TWI705650B - Dc-to-dc converter with bridgeless power factor correction function - Google Patents

Abstract

A DC-to-DC converter with a bridgeless power factor correction function is provided for providing uninterruptible power supply to a load. The DC-to-DC converter with the bridgeless power factor correction function includes a first circuit coupled to a live end of an AC power source, and a second circuit coupled to a neutral end of the AC power source. The first circuit includes a first energy storage unit coupled to the live end, and a voltage conversion circuit coupled to the neutral end. The second circuit includes a second energy storage unit coupled to the live end, and a power switching circuit coupled to the voltage conversion circuit and the neutral line end.

Description

DC-DC converter with bridgeless power factor correction function

The invention relates to a DC-to-DC converter, in particular to a DC-to-DC converter with a bridgeless power factor correction function applied in an uninterruptible power system.

Generally speaking, converters with bridgeless power factor correction (PFC) function are compared with traditional bridge rectifiers. Converters with bridgeless power factor correction function reduce the conduction of power diodes. Loss in turn improves efficiency. For example, when it is applied to the battery mode under the 3KVA architecture of the current Uninterruptible Power System (UPS), it can continuously provide backup AC power supply for load equipment such as electrical appliances in the case of abnormal grid or power outages. Equipment to maintain the normal operation of electrical appliances. Under normal circumstances, the uninterrupted power system is used to maintain uninterrupted power supply for key commercial equipment or precision instruments such as computers and servers to prevent data loss, communication interruption, or loss of control of the device.

However, the most common application of uninterruptible power systems (UPS) when operating in the battery mode under the 3KVA architecture is to work with lead-acid batteries. Lead-acid batteries are large in size, short in life, and time-consuming and costly in maintenance. And the traditional DC-to-DC (DC-to-DC) converter is a Push-Pull architecture, which is different from the Boost circuit at one end of the AC power grid. As a result, it will occupy too much wiring area on the circuit board, increase the circuit board substrate and process time, and due to lead-acid batteries The size and increase of the Push-Pull circuit architecture will increase the volume and cost of the uninterruptible power system.

For this reason, how to design an improved DC-to-DC converter, especially the improvement in the simplified circuit structure, to solve the aforementioned technical problems of the increase in the volume and cost of the uninterruptible power system, is an important research for the inventor of this case. Subject.

The purpose of the present invention is to provide a DC-to-DC converter with bridgeless power factor correction function, which can solve the aforementioned technical problems of increasing the volume and cost of the uninterruptible power system through the improvement of the simplified circuit structure, and reduce production The purpose of cost, increase production efficiency and use portability.

