An MPPT wide-range input and multi-voltage output auxiliary source circuit

Abstract

This invention relates to an MPPT (Multi-Purpose Power Transmission Test) wide-range input and multi-voltage output auxiliary source circuit, comprising an auxiliary source chip U31, input / output power supply circuits, an auxiliary source chip control circuit, an isolation drive circuit, a dual-transistor flyback circuit, a 12V to ±5V conversion circuit, and an 8V to multi-channel voltage conversion circuit. The auxiliary source samples voltages from the input and output. When the voltage rises to a threshold voltage, it triggers the chip's internal logic to output a drive signal. This drive signal is then transmitted through the isolation drive circuit to the primary-side MOSFET of the dual-transistor flyback circuit. The primary-side MOSFET's switching on and off transfers energy from the transformer's primary winding to the secondary winding. After rectification, 12V and 8V voltages are output. These voltages are then output through corresponding flyback or conversion circuits. By drawing power from both the input and output, the auxiliary source ensures output from both sides, increasing its input range and enabling the output of multiple voltages. This greatly expands the application range of MPPTs, and with high efficiency and stability, it can be widely used in various photovoltaic power generation systems.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology for photovoltaic energy, and specifically to an MPPT wide-range input and multi-voltage output auxiliary power source circuit. Background Technology

[0002] Currently, the country is vigorously developing the photovoltaic field. Photovoltaic power generation and energy storage both utilize large-area photovoltaic panels to improve the utilization rate of solar energy. Photovoltaic power generation utilizes the photovoltaic effect, directly converting solar radiation energy into electrical energy. The basic device for light-to-electricity conversion is the solar cell. A solar cell is a device that directly converts solar energy into electrical energy due to the photovoltaic effect. It is a semiconductor photodiode. When sunlight shines on the photodiode, it converts the sunlight into electrical energy, generating current. When many cells are connected in series or parallel, they can form a solar cell array with a relatively large output power. Solar cells are a promising new type of power source with three major advantages: permanence, cleanliness, and flexibility. Solar cells have a long lifespan; as long as the sun exists, solar cells can be used for a long time with a one-time investment. Compared with thermal power generation and nuclear power generation, solar cells do not cause environmental pollution.

[0003] Currently, the efficiency of photovoltaic power generation depends on the materials, structure, and manufacturing process of the cells, as well as environmental factors such as light intensity, spectral distribution, and temperature. With the advancement of technology, new materials have gradually made up for the low efficiency of old materials, but they are still subject to the influence of light intensity and temperature. Therefore, photovoltaic power generation has a dynamic output, and its maximum output power also changes dynamically with the above influences. This led to the development of MPPT (Maximum Power Point Tracking) controllers. MPPT controllers can detect the generation voltage of solar panels in real time and track the highest voltage and current value (VI), so that the photovoltaic array always outputs maximum power. Photovoltaic arrays equipped with MPPT controllers can charge the battery at maximum power output, with a tracking efficiency of up to 99.9% and an overall system power generation efficiency of over 97%, which is about 50% higher than traditional systems.

[0004] Photovoltaic power generation typically consists of a photovoltaic array connected in series and parallel, a DC / DC converter, and an MPPT controller, as shown in the schematic diagram below. Figure 1As shown, the MPPT system mainly includes a DC / DC converter, an MPPT controller, and various communication and interface components. In the photovoltaic power generation field, photovoltaic panels are connected in series and parallel to form a photovoltaic array with high voltage and current. The DC / DC converter regulates the output voltage and current, and finally outputs the energy of the photovoltaic panels to the downstream load. The MPPT controller continuously detects the changes in current and voltage of the photovoltaic array and adjusts the duty cycle of the PWM drive signal of the DC / DC converter accordingly to maintain the maximum power output of the photovoltaic array.

[0005] Because downstream loads are diverse, such as batteries, system buses, and large equipment, the MPPT system needs to have a wide range of output capabilities to meet the voltage and current requirements of various loads. Secondly, the size of the photovoltaic array and its dynamic output throughout the day also require the MPPT system to meet a wide range of input requirements. The MPPT and its system contain various semiconductor devices and control ICs, and their reliable operation requires a variety of voltages for power supply.

[0006] Under these conditions, the auxiliary power source of the MPPT system needs to be able to operate normally and stably under a wide range of input conditions, and needs to output multiple voltages to meet the requirements. Summary of the Invention

[0007] In view of this, a wide-range input and multi-voltage output auxiliary source circuit for MPPT is provided, which is widely applicable, efficient and stable. It can meet the requirement that the auxiliary source has an output when either the input or output side of the MPPT system is powered. The input range of the auxiliary source is greatly increased, and the output voltage types of the auxiliary source are more numerous. It can meet the voltage power supply requirements of various parts inside the MPPT, and can also provide additional output voltage to meet the needs of customers to connect to various control boards.

[0008] An MPPT wide-range input and multi-voltage output auxiliary power source circuit is mainly used in multi-channel photovoltaic cell systems. It includes an auxiliary power source chip U31, input and output power supply circuits, auxiliary power source chip control circuit, isolation drive circuit, dual-transistor flyback circuit, 12V to ±5V circuit, and 8V to multi-channel voltage circuit.

[0009] The input and output power supply circuit includes an input power supply diode and an output power supply diode. The input power supply diode is connected to the MPPT system input, and the output power supply diode is connected to the MPPT system output to draw power accordingly as the auxiliary source bus voltage.

[0010] The auxiliary source chip control circuit includes an auxiliary source chip power supply circuit and a feedback circuit. The auxiliary source chip power supply circuit includes a voltage divider resistor and / or a current limiting resistor, with one end connected to the auxiliary source bus voltage and the other end connected to the power supply pin VCC of the auxiliary source chip U31. The feedback circuit includes an isolation optocoupler circuit. The secondary side of the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31. The anode of the primary side of the isolation optocoupler circuit is connected to a predetermined voltage output, and the cathode is connected to the primary side isolation Zener diode U22.

[0011] The dual-transistor flyback circuit includes an upper MOSFET Q57, a lower MOSFET Q58, and a flyback transformer. The source of the upper MOSFET Q57 and the drain of the lower MOSFET Q58 are respectively connected to the opposite-named terminal and the same-named terminal of the primary side of the flyback transformer. The flyback transformer has a first flyback secondary winding T1-C and a second flyback secondary winding T1-B. The two flyback secondary windings have corresponding output voltages. The second flyback secondary winding T1-B is connected to a 12V to ±5V circuit, and the first flyback secondary winding T1-C is connected to an 8V to multiplex voltage circuit. The anode and cathode of the primary side of the isolation optocoupler circuit are connected in parallel across the two ends of the second flyback secondary winding.

[0012] The isolation drive circuit includes an isolation drive transistor Q144, an isolation drive switch Q11, and an isolation drive transformer T4. The base of the isolation drive transistor Q144 and the gate of the isolation drive switch Q11 are connected to the drive pin GATE of the auxiliary source chip U31. The isolation drive transistor Q144 and the isolation drive switch Q11 are connected in series through the primary winding of the isolation drive transformer T4 and are synchronously turned on and off under the signal drive of the drive pin GATE of the auxiliary source chip U31. The secondary side of the isolation drive transformer T4 has a first drive secondary winding and a second drive secondary winding. The two ends of the first drive secondary winding are connected in parallel to the gate and source of the upper MOSFET Q57, and the two ends of the second drive secondary winding are connected in parallel to the gate and source of the lower MOSFET Q58. The upper MOSFET Q57 and the lower MOSFET Q58 are turned on or off synchronously through the first drive secondary winding and the second drive secondary winding.

