Maximum power point tracking circuit, power device and new energy system

Abstract

The embodiment of the present application discloses a kind of maximum power point tracking circuits.The MPPT circuit includes: voltage reduction circuit, MPPT control circuit, MPPT auxiliary source trigger circuit, auxiliary source starting circuit and MPPT auxiliary source circuit.MPPT auxiliary source trigger circuit generates auxiliary source trigger signal in response to the photovoltaic voltage of photovoltaic module being greater than the battery voltage of battery.Auxiliary source starting circuit outputs the photovoltaic voltage of photovoltaic module in response to the input of auxiliary source trigger signal.MPPT auxiliary source circuit enters working state in response to the input of photovoltaic voltage.The embodiment of the present application does not need the participation of microcontroller of power equipment, and can still activate MPPT auxiliary source circuit to enter working state independently when power equipment is in shutdown state or standby state, is not affected by the working state of power equipment, so as to improve the working reliability of MPPT circuit.

Description

Technical Field

[0001] This application relates to the field of new energy technology, specifically to a maximum power point tracking circuit, power equipment, and a new energy system. Background Technology

[0002] Maximum Power Point Tracking (MPPT) circuits monitor the output power of photovoltaic (PV) modules in real time and adjust the operating voltage and current of the PV modules based on the output power, ensuring that the PV modules always operate near their maximum power point, thereby improving the power generation efficiency of the PV modules. Typically, the electrical energy output by the PV modules is transferred to the batteries of UPS (Uninterruptible Power Supply) equipment for storage, and the PV modules charge the batteries.

[0003] The relevant technology uses the microcontroller of the UPS equipment to detect the photovoltaic voltage of the photovoltaic module and the battery voltage. When the photovoltaic voltage of the photovoltaic module is greater than the battery voltage, the microcontroller of the UPS equipment controls the MPPT auxiliary power circuit to enter the working state, so as to provide the necessary operating power to the MPPT controller and other circuits. This method can only be implemented when the UPS equipment is running. When the UPS equipment is in a stopped or standby state, the microcontroller of the UPS equipment is not working. Therefore, the controller of the UPS equipment cannot activate the MPPT auxiliary power circuit to enter the working state, resulting in the MPPT circuit not being able to transfer the electrical energy output from the photovoltaic module to the battery for storage in a timely manner. Summary of the Invention

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a power switch circuit, a power amplifier, and an electronic device to solve the technical problem of unreliable operation of MPPT circuits provided in related technologies.

[0005] In a first aspect, embodiments of this application provide a maximum power point tracking (MPPT) circuit, including: a buck circuit, an MPPT control circuit, an MPPT auxiliary source trigger circuit, an auxiliary source start-up circuit, and an MPPT auxiliary source circuit. The buck circuit is electrically connected between the photovoltaic module and the battery of the power equipment. The MPPT control circuit is electrically connected to the buck circuit. The MPPT auxiliary source trigger circuit is electrically connected between the positive terminal of the photovoltaic module and the positive terminal of the battery, and is configured to generate an auxiliary source trigger signal in response to the photovoltaic voltage of the photovoltaic module being greater than the battery voltage. The auxiliary source start-up circuit is electrically connected to both the MPPT auxiliary source trigger circuit and the photovoltaic module, and is configured to output the photovoltaic voltage of the photovoltaic module in response to the input of the auxiliary source trigger signal. The MPPT auxiliary source circuit is electrically connected to the auxiliary source start-up circuit and is configured to enter a working state in response to the input of the photovoltaic voltage.

[0006] This application embodiment does not require the participation of the microcontroller of the power equipment. Even when the power equipment is in a shutdown or standby state, it can still autonomously activate the MPPT auxiliary power circuit to enter the working state, unaffected by the working state of the power equipment, thus improving the working reliability of the MPPT circuit.

[0007] Optionally, the MPPT auxiliary power trigger circuit includes an optocoupler primary circuit and an optocoupler secondary circuit. The optocoupler primary circuit is electrically connected between the positive terminal of the photovoltaic module and the positive terminal of the battery, and is configured to emit an optocoupler signal in response to the photovoltaic voltage of the photovoltaic module being greater than the battery voltage. The optocoupler secondary circuit is coupled to the optocoupler primary circuit and is also electrically connected to the auxiliary power start-up circuit, and is configured to generate an auxiliary power trigger signal in response to the input of the optocoupler signal.

[0008] This application embodiment utilizes only a low-cost optocoupler as the main component of the MPPT auxiliary source trigger circuit, which enables the detection and comparison between photovoltaic voltage and battery voltage, thereby reliably triggering the auxiliary source start-up circuit to operate.

[0009] Optionally, the auxiliary power supply startup circuit includes a first switching circuit and a second switching circuit. The first switching circuit includes a first node and a second node. The first switching circuit is electrically connected to the MPPT auxiliary power supply trigger circuit and also electrically connected to the MPPT auxiliary power supply circuit at the second node. It is configured to respond to the input of the auxiliary power supply trigger signal, enter a conducting state, and pull down the first voltage of the first node. The second switching circuit includes a third node, which is electrically connected to the first switching circuit at the first node and electrically connected to the positive terminal of the photovoltaic module at the third node. It is configured to, under the action of the photovoltaic voltage and the pulled-down first voltage, transmit the photovoltaic voltage to the MPPT auxiliary power supply circuit via the second node through the first switching circuit in the conducting state.

[0010] Optionally, the first switching circuit includes a first PMOS transistor, the gate of which is configured to receive an auxiliary source trigger signal, the source of which is electrically connected to a first node, and the drain of which is electrically connected to a second node.

[0011] Optionally, the first switching circuit includes a first PNP transistor, the base of which is configured to receive an auxiliary source trigger signal, the emitter is electrically connected to a first node, and the collector is electrically connected to a second node.