In order to achieve the foregoing objectives, the DC-DC converter with bridgeless power factor correction function proposed in the present invention is applied to provide uninterrupted power supply in the mains mode or battery mode to the load, and has the bridgeless power factor correction function. The DC-DC converter includes: a first circuit coupled to the live terminal of the AC power source; the first circuit includes a first energy storage unit and a voltage conversion circuit coupled in series; wherein the first energy storage unit is coupled to the live terminal, and the voltage The conversion circuit is coupled to the neutral terminal of the AC power supply; and the second circuit is coupled to the neutral terminal of the AC power supply and is coupled to the first circuit; the second circuit includes a second energy storage unit and a power switch coupled in series Circuit; wherein the second energy storage unit is coupled to the live terminal, and the power switch circuit is coupled to the voltage conversion circuit and the neutral terminal; wherein, when the AC power supply is normal, the AC power supply provides power supply in the commercial mode to the load through the first circuit; When the AC power source is abnormal, the second energy storage unit provides battery-mode power supply to the load through the power switch circuit and the first circuit.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, the voltage conversion circuit includes a first transistor switch and a second transistor switch coupled in series, and the first and second transistor switches coupled in series. A pole body and a first capacitor, a second diode and a second capacitor coupled in series; wherein, the first transistor switch is coupled to the first energy storage unit, the first diode and the second diode; the second The transistor switch is coupled to the second circuit, the first capacitor and the second capacitor.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, the power switch circuit includes a third diode and a third transistor switch and a fourth transistor switch coupled in series; wherein , The third transistor switch is coupled to the second transistor switch, the first capacitor, the second capacitor, and the neutral terminal, the fourth transistor switch is coupled to the second energy storage unit; one end of the third diode is coupled to the first A diode and the first capacitor, and the other end of the third diode is coupled to the third transistor switch and the fourth transistor switch.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, when operating in the mains mode and when the DC-DC converter is in positive half-cycle operation: the first transistor switch is turned on, The second transistor switch is turned on, the third transistor switch is turned off, and the fourth transistor switch is turned off, the first energy storage unit is an energy storage operation; and the first transistor switch is turned off, the second transistor switch is turned off, The third transistor switch is turned off and the fourth transistor switch is turned off, and the first energy storage unit is in an energy release operation.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, when operating in the mains mode and when the DC-DC converter is in negative half cycle operation: the first transistor switch is turned on, The second transistor switch is turned on, the third transistor switch is turned off, and the fourth transistor switch is turned off, the first energy storage unit is an energy storage operation; and the first transistor switch is turned off, the second transistor switch is turned off, The third transistor switch is turned off and the fourth transistor switch is turned off, and the first energy storage unit is in an energy release operation.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, when operating in battery mode and when the DC-DC converter is in positive half-cycle operation: the first transistor switch is turned on, The second transistor switch is turned on, the third transistor switch is turned on, and the fourth transistor switch is turned on. The first energy storage unit is for energy storage operation; and the first transistor switch is turned on, the second transistor switch is turned on, and the third transistor is turned on. The switch is turned off and the fourth transistor switch is turned on, and the first energy storage unit is in a discharge operation.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, when operating in battery mode and when the DC-DC converter is in negative half cycle operation: the first transistor switch is turned on, The second transistor switch is turned on, the third transistor switch is turned on, and the fourth transistor switch is turned on. The first energy storage unit is an energy storage operation; and the first transistor switch is turned off, the second transistor switch is turned off, and the third transistor is turned off. The transistor switch is turned on and the fourth transistor switch is turned on, and the first energy storage unit is operated for discharging energy.

Furthermore, in the DC-DC converter with bridgeless power factor correction function, the first energy storage unit is an inductor and the second energy storage unit is a lithium battery.

When using the DC-to-DC converter with the bridgeless power factor correction function of the present invention, if the AC power supply is normal, the AC power supply provides power supply in the commercial mode to the load through the first circuit, wherein the voltage conversion of the first circuit The circuit can perform voltage conversion processing on the AC power supply (for example: Boost) and then provide it to the load; if the AC power supply is abnormal (for example: surge, undervoltage or power failure), the power switch circuit in the second circuit can be turned on through the circuit With the control of shut-off, the electric energy output by the second energy storage unit can enter the voltage conversion circuit of the first circuit through the power switch circuit for voltage conversion processing, so that the second energy storage unit provides the load to the load through the power switch circuit and the first circuit. Power supply in battery mode.

Therefore, when the AC power supply is abnormal, the second energy storage unit can perform voltage conversion processing through the voltage conversion circuit of the first circuit only through the power switch circuit, without the need for additional independent of the AC power flow path. For other voltage conversion circuits (such as Push-Pull converters), the present invention simplifies the improvement of the circuit structure, does not need to occupy additional circuit board volume and wiring area, can reduce the circuit board base material and process time, and solve the problem of uninterrupted power supply. The volume and cost of the system increase the technical problems, and achieve the purpose of reducing production costs, improving production efficiency and portable use.

In order to further understand the technology, means and effects of the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. I believe that the features and characteristics of the present invention can be obtained from this in-depth and specific understanding. However, the accompanying drawings are only provided for reference and illustration, and are not intended to limit the present invention.

