Photovoltaic power generation inverter and power control method

Abstract

This application provides a photovoltaic inverter and a power control method. The photovoltaic inverter includes an inverter circuit, a plurality of voltage conversion circuits, a plurality of acquisition circuits, and a control circuit. . system The circuit is ,Ta When the input current of the target voltage conversion circuit is equal to or greater than a current threshold of the target voltage conversion circuit, a switch in the target voltage conversion circuit is turned on or off to reduce the current or input power of the target voltage conversion circuit. control According to this application, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the input power of the voltage conversion circuit is reduced to ensure the safety of the power supply, and the stability and power supply efficiency of the photovoltaic power generation inverter can be improved. 。

Description

Technical Field

[0001] This The application relates to the field of power electronics technology, and in particular, to a solar power inverter and a power control method.

Background Art

[0002] In the field of power electronics technology, an inverter circuit in a solar power inverter is usually used to convert DC energy into AC energy so that electrical energy can be transmitted between a power source and a load. For example, in the field of solar power generation power sources, a solar power inverter converts DC energy output by a DC power source (for example, a photovoltaic (PV) panel) into AC energy and can provide the AC energy for use by a load or a power grid. Generally, a control circuit (for example, a maximum power point tracking (MPPT) control circuit) in the solar power inverter controls the output current of the PV panel (that is, the input current of the solar power inverter) based on the output voltage of the PV panel (that is, the input voltage of the solar power inverter) so that the PV panel outputs electrical energy to the load at the maximum power. In the process of research and practice, the inventor of this application found that in the prior art, a solar power inverter usually uses a plurality of voltage conversion circuits to convert the DC voltage provided by each group of PV panels into a DC bus voltage (for example, boosting and converting the voltage of each group of PV panels), and then uses an inverter circuit to convert DC energy into AC energy to adapt to the voltages of various loads. There are differences between groups of PV panels (for example, different lengths or different light intensities). Therefore, the output voltage of the PV panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the This electricity bus This electricityWhen the difference from the pressure is excessively large, usually the input current in the voltage conversion circuit is high. As a result, due to overvoltage, overcurrent, or overheating, a failure or damage may be caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit.

Summary of the Invention

[0003] This application provides a solar power generation inverter and a power control method. When the input current of the target voltage conversion circuit is equal to or higher than the current threshold of the target voltage conversion circuit, the duty cycle of the switch can be adjusted via a control circuit so as to reduce the input power of the voltage conversion circuit, thereby improving the stability of the solar power generation inverter and the power supply efficiency while ensuring the safety of the power supply. The structure is simple, the method is simple, and the applicability is high.

[0004] [[ID=II]]According to a first aspect, this application provides a solar power generation inverter. The solar power generation inverter may include an inverter circuit, a plurality of voltage conversion circuits, a plurality of acquisition circuits, and a control circuit. One voltage conversion circuit may include at least one switch. Here, one end of each voltage conversion circuit may be configured to be connected corresponding to each of a plurality of groups of solar power generation panels. The other end of each voltage conversion circuit may be configured to be connected to a load via the inverter circuit after being connected in parallel. The plurality of acquisition circuits may be connected to the control circuit and configured to detect voltage or current. The control circuit is connected to the switches within each voltage conversion circuit. Here, the plurality of acquisition circuits may be configured to detect the input voltage of the target voltage conversion circuit and voltage. The target voltage conversion circuit is one or more of the plurality of voltage conversion circuits. Here, the control circuit is the input voltage of the target voltage conversion circuit and This to It may be configured to be connected to the load via the inverter circuit after being connected in parallel. The above-mentioned plurality of acquisition circuits are connected to the control circuit and This of May be configured to detect voltage or current. The control circuit is connected to the switches within each voltage conversion circuit. Here, the plurality of acquisition circuits may be configured to detect the input voltage of the target voltage conversion circuit and This of Voltage. The target voltage conversion circuit is one or more of the plurality of voltage conversion circuits. Here, the control circuit is the input voltage of the target voltage conversion circuit and This ofBased on the voltage, the current threshold of the target voltage conversion circuit can be adjusted. Here, the control circuit further adjusts the duty cycle of the switch in the target voltage conversion circuit to reduce the current or input power of the target voltage conversion circuit when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, so as to turn on or off the switch in the target voltage conversion circuit. Control It can be configured to do so.

