damaging the power devices in the auxiliary source system, thereby significantly reducing the reliability of the auxiliary source system. Therefore, the auxiliary source switching circuit 4 or auxiliary source system in the prior art needs to be improved.

[0043] To this end, embodiments of the present application provide a power switching circuit and an auxiliary power system. Some embodiments will be described below with reference to the accompanying drawings. The following embodiments and features thereof may be combined with one another unless they conflict.

[0044] Figure 2 Schematic diagram of the auxiliary power supply system 100 according to an embodiment of the present application.

[0045] See also Figure 2 The auxiliary power supply system 100 includes a first power supply 1, a second power supply 2, and a power switching circuit 3. The first power supply 1 and the second power supply 2 are connected to the power switching circuit 3, and power is supplied to the load 200 through the power switching circuit 3.

[0046] In an embodiment of the present application, the power switching circuit 3 can enable the second power supply 2 to supply power to the load 200 or stop the second power supply 2 from supplying power to the load 200. For example, when the first power supply 1 is de-energized and the second power supply 2 is energized, the second power supply 2 can be enabled to supply power to the load 200; when both the first power supply 1 and the second power supply 2 are energized, the second power supply 2 can be stopped from supplying power to the load 200. This can reduce the problem of multiple power supplies competing for load power due to a jump in the output voltage of the power supply caused by a jump in the load 200 when selecting a power source by comparing voltages in the prior art, thereby improving the stability and reliability of the auxiliary power supply system 100.

[0047] In some embodiments, the first power supply 1 is an AC-to-DC power supply, that is, the first power supply 1 can draw power from the AC side (such as the power grid) and convert it into DC power that can be used by the load 200 of the embodiment of the present application. The first power supply 1 can also be called an AC auxiliary source.

[0048] In some embodiments, the second power supply 2 is a DC-to-DC power supply, that is, the second power supply 2 can draw power from the DC side (such as a battery or photovoltaic panel) and convert it into DC power that can be used by the load 200 of the embodiment of the present application. The second power supply 2 can also be called a DC auxiliary source.

[0049] In some embodiments, the load 200 may be an inverter. Specifically, the load 200 may include a communication circuit or a control circuit in the inverter.

[0050] Please continue reading Figure 2 The power switching circuit 3 may include: a driving module 31, a switch module 32, and an output module 33. The input end of the driving module 31 is connected to the output end of the first power supply 1, and the output end of the driving module 31 is connected to one input end of the switch module 32; the other input end of the switch module 32 is connected to the output end of the second power supply 2, and the output end of the switch module 32 is connected to the first input end of the output module 33; the second input end of the output module 33 is connected to the output end of the first power supply 1, and the output end of the output module 33 is connected to the load 200.

[0051] In an embodiment of the present application, the driving module 31 is used to output a first electrical signal to the switching module 32 when the first power supply 1 is energized. The switching module 32 is used to disconnect the second power supply 2 from the output module 33 upon receiving the first electrical signal, so that the second power supply 2 stops supplying power to the load 200. In this case, even if the first power supply 1 and the second power supply 2 are both energized, when other loads 200 of the first power supply 1 and the second power supply 2 jump and cause the output voltages of the first power supply 1 and the second power supply 2 to also jump, the driving module 31 and the switching module 32 can force the first power supply 1 to be selected to supply power to the load 200, thereby reducing the situation where power sources compete for load and keeping the supply voltage stable. In this way, the reliability of the auxiliary power supply system 100 can be improved.

[0052] The driver module 31 is further configured to output a second electrical signal to the switch module 32 when the first power supply 1 is de-energized and the second power supply 2 is energized. Upon receiving the second electrical signal, the switch module 32 is configured to connect the second power supply 2 to the output module 33, thereby enabling the second power supply 2 to supply power to the load 200. In this case, when one of the first power supply 1 and the second power supply 2 is energized, the energized auxiliary power source is selected to supply power to the load 200. If the first power supply 1 is de-energized and the second power supply 2 is energized, the load 200 can obtain electrical energy from the second power supply 2 via the switch module 32 and the output module 33.

[0053] The first electrical signal may be a preset voltage value, for example, a voltage signal of 2 V. The second electrical signal may be a signal greater than the preset voltage value, for example, a voltage signal greater than 2 V.