[0013] The 12V to ±5V circuit is connected to a DC-DC converter circuit through a rectifier diode D55. The DC-DC converter circuit has a DC-DC converter chip U5. The switch output pin SW of the DC-DC converter chip U5 is connected to a coupling inductor L18. The primary winding L18-A of the coupling inductor L18 outputs 5V, and the secondary winding L18-B of the coupling inductor L18 is reversed to output -5V voltage.

[0014] The 8V to multi-channel voltage circuit includes a conversion transformer and a multi-channel LDO circuit. The conversion transformer has multiple secondary windings, and each secondary winding is connected to an LDO circuit to output the required voltage.

[0015] Furthermore, there are multiple input power-taking diodes, each of which is connected to a corresponding photovoltaic cell system. The output power-taking diodes are connected to the output of the MPPT system. The cathodes of each input or output power-taking diode are connected to one end of fuse F7. The other end of fuse F7 is connected to one end of thermistor RNTC1. The other end of thermistor RNTC1 is connected to the positive terminal of the first electrolytic capacitor C2. The negative terminal of the first electrolytic capacitor C2 is connected to the positive terminal of the second electrolytic capacitor C37. The negative terminal of the second electrolytic capacitor C37 is grounded. The first electrolytic capacitor C2 and the second electrolytic capacitor C37 are both connected in parallel with at least one resistor for voltage division. The auxiliary power supply bus voltage is obtained between the positive terminal of the first electrolytic capacitor C2 and ground.

[0016] Furthermore, the power supply pin VCC of the auxiliary source chip U31 is further connected to the 12V output of the auxiliary source itself. A diode D3 and a fifth current-limiting resistor R674 are connected in series between the power supply pin VCC and the 12V output of the auxiliary source. A third electrolytic capacitor and a filter capacitor C47 are connected in parallel between the fifth current-limiting resistor R674 and the power supply pin VCC. The other end of the third electrolytic capacitor and the filter capacitor C47 connected in parallel is grounded.

[0017] Furthermore, the auxiliary source chip control circuit also includes an input undervoltage circuit and an output overvoltage circuit. The input undervoltage circuit includes a sampling resistor, one end of which is connected to the auxiliary source bus voltage, and the other end is connected to the undervoltage protection pin BO of the auxiliary source chip U31. An undervoltage regulator unit is also connected between the sampling resistor and the undervoltage protection pin BO of the auxiliary source chip U31. The undervoltage regulator unit includes a parallel voltage regulator resistor R85, an undervoltage regulator capacitor C212, and an undervoltage regulator diode Z5. One end of the undervoltage regulator unit is connected to the sampling resistor and the undervoltage protection pin BO. One end is grounded; the output overvoltage circuit is connected to the detection pin DEMAG of the auxiliary source chip U31; the output overvoltage circuit includes two overvoltage protection resistors R297 and R282 connected in series, the midpoint of the two overvoltage protection resistors R297 and R282 is connected to the detection pin DEMAG of the auxiliary source chip U31, one of the overvoltage protection resistors R282 is connected in parallel with an overvoltage protection capacitor C383 between the midpoint and the ground terminal; one input end of the other overvoltage protection resistor R297 is connected to the auxiliary source bus voltage or the auxiliary source output.

[0018] Furthermore, the collector of the secondary-side transistor OT1-A in the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31 through a series resistor R88. A capacitor C214 is connected in parallel between the series resistor R88 and the emitter of the collector of the secondary-side transistor OT1-A, and the capacitor C214 and the emitter are grounded together. The anode of the primary-side LED OT1-B in the isolation optocoupler circuit is connected to the 12V output of the auxiliary source itself after a series and parallel resistor. The cathode of the primary-side LED OT1-B is connected to the primary-side isolation Zener diode U22. The output pin of the primary-side isolation Zener diode U22 is connected to the same-name terminal of the second flyback secondary winding T1-B. Resistors are connected in series and parallel between the pins of the primary-side isolation Zener diode U22 for current shunting or voltage division.

[0019] Furthermore, the 12V to ±5V circuit is connected to the input pin VIN of the DC-DC converter chip U5 through a rectifier diode D55. A fourth electrolytic capacitor C35 and a capacitor C17 are connected in parallel between the same-name and opposite-name terminals of the second flyback secondary winding T1-B. The same-name terminal of the second flyback secondary winding T1-B is grounded together with the ground pin of the DC-DC converter chip U5. The inductor secondary winding L18-B is connected to the -5V voltage output terminal L_-5V through a reverse tenth diode D10. The midpoint between the anode of the tenth diode D10 and the -5V voltage output terminal L_-5V is grounded through a fifth electrolytic capacitor C140, and the positive terminal of the fifth electrolytic capacitor C140 is grounded.

[0020] Furthermore, the emitter of the isolation driver transistor Q144 is connected to the opposite-named terminal of the primary side of the isolation driver transformer T4, and the collector of the isolation driver transistor Q144 is connected to the first auxiliary source output terminal VAUX1. The first auxiliary source output terminal VAUX1 is connected to the power supply pin VCC of the auxiliary source chip U31 or to the 12V output terminal of the step-down auxiliary source itself. The collector of the isolation driver transistor Q144 is connected to the same-named terminal of the primary side of the isolation driver transformer T4 through the ninth Zener diode Z9 and the first zero-one diode D101 connected in reverse. The drain of the isolation driver switch Q11 is connected to the opposite-named terminal of the primary side of the isolation driver transformer T4, and the source of the isolation driver switch Q11 is connected to the same-named terminal of the primary side of the isolation driver transformer T4 through a first zero-two diode D102. The anode of the first zero-two diode D102 is connected to the source of the isolation driver switch Q11 and grounded.

[0021] Specifically, the source of the upper MOSFET Q57 is connected to the opposite terminal of the primary winding T1-A of the flyback transformer, the drain of the upper MOSFET Q57 is connected to the auxiliary source bus voltage, and the drain of the upper MOSFET Q57 is connected to the same terminal of the primary winding T1-A of the flyback transformer through a reverse thirteenth diode D13, with the anode of the thirteenth diode D13 connected to the same terminal of the primary winding T1-A; the drain of the lower MOSFET Q58 is connected to the same terminal of the primary winding T1-A of the flyback transformer, and the lower MOSFET Q58... The source of MOSFET Q58 is connected to the same-name terminal of the second driving secondary winding and then grounded through at least one shunt resistor. The opposite-name terminal of the primary winding T1-A is connected to one end of the shunt resistor that is grounded through a reverse seventy-second diode D72. The cathode of the seventy-second diode D72 is connected to the opposite-name terminal of the primary winding T1-A. The same-name terminal of the second driving secondary winding and the source of the lower MOSFET Q58 are connected to the detection pin CS of the auxiliary source chip U31 through a resistor R239.

[0022] Specifically, the 8V to multi-channel voltage circuit also includes an 8V to EX_5V circuit; the 8V to EX_5V circuit includes a first LDO circuit, the first LDO circuit includes a fourteenth LDO chip U14, the input pin IN of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a twenty-third capacitor C23 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a forty-second capacitor C42 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected to the EX_5V output terminal of the auxiliary source.