[0005] In this application, the solar power generation panel can be connected to the load as a DC power source via the solar power generation inverter. The solar power generation inverter can convert the DC energy provided by the solar power generation panel into AC energy and provide the AC energy to the load. Here, the solar power inverter can include an inverter circuit and a plurality of voltage conversion circuits. The DC power source can include a plurality of groups of solar power generation panels (each group of solar power generation panels can include one solar power generation panel or a plurality of solar power generation panels). Each group of solar power generation panels can be connected to the inverter circuit via one voltage conversion circuit. The voltage conversion circuit can convert the DC voltage provided by the solar power generation panel into a voltage, and then convert the DC energy into AC energy through the inverter circuit so that the AC voltage output by the solar power generation inverter can adapt to loads within a plurality of voltage ranges. In an application scenario including a plurality of groups of solar power generation panels, there are differences between the groups of solar power generation panels (for example, different lengths, different shapes, or different light intensities). Therefore, the output voltage of the solar power generation panel connected to the voltage conversion circuit (i.e., the input voltage of the voltage conversion circuit) and This electricity voltage This electricityWhen the difference from the voltage is excessively large, usually the input current in the voltage conversion circuit is high. As a result, due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high), a failure or damage may be caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit. Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit may detect the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, the voltage and / or current, the input voltage and / or output voltage of the inverter circuit, the input current and / or output current of the inverter circuit, and the temperature of the inverter circuit). Here, the control circuit may determine the operating state of the solar power generation inverter based on the power supply parameters of the solar power generation inverter. Here, an example is used where one (or more) voltage conversion circuits that need to be controlled by the control circuit is the target voltage conversion circuit. The control circuit may adjust the current threshold of the target voltage conversion circuit based on the input voltage and the voltage of the target voltage conversion circuit. After the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, in order to protect the operating safety of the voltage conversion circuit, the control circuit may adjust the duty cycle of the switch in the target voltage conversion circuit (for example, reduce the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit. This of Based on the input voltage and / or output voltage of the inverter circuit, the input current and / or output current of the inverter circuit, and the temperature of the inverter circuit), it may be detected. Here, the control circuit may determine the operating state of the solar power generation inverter based on the power supply parameters of the solar power generation inverter. Here, an example is used where one (or more) voltage conversion circuits that need to be controlled by the control circuit is the target voltage conversion circuit. The control circuit may adjust the current threshold of the target voltage conversion circuit based on the input voltage and the voltage of the target voltage conversion circuit. After the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, in order to protect the operating safety of the voltage conversion circuit, the control circuit may adjust the duty cycle of the switch in the target voltage conversion circuit (for example, reduce the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit. This of Based on the voltage, the control circuit may adjust the current threshold of the target voltage conversion circuit. After the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, in order to protect the operating safety of the voltage conversion circuit, the control circuit may adjust the duty cycle of the switch in the target voltage conversion circuit (for example, reduce the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit. Control It can be done.

[0006] According to this application, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the solar power generation inverter can adjust the duty cycle of the switch through the control circuit to reduce the input power of the voltage conversion circuit, thereby improving the stability of the solar power generation inverter and the power supply efficiency while ensuring the safety of the power supply. The structure is simple, the method is simple, and the applicability is high.

[0007] Referring to the first aspect, in a first possible implementation, the acquisition circuit may further be configured to detect the temperature of the target voltage conversion circuit. The control circuit may further, when the temperature of the target voltage conversion circuit is equal to or higher than a temperature threshold, based on the input voltage and the bus voltage of the target voltage conversion circuit, be configured to adjust the current threshold of the target voltage conversion circuit to a first current threshold. It can be understood that the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and further can determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and further can determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is equal to or higher than the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage difference borne by the switches is the same, the input currents that the switches can withstand may be different. For example, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold), the control circuit may determine the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the bus This of voltage) and the current threshold of the target voltage conversion circuit, and then adjust the input current and / or input power of the target voltage conversion circuit according to the determined operating state. In addition, when the input voltage of the target voltage conversion circuit is lower than a certain value, the control circuit may also determine whether it is necessary to increase the input power of the target voltage conversion circuit according to the determined operating state. This ofBased on the difference from the voltage, the maximum input current (e.g., the first current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Note that the value of the first current threshold can be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., based on the corresponding nominal current when switches of various models bear different voltage differences), or it can be determined based on the current threshold obtained by the photovoltaic inverter in a manner such as acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (e.g., the first operating temperature range above the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can obtain the first current threshold based on this curve. The first current threshold can be specifically set based on the application scenario. It can be understood that the first current threshold here can be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents.