[0054] In some embodiments, the driving module 31 may include a logic controller, a voltage comparator, or other elements or circuits with control functions.

[0055] In other embodiments, the driving module 31 may include a voltage regulator, or other components or circuits having the same function as a voltage regulator. Figure 3 , shows a schematic structural diagram of an auxiliary power supply system 100 according to an embodiment of the present application. Figure 3 As shown, the power switching circuit 3 may include: a driving module 31, a switch module 32, and an output module 33. The driving module 31 includes a three-terminal voltage regulator 311, wherein the reference terminal of the three-terminal voltage regulator 311 is connected to the output terminal of the first power supply 1, the cathode terminal of the three-terminal voltage regulator 311 is connected to an input terminal of the switch module 32, and the anode terminal of the three-terminal voltage regulator 311 is grounded.

[0056] Based on this design, when the first power source 1 is energized, the cathode terminal of the three-terminal regulator 311 generates a first electrical signal. Thus, upon receiving the first electrical signal output by the three-terminal regulator 311, the switch module 32 can disconnect the second power source 2 from the output module 33, thereby stopping the second power source 2 from supplying power to the load 200.

[0057] When the first power source 1 is not powered, the cathode terminal of the three-terminal regulator 311 generates a second electrical signal. Therefore, upon receiving the second electrical signal output by the three-terminal regulator 311, the switch module 32 can conduct electricity between the second power source 2 and the output module 33, so that the second power source 2 supplies power to the load 200.

[0058] The three-terminal voltage regulator 311 can be a corresponding voltage regulator chip, such as a TL431 chip, depending on the actual situation. When the TL431 chip is in operation, it turns on and outputs a voltage signal, such as 2V, when the voltage at the reference terminal is greater than 2.5V. When the voltage at the reference terminal is less than 2.5V, it turns off and outputs another voltage signal, such as 0V.

[0059] For a better understanding, the following three-terminal voltage regulator 311 is TL431 chip as an example, and combined with Figure 4 The auxiliary power system 100 is further described.

[0060] Figure 4 This is a circuit diagram of the auxiliary power system 100 according to an embodiment of the present application. Figure 4 The reference terminal of the voltage regulator chip is connected to the first power supply 1, the output terminal of the voltage regulator chip is connected to the switch module 32, and the input terminal of the voltage regulator chip is grounded. When the voltage at the reference terminal of the voltage regulator chip is greater than 2.5V, the voltage regulator chip is turned on. Conversely, when the voltage at the reference terminal of the voltage regulator chip is less than 2.5V, the voltage regulator chip is turned off. When the voltage regulator chip is turned on, the output terminal can output a first electrical signal. Specifically, the first electrical signal can be a voltage signal of 2V (volts). When the TL431 is turned off, the output terminal can output a second electrical signal. Specifically, the second electrical signal can be a voltage signal greater than 2V (volts).

[0061] The driving module 31 may also include a voltage divider unit. The voltage divider unit is connected between the reference end of the three-terminal voltage regulator 311 and the output end of the first power supply 1. Specifically, the voltage divider unit includes a resistor R1 and a resistor R2, the resistor R1 is connected between the reference end of the voltage regulator chip and the output end of the first power supply 1, and the resistor R2 is connected to the reference end of the voltage regulator chip and grounded. In this case, when the first power supply 1 is energized, the voltage from the first power supply 1 to the reference end of the voltage regulator chip can be divided by the resistors R1 and R2 so that the reference end voltage of the voltage regulator chip is greater than 2.5V; when the first power supply 1 is not energized, there is no voltage on the resistors R1 and R2, and the reference end voltage of the voltage regulator chip is 0, that is, less than 2.5V.

[0062] The switch module 32 includes a first switch transistor Q1 and a second switch transistor Q2. The first end of the first switch transistor Q1 is connected to the output end of the driver module 31, the second end of the first switch transistor Q1 is connected to the zero potential point, the third end of the first switch transistor Q1 is connected to the first end of the second switch transistor Q2, the second end of the second switch transistor Q2 is connected to the output end of the second power supply 2, and the third end of the second switch transistor Q2 is connected to an input end of the output module 33.