10: The first circuit

11: The first energy storage unit

12: Voltage conversion circuit

20: second circuit

21: The second energy storage unit

22: Power switch circuit

L1: The first energy storage unit

B1: The second energy storage unit

200: load

300: Input filter circuit

400: inverter

500: output filter circuit

Q1: The first transistor switch

Q2: The second transistor switch

Q3: The third transistor switch

Q4: The fourth transistor switch

C1: The first capacitor

C2: second capacitor

L: live end

N: Neutral terminal

Lns1: first energy storage path

Lns2: second energy storage path

Lns3: third energy storage path

Lns4: fourth energy storage path

Lnr1: The first energy release path

Lnr2: second energy release path

Lnr3: The third energy release path

Lnr4: The fourth path of discharging energy

D1: The first diode

D2: The second diode

D3: The third diode

Fig. 1 is a schematic diagram of an embodiment of the DC-DC converter with bridgeless power factor correction function configured in an uninterruptible power system; Fig. 2 is a schematic diagram of the bridgeless power factor correction according to the present invention A schematic circuit diagram of this embodiment of a functional DC-DC converter; FIG. 3 is the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operating in the mains mode and positive half-cycle operation Figure 4 is a schematic diagram of the first energy release path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention is operating in the mains mode and operating in a positive half cycle ； 5 is a schematic diagram of the second energy storage path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in the mains mode and operates in a negative half cycle; FIG. 6 is the present invention The schematic diagram of the second energy release path of this embodiment of the DC-DC converter with bridgeless power factor correction function operating in the mains mode and negative half cycle operation; FIG. 7 is the bridgeless power factor correction according to the present invention The schematic diagram of the third energy storage path when this embodiment of the functional DC-DC converter operates in battery mode and is in positive half-cycle operation; FIG. 8 is the DC-DC converter with bridgeless power factor correction function according to the present invention This embodiment is a schematic diagram of the third energy release path when the embodiment is operating in battery mode and is operating in a positive half cycle; FIG. 9 is the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operating on the battery A schematic diagram of the fourth energy storage path when operating in a negative half cycle mode; and FIG. 10 is the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operating in battery mode and operating in negative half cycle Schematic diagram of the fourth energy release path at time.

The following is a specific embodiment to illustrate the implementation of the present invention. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied by other different specific examples, and various details in the specification of the present invention can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention.

It should be noted that the structure, ratio, size, number of components, etc. shown in the accompanying drawings in this specification are only used to match the content disclosed in the specification for the understanding and reading of those familiar with this technology, and are not intended to limit the scope of the present invention. The limited conditions for implementation do not have any technical significance. Any structural modification, proportional relationship change, or size adjustment should fall within the scope of the present invention without affecting the effects and objectives that can be achieved. The technical content disclosed by the invention can be covered.

The technical content and detailed description of the present invention are described below with the drawings.

Please refer to FIG. 1 and FIG. 2. In which, FIG. 1 is a schematic diagram of an embodiment of the DC-DC converter with bridgeless power factor correction function according to the present invention configured in an uninterrupted power system; FIG. 2 It is a circuit diagram of this embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention. An embodiment of the DC-to-DC converter with bridgeless power factor correction function of the present invention is applied to provide uninterrupted power supply in mains mode or battery mode to the load 200, and the DC coupler with bridgeless power factor correction function The DC converter includes: a first circuit 10 and a second circuit 20.

Among them, the first circuit 10 is coupled to the live terminal L of the AC power supply; the first circuit 10 includes a first energy storage unit 11 coupled in series (the element labeled L1 in the figure, in this embodiment, an inductor) and a voltage conversion Circuit 12; Among them, the first energy storage unit 11 is coupled to the live terminal L, and the voltage conversion circuit 12 is coupled to the neutral terminal N of the AC power supply. In detail, the voltage conversion circuit 12 includes a first transistor switch Q1 and a second transistor switch Q2 coupled in series, a first diode D1 and a first capacitor C1 coupled in series, a second diode coupled in series Body D2 and the second capacitor C2; wherein, the first transistor switch Q1 is coupled to the first energy storage unit L1, the first diode D1 and the second Diode D2; The second transistor switch Q2 is coupled to the second circuit 20, the first capacitor C1 and the second capacitor C2.

