Charging control circuit, charging control method and charging controller

Abstract

The invention relates to a charging control circuit, a charging control method and a charging controller. Comprising a main control unit, a first H-bridge power unit, a second H-bridge power unit, a photovoltaic access unit, a generator access unit, a battery access unit, a switch assembly, a pre-charging and pre-discharging unit and a switch tube. A photovoltaic input switch and a photovoltaic pre-charging switch of the photovoltaic access unit are arranged between a photovoltaic interface and a photovoltaic input capacitor; a generator input switch and a generator pre-charging switch of the generator access unit are arranged between a generator interface and a generator input capacitor; a battery input switch and a battery pre-charging switch of the battery access unit are arranged between a battery interface and a battery input capacitor; the photovoltaic input capacitor, the generator input capacitor and the battery input capacitor are connected with the first end of the switch tube through the pre-charging and pre-discharging unit, and the second end of the switch tube is grounded; and the main control unit is used for controlling the working states of the switches, the pre-charging and pre-discharging unit and the switching tubes. The circuit reliability can be improved, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging control, in particular to a charging control circuit and method thereof, and a charging controller. BACKGROUND

[0002] The photovoltaic and generator two-in-one charging controller is widely used in off-grid power supply systems, emergency power supplies or remote power supply and the like.

[0003] The charging control circuit of the charging controller usually comprises a photovoltaic interface, a photovoltaic input switch, a photovoltaic input capacitor, a generator interface, a generator input switch, a generator input capacitor, a double H-bridge power circuit, a battery interface, a battery input switch and a battery input capacitor, and the double H-bridge is connected by a switch component in the middle to realize the bidirectional flow of energy. However, when the photovoltaic input capacitor voltage is much greater than the generator input capacitor voltage and the middle switch is closed at the moment, the photovoltaic input capacitor charges the generator input capacitor quickly, which generates a huge inrush current that can easily damage the switch device, even if high-performance devices are used, there are still safety hazards, and the cost is relatively high; repeated surge impact leads to shortened device life and reduced system reliability; when the middle switch device is damaged, the photovoltaic interface and the generator interface form a short-circuit loop at this time, which has a great safety hazard.

[0004] Therefore, it is necessary to design a charging control circuit with lower cost, higher reliability and reduced safety hazards. SUMMARY

[0005] The present application provides a charging control circuit and method thereof, and a charging controller to solve the problems of high cost, low reliability and great safety hazards of the charging control circuit.

[0006] The present application discloses a charging control circuit, comprising a main control unit, a first H-bridge power unit, a second H-bridge power unit, a photovoltaic access unit, a generator access unit, a battery access unit, a switch component, a pre-charge and discharge unit and a switch tube. The photovoltaic access unit comprises a photovoltaic interface, a photovoltaic input capacitor, a photovoltaic input switch and a photovoltaic pre-charge switch, the photovoltaic input capacitor is connected in parallel to the voltage input end of the first H-bridge power unit, and the photovoltaic input switch and the photovoltaic pre-charge switch are both arranged between the photovoltaic interface and the photovoltaic input capacitor. The generator access unit comprises a generator interface, a generator input capacitor, a generator input switch and a generator pre-charge switch, the generator input capacitor is connected in parallel to the voltage input end of the second H-bridge power unit, and the generator input switch and the generator pre-charge switch are both arranged between the generator interface and the generator input capacitor. The battery access unit comprises a battery interface, a battery input capacitor, a battery input switch and a battery pre-charging switch, the battery input capacitor is connected in parallel to voltage output ends of the first H-bridge power unit and the second H-bridge power unit, and the battery input switch and the battery pre-charging switch are both arranged between the battery interface and the battery input capacitor; The photovoltaic input capacitor, the generator input capacitor and the battery input capacitor are connected to the first end of the switch tube through the pre-charging and discharging unit, and the second end of the switch tube is grounded. The switch assembly is arranged between the voltage input end of the first H-bridge power unit and the voltage input end of the second H-bridge power unit. The main control unit is used for controlling working states of the photovoltaic input switch, the photovoltaic pre-charging switch, the battery pre-charging switch, the battery input switch, the generator input switch, the generator pre-charging switch, the pre-charging and discharging unit and the switch tube, so as to charge the battery connected to the battery interface.

[0007] Optionally, the pre-charging and discharging unit comprises a first pre-discharging branch, a second pre-discharging branch and a third pre-discharging branch, the photovoltaic input capacitor is connected to the first end of the switch tube through the first pre-discharging branch, the generator input capacitor is connected to the first end of the switch tube through the second pre-discharging branch, and the battery input capacitor is connected to the first end of the switch tube through the third pre-discharging branch.

[0008] Optionally, the first pre-discharging branch comprises a first resistor and a first diode, the first resistor is connected in series between the photovoltaic pre-charging switch and the positive electrode of the photovoltaic input capacitor, the positive electrode of the first diode is connected to the first resistor, and the negative electrode of the first diode is connected to the first end of the switch tube.

[0009] Optionally, the second pre-discharging branch comprises a second resistor and a second diode, the second resistor is connected in series between the generator pre-charging switch and the positive electrode of the generator input capacitor, the positive electrode of the second diode is connected to the second resistor, and the negative electrode of the second diode is connected to the first end of the switch tube.

[0010] Optionally, the third pre-discharging branch comprises a third resistor and a third diode, the third resistor is connected in series between the battery pre-charging switch and the positive electrode of the battery input capacitor, the positive electrode of the third diode is connected to the third resistor, and the negative electrode of the third diode is connected to the first end of the switch tube.

