DC battery charging device and charging method

Abstract

The present invention provides a DC battery charging device, comprising a power connection structure, a battery charging interface and a single-phase three-winding transformer, wherein the three windings of the single-phase three-winding transformer are respectively a first winding, a second winding and a third winding, the same-name end of the first winding is connected to the positive pole of the power connection structure, the negative pole of the power connection structure and the same-name end of the second winding are both grounded, and the opposite-name end of the third winding is connected to the negative pole of the battery charging interface; the charging power supply of the present invention is easy to obtain, and can be obtained from the mains after simple rectification, or a battery pack can be used as a charging power supply to realize charging of a high-voltage battery pack; the entire device has only one fully-controlled power switch, and the rest are composed of relatively low-voltage diodes, transistors, PMOS tubes and voltage regulator tubes, capacitors and resistors, with a small size, low cost and easy maintenance; charging is performed by circuit self-excitation, without a separate control loop and complex control chip, without the need for a control power supply, and with high reliability.

Description

Technical Field

[0001] The present invention relates to the field of power devices, and in particular to a direct current battery charging device and a charging method. Background Art

[0002] Batteries are a common means of storing electrical energy. With the rapid development of battery energy storage power stations and various new energy power stations, high-voltage DC battery packs with rated voltages ranging from 500V to 1500V are increasingly being used. Current DC battery chargers are complex and bulky. Charging high-voltage battery packs with rated voltages above 500V, in particular, often requires complex charging devices with converters, complex control systems, and demanding external power supply requirements. Therefore, high-voltage DC battery packs are often charged in the factory. However, at the construction site, some spare battery packs, or those assembled after troubleshooting, are not directly connected to the grid for reliability reasons and often require separate charging on-site. Furthermore, the available charging power sources on-site are generally 220V AC or DC, making it difficult to directly charge 500V to 1500V batteries.

[0003] Therefore, it is necessary to study a simple charging device that has low requirements for input power and is easy to obtain. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a DC battery charging device and charging method, which can solve the problem that the charging power supply at the construction site is generally 220V AC or DC, and it is difficult to directly charge 500V to 1500V batteries.

[0005] To this end, the present invention adopts the following technical solutions:

[0006] A DC battery charging device includes a power connection structure, a battery charging interface, and a single-phase three-winding transformer. The three windings of the single-phase three-winding transformer are respectively a first winding, a second winding, and a third winding. The same-name end of the first winding is connected to the positive pole of the power connection structure, the negative pole of the power connection structure and the same-name end of the second winding are both grounded, and the opposite-name end of the third winding is connected to the negative pole of the battery charging interface.

[0007] A full-controlled power switch is provided between the opposite-name end of the winding and the ground, the positive electrode of the full-controlled power switch is connected to the opposite-name end of the first winding, and the negative electrode of the full-controlled power switch is grounded. A first resistor, a sixth resistor, and a second capacitor are sequentially connected in series between the power connection structure and the second winding, the negative electrode of the second capacitor is connected to the opposite-name end of the winding, and the control end of the full-controlled power switch is connected between the first resistor and the sixth resistor. The potential point of the control end of the full-controlled power switch is assumed to be a first potential point;

[0008] The opposite-name end of the second winding is connected to the cathode of the second diode, the same-name end of the second winding is connected to the positive electrode of the first capacitor, the negative electrode of the first capacitor is connected to the positive electrode of the second diode, the negative electrode of the first capacitor is connected in series with a fifth resistor, a fourth resistor, and a second voltage-stabilizing diode in sequence, the negative electrode of the second voltage-stabilizing diode is grounded, the negative electrode of the first capacitor is also connected to the emitter of a transistor, the base of the transistor is connected between the fifth resistor and the fourth resistor, the collector of the transistor is connected in series with a third resistor and a second resistor in sequence, one end of the second resistor is connected between the first resistor and the sixth resistor, the control end of the fully-controlled power switch is connected to the source of a PMOS transistor, the drain of the PMOS transistor is grounded, and the gate of the PMOS transistor is connected between the third resistor and the second resistor. The potential point of the gate of the PMOS transistor is set as the second potential point, the potential point of the negative electrode of the first capacitor is set as the third potential point, and the potential point of the base of the transistor is set as the fourth potential point;

[0009] A third diode is connected in series between the same-name end of the third winding and the battery charging interface, the positive electrode of the third diode is connected to the same-name end of the third winding, and the negative electrode of the third diode is connected to the positive electrode of the battery charging interface. A fourth capacitor is connected in parallel between the positive and negative electrodes of the battery charging interface, and the positive electrode of the fourth capacitor is connected to the positive electrode of the battery charging interface.