[0012] Optionally, the second switching circuit includes a Zener diode, a first NPN transistor, and a first diode. The negative terminal of the Zener diode is electrically connected to the base of the first NPN transistor and is configured to receive photovoltaic voltage. The positive terminal of the Zener diode is electrically connected to the negative terminal of the photovoltaic module. The collector of the first NPN transistor is configured to receive photovoltaic voltage. The emitter of the first NPN transistor is electrically connected to the first node. The positive terminal of the first diode is electrically connected to the first node, and the negative terminal of the first diode is electrically connected to the base of the first NPN transistor.

[0013] The Zener diode handles the photovoltaic voltage, providing a stable base voltage for the first NPN transistor and preventing excessive base voltage from damaging it, thus maintaining the transistor's operational stability. When the power equipment is in shutdown or standby mode, and the battery's charge is released through the step-down circuit, the Zener diode and the first diode prevent the battery's charge from being discharged to ground, thus avoiding complete battery depletion.

[0014] Optionally, the maximum power point tracking circuit further includes a voltage feedback circuit, which is electrically connected to the MPPT auxiliary power supply circuit and also electrically connected to the second node. The voltage feedback circuit is configured to feed back the auxiliary power supply voltage of the MPPT auxiliary power supply circuit to the first switching circuit, so that the first switching circuit enters the off state and cuts off the power supply loop from the photovoltaic module to the MPPT auxiliary power supply circuit.

[0015] The auxiliary power supply voltage provided in this embodiment is directly transmitted from the second node to the MPPT auxiliary power supply circuit without any power loss, thereby saving energy and improving the utilization rate of photovoltaic energy.

[0016] Optionally, the voltage feedback circuit includes a second diode, the positive terminal of which is electrically connected to the MPPT auxiliary power supply circuit, and the negative terminal of which is electrically connected to the second node.

[0017] Optionally, the MPPT control circuit includes a switch drive circuit and an MPPT controller. The switch drive circuit is electrically connected to the MPPT auxiliary power circuit and the step-down circuit, respectively. The MPPT controller is electrically connected to the switch drive circuit and is configured to control the switch drive circuit to drive the step-down circuit to perform a step-down operation.

[0018] Optionally, the switch drive circuit includes a drive protection circuit and a drive control circuit. The drive protection circuit is electrically connected to the MPPT auxiliary power supply circuit and is configured to output the auxiliary power supply voltage of the MPPT auxiliary power supply circuit in response to the auxiliary power supply voltage being within the normal voltage range, or to stop outputting the auxiliary power supply voltage of the MPPT auxiliary power supply circuit in response to the auxiliary power supply voltage deviating from the normal voltage range. The drive control circuit is electrically connected to both the drive protection circuit and the MPPT controller and is configured to be controlled by the MPPT controller to transmit the auxiliary power supply voltage to the buck circuit to drive the buck circuit to perform a buck operation.

[0019] Optionally, the maximum power point tracking circuit further includes an auxiliary source feedback circuit, which is electrically connected to the MPPT auxiliary source circuit and configured to send a voltage feedback signal to the MPPT auxiliary source circuit based on the auxiliary source voltage and a preset voltage threshold, so that the MPPT auxiliary source circuit adjusts the auxiliary source voltage based on the voltage feedback signal.

[0020] The embodiments of this application, through the auxiliary source feedback circuit, can ensure that the MPPT auxiliary source circuit outputs a reliable and accurate auxiliary source voltage.

[0021] In a second aspect, embodiments of this application provide a power device including the maximum power point tracking circuit described above.

[0022] In a third aspect, embodiments of this application provide a new energy system, including a photovoltaic module, the aforementioned maximum power point tracking circuit, and power equipment, wherein the maximum power point tracking circuit is electrically connected between the photovoltaic module and the battery of the power equipment. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 A schematic diagram of a circuit structure between a power device and an MPPT circuit, provided for related technologies;

[0025] Figure 2 A schematic diagram of another circuit structure between a power device and an MPPT circuit, provided for related technologies;

[0026] Figure 3 This application provides a schematic diagram of the circuit structure of a new energy system according to an embodiment of the present application.

[0027] Figure 4 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in an embodiment of this application;

[0028] Figure 5 for Figure 4 The circuit structure diagram of the step-down circuit shown is shown.

[0029] Figure 6 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided for another embodiment of this application;

[0030] Figure 7 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0031] Figure 8 for Figure 7 The circuit structure diagram of the drive protection circuit and drive control circuit shown is shown.

[0032] Figure 9 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0033] Figure 10 for Figure 9 The circuit structure diagram of the primary and secondary circuits of the optocoupler is shown.

[0034] Figure 11 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0035] Figure 12 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0036] Figure 13 The circuit structure diagram of the flyback power supply circuit, the first-stage buck circuit, the second-stage buck circuit, and the voltage feedback circuit shown in Figure 12 is as follows:

[0037] Figure 14 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0038] Figure 15 A schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application;

[0039] Figure 16 for Figure 15 The circuit structure diagram of the auxiliary source feedback circuit is shown.

[0040] Figure 17 This is a schematic diagram of the circuit structure of a maximum power point tracking circuit provided in another embodiment of this application. Detailed Implementation

[0041] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "electrically connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Furthermore, technical features involved in the different embodiments of the invention described below may be combined with each other as long as they do not conflict with each other.

[0043] The inventors have discovered that the following two related technologies have corresponding technical problems, as follows:

[0044] Related technologies ①. Please refer to [link / reference]. Figure 1 The power equipment 100 includes a power factor correction circuit 11 (PFC), a bus circuit 12, an inverter circuit 13, a DC-DC circuit 14, a battery 15, and a microprocessor 16. The power factor correction circuit 11 is electrically connected to the bus circuit 12, the bus circuit 12 is electrically connected to the inverter circuit 13, the DC-DC circuit 14 is electrically connected to the bus circuit 12, and the battery 15 is electrically connected to the DC-DC circuit 14. The microprocessor 16 is electrically connected to the power factor correction circuit 11, the inverter circuit 13, the DC-DC circuit 14, and the battery 15, and is used to detect the battery voltage of the battery 15. The battery 15 has a first battery terminal 17.