[0063] It can be understood that the first switch tube Q1 is turned on and outputs the first electrical level to the second switch tube Q2 when receiving the first electrical signal, and the second switch tube Q2 is turned on when receiving the first electrical level. Specifically, when the first terminal of the first switch tube Q1 receives the first electrical signal, the second terminal of the first switch tube Q1 is connected to the third terminal of the first switch tube Q1, and the first electrical level is output from the third terminal of the first switch tube Q1 to the first terminal of the second switch tube Q2. When the first terminal of the second switch tube Q2 receives the first electrical level, the second terminal of the second switch tube Q2 is connected to the third terminal of the second switch tube Q2.

[0064] Similarly, when receiving the second electrical signal, the first switch transistor Q1 is turned off and outputs the second electrical level to the second switch transistor Q2. The second switch transistor Q2 is turned off when receiving the second electrical level. Specifically, when the first terminal of the first switch transistor Q1 receives the second electrical signal, the second terminal of the first switch transistor Q1 and the third terminal of the first switch transistor Q1 are disconnected, and the second electrical level is output from the third terminal of the first switch transistor Q1 to the first terminal of the second switch transistor Q2. When the first terminal of the second switch transistor Q2 receives the second electrical level, the second terminal of the second switch transistor Q2 and the third terminal of the second switch transistor Q2 are disconnected.

[0065] The first level may be a high level or a high impedance state relative to the second level, and the second level may be a low level state relative to the first level. For example, the first level may be represented by "1" and the second level may be represented by "0".

[0066] In some embodiments, the first switch transistor Q1 may be an NMOS switch transistor. The second switch transistor Q2 may be a PMOS switch transistor. The gate of the first switch transistor Q1 is connected to the output terminal of the driver module 31. Specifically, the gate of the first switch transistor Q1 is connected to the output terminal of the voltage regulator chip. The source of the first switch transistor Q1 is connected to the zero potential point. The drain of the first switch transistor Q1 is connected to the gate of the second switch transistor Q2. The source of the second switch transistor Q2 is connected to the output terminal of the second power supply 2, and the drain of the second switch transistor Q2 is connected to an input terminal of the output module 33.

[0067] In some embodiments, see Figure 4 , the switch module 32 may further include a current limiting unit. The second end of the second switch tube Q2 is connected to the output end of the driver module 31 through the current limiting unit, and the output end of the second power supply 2 is connected between the current limiting unit and the second end of the second switch tube Q2. Specifically, the current limiting unit includes a resistor R3, one end of which is connected to the output end of the voltage regulator chip, and the other end is connected between the output end of the second power supply 2 and the source of the second switch tube Q2. Therefore, when the driver module 31 outputs the first electrical signal, the current input to the first switch tube Q1 can be limited by the current limiting unit, and the current can be distributed to the second switch tube Q2. Therefore, the current limiting unit also acts as a driving voltage divider resistor for the second switch tube Q2.

[0068] In some embodiments, see Figure 4 The switch module 32 may further include a driving voltage divider unit. The driving voltage divider unit is connected between the output terminal of the driving module 31 and the first terminal of the first switch tube Q1. Specifically, the driving voltage divider unit includes resistors R4 and R5. One end of resistor R4 is connected to the output terminal of the voltage regulator chip and the other end is connected to the gate of the first switch tube Q1. One end of resistor R5 is connected to the gate of the first switch tube Q1 and the other end is grounded. Therefore, when the driving module 31 outputs the first electrical signal, the resistors R4 and R5 can divide the voltage of the first switch tube Q1 so that the first switch tube Q1 can operate normally.

[0069] The second input terminal of the output module 33 is connected to the output terminal of the first power supply 1 and is used to obtain power from the first power supply 1 when the first power supply 1 is powered. In this case, when one of the first power supply 1 and the second power supply 2 is powered, the power switching circuit 3 can select the powered auxiliary power source to power the load 200. If the first power supply 1 is powered and the second power supply 2 is not powered, the load 200 can obtain power directly from the first power supply 1 through the output module 33.

[0070] In some embodiments, see Figure 4The output module 33 may further include a first protection element D1 and a second protection element D2. The first input end of the output module 33 is connected to the output end of the switch module 32 through the first protection element D1, and the second input end of the output module 33 is connected to the output end of the first power supply 1 through the second protection element D2.

[0071] The first protection element D1 and the second protection element D2 may be diodes, for example.