[0010] On the basis of adopting the above technical solutions, the present invention may also adopt the following further technical solutions, or use these further technical solutions in combination:

[0011] A first diode and a seventh resistor are sequentially connected in series between the opposite-name end and the same-name end of the first winding, a third capacitor is connected in parallel at both ends of the seventh resistor, an anode of the first diode is connected to the opposite-name end of the first winding, a cathode of the first diode is connected to the positive electrode of the third capacitor, and a cathode of the third capacitor is connected to the positive electrode of the power connection structure;

[0012] A first voltage regulator tube is connected in series between the gate of the PMOS tube and the positive electrode of the second capacitor. The positive electrode of the first voltage regulator tube is connected to the gate of the PMOS tube. The potential point of the positive electrode of the second capacitor is set as the fifth potential point.

[0013] The trigger value of the full-control power switch is 23V to 25V.

[0014] The breakdown voltage of the voltage regulator tube is the same as that of the voltage regulator tube, which is in the range of 30 to 35V.

[0015] Assume that the voltage connected to the power connection structure is U0, and the winding ratio of the three-winding transformer is k1 / k2=U0 / 24; K3 / K1=10-30.

[0016] The capacitance ratio of the capacitor to the capacitor is 2:1.

[0017] Assume that the voltage connected to the power connection structure is U0, and the voltage U0 ranges from 110V to 400V.

[0018] The present invention also provides a method for charging a DC battery, including the following working states and workflow:

[0019] When the power connection structure is not connected to the circuit, the fully controlled power switch, PMOS tube, and transistor are all in the off state in the initial state;

[0020] When the power connection structure with a voltage of U0 is connected to the circuit and generates current, a small current loop is formed through the first resistor, the sixth resistor, the second capacitor, and the second winding in sequence, thereby raising the potential of the first potential point until it reaches the trigger value of the full-controlled power switch, thereby turning on the full-controlled power switch. At this time, the current forms a power-on loop through the first winding and the full-controlled power switch, thereby charging the first winding. At the same time, the third winding generates an induced current, which passes through the third diode and the battery charging interface to charge the DC battery.

[0021] At this time, the current in the second winding passes through the first capacitor and the second diode in sequence to form a loop, thereby charging the first capacitor. At this time, the potential of the positive electrode of the first capacitor and the potential of the same-name end of the second winding are both ground potential. According to the current flow direction, the third potential point will generate a negative potential. Since the potential of the negative electrode of the second Zener diode is ground potential, when the potential of the third potential point is lower than the conduction value of the second Zener diode, the second Zener diode is turned on, and the current passes through the second Zener diode, the fourth resistor, the fifth resistor, and the third potential point in sequence. At this time, the potential of the fourth potential point is higher than the third potential point, causing the transistor to turn on, and the potential of the second potential point decreases. At this time, the potential of the second potential point is lower than the potential of the first potential point, causing the PMOS tube to turn on. The potential of the first potential point causes the full-controlled power switch to turn off, and charging of the first winding stops;

[0022] When the fully controlled power switch is turned off, the power connection structure disconnects the circuit, and the residual current in the first winding passes through the first diode, the seventh resistor, and the third capacitor in sequence until the current in the first winding drops to zero;

[0023] The current in the second winding decays as the current in the first winding decays. At this time, the current in the second winding is generated by the charge in the second capacitor flowing through the second winding to the ground. This process causes the potential of the fifth potential point to increase. When the potential difference between the fifth potential point and the second potential point exceeds the breakdown voltage of the first voltage regulator tube, the first voltage regulator tube reversely breaks down, and the current of the second capacitor charging the first capacitor through the third resistor and the transistor increases rapidly. The potential of the third potential point increases rapidly, and the potential of the fourth potential point also increases accordingly. The second voltage regulator tube returns to the off state, and the transistor is subsequently turned off. The potential of the second potential point increases, and the PMOS tube is turned off.

