Photovoltaic optimizer intelligent straight-through mode circuit and control method

Abstract

The invention relates to the technical field of new energy, in particular to a photovoltaic optimizer intelligent straight-through mode circuit and a control method.The photovoltaic optimizer intelligent straight-through mode circuit comprises an optimizer body, a switching control circuit and a straight-through driving circuit, the optimizer body monitors the output voltage and current of a photovoltaic panel, the working point of the photovoltaic panel is dynamically adjusted, and the switching control circuit is switched to the straight-through driving circuit; it is ensured that the photovoltaic panel always operates in the state of outputting the maximum power, and the switching control circuit achieves switching of the optimizer body between an optimization mode and a straight-through mode based on a control signal; the direct-connection driving circuit connects the output of the photovoltaic panel to a load or a power grid, and realizes the automatic switching of the photovoltaic optimizer between an optimization mode and a direct-connection mode through an intelligent switching mechanism, thereby ensuring the efficient operation of the system, enhancing the adaptability and reliability of the system in a complex environment condition, optimizing the overall performance of the photovoltaic system, and improving the reliability of the system. Effective conversion and utilization of energy can be ensured whether in maximum power tracking under an ideal illumination condition or in emergency straight-through operation under a special working condition.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to an intelligent direct-through mode circuit and a control method for a photovoltaic optimizer. Background Art

[0002] In the photovoltaic industry, solar panels (PV panels) are the core devices that convert sunlight directly into electrical energy. However, the output power of PV panels is not fixed, it fluctuates with changes in light intensity, ambient temperature and load conditions. In order to ensure that PV systems can efficiently utilize solar energy and maximize energy harvesting, a key technology is widely used, namely Maximum Power Point Tracking (MPPT). MPPT technology dynamically adjusts its operating point by monitoring the output voltage and current of PV panels in real time to ensure that the system always operates in a state where it can output maximum power. Through a PV MPPT controller (also called a PV optimizer), the overall efficiency of the PV system can be significantly improved even when lighting conditions are not ideal or change over time.

[0003] In this context, in order to further enhance the flexibility and reliability of the system, some photovoltaic optimizers have integrated a "pass-through function". This function allows the output of the photovoltaic panel to be directly connected to the load or the grid by bypassing the MPPT control link under certain conditions. The pass-through function is mainly used in two scenarios: 1. Optimization under low light conditions: When the light is extremely weak, the power generated by the photovoltaic panel is very limited. At this time, the MPPT algorithm may be difficult to work effectively, or the control loss required to track the maximum power point may exceed the increased power gain. Turning off the optimization function and turning on the pass-through function can reduce energy losses in this inefficient state, simplify the circuit, and improve the overall efficiency of the system under weak light conditions; 2. Fail-safe mechanism: As a safety backup measure, if the photovoltaic optimizer fails or requires maintenance, the pass-through function can ensure that the photovoltaic system can continue to supply power. Although it may not be operating at the maximum power point, it at least guarantees the basic energy supply to be uninterrupted.

[0004] In summary, photovoltaic optimizers that combine optimization and pass-through functions play a key role in the photovoltaic field. They not only optimize the energy collection efficiency, but also improve the adaptability and reliability of the system under different working conditions. They are an important guarantee for achieving efficient and stable solar power generation. Summary of the invention

[0005] The purpose of the present invention is to provide a photovoltaic optimizer intelligent direct mode circuit and control method, aiming to realize the automatic conversion of the photovoltaic optimizer between the optimization mode and the direct mode, ensure the efficient operation of the photovoltaic optimizer, and enhance its adaptability and reliability under complex environmental conditions.

[0006] To achieve the above-mentioned object, in a first aspect, the present invention provides a photovoltaic optimizer intelligent direct mode circuit, comprising an optimizer body, a switching control circuit and a direct drive circuit, wherein the optimizer body, the switching control circuit and the direct drive circuit are connected in sequence;

[0007] The optimizer body is used to monitor the output voltage and current of the photovoltaic panel in real time, dynamically adjust the working point of the photovoltaic panel, and ensure that the photovoltaic panel always operates in a state of outputting maximum power;

[0008] The switching control circuit realizes the switching of the optimizer body between the optimization mode and the direct mode based on the control signal;

[0009] The direct drive circuit is used to directly connect the output of the photovoltaic panel to a load or a power grid.