[0011] Optionally, the photovoltaic input switch, the photovoltaic pre-charge switch, the battery pre-charge switch, the battery input switch and the generator input switch are all relays, the master control unit comprises a master control chip and a Darlington transistor array, the master control chip is connected to the control end of the switch tube, the first H-bridge power unit, the second H-bridge power unit and the switch assembly, and the signal input end of the Darlington transistor array is connected to the master control chip, and the power output end of the Darlington transistor array is connected to the control end of each relay.

[0012] Optionally, the charging control circuit further comprises a drive protection unit connected to the switch tube, the drive protection unit comprises a fourth resistor, a fifth resistor and a bleeder capacitor, the fourth resistor is connected in series between the master control chip and the control end of the switch tube, and the fifth resistor and the bleeder capacitor are connected in parallel and arranged between the control end and the second end of the switch tube.

[0013] Optionally, the switch assembly comprises a first NMOS tube and a second NMOS tube, the source of the first NMOS tube is connected to the source of the second NMOS tube, the drain of the first NMOS tube is connected to the voltage input end of the first H-bridge power unit, the drain of the second NMOS tube is connected to the voltage input end of the second H-bridge power unit, and the gate of the first NMOS tube and the gate of the second NMOS tube are both connected to the master control unit.

[0014] The application further discloses a charging controller comprising a shell, a circuit board and the charging control circuit according to any one of the preceding charging control circuits, wherein the charging control circuit is arranged on the circuit board, and the circuit board is arranged in the shell.

[0015] The application further discloses a charging control method applied to the charging control circuit according to any one of the preceding charging control circuits, and the charging control method comprises the following steps. controlling the switch tube to be turned on, discharging the photovoltaic input capacitor, the generator input capacitor and the battery input capacitor through the pre-charge and discharge unit, and turning off the switch tube after the discharging is completed; controlling the battery pre-charge switch to be turned on, pre-charging the battery input capacitor, and turning on the battery input switch after the pre-charging is completed; controlling the on-off state of the switch assembly according to a preset charging mode, wherein the preset charging mode comprises a photovoltaic charging mode only, a generator charging mode only and a hybrid charging mode; controlling the on-off state of the photovoltaic pre-charge switch and the generator pre-charge switch according to the preset charging mode, so as to charge the photovoltaic input capacitor and / or the generator input capacitor, and turning on the photovoltaic input switch or the generator input switch correspondingly after the charging is completed; The first H-bridge power unit and the second H-bridge power unit are controlled to operate in order to charge the battery connected to the battery interface.

[0016] The beneficial effects of the charging control circuit provided in this embodiment of the invention are as follows: By configuring a pre-charge and discharge unit, the photovoltaic input capacitor, generator input capacitor, and battery input capacitor can be grounded through a common switch tube of the pre-charge and discharge unit to achieve pre-discharge, simplifying the circuit structure while effectively releasing the residual voltage of each input capacitor and improving circuit safety; furthermore, before the battery is officially charged, the photovoltaic input capacitor, generator input capacitor, and battery input capacitor can be pre-charged by turning on the corresponding pre-charge switch. Since the photovoltaic input capacitor, generator input capacitor, and battery input capacitor can be pre-discharged and pre-charged, the possibility of surge current generation is reduced when the photovoltaic input switch, generator input switch, and switch assembly are turned on, improving circuit reliability and reducing safety hazards; because the surge current is effectively suppressed, the tolerance performance requirements of the photovoltaic input switch, generator input switch, and switch assembly are reduced, and lower-cost general-purpose devices can be used to replace high-performance special-purpose devices, resulting in lower overall cost. Attached Figure Description

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a circuit diagram of the charging control circuit according to an embodiment of the present invention; Figure 2 This is a partial circuit diagram showing the connection between the pre-charge / discharge unit and the switching transistor in an embodiment of the present invention; Figure 3 This is a circuit diagram of a Darlington transistor array according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the current flow direction of the charging control circuit according to an embodiment of the present invention; Figure 5 This is a flowchart illustrating the charging control method according to an embodiment of the present invention.

[0018] The labels for the attached figures are as follows: 10. Main control unit; 20. First H-bridge power unit; 30. Second H-bridge power unit; 40. Photovoltaic access unit; 41. Photovoltaic interface; 50. Generator access unit; 51. Generator interface; 60. Battery access unit; 61. Battery interface; 70. Switch assembly; 80. Pre-charge / discharge unit; Q1, Switching transistor; Q2, First NMOS transistor; Q3, Second NMOS transistor; Q4, Third NMOS transistor; Q5, Fourth NMOS transistor; Q6, Fifth NMOS transistor; Q7, Sixth NMOS transistor; Q8, Seventh NMOS transistor; Q9, Eighth NMOS transistor; Q10, Ninth NMOS transistor; Q11, Tenth NMOS transistor; C1, Photovoltaic input capacitor; C2, Generator input capacitor; C3, Battery input capacitor; C4, Leakage capacitor; K1, Photovoltaic input switch; K2, Photovoltaic precharge switch; K3, Generator input switch; K4, Generator precharge switch; K5, Battery input switch; K6, Battery precharge switch; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; R5, Fifth resistor; D1, First diode; D2, Second diode; D3, Third diode; U1, Darlington transistor array; L1, First inductor; L2, Second inductor. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] This invention provides a charging control circuit, such as... Figures 1 to 3As shown, the charging control circuit includes a main control unit 10, a first H-bridge power unit 20, a second H-bridge power unit 30, a photovoltaic access unit 40, a generator access unit 50, a battery access unit 60, a switching assembly 70, a pre-charge / discharge unit 80, and a switching transistor Q1. The photovoltaic access unit 40 includes a photovoltaic interface 41, a photovoltaic input capacitor C1, a photovoltaic input switch K1, and a photovoltaic pre-charge switch K2. The photovoltaic input capacitor C1 is connected in parallel to the voltage input terminal of the first H-bridge power unit 20. The photovoltaic input switch K1 and the photovoltaic pre-charge switch K2 are both located between the photovoltaic interface 41 and the photovoltaic input capacitor C1. The generator access unit 50 includes a generator interface 51, a generator input capacitor C2, a generator input switch K3, and a generator pre-charge switch K4. The generator input capacitor C2 is connected in parallel to the voltage input terminal of the second H-bridge power unit 30. The generator input switch K3 and the generator pre-charge switch K4 are both located between the generator interface 51 and the generator input capacitor C2. The battery access unit... Unit 60 includes a battery interface 61, a battery input capacitor C3, a battery input switch K5, and a battery precharge switch K6. The battery input capacitor C3 is connected in parallel to the voltage output terminals of the first H-bridge power unit 20 and the second H-bridge power unit 30. The battery input switch K5 and the battery precharge switch K6 are both located between the battery interface 61 and the battery input capacitor C3. The photovoltaic input capacitor C1, the generator input capacitor C2, and the battery input capacitor C3 are connected to the first terminal of the switch transistor Q1 through the precharge and discharge unit 80, and the second terminal of the switch transistor Q1 is grounded. The switch assembly 70 is located between the voltage input terminals of the first H-bridge power unit 20 and the second H-bridge power unit 30. The main control unit 10 is used to control the working state of the photovoltaic input switch K1, the photovoltaic precharge switch K2, the battery precharge switch K6, the battery input switch K5, the generator input switch K3, the generator precharge switch K4, the precharge and discharge unit 80, and the switch transistor Q1 to realize the charging of the battery connected to the battery interface 61.