[0045] The MPPT circuit 200 includes a photovoltaic terminal block 21, an MPPT auxiliary power module 22, an MPPT power module 23, an MPPT main circuit 24, and a second battery terminal block 25. The photovoltaic terminal block 21 is used for electrical connection to the photovoltaic module 26. The MPPT auxiliary power module 22 is electrically connected to the photovoltaic terminal block 21. The MPPT power module 23 is electrically connected to both the photovoltaic terminal block 21 and the second battery terminal block 25. The MPPT main circuit 24 is electrically connected to the MPPT auxiliary power module 22. The second battery terminal block 25 is used for electrical connection to the first battery terminal block 17.

[0046] The microcontroller 16 is electrically connected to the photovoltaic terminal 21 and the MPPT auxiliary power module 22. When the microcontroller 16 detects that the photovoltaic voltage of the photovoltaic module 26 is greater than the battery voltage of the battery 15, the microcontroller 16 controls the MPPT auxiliary power module 22 to enter the working state. However, when the power equipment 100 is in a shutdown or standby state, the microcontroller 16 does not work, thus preventing the MPPT auxiliary power module 22 from entering the working state.

[0047] Related technology ②. Please refer to [link / reference]. Figure 2 The difference between related technology ② and related technology ① is that the microcontroller 16 of the power equipment 100 no longer needs to sample the photovoltaic voltage and battery voltage. Related technology ② adds a voltage detection module 27, which is used to detect the photovoltaic voltage and compare it with a preset voltage threshold. When the photovoltaic voltage is greater than the preset voltage threshold, the MPPT auxiliary power module 22 is controlled to enter the working state. However, when the power equipment 100 is in a shutdown or standby state, the power of the battery 15 can easily supply power to the MPPT auxiliary power module 22 through the body diode of the main switch of the MPPT power module 23, resulting in the loss of power from the battery 15.

[0048] This embodiment of the application does not require the participation of the microcontroller of the power equipment. Even when the power equipment is in a shutdown or standby state, it can still autonomously activate the MPPT auxiliary power circuit to enter the working state, unaffected by the working state of the power equipment, thus improving the working reliability of the MPPT circuit. When the photovoltaic module is not connected to the MPPT circuit, this embodiment of the application can block the loop of the battery releasing a small current through the body diode of the step-down circuit, avoiding unnecessary consumption of battery power.

[0049] The following embodiments of this application provide a new energy system. Please refer to... Figure 3The new energy system 300 includes a photovoltaic module 400, a maximum power point tracking circuit 500 (MPPT circuit), and a power equipment 600. The MPPT circuit 500 is electrically connected between the photovoltaic module 400 and the battery of the power equipment 600. The MPPT circuit 500 can monitor the output power of the photovoltaic module 400 and adjust the operating voltage and current of the photovoltaic module 400 based on the output power, so that the photovoltaic module 400 always operates near the maximum power point, which can efficiently convert light energy into electrical energy and transmit the electrical energy to the battery of the power equipment 600 for storage.

[0050] Please see Figure 4 The maximum power point tracking circuit 500 includes a step-down circuit 51, an MPPT control circuit 52, an MPPT auxiliary source trigger circuit 53, an auxiliary source start-up circuit 54, and an MPPT auxiliary source circuit 55.

[0051] The step-down circuit 51 is electrically connected between the photovoltaic module 400 and the battery of the power equipment 600. It is used to step down the photovoltaic voltage output by the photovoltaic module 400 to obtain a stepped-down photovoltaic voltage, which is then supplied to the battery of the power equipment 600 for energy storage. It can be understood that the step-down topology of the step-down circuit 51 is customized by the designer according to business requirements.

[0052] Please see Figure 5 The step-down circuit 51 includes a first capacitor C1, a second capacitor C2, a first NMOS transistor NQ1, a first resistor R1, a second resistor R2, a diode J1, a diode J2, and a first inductor L1. The MPPT control circuit 52 controls the first NMOS transistor NQ1 to enter either a conducting or turning-off state according to the step-down mode, so that the first capacitor C1, the second capacitor C2, the first NMOS transistor NQ1, the first resistor R1, the second resistor R2, the diodes J1 and J2, and the first inductor L1 work together to complete the step-down operation.

[0053] MPPT control circuit 52 is electrically connected to buck circuit 51. MPPT control circuit 52 serves as the control core of maximum power point tracking circuit 500. It can not only control buck circuit 51 to perform buck operation, but also control the working status of other circuits.

[0054] Please see Figure 6The MPPT control circuit 52 includes a switch drive circuit 521 and an MPPT controller 522. The switch drive circuit 521 is electrically connected to the MPPT auxiliary power supply circuit 55 and the buck circuit 51, respectively. The MPPT controller 522 is electrically connected to the switch drive circuit 521 and is used to control the switch drive circuit 521 to drive the buck circuit 51 to perform a buck operation. Specifically, the MPPT controller 522 sends a drive enable signal to the switch drive circuit 521, and the switch drive circuit 521, driven by the drive enable signal, drives the buck circuit 51 to perform the buck operation. The MPPT controller 522 supports the MPPT control algorithm and controls and coordinates the operating states of each circuit according to the MPPT control algorithm.

