CN107070190B - Power supply device and capacitance heating control method thereof - Google Patents

Abstract

The embodiment of the invention provides a power supply device and a capacitance heating control method thereof, wherein the power supply device comprises a voltage conversion circuit and a heating control circuit; the voltage conversion circuit comprises a switching power supply circuit, a first capacitor and a second capacitor, wherein the first end of the first capacitor is electrically connected with the voltage input end of the switching power supply circuit, and the first end of the second capacitor is connected with the voltage output end of the switching power supply circuit; the heating control circuit comprises a controllable switch electrically connected between the voltage input end and the voltage output end, and is used for conducting under the driving of a preset switch control signal and forming a charge-discharge loop between the first capacitor and the second capacitor; the charge and discharge loop is used for conducting charge and discharge current and heating the second capacitor through the charge and discharge current. The embodiment of the invention can effectively prevent the influence on the normal use of the power supply device due to the reduction of the capacitance under the low-temperature condition.

Description

A power supply device and its capacitive heating control method

technical field

The invention relates to the technical field of power supplies, and in particular, to a power supply device and a method for controlling capacitive heating thereof.

Background technique

In all kinds of switching power supplies, the electrolytic capacitors used as output filter capacitors will have obvious capacity reduction at low temperature, and the capacity of some types of electrolytic capacitors will decrease by more than 50% at low temperature. The large reduction in the capacity of the output filter capacitor will lead to various failures of the switching power supply. For example, starting the power supply with a heavy load may cause the voltage of the output filter capacitor to be unstable, thus exceeding the voltage specification of the switching tube of the switching power supply. At present, in the application of switching power supply, in order to prevent the above problems caused by too low temperature, the usual practice is to give the switching power supply a certain heating time, which generally takes a few minutes to half an hour. Wait until the capacity of the electrolytic capacitor reaches the required value before connecting to the load. In addition, a heater is also provided at the bottom end of the electrolytic capacitor, and when the switching power supply is turned on, the heater is firstly controlled by the heating control circuit to heat the electrolytic capacitor, so that the capacity of the electrolytic capacitor returns to the normal value. However, if a heater is not provided, the heat engine of the switching power supply usually takes a long time, and the working efficiency of the switching power supply under low temperature conditions cannot be guaranteed; if a heater is provided, the production cost of the switching power supply will increase.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a power supply device and a method for controlling capacitance heating thereof, which can realize capacitive heating of the power supply device under low temperature conditions at a lower cost, thereby ensuring the working efficiency of the power supply device under low temperature conditions.

A first aspect of the embodiments of the present invention provides a power supply device, which is characterized by comprising: a voltage conversion circuit and a heating control circuit;

The voltage conversion circuit includes a switching power supply circuit, a first capacitor and a second capacitor, the switching power supply circuit includes a voltage input end and a voltage output end, and the first end of the first capacitor is electrically connected to the voltage input end, The first end of the second capacitor is connected to the voltage output end, and the second end of the first capacitor is electrically connected to the second end of the second capacitor;

The heating control circuit includes a controllable switch, the controllable switch is electrically connected between the voltage input terminal and the voltage output terminal, and the controllable switch is used to conduct under the driving of a preset switch control signal , and a charge-discharge loop is formed between the first capacitor and the second capacitor;

The charging and discharging circuit is used for conducting charging and discharging current between the first capacitor and the second capacitor, and heating the second capacitor through the charging and discharging current.

Wherein, the controllable switch in the heating control circuit is controlled to be turned on by the preset switch control signal, thereby forming a charging and discharging loop between the first capacitor and the second capacitor. Under the action of the capacitor, heat will be generated, and then the second capacitor can be heated by the charging and discharging current between the first capacitor and the second capacitor, which can effectively prevent the capacity of the second capacitor from being in low temperature conditions. Under low temperature conditions, there is a significant drop, which affects the normal use of the power supply device, so as to ensure the working efficiency of the power supply device under low temperature conditions.

In an embodiment, the heating control circuit further includes a current limiting resistor, which is connected in series with the controllable switch to limit the magnitude of the charging and discharging current on the charging and discharging loop.

Wherein, the current limiting resistor can prevent the controllable switch from being damaged due to excessive charging and discharging current on the charging and discharging circuit.