[0023] Furthermore, the 8V output of the first flyback secondary winding T1-C is connected to the power supply pin VDD and enable pins ENA and ENB of a secondary flyback circuit chip U1, respectively. The input pin of the secondary flyback circuit chip U1 is connected to a control signal output terminal of the MPPT controller. The 8V to multiplex voltage circuit has multiple conversion transformers, each conversion transformer including a primary winding and at least one secondary winding. The two ends of the secondary winding of each conversion transformer are connected in parallel to the input terminal and ground terminal of the corresponding LDO circuit, respectively. A capacitor is connected in parallel between the input terminal and ground terminal of each LDO circuit, and another capacitor is connected in parallel between the output terminal and ground terminal. The opposite-named terminal of the group is connected to the input terminal of the corresponding LDO circuit through a forward diode; the same-named terminal of the primary winding of each conversion transformer is connected to the output pin of the secondary flyback circuit chip U1 through a transformer switching transistor; the gate of each transformer switching transistor is connected to the output pin of the secondary flyback circuit chip U1 through a resistor, the drain is connected to the same-named terminal of the primary winding of the corresponding conversion transformer, and the source is grounded; a capacitor is connected in parallel between the drain and source of each transformer switching transistor and then grounded; a filter unit is connected in parallel between the gate and source of each transformer switching transistor and then grounded, the filter unit including a capacitor and a resistor connected in parallel; the opposite-named terminal of the primary winding of each conversion transformer is connected to the 8V output of the first flyback secondary winding T1-C.

[0024] In the aforementioned MPPT wide-range input and multi-voltage output auxiliary source circuit, the input and output power-taking diodes allow the auxiliary source bus voltage to be obtained from either the MPPT input or output side when either is energized, ensuring that all auxiliary sources have output. This significantly increases the auxiliary source input range. The flyback transformer in the dual-transistor flyback circuit corresponds to multiple flyback secondary windings to provide different voltages, such as 12V output, 12V to ±5V circuit output ±5V, 8V output, and 8V to multiple voltage circuits, such as EX_5V, CAN1_5V, CAN2_5V, 485_1_5V, 485_2_5V, and DIDO_5V. This satisfies the voltage power supply requirements of various parts within the MPPT and provides additional output voltage to meet the needs of multiple control boards, greatly expanding the application range of the MPPT and exhibiting high efficiency and stability. Therefore, the aforementioned circuit has broad application prospects. Attached Figure Description

[0025] Figure 1 This is the schematic diagram of the MPPT controller in a photovoltaic power generation system.

[0026] Figure 2 This is a schematic diagram of the input and output power supply circuit in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention.

[0027] Figure 3 This is a schematic diagram of the auxiliary source chip control circuit in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention.

[0028] Figure 4 This is the primary-side circuit diagram of the isolation drive circuit and the dual-transistor flyback circuit in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention.

[0029] Figure 5 This is a circuit diagram of the secondary side T1-B of the dual-transistor flyback circuit in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention, as well as the schematic diagram of the 12V to ±5V circuit.

[0030] Figure 6 This is a schematic diagram of the 8V to EX_5V circuit in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention.

[0031] Figure 7 This is a schematic diagram of the 8V to CAN1_5V, CAN2_5V, 485_1_5V, 485_2_5V, and DIDO_5V circuits in the MPPT wide-range input and multi-voltage output auxiliary source circuit of this invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 2 to 7 This illustration shows the various structures of an MPPT wide-range input and multi-voltage output auxiliary source circuit provided by an embodiment of the present invention. It is mainly used in multi-channel photovoltaic cell systems and includes an auxiliary source chip U31, an input and output power supply circuit, an auxiliary source chip control circuit, an isolation drive circuit, a dual-transistor flyback circuit, a 12V to ±5V circuit, and an 8V to multi-channel voltage circuit.

[0034] In one specific embodiment, the photovoltaic cell system has a photovoltaic cell array, i.e., multiple rows of photovoltaic panels. MPPT, or Maximum Power Point Tracking, works as follows: the input side of the MPPT system is typically connected to a series of photovoltaic panels. The photovoltaic panels convert solar energy into electrical energy through the photovoltaic effect, outputting voltage and current to the MPPT system. The MPPT system monitors the output voltage U and output current I of the photovoltaic panels in real time. Due to environmental changes throughout the day, the output voltage U and output current I of the photovoltaic panels are constantly changing, so their power P = U * I also changes dynamically. However, there is a maximum P at any given moment. Therefore, the MPPT system typically uses algorithms for real-time tracking. There are many types of algorithms available today, but the most commonly used are the perturbation and observation method and the conductance increment method. This embodiment of the invention uses the first perturbation and observation method, which involves periodically applying positive or negative increments to the output voltage of the photovoltaic panels by adjusting the MPPT controller and observing the changes in system power to determine the next voltage adjustment direction. If the power increases, the increment in the same direction is applied; conversely, the increment in the opposite direction is applied until the output power reaches its maximum value. This algorithm is simple, direct, and easy to implement. However, because it is based on a fixed step size perturbation, it may cause oscillations near the maximum power point. Therefore, in practical applications, this invention also incorporates a variable step size strategy to improve tracking accuracy and stability.

[0035] MPPT systems typically need to meet a wide range of input and output voltage requirements. Furthermore, due to the complexity of the internal system, many parts require different operating voltages. Therefore, an auxiliary source solution with a wide range of input and multiple voltage outputs is needed for MPPT.

[0036] In this embodiment, the input / output power supply circuit includes an input power supply diode and an output power supply diode. The input power supply diode is connected to the input, and the output power supply diode is connected to the output to draw power accordingly, serving as the auxiliary source bus voltage. The input power supply diode draws power from the input of the MPPT system, or from the various connection points of the photovoltaic array to the MPPT controller. The output power supply diode draws power from the output side of the MPPT system, which is the actual output voltage to the battery load or bus. Therefore, the auxiliary source circuit samples the voltage from the input and output to ensure that the MPPT controller can maintain a normal and stable auxiliary source output at both the pre- and post-connection stages.

[0037] The auxiliary source chip control circuit includes an auxiliary source chip power supply circuit and a feedback circuit. The auxiliary source chip power supply circuit includes voltage divider resistors and / or current limiting resistors, with one end connected to the auxiliary source bus voltage and the other end connected to the power supply pin VCC of the auxiliary source chip U31. The feedback circuit includes an isolation optocoupler circuit. The secondary side of the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31. The anode of the primary side of the isolation optocoupler circuit is connected to a predetermined voltage output, and the cathode is connected to the primary side isolation Zener diode U22. The primary side isolation Zener diode U22 cooperates with the primary and secondary sides of the isolation optocoupler circuit to perform closed-loop control, thereby stabilizing the 12V voltage output.

[0038] The dual-transistor flyback circuit includes an upper MOSFET Q57, a lower MOSFET Q58, and a flyback transformer. The source of the upper MOSFET Q57 and the drain of the lower MOSFET Q58 are respectively connected to the opposite-named terminal and the same-named terminal of the primary side of the flyback transformer. Specifically, as shown... Figure 4 As shown, the primary winding T1-A of the flyback transformer is divided into two sections: a first primary winding and a second primary winding. The first primary winding has a terminal 10 with the same name, and the second primary winding has a terminal 11 with the same name. The two primary windings share a terminal 12 with a different name. The source of the upper MOSFET Q57 is connected to the common terminal 12 of the primary winding T1-A of the flyback transformer, and the drain of the lower MOSFET Q58 is connected to the terminal 10 of the first primary winding of the primary winding T1-A of the flyback transformer. The flyback transformer has a first flyback secondary winding T1-C and a second flyback secondary winding T1-B. The two flyback secondary windings each have a corresponding output voltage. The second flyback secondary winding T1-B is connected to a 12V to ±5V circuit, and the first flyback secondary winding T1-C is connected to an 8V to multi-channel voltage circuit. The anode and cathode of the primary side of the isolation optocoupler circuit are connected in parallel at both ends of the second flyback secondary winding.