[0021] The charging control circuit of this embodiment configures a pre-charge / discharge unit 80. The photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 can be grounded through a common switch Q1 of the pre-charge / discharge unit 80, achieving pre-discharge. This simplifies the circuit structure and effectively releases the residual voltage of each input capacitor, improving circuit safety. Furthermore, before the battery is officially charged, the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 can be pre-charged by turning on their respective pre-charge switches. Since the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 can be pre-discharged and pre-charged, the possibility of surge current generation is reduced when the photovoltaic input switch K1, generator input switch K3, and switch assembly 70 are turned on, improving circuit reliability and reducing safety hazards. Because the surge current is effectively suppressed, the tolerance requirements of the photovoltaic input switch K1, generator input switch K3, and switch assembly 70 are reduced, and lower-cost general-purpose devices can be used instead of high-performance dedicated devices, resulting in lower overall costs.

[0022] Optionally, the switching transistor Q1 can be implemented using a transistor or an NMOS transistor. Preferably, the switching transistor Q1 is a transistor, which has a lower drive threshold, lower cost, stronger anti-static and surge protection, and higher reliability.

[0023] In an optional embodiment of this application, the pre-charge and discharge unit 80 includes a first pre-discharge branch, a second pre-discharge branch, and a third pre-discharge branch. The photovoltaic input capacitor C1 is connected to the first terminal of the switching transistor Q1 through the first pre-discharge branch; the generator input capacitor C2 is connected to the first terminal of the switching transistor Q1 through the second pre-discharge branch; and the battery input capacitor C3 is connected to the first terminal of the switching transistor Q1 through the third pre-discharge branch.

[0024] Specifically, by setting up a first pre-discharge branch, a second pre-discharge branch, and a third pre-discharge branch, corresponding to the photovoltaic input capacitor C1, the generator input capacitor C2, and the battery input capacitor C3 respectively, they are independent of each other. When one of the pre-discharge branches fails, it only affects the discharge of the corresponding capacitor and does not affect the normal pre-discharge operation of the other two capacitors, which is also conducive to the rapid troubleshooting of faults.

[0025] like Figure 1 and Figure 2 As shown, in an optional embodiment of this application, the first pre-charge branch includes a first resistor R1 and a first diode D1. The first resistor R1 is connected in series between the photovoltaic pre-charge switch K2 and the positive terminal of the photovoltaic input capacitor C1. The positive terminal of the first diode D1 is connected to the first resistor R1, and its negative terminal is connected to the first terminal of the switching transistor Q1.

[0026] Specifically, the first resistor R1 is connected in series between the photovoltaic pre-charge switch K2 and the positive terminal of the photovoltaic input capacitor C1, and its core function is current limiting. During the pre-discharge phase, the first resistor R1 limits the discharge current from the photovoltaic input capacitor C1 to the switching transistor Q1, preventing the photovoltaic input capacitor C1 from overheating and being damaged due to instantaneous high-current discharge. Simultaneously, during the pre-charging phase of the photovoltaic input capacitor C1, the first resistor R1 assists the photovoltaic pre-charge switch K2 in achieving soft charging, further suppressing pre-charging surge current. The first diode D1 serves as unidirectional conduction and reverse isolation. By setting the first diode D1, only the residual energy of the photovoltaic input capacitor C1 is allowed to flow to ground through the loop formed by the first resistor R1, the first diode D1, and the switching transistor Q1, completing the discharge. At the same time, it blocks the backflow of current from other pre-discharge branches to the photovoltaic side, avoiding interference with the voltage stability of the photovoltaic input capacitor C1 and preventing energy backflow from causing device malfunction.

[0027] like Figure 1 and Figure 2 As shown, in an optional embodiment of this application, the second pre-charge branch includes a second resistor R2 and a second diode D2. The second resistor R2 is connected in series between the generator pre-charge switch K4 and the positive terminal of the generator input capacitor C2. The positive terminal of the second diode D2 is connected to the second resistor R2, and its negative terminal is connected to the first terminal of the switch transistor Q1.