[0010] The switching control circuit includes a high-side N-channel MOS tube Q1, a diode D1, a low-side N-channel MOS tube Q2, a diode D2, an inductor L1, a capacitor C1, a PNP transistor Q3, a resistor R1, a Schottky diode D3, an NPN transistor Q4, a resistor R2, a PNP transistor Q5, a resistor R3, an NPN transistor Q6, a resistor R4, an NPN transistor Q7, a resistor R5 and a resistor R6; the high-side N-channel MOS tube Q1, the low-side N-channel MOS tube Q2, the inductor L1 and the capacitor C1 are connected, and the diode D1 The high-side N-channel MOS transistor Q1 is connected to the diode D2, the low-side N-channel MOS transistor Q2 is connected to the PNP transistor Q3, the resistor R1, the Schottky diode D3, the high-side N-channel MOS transistor Q1 and the PNP transistor Q5 are respectively connected to the resistor R1, the Schottky diode D3, the high-side N-channel MOS transistor Q1 and the PNP transistor Q5, the NPN transistor Q6 is respectively connected to the resistor R3 and the resistor R4, the NPN transistor Q4 is respectively connected to the resistor R1 and the resistor R2, and the NPN transistor Q7 is respectively connected to the resistor R4, the resistor R5 and the resistor R6.

[0011] Among them, the switching control circuit includes a multivibrator OSC, an NPN transistor Q8, a PNP transistor Q9, a resistor R7, a resistor R8, an NPN transistor Q10, a resistor R9, a capacitor C2, a capacitor C3, a Zener diode D3, a Schottky diode D4 and a Schottky diode D5. The resistor R7 is respectively connected to the multivibrator OSC and the NPN transistor Q8, the NPN transistor Q8 is respectively connected to the resistor R7, the resistor R8 and the NPN transistor Q10, the PNP transistor Q9 is respectively connected to the resistor R9, the capacitor C2, the capacitor C3 and the NPN transistor Q10, and the Zener diode D3, the Schottky diode D4 and the Schottky diode D5 are connected.

[0012] The switching control circuit has a built-in protection mechanism to prevent voltage spikes or current shocks at the switching moment.

[0013] In a second aspect, the present invention further provides a photovoltaic optimizer intelligent direct mode circuit control method, which is applied to the photovoltaic optimizer intelligent direct mode circuit as described in the first aspect above, and is characterized in that it includes the following steps:

[0014] When the optimizer body is working normally, the upper tube and the lower tube are controlled by the input PWM signal, the switching control circuit stops, and the optimization mode is entered;

[0015] When the lighting condition deteriorates, the software controls the upper tube input to be disconnected from the PWM signal, connected to the switching control circuit, turns on the direct drive circuit, stops the PWM signal, and the lower tube remains closed, entering the direct mode;

[0016] When the light is restored, the software controls the upper tube to connect to the PWM signal, stops the switching control circuit signal, and starts the switching control signal to enter the optimization mode;

[0017] The software system crashes and the optimizer body control part fails. At this time, the hardware circuit determines that the upper tube is disconnected from the PWM signal by default and connected to the direct drive circuit. The direct drive signal maintains a high level, so that the upper tube is continuously turned on, and the lower tube input is low and continuously turned off, and the whole is in direct mode.

