CN106160195A - A kind of management of power use method and system - Google Patents

Abstract

The invention discloses a kind of management of power use method and system.This system includes control module, AC/DC modular converter.Control module includes processor, electric voltage observation circuit, power source switching circuit, output voltage switching circuit, direct current input interface, exchange input interface, direct current output interface and exchanges output interface；AC/DC modular converter includes AC/DC change-over circuit, DC reduction voltage circuit；Direct current output interface is connected with the input of DC reduction voltage circuit, and exchange output interface is connected with the input of AC/DC change-over circuit, and processor is connected with feedback circuit.These management of power use method and system can save the DC-AC conversion devices such as the Switching Power Supply that is equipped with for each direct-flow electricity utilization apparatus, can use unidirectional current produced by clean energy resource simultaneously, reduce the resource consumption of society.

Description

Method and system for managing power consumption

technical field

The invention relates to the field of electrical switches, in particular to a power consumption management method and system.

Background technique

At present, LED lamps for energy saving and consumption reduction have entered ordinary households. The brightness of tens of watts of energy-saving lamps can be achieved by LED lamps of tens of watts or even a few watts. Compared with current light bulbs and energy-saving lamps, LED lamps Its service life is particularly long, usually up to 5 to 10 years. However, LED lamps use a low-voltage DC power supply, so each LED lamp needs to be equipped with a dedicated AC/DC conversion device when in use; at the same time, mobile phones, cameras and other low-voltage power supply devices need to be equipped with AC/DC conversion devices when charging.

The current air switch is divided into AC air switch and DC air switch. The AC air switch is used to protect AC electrical equipment, and the DC air switch is used to protect DC electrical equipment. The outlet current of the commonly used AC air switch is still AC, and the air switch with AC-DC direct conversion has not been found yet. In this way, a lot of DC power equipment needs to use a separate set of AC-DC conversion circuit, which not only increases the cost of related equipment, but also increases the potential safety hazard due to the existence of AC power.

Contents of the invention

In order to solve the problem of low-cost and low-risk power supply for DC power equipment in the prior art, the present invention provides a power management method and system.

According to the first aspect of the present invention, a power management system is provided, the power management system includes a control module, an AC/DC conversion module,

The control module includes a processor, a voltage monitoring circuit, a power supply switching circuit, an output voltage switching circuit, a DC input interface, an AC input interface, a DC output interface, and an AC output interface. The processor is connected to the voltage monitoring circuit, The power supply switching circuit is connected to the output voltage switching circuit, and the voltage monitoring circuit is connected to the DC input interface;

The AC/DC conversion module includes an AC-DC conversion circuit and a DC-DC step-down circuit, the output end of the AC-DC conversion circuit is connected to the input end of the DC-DC step-down circuit, and the DC-DC step-down circuit The step-down circuit includes a feedback circuit;

The DC output interface is connected to the input end of the DC-DC step-down circuit, the AC output interface is connected to the input end of the AC-DC conversion circuit, and the processor is connected to the feedback circuit;

The processor is used to judge whether the voltage detected by the voltage monitoring circuit input by the DC input interface reaches or exceeds the voltage threshold, and if so, controls the input end of the power supply switching circuit to be connected to the DC input interface, and controls The output terminal of the output voltage switching circuit is connected to the DC output interface; otherwise, the input terminal of the power supply switching circuit is controlled to be connected to the AC input interface, and the output terminal of the output voltage switching circuit is controlled to be connected to the AC output interface connection;

The feedback circuit is used for receiving a set voltage from the processor, and adjusting the output voltage value of the DC-DC step-down circuit to the set voltage.

Wherein, the DC-DC step-down circuit further includes a power conversion circuit and a rectification filter circuit, the output end of the power conversion circuit is connected to the input end of the rectification filter circuit, and the output end of the rectification filter circuit is connected to the The input terminal of the feedback circuit is connected, and the output terminal of the feedback circuit is connected with the control terminal of the power conversion circuit.

Wherein, the feedback circuit includes a sampling circuit, an error amplifier circuit, and a PWM control circuit connected in sequence, the input end of the sampling circuit is the input end of the feedback circuit, and the output end of the PWM control circuit is the feedback circuit The output terminal of the PWM control circuit is connected with the processor.