[0039] The isolation drive circuit includes an isolation drive transistor Q144, an isolation drive switch Q11, and an isolation drive transformer T4. The base of the isolation drive transistor Q144 and the gate of the isolation drive switch Q11 are connected to the drive pin GATE of the auxiliary source chip U31. The isolation drive transistor Q144 and the isolation drive switch Q11 are connected in series through the primary winding of the isolation drive transformer T4, and are synchronously turned on and off under the signal drive of the drive pin GATE of the auxiliary source chip U31. The secondary side of the isolation drive transformer T4 has a first drive secondary winding and a second drive secondary winding. The two ends of the first drive secondary winding are connected in parallel to the gate and source of the upper MOSFET Q57, and the two ends of the second drive secondary winding are connected in parallel to the gate and source of the lower MOSFET Q58. The first drive secondary winding and the second drive secondary winding synchronously drive the upper MOSFET Q57 and the lower MOSFET Q58 to turn on or off. During the isolation drive process, when the VCC voltage of the auxiliary source chip U31 rises to the threshold voltage, the internal logic of the auxiliary source chip U31 is triggered to output a drive signal, that is, the drive signal is output by the drive pin GATE. The drive signal passes through the isolation drive circuit and is transmitted to the upper and lower MOSFETs on the primary side of the dual-transistor flyback circuit. The conduction and turn-off of the upper and lower MOSFETs on the primary side transfer the energy of the transformer primary winding to the secondary winding. The secondary winding outputs 12V and 8V voltages through the rectifier diodes.

[0040] The 12V to ±5V circuit is connected to a DC-DC converter circuit via a rectifier diode D55. This DC-DC converter circuit has a DC-DC converter chip U5. The switch output pin SW of the DC-DC converter chip U5 is connected to a coupling inductor L18. The primary winding L18-A of the coupling inductor L18 outputs 5V, and the secondary winding L18-B of the coupling inductor L18 is reverse-connected to output -5V. Therefore, the second flyback secondary winding T1-B is connected to the primary side of the isolation Zener diode U22 and the primary side of the isolation optocoupler circuit. After providing a stable 12V voltage, the 12V voltage, after passing through the DC-DC converter, outputs 5V to meet the power supply requirements of other ICs inside the MPPT. Simultaneously, the -5V voltage output through the coupling inductor meets the negative voltage turn-off requirement of the main power MOSFET inside the MPPT.

[0041] The 8V to multi-channel voltage conversion circuit includes a conversion transformer and multiple LDO circuits. The conversion transformer has multiple secondary windings, and each secondary winding is connected to an LDO circuit to output the required voltage. Specifically, the first flyback secondary winding T1-C outputs 8V. This 8V voltage is then passed through an LDO circuit to output EX_5V to meet customer power supply requirements. Simultaneously, the 8V voltage is passed through the secondary flyback circuit and each LDO circuit to output CAN1_5V, CAN2_5V, 485_1_5V, 485_2_5V, and DIDO_5V respectively to meet various communication voltage requirements.

[0042] Specifically, such as Figure 2 As shown, there are multiple input power-taking diodes. The example in the figure shows four input power-taking channels, with four input power-taking diodes D11, D60, D53, and D62 connected to the input terminals V_PV1+, V_PV2+, V_PV3+, and V_PV4+ respectively, and one output power-taking channel. Each input power-taking diode is connected to a corresponding photovoltaic cell system, and the output power-taking diodes are connected to the output of the MPPT system. The example in the figure shows output power-taking diode D118 connected to the output terminal VOUT+. The cathodes of each input or output diode are connected to one end of fuse F7. The other end of fuse F7 is connected to one end of thermistor RNTC1. The other end of thermistor RNTC1 is connected to the positive terminal of the first electrolytic capacitor C2. The negative terminal of the first electrolytic capacitor C2 is connected to the positive terminal of the second electrolytic capacitor C37. The negative terminal of the second electrolytic capacitor C37 is grounded. At least one resistor is connected in parallel with both the first electrolytic capacitor C2 and the second electrolytic capacitor C37 to divide the voltage. The example shown in the figure illustrates three resistors connected in parallel across the first electrolytic capacitor C2 and the second electrolytic capacitor C37. The auxiliary power supply bus voltage is obtained between the positive terminal of the first electrolytic capacitor C2 and ground.

[0043] Specifically, such as Figure 3As shown, the auxiliary power supply circuit of the auxiliary source chip uses multiple voltage divider resistors and / or current limiting resistors connected in a series-parallel hybrid connection. The example shown has ten resistors, with five pairs of parallel resistors connected in series. Specifically, resistors R116 and R103 are connected in parallel, resistors R119 and R104 are connected in parallel, resistors R120 and R105 are connected in parallel, resistors R125 and R114 are connected in parallel, and resistors R176 and R115 are connected in parallel. These series and parallel resistors are connected to the power supply pin VCC of the auxiliary source chip U31. Two capacitors are connected in parallel between the power supply pin VCC and ground: a third electrolytic capacitor C215 and a filter capacitor C47, to ensure sufficient startup current for the auxiliary source chip U31 under a wide input range. Furthermore, the power supply pin VCC of the auxiliary source chip U31 is further connected to the auxiliary source's own 12V output. That is, when the auxiliary source has its own output, it can feed back to the auxiliary source chip U31. This ensures that once the auxiliary source output is normal, it can take over the power supply pin VCC voltage, reducing the power consumption of the system. Specifically, a diode D3 and a fifth current-limiting resistor R674 are connected in series between the power supply pin VCC and the 12V output terminal AUX1_12V of the auxiliary source. The positive terminal of the third electrolytic capacitor C215 and the first terminal of the filter capacitor C47 are respectively connected to the node between the power supply pin VCC and the fifth current-limiting resistor R674. The cathode of the third electrolytic capacitor C215 and the second terminal of the filter capacitor C47, which are connected in parallel, are grounded. Additionally, as... Figure 3 As shown, the power supply pin VCC is also connected to the first auxiliary source output terminal VAUX1 of the auxiliary source to supply power to the collector of the isolated drive transistor Q144.

[0044] Furthermore, the auxiliary source chip control circuit also includes an input undervoltage circuit and an output overvoltage circuit. The input undervoltage circuit includes a sampling resistor, one end of which is connected to the auxiliary source bus voltage, and the other end is connected to the undervoltage protection pin BO of the auxiliary source chip U31. Specifically, as shown... Figure 3 As shown, there are multiple sampling resistors, with the example shown being five sampling resistors R181, R177, R161, R87, and R93 connected in series. An undervoltage regulator unit is also connected between the sampling resistors and the undervoltage protection pin BO of the auxiliary source chip U31. This undervoltage regulator unit includes a parallel-connected voltage regulator resistor R85, an undervoltage regulator capacitor C212, and an undervoltage regulator diode Z5. One end of the undervoltage regulator unit is connected to the sampling resistors and the undervoltage protection pin BO, and the other end is grounded. Specifically, the output terminal of the undervoltage regulator diode Z5 is connected to the fifth sampling resistor R93 and also to the undervoltage protection pin BO of the auxiliary source chip U31.