[0024] After the PMOS tube is turned off, the potential at the first potential point increases, and the fully controlled power switch is turned on again, entering the next charging cycle.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] 1. The charging power source is easy to obtain. It can be obtained from the mains electricity through simple rectification, or the battery pack can be used as the charging power source to charge the high-voltage battery pack and the high-voltage capacitor;

[0027] 2. The entire device has only one fully controlled power switch, and the rest are composed of low-voltage diodes, transistors, PMOS tubes and voltage regulator tubes, capacitors and resistors at low prices. It is small in size, low in cost and easy to maintain.

[0028] 3. It uses circuit self-excitation for charging, without separate control circuit and complex control chip, without control power supply, and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a circuit principle diagram of the present invention;

[0030] Figure 2 This is a charging state circuit diagram of the present invention;

[0031] Figure 3 This is a reset state circuit diagram of the present invention. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar numbers throughout represent elements with the same or similar functions. However, it should be understood that the drawings are only used for illustrative purposes and are not to be construed as limiting the present invention. In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and are not to be construed as limiting the present invention.

[0033] The present invention will be further described below with reference to the accompanying drawings and examples, but they are not intended to limit the present invention.

[0034] Referring to the accompanying drawings, the present invention provides a DC battery charging device comprising a power connection structure 1, a battery charging interface 2, and a single-phase three-winding transformer 3. The three windings of the single-phase three-winding transformer 3 are a first winding K1, a second winding K2, and a third winding K3. The same-name end of the first winding K1 is connected to the positive electrode of the power connection structure 1, the negative electrode of the power connection structure 1 and the same-name end of the second winding K2 are both grounded, and the opposite-name end of the third winding K3 is connected to the negative electrode of the battery charging interface 2.

[0035] A full-controlled power switch G1 is provided between the opposite-name end of the K1 winding and the ground, the positive electrode of the full-controlled power switch G1 is connected to the opposite-name end of the first winding K1, and the negative electrode of the full-controlled power switch G1 is grounded. A first resistor R1, a sixth resistor R6, and a second capacitor C2 are sequentially connected in series between the power connection structure 1 and the second winding K2, the negative electrode of the second capacitor C2 is connected to the opposite-name end of the K2 winding, the control end of the full-controlled power switch G1 is connected between the first resistor R1 and the sixth resistor R6, and the potential point of the control end of the full-controlled power switch G1 is set to the first potential point. At point d1, when the power connection structure 1 with a voltage of U0 is connected to the circuit and generates current, a small current loop is formed through the first resistor R1, the sixth resistor R6, the second capacitor C2, and the second winding K2 in sequence, thereby raising the potential of the first potential point d1 until it reaches the trigger value of the full-controlled power switch G1, thereby turning on the full-controlled power switch G1. At this time, the current of the power connection structure 1 passes through the first winding K1 and the full-controlled power switch G1 to form a power-on loop, thereby charging the first winding K1, and at the same time, the third winding K3 generates an induced current.

[0036] The opposite-name end of the second winding K2 is connected to the cathode of the second diode D2, the same-name end of the second winding K2 is connected to the anode of the first capacitor C1, the cathode of the first capacitor C1 is connected to the anode of the second diode D2, the cathode of the first capacitor C1 is connected in series with the fifth resistor R5, the fourth resistor R4 and the second voltage-stabilizing diode Z2, the cathode of the second voltage-stabilizing diode Z2 is grounded, the cathode of the first capacitor C1 is also connected to the emitter of the transistor G3, and the base of the transistor G3 is connected between the fifth resistor R5 and the fourth resistor R4. The collector of the transistor G3 is connected in series with a third resistor R3 and a second resistor R2. One end of the second resistor R2 is connected between the first resistor R1 and the sixth resistor R6. The control end of the full-controlled power switch G1 is connected to the source of the PMOS transistor G2. The drain of the PMOS transistor G2 is grounded. The gate of the PMOS transistor G2 is connected between the third resistor R3 and the second resistor R2. The potential point of the gate of the PMOS transistor G2 is set as the second potential point d2. The potential point of the negative electrode of the first capacitor C1 is set as the third potential point d2. Assuming that the potential point of the base of the transistor G3 is the fourth potential point d4, the current in the second winding K2 sequentially passes through the first capacitor C1 and the second diode D2 to form a loop, thereby charging the first capacitor C1. At this time, the potential of the positive electrode of the first capacitor C1 and the potential of the same-name end of the second winding K2 are both ground potential. According to the current flow direction, the third potential point d3 will generate a negative potential. Since the potential of the negative electrode of the second voltage-stabilizing tube Z2 is the ground potential, when the potential of the third potential point d3 is lower than -30V, the second voltage-stabilizing tube Z2 The voltage regulator Z2 is turned on, and the current passes through the second voltage regulator Z2, the fourth resistor R4, the fifth resistor R5, and the third potential point d3 in sequence. At this time, the potential of the fourth potential point d4 is higher than that of the third potential point d3, and the transistor G3 is turned on. At this time, the potential of the second potential point d2 is lower than that of the first potential point d1, and the PMOS transistor G2 is turned on. The potential of the first potential point d1 is pulled to the ground potential, thereby turning off the full-controlled power switch G1, and the power connection structure 1 stops charging the first winding K1.