In an embodiment, the power supply device further includes a switch drive circuit, the switch drive circuit is electrically connected to the control terminal of the controllable switch, and is used for outputting the preset switch control signal, and according to the preset switch control signal It is assumed that a switch control signal drives the controllable switch to be turned on or off.

In one embodiment, the switch driving circuit is an isolated driving circuit.

In one embodiment, the switch driving circuit includes an optocoupler and a driver, one end of the optocoupler is electrically connected to the signal output end of the driver, and the other end of the optocoupler is electrically connected to the control end of the controllable switch, The preset switch control signal output by the signal output terminal of the driver is coupled to the control terminal of the controllable switch.

Wherein, the switch drive circuit is set as an isolated drive circuit through the optocoupler, so that the switch drive circuit can be effectively prevented from interfering with the switch power supply circuit of the power supply device, thereby ensuring the switching power supply circuit. stability.

In one embodiment, the switching power supply circuit includes an energy storage inductor, a first switch transistor and a second switch transistor, a first end of the energy storage inductor is electrically connected to the voltage input end, and the energy storage inductor The second end of the first switch tube is electrically connected to the first end of the first switch tube and the first end of the second switch tube, and the second end of the first switch tube is electrically connected to the second end of the first capacitor and the The second end of the second capacitor is electrically connected, and the second end of the second switch tube is electrically connected to the voltage output end.

In an embodiment, the preset switch control signal is the same as the drive signal of the first switch tube.

Wherein, by setting the preset switch control signal to be the same as the drive signal of the first switch tube, the first switch tube can be turned on and charge the energy storage inductor while controlling the The controllable switch is turned on to form the charging and discharging circuit, and then the second capacitor is heated, and there is no need to separately set a driving circuit for the controllable switch, so that the interference of the separately provided driving circuit to the switching power supply circuit can be prevented, And reduce the production cost of the power supply device.

In one embodiment, the power supply device further includes a capacitance detection circuit electrically connected to the switch driving circuit, and the capacitance detection circuit is further electrically connected to the first capacitor and the second capacitor, using When the capacity of the second capacitor is detected, and when the capacity of the second capacitor exceeds a preset threshold, the switch driving circuit is triggered to stop working, and the power supply device enters a normal working state.

In one embodiment, the capacitance detection circuit includes a voltage detection circuit and a capacitance calculation circuit, and the voltage detection circuit is electrically connected to the first capacitor and the second capacitor, and is used for switching between the controllable switch During the conduction period, the voltage of the first capacitor is detected, and the voltage of the second capacitor is detected at least twice, wherein the time interval between two adjacent detections of the voltage of the second capacitor is a preset time interval, and respectively The first voltage of the second capacitor and the second voltage of the second capacitor are obtained, and the capacity calculation circuit is used to calculate the first voltage of the second capacitor according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor. and the preset time interval, calculate the capacity of the second capacitor.

Wherein, in the process of heating the second capacitor, by detecting the capacity of the second capacitor, when the capacity of the second capacitor exceeds a preset threshold, the controllable switch can be triggered to turn off, that is, When the capacity of the second capacitor can meet the load driving requirement of the power supply device, the heating of the second capacitor is stopped, so that the capacity of the second capacitor can be restored to the required capacity while effectively The power consumption of the power supply device is controlled.

A second aspect of the embodiments of the present invention provides a capacitive heating control method, including:

A heating control circuit is provided between the voltage input end and the voltage output end of the voltage conversion circuit, and the heating control circuit includes a controllable switch;

Drive the controllable switch to conduct according to the preset switch control signal, and form a charge-discharge loop between the first capacitor and the second capacitor of the voltage conversion circuit;

A charging and discharging current is conducted between the first capacitor and the second capacitor through the charging and discharging circuit, and the second capacitor is heated by the charging and discharging current.

Wherein, the controllable switch in the heating control circuit is controlled to be turned on by the preset switch control signal, thereby forming a charging and discharging loop between the first capacitor and the second capacitor. Under the action of the capacitor, heat will be generated, and then the second capacitor can be heated by the charging and discharging current between the first capacitor and the second capacitor, which can effectively prevent the capacity of the second capacitor from being in low temperature conditions. Under low temperature conditions, there is a significant drop, which affects the normal use of the power supply device, so as to ensure the working efficiency of the power supply device under low temperature conditions.