Wherein, the power conversion circuit is an LLC series resonant converter, and the rectification and filtering circuit is a MOS transistor rectification circuit.

Wherein, the AC-DC conversion circuit includes a lightning protection circuit, a filter circuit, a rectification and voltage stabilization circuit, and a power factor correction circuit connected in sequence, and the input terminal of the lightning protection circuit is the input of the AC-DC conversion circuit The output end of the power factor correction circuit is the output end of the AC-DC conversion circuit.

Wherein, the control module further includes a first communication circuit for communicating with an external control device, and the first communication circuit is connected to the processor.

Wherein, the power consumption management system further includes a touch screen, and the control module further includes a second communication circuit for communicating with the touch screen, and the second communication circuit is connected to the processor.

Wherein, the control module further includes an acousto-optic circuit, and the acousto-optic circuit is connected with the processor.

Wherein, the power consumption management system further includes an AC/AC air switch, the control module further includes a second AC output interface connected to the input end of the AC/AC air switch, and the processor is also used to When the AC output voltage is selected, the input terminal of the power supply switching circuit is controlled to be connected to the AC input interface, and the output terminal of the output voltage switching circuit is controlled to be connected to the second AC output interface.

According to a second aspect of the present invention, there is provided a method for managing electricity consumption, the method comprising the following steps:

Monitor whether the voltage of the DC power supply reaches or exceeds the voltage threshold;

If so, connect the DC power supply; otherwise connect the AC power supply, and convert the AC voltage of the connected AC power supply into a DC voltage;

The DC voltage of the DC power supply or the converted DC voltage of the AC power supply is reduced to a set voltage and output.

The electricity consumption management method and system in the present invention directly convert alternating current into direct current and output it to the power supply line for use by low-voltage electrical equipment; or directly use direct current generated by clean energy, such as solar energy and hydroelectric power, as direct current power supply. In this way, it is not only possible to save AC-DC conversion devices such as switching power supplies for each DC power device, but also to use DC power generated by clean energy to reduce social resource consumption. In addition, due to the low-voltage power supply, there will be no hidden danger of electric shock to the human body.

Description of drawings

The drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is a block diagram of the power consumption management system according to the present invention;

Fig. 2 is a structural diagram of the AC/DC conversion module 12 according to the present invention;

Fig. 3 is the circuit diagram of power conversion circuit and rectification filter circuit according to the present invention;

Fig. 4 is a block diagram of a control module according to the present invention;

Fig. 5 is a flow chart of the electricity management method according to the present invention;

Fig. 6 is a flow chart of a specific embodiment of the power consumption management method according to the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

The invention provides a power consumption management system, which can be integrated with a common AC air switch.

Fig. 1 is a block diagram of a power consumption management system according to the present invention. As shown in FIG. 1 , the power consumption management system includes a control module 11 and an AC/DC conversion module 12 . Wherein, the control module 11 includes a processor 111 , a voltage monitoring circuit 112 , a power supply switching circuit 113 , an output voltage switching circuit 114 , a DC input interface 115 , an AC input interface 116 , a DC output interface 117 and an AC output interface 118 . The processor 111 is respectively connected to a voltage monitoring circuit 112 , a power supply switching circuit 113 , and an output voltage switching circuit 114 , and the voltage monitoring circuit 112 is connected to a DC input interface 115 .

The AC/DC conversion module 12 includes an AC-DC conversion circuit 121 and a DC-DC step-down circuit 122 . The output end of the AC-DC conversion circuit 121 is connected to the input end of the DC-DC step-down circuit 122 . The DC-DC step-down circuit 122 includes a feedback circuit 123 . The DC output interface 117 is connected to the input end of the DC-DC step-down circuit 122 , the AC output interface 118 is connected to the input end of the AC-DC conversion circuit 121 , and the processor 111 is connected to the feedback circuit 123 .