[0037] A third diode D3 is connected in series between the same-name end of the third winding K3 and the battery charging interface 2. The positive electrode of the third diode D3 is connected to the same-name end of the third winding K3, and the negative electrode of the third diode D3 is connected to the positive electrode of the battery charging interface 2. A fourth capacitor C4 is connected in parallel between the positive and negative ends of the battery charging interface 2, and the positive electrode of the fourth capacitor C4 is connected to the positive electrode of the battery charging interface 2. When the power connection structure 1 charges the first winding K1, an induced current is generated in the third winding K3, and the induced current charges the battery charging interface 2 through the third diode D3.

[0038] A first diode D1 and a seventh resistor R7 are sequentially connected in series between the opposite-name end and the same-name end of the first winding K1. A third capacitor C3 is connected in parallel across the second ends of the seventh resistor R7. The anode of the first diode D1 is connected to the opposite-name end of the first winding K1, the cathode of the first diode D1 is connected to the positive electrode of the third capacitor C3, and the negative electrode of the third capacitor C3 is connected to the positive electrode of the power connection structure 1. When the fully-controlled power switch G1 is turned off, the power connection structure 1 stops discharging, and the residual current in the first winding K1 flows sequentially through the parallel circuit of the first diode D1, the seventh resistor R7, and the third capacitor C3 until the current in the first winding K1 drops to zero.

[0039] A first voltage-stabilizing tube Z1 is connected in series between the gate of the PMOS tube G2 and the positive electrode of the second capacitor C2. The positive electrode of the first voltage-stabilizing tube Z1 is connected to the gate of the PMOS tube G2. Assuming that the potential point of the positive electrode of the second capacitor C2 is the fifth potential point d5, when the current in the second winding K2 decays as the current in the first winding K1 decays, the current in the second capacitor C2 flows to the ground through the second winding K2. At this time, the potential of the fifth potential point d5 is higher than the ground potential. When the potential difference between the fifth potential point d5 and the second potential point d2 exceeds the potential of the first voltage-stabilizing tube Z1, the voltage of the first voltage-stabilizing tube Z1 is 0. When the breakdown voltage of Z1 reaches the breakdown voltage of the transistor Z1, the first voltage-stabilizing diode Z1 breaks down in reverse, the current of the second capacitor C2 charging the first capacitor C1 through the third resistor R3 and the transistor G3 increases rapidly, the potential of the third potential point d3 increases rapidly, and the potential of the fourth potential point d4 also increases accordingly, the second voltage-stabilizing diode Z2 returns to the off state, the transistor G3 is then turned off, the potential of the second potential point d2 increases, the PMOS transistor G2 is turned off, and after the PMOS transistor G2 is turned off, the potential of the first potential point d1 increases, the full-controlled power switch G1 is turned on again, and the next charging cycle begins.

[0040] The trigger value of the full-control power switch G1 is 23V to 25V.

[0041] The breakdown voltages of the voltage regulator tubes Z1 and Z2 are the same, ranging from 30V to 35V.

[0042] Assume that the voltage connected to the power connection structure 1 is U0, and the winding ratio of the three-winding transformer is k1 / k2=U0 / 24; K3 / K1=10-30.

[0043] The capacitance ratio of the capacitor C2 to the capacitor C1 is 2:1.