[0055] Please see Figure 7 The switch drive circuit 521 includes a drive protection circuit 523 and a drive control circuit 524. The drive protection circuit 523 is electrically connected to the MPPT auxiliary power supply circuit 55 and is used to output the auxiliary power supply voltage of the MPPT auxiliary power supply circuit 55 when the auxiliary power supply voltage of the MPPT auxiliary power supply circuit 55 is within the normal voltage range, or to stop outputting the auxiliary power supply voltage of the MPPT auxiliary power supply circuit 55 when the auxiliary power supply voltage of the MPPT auxiliary power supply circuit 55 deviates from the normal voltage range. The drive control circuit 524 is electrically connected to both the drive protection circuit 523 and the MPPT controller 522, and is controlled by the MPPT controller 522 to transmit the auxiliary power supply voltage to the buck circuit 51 to drive the buck circuit 51 to perform a buck operation.

[0056] Please see Figure 8 The drive protection circuit 523 includes a third resistor R3, an NPN transistor NS0, a first voltage regulator TL1, a fourth resistor R4, a fifth resistor R5, and a third capacitor C3.

[0057] When the voltage at the reference terminal R of the first regulator TL1 is less than the reference voltage (e.g., 2.5V), the path between the anode A and cathode E of the first regulator TL1 is broken. Since the collector of the NPN transistor NS0 is supplied with the auxiliary source voltage MPPT_VCC from the MPPT auxiliary source circuit 55, and the emitter voltage of the NPN transistor NS0 is relatively low, the NPN transistor NS0 meets the conduction condition and enters the conduction state. The auxiliary source voltage MPPT_VCC is output through the NPN transistor NS0. The third capacitor C3 filters the auxiliary source voltage MPPT_VCC output by the NPN transistor NS0.

[0058] When the auxiliary source voltage MPPT_VCC becomes abnormally large, it causes the auxiliary source voltage MPPT_VCC output by NPN transistor NS0 to also increase. This leads to the voltage division of the auxiliary source voltage MPPT_VCC output by NPN transistor NS0 after the voltage division process of the fourth resistor R4 and the fifth resistor R5. Since the reference voltage R of the first regulator TL1 is greater than the reference voltage, the path between the anode A and the cathode E of the first regulator TL1 is turned on. The voltage at the base of NPN transistor NS0 is pulled down, causing NPN transistor NS0 to fail to meet the conduction condition and enter the off state. This stops the output of the abnormal auxiliary source voltage MPPT_VCC.

[0059] Please continue reading. Figure 8 The drive control circuit 524 includes a fourth capacitor C4, a sixth resistor R6, a seventh resistor R7, an optocoupler U0, and a fifth capacitor C5. One end of the primary winding of the optocoupler U0 is supplied with a 12V voltage, and the other end is electrically connected to the MPPT controller 522. When the MPPT controller 522 inputs a low level to the other end of the primary winding of the optocoupler U0, the primary winding of the optocoupler U0 enters a conducting state, causing the secondary winding of the optocoupler U0 to also enter a conducting state. The auxiliary source voltage MPPT_VCC output by the NPN transistor NSO is applied to the gate of the first NMOS transistor NQ1 in the buck converter 51 through the secondary winding of the optocoupler U0, thereby driving the first NMOS transistor NQ1 into a conducting state. When the MPPT controller 522 inputs a high level to the other end of the primary side of the optocoupler U0, the primary side of the optocoupler U0 enters the off state, causing the secondary side of the optocoupler U0 to also enter the off state. The auxiliary source voltage MPPT_VCC output by the NPN transistor NS0 cannot be applied to the gate of the first NMOS transistor NQ1 of the buck circuit 51 through the secondary side of the optocoupler U0, and the first NMOS transistor NQ1 enters the off state.

[0060] The MPPT auxiliary power trigger circuit 53 is electrically connected between the positive terminal of the photovoltaic module 400 and the positive terminal of the battery. It generates an auxiliary power trigger signal in response to the photovoltaic voltage of the photovoltaic module 400 exceeding the battery voltage. This auxiliary power trigger signal triggers the auxiliary power start-up circuit to enter the working state. The signal type of the auxiliary power trigger signal is constrained by the circuit topology of the MPPT auxiliary power trigger circuit 53. In some embodiments, the auxiliary power trigger signal is low-level; in other embodiments, it is high-level.

[0061] Please see Figure 9The MPPT auxiliary power trigger circuit 53 includes an optocoupler primary circuit 531 and an optocoupler secondary circuit 532. The optocoupler primary circuit 531 is electrically connected between the positive terminal of the photovoltaic module 400 and the positive terminal of the battery, and is used to transmit an optocoupler signal in response to the photovoltaic voltage of the photovoltaic module 400 being greater than the battery voltage. The optocoupler secondary circuit 532 is coupled to the optocoupler primary circuit 531 and is also electrically connected to the auxiliary power start-up circuit 54, and is used to generate an auxiliary power trigger signal in response to the input of the optocoupler signal. This embodiment of the application utilizes only a low-cost optocoupler as the main component of the MPPT auxiliary power trigger circuit, which enables the detection and comparison between the photovoltaic voltage and the battery voltage, thereby reliably triggering the auxiliary power start-up circuit to operate.

[0062] Please see Figure 10 The primary-side circuit 531 of the optocoupler includes the eighth resistor R8 and the primary side of optocoupler U1. The secondary-side circuit 532 of the optocoupler includes the ninth resistor R9 and the secondary side of optocoupler U1. When the photovoltaic voltage is greater than the battery voltage, the primary side of optocoupler U1 enters the on state and emits an optocoupler signal. The secondary side of optocoupler U1 receives the optocoupler signal and enters the on state, outputting a low level (i.e., an auxiliary source trigger signal). When the photovoltaic voltage is less than or equal to the battery voltage, the primary side of optocoupler U1 enters the off state and does not emit an optocoupler signal. The secondary side of optocoupler U1 does not receive an optocoupler signal and enters the off state.

[0063] The auxiliary power start-up circuit 54 is electrically connected to the MPPT auxiliary power trigger circuit 53 and the photovoltaic module 400 respectively, and is used to respond to the input of the auxiliary power trigger signal and output the photovoltaic voltage of the photovoltaic module 400.