[0045] like Figure 3As shown, the output overvoltage circuit is connected to the detection pin DEMAG of the auxiliary source chip U31. The output overvoltage circuit includes two overvoltage protection resistors R297 and R282 connected in series. The midpoint of the two overvoltage protection resistors R297 and R282 is connected to the detection pin DEMAG of the auxiliary source chip U31. One overvoltage protection resistor R282 is connected in parallel with an overvoltage protection capacitor C383 between the midpoint and the ground terminal. One input terminal of the other overvoltage protection resistor R297 is connected to the auxiliary source bus voltage or the auxiliary source output. For example, as shown, the front-end overvoltage protection resistor R297 is first connected to the auxiliary source output, such as the 12V output terminal AUX1_12V. When the detection pin DEMAG detects that the voltage at the voltage divider point is too high than the threshold, it sends a signal to the auxiliary source chip U31 for corresponding adjustment and control. The drive pin GATE of the auxiliary source chip U31 is connected to the base of the isolation drive transistor Q144 and the gate of the isolation drive switch Q11 in the isolation drive circuit through a drive resistor R102.

[0046] Furthermore, the collector of the secondary-side transistor OT1-A in the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31 through a series resistor R88. A capacitor C214 is connected in parallel between the series resistor R88 and the emitter of the collector of the secondary-side transistor OT1-A, and the capacitor C214 and the emitter are grounded together. The anode of the primary-side LED OT1-B in the isolation optocoupler circuit is connected to the 12V output of the auxiliary source itself after a series-parallel resistor, serving as the 12V output terminal of the entire auxiliary source. The cathode of the primary-side LED OT1-B is connected to the primary-side isolation Zener diode U22, and the output pin 2 of the primary-side isolation Zener diode U22 is connected to the same-name terminal of the second flyback secondary winding T1-B; the input pin 3 of the primary-side isolation Zener diode U22 is connected to the cathode of the primary-side LED OT1-B, and resistors are connected in series and parallel between the pins of the primary-side isolation Zener diode U22 for current shunting or voltage division. Specifically, resistors R88 and R790 are connected in parallel between the adjustment pin 1 and output pin 2 of the primary-side isolation Zener diode U22, serving to limit current, divide voltage, and shunt current. Resistor R790 can be replaced by a variable resistor or a resistor network, thereby adjusting the output voltage by changing the value of the external resistor connected to adjustment pin 1. The node between the input pin 3 of the primary-side isolation Zener diode U22 and the cathode of the primary-side LED OT1-B is further connected to the intermediate voltage divider point of the two series resistors R790 and R22. A capacitor C25 and a resistor R69 are connected in series between this node and the voltage divider point. The primary-side LED OT1-B and its series resistor R67 are connected in parallel with a resistor R76. One end of resistor R76 is connected to the node between the input pin 3 of the isolation Zener diode U22 and the cathode of the primary-side LED OT1-B, and the other end is connected to the auxiliary 12V output. The primary-side LED OT1-B and the primary-side isolation Zener diode U22 of the isolation optocoupler circuit are connected in series and then in parallel between the same-name and opposite-name terminals of the second flyback secondary winding T1-B. The isolation optocoupler circuit provides timely feedback on the stability of the 12V output. If the output is higher or lower than 12V, it will be directly fed back to the auxiliary source chip U31, which then provides a corresponding drive signal, such as adjusting the idle ratio via a PWM signal to quickly respond to and regulate the voltage output, thereby efficiently and stably outputting the required voltage.

[0047] like Figure 5 and 6As shown, further, the 12V to ±5V circuit is connected to the input pin VIN of the DC-DC converter chip U5 via a rectifier diode D55. The diagram shows the opposite-named terminal of the second flyback secondary winding T1-B connected to the rectifier diode D55, and then connected to the input pin VIN of the DC-DC converter chip U5 via a sixth current-limiting resistor R63. A filter circuit is further connected in parallel across the rectifier diode D55. This filter circuit includes two resistors R163 and R351 connected in parallel and a capacitor C46. The two resistors R163 and R351 are connected in parallel and then in series with the capacitor C46. A fourth electrolytic capacitor C35 and a capacitor C17 are connected in parallel between the same-named and opposite-named terminals of the second flyback secondary winding T1-B; the positive terminal of the fourth electrolytic capacitor C35 is connected to the auxiliary 12V output, for example, as shown in the diagram. Figure 5 The auxiliary source's 12V output terminal is AUX1_12V. The same-named terminal of the second flyback secondary winding T1-B is grounded together with the ground pin of the DC-DC converter chip U5; the inductor secondary winding L18-B is connected to the -5V voltage output terminal L_-5V through a reverse tenth diode D10; the midpoint between the anode of the tenth diode D10 and the -5V voltage output terminal L_-5V is grounded through a fifth electrolytic capacitor C140, with the positive terminal of the fifth electrolytic capacitor C140 connected to ground. The switching output pin SW of the DC-DC converter chip U5 is connected to a coupling inductor L18, and the primary winding L18-A of the coupling inductor L18 is connected in parallel with an output capacitor C29 to provide a stable +5V output voltage, which serves as the +5V output terminal 5VP of the auxiliary source. A capacitor C27 and a resistor R61 are connected between the switch output pin SW and the boot pin BST of the DC-DC converter chip U5 to provide a suitable operating voltage for the high-side drive circuit inside the DC-DC converter chip U5, ensuring that the high-side driver can work normally, thereby realizing effective control of power conversion and other functions. The enable pin EN of the DC-DC converter chip U5 is obtained by voltage division between resistor R30 and another resistor R31. Resistor R30 is connected to the aforementioned 12V output. The feedback pin FB of the DC-DC converter chip U5 is connected in series with resistor R62 and then connected to the series voltage divider point of resistors R32 and R33. Resistor R32 and a capacitor R32 are connected in parallel between this series voltage divider point and the +5V output terminal 5VP. Resistor R33 and another resistor R58 are connected in parallel between this series voltage divider point and the ground terminal. Resistor R31 is grounded, and capacitors C17 and C29 are also grounded.

[0048] like Figure 4As shown, further, the emitter of the isolation driver transistor Q144 is connected to the opposite-named terminal of the primary side of the isolation driver transformer T4, and the collector of the isolation driver transistor Q144 is connected to the first auxiliary source output terminal VAUX1. The first auxiliary source output terminal VAUX1 is connected to the power supply pin VCC of the auxiliary source chip U31 or to the 12V output terminal of the step-down auxiliary source itself. In the initial state, the first auxiliary source output terminal VAUX1 can be connected to the step-down auxiliary source bus voltage, that is, power is first drawn from DC+. When the auxiliary source can output 12V voltage after it is running, the first auxiliary source output terminal VAUX1 can be powered by the auxiliary source itself to cooperate with the conduction or cutoff of the isolation driver transistor Q144. The collector of the isolation drive transistor Q144 is connected to the same-name terminal of the primary side of the isolation drive transformer T4 through the ninth Zener diode Z9 and the first zero-one diode D101 connected in reverse. The drain of the isolation drive switch Q11 is connected to the opposite-name terminal of the primary side of the isolation drive transformer T4. The source of the isolation drive switch Q11 is connected to the same-name terminal of the primary side of the isolation drive transformer T4 through a first zero-two diode D102. The anode of the first zero-two diode D102 is connected to the source of the isolation drive switch Q11 and grounded. Additionally, a diode D100 is connected in parallel between the emitter and base of the isolation drive transistor Q144. The anode of diode D100 is connected to the emitter of the isolation drive transistor Q144 and the opposite-name terminal of the primary side of the isolation drive transformer T4. A resistor R187 is connected in parallel between the source and gate of the isolation drive switch Q11. The source of the isolation drive switch Q11 and the resistor R187 are connected in parallel and then grounded. Diode D100 and resistor R187 protect the isolation drive transistor Q144 and the isolation drive switch Q11, respectively. On the secondary side of the isolation drive transformer T4, the opposite-named terminal of the first drive secondary winding is connected to the gate of the upper MOSFET Q57 via a resistor R188. A freewheeling diode D7 is connected in parallel across the two ends of resistor R188. The freewheeling diode D7 is connected in series with a current-limiting resistor R52 and then in parallel with resistor R188. The opposite-named terminal of the second drive secondary winding is connected to the gate of the lower MOSFET Q58 via a resistor R335. Another freewheeling diode D34 is connected in parallel across the two ends of resistor R335. The freewheeling diode D34 is connected in series with another current-limiting resistor R66 and then in parallel with resistor R335.