[0028] Specifically, the second resistor R2 is connected in series between the generator pre-charge switch K4 and the positive terminal of the generator input capacitor C2, and its core function is current limiting. During the pre-discharge phase, the second resistor R2 limits the discharge current flowing from the generator input capacitor C2 to the switching transistor Q1, preventing the generator input capacitor C2 from overheating and being damaged due to instantaneous large current discharge. Simultaneously, during the pre-charging phase of the generator input capacitor C2, the second resistor R2 assists the generator pre-charge switch K4 in achieving soft charging, further suppressing pre-charging surge current. The second diode D2 serves as unidirectional conduction and reverse isolation. By setting the second diode D2, only the residual energy of the generator input capacitor C2 is allowed to flow to ground through the loop formed by the second resistor R2, the second diode D2, and the switching transistor Q1, completing the discharge. At the same time, it blocks the backflow of current from other pre-discharge branches to the generator side, avoiding interference with the voltage stability of the generator input capacitor C2 and preventing energy backflow from causing device malfunction.

[0029] like Figure 1 and Figure 2 As shown, in an optional embodiment of this application, the third pre-charge branch includes a third resistor R3 and a third diode D3. The third resistor R3 is connected in series between the battery pre-charge switch K6 and the positive terminal of the battery input capacitor C3. The positive terminal of the third diode D3 is connected to the third resistor R3, and its negative terminal is connected to the first terminal of the switch transistor Q1.

[0030] Specifically, the third resistor R3 is connected in series between the battery pre-charge switch K6 and the positive terminal of the battery input capacitor C3, and its core function is current limiting. During the pre-discharge phase, the third resistor R3 limits the discharge current from the battery input capacitor C3 to the switching transistor Q1, preventing the battery input capacitor C3 from overheating and being damaged due to instantaneous high-current discharge. Simultaneously, during the pre-charge phase of the battery input capacitor C3, the third resistor R3 assists the battery pre-charge switch K6 in achieving soft charging, further suppressing pre-charge surge current. The third diode D3 serves as unidirectional conduction and reverse isolation. By setting the third diode D3, only the residual energy of the battery input capacitor C3 is allowed to flow to ground through the loop formed by the third resistor R3, the third diode D3, and the switching transistor Q1, completing the discharge. At the same time, it blocks the backflow of current from other pre-discharge branches to the battery side, avoiding interference with the voltage stability of the battery input capacitor C3 and preventing energy backflow from causing device malfunction.

[0031] like Figures 1 to 3 As shown, in an optional embodiment of this application, the photovoltaic input switch K1, photovoltaic precharge switch K2, battery precharge switch K6, battery input switch K5, and generator input switch K3 are all relays. The main control unit 10 includes a main control chip and a Darlington transistor array U1. The main control chip is connected to the control terminals of the switching transistor Q1, the first H-bridge power unit 20, the second H-bridge power unit 30, and the switching assembly 70. The signal input terminal of the Darlington transistor array U1 is connected to the main control chip, and its power output terminal is connected to the control terminals of each relay.

[0032] Specifically, the photovoltaic input switch K1, photovoltaic precharge switch K2, battery precharge switch K6, battery input switch K5, and generator input switch K3 use relays as switches. The relay contacts can withstand high voltage and high current surges, directly carrying the power stage current from the photovoltaic, generator, and battery sides. They have strong carrying capacity and are easy to control. However, the relay control terminal requires a large drive current to engage, while the main control chip's output current is too weak to directly drive the relays. The Darlington transistor array U1, with its high current gain, amplifies the weak electrical signal output by the main control chip into a strong current sufficient to drive the relay coil, ensuring stable engagement and disengagement of all relays, including the photovoltaic input switch K1 and the precharge switch. The Darlington transistor array U1 integrates multiple drive channels, allowing a single chip to simultaneously drive all relays, including the photovoltaic input switch K1, photovoltaic precharge switch K2, battery precharge switch K6, battery input switch K5, and generator input switch K3. This replaces the distributed drive scheme of multiple discrete transistors, reducing the number of components and wiring complexity, and shrinking the circuit board size.

[0033] Alternatively, the Darlington transistor array U1 can be model ULN2003A, and its circuit diagram is shown below. Figure 3 As shown.

[0034] likeFigure 1 and Figure 2 As shown, in an optional embodiment of this application, the charging control circuit further includes a drive protection unit connected to the switching transistor Q1. The drive protection unit includes a fourth resistor R4, a fifth resistor R5, and a discharge capacitor C4. The fourth resistor R4 is connected in series between the main control chip and the control terminal of the switching transistor Q1. The fifth resistor R5 is connected in parallel with the discharge capacitor C4 and is arranged in parallel between the control terminal and the second terminal of the switching transistor Q1.

[0035] Specifically, the fourth resistor R4 limits the drive current output from the main control chip to the control terminal of the switching transistor Q1, preventing excessive current from burning out Q1. This matches the drive current requirements of Q1, enabling it to stably and quickly complete the turn-on and turn-off actions, preventing insufficient drive current from causing Q1 to enter the linear region and overheat and be damaged. The fifth resistor R5 is connected in parallel with the bleeder capacitor C4. When the switching state of Q1 changes, the junction capacitance stores charge, affecting the switching speed. Connecting an appropriate bleeder capacitor C4 and the fifth resistor R5 in parallel provides a transient current path, accelerating charge discharge and speeding up the switching process.

[0036] like Figure 1 As shown, in an optional embodiment of this application, the switching component 70 includes a first NMOS transistor Q2 and a second NMOS transistor Q3. The source of the first NMOS transistor Q2 is connected to the source of the second NMOS transistor Q3. The drain of the first NMOS transistor Q2 is connected to the voltage input terminal of the first H-bridge power unit 20. The drain of the second NMOS transistor Q3 is connected to the voltage input terminal of the second H-bridge power unit 30. The gates of the first NMOS transistor Q2 and the second NMOS transistor Q3 are both connected to the main control unit 10.