The second circuit 20 is coupled to the neutral terminal N of the AC power supply and is coupled to the first circuit 10; the second circuit 20 includes a second energy storage unit 21 coupled in series (the element labeled B1 in the figure, in this embodiment The middle is a lithium battery) and the power switch circuit 22; wherein the second energy storage unit 21 is coupled to the live terminal L, and the power switch circuit 22 is coupled to the voltage conversion circuit 12 and the neutral terminal N. In detail, the power switch circuit 22 includes a third diode D3 and a third transistor switch Q3 and a fourth transistor switch Q4 coupled in series; wherein the third transistor switch Q3 is coupled to the second transistor switch Q2 , The first capacitor C1, the second capacitor C2 and the neutral terminal N, the fourth transistor switch Q4 is coupled to the second energy storage unit B1; one end of the third diode D3 is coupled to the first diode D1 and the second A capacitor C1, the other end of the third diode D3 is coupled to the third transistor switch Q3 and the fourth transistor switch Q4. Incidentally, the aforementioned transistor switches can be, for example, but not limited to, metal oxide semiconductor field effect transistors (MOSFET), bipolar junction transistors (BJT) or insulated gate bipolar transistors (IGBT) .

In the embodiment of the present invention, the DC-DC converter with bridgeless power factor correction function is coupled to the input filter circuit 300, which can be an EMI filter circuit to filter out the input AC power Noise such as Electromagnetic Interference (EMI) (as shown in Figure 1), and the DC-DC converter with bridgeless power factor correction function is coupled to the inverter 400 to the bridgeless The DC power factor correction function of the DC-DC converter converts the DC power supply output to the AC power supply, and is coupled to the output filter circuit 500, which can be an EMI filter circuit to filter out electromagnetic interference output to the load 200 Wait for noise. Among them, when the AC power is normal, the AC power is provided to the load 200 through the first circuit 10 Power supply in the mains mode; when the AC power supply is abnormal, the second energy storage unit 21 provides battery mode power supply to the load 200 through the power switch circuit 22 and the first circuit 10. Therefore, when the AC power supply is normal or abnormally fails, it is possible to achieve uninterrupted power supply to the load 200.

Please refer to FIG. 3 and FIG. 4. FIG. 3 is the first energy storage when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in the mains mode and operates in a positive half cycle. Path schematic diagram; FIG. 4 is a schematic diagram of the first energy-releasing path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in the mains mode and is operating in a positive half cycle. The DC-DC converter with bridgeless power factor correction function operates in the mains mode (when the AC power supply is normal), and when the DC-DC converter operates in a positive half cycle: as shown in Figure 3, through Control the first transistor switch Q1 to turn on, the second transistor switch Q2 to turn on, the third transistor switch Q3 to turn off, and the fourth transistor switch Q4 to turn off. At this time, the first energy storage unit L1 is an energy storage operation. -storing operation); when the first energy storage unit L1 is in energy storage operation, the live terminal L, the first energy storage unit L1, the first transistor switch Q1, the second transistor switch Q2 and the neutral terminal N form a pair The first energy storage path Lns1 for the energy storage of the first energy storage unit L1; and as shown in FIG. 4, by controlling the first transistor switch Q1 to turn off, the second transistor switch Q2 to turn off, and the third transistor switch Q3 to turn off And the fourth transistor switch Q4 is off. At this time, the first energy storage unit L1 is in an energy-releasing operation; when the first energy storage unit L1 is in an energy-releasing operation, the live terminal L and the first The energy storage unit L1, the first diode D1, the first capacitor C1, and the neutral terminal N form a first energy release path Lnr1 for the first energy storage unit L1 to release energy.

Please refer to FIG. 5 and FIG. 6. FIG. 5 is the second energy storage when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in the mains mode and operates in the negative half cycle Path schematic diagram; FIG. 6 is a schematic diagram of the second energy release path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention is operated in the mains mode and negative half-cycle operation. The DC-DC converter with bridgeless power factor correction function operates in the mains mode (when the AC power supply is normal), and when the DC-DC converter operates in a negative half cycle: as shown in Figure 5, through Control the first transistor switch Q1 to turn on, the second transistor switch Q2 to turn on, the third transistor switch Q3 to turn off, and the fourth transistor switch Q4 to turn off. At this time, the first energy storage unit L1 is in energy storage operation; When the first energy storage unit L1 is in the energy storage operation, the neutral terminal N, the second transistor switch Q2, the first transistor switch Q1, the first energy storage unit L1, and the live terminal L form a pair of the first energy storage unit L1 The second energy storage path Lns2 for energy storage.