[0044] Assume that the voltage connected to the power connection structure 1 is U0, and the voltage U0 ranges from 110V to 400V.

[0045] The present invention also provides a method for charging a DC battery, including the following working states and workflow:

[0046] When the power connection structure 1 is not connected to the circuit, the full-controlled power switch G1, PMOS transistor G2, and transistor G3 are all in the off state in the initial state;

[0047] When the power connection structure 1 with a voltage of U0 is connected to the circuit and generates current, a small current loop is formed through the first resistor R1, the sixth resistor R6, the second capacitor C2, and the second winding K2, thereby raising the potential of the first potential point d1 until it reaches the trigger value of the full-controlled power switch G1, thereby turning on the full-controlled power switch G1. At this time, the current forms a power-on loop through the first winding K1 and the full-controlled power switch G1, thereby charging the first winding K1. At the same time, the third winding K3 generates an induced current, which passes through the third diode D3 and charges the DC battery through the battery charging interface 2.

[0048] At this time, the current in the second winding K2 sequentially passes through the first capacitor C1 and the second diode D2 to form a loop, thereby charging the first capacitor C1. At this time, the potential of the positive electrode of the first capacitor C1 and the potential of the same-name end of the second winding K2 are both ground potential. According to the current flow direction, the third potential point d3 will generate a negative potential. Since the potential of the negative electrode of the second voltage-stabilizing diode Z2 is ground potential, when the potential of the third potential point d3 is lower than the conduction value of the second voltage-stabilizing diode Z2, the second voltage-stabilizing diode Z2 is turned on. The current sequentially passes through the second voltage-stabilizing diode Z2, the fourth resistor R4, the fifth resistor R5, and the third potential point d3. At this time, the potential of the fourth potential point d4 is higher than the third potential point d3, causing the transistor G3 to turn on, and the potential of the second potential point d2 to decrease. At this time, the potential of the second potential point d2 is lower than the potential of the first potential point d1, causing the PMOS transistor G2 to turn on. The potential of the first potential point d1, thereby turning off the fully-controlled power switch G1, stops charging the first winding K1;

[0049] When the fully controlled power switch G1 is turned off, the power connection structure 1 disconnects the circuit, and the residual current in the first winding K1 passes through the first diode D1, the seventh resistor R7, and the third capacitor C3 in sequence until the current in the first winding K1 drops to zero;

[0050] The current in the second winding K2 decays as the current in the first winding K1 decays. At this time, the current in the second winding K2 is generated by the charge in the second capacitor C2 flowing through the second winding K2 to the ground. This process causes the potential of the fifth potential point d5 to increase. When the potential difference between the fifth potential point d5 and the second potential point d2 exceeds the breakdown voltage of the first voltage-stabilizing diode Z1, the first voltage-stabilizing diode Z1 breaks down in reverse. The current of the second capacitor C2 charging the first capacitor C1 through the third resistor R3 and the transistor G3 increases rapidly. The potential of the third potential point d3 increases rapidly, and the potential of the fourth potential point d4 also increases accordingly. The second voltage-stabilizing diode Z2 returns to the off state, and the transistor G3 is subsequently turned off. The potential of the second potential point d2 increases, and the PMOS transistor G2 is turned off.

[0051] After the PMOS tube G2 is turned off, the potential of the first potential point d1 increases, and the full-control power switch G1 is turned on again, entering the next charging cycle.

[0052] The power connection structure 1 includes a circuit structure including a socket for connecting to the mains power, and also includes a connection structure for connecting to a rechargeable battery pack. In this embodiment, the power connection structure 1 is a connection structure for connecting to a rechargeable battery pack.

[0053] According to the description and drawings of the present invention, those skilled in the art can easily manufacture or use a DC battery charging device of the present invention, and can produce the positive effects described in the present invention.

[0054] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two mechanisms, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0055] In the description of the present invention, it should be understood that the terms "one end," "the other end," "outer side," "inner side," "horizontal," "end," "length," "outer end," "left," "right," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They do not indicate or imply that the mechanisms or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. The terms "first" and "second" are used solely for brevity of description and do not indicate or imply relative importance.