[0018] The present invention provides an intelligent direct-pass mode circuit for a photovoltaic optimizer, wherein the optimizer body monitors the output voltage and current of the photovoltaic panel in real time, dynamically adjusts the working point of the photovoltaic panel, and ensures that the photovoltaic panel always operates in a state of outputting maximum power; the switching control circuit enables the optimizer body to switch between the optimization mode and the direct-pass mode based on a control signal; the direct-pass drive circuit directly connects the output of the photovoltaic panel to a load or a power grid, and the circuit realizes automatic conversion of the photovoltaic optimizer between the optimization mode and the direct-pass mode through an intelligent switching mechanism, thereby ensuring efficient operation of the system and enhancing its adaptability and reliability under complex environmental conditions; the switching control circuit can respond to the control signal and switch between the optimization mode and the direct-pass mode, and this capability is intended to intelligently adjust the working mode according to lighting conditions, system requirements or fault conditions to improve energy conversion efficiency; the switching control circuit has a built-in protection mechanism to prevent Prevent voltage spikes or current shocks at the switching moment, ensure the safety of system components, and extend the service life of the equipment. When the switching control circuit switches to the pass-through mode, the optimizer body ensures that the lower tube is completely turned off, and at the same time, the upper tube receives the appropriate voltage provided by the boost drive circuit, so that the output of the photovoltaic panel is directly transmitted to the load or the power grid, avoiding the extra energy consumption caused by the control link of the optimizer body. It is especially suitable for low-light or special operation and maintenance scenarios, ensuring the basic power supply requirements of the system and reducing unnecessary efficiency losses. The optimizer body is introduced as a fault-safe strategy to ensure that when the control part of the optimizer body fails, the optimizer body automatically enters the pass-through mode, and the system can still maintain the minimum operating capacity, optimize the overall performance of the photovoltaic system, and ensure the effective conversion and utilization of energy whether it is maximum power tracking under ideal lighting conditions or emergency pass-through operation under special working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of an intelligent direct-through mode circuit of a photovoltaic optimizer provided by the present invention.

[0021] Figure 2 The present invention provides a circuit diagram of a switching control circuit of a photovoltaic optimizer intelligent direct mode circuit.

[0022] Figure 3 The present invention provides a circuit diagram of a direct drive circuit of a photovoltaic optimizer intelligent direct mode circuit.

[0023] Figure 4 The present invention provides a flow chart of a photovoltaic optimizer intelligent direct mode circuit control method.

[0024] In the figure: 1-optimizer body, 2-switching control circuit, 3-through drive circuit. DETAILED DESCRIPTION

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0026] See also Figures 1 to 3 In a first aspect, the present invention provides a photovoltaic optimizer intelligent direct mode circuit, comprising an optimizer body 1, a switching control circuit 2 and a direct drive circuit 3, wherein the optimizer body 1, the switching control circuit 2 and the direct drive circuit 3 are connected in sequence;

[0027] The optimizer body 1 is used to monitor the output voltage and current of the photovoltaic panel in real time, dynamically adjust the working point of the photovoltaic panel, and ensure that the photovoltaic panel always operates in a state of outputting maximum power;

[0028] The switching control circuit 2 realizes the switching of the optimizer body 1 between the optimization mode and the direct mode based on the control signal;

[0029] The direct drive circuit 3 is used to directly connect the output of the photovoltaic panel to a load or a power grid.

[0030] In an embodiment of the present invention, the optimizer body 1 monitors the output voltage and current of the photovoltaic panel in real time, dynamically adjusts the working point of the photovoltaic panel, and ensures that the photovoltaic panel always operates in a state of outputting maximum power; the switching control circuit 2 realizes the switching of the optimizer body 1 between the optimization mode and the direct mode based on the control signal; the direct drive circuit 3 directly connects the output of the photovoltaic panel to the load or the power grid. The circuit realizes the automatic conversion of the photovoltaic optimizer between the optimization mode and the direct mode through an intelligent switching mechanism, ensuring the efficient operation of the system while enhancing its adaptability and reliability under complex environmental conditions. The switching control circuit 2 can respond to the control signal and switch between the optimization mode and the direct mode. This capability is intended to intelligently adjust the working mode according to the lighting conditions, system requirements or fault conditions to improve the energy conversion efficiency. The switching control circuit 2 has a built-in protection mechanism to prevent the switching from occurring instantly. voltage spikes or current shocks, ensuring the safety of system components and extending the service life of the equipment. When the switching control circuit 2 switches to the pass-through mode, the optimizer body 1 ensures that the lower tube is completely turned off, and at the same time the upper tube receives the appropriate voltage provided by the boost drive circuit, so that the output of the photovoltaic panel is directly transmitted to the load or the power grid, avoiding the extra energy consumption caused by the control link of the optimizer body 1. It is particularly suitable for low-light or special operation and maintenance scenarios, ensuring the basic power supply requirements of the system, and reducing unnecessary efficiency losses. The optimizer body 1 is introduced as a fault-safe strategy to ensure that when the control part of the optimizer body 1 fails, the optimizer body 1 automatically enters the pass-through mode, and the system can still maintain the minimum operating capacity, optimizing the overall performance of the photovoltaic system, whether it is maximum power tracking under ideal lighting conditions or emergency pass-through operation under special working conditions, it can ensure the effective conversion and utilization of energy.