As shown in Figure 6, by controlling the first transistor switch Q1 to turn off, the second transistor switch Q2 to turn off, the third transistor switch Q3 to turn off, and the fourth transistor switch Q4 to turn off, at this time, the first storage The energy unit L1 is a discharging operation; when the first energy storage unit L1 is a discharging operation, the neutral terminal N, the second capacitor C2, the second diode D2, the first energy storage unit L1 and the live terminal L are formed The second energy release path Lnr2 for the first energy storage unit L1 to release energy.

Please refer to FIG. 7 and FIG. 8. FIG. 7 is the third energy storage when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in battery mode and operates in a positive half cycle. Path schematic diagram; FIG. 8 is a schematic diagram of the third energy-releasing path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in battery mode and operates in a positive half cycle. The said DC-DC converter with bridgeless power factor correction function is Operating in battery mode (when the AC power supply is abnormal), and when the DC-DC converter is in positive half-cycle operation: as shown in Figure 7, by controlling the first transistor switch Q1 to turn on, the second transistor switch Q2 to turn on, and the The three-transistor switch Q3 is turned on and the fourth transistor switch Q4 is turned on. At this time, the first energy storage unit L1 is in energy storage operation; when the first energy storage unit L1 is in energy storage operation, the anode of the second energy storage unit B1 , The fourth transistor switch Q4, the third transistor switch Q3, the second transistor switch Q2, the first transistor switch Q1, the first energy storage unit L1, and the negative electrode of the second energy storage unit B1 form a pair of first energy storage The third energy storage path Lns3 for the energy storage of the unit L1.

As shown in Figure 8, by controlling the first transistor switch Q1 to turn on, the second transistor switch Q2 to turn on, the third transistor switch Q3 to turn off, and the fourth transistor switch Q4 to turn on, at this time, the first energy storage unit L1 It is a discharging operation; when the first energy storage unit L1 is discharging operation, the anode of the second energy storage unit B1, the fourth transistor switch Q4, the third transistor switch Q3, the first capacitor C1, and the second transistor switch Q2, the first transistor switch Q1, the first energy storage unit L1, and the negative electrode of the second energy storage unit B1 form a third energy release path Lnr3 for the first energy storage unit L1 to release energy.

Please refer to FIG. 9 and FIG. 10. FIG. 9 is the fourth energy storage when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention is operated in battery mode and negative half cycle operation Path schematic diagram; FIG. 10 is a schematic diagram of the fourth energy-releasing path when the embodiment of the DC-DC converter with bridgeless power factor correction function of the present invention operates in battery mode and negative half-cycle operation. When the DC-DC converter with bridgeless power factor correction function operates in battery mode (when the AC power supply is abnormal), and when the DC-DC converter operates in a negative half cycle: As shown in Figure 9, by controlling the first transistor switch Q1 to turn on, the second transistor switch Q2 to turn on, the third transistor switch Q3 to turn on, and the fourth transistor switch Q4 to turn on, at this time, the first energy storage unit L1 is Energy storage operation; when the first energy storage unit L1 is in energy storage operation, the anode of the second energy storage unit B1, the fourth transistor switch Q4, the third transistor switch Q3, the second transistor switch Q2, the first transistor The crystal switch Q1, the first energy storage unit L1, and the negative electrode of the second energy storage unit B1 form a fourth energy storage path Lns4 for storing energy in the first energy storage unit L1.

As shown in Figure 10, by controlling the first transistor switch Q1 to turn off, the second transistor switch Q2 to turn off, the third transistor switch Q3 to turn on, and the fourth transistor switch Q4 to turn on, at this time, the first energy storage unit L1 is the energy release operation; when the first energy storage unit L1 is the energy release operation, the anode of the second energy storage unit B1, the fourth transistor switch Q4, the third transistor switch Q3, the second capacitor C2, and the second two poles The body D2, the first energy storage unit L1, and the negative electrode of the second energy storage unit B1 form a fourth energy discharge path Lnr4 for the first energy storage unit L1 to discharge energy.