In one embodiment, the method further includes: detecting the capacity of the second capacitor, and when the capacity of the second capacitor exceeds a preset threshold, triggering the switch driving circuit to stop working, and the power supply device into the normal working state.

In one embodiment, the detecting the capacity of the second capacitor includes:

detecting the voltage of the first capacitor during the conduction period of the controllable switch;

During the conduction period of the controllable switch, the voltage of the second capacitor is detected at least twice, and the first voltage of the second capacitor and the second voltage of the second capacitor are obtained respectively, wherein two adjacent detections are performed. The time interval of the voltage of the second capacitor is a preset time interval;

The capacity of the second capacitor is calculated according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor, and the preset time interval.

Wherein, in the process of heating the second capacitor, by detecting the capacity of the second capacitor, when the capacity of the second capacitor exceeds a preset threshold, the controllable switch can be triggered to turn off, that is, When the capacity of the second capacitor can meet the load driving requirement of the power supply device, the heating of the second capacitor is stopped, so that the capacity of the second capacitor can be restored to the required capacity while effectively The power consumption of the power supply device is controlled.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the drawings required in the prior art and the description of the embodiments of the present invention.

FIG. 1 is a first structural schematic diagram of a power supply device provided by an embodiment of the present invention;

FIG. 2 is a second structural schematic diagram of a power supply device provided by an embodiment of the present invention;

3 is a third schematic structural diagram of a power supply device provided by an embodiment of the present invention;

4 is a first schematic flowchart of a capacitive heating control method provided by an embodiment of the present invention;

5 is a second schematic flowchart of a capacitive heating control method provided by an embodiment of the present invention;

FIG. 6 is a third schematic flowchart of a capacitive heating control method provided by an embodiment of the present invention.

Detailed ways

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1 , in an embodiment of the present invention, a power supply device 100 is provided, including a voltage conversion circuit 110 , a heating control circuit 130 and a switch driving circuit 150 .

The voltage conversion circuit 110 includes a switching power supply circuit 111, a first capacitor C1 and a second capacitor C2. The switching power supply circuit 111 includes a voltage input terminal In and a voltage output terminal Out. The first terminal of the first capacitor C1 is connected to the voltage input terminal In and the voltage output terminal Out. The voltage input terminal In is electrically connected, the first terminal of the second capacitor C2 is electrically connected to the voltage output terminal Out, and the second terminal of the first capacitor C1 is electrically connected to the second terminal of the second capacitor C2. connect.

The heating control circuit 130 includes a controllable switch K, the controllable switch K is electrically connected between the voltage input terminal In and the voltage output terminal Out, and the switch driving circuit 150 is connected to the controllable switch K. The control terminal is electrically connected to output a preset switch control signal, the controllable switch K is used to conduct under the drive of the preset switch control signal, and is connected between the first capacitor C1 and the second capacitor C1. A charge and discharge loop is formed between the capacitors C2.

The charging and discharging circuit is used for conducting charging and discharging current between the first capacitor C1 and the second capacitor C2, and heating the second capacitor C2 through the charging and discharging current.

In this embodiment, the voltage conversion circuit 110 is a Boost circuit, the first capacitor C1 is an input filter capacitor of the Boost circuit, and the second capacitor C2 is an output filter capacitor of the Boost circuit. The second capacitor C2 is an electrolytic capacitor. The switching power supply circuit 111 includes an energy storage inductor L1, a first switch transistor Q1 and a second switch transistor Q2, the first end of the energy storage inductor L1 is electrically connected to the voltage input terminal In, and the energy storage inductor L1 The second end of the first switch tube Q1 is electrically connected to the first end of the first switch tube Q1 and the first end of the second switch tube Q2, and the second end of the first switch tube Q1 is connected to the first end of the first capacitor C1. The second terminal and the second terminal of the second capacitor C2 are electrically connected, and the second terminal of the second switch tube Q2 is electrically connected to the voltage output terminal Out. Wherein, the first switch transistor Q1 may be a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), and the second switch transistor Q2 may be a diode or a MOSFET. The two switching tubes Q2 are diodes, and the anode of the diode is electrically connected to the second terminal of the energy storage inductor L1, and the cathode is electrically connected to the voltage output terminal Out.