[0056] Furthermore, in practicing the claimed invention, variations to the disclosed embodiments may be understood and effected by those skilled in the art through a study of the drawings, the disclosure, and the appended claims. Furthermore, in the claims and the specification, words such as "comprise," "comprising," and the like do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the present invention are covered by the scope of the claims of the present invention and will not be listed one by one here.

Claims

1. A DC battery charging device, characterized in that: The invention comprises a power connection structure (1), a battery charging interface (2) and a single-phase three-winding transformer (3), wherein the three windings of the single-phase three-winding transformer (3) are respectively a first winding (K1), a second winding (K2) and a third winding (K3), the same-name end of the first winding (K1) is connected to the positive pole of the power connection structure (1), the negative pole of the power connection structure (1) and the same-name end of the second winding (K2) are both grounded, and the opposite-name end of the third winding (K3) is connected to the negative pole of the battery charging interface (2); A full-controlled power switch (G1) is provided between the opposite-name end of the (K1) winding and the ground, the positive electrode of the full-controlled power switch (G1) is connected to the opposite-name end of the first winding (K1), and the negative electrode of the full-controlled power switch (G1) is grounded; a first resistor (R1), a sixth resistor (R6) and a second capacitor (C2) are sequentially connected in series between the power connection structure (1) and the second winding (K2); the negative electrode of the second capacitor (C2) is connected to the opposite-name end of the (K2) winding; the control end of the full-controlled power switch (G1) is connected between the first resistor (R1) and the sixth resistor (R6); and the potential point of the control end of the full-controlled power switch (G1) is set as the first potential point (d1); The opposite-name end of the second winding (K2) is connected to the negative electrode of the second diode (D2), the same-name end of the second winding (K2) is connected to the positive electrode of the first capacitor (C1), the negative electrode of the first capacitor (C1) is connected to the positive electrode of the second diode (D2), the negative electrode of the first capacitor (C1) is connected in series with a fifth resistor (R5), a fourth resistor (R4) and a second voltage-stabilizing diode (Z2), the negative electrode of the second voltage-stabilizing diode (Z2) is grounded, the negative electrode of the first capacitor (C1) is also connected to the emitter of a transistor (G3), the base of the transistor (G3) is connected between the fifth resistor (R5) and the fourth resistor (R4), and the collector of the transistor (G3) is connected in series with the fifth resistor (R5), the fourth resistor (R4) and the second voltage-stabilizing diode (Z2). A third resistor (R3) and a second resistor (R2) are connected in series, one end of the second resistor (R2) is connected between the first resistor (R1) and the sixth resistor (R6), the control end of the fully controlled power switch (G1) is connected to the source of the PMOS tube (G2), the drain of the PMOS tube (G2) is grounded, the gate of the PMOS tube (G2) is connected between the third resistor (R3) and the second resistor (R2), the potential point of the gate of the PMOS tube (G2) is set as the second potential point (d2), the potential point of the negative electrode of the first capacitor (C1) is set as the third potential point (d3), and the potential point of the base of the transistor (G3) is set as the fourth potential point (d4); A third diode (D3) is connected in series between the same-name end of the third winding (K3) and the battery charging interface (2); the positive electrode of the third diode (D3) is connected to the same-name end of the third winding (K3); the negative electrode of the third diode (D3) is connected to the positive electrode of the battery charging interface (2); a fourth capacitor (C4) is connected in parallel between the positive and negative electrodes of the battery charging interface (2); the positive electrode of the fourth capacitor (C4) is connected to the positive electrode of the battery charging interface (2).

2. A DC battery charging device according to claim 1, characterized in that: A first diode (D1) and a seventh resistor (R7) are sequentially connected in series between the opposite-name end and the same-name end of the first winding (K1); a third capacitor (C3) is connected in parallel between the two ends of the seventh resistor (R7); the positive electrode of the first diode (D1) is connected to the opposite-name end of the first winding (K1); the negative electrode of the first diode (D1) is connected to the positive electrode of the third capacitor (C3); and the negative electrode of the third capacitor (C3) is connected to the positive electrode of the power connection structure (1); A first voltage-stabilizing tube (Z1) is connected in series between the gate of the PMOS tube (G2) and the positive electrode of the second capacitor (C2); the positive electrode of the first voltage-stabilizing tube (Z1) is connected to the gate of the PMOS tube (G2); and the potential point of the positive electrode of the second capacitor (C2) is set as a fifth potential point (d5).