The voltage monitoring circuit 112 monitors the voltage of the DC power supply through the DC input interface 115 , and sends the monitored DC voltage to the processor 111 . The processor 111 judges whether the voltage detected by the voltage monitoring circuit 112 reaches or exceeds a set voltage threshold, for example, the voltage threshold can be set to, for example, 30V, 24V, 12V and so on. If the voltage threshold is reached or exceeded, the processor 111 controls the input end of the power supply switching circuit 113 to be connected to the DC input interface 115, that is, the DC power supply that reaches or exceeds the voltage threshold is connected to the power consumption management system to provide power for DC power equipment , while controlling the output terminal of the output voltage switching circuit 114 to be connected to the DC output interface 117 . If it is less than the threshold voltage, the processor 111 controls the input end of the power supply switching circuit 113 to be connected to the AC input interface 116, that is, the AC power supply supplies power for the DC electric equipment, and simultaneously controls the output voltage switching circuit 114. The output terminal and the AC output Interface 118 is connected. It can be seen that the power supply switching circuit 113 is optionally connected to the DC input interface 115 and the AC input interface 116 , and the output voltage switching circuit 114 is optionally connected to the DC output interface 117 and the AC output interface 118 .

In this way, when the voltage of the DC power supply is insufficient, it can automatically switch to the AC power supply for power supply. It should be noted that the DC power supply here can be a traditional storage battery, or a DC power supply generated by clean energy, such as solar energy, hydroelectric power, etc., and multiple DC power supplies can be used in parallel.

The feedback circuit 123 is connected to the processor 111 of the control module 11, so as to receive the user's set voltage from the processor 111, and adjust the output voltage value of the DC-DC step-down circuit 122 to the user's set voltage, so as to control the DC voltage. Electrical equipment is supplied with power. The specific structure of the DC-DC step-down circuit 122 and the specific structure of the feedback circuit 123 will be referred to later to describe in detail how to adjust the DC voltage input to the DC-DC step-down circuit 122 to a user-set voltage.

FIG. 2 is a structural diagram of the AC/DC conversion module 12 according to the present invention. As shown in FIG. 2 , the DC-DC step-down circuit 122 also includes a power conversion circuit 1221 and a rectification and filtering circuit 1222 . Wherein, the output end of the power conversion circuit 1221 is connected to the input end of the rectification filter circuit 1222, the output end of the rectification filter circuit 1222 is connected to the input end of the feedback circuit 123, and the output end of the feedback circuit 123 is connected to the control end of the power conversion circuit 1221 . That is, the power conversion circuit 1221 has a control terminal besides the input terminal and the output terminal, so as to adjust the output voltage through the control terminal.

The specific circuit structure of the power conversion circuit 1221 is shown in FIG. 3 . Wherein, the power conversion circuit 1221 is an LLC series resonant converter. In Figure 3, IC1 is the driver chip, R1 and R2 are the driver resistors, M1 and M3 are MOS tubes, C1 is the resonant capacitor, L1 is the resonant inductor, T1 is the EE65 transformer, and D1\E1 form the rectification and voltage stabilization circuit, which is the chip’s work supply VCC. The resonant circuit can realize the zero-voltage conduction of the MOS tube, greatly reduces the conduction loss, and can transmit power up to 1KW. Since there is no switching loss, the switching frequency can be increased, thereby reducing the size of the magnetic components and the capacity of the filter capacitor, which greatly reduces the cost. Typically, the LLC series resonant converter can output 36V/30A power. Of course, the user can choose the output DC power supply voltage according to actual needs.

The specific circuit structure of the rectification and filtering circuit 1222 is shown in FIG. 3 . Wherein, the rectification and filtering circuit 1222 includes rectification MOS transistors M2 and M4. Due to the large output current, the use of ordinary diode rectification method will cause greater loss, so the MOS tube is used instead of the diode, and the synchronous rectification method is used to realize the zero-current shutdown of M2 and M4, which greatly reduces the turn-off loss.

Referring to FIG. 2 again, the feedback circuit 123 includes a sampling circuit 1225 , an error amplifier circuit 1224 , and a PWM control circuit 1223 connected in sequence. The input terminal of the sampling circuit 1225 is the input terminal of the feedback circuit 123 , and the output terminal of the PWM control circuit 1223 is the output terminal of the feedback circuit 123 . The adjustment terminal of the PWM control circuit 1223 is connected to the processor 111 to receive a user's set voltage from the processor 111 .