It can be understood that under low temperature conditions, the capacity of the electrolytic capacitor will be greatly reduced, which may affect the stability of the power supply device 100 . Therefore, the heating control circuit 130 including the controllable switch K is provided between the voltage input terminal In and the voltage output terminal Out of the switching power supply circuit 111, and the controllable switch K is controlled by the preset switch control signal. The switch K is turned on, thereby forming a charging and discharging loop between the first capacitor C1 and the second capacitor C2. Since the loop impedance existing in the charging and discharging loop will generate heat under the action of the current, the The discharge current is used to heat the second capacitor C2, so as to prevent the normal use of the power supply device 100 from being affected due to the large decrease in the capacity of the second capacitor C2 under low temperature conditions, so as to ensure the power supply device 100 under low temperature conditions. work efficiency.

It can be understood that as the on-time of the controllable switch K increases, the temperature of the second capacitor C2 increases gradually, and accordingly, the capacity of the second capacitor C2 also increases gradually. When the capacity of the capacitor C2 reaches a preset threshold, the switch driving circuit 150 is further configured to drive the controllable switch K to turn off according to the preset switch control signal. Further, since the capacity of the second capacitor C2 can already meet the requirements, the switching power supply circuit 111 can be controlled to enter the normal working mode. The controllable switch K may be a MOSFET or a bipolar junction transistor (Bipolar Junction Transistor, BJT).

Referring to FIG. 2 , in one embodiment, the heating control circuit 130 further includes a current limiting resistor R1 , which is connected in series with the controllable switch K to limit the amount of electricity in the charging and discharging loop. The size of the charge and discharge current. It can be understood that the size of the current limiting resistor R1 can be selected according to the current specification of the controllable switch K.

It can be understood that, in order to prevent the switch driving circuit 150 from interfering with the switching power supply circuit 111 , the switch driving circuit 150 may be configured as an isolated driving circuit.

As shown in FIG. 2 , in one embodiment, the switch driving circuit 150 may include an optocoupler 151 and a driver 153 . One end of the optocoupler 151 is electrically connected to the signal output end of the driver 153 , and the other end is electrically connected to the signal output end of the driver 153 . It is electrically connected to the control terminal of the controllable switch K, and is used for coupling the preset switch control signal output by the signal output terminal of the driver 153 to the control terminal of the controllable switch K. It can be understood that by setting the switch driving circuit 150 as an isolated driving circuit through the optocoupler 151, the switch driving circuit 150 can be effectively prevented from interfering with the switching power supply circuit 111 of the power supply device 100, thereby ensuring stability of the switching power supply circuit 111 .

In an implementation manner, the preset switch control signal can also be set to be the same as the drive signal of the first switch transistor Q1, so that the charger can be turned on while the energy storage inductor L1 stores electrical energy. The discharge loop is to complete the heating of the second capacitor C2 during the process of storing the electrical energy in the energy storage inductor L1. It can be understood that by multiplexing the driving signal of the first switch transistor Q1 to control the controllable switch K, there is no need to separately set a driving circuit for the controllable switch K, so that it is possible to prevent a separate driving circuit from affecting the controllable switch K. The interference of the switching power supply circuit 111 and the production cost of the power supply device 100 are reduced.

Referring to FIG. 3 , in an embodiment, the power supply device 100 further includes a capacitance detection circuit 170 electrically connected to the switch driving circuit 150 , and the capacitance detection circuit 170 is further connected to the first capacitor C1 It is electrically connected to the second capacitor C2 for detecting the capacity of the second capacitor C2, and when the capacity of the second capacitor C2 exceeds a preset threshold, the switch driving circuit 150 is triggered to drive the controllable Switch K is turned off.