[0049] like Figure 4As shown, specifically, the source of the upper MOSFET Q57 is connected to the opposite terminal of the primary winding T1-A of the flyback transformer, the drain of the upper MOSFET Q57 is connected to the auxiliary source bus voltage, and the drain of the upper MOSFET Q57 is connected to the same terminal of the primary winding T1-A of the flyback transformer through a reverse thirteenth diode D13. The anode of the thirteenth diode D13 is connected to the same terminal of the primary winding T1-A. The drain of the lower MOSFET Q58 is connected to the same terminal of the primary winding T1-A of the flyback transformer, and the source of the lower MOSFET Q58 is connected to the same terminal of the second drive secondary winding and then grounded through at least one shunt resistor. The figure shows two shunt resistors R281 and R672 connected in parallel and then grounded. The opposite-named terminal of the primary winding T1-A is connected to one end of the shunt resistor that is grounded via a reverse 72nd diode D72. The cathode of the 72nd diode D72 is connected to the opposite-named terminal of the primary winding T1-A. The same-named terminal of the second driving secondary winding and the source of the lower MOSFET Q58 are connected to the detection pin CS of the auxiliary source chip U31 via a resistor R239. A capacitor C91 is connected in parallel between the drain of the upper MOSFET Q57 and the source of the lower MOSFET Q58. The first end of the capacitor C91 is connected to the drain of the upper MOSFET Q57 or to the auxiliary source bus voltage. The second end of the capacitor C91 is connected in parallel with two shunt resistors R281 and R672 and then grounded.

[0050] The opposite-named terminal of the first flyback secondary winding T1-C is rectified by another rectifier diode D8 to output an 8V voltage. The first flyback secondary winding T1-C can directly output an 8V voltage after rectification, or it can be further connected to various LDO circuits to output corresponding voltages. The same-named terminal of the first flyback secondary winding T1-C is grounded. A sixth electrolytic capacitor C59 is connected in parallel between the opposite-named terminal and the same-named terminal of the first flyback secondary winding T1-C. The positive terminal of the sixth electrolytic capacitor C59 is connected to the opposite-named terminal of the first flyback secondary winding T1-C, or, when rectification is involved, to the cathode of the rectifier diode. The negative terminal of the sixth electrolytic capacitor C59 is grounded. Another filter circuit is further connected in parallel across the rectifier diode D8. This filter circuit includes two resistors R164 and R165 connected in parallel and a capacitor C61 connected in series. The two resistors R164 and R165 are connected in parallel and then in series with the capacitor C61.

[0051] Specifically, such as Figure 6As shown, the 8V to multi-channel voltage circuit also includes an 8V to EX_5V circuit; the 8V to EX_5V circuit includes a first LDO circuit, the first LDO circuit includes a fourteenth LDO chip U14, the input pin IN of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a twenty-third capacitor C23 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a forty-second capacitor C42 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected to the EX_5V output terminal of the auxiliary source.

[0052] Furthermore, such as Figure 7 As shown, the 8V output of the first flyback secondary winding T1-C is connected to the power supply pin VDD and two enable pins ENA and ENB of a secondary flyback circuit chip U1. The input pin of the secondary flyback circuit chip U1 is connected to a control signal output terminal of the MPPT controller. The 8V to multiplex voltage circuit has multiple conversion transformers. Each conversion transformer includes a primary winding and at least one secondary winding. The two ends of the secondary winding of each conversion transformer are connected in parallel to the input terminal and ground terminal of the corresponding LDO circuit. A capacitor is connected in parallel between the input terminal and ground terminal of each LDO circuit, and another capacitor is connected in parallel between the output terminal and ground terminal. The opposite-named terminal of the secondary winding of each conversion transformer is connected to the input terminal of the corresponding LDO circuit through a forward diode. The same-named terminal of the primary winding of each conversion transformer is connected to the output pin of the secondary flyback circuit chip U1 through a transformer switch. Corresponding to the two enable pins ENA and ENB, the secondary flyback circuit chip U1 has two output pins OUTA and OUTB. The gate of each transformer switching transistor is connected to the output pin of the secondary flyback circuit chip U1 through a resistor, the drain is connected to the same-name terminal of the primary winding of the corresponding conversion transformer, and the source is grounded. A capacitor is connected in parallel between the drain and source of each transformer switching transistor and then grounded. A filter unit is connected in parallel between the gate and source of each transformer switching transistor and then grounded. The filter unit includes a capacitor and a resistor connected in parallel. The opposite-name terminal of the primary winding of each conversion transformer is connected to the 8V output of the first flyback secondary winding T1-C.

[0053] by Figure 7Taking the CAN1_5V output circuit as an example, this circuit has a primary winding T5-A of a conversion transformer, a secondary winding T5-B of a first conversion transformer, and a secondary winding T5-C of a second conversion transformer. The corresponding terminal of the primary winding T5-A is connected to an output pin OUTA of the secondary flyback circuit chip U1 through a transformer switch Q5, a third filter circuit, and a seventh current-limiting resistor R49. A capacitor C53 is connected in parallel between the drain and source of the transformer switch Q5 and then grounded. The third filter circuit is connected in parallel between the gate and source of the transformer switch Q5 and then grounded. The third filter circuit includes a fifty-second filter capacitor and a forty-seventh resistor R47. The opposite-name terminal of the primary winding T5-A of the conversion transformer is connected to the 8V output of the aforementioned first flyback secondary winding T1-C. An eighth electrolytic capacitor C384 is connected in parallel before the 8V voltage connected to the opposite-name terminal of the primary winding T5-A. The positive terminal of the eighth electrolytic capacitor C384 is connected to the opposite-name terminal of the primary winding T5-A, and the negative terminal is grounded. The two secondary windings T5-C and T5-B of the conversion transformer are respectively connected to one LDO circuit, designated as the fifth LDO circuit and the sixth LDO circuit. The fifth LDO circuit has a fifth LDO chip U35, and the sixth LDO circuit has a sixth LDO chip U6. Specifically, the opposite-name terminal of the secondary winding T5-C of the second conversion transformer is connected to the input pin IN of the fifth LDO chip U35 through the third rectifier diode D32. Two capacitors C51 and C24 are connected in parallel between the input pin IN of the fifth LDO chip U35 and the ground terminal GND, and another capacitor C12 is connected in parallel between the output pin OUT and the ground terminal GND. The same-name terminal of the secondary winding T5-C of the second conversion transformer, and the other ends of each capacitor C12, C51, and C24 are grounded or connected to the ground terminal GND of the fifth LDO chip U35, respectively. The connection structure between the secondary winding T5-B of the first conversion transformer and the sixth LDO chip U6 in the sixth LDO circuit is basically the same as the connection structure between the secondary winding T5-C of the second conversion transformer and the fifth LDO chip U35 in the fifth LDO circuit, and will not be described again here. The output pin OUT of the sixth LDO chip U6 is filtered by capacitor C66 and outputs another voltage required for communication, for example, as the output pin CAN2_5V. The connection methods of the primary and secondary sides of the other conversion transformers and the LDO circuit are basically the same as the aforementioned connection structure, and they output different voltages respectively, namely the first 485 communication voltage output terminal 485_1_5V, the second 485 communication voltage output terminal 485_2_5V, and the digital input / output voltage terminal DIDO_5V. Figure 7The primary winding T13-C of the transfer transformer at the bottom also corresponds to the secondary windings T13-B and T13-A of the two conversion transformers. The secondary winding T13-A of the conversion transformer corresponds to the digital input / output voltage terminal DIDO_5V, while the secondary winding T13-B of the conversion transformer is unloaded, reserved for other voltage conversion output circuits, or directly grounded for safety.