[0031] Further, the switching control circuit 2 includes a high-side N-channel MOS transistor Q1, a diode D1, a low-side N-channel MOS transistor Q2, a diode D2, an inductor L1, a capacitor C1, a PNP transistor Q3, a resistor R1, a Schottky diode D3, an NPN transistor Q4, a resistor R2, a PNP transistor Q5, a resistor R3, an NPN transistor Q6, a resistor R4, an NPN transistor Q7, a resistor R5 and a resistor R6; the high-side N-channel MOS transistor Q1, the low-side N-channel MOS transistor Q2, the inductor L1 and the capacitor C1 are connected, and the diode D3 is connected to the capacitor C1. D1 is connected to the high-side N-channel MOS transistor Q1, the diode D2 is connected to the low-side N-channel MOS transistor Q2, the PNP transistor Q3 is respectively connected to the resistor R1, the Schottky diode D3, the high-side N-channel MOS transistor Q1 and the PNP transistor Q5, the NPN transistor Q6 is respectively connected to the resistor R3 and the resistor R4, the NPN transistor Q4 is respectively connected to the resistor R1 and the resistor R2, and the NPN transistor Q7 is respectively connected to the resistor R4, the resistor R5 and the resistor R6.

[0032] In an embodiment of the present invention, Vin+ and Vin- of the switching control circuit 2 are connected to the positive and negative poles of the photovoltaic panel as MPPT power input, Vout+ and Vout- are MPPT power outputs, the high-side N-channel MOS tube Q1, the diode D1, the low-side N-channel MOS tube Q2, the diode D2, the inductor L1 and the capacitor C1 constitute a DC-DC buck circuit, Hc (high-side control signal), DRV (through drive signal) and HS (through drive signal reference voltage) are the three input signals of Q1, and the PNP transistor Q3, the resistor R1, the Schottky diode D3, the NPN transistor Q4, the resistor R2, the PNP transistor Q5, the resistor R3, the NPN transistor Q6, the resistor R4, the NPN transistor Q7, the resistor R5 and the resistor R6 constitute the Q1 input control signal switching circuit. To enter the optimization mode, the software controls Hc-EN to a high level, Q4 is turned on, Q3 is turned on, the Hc signal is connected to the gate input HG of Q1, Q7 is turned on, Q6 is turned off, Q5 is turned off, the DRV signal is disconnected from HG, the Hc and Lc levels remain opposite and flip at the same time under the software PWM control, so that Q1 and Q2 are alternately turned on or off, and enter the DC-DC buck power optimization mode. To enter the direct pass mode, the software controls Hc-EN to a low level, Q4 is turned off, Q3 is turned off, the Hc signal is disconnected from HG, Q7 is turned off, Q6 is turned on, Q5 is turned on, the DRV signal is connected to HG, the Hc signal is disconnected from HG, the software PWM is turned off, Lc remains low, and Q2 remains off. Q1 remains on under the drive of the DRV signal and the HS signal, and enters the direct pass mode.

[0033] When the software crashes, the hardware circuit determines that Hc-EN remains at a low level and Lc remains at a low level, which is consistent with the above-mentioned pass-through mode effect. This circuit implements the buck circuit upper tube ( Figure 2 When Hc-EN is high, the input of the upper tube is controlled by PWM; when Hc-EN is low, the input of the upper tube is controlled by DRV.