Here, the feedback circuit 123 is also used to stabilize the output of the system, and when abnormal conditions such as overvoltage, overcurrent, and undervoltage are detected, the gate voltage of the MOS transistor in the rectification and filtering circuit 1222 is disconnected in time to Turn off the MOS tube and stop the output.

In addition, when adjusting the output DC voltage value according to the user's set voltage, the PWM control circuit 1223 adjusts the pulse duty cycle according to the set voltage received from the processor 111 at its adjustment terminal, and then adjusts the output voltage. The adjusted output voltage range can be 0-24V to meet the requirements of different loads.

In Fig. 1 and Fig. 2, only one DC-DC step-down circuit 122 is shown. In actual use, multiple DC-DC step-down circuits can be set in the power consumption management system, so as to respond to the needs of different DC Multiple DC consumers of the supply voltage are powered. Wherein each DC-DC step-down circuit can adopt a BUCK step-down method, and adopt voltage feedback and current feedback methods in the feedback circuit to stabilize the output.

Referring again to FIG. 2 , the AC-DC conversion circuit 121 includes a lightning protection circuit 1211 , a filter circuit 1212 , a rectification and stabilization circuit 1213 , and a power factor correction circuit 1214 connected in sequence. The input end of the lightning protection circuit 1211 is the input end of the AC-DC conversion circuit 121 , and the output end of the power factor correction circuit 1214 is the output end of the AC-DC conversion circuit 121 .

The lightning protection circuit 1211 is used to resist high-voltage pulses and surge currents to protect subsequent circuits, and may specifically include fuses, NTC resistors, varistors, and air discharge tubes. The filter circuit 1212 may be an EMI filter circuit for preventing and suppressing electromagnetic interference, and may specifically include X capacitors, Y capacitors, common-mode inductors, differential-mode inductors, and the like. The rectifying and stabilizing circuit 1213 is used to convert alternating current into direct current, and may specifically include a rectifying bridge, an electrolytic capacitor, a CBB capacitor, and the like. The power factor correction circuit 1214 is used for power factor correction to force the phase of the current to be close to the voltage. This is because charging the electrolytic capacitor during rectification will cause a phase shift between the voltage and the current and generate reactive power.

FIG. 4 shows a block diagram of the control module 11 according to the present invention. Wherein, the control module 11 further includes a first communication circuit 1191 for communicating with an external control device, and the first communication circuit 1191 is connected with the processor 111 . The external control device can be a wireless control device such as a mobile phone or a remote controller, or a wired control device such as a wire controller to control the power consumption management system. At the same time, the power consumption management system can also send its operating status to the external control device for display thereon. The first communication circuit 1191 can communicate with an external control device through a UART communication mode, and this communication can be wired communication or wireless communication. The specific work is that the external control device transmits the user's set voltage to the controller 111 through the first communication circuit 1191, and the controller 111 transmits the set voltage to the feedback circuit 123 to convert the output DC voltage value.

In addition, the power consumption management system further includes a touch screen, and the control module 11 includes a second communication circuit 1192 communicating with the touch screen, and the second communication circuit 1192 is connected to the processor 111 . The touch screen transmits the set voltage input by the user to the controller 111 through the second communication circuit 1192 , and the controller 111 transmits the set voltage to the feedback circuit 123 to convert the output DC voltage value. At the same time, the controller can also transmit relevant status information to the touch screen through the second communication circuit 1192 for display.

It should be noted that the information transmitted from the external control device and the touch screen to the processor 111 includes but is not limited to the voltage set by the user, and may also include related parameter settings and the like.

The control module 11 also includes an acousto-optic circuit 1193 connected to the processor 111 . When an abnormal situation occurs, such as an oversized circuit or a short circuit, the processor 111 notifies the acousto-optic circuit 1193 to respond to remind the user to take corresponding processing operations.

In addition, the control module also includes an abnormality monitoring circuit, which is connected to the processor 111. When the current is too large, short-circuited, etc., the processor 111 controls the power supply switching circuit 113 to disconnect the DC input interface 115 and the AC input. Interface 116 connection.