[0037] Specifically, when the main control unit 10 outputs a high-level drive gate, the first NMOS transistor Q2 and the second NMOS transistor Q3 are turned on, enabling bidirectional current flow at the voltage input terminals of the first H-bridge power unit 20 and the second H-bridge power unit 30. This adapts to the power convergence requirements when photovoltaic and generator power supply are coordinated, or both photovoltaic and generator power units can charge the battery through the first H-bridge power unit 20 and the second H-bridge power unit 30. When the gate input of the first NMOS transistor Q2 and the second NMOS transistor Q3 is low, they are turned off, achieving electrical isolation at the voltage input terminals of the first H-bridge power unit 20 and the second H-bridge power unit 30, preventing energy backflow. By controlling the on and off states of the first NMOS transistor Q2 and the second NMOS transistor Q3, automatic switching between photovoltaic and generator input sources can be achieved.

[0038] In other embodiments, the switch assembly 70 may also be a relay, a mechanical switch, or a similar switch.

[0039] In the embodiments of this application, such as Figure 1As shown, the first H-bridge power unit 20 includes a third NMOS transistor Q4, a fourth NMOS transistor Q5, a fifth NMOS transistor Q6, a sixth NMOS transistor Q7, and a first inductor L1. The source of the third NMOS transistor Q4 is connected to the drain of the fourth NMOS transistor Q5 and to one end of the first inductor L1. The drain of the third NMOS transistor Q4 serves as the voltage input terminal of the first H-bridge power unit 20 and is connected to the positive terminal of the photovoltaic input capacitor C1. The source of the fourth NMOS transistor Q5 is grounded. The source of the fifth NMOS transistor Q6 is connected to the drain of the sixth NMOS transistor Q7 and to the other end of the first inductor L1. The drain of the fifth NMOS transistor Q6 serves as the voltage output terminal of the first H-bridge power unit 20 and is connected to the positive terminal of the battery input capacitor C3. The source of the sixth NMOS transistor Q7 is grounded. The gates of the third NMOS transistor Q4, the fourth NMOS transistor Q5, the fifth NMOS transistor Q6, and the sixth NMOS transistor Q7 are all connected to the main control chip. The main control chip can charge the battery by controlling the conduction and disconnection of the third NMOS transistor Q4, the fourth NMOS transistor Q5, the fifth NMOS transistor Q6, and the sixth NMOS transistor Q7, in conjunction with the first inductor L1.

[0040] The second H-bridge power unit 30 includes a seventh NMOS transistor Q8, an eighth NMOS transistor Q9, a ninth NMOS transistor Q10, a tenth NMOS transistor Q11, and a second inductor L2. The source of the seventh NMOS transistor Q8 is connected to the drain of the eighth NMOS transistor Q9 and one end of the second inductor L2. The drain of the seventh NMOS transistor Q8 serves as the voltage input terminal of the second H-bridge power unit 30 and is connected to the positive terminal of the photovoltaic input capacitor C1. The source of the eighth NMOS transistor Q9 is grounded. The source of the ninth NMOS transistor Q10 is connected to the drain of the tenth NMOS transistor Q11 and the other end of the second inductor L2. The drain of the ninth NMOS transistor Q10 serves as the voltage output terminal of the second H-bridge power unit 30 and is connected to the positive terminal of the battery input capacitor C3. The source of the tenth NMOS transistor Q11 is grounded. The gates of the seventh NMOS transistor Q8, the eighth NMOS transistor Q9, the ninth NMOS transistor Q10, and the tenth NMOS transistor Q11 are all connected to the main control chip. The main control chip can charge the battery by controlling the conduction and disconnection of the seventh NMOS transistor Q8, the eighth NMOS transistor Q9, the ninth NMOS transistor Q10, and the tenth NMOS transistor Q11, in conjunction with the second inductor L2.

[0041] The charging control circuit of this application embodiment has multiple charging modes. The following describes in detail the operation of the charging control circuit in photovoltaic charging mode only, generator charging mode only, and hybrid charging mode with reference to the accompanying drawings.

[0042] like Figures 1 to 4As shown, in the photovoltaic-only charging mode, with photovoltaic interface 41 connected to the photovoltaic system and battery interface 61 connected to the battery, the first step is as follows: Before charging, the capacitor energy is discharged through the pre-charge / discharge unit. The main control chip enables the Dsicharge_EN pin, and the switch Q1 is turned on. The photovoltaic input capacitor C1 is discharged through circuit 7 via the first resistor R1 and the first diode D1; the generator input capacitor C2 is discharged through circuit 8 via the second resistor R2 and the second diode D2; and the battery input capacitor C3 is discharged through circuit 9 via the third resistor R3 and the third diode D3. After the voltages of the photovoltaic input capacitor C1, the generator input capacitor C2, and the battery input capacitor C3 are discharged to a consistent voltage, the main control chip disables the Dsicharge_EN pin. The second step is to pre-charge the battery input capacitor C3. The battery is pre-charged through circuit 3 via the battery pre-charge switch K6 and the third resistor R3. After pre-charging is completed, the battery input switch K5 is turned on. At this time, there is no surge current, and the opening is safe and reliable. Moreover, the battery input switch K5 can be a lower-cost device. Step 3: Turn on the first NMOS transistor Q2 and the second NMOS transistor Q3. Since the voltages of the photovoltaic input capacitor C1 and the generator input capacitor C2 are the same, there is no inrush current when turning on the first NMOS transistor Q2 and the second NMOS transistor Q3, ensuring safe and reliable startup. Furthermore, the first NMOS transistor Q2 and the second NMOS transistor Q3 can be lower-cost NMOS transistors. At this moment, the photovoltaic input capacitor C1 and the generator input capacitor C2 are essentially connected in parallel. Step 4: Turn on the photovoltaic pre-charge switch K2. The photovoltaic system charges both the photovoltaic input capacitor C1 and the generator input capacitor C2 simultaneously through circuit 1 and the first resistor R1. After charging is complete, turn on the photovoltaic input switch K1. There is no inrush current at this time, ensuring safe and reliable startup. Furthermore, the photovoltaic input switch K1 can be a lower-cost device. Step 5: Control the soft switching and soft-start waveform generation of the first H-bridge power unit 20 and the second H-bridge power unit 30, achieving current-free operation throughout the process. Furthermore, the NMOS transistors in the first H-bridge power unit 20 and the second H-bridge power unit 30 can be lower-cost NMOS transistors.