[0008] In this application, when the operating temperature of the switch in the target voltage conversion circuit is high (e.g., the temperature of the target voltage conversion circuit is above the temperature threshold), if the input current of the switch in the target voltage conversion circuit is above the first current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit can reduce the duty cycle of the switch in the target voltage conversion circuit to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the electrical energy transmission efficiency on the basis of ensuring safety.

[0009] Referring to the first possible implementation of the first aspect, in a second possible implementation, the control circuit further, when the temperature of the target voltage conversion circuit is less than the temperature threshold, based on the input voltage of the target voltage conversion circuit and the This of voltage, may be configured to adjust the current threshold of the target voltage conversion circuit to a second current threshold. The second current threshold is greater than or equal to the first current threshold. It can be understood that the control circuit can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage difference borne by the switches is the same, the input currents that the switches can withstand may be different. For example, when the operating temperature of the switch in the target voltage conversion circuit is low (for example, the temperature of the target voltage conversion circuit is less than the temperature threshold), the control circuit is the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the This ofBased on the difference between the voltage (e.g., the difference between the first voltage threshold and the voltage at a certain point), the maximum input current (e.g., the second current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Here, the second current threshold is smaller than the first voltage threshold. Note that the value of the second current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., based on the corresponding nominal current when switches of various models bear different voltage differences), or it may be determined based on the current threshold obtained by the photovoltaic inverter through means such as acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (e.g., the second operating temperature range lower than the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can obtain the second current threshold based on this curve. The second current threshold can be specifically set based on the application scenario. It can be understood that the second current threshold here may be one current, or multiple discrete currents, or a current range including multiple discrete currents or continuous currents.

[0010] In this application, when the operating temperature of the switch in the target voltage conversion circuit is low (e.g., the temperature of the target voltage conversion circuit is lower than the temperature threshold), if the input current of the switch in the target voltage conversion circuit is equal to or greater than the second current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the transmission efficiency of electrical energy on the basis of ensuring safety.

[0011] Referring to the first aspect or any possible implementation of the first aspect, in a third possible implementation, the control circuit further generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, and based on the switching modulation signal, the duty cycle of the switch in the target voltage conversion circuit is Adjustment adjusted to turn on or turn off the switch in the target voltage conversion circuit. Control Here, the control circuit (for example, a current adjustment loop (for example, a proportional adjustment circuit or a proportional integral adjustment circuit) and a drive control circuit, or another circuit having a current adjustment function and a drive control function) generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit to adjust the duty cycle of the switch in the target voltage conversion circuit. Adjustment For example, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the control circuit generates a reference value smaller than the current threshold based on the current threshold of the target voltage conversion circuit, and by using the input current of the target voltage conversion circuit as a variable to be adjusted, generates a switching modulation signal for adjusting the duty cycle of the switch in the target voltage conversion circuit based on the switching modulation signal, so as to adjust the input current in the target voltage conversion circuit to be less than the current threshold of the target voltage conversion circuit (that is, the above-mentioned reference value). Here, the control circuit can generate a signal such as a Pulse Width Modulation (PWM) wave as the switching modulation signal, or can generate a drive pulse signal as the switching modulation signal based on the PWM wave. Here, the switching modulation signal adjusts the duty cycle of the switch in the target voltage conversion circuit. Adjustment Adjustment ​Moreover, the input current and / or input power of the target voltage conversion circuit can be controlled. For example, the control circuit can reduce the duty cycle of the switch in the target voltage conversion circuit to reduce the input current of the target voltage conversion circuit and reduce the input power of the target voltage conversion circuit. It can be understood that the control circuit provided in this application may use a discontinuous pulse width modulation (DPWM) wave as the switching modulation signal, or may use another PWM wave (for example, a sinusoidal pulse width modulation (SPWM) wave, a third harmonic injection pulse width modulation (THIPWM) wave, or a carrier based space vector pulse width modulation (CBPWM) wave) as the switching modulation signal, or may use a drive pulse signal generated based on these PWM waves as the switching modulation signal. The applicable range is wide and the control effect is good.