[0064] Please see Figure 11 The auxiliary power supply start-up circuit 54 includes a first switching circuit 541 and a second switching circuit 542. The first switching circuit includes a first node N1 and a second node N2. The first switching circuit 541 is electrically connected to the MPPT auxiliary power supply trigger circuit 53 and is electrically connected to the MPPT auxiliary power supply circuit 55 at the second node N2. It is used to respond to the input of the auxiliary power supply trigger signal, enter the conduction state, and pull down the first voltage of the first node N1.

[0065] Please continue reading. Figure 10 In some embodiments, the first switching circuit 541 includes a first PMOS transistor PQ1, the gate of which is configured to receive an auxiliary source trigger signal, the source of which is electrically connected to a first node N1, and the drain of which is electrically connected to a second node N2. In other embodiments, the first switching circuit 541 includes a first PNP transistor, the base of which is configured to receive an auxiliary source trigger signal, the emitter of which is electrically connected to a first node, and the collector of which is electrically connected to a second node.

[0066] Please continue reading. Figure 10The first switching circuit 541 also includes a sixth capacitor C6 and a tenth resistor R10. The sixth capacitor C6 can filter the harmonic signal of the first node N1, and the tenth resistor R10 is used to divide the first voltage of the first node N1.

[0067] The second switching circuit 542 includes a third node N3, which is electrically connected to the first switching circuit 541 at the first node N1 and electrically connected to the positive terminal of the photovoltaic module 400 at the third node N3. It is used to transmit the photovoltaic voltage to the MPPT auxiliary power circuit 55 via the second node N2 through the first switching circuit 541, which enters the conduction state, under the action of the photovoltaic voltage and the first voltage after being pulled down.

[0068] Please continue reading. Figure 10 The second switching circuit 542 includes a Zener diode ZD, a first NPN transistor NS1, and a first diode D1. The cathode of the Zener diode ZD is electrically connected to the base of the first NPN transistor NS1 to receive photovoltaic voltage. The anode of the Zener diode ZD is electrically connected to the cathode of the photovoltaic module 400. The collector of the first NPN transistor NS1 is used to receive photovoltaic voltage. The emitter of the first NPN transistor NS1 is electrically connected to the first node N1. The anode of the first diode D1 is electrically connected to the first node N1, and the cathode of the first diode D1 is electrically connected to the base of the first NPN transistor NS1.

[0069] Please continue reading. Figure 10 The second switching circuit 542 also includes an eleventh resistor R11 and a twelfth resistor R12, both of which are used for current limiting and voltage division.

[0070] When the photovoltaic voltage is greater than the battery voltage, the secondary side of optocoupler U1 enters the conducting state, and the gate voltage of the first PMOS transistor PQ1 is pulled low, thus turning on the first PMOS transistor PQ1 to lower the first voltage of the first node N1. When the first voltage of the first node N1 is pulled low, the voltage difference between the base and emitter of the first NPN transistor NS1 is close to or equal to the breakdown voltage of the Zener diode ZD, therefore, the first NPN transistor NS1 enters the conducting state. At this point, both the first NPN transistor NS1 and the first PMOS transistor PQ1 are in the conducting state. The photovoltaic voltage can then be transmitted to the MPPT auxiliary power supply circuit 55 at the second node N2 through the first NPN transistor NS1 and the first PMOS transistor PQ1 to activate the MPPT auxiliary power supply circuit 55, thus entering the operating state.

[0071] The photovoltaic voltage is not stable. The Zener diode ZD can handle the photovoltaic voltage, provide a stable base voltage for the first NPN transistor NS1, and prevent the base voltage of the first NPN transistor NS1 from being too high and damaging the first NPN transistor NS1. In this way, the operating stability of the first NPN transistor NS1 can be maintained.

[0072] When the power equipment 100 is in a shutdown or standby state, when the battery power passes through the body diode of the first NMOS transistor NQ1 in the step-down circuit 51, the Zener diode ZD and the first diode D1 can block the battery power from passing through the body diode of the first NMOS transistor NQ1 to the ground terminal, thus preventing the battery 15 from being completely depleted.

[0073] When the photovoltaic voltage is less than or equal to the battery voltage, the secondary side of the optocoupler U1 enters the off state, the voltage of the first node N1 is raised, the gate voltage of the first PMOS transistor PQ1 is raised, the first PMOS transistor PQ1 enters the off state, and the first NPN transistor NS1 also enters the off state. The photovoltaic voltage cannot be transmitted to the MPPT auxiliary power circuit 55 through the first NPN transistor NS1 and the first PMOS transistor PQ1, and the MPPT auxiliary power circuit 55 cannot be activated.

[0074] The MPPT auxiliary power supply circuit 55 is electrically connected to the auxiliary power supply startup circuit 54. It is used to respond to the input of photovoltaic voltage and enter the working state. That is, the MPPT auxiliary power supply circuit 55 is activated by the photovoltaic voltage and enters the working state. When the MPPT auxiliary power supply circuit 55 enters the working state, it can use the photovoltaic voltage as input and output the auxiliary power supply voltage. This auxiliary power supply voltage can provide the MPPT controller 522 and other peripheral circuits to ensure that the MPPT controller 522 and other peripheral circuits can work normally.

[0075] Designers can customize the circuit topology and operating mode of the MPPT auxiliary power supply circuit 55 according to business requirements. In some embodiments, the MPPT auxiliary power supply circuit 55 operates in forward power supply mode, while in other embodiments, it operates in flyback power supply mode.

[0076] Please see Figure 12 The MPPT auxiliary power supply circuit 55 adopts a flyback power supply mode. The MPPT auxiliary power supply circuit 55 includes a flyback power supply circuit 551, a first-stage buck circuit 552, and a second-stage buck circuit 553.