[0043] like Figures 1 to 4As shown, in generator-only charging mode, with the generator connected to interface 51 and the battery connected to interface 61, the first step is as follows: Before charging, the capacitor energy is discharged through the pre-charge / discharge unit. The main control chip enables the Dsicharge_EN pin, and the switch Q1 is turned on. The photovoltaic input capacitor C1 is discharged through circuit 7 via the first resistor R1 and the first diode D1; the generator input capacitor C2 is discharged through circuit 8 via the second resistor R2 and the second diode D2; and the battery input capacitor C3 is discharged through circuit 9 via the third resistor R3 and the third diode D3. After the voltages of the photovoltaic input capacitor C1, the generator input capacitor C2, and the battery input capacitor C3 are discharged to a consistent voltage, the main control chip disables the Dsicharge_EN pin. The second step is to pre-charge the battery input capacitor C3. The battery is pre-charged through circuit 3 via the battery pre-charge switch K6 and the third resistor R3. After pre-charging is completed, the battery input switch K5 is turned on. At this time, there is no surge current, and the opening is safe and reliable. Moreover, the battery input switch K5 can be a lower-cost device. Step 3: Turn on the first NMOS transistor Q2 and the second NMOS transistor Q3. Since the voltages of the photovoltaic input capacitor C1 and the generator input capacitor C2 are the same, there is no inrush current when turning on the first NMOS transistor Q2 and the second NMOS transistor Q3, ensuring safe and reliable startup. Furthermore, the first NMOS transistor Q2 and the second NMOS transistor Q3 can be lower-cost NMOS transistors. At this moment, the photovoltaic input capacitor C1 and the generator input capacitor C2 are essentially connected in parallel. Step 4: Turn on the generator pre-charge switch K4. The generator charges the battery input capacitor C3 and the generator input capacitor C2 simultaneously through circuit 2 and the second resistor R2. After charging is complete, turn on the generator input switch K3. There is no inrush current at this time, ensuring safe and reliable startup. Furthermore, the generator input switch K3 can be a lower-cost device. Step 5: Control the soft switching and soft-start waveform generation of the first H-bridge power unit 20 and the second H-bridge power unit 30, achieving current-free operation throughout the process. Furthermore, lower-cost NMOS transistors can be selected for each process.

[0044] like Figures 1 to 4As shown, in the hybrid charging mode, with photovoltaic interface 41 connected to the photovoltaic system, generator interface 51 connected to the generator, and battery interface 61 connected to the battery, the first step is as follows: Before charging, the capacitor energy is discharged through the pre-charge / discharge unit. The main control chip enables the Dsicharge_EN pin, and the switch Q1 is turned on. The photovoltaic input capacitor C1 is discharged through circuit 7 via the first resistor R1 and the first diode D1; the generator input capacitor C2 is discharged through circuit 8 via the second resistor R2 and the second diode D2; and the battery input capacitor C3 is discharged through circuit 9 via the third resistor R3 and the third diode D3. After the voltages of the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 are discharged to a consistent voltage, the main control chip disables the Dsicharge_EN pin. The second step is to pre-charge the battery input capacitor C3. The battery is pre-charged through circuit 3 via the battery pre-charge switch K6 and the third resistor R3. After pre-charging is completed, the battery input switch K5 is turned on. At this time, there is no surge current, and the opening is safe and reliable. Moreover, the battery input switch K5 can be a lower-cost device. Step 3: Disconnect the first NMOS transistor Q2 and the second NMOS transistor Q3 due to power failure. Step 4: Turn on the photovoltaic pre-charge switch K2 and the generator pre-charge switch K4. The photovoltaic power supply charges the photovoltaic input capacitor C1 through circuit 1 via the first resistor R1, and the generator power supply charges the generator input capacitor C2 through circuit 2 via the second resistor R2. After charging is complete, turn on the photovoltaic input switch K1 and the generator input switch K3. At this time, there is no inrush current, and the start-up is safe and reliable. Furthermore, lower-cost components can be selected for the photovoltaic input switch K1 and the generator input switch K3. Step 5: Control the soft switching and soft-start waveform generation of the first H-bridge power unit 20 and the second H-bridge power unit 30 to achieve current stress-free operation throughout the process. Lower-cost NMOS transistors can also be selected for each process.

[0045] This application also provides a charging controller. The charging controller includes a housing, a circuit board, and a charging control circuit as described above. The charging control circuit is disposed on the circuit board, which is located inside the housing. This charging controller has the same structure and beneficial effects as the charging control circuit in the foregoing embodiments. The structure and beneficial effects of the charging control circuit have been described in detail in the foregoing embodiments and will not be repeated here.