[0034] Further, the switching control circuit 2 includes a multivibrator OSC, an NPN transistor Q8, a PNP transistor Q9, a resistor R7, a resistor R8, an NPN transistor Q10, a resistor R9, a capacitor C2, a capacitor C3, a Zener diode D3, a Schottky diode D4 and a Schottky diode D5, the resistor R7 is respectively connected to the multivibrator OSC and the NPN transistor Q8, the NPN transistor Q8 is respectively connected to the resistor R7, the resistor R8 and the NPN transistor Q10, the PNP transistor Q9 is respectively connected to the resistor R9, the capacitor C2, the capacitor C3 and the NPN transistor Q10, and the Zener diode D3, the Schottky diode D4 and the Schottky diode D5 are connected.

[0035] In the embodiment of the present invention, the DRV signal and the HS signal are connected to Figure 2 The corresponding signals in the circuit, the multivibrator OSC and Oc (the switching control signal of OSC) constitute the excitation of the driving circuit, the NPN transistor Q8, the PNP transistor Q9, the resistor R7 and the resistor R8 constitute a push-pull circuit, the NPN transistor Q8 and the resistor R7 constitute a push-pull circuit input switch circuit, the capacitor C2, the capacitor C3, the Zener diode D3, the Schottky diode D4 and the Schottky diode D5 constitute an output circuit.

[0036] In optimization mode, Oc is at a low level, OCS has no waveform output to the push-pull circuit input, the push-pull circuit does not work, Q9 and Q10 are cut off, C3 cannot be charged, C2 has no voltage, and DRV has no high voltage to HS.

[0037] When the software controls the pass-through mode or the software crashes, Oc is high, OSC starts to oscillate and generate a square wave, controlling the push-pull circuit to work. When Q10 is turned on and Q9 is turned off, C3 is charged to 12V. When Q10 is turned off and Q9 is turned off, the negative electrode of C3 is raised to the HS level, and C3 charges C2. After multiple times, C2 reaches a voltage of 12V, and DRV maintains a high voltage to HS. Figure 2 The DRV in the middle has a bootstrap boost effect on the HS voltage, thereby driving Figure 2 Q1 is continuously turned on.

[0038] The circuit implements a controllable bootstrap boost function to control whether the voltage difference is output to HG and HS. When output to HG and HS, the upper tube can be kept turned on continuously. When the program crashes, this function is enabled by default to keep the upper tube turned on continuously.

[0039] See also Figure 4 In a second aspect, the present invention further provides a photovoltaic optimizer intelligent direct mode circuit control method, which is applied to the photovoltaic optimizer intelligent direct mode circuit as described in the first aspect above, and is characterized in that it includes the following steps:

[0040] S1 When the optimizer body 1 works normally, the upper tube and the lower tube are controlled by the input PWM signal, the switching control circuit 2 is stopped, and the optimization mode is entered;

[0041] S2: The lighting condition deteriorates, the software controls the upper tube input to be disconnected from the PWM signal, connected to the switching control circuit 2, turns on the direct drive circuit 3, stops the PWM signal, and the lower tube remains closed, entering the direct mode;

[0042] S3: The illumination is restored, the software controls the upper tube to connect to the PWM signal, stops the switching control circuit 2 signal, and starts the switching control signal to enter the optimization mode;

[0043] The S4 software system crashes, and the control part of the optimizer body 1 fails. At this time, the hardware circuit determines that the upper tube is disconnected from the PWM signal by default and connected to the direct drive circuit 3. The direct drive signal maintains a high level, so that the upper tube is continuously turned on, and the lower tube input is low and continuously turned off, and the whole is in direct mode.

[0044] In order to better understand the present technical solution, the following embodiments are provided for further explanation:

[0045] Embodiment 1:

[0046] In the PV optimizer, Figure 2 As shown, a switching circuit is added to the input control signal of the upper tube of the DC-DC buck circuit to realize the switching control of different input signals in the optimization mode and the pass-through mode. As shown in if 3, a pass-through drive is added to the gate and drain of the upper tube of the DC-DC buck circuit, and the switch control of the pass-through drive circuit 3 is performed to realize software control to enter the pass-through mode or software crash to enter the pass-through mode.