[0077] The flyback power supply circuit 551 is electrically connected to the first-stage buck circuit 552 and is used to output a first-type auxiliary source voltage according to the photovoltaic voltage. The first-type auxiliary source voltage is 12V or 15V, etc.

[0078] Please see Figure 13The flyback power supply circuit 551 includes a power control chip U2, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, diodes J3, J4, and J5, an NMOS transistor NQ2, and a transformer T1. The power control chip U2 controls the NMOS transistor NQ2 according to the flyback power supply mode, causing the transformer T1 to operate in flyback power supply mode to output a type-1 auxiliary source voltage.

[0079] The first-stage step-down circuit 552 includes resistors R21 (21st), R22 (22nd), R23 (23rd), R24 (24th), R25 (25th), capacitors C13 (13th), C14 (14th), C15 (15th), C16 (16th), C17 (17th), C18 (18th), and C19 (19th), a second inductor L2, and a first step-down chip U3.

[0080] The first step-down chip U3, through the peripheral circuit composed of the aforementioned resistors, capacitors, and inductors, can step down the first type of auxiliary source voltage to obtain the second type of auxiliary source voltage. For example, the first step-down chip U3 can reduce the 12V first type of auxiliary source voltage to the 5V second type of auxiliary source voltage.

[0081] The second-stage buck circuit 553 includes a second buck chip U4, a twentieth capacitor C20, and a twenty-first capacitor C21. The second buck chip U4, through the peripheral circuit composed of these capacitors, can step down the second type of auxiliary source voltage to obtain a third type of auxiliary source voltage. For example, the second buck chip U4 can reduce a 5V second type of auxiliary source voltage to a 3.3V third type of auxiliary source voltage.

[0082] In this embodiment, the MPPT auxiliary power supply circuit 55 is configured as a multi-stage step-down circuit topology, which can output different auxiliary power supply voltages to meet the different voltage requirements of various devices.

[0083] Please see Figure 14 The maximum power point tracking circuit 500 also includes a voltage feedback circuit 56, which is electrically connected to the MPPT auxiliary power supply circuit 55 and also electrically connected to the second node N2. The voltage feedback circuit 56 is used to feed back the auxiliary power supply voltage of the MPPT auxiliary power supply circuit 55 to the first switching circuit 541, so that the first switching circuit 541 enters the off state and cuts off the power supply circuit from the photovoltaic module 400 to the MPPT auxiliary power supply circuit 55.

[0084] Specifically, the voltage feedback circuit 56 feeds back the auxiliary source voltage to the first switching circuit 541. Both the first switching circuit 541 and the second switching circuit 542 switch from the on state to the off state, so the photovoltaic voltage cannot be output to the MPPT auxiliary source circuit 55 through the second switching circuit 542 and the first switching circuit 541.

[0085] Please combine Figure 10 As mentioned earlier, when the photovoltaic voltage is greater than the battery voltage, the photovoltaic voltage can be transmitted to the MPPT auxiliary power supply circuit 55 through the first NPN transistor NS1 and the first PMOS transistor PQ1 at the second node N2 to activate the MPPT auxiliary power supply circuit 55. However, due to the presence of the twelfth resistor R12 and the switching losses of the first NPN transistor NS1 and the first PMOS transistor PQ1, the energy corresponding to the photovoltaic voltage is weakened or wasted. In this embodiment, the auxiliary source voltage of the MPPT auxiliary source circuit 55 is fed back to the first PMOS transistor PQ1. Since the auxiliary source voltage is greater than the breakdown voltage of the Zener diode ZD, the first NPN transistor NS1 enters the off state. At the same time, the first PMOS transistor PQ1 also enters the off state. At this time, the auxiliary source voltage is output to the power control chip U2 of the MPPT auxiliary source circuit 55 at the second node N2 to maintain the power control chip U2 in normal operation. Thus, after the path switching operation, the photovoltaic voltage does not pass through the twelfth resistor R12, the first NPN transistor NS1 and the first PMOS transistor PQ1 to ensure the continued operation of the MPPT auxiliary source circuit 55. Instead, the auxiliary source voltage is directly transmitted from the second node N2 to the MPPT auxiliary source circuit 55. There is no power loss during this process, thereby saving energy and improving the utilization rate of photovoltaic energy.

[0086] Please continue reading. Figure 13 The voltage feedback circuit 56 includes a second diode. The positive terminal of the second diode D2 is electrically connected to the MPPT auxiliary power supply circuit 55, and the negative terminal of the second diode D2 is electrically connected to the second node N2. The second diode D2 and the MPPT auxiliary power supply circuit 55 can form a loop. The auxiliary power supply voltage output by the MPPT auxiliary power supply circuit 55 is fed back to the second node through the second diode D2, and then fed back to the MPPT auxiliary power supply circuit 55 from the second node.

[0087] Please see Figure 15The maximum power point tracking (MPPT) circuit 500 also includes an auxiliary source feedback circuit 57, which is electrically connected to the MPPT auxiliary source circuit 55. The auxiliary source feedback circuit 57 sends a voltage feedback signal to the MPPT auxiliary source circuit 55 based on the auxiliary source voltage and a preset voltage threshold, so that the MPPT auxiliary source circuit 55 adjusts the auxiliary source voltage based on the voltage feedback signal. For example, when the auxiliary source voltage is greater than the preset voltage threshold, the auxiliary source feedback circuit 57 sends a low-level voltage feedback signal to the MPPT auxiliary source circuit 55. Based on the low-level voltage feedback signal, the MPPT auxiliary source circuit 55 increases the auxiliary source voltage to stabilize it within the normal voltage range. When the auxiliary source voltage is less than or equal to the preset voltage threshold, the auxiliary source feedback circuit 57 sends a high-level voltage feedback signal to the MPPT auxiliary source circuit 55. Based on the high-level voltage feedback signal, the MPPT auxiliary source circuit 55 decreases the auxiliary source voltage to stabilize it within the normal voltage range. Therefore, this embodiment of the application, through the auxiliary source feedback circuit 57, can ensure that the MPPT auxiliary source circuit 55 outputs a reliable and accurate auxiliary source voltage.