[0046] The charging control circuit and charging controller of this application embodiment can reliably, stably, and efficiently charge the battery, and can automatically switch between two input sources, safely pre-charge the capacitor, and quickly pre-discharge the capacitor in a single circuit, solving the problems of complex circuits, high cost, and low reliability of traditional solutions. Through a simplified and reliable pre-charge and discharge unit, intelligent voltage equalization control, and multiple safety protections, it effectively solves the problems of surge current impact, short circuit risk, and maintenance safety in traditional solutions, making it particularly suitable for applications such as off-grid power supply systems, emergency power supplies, and power supply in remote areas where reliability and safety requirements are extremely high.

[0047] This application also provides a charging control method, applied to the charging control circuit described above. Figures 1 to 5 As shown, the charging control method includes: S110 controls the switch Q1 to discharge the photovoltaic input capacitor C1, generator input capacitor C2 and battery input capacitor C3 through the pre-charge and discharge unit 80. After the discharge is completed, the switch Q1 is turned off. S120: Control the battery precharge switch K6 to precharge the battery input capacitor C3. After the precharge is completed, turn on the battery input switch K5. S130. Control the on / off state of the switch assembly 70 according to the preset charging mode. The preset charging modes include photovoltaic charging mode only, generator charging mode only, and hybrid charging mode. S140. Control the on / off state of photovoltaic pre-charge switch K2 and generator pre-charge switch K4 according to the preset charging mode to charge photovoltaic input capacitor C1 and / or generator input capacitor C2. After charging is completed, connect photovoltaic input switch K1 or generator input switch K3 accordingly. S150 controls the first H-bridge power unit 20 and the second H-bridge power unit 30 to operate, so as to charge the battery connected to the battery interface 61.

[0048] The charging control method of this application embodiment achieves pre-discharge by connecting a common switch Q1 and discharging the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 through the pre-charge and discharge unit 80. This simplifies the circuit structure and effectively releases the residual voltage of each input capacitor. Furthermore, before the battery is officially charged, the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 are pre-charged by their corresponding pre-charge switches. Since the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 can be pre-discharged and pre-charged, the possibility of surge current generation is reduced when the photovoltaic input switch K1, generator input switch K3, and switch assembly 70 are turned on, improving the safety and reliability of the circuit during start-up and shutdown and reducing safety hazards. Because the surge current is effectively suppressed, the tolerance requirements of the photovoltaic input switch K1, generator input switch K3, and switch assembly 70 are reduced, and lower-cost general-purpose devices can be used instead of high-performance dedicated devices, resulting in a lower overall cost.

[0049] Specifically, in step S110, when switch Q1 is turned on, the residual electrical energy from the photovoltaic input capacitor C1, generator input capacitor C2, and battery input capacitor C3 after shutdown is discharged to ground through the pre-charge / discharge unit 80. Once the voltages of these capacitors drop to a safe threshold, indicating completion of the discharge process, switch Q1 is turned off. This eliminates residual high voltage in the capacitors, preventing large current surges when the switch is closed subsequently, thus protecting the relevant switching devices and the battery.

[0050] In step S120, after each input capacitor has discharged, the battery precharge switch K6 is turned on to perform soft charging on the battery input capacitor C3 connected in parallel to the voltage output terminals of the first H-bridge power unit 20 and the second H-bridge power unit 30. After the voltage of the battery input capacitor C3 matches the battery voltage, the battery input switch K5 is turned on to complete the battery side connection preparation. There is no surge current when the battery input switch K5 is turned on, and the opening time is safe and reliable. In addition, the battery input switch K5 can be selected from lower cost devices.

[0051] In step S130, in a specific embodiment, when the preset charging mode is photovoltaic charging mode only or generator charging mode only, the switching component 70 is turned on. At this time, because the voltages of the generator input capacitor C2 and the battery input capacitor C3 are the same, there is no surge current when the switching component 70 is turned on, ensuring safe and reliable operation. Furthermore, the switching component 70 can use a lower-cost switching transistor Q1. At this moment, the generator input capacitor C2 and the battery input capacitor C3 are essentially connected in parallel. When the preset charging mode is hybrid charging mode, the switching component 70 is always turned off. This allows for independent adjustment of the operating parameters of the first H-bridge power unit 20 and the second H-bridge power unit 30 based on the real-time power output of the photovoltaic and generator components, improving overall energy utilization efficiency. It also avoids voltage conflicts between the two input sources, enhancing charging safety.

[0052] In step S140, in a specific embodiment, when the preset charging mode is photovoltaic charging only, the photovoltaic pre-charge switch K2 is turned on to charge the photovoltaic input capacitor C1 and the generator input capacitor C2. After charging is completed, the photovoltaic input switch K1 is turned on. At this time, there is no surge current, the start-up is safe and reliable, and the photovoltaic input switch K1 can be selected with lower-cost components. When the preset charging mode is generator charging only, the generator pre-charge switch K4 is turned on to charge the photovoltaic input capacitor C1 and the generator input capacitor C2. After charging is completed, the generator input switch K3 is turned on. At this time, there is no surge current, the start-up is safe and reliable, and the generator input switch K3 can be selected with lower-cost components. When the preset charging mode is hybrid charging, the photovoltaic pre-charge switch K2 and the generator pre-charge switch K4 are turned on to charge the photovoltaic input capacitor C1 and the generator input capacitor C2 respectively. After completion, the photovoltaic input switch K1 and the generator input switch K3 are turned on. At this time, there is no surge current, the start-up is safe and reliable, and the photovoltaic input switch K1 and the generator input switch K3 can be selected with lower-cost components.

[0053] In step S150, in a specific embodiment, when controlling the first H-bridge power unit 20 and the second H-bridge power unit 30 to work, the NMOS transistors of the first H-bridge power unit 20 and the second H-bridge power unit 30 are controlled to soft-switch and soft-start waveform, so that there is no current stress in the whole process, and each NMOS transistor can be a lower cost NMOS transistor.