[0072] In some embodiments, the output module 33 may further include an output interface 331. The output end of the output interface 331 is used to connect to the load 200, and the input end is used to connect to the first protection element D1 and the second protection element D2. Thus, the first power supply 1 or the second power supply 2 can power the load 200 through the output interface 331, while the first protection element D1 and the second protection element D2 can isolate the load 200, filter the current, and prevent current backflow.

[0073] Based on the above Figure 4 The circuit structure shown is Figure 4 The circuit shown operates as follows:

[0074] If the first power supply 1 is energized, the reference terminal voltage of the voltage regulator chip can be calculated according to the following formula:

[0075]

[0076] Among them, V ac_com is the output voltage of the first power supply 1, and Vref is the reference voltage of the voltage regulator chip. If the first power supply 1 is energized, and resistors R1 and R2 are selected with appropriate resistance values ​​according to formula (1) so that the reference voltage of the voltage regulator chip is greater than 2.5V, the voltage regulator chip is turned on and the voltage at the output of the voltage regulator chip, Vout, is approximately 2V, meaning that the first electrical signal is approximately 2V.

[0077] If the first power supply 1 is not charged and the second power supply 2 is charged, that is, V ac_com is 0, according to formula (1), Vref is also 0, then the voltage regulator chip is cut off and the voltage regulator chip outputs the second electrical signal.

[0078] If the first power source 1 is energized, the second electrical signal can be calculated according to the following formula:

[0079]

[0080] Among them, V dc_comis the output voltage of the second power supply 2. If the first power supply 1 is not powered and the second power supply 2 is powered, the second electrical signal is related to the resistors R3, R4, R5, and the output voltage of the second power supply 2. At this time, the gate voltage of the first switch Q1 can be calculated using the following formula:

[0081]

[0082] Wherein, Vg1 is the gate voltage of the first switch tube Q1. If the first power supply 1 is not powered and the second power supply 2 is powered, in order for the second power supply 2 to supply power to the load 200, the second switch tube Q2 needs to be turned on, that is, the gate voltage of the second switch tube Q2 needs to be set to a low level. Since the drain of the first switch tube Q1 is connected to the gate of the second switch tube Q2, the drain voltage of the first switch tube Q1 is equal to the gate voltage of the second switch tube Q2. Therefore, in order to make the drain of the first switch tube Q1 output a low level, the gate voltage of the first switch tube Q1 should be raised to turn on the first switch tube Q1. According to formula (2) and formula (3), the voltage Vout at the output end of the voltage regulator chip can be raised by selecting resistors R3, R4, and R5 with appropriate resistance values, thereby raising the gate voltage of the first switch tube Q1. After the voltage at the output end of the voltage regulator chip is raised, it becomes the second electrical signal. At this time, the voltage at the output end of the voltage regulator chip is much greater than 2V.

[0083] If the first power supply 1 is energized, the second switch Q2 must be turned off to stop the second power supply 2 from supplying power to the load 200. Specifically, the gate voltage of the second switch Q2 must be set to a high level or high impedance. Since the drain of the first switch Q1 is connected to the gate of the second switch Q2, the drain voltage of the first switch Q1 is equal to the gate voltage of the second switch Q2. Therefore, to turn off the drain of the first switch Q1 by reducing its gate voltage, the voltage at the output of the first switch Q1 must be approximately 2V.

[0084] Thus, even if both the first power supply 1 and the second power supply 2 are powered, and other loads 200 of the first power supply 1 and the second power supply 2 change, causing the output voltages of the first power supply 1 and the second power supply 2 to also change, the driver module 31 and the switch module 32 can force the first power supply 1 to power the load 200, thereby reducing the situation where power sources compete for load power and maintaining a stable supply voltage. This can improve the reliability of the auxiliary power supply system 100.