[0088] Please combine Figure 13 and Figure 16 The auxiliary power feedback circuit 57 includes the twenty-sixth resistor R26, the twenty-seventh resistor R27, the twenty-eighth resistor R28, the twenty-ninth resistor R29, the thirtieth resistor R30, the twenty-second capacitor C22, the optocoupler U5, the twenty-third capacitor C23, and the second voltage regulator TL2.

[0089] The auxiliary source voltage is sampled by resistors R28 (28th) and R30 (30th) and then applied to the reference terminal R of the second regulator TL2. When the auxiliary source voltage is greater than a preset voltage threshold (e.g., 2.5V), the anode and cathode of the second regulator TL2 are connected, and the primary side of optocoupler U5 enters the conducting state and emits light. The secondary side of optocoupler U5 receives the light emission signal and enters the conducting state, thereby outputting a low-level voltage feedback signal. Based on the low-level voltage feedback signal, power control chip U2 controls flyback power supply circuit 551 to increase the auxiliary source voltage. When the auxiliary source voltage is lower than or equal to the preset voltage threshold (e.g., 2.5V), the anode and cathode of the second regulator TL2 are disconnected, and the primary side of optocoupler U5 enters the off state and does not emit light. The secondary side of optocoupler U5 does not receive the light emission signal and enters the off state, thereby outputting a high-level voltage feedback signal. Based on the high-level voltage feedback signal, power control chip U2 controls flyback power supply circuit 551 to decrease the auxiliary source voltage. The embodiments of this application are based on the auxiliary source feedback circuit 57, which can control the MPPT auxiliary source circuit 55 to output a reliable and accurate auxiliary source voltage.

[0090] To illustrate in detail the working principle of the maximum power point tracking circuit provided in the embodiments of this application, the embodiments of this application are combined with... Figure 17 This will be explained in detail below:

[0091] ①. The photovoltaic voltage (PV+, PV-) is greater than the cell voltage (BAT+, BAT-).

[0092] When the photovoltaic voltage is greater than the battery voltage, the optocoupler U1 enters the working state, pulling down the gate voltage of the first PMOS transistor PQ1, causing the first PMOS transistor PQ1 to enter the conducting state, which in turn pulls down the first voltage of the first node N1. At this time, the BE voltage (the voltage difference between the base voltage and the emitter voltage) of the first NPN transistor NS1 is close to equal to the breakdown voltage of the Zener diode ZD. Therefore, the first NPN transistor NS1 enters the conducting state.

[0093] Both the first NPN transistor NS1 and the first PMOS transistor PQ1 are in the conducting state. At this time, the photovoltaic voltage can be transmitted to the power control chip U2 through the first NPN transistor NS1 and the first PMOS transistor PQ1 at the second node N2, thereby activating the power control chip U2 to enter the working state. Thus, the MPPT auxiliary power circuit 55 has been activated.

[0094] When the MPPT auxiliary power supply circuit 55 enters the working state, the 12V auxiliary power supply voltage output by the flyback power supply circuit 551 is fed back to the second node N2 through the second diode D2, making the emitter voltage of the first NPN transistor NS1 greater than the base voltage. Therefore, the first NPN transistor NS1 does not meet the conduction condition and enters the off state. The photovoltaic voltage cannot be transmitted to the power control chip U2 through the twelfth resistor R12, the first NPN transistor NS1 and the first PMOS transistor PQ1. However, the 12V auxiliary power supply voltage can be transmitted to the power control chip U2 through the second diode D2. Therefore, the power control chip U2 can continue to work. That is, after the MPPT auxiliary power supply circuit 55 is activated and after the path switching operation, it can continue to maintain the working state and does not waste power.

[0095] Simultaneously, the 12V auxiliary source voltage causes the NPN transistor NS0 to enter the conducting state. When the MPPT controller 522 outputs a low level, the optocoupler U0 enters the working state, and the 12V auxiliary source voltage is transmitted to the gate of the first NMOS transistor NQ1 through the optocoupler U0, thereby driving the first NMOS transistor NQ1 to enter the conducting state. When the MPPT controller 522 outputs a high level, the optocoupler U0 does not enter the working state, and the 12V auxiliary source voltage cannot be transmitted to the gate of the first NMOS transistor NQ1 through the optocoupler U0, so the first NMOS transistor NQ1 enters the off state. In this way, the MPPT controller 522 can control the working state of the first NMOS transistor NQ1, thereby causing the buck circuit 51 to complete the buck operation.

[0096] ②. The photovoltaic voltage (PV+, PV-) is less than or equal to the cell voltage (BAT+, BAT-).

[0097] When the photovoltaic voltage is less than or equal to the battery voltage, the optocoupler U1 does not enter the working state, the first NPN transistor NS1 and the first PMOS transistor PQ1 are both in the off state, the photovoltaic voltage cannot be transmitted to the power control chip U2 through the first NPN transistor NS1 and the first PMOS transistor PQ1, and the MPPT auxiliary power circuit 55 cannot be activated.

[0098] Unlike related technologies, the embodiments of this application do not rely on the microcontroller of the power equipment. They can activate the MPPT auxiliary power circuit 55 using their own MPPT auxiliary power trigger circuit 53, thus improving the operational reliability of the MPPT circuit. Furthermore, when the power equipment 100 is in a shutdown or standby state, the Zener diode ZD and the first diode D1 can block the circuit from which the battery charge flows through the body diode of the first NMOS transistor NQ1 to ground, preventing the battery 15 from being completely depleted.