In one embodiment, the capacitance detection circuit 170 includes a voltage detection circuit 171 and a capacitance calculation circuit 173, and the voltage detection circuit 171 is electrically connected to the first capacitor C1 and the second capacitor C2 for use in The voltage Vc1 of the first capacitor C1 is detected during the conduction period of the controllable switch K, and the voltage of the second capacitor C2 is detected at least twice, wherein the voltage of the second capacitor C2 is detected twice adjacently The time interval is a preset time interval tx, and the first voltage Vbus1 of the second capacitor C2 and the second voltage Vbus2 of the second capacitor C2 are obtained respectively, and the capacity calculation circuit 173 is used for according to the first voltage Vbus1 The capacity of the second capacitor C2 is calculated from the voltage Vc1 of the capacitor C1, the first voltage Vbus1 and the second voltage Vbus2 of the second capacitor C2, and the preset time interval tx.

It can be understood that, in an embodiment, the capacity calculation circuit 173 may include a processor (not shown), the processor triggers the voltage detection circuit 171 to detect the difference between the first capacitor C1 and the second capacitor C2 voltage, and record and detect the preset time interval tx between the first voltage Vbus1 and the second voltage Vbus2 of the second capacitor C1, and then according to the voltage Vc1 of the first capacitor C1, the voltage of the second capacitor C2 With a voltage Vbus1 and a second voltage Vbus2 and the preset time interval tx, the capacity of the second capacitor C2 is calculated, and the capacity of the second capacitor C2 is compared with a preset threshold. When the capacity of C2 is greater than or equal to the preset threshold, the switch driving circuit 150 is triggered to output a control signal for turning off the controllable switch K. It can be understood that the processor can also be electrically connected to the driving circuits (not shown) of the first switching transistor Q1 and the second switching transistor Q2, so that the output of the switching driving circuit 150 can be triggered to turn off all After the control signal of the controllable switch K is received, the switching power supply circuit 111 is controlled to enter the normal operation mode.

Specifically, when the heating control circuit 130 includes the current limiting resistor R1, within the preset time interval tx, the current I1=(VBUS-Vc1)/R1 passing through the current limiting resistor R1, wherein, VBUS is the average value of the first voltage Vbus1 and the second voltage Vbus2, or VBUS may also be approximately equal to the first voltage Vbus1 or the second voltage Vbus2. Correspondingly, within the preset time interval tx, the discharge charge of the second capacitor C2 is Q=I1*tx=(VBUS-Vc1)*tx/R1, and the voltage change of the second capacitor C2 U=Vbus1-Vbus2. According to the above conditions, the current capacitance C=(VBUS-Vc1)*tx/[R1*(Vbus1-Vbus2)] of the second capacitor C2 can be calculated. It can be understood that, if the heating control circuit 130 does not include the current limiting resistor R1 , the equivalent impedance on the heating control circuit 130 can be used instead.

It can be understood that since there will be an equivalent series resistance (ESR) in the capacitor, it should be avoided as much as possible to detect the first voltage Vbus1 of the second capacitor C2 when the controllable switch K is just turned on. To detect the first voltage Vbus1 of the second capacitor C2 when the controllable switch K is just turned on, it is necessary to subtract ESR*(VBUS-Vc1)/R1 from the first voltage Vbus1. If the voltage of the second capacitor C2 is detected at any time when the controllable switch K is just turned on, the influence of ESR need not be considered.

It can be understood that, in an implementation manner, since the second capacitor C2 discharges the first capacitor C1 through the heating control circuit 130, it can also be determined by detecting the capacity of the first capacitor C1. The capacitance of the second capacitor C1 changes. It can be understood that, for the capacity detection of the first capacitor C1, the same method as the capacity detection of the second capacitor C2 can be used. For details, reference may be made to the relevant description in the embodiment shown in FIG. 3, which will not be repeated here.

Referring to FIG. 4, in an embodiment of the present invention, a capacitive heating control method is provided, which can be applied to the power supply device 100 provided in the embodiments shown in FIG. 1 to FIG. The capacitor of the power supply device 100 performs heating control, and the capacitor heating control method at least includes the following steps:

Step 401: A heating control circuit is provided between the voltage input terminal and the voltage output terminal of the voltage conversion circuit, and the heating control circuit includes a controllable switch;

Step 402: Drive the controllable switch to conduct according to a preset switch control signal, and form a charge-discharge loop between the first capacitor and the second capacitor of the voltage conversion circuit;

Step 403: Conduct charging and discharging current between the first capacitor and the second capacitor through the charging and discharging circuit, and heat the second capacitor through the charging and discharging current.