[0054] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A charging control circuit, characterized in that, It includes a main control unit, a first H-bridge power unit, a second H-bridge power unit, a photovoltaic access unit, a generator access unit, a battery access unit, a switching assembly, a pre-charge and discharge unit, and a switching transistor; The photovoltaic access unit includes a photovoltaic interface, a photovoltaic input capacitor, a photovoltaic input switch, and a photovoltaic pre-charge switch. The photovoltaic input capacitor is connected in parallel to the voltage input terminal of the first H-bridge power unit. The photovoltaic input switch and the photovoltaic pre-charge switch are both located between the photovoltaic interface and the photovoltaic input capacitor. The generator access unit includes a generator interface, a generator input capacitor, a generator input switch, and a generator precharge switch. The generator input capacitor is connected in parallel to the voltage input terminal of the second H-bridge power unit. The generator input switch and the generator precharge switch are both located between the generator interface and the generator input capacitor. The battery access unit includes a battery interface, a battery input capacitor, a battery input switch, and a battery precharge switch. The battery input capacitor is connected in parallel to the voltage output terminals of the first H-bridge power unit and the second H-bridge power unit. The battery input switch and the battery precharge switch are both located between the battery interface and the battery input capacitor. The photovoltaic input capacitor, the generator input capacitor, and the battery input capacitor are connected to the first terminal of the switching transistor through the pre-charge and discharge unit, and the second terminal of the switching transistor is grounded. The switching assembly is located between the voltage input terminal of the first H-bridge power unit and the voltage input terminal of the second H-bridge power unit. The main control unit is used to control the working status of the photovoltaic input switch, the photovoltaic precharge switch, the battery precharge switch, the battery input switch, the generator input switch, the generator precharge switch, the precharge and discharge unit, and the switching transistor, so as to charge the battery connected to the battery interface.

2. The charging control circuit according to claim 1, characterized in that, The pre-charge / discharge unit includes a first pre-discharge branch, a second pre-discharge branch, and a third pre-discharge branch. The photovoltaic input capacitor is connected to the first terminal of the switching transistor through the first pre-discharge branch; the generator input capacitor is connected to the first terminal of the switching transistor through the second pre-discharge branch; and the battery input capacitor is connected to the first terminal of the switching transistor through the third pre-discharge branch.

3. The charging control circuit according to claim 2, characterized in that, The first pre-charge branch includes a first resistor and a first diode. The first resistor is connected in series between the photovoltaic pre-charge switch and the positive terminal of the photovoltaic input capacitor. The positive terminal of the first diode is connected to the first resistor, and its negative terminal is connected to the first terminal of the switching transistor.

4. The charging control circuit according to claim 2, characterized in that, The second pre-charge branch includes a second resistor and a second diode. The second resistor is connected in series between the generator pre-charge switch and the positive terminal of the generator input capacitor. The positive terminal of the second diode is connected to the second resistor, and its negative terminal is connected to the first terminal of the switching transistor.

5. The charging control circuit according to claim 2, characterized in that, The third pre-charge branch includes a third resistor and a third diode. The third resistor is connected in series between the battery pre-charge switch and the positive terminal of the battery input capacitor. The positive terminal of the third diode is connected to the third resistor, and its negative terminal is connected to the first terminal of the switching transistor.

6. The charging control circuit according to any one of claims 1-5, characterized in that, The photovoltaic input switch, the photovoltaic pre-charge switch, the battery pre-charge switch, the battery input switch, and the generator input switch are all relays. The main control unit includes a main control chip and a Darlington transistor array. The main control chip is connected to the control terminals of the switching transistor, the first H-bridge power unit, the second H-bridge power unit, and the switching assembly. The signal input terminal of the Darlington transistor array is connected to the main control chip, and its power output terminal is connected to the control terminals of each of the relays.

7. The charging control circuit according to claim 6, characterized in that, The charging control circuit also includes a drive protection unit connected to the switching transistor. The drive protection unit includes a fourth resistor, a fifth resistor, and a discharge capacitor. The fourth resistor is connected in series between the main control chip and the control terminal of the switching transistor. The fifth resistor is connected in parallel with the discharge capacitor and is arranged in parallel between the control terminal and the second terminal of the switching transistor.

8. The charging control circuit according to any one of claims 1-5, characterized in that, The switching assembly includes a first NMOS transistor and a second NMOS transistor. The source of the first NMOS transistor is connected to the source of the second NMOS transistor. The drain of the first NMOS transistor is connected to the voltage input terminal of the first H-bridge power unit. The drain of the second NMOS transistor is connected to the voltage input terminal of the second H-bridge power unit. The gates of the first NMOS transistor and the second NMOS transistor are both connected to the main control unit.

9. A charging controller, characterized in that, It includes a housing, a circuit board, and a charging control circuit as described in any one of claims 1-8, wherein the charging control circuit is disposed on the circuit board, and the circuit board is disposed inside the housing.

10. A charging control method, characterized in that, The charging control method, applied to the charging control circuit as described in any one of claims 1-8, comprises: The switch is turned on to discharge the photovoltaic input capacitor, the generator input capacitor, and the battery input capacitor through the pre-charge and discharge unit. After the discharge is completed, the switch is turned off. Control the battery precharge switch to turn on, precharge the battery input capacitor, and turn on the battery input switch after the precharge is completed; The on / off state of the switching component is controlled according to a preset charging mode, which includes a photovoltaic charging mode only, a generator charging mode only, and a hybrid charging mode. The on / off states of the photovoltaic pre-charge switch and the generator pre-charge switch are controlled according to the preset charging mode to charge the photovoltaic input capacitor and / or the generator input capacitor. After charging is completed, the photovoltaic input switch or the generator input switch is turned on accordingly. The first H-bridge power unit and the second H-bridge power unit are controlled to operate in order to charge the battery connected to the battery interface.

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