[0099] Understandably, the maximum power point tracking circuit 500 can be applied to various types of power equipment, including UPS equipment or inverter equipment.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A maximum power point tracking circuit, characterized in that, include: The step-down circuit is electrically connected between the photovoltaic module and the battery of the power equipment. The MPPT control circuit is electrically connected to the step-down circuit. The MPPT auxiliary power trigger circuit is electrically connected between the positive terminal of the photovoltaic module and the positive terminal of the battery, and is configured to generate an auxiliary power trigger signal in response to the photovoltaic voltage of the photovoltaic module being greater than the battery voltage of the battery. The auxiliary power start-up circuit is electrically connected to the MPPT auxiliary power trigger circuit and the photovoltaic module, respectively, and is configured to output the photovoltaic voltage of the photovoltaic module in response to the input of the auxiliary power trigger signal; The MPPT auxiliary power circuit, which is electrically connected to the auxiliary power start-up circuit, is configured to enter the working state in response to the input of the photovoltaic voltage.

2. The maximum power point tracking circuit according to claim 1, characterized in that, The MPPT auxiliary source trigger circuit includes: The primary-side circuit of the optocoupler is electrically connected between the positive terminal of the photovoltaic module and the positive terminal of the battery, and is configured to emit an optocoupler signal in response to the photovoltaic voltage of the photovoltaic module being greater than the battery voltage of the battery. The secondary circuit of the optocoupler, coupled to the primary circuit of the optocoupler and electrically connected to the auxiliary power source activation circuit, is configured to generate an auxiliary power source trigger signal in response to the input of the optocoupler signal.

3. The maximum power point tracking circuit according to claim 1, characterized in that, The auxiliary power start-up circuit includes: The first switching circuit includes a first node and a second node. The first switching circuit is electrically connected to the MPPT auxiliary source trigger circuit and is electrically connected to the MPPT auxiliary source circuit at the second node. It is configured to enter the conduction state and pull down the first voltage of the first node in response to the input of the auxiliary source trigger signal. The second switching circuit includes a third node, which is electrically connected to the first switching circuit at the first node and electrically connected to the positive terminal of the photovoltaic module at the third node. It is configured to transmit the photovoltaic voltage to the MPPT auxiliary power circuit via the second node through the first switching circuit that enters the conduction state under the action of the photovoltaic voltage and the first voltage after being pulled down.

4. The maximum power point tracking circuit according to claim 3, characterized in that, The first switching circuit includes a first PMOS transistor, the gate of which is configured to receive the auxiliary source trigger signal, the source of which is electrically connected to the first node, and the drain of which is electrically connected to the second node; or, The first switching circuit includes a first PNP transistor, the base of which is configured to receive the auxiliary source trigger signal, the emitter is electrically connected to the first node, and the collector is electrically connected to the second node.

5. The maximum power point tracking circuit according to claim 3, characterized in that, The second switching circuit includes a Zener diode, a first NPN transistor, and a first diode. The negative terminal of the Zener diode is electrically connected to the base of the first NPN transistor and is configured to receive the photovoltaic voltage. The positive terminal of the Zener diode is electrically connected to the negative terminal of the photovoltaic module. The collector of the first NPN transistor is configured to receive the photovoltaic voltage. The emitter of the first NPN transistor is electrically connected to the first node. The positive terminal of the first diode is electrically connected to the first node, and the negative terminal of the first diode is electrically connected to the base of the first NPN transistor.

6. The maximum power point tracking circuit according to claim 3, characterized in that, It also includes a voltage feedback circuit, which is electrically connected to the MPPT auxiliary power supply circuit and also electrically connected to the second node. It is configured to feed back the auxiliary power supply voltage of the MPPT auxiliary power supply circuit to the first switching circuit, so that the first switching circuit enters the off state and cuts off the power supply circuit from the photovoltaic module to the MPPT auxiliary power supply circuit.

7. The maximum power point tracking circuit according to claim 6, characterized in that, The voltage feedback circuit includes a second diode, the positive terminal of which is electrically connected to the MPPT auxiliary power circuit, and the negative terminal of which is electrically connected to the second node.

8. The maximum power point tracking circuit according to any one of claims 1 to 7, characterized in that, The MPPT control circuit includes: The switch drive circuit is electrically connected to the MPPT auxiliary power circuit and the step-down circuit, respectively. The MPPT controller is electrically connected to the switch drive circuit and is configured to control the switch drive circuit to drive the buck circuit to perform a buck operation.

9. The maximum power point tracking circuit according to claim 8, characterized in that, The switch driving circuit includes: The drive protection circuit, electrically connected to the MPPT auxiliary power supply circuit, is configured to output the auxiliary power supply voltage of the MPPT auxiliary power supply circuit in response to the auxiliary power supply voltage of the MPPT auxiliary power supply circuit being within the normal voltage range, or to stop outputting the auxiliary power supply voltage of the MPPT auxiliary power supply circuit in response to the auxiliary power supply voltage of the MPPT auxiliary power supply circuit deviating from the normal voltage range. The drive control circuit is electrically connected to the drive protection circuit and the MPPT controller, respectively, and is configured to be controlled by the MPPT controller to transmit the auxiliary source voltage to the buck circuit to drive the buck circuit to perform buck operation.

10. The maximum power point tracking circuit according to any one of claims 1 to 7, characterized in that, It also includes an auxiliary source feedback circuit, which is electrically connected to the MPPT auxiliary source circuit and is configured to send a voltage feedback signal to the MPPT auxiliary source circuit based on the auxiliary source voltage and a preset voltage threshold, so that the MPPT auxiliary source circuit adjusts the auxiliary source voltage based on the voltage feedback signal.

11. An electrical device, characterized in that, Includes the maximum power point tracking circuit as described in any one of claims 1 to 10.

12. A new energy system, characterized in that, The device includes a photovoltaic module, a maximum power point tracking circuit as described in any one of claims 1 to 10, and a power device, wherein the maximum power point tracking circuit is electrically connected between the photovoltaic module and the battery of the power device.

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