As mentioned above, when using the DC-to-DC converter with bridgeless power factor correction function of the present invention, if the AC power supply is normal, the AC power supply provides power supply in the commercial power mode to the load 200 through the first circuit 10, wherein , The voltage conversion circuit 12 of the first circuit 10 can perform voltage conversion processing (for example: Boost) on the AC power supply and then provide it to the load; if the AC power supply is abnormal (for example, surge, undervoltage or power failure), the second circuit 20 The power switch circuit 22 in the third transistor switch Q3 and the fourth transistor switch Q4 can be turned on and off, so that the electrical energy output by the second energy storage unit B1 can enter the first circuit 10 through the power switch circuit 22 The voltage conversion circuit 12 performs voltage conversion processing, so that the second energy storage unit B1 provides battery mode power supply to the load 200 through the power switch circuit 22 and the first circuit 10.

Therefore, when the AC power supply is abnormal, the second energy storage unit B1 can perform voltage conversion processing through the voltage conversion circuit 12 of the first circuit 10 only through the power switch circuit 22, without the need for additional independent AC power flow through For other voltage conversion circuits outside the path (for example: Push-Pull converter), the present invention simplifies the improvement of the circuit structure, does not need to occupy additional circuit board volume and wiring area, can reduce the circuit board base material and process time, and also It can reduce the use of circuit components, thereby solving the technical problems of increasing the volume and cost of the uninterruptible power system, so as to achieve the purpose of reducing production costs, reducing component costs, improving production efficiency and portable use.

In addition, the second energy storage unit 21 of the present invention does not use a traditional lead-acid battery, but a lithium battery. The conventionally known lead-acid battery has a large volume, a heavy weight, and a short service life. Disadvantages, for this reason, the DC-DC converter with bridgeless power factor correction function of the present invention has other advantages such as small size, light weight, better service life and reliability.

The above are only detailed descriptions and drawings of the preferred embodiments of the present invention. However, the features of the present invention are not limited to these, and are not intended to limit the present invention. The full scope of the present invention should be covered by the following patent application scope As the criterion, all embodiments that conform to the spirit of the patent application of the present invention and similar changes should be included in the scope of the present invention. Anyone familiar with the art in the field of the present invention can easily think of changes or Modifications can be covered in the following patent scope of this case.

10: The first circuit

11: The first energy storage unit

12: Voltage conversion circuit

20: second circuit

21: The second energy storage unit

22: Power switch circuit

200: load

300: Input filter circuit

400: inverter

500: output filter circuit

Claims (11)