Referring to FIG. 5, in one embodiment, the method further includes:

Step 404: Detect the capacity of the second capacitor, and when the capacity of the second capacitor exceeds a preset threshold, trigger the switch driving circuit to stop working, and the power supply device enters a normal working state.

Referring to FIG. 6, in one embodiment, the detecting the capacity of the second capacitor includes:

Step 601: Detect the voltage of the first capacitor during the conduction period of the controllable switch;

Step 602: Detect the voltage of the second capacitor at least twice during the conduction period of the controllable switch, and obtain the first voltage of the second capacitor and the second voltage of the second capacitor respectively, wherein the adjacent The time interval for detecting the voltage of the second capacitor twice is a preset time interval;

Step 603: Calculate the capacity of the second capacitor according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor, and the preset time interval.

It can be understood that the specific implementation of each step in the capacitive heating control method can also refer to the relevant descriptions in the embodiments shown in FIG. 1 to FIG. 3 , and details are not repeated here.

In the embodiment of the present invention, the power supply device and the capacitor heating control method thereof control the controllable switch in the heating control circuit to conduct through the preset switch control signal, so that the first capacitor and the first capacitor are connected to the first capacitor. A charging and discharging circuit is formed between the two capacitors. Since the charging and discharging circuit generates heat under the action of current, the second capacitor can be heated by the charging and discharging current between the first capacitor and the second capacitor. , which can effectively prevent the normal use of the power supply device from being affected by the large drop in the capacity of the second capacitor under low temperature conditions, thereby ensuring the working efficiency of the power supply device under low temperature conditions.

Claims (15)

1. A power supply device, comprising: a voltage conversion circuit and a heating control circuit;

the voltage conversion circuit comprises a switching power supply circuit, a first capacitor and a second capacitor, the switching power supply circuit comprises a voltage input end and a voltage output end, the first end of the first capacitor is electrically connected with the voltage input end, the first end of the second capacitor is connected with the voltage output end, and the second end of the first capacitor is electrically connected with the second end of the second capacitor;

the heating control circuit comprises a controllable switch, the controllable switch is electrically connected between the voltage input end and the voltage output end, the controllable switch is used for being conducted under the driving of a preset switch control signal, and a charging and discharging loop is formed between the first capacitor and the second capacitor;

the charge-discharge loop is used for conducting charge-discharge current between the first capacitor and the second capacitor and heating the second capacitor through the charge-discharge current;

the switching power supply circuit comprises an energy storage inductor, a first switching tube and a second switching tube, wherein the first end of the energy storage inductor is electrically connected with the voltage input end, the second end of the energy storage inductor is electrically connected with the first end of the first switching tube and the first end of the second switching tube, the second end of the first switching tube is electrically connected with the second end of the first capacitor and the second end of the second capacitor, and the second end of the second switching tube is electrically connected with the voltage output end.

2. The power supply apparatus of claim 1, wherein the heating control circuit further comprises a current limiting resistor connected in series with the controllable switch for limiting the magnitude of the charging and discharging current on the charging and discharging loop.

3. The power supply device according to claim 1 or 2, further comprising a switch driving circuit electrically connected to the control terminal of the controllable switch, for outputting the preset switch control signal and driving the controllable switch to be turned on or off according to the preset switch control signal.

4. The power supply device according to claim 3, wherein the switch driving circuit is an isolated driving circuit.

5. The power supply device according to claim 3, wherein the switch driving circuit comprises an optical coupler and a driver, one end of the optical coupler is electrically connected to the signal output terminal of the driver, and the other end of the optical coupler is electrically connected to the control terminal of the controllable switch, for coupling a preset switch control signal output from the signal output terminal of the driver to the control terminal of the controllable switch.

6. The power supply device according to any one of claims 1 to 2, wherein the preset switch control signal is the same as a driving signal of the first switching tube.

7. The power supply device according to claim 3, wherein the predetermined switch control signal is the same as a driving signal of the first switching tube.

8. The power supply device according to claim 4, wherein the predetermined switch control signal is the same as a driving signal of the first switching tube.

9. The power supply device according to claim 5, wherein the predetermined switch control signal is the same as a driving signal of the first switching tube.