The power consumption management system also includes an AC/AC air switch, the control module 11 also includes a second AC output interface connected to the input end of the AC/AC air switch, and the processor is also used to control the power supply when the user selects the AC output voltage The input end of the power switching circuit is connected to the AC input interface, and the output end of the control output voltage switching circuit is connected to the second AC output interface. That is, when the user chooses to supply power to the AC power device, the processor is notified, and the processor controls to transmit the input AC power to the AC/AC air switch, so that the AC/AC air switch provides power for the AC power device.

The overall size of the AC/DC conversion module of the present invention is substantially the same as that of the AC air switch, which is convenient for assembly together with the AC air switch.

The invention also discloses a power consumption management method. Referring to Figure 5, the method includes:

Monitor whether the voltage of the DC power supply reaches or exceeds the voltage threshold;

If so, connect the DC power supply; otherwise connect the AC power supply, and convert the AC voltage of the connected AC power supply into a DC voltage;

Reduce the DC voltage of the DC power supply or the converted DC voltage of the AC power supply to a set voltage and output it.

It should be noted that when the set voltage fed back from the feedback circuit is not received, the DC voltage of the DC power supply or the converted DC voltage of the AC power supply is directly output.

Fig. 6 shows a specific embodiment of the power consumption management method of the present invention. The description is as follows:

Step 601, power on the system;

Step 602, after power-on, the system reads the previously configured parameters, such as the power supply voltage of the output port of the AC/DC conversion module, version and model, etc.;

Step 603, initialize relevant variables;

Step 604, detect whether the DC power supply voltage reaches or exceeds the set threshold value, when it is detected that the DC power supply voltage reaches or exceeds the threshold value, execute step 606, otherwise execute step 605;

Step 605, switch to the AC/DC conversion module for power supply, convert the connected alternating current into direct current, and then execute step 606;

Step 606, judge whether the user has set the set voltage, if set, then execute step 607, if not, execute step 608;

Step 607, convert the DC power supply voltage into a set voltage, and execute step 608;

Step 608, supplying power directly according to the DC power supply voltage, and displaying communication-related messages;

Step 609, judging whether there are parameter settings, buttons, etc., so as to perform parameter setting, control execution and other processing, if there is, execute step 610, if not, execute step 612;

Step 610, perform button processing;

Step 611, data storage;

Step 612, judging whether UART (Universal Asynchronous Receiver Receiver) communication is required, if necessary, execute step 613, otherwise execute step 614;

Step 613, carry out UART communication, mainly process the serial port data sent by the wireless and wired communication modules, so as to realize the control of the intelligent power consumption management air switch by wireless devices such as mobile phones, remote controllers, and wired devices such as wire controllers, and at the same time related operation The status is sent to display devices such as mobile phones;

Step 614, perform power-saving processing;

Step 615, performing sound and light processing, which is mainly used to remind the user to take corresponding actions when an abnormality occurs;

Step 616, perform exception processing, mainly referring to processing such as cutting off the power supply when overcurrent, short circuit, etc. occur.

Using the power consumption management system and method of the present invention, the alternating current is directly converted into direct current and output to the power supply line for use by low-voltage electrical equipment; or the direct current generated by clean energy, such as solar energy and hydroelectric power, is directly used as direct current power supply. In this way, it is not only possible to save AC-DC conversion devices such as switching power supplies for each DC power device, but also to use DC power generated by clean energy to reduce social resource consumption. In addition, due to the low-voltage power supply, there will be no hidden danger of electric shock to the human body. When the power consumption management system is integrated with the traditional AC air switch, it can simultaneously supply power to different electrical equipment that requires AC power and DC power, reducing the cost and the risk of potential safety hazards.

The content described above can be implemented alone or combined in various ways, and these variants are all within the protection scope of the present invention.

It should be noted that, in this document, the terms "comprising", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements, but also includes none. other elements specifically listed, or also include elements inherent in the article or equipment. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the article or device comprising said element.

The above embodiments are only used to illustrate the technical solutions of the present invention rather than limit them, and the present invention is described in detail with reference to preferred embodiments. Those skilled in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and all should be covered by the claims of the present invention.