3. A DC battery charging device according to claim 1, characterized in that: The trigger value of the full-control power switch (G1) is 23V to 25V.

4. A DC battery charging device according to claim 2, characterized in that: The breakdown voltages of the voltage regulator tubes (Z1) and (Z2) are the same and range from 30 to 35V.

5. A DC battery charging device according to claim 1, characterized in that: Assuming that the voltage connected to the power connection structure (1) is U0, the winding ratio of the three-winding transformer is k1 / k2=U0 / 24; k3 / k1=10-30.

6. A DC battery charging device according to claim 1, characterized in that: The capacitance ratio of the capacitor (C2) to the capacitor (C1) is 2:

1.

7. A DC battery charging device according to claim 1, characterized in that: Assuming that the voltage connected to the power connection structure (1) is U0, the voltage range of the power connection structure U0 is 110V to 400V.

8. A DC battery charging method, characterized in that: When the power connection structure (1) is not connected to the circuit, the fully controlled power switch (G1), the PMOS tube (G2), and the triode (G3) are all in the off state in the initial state; When the power connection structure (1) with a voltage of U0 is connected to the circuit and generates current, a small current loop is formed through the first resistor (R1), the sixth resistor (R6), the second capacitor (C2) and the second winding (K2), thereby raising the potential of the first potential point (d1) until it reaches the trigger value of the full-controlled power switch (G1), thereby turning on the full-controlled power switch (G1). At this time, the current passes through the first winding (K1) and the full-controlled power switch (G1) to form a power-on loop, thereby charging the first winding (K1). At the same time, the third winding (K3) generates an induced current, which passes through the third diode (D3) and the battery charging interface (2) to charge the DC battery; At this time, the current in the second winding (K2) sequentially passes through the first capacitor (C1) and the second diode (D2) to form a loop, thereby charging the first capacitor (C1). At this time, the potential of the positive electrode of the first capacitor (C1) and the potential of the same-name end of the second winding (K2) are both ground potential. According to the direction of current flow, the third potential point (d3) will generate a negative potential. Since the potential of the negative electrode of the second voltage-stabilizing tube (Z2) is the ground potential, when the potential of the third potential point (d3) is lower than the conduction value of the second voltage-stabilizing tube (Z2), the second voltage-stabilizing tube (Z2) is turned on, and the current sequentially passes through the second voltage-stabilizing tube (Z2). tube (Z2), a fourth resistor (R4), a fifth resistor (R5), and a third potential point (d3). At this time, the potential of the fourth potential point (d4) is higher than that of the third potential point (d3), causing the triode (G3) to be turned on, and the potential of the second potential point (d2) to decrease. At this time, the potential of the second potential point (d2) is lower than that of the first potential point (d1), causing the PMOS tube (G2) to be turned on, and the potential of the first potential point (d1) to be pulled to the ground potential, thereby turning off the full-controlled power switch (G1), and the power supply connection structure (1) stops charging the first winding (K1); When the fully controlled power switch (G1) is turned off, the power connection structure (1) disconnects the circuit, and the residual current in the first winding (K1) passes through the first diode (D1), the seventh resistor (R7), and the third capacitor (C3) in sequence until the current in the first winding (K1) drops to zero; The current in the second winding (K2) decays as the current in the first winding (K1) decays. At this time, the current in the second winding (K2) is generated by the charge in the second capacitor (C2) flowing through the second winding (K2) to the ground. This process causes the potential of the fifth potential point (d5) to increase. When the potential difference between the fifth potential point (d5) and the second potential point (d2) exceeds the breakdown voltage of the first voltage-stabilizing tube (Z1), the first voltage-stabilizing tube (Z1) reversely breaks down. The current of the second capacitor (C2) charging the first capacitor (C1) through the third resistor (R3) and the transistor (G3) increases rapidly. The potential of the third potential point (d3) increases rapidly, and the potential of the fourth potential point (d4) also increases accordingly. The second voltage-stabilizing tube (Z2) returns to the off state, the transistor (G3) is then turned off, the potential of the second potential point (d2) increases, and the PMOS tube (G2) is turned off. After the PMOS tube (G2) is turned off, the potential of the first potential point (d1) increases, and the full-controlled power switch (G1) is turned on again, entering the next charging cycle.

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