10. The power supply device according to claim 3, further comprising a capacitance detection circuit electrically connected to the switch driving circuit, wherein the capacitance detection circuit is further electrically connected to the first capacitor and the second capacitor, and configured to detect a capacitance of the second capacitor, and when the capacitance of the second capacitor exceeds a preset threshold, trigger the switch driving circuit to stop operating, and the power supply device enters a normal operating state.

11. The power supply apparatus according to claim 10, wherein the capacitance capacity detection circuit includes a voltage detection circuit and a capacity calculation circuit, the voltage detection circuit is electrically connected to the first capacitor and the second capacitor, and is configured to detect a voltage of the first capacitor during the conduction period of the controllable switch and detect a voltage of the second capacitor at least twice, wherein a time interval between two adjacent times of detecting the voltage of the second capacitor is a preset time interval, and obtain a first voltage of the second capacitor and a second voltage of the second capacitor, respectively, and the capacity calculation circuit is configured to calculate the capacity of the second capacitor according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor, and the preset time interval.

12. A power supply device, comprising: a voltage conversion circuit and a heating control circuit;

the voltage conversion circuit comprises a switching power supply circuit, a first capacitor and a second capacitor, the switching power supply circuit comprises a voltage input end and a voltage output end, the first end of the first capacitor is electrically connected with the voltage input end, the first end of the second capacitor is connected with the voltage output end, and the second end of the first capacitor is electrically connected with the second end of the second capacitor;

the heating control circuit comprises a controllable switch, the controllable switch is electrically connected between the voltage input end and the voltage output end, the controllable switch is used for being conducted under the driving of a preset switch control signal, and a charging and discharging loop is formed between the first capacitor and the second capacitor;

the charge-discharge loop is used for conducting charge-discharge current between the first capacitor and the second capacitor and heating the second capacitor through the charge-discharge current;

the power supply device further comprises a switch driving circuit, wherein the switch driving circuit is electrically connected with the control end of the controllable switch and is used for outputting the preset switch control signal and driving the controllable switch to be switched on or switched off according to the preset switch control signal;

the power supply device further comprises a capacitance capacity detection circuit electrically connected with the switch driving circuit, the capacitance capacity detection circuit is further electrically connected with the first capacitor and the second capacitor and is used for detecting the capacity of the second capacitor, when the capacity of the second capacitor exceeds a preset threshold value, the switch driving circuit is triggered to stop working, and the power supply device enters a normal working state;

the capacitance capacity detection circuit comprises a voltage detection circuit and a capacity calculation circuit, the voltage detection circuit is electrically connected with the first capacitor and the second capacitor and is used for detecting the voltage of the first capacitor during the conduction period of the controllable switch and detecting the voltage of the second capacitor at least twice, the time interval of the voltage of the second capacitor detected twice is a preset time interval, the first voltage of the second capacitor and the second voltage of the second capacitor are obtained respectively, and the capacity calculation circuit is used for calculating the capacity of the second capacitor according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor and the preset time interval.

13. A capacitance heating control method of a power supply device according to any one of claims 1 to 12, comprising:

a heating control circuit is arranged between a voltage input end and a voltage output end of the voltage conversion circuit, and the heating control circuit comprises a controllable switch;

driving the controllable switch to be conducted according to a preset switch control signal, and forming a charge-discharge loop between a first capacitor and a second capacitor of the voltage conversion circuit;

and conducting charge-discharge current between the first capacitor and the second capacitor through the charge-discharge loop, and heating the second capacitor through the charge-discharge current.

14. The method of claim 13, wherein in the case where the power supply device further comprises a switch drive circuit, the method further comprises: and detecting the capacity of the second capacitor, and triggering the switch driving circuit to stop working when the capacity of the second capacitor exceeds a preset threshold value, so that the power supply device enters a normal working state.

15. The method of claim 14, wherein said detecting the capacitance of the second capacitor comprises:

detecting a voltage of the first capacitance during the conduction of the controllable switch;

detecting the voltage of the second capacitor at least twice during the conduction period of the controllable switch to obtain a first voltage of the second capacitor and a second voltage of the second capacitor respectively, wherein the time interval of detecting the voltage of the second capacitor twice is a preset time interval;

and calculating the capacity of the second capacitor according to the voltage of the first capacitor, the first voltage and the second voltage of the second capacitor and the preset time interval.

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