Claims (10)

1. A power management system, characterized in that, the power management system includes a control module, an AC/DC conversion module, The control module includes a processor, a voltage monitoring circuit, a power supply switching circuit, an output voltage switching circuit, a DC input interface, an AC input interface, a DC output interface, and an AC output interface. The processor is connected to the voltage monitoring circuit, The power supply switching circuit is connected to the output voltage switching circuit, and the voltage monitoring circuit is connected to the DC input interface; The AC/DC conversion module includes an AC-DC conversion circuit and a DC-DC step-down circuit, the output end of the AC-DC conversion circuit is connected to the input end of the DC-DC step-down circuit, and the DC-DC step-down circuit The step-down circuit includes a feedback circuit; The DC output interface is connected to the input end of the DC-DC step-down circuit, the AC output interface is connected to the input end of the AC-DC conversion circuit, and the processor is connected to the feedback circuit; The processor is used to judge whether the voltage detected by the voltage monitoring circuit input by the DC input interface reaches or exceeds a voltage threshold, and if so, controls the input end of the power supply switching circuit to be connected to the DC input interface, And control the output end of the output voltage switching circuit to connect to the DC output interface, otherwise control the input end of the power supply switching circuit to connect to the AC input interface, and control the output end of the output voltage switching circuit to connect to the The AC output interface is connected; The feedback circuit is used for receiving a set voltage from the processor, and adjusting the output voltage value of the DC-DC step-down circuit to the set voltage. 2. The power consumption management system according to claim 1, wherein the DC-DC step-down circuit further comprises a power conversion circuit, a rectification filter circuit, and the output terminal of the power conversion circuit is connected to the rectification filter circuit The input end of the rectification and filtering circuit is connected to the input end of the feedback circuit, and the output end of the feedback circuit is connected to the control end of the power conversion circuit. 3. The power consumption management system as claimed in claim 2, wherein the feedback circuit comprises a sampling circuit, an error amplifier circuit, and a PWM control circuit connected in sequence, and the input terminal of the sampling circuit is an input terminal of the feedback circuit. The input terminal, the output terminal of the PWM control circuit is the output terminal of the feedback circuit, and the adjustment terminal of the PWM control circuit is connected with the processor. 4. The power consumption management system according to claim 2, wherein the power conversion circuit is an LLC series resonant converter, and the rectification and filtering circuit is a MOS transistor rectification circuit. 5. The power consumption management system according to claim 2, wherein the AC-DC conversion circuit includes a lightning protection circuit, a filter circuit, a rectification and voltage stabilization circuit, and a power factor correction circuit connected in sequence, and the protection circuit The input end of the lightning protection circuit is the input end of the AC-DC conversion circuit, and the output end of the power factor correction circuit is the output end of the AC-DC conversion circuit. 6. The power consumption management system according to claim 3, wherein the control module further comprises a first communication circuit for communicating with an external control device, and the first communication circuit is connected to the processor. 7. The power consumption management system according to claim 1, wherein the power consumption management system further comprises a touch screen, and the control module further comprises a second communication circuit for communicating with the touch screen, and the first The second communication circuit is connected with the processor. 8. The power consumption management system according to claim 1, wherein the control module further comprises an acousto-optic circuit, and the acousto-optic circuit is connected to the processor. 9. The power consumption management system according to any one of claims 1-8, wherein the power consumption management system also includes an AC/AC air switch, and the control module also includes a The input end of the air switch is connected to the second AC output interface, and the processor is also used to control the input end of the power supply switching circuit to be connected to the AC input interface when the user selects the AC output voltage, and to control the The output terminal of the output voltage switching circuit is connected to the second AC output interface. 10. A method for managing electricity consumption, characterized in that the method comprises the following steps: Monitor whether the voltage of the DC power supply reaches or exceeds the voltage threshold; If so, connect the DC power supply; otherwise connect the AC power supply, and convert the AC voltage of the connected AC power supply into a DC voltage; The DC voltage of the DC power supply or the converted DC voltage of the AC power supply is reduced to a set voltage and output.