[0047] The above disclosure is only a preferred embodiment of a photovoltaic optimizer intelligent direct mode circuit and control method of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention are still within the scope of the invention.

Claims

1. A photovoltaic optimizer intelligent direct mode circuit, characterized in that: It includes an optimizer body, a switching control circuit and a through-drive circuit, wherein the optimizer body, the switching control circuit and the through-drive circuit are connected in sequence; The optimizer body is used to monitor the output voltage and current of the photovoltaic panel in real time, dynamically adjust the working point of the photovoltaic panel, and ensure that the photovoltaic panel always operates in a state of outputting maximum power; The switching control circuit realizes the switching of the optimizer body between the optimization mode and the direct mode based on the control signal; The direct drive circuit is used to directly connect the output of the photovoltaic panel to a load or a power grid.

2. The photovoltaic optimizer intelligent direct mode circuit according to claim 1, characterized in that: The switching control circuit includes a high-side N-channel MOS transistor Q1, a diode D1, a low-side N-channel MOS transistor Q2, a diode D2, an inductor L1, a capacitor C1, a PNP transistor Q3, a resistor R1, a Schottky diode D3, an NPN transistor Q4, a resistor R2, a PNP transistor Q5, a resistor R3, an NPN transistor Q6, a resistor R4, an NPN transistor Q7, a resistor R5 and a resistor R6; the high-side N-channel MOS transistor Q1, the low-side N-channel MOS transistor Q2, the inductor L1 and the capacitor C1 are connected, and the diode D1 is connected to The high-side N-channel MOS transistor Q1 is connected, the diode D2 is connected to the low-side N-channel MOS transistor Q2, the PNP transistor Q3 is respectively connected to the resistor R1, the Schottky diode D3, the high-side N-channel MOS transistor Q1 and the PNP transistor Q5, the NPN transistor Q6 is respectively connected to the resistor R3 and the resistor R4, the NPN transistor Q4 is respectively connected to the resistor R1 and the resistor R2, and the NPN transistor Q7 is respectively connected to the resistor R4, the resistor R5 and the resistor R6.

3. The photovoltaic optimizer intelligent direct mode circuit according to claim 1, characterized in that: The switching control circuit includes a multivibrator OSC, an NPN transistor Q8, a PNP transistor Q9, a resistor R7, a resistor R8, an NPN transistor Q10, a resistor R9, a capacitor C2, a capacitor C3, a Zener diode D3, a Schottky diode D4 and a Schottky diode D5. The resistor R7 is respectively connected to the multivibrator OSC and the NPN transistor Q8, the NPN transistor Q8 is respectively connected to the resistor R7, the resistor R8 and the NPN transistor Q10, the PNP transistor Q9 is respectively connected to the resistor R9, the capacitor C2, the capacitor C3 and the NPN transistor Q10, and the Zener diode D3, the Schottky diode D4 and the Schottky diode D5 are connected.

4. The photovoltaic optimizer intelligent direct mode circuit according to claim 1, characterized in that: The switching control circuit has a built-in protection mechanism to prevent voltage spikes or current shocks at the switching moment.

5. A photovoltaic optimizer intelligent direct mode circuit control method, applied to the photovoltaic optimizer intelligent direct mode circuit according to any one of claims 1 to 4, characterized in that: The following steps are involved: When the optimizer body is working normally, the upper tube and the lower tube are controlled by the input PWM signal, the switching control circuit stops, and the optimization mode is entered; When the lighting condition deteriorates, the software controls the upper tube input to be disconnected from the PWM signal, connected to the switching control circuit, turns on the direct drive circuit, stops the PWM signal, and the lower tube remains closed, entering the direct mode; When the light is restored, the software controls the upper tube to connect to the PWM signal, stops the switching control circuit signal, and starts the switching control signal to enter the optimization mode; The software system crashes and the optimizer body control part fails. At this time, the hardware circuit determines that the upper tube is disconnected from the PWM signal by default and connected to the direct drive circuit. The direct drive signal maintains a high level, so that the upper tube is continuously turned on, and the lower tube input is low and continuously turned off, and the whole is in direct mode.

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