[0085] In addition, the driver module 31 can also output a second electrical signal to the switch module 32 when the first power supply 1 is not powered and the second power supply 2 is powered. Upon receiving the second electrical signal, the switch module 32 can connect the second power supply 2 to the output module 33 so that the second power supply 2 supplies power to the load 200. At the same time, the second input end of the output module 33 is connected to the output end of the first power supply 1. Thus, when one of the first power supply 1 and the second power supply 2 is powered, a powered auxiliary power source can be selected to supply power to the load 200. If the first power supply 1 is powered and the second power supply 2 is not powered, the load 200 can obtain power directly from the first power supply 1 through the output module 33. If the first power supply 1 is not powered and the second power supply 2 is powered, the load 200 can obtain power from the second power supply 2 through the switch module 32 and the output module 33.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A power switching circuit, characterized in that: include: Drive module, switch module and output module; The input end of the driving module is connected to the output end of the first power supply, and the output end of the driving module is connected to an input end of the switch module; The other input end of the switch module is connected to the output end of the second power supply, and the output end of the switch module is connected to the first input end of the output module; The second input terminal of the output module is connected to the output terminal of the first power supply and is used to obtain electric energy from the first power supply when the first power supply is powered, and the output terminal of the output module is connected to a load; The driving module is configured to output a first electrical signal to the switch module when the first power supply is powered, and to output a second electrical signal to the switch module when the first power supply is not powered and the second power supply is powered; The switch module is used to disconnect the second power supply and the output module when receiving the first electrical signal, so that the second power supply stops supplying power to the load; and the switch module is used to connect the second power supply and the output module when receiving the second electrical signal, so that the second power supply supplies power to the load.

2. The power switching circuit according to claim 1, wherein: The driving module includes a three-terminal voltage regulator, wherein the reference terminal of the three-terminal voltage regulator is connected to the output terminal of the first power supply, the cathode terminal of the three-terminal voltage regulator is connected to an input terminal of the switch module, and the anode terminal of the three-terminal voltage regulator is grounded; When the first power supply is powered, the cathode terminal of the three-terminal regulator generates the first electrical signal; When the first power source is not powered, the cathode terminal of the three-terminal regulator generates the second electrical signal.

3. The power switching circuit according to claim 2, wherein: The driving module further includes a voltage dividing unit connected between a reference terminal of the three-terminal voltage regulator and an output terminal of the first power supply.

4. The power switching circuit according to claim 1, wherein: The switch module includes a first switch tube and a second switch tube, wherein the first end of the first switch tube is connected to the output end of the driving module, the second end of the first switch tube is connected to the zero potential point, the third end of the first switch tube is connected to the first end of the second switch tube, the second end of the second switch tube is connected to the output end of the second power supply, and the third end of the second switch tube is connected to the input end of the output module; The first switch tube is turned on when receiving the first electrical signal and outputs the first electrical level to the second switch tube, and the second switch tube is turned on when receiving the first electrical level; The first switch tube is turned off when receiving the second electrical signal and outputs the second electrical level to the second switch tube, and the second switch tube is turned off when receiving the second electrical level.

5. The power switching circuit according to claim 4, wherein: The switch module includes a current limiting unit, the second end of the second switch tube is connected to the output end of the driving module through the current limiting unit, and the output end of the second power supply is connected between the current limiting unit and the second end of the second switch tube.

6. The power switching circuit according to claim 4, wherein: The switch module includes a driving voltage dividing unit connected between the output end of the driving module and the first end of the first switch tube.

7. The power switching circuit according to claim 1, wherein: The output module includes a first protection element and a second protection element. The first input end of the output module is connected to the output end of the switch module through the first protection element. The second input end of the output module is connected to the output end of the first power supply through the second protection element.

8. The power switching circuit according to claim 7, wherein: The first protection element and the second protection element are diodes.

9. An auxiliary power supply system, characterized in that: include: a first power supply, a second power supply, and a power switching circuit; The power switching circuit includes: a driving module, a switch module and an output module; The input end of the driving module is connected to the output end of the first power supply, and the output end of the driving module is connected to an input end of the switch module; The other input end of the switch module is connected to the output end of the second power supply, and the output end of the switch module is connected to the first input end of the output module; The second input terminal of the output module is connected to the output terminal of the first power supply and obtains electric energy from the first power supply when the first power supply is energized, and the output terminal of the output module is connected to a load; The driving module is configured to output a first electrical signal to the switch module when the first power supply is powered, and to output a second electrical signal to the switch module when the first power supply is not powered and the second power supply is powered; The switch module is used to disconnect the second power supply and the output module when receiving the first electrical signal, so that the second power supply stops supplying power to the load; and the switch module is used to connect the second power supply and the output module when receiving the second electrical signal, so that the second power supply supplies power to the load.

10. The auxiliary power supply system according to claim 9, characterized in that: The first power supply is an AC-to-DC power supply, the second power supply is a DC-to-DC power supply, and the load is an inverter.

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