A DC-to-DC converter with bridgeless power factor correction function, which is used to provide uninterrupted power supply in a mains mode or a battery mode to a load. The DC-to-DC converter with bridgeless power factor correction function It includes: a first circuit coupled to a live wire terminal of an AC power supply; the first circuit includes a first energy storage unit and a voltage conversion circuit coupled in series; wherein the first energy storage unit is coupled to the live wire Terminal, the voltage conversion circuit is coupled to a neutral terminal of the AC power source; and a second circuit is coupled to the neutral terminal of the AC power source and coupled to the first circuit; the second circuit includes a series connection Is coupled to a second energy storage unit and a power switch circuit; wherein, the second energy storage unit is coupled to the live terminal, and the power switch circuit is coupled to the voltage conversion circuit and the neutral terminal; wherein, when the When the AC power supply is normal, the AC power supply supplies the load in the commercial power mode through the first circuit; when the AC power supply is abnormal, the second energy storage unit supplies the load to the load through the power switch circuit and the first circuit The battery mode power supply; wherein, the voltage conversion circuit includes a first diode and a first capacitor coupled in series, and the power switch circuit includes a third diode and a third transistor coupled in series Switch and a fourth transistor switch, one end of the third diode is directly coupled to the first diode and the first capacitor, and the other end of the third diode is coupled to the third transistor switch And the fourth transistor switch. The DC-DC converter with bridgeless power factor correction function described in the first item of the scope of patent application, wherein the voltage conversion circuit includes a first transistor switch and a second transistor switch coupled in series, A second diode and a second capacitor coupled in series; Wherein, the first transistor switch is coupled to the first energy storage unit, the first diode and the second diode; the second transistor switch is coupled to the second circuit, the first capacitor and the The second capacitor. The DC-DC converter with bridgeless power factor correction function described in item 2 of the scope of patent application, wherein the third transistor switch is coupled to the second transistor switch, the first capacitor, and the second transistor The capacitor and the neutral terminal, and the fourth transistor switch is coupled to the second energy storage unit. For example, the DC-DC converter with bridgeless power factor correction function described in item 3 of the scope of patent application, wherein, when operating in the mains mode, and when the DC-DC converter is operating in a positive half cycle: The first transistor switch is turned on, the second transistor switch is turned on, the third transistor switch is turned off, and the fourth transistor switch is turned off, the first energy storage unit is an energy storage operation; and the first transistor The crystal switch is turned off, the second transistor switch is turned off, the third transistor switch is turned off, and the fourth transistor switch is turned off, and the first energy storage unit is in an energy release operation. The DC-DC converter with bridgeless power factor correction function as described in item 4 of the scope of patent application, wherein, when the first energy storage unit is in energy storage operation, the live terminal and the first energy storage unit , The first transistor switch, the second transistor switch, and the neutral terminal form a first energy storage path; and when the first energy storage unit is in an energy release operation, the live terminal, the first energy storage The energy unit, the first diode, the first capacitor and the neutral terminal form a first energy release path. For example, the DC-DC converter with bridgeless power factor correction function described in item 3 of the scope of patent application, wherein, when operating in the mains mode, and when the DC-DC converter is operating in a negative half cycle: The first transistor switch is turned on, the second transistor switch is turned on, the third transistor switch is turned off, and the fourth transistor switch is turned off, the first energy storage unit is an energy storage operation; and the first transistor The crystal switch is turned off, the second transistor switch is turned off, the third transistor switch is turned off, and the fourth transistor switch is turned off, and the first energy storage unit is in an energy release operation. The DC-DC converter with bridgeless power factor correction function described in item 6 of the scope of patent application, wherein, when the first energy storage unit is in energy storage operation, the neutral terminal and the second power The crystal switch, the first transistor switch, the first energy storage unit, and the live wire end form a second energy storage path; and when the first energy storage unit is in an energy release operation, the neutral wire end and the first The two capacitors, the second diode, the first energy storage unit and the live terminal form a second energy release path. The DC-DC converter with bridgeless power factor correction function described in item 3 of the scope of patent application, wherein, when operating in the battery mode, and when the DC-DC converter is operating in a positive half cycle: The first transistor switch is turned on, the second transistor switch is turned on, the third transistor switch is turned on, and the fourth transistor switch is turned on, the first energy storage unit is an energy storage operation; and the first transistor switch When turned on, the second transistor switch is turned on, the third transistor switch is turned off, and the fourth transistor switch is turned on, the first energy storage unit is in an energy release operation. The DC-DC converter with bridgeless power factor correction function described in item 8 of the scope of patent application, wherein, when the first energy storage unit is in energy storage operation, a positive electrode of the second energy storage unit, The fourth transistor switch, the third transistor switch, the second transistor switch, the first transistor switch, the first energy storage unit, and a negative electrode of the second energy storage unit form a third energy storage unit Path; and when the first energy storage unit is in a discharge operation, the anode of the second energy storage unit, the fourth transistor switch, the third transistor switch, the first capacitor, the second transistor The switch, the first transistor switch, the first energy storage unit and the negative electrode of the second energy storage unit form a third energy release path. The DC-DC converter with bridgeless power factor correction function described in item 3 of the scope of patent application, wherein, when operating in the battery mode and when the DC-DC converter is operating in a negative half cycle: The first transistor switch is turned on, the second transistor switch is turned on, the third transistor switch is turned on, and the fourth transistor switch is turned on, the first energy storage unit is an energy storage operation; and the first transistor switch Turning off, the second transistor switch is turned off, the third transistor switch is turned on, and the fourth transistor switch is turned on, and the first energy storage unit is in an energy release operation. The DC-DC converter with bridgeless power factor correction function described in item 10 of the scope of patent application, wherein, when the first energy storage unit is in energy storage operation, a positive electrode of the second energy storage unit, The fourth transistor switch, the third transistor switch, the second transistor switch, the first transistor switch Off, the first energy storage unit and a negative electrode of the second energy storage unit form a fourth energy storage path; and when the first energy storage unit is discharging operation, the positive electrode and the second energy storage unit The fourth transistor switch, the third transistor switch, the second capacitor, the second diode, the first energy storage unit and the negative electrode of the second energy storage unit form a fourth energy release path.

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