[0054] Therefore, the aforementioned MPPT wide-range input and multi-voltage output auxiliary source circuit draws power from the MPPT input and output sides respectively through input and output power-taking diodes. As long as either side has power, it can serve as the auxiliary source bus voltage, ensuring that the auxiliary source always has an output, thus greatly increasing the auxiliary source input range. At the start of the circuit, the sampled voltage is connected to the VCC pin of the auxiliary source chip via a series of resistors. This series of resistors meets the withstand voltage requirements under wide-range input conditions and the power supply current requirements of the auxiliary source chip. When the VCC voltage of the auxiliary source chip rises to the chip's internal threshold voltage, it triggers the chip's internal logic output drive signal. The drive signal passes through an isolation drive circuit and is transmitted to the upper MOSFET Q57 and lower MOSFET Q58 of the dual-transistor flyback circuit. The conduction and turn-off of the two MOSFETs transfer energy from the transformer's primary winding to the secondary winding. The secondary winding outputs 12V and 8V voltages through rectifier diodes. The 12V voltage is then... The optocoupler and the primary-side auxiliary power chip are controlled in a closed loop to stabilize the 12V output. The 12V voltage, after passing through a DC-DC converter, outputs 5V to meet the power supply requirements of other ICs within the MPPT. Simultaneously, a -5V voltage is output through a coupling inductor to meet the negative voltage turn-off requirement of the MPPT's internal main power MOSFET. The 8V voltage, after passing through an LDO circuit, outputs EX_5V to meet customer power supply needs. Furthermore, the 8V voltage, after passing through a secondary-side flyback circuit and various LDO circuits, outputs CAN1_5V, CAN2_5V, 485_1_5V, 485_2_5V, and DIDO_5V to meet various communication voltage requirements. Therefore, this circuit greatly expands the application range of the MPPT and possesses high efficiency and stability, showing broad application prospects.

[0055] It should be noted that the present invention is not limited to the above-described embodiments. Based on the inventive spirit of the present invention, those skilled in the art can make other changes, and these changes made in accordance with the inventive spirit of the present invention should be included within the scope of protection claimed by the present invention.

Claims

1. An MPPT wide-range input and multi-voltage output auxiliary source circuit for use in a multi-channel photovoltaic cell system, comprising an auxiliary source chip U31, characterized in that, It also includes input / output power supply circuits, auxiliary power chip control circuits, isolation drive circuits, dual-transistor flyback circuits, 12V to ±5V circuits, and 8V to multi-channel voltage circuits. The input and output power supply circuit includes an input power supply diode and an output power supply diode. The input power supply diode is connected to the MPPT system input, and the output power supply diode is connected to the MPPT system output to draw power accordingly as the auxiliary source bus voltage. The auxiliary source chip control circuit includes an auxiliary source chip power supply circuit and a feedback circuit. The auxiliary source chip power supply circuit includes a series of voltage divider or current limit resistors, with one end connected to the auxiliary source bus voltage and the other end connected to the power supply pin VCC of the auxiliary source chip U31. The feedback circuit includes an isolation optocoupler circuit. The secondary side of the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31. The anode of the primary side of the isolation optocoupler circuit is connected to a predetermined voltage output, and the cathode is connected to the primary side isolation Zener diode U22. The dual-transistor flyback circuit includes an upper MOSFET Q57, a lower MOSFET Q58, and a flyback transformer. The source of the upper MOSFET Q57 and the drain of the lower MOSFET Q58 are respectively connected to the opposite-named terminal and the same-named terminal of the primary side of the flyback transformer. The flyback transformer has a first flyback secondary winding T1-C and a second flyback secondary winding T1-B. The two flyback secondary windings have corresponding output voltages. The second flyback secondary winding T1-B is connected to a 12V to ±5V circuit, and the first flyback secondary winding T1-C is connected to an 8V to multiplex voltage circuit. The anode and cathode of the primary side of the isolation optocoupler circuit are connected in parallel across the two ends of the second flyback secondary winding. The isolation drive circuit includes an isolation drive transistor Q144, an isolation drive switch Q11, and an isolation drive transformer T4. The base of the isolation drive transistor Q144 and the gate of the isolation drive switch Q11 are connected to the drive pin GATE of the auxiliary source chip U31. The isolation drive transistor Q144 and the isolation drive switch Q11 are connected in series through the primary winding of the isolation drive transformer T4 and are synchronously turned on and off under the signal drive of the drive pin GATE of the auxiliary source chip U31. The secondary side of the isolation drive transformer T4 has a first drive secondary winding and a second drive secondary winding. The two ends of the first drive secondary winding are connected in parallel to the gate and source of the upper MOSFET Q57, and the two ends of the second drive secondary winding are connected in parallel to the gate and source of the lower MOSFET Q58. The upper MOSFET Q57 and the lower MOSFET Q58 are turned on or off synchronously through the first drive secondary winding and the second drive secondary winding. The 12V to ±5V circuit is connected to a DC-DC converter circuit through a rectifier diode D55. The DC-DC converter circuit has a DC-DC converter chip U5. The switch output pin SW of the DC-DC converter chip U5 is connected to a coupling inductor L18. The primary winding L18-A of the coupling inductor L18 outputs 5V, and the secondary winding L18-B of the coupling inductor L18 is reversed to output -5V voltage. The 8V to multi-channel voltage circuit includes a conversion transformer and a multi-channel LDO circuit. The conversion transformer has multiple secondary windings, and each secondary winding is connected to an LDO circuit to output the required voltage.

2. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, There are multiple input power-collecting diodes, each of which is connected to a corresponding photovoltaic cell system. The output power-collecting diodes are connected to the output of the MPPT system. The cathodes of each input or output power-collecting diode are connected to one end of fuse F7. The other end of fuse F7 is connected to one end of thermistor RNTC1. The other end of thermistor RNTC1 is connected to the positive terminal of the first electrolytic capacitor C2. The negative terminal of the first electrolytic capacitor C2 is connected to the positive terminal of the second electrolytic capacitor C37. The negative terminal of the second electrolytic capacitor C37 is grounded. The first electrolytic capacitor C2 and the second electrolytic capacitor C37 are each connected in parallel with at least one resistor for voltage division. The auxiliary power supply bus voltage is obtained between the positive terminal of the first electrolytic capacitor C2 and ground.

3. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 2, characterized in that, The power supply pin VCC of the auxiliary source chip U31 is further connected to the 12V output of the auxiliary source itself; a diode D3 and a fifth current-limiting resistor R674 are connected in series between the power supply pin VCC and the 12V output of the auxiliary source itself; a third electrolytic capacitor and a filter capacitor C47 are connected in parallel between the fifth current-limiting resistor R674 and the power supply pin VCC; the other end of the third electrolytic capacitor and the filter capacitor C47 connected in parallel is grounded.

4. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The auxiliary source chip control circuit also includes an input undervoltage circuit and an output overvoltage circuit. The input undervoltage circuit includes a sampling resistor, one end of which is connected to the auxiliary source bus voltage, and the other end is connected to the undervoltage protection pin BO of the auxiliary source chip U31. An undervoltage regulator unit is also connected between the sampling resistor and the undervoltage protection pin BO of the auxiliary source chip U31. The undervoltage regulator unit includes a parallel voltage regulator resistor R85, an undervoltage regulator capacitor C212, and an undervoltage regulator diode Z5. One end of the undervoltage regulator unit is connected to the sampling resistor and the undervoltage protection pin BO, and the other end is connected to the undervoltage protection pin BO. One end is grounded; the output overvoltage circuit is connected to the detection pin DEMAG of the auxiliary source chip U31; the output overvoltage circuit includes two overvoltage protection resistors R297 and R282 connected in series, the midpoint of the two overvoltage protection resistors R297 and R282 is connected to the detection pin DEMAG of the auxiliary source chip U31, one of the overvoltage protection resistors R282 is connected in parallel with an overvoltage protection capacitor C383 between the midpoint and the ground terminal; one input end of the other overvoltage protection resistor R297 is connected to the auxiliary source bus voltage or the auxiliary source output.

5. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The collector of the secondary-side transistor OT1-A in the isolation optocoupler circuit is connected to the feedback pin FB of the auxiliary source chip U31 through a series resistor R88; a capacitor C214 is connected in parallel between the series resistor R88 of the collector of the secondary-side transistor OT1-A and the emitter, and the capacitor C214 and the emitter are grounded together; the anode of the primary-side LED OT1-B in the isolation optocoupler circuit is connected to the 12V output of the auxiliary source itself after a series and parallel resistor, the cathode of the primary-side LED OT1-B is connected to the primary-side isolation Zener diode U22, and the output pin of the primary-side isolation Zener diode U22 is connected to the same-name terminal of the second flyback secondary winding T1-B; resistors are connected in series and parallel between the pins of the primary-side isolation Zener diode U22 for current shunting or voltage division.

6. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The 12V to ±5V circuit is connected to the input pin VIN of the DC-DC converter chip U5 through a rectifier diode D55. A fourth electrolytic capacitor C35 and a capacitor C17 are connected in parallel between the same-named and opposite-named terminals of the second flyback secondary winding T1-B. The same-named terminal of the second flyback secondary winding T1-B is grounded together with the ground pin of the DC-DC converter chip U5. The inductor secondary winding L18-B is connected to the -5V voltage output terminal L_-5V through a reverse tenth diode D10. The midpoint between the anode of the tenth diode D10 and the -5V voltage output terminal L_-5V is grounded through a fifth electrolytic capacitor C140, and the positive terminal of the fifth electrolytic capacitor C140 is grounded.

7. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The emitter of the isolation driver transistor Q144 is connected to the opposite-named terminal of the primary side of the isolation driver transformer T4. The collector of the isolation driver transistor Q144 is connected to the first auxiliary source output terminal VAUX1. The first auxiliary source output terminal VAUX1 is connected to the power supply pin VCC of the auxiliary source chip U31 or to the 12V output terminal of the step-down auxiliary source itself. The collector of the isolation driver transistor Q144 is connected to the same-named terminal of the primary side of the isolation driver transformer T4 through the ninth Zener diode Z9 and the first zero-one diode D101 connected in reverse. The drain of the isolation driver switch Q11 is connected to the opposite-named terminal of the primary side of the isolation driver transformer T4. The source of the isolation driver switch Q11 is connected to the same-named terminal of the primary side of the isolation driver transformer T4 through a first zero-two diode D102. The anode of the first zero-two diode D102 is connected to the source of the isolation driver switch Q11 and grounded.

8. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 7, characterized in that, The source of the upper MOSFET Q57 is connected to the opposite terminal of the primary winding T1-A of the flyback transformer. The drain of the upper MOSFET Q57 is connected to the auxiliary source bus voltage. The drain of the upper MOSFET Q57 is connected to the same terminal of the primary winding T1-A of the flyback transformer through a reverse thirteenth diode D13. The anode of the thirteenth diode D13 is connected to the same terminal of the primary winding T1-A. The drain of the lower MOSFET Q58 is connected to the same terminal of the primary winding T1-A of the flyback transformer. The source of the lower MOSFET Q58 is connected to the same terminal of the second drive secondary winding and is grounded together through at least one shunt resistor. The opposite terminal of the primary winding T1-A is connected to one end of the shunt resistor grounded through a reverse seventy-second diode D72. The cathode of the seventy-second diode D72 is connected to the opposite terminal of the primary winding T1-A. The same-name terminal of the second driving secondary winding and the source of the lower MOS transistor Q58 are connected to the detection pin CS of the auxiliary source chip U31 through a resistor R239.

9. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The 8V to multi-channel voltage circuit also includes an 8V to EX_5V circuit; the 8V to EX_5V circuit includes a first LDO circuit, the first LDO circuit includes a fourteenth LDO chip U14, the input pin IN of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a twenty-third capacitor C23 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected in parallel with the ground pin GND by a forty-second capacitor C42 and then grounded; the output pin OUT of the fourteenth LDO chip U14 is connected to the EX_5V output terminal of the auxiliary source.

10. The MPPT wide-range input and multi-voltage output auxiliary source circuit as described in claim 1, characterized in that, The 8V output of the first flyback secondary winding T1-C is connected to the power supply pin VDD and enable pins ENA and ENB of a secondary flyback circuit chip U1. The input pin of the secondary flyback circuit chip U1 is connected to a control signal output terminal of the MPPT controller. The 8V to multiplex voltage circuit has multiple conversion transformers. Each conversion transformer includes a primary winding and at least one secondary winding. The two ends of the secondary winding of each conversion transformer are connected in parallel to the input terminal and ground terminal of the corresponding LDO circuit. A capacitor is connected in parallel between the input terminal and ground terminal of each LDO circuit, and another capacitor is connected in parallel between the output terminal and ground terminal. The secondary winding of each conversion transformer... The opposite-named terminal is connected to the input terminal of the corresponding LDO circuit through a forward diode; the same-named terminal of the primary winding of each conversion transformer is connected to the output pin of the secondary flyback circuit chip U1 through a transformer switching transistor; the gate of each transformer switching transistor is connected to the output pin of the secondary flyback circuit chip U1 through a resistor, the drain is connected to the same-named terminal of the corresponding primary winding of the conversion transformer, and the source is grounded; a capacitor is connected in parallel between the drain and source of each transformer switching transistor and then grounded; a filter unit is connected in parallel between the gate and source of each transformer switching transistor and then grounded, the filter unit including a capacitor and a resistor connected in parallel; the opposite-named terminal of the primary winding of each conversion transformer is connected to the 8V output of the first flyback secondary winding T1-C.

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