[0012] Referring to the first aspect or any possible implementation of the first aspect, in a fourth possible implementation, the control circuit further, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit, adjusts the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power, and turns on or off the switch in the target voltage conversion circuit Control can be configured to do so.

[0013] Here, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit (for example, the third current threshold), the target voltage conversion circuit can be considered to be in an operating state where it is not necessary to reduce the input power (in other words, the switch in the target voltage conversion circuit is operating in a safe environment with a low risk of damage). In this case, the control circuit can adjust the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the photovoltaic panel connected to the target voltage conversion circuit operates at the maximum power point). Here, the value of the third current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, determined based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold acquired by the photovoltaic inverter by means such as acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences in a specific operating temperature or a specific operating temperature range (for example, the first operating temperature range above the temperature threshold, or the second operating temperature range below the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can acquire the third current threshold based on the curve. The third current threshold can be specifically set based on the application scenario. It can be understood that the third current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents. For example, in the first operating temperature range above the temperature threshold, the third current threshold can be set to be less than or equal to the first current threshold. In another example, in the second operating temperature range below the temperature threshold, the third current threshold can be set to be less than or equal to the second current threshold. When the third voltage threshold is smaller than the first current threshold (or the second current threshold), the photovoltaic inverter can avoid repeatedly decreasing or increasing the input power of the target voltage conversion circuit via the control circuit when the input current of the target voltage conversion circuit does not stably become smaller than the first current threshold (or the second current threshold).In other words, when the third voltage threshold is less than the first current threshold (or the second current threshold), after the input current of the target voltage conversion circuit has stabilized (for example, stably less than the third current threshold), the target voltage conversion circuit of the solar power generation inverter may be in an operating state where it is not necessary to reduce the input power (or, in other words, the switches in the target voltage conversion circuit are operating in a safe environment with a low risk of damage). In this case, the control circuit may adjust the duty cycle of the switches in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the solar power generation panel connected to the target voltage conversion circuit operates at the maximum power point). This improves the power supply efficiency.

[0014] Referring to the first aspect or any possible implementation of the first aspect, in a fifth possible implementation, the inverter circuit may include switches. The control circuit may further... This of When the voltage is equal to or higher than the bus voltage threshold, adjust the duty cycle of the switches in the inverter circuit to turn on or off the switches in the inverter circuit so as to reduce the output power of the inverter circuit. Control It can be understood that the control circuit can determine the operating state of the solar power generation inverter in a plurality of ways, and can further determine whether it is necessary to control the output power (or output current) of the solar power generation inverter (for example, the inverter circuit). For example, when the bus voltage is equal to or higher than the bus voltage threshold, the inverter circuit may be in an operating state where it is necessary to reduce the output power (or, in other words, each element in the solar power generation inverter is operating in a harsh environment and will be damaged at a high risk if it continues to operate). In this case, the control circuit needs to reduce the output current and / or output power of the inverter circuit. It can be understood that the bus voltage threshold here may be one voltage, or a plurality of discrete voltages, or a voltage range including a plurality of discrete voltages or continuous voltages. This of When the bus voltage is equal to or higher than the bus voltage threshold, the inverter circuit may be in an operating state where it is necessary to reduce the output power (or, in other words, each element in the solar power generation inverter is operating in a harsh environment and will be damaged at a high risk if it continues to operate). In this case, the control circuit needs to reduce the output current and / or output power of the inverter circuit. It can be understood that the bus voltage threshold here may be one voltage, or a plurality of discrete voltages, or a voltage range including a plurality of discrete voltages or continuous voltages.

[0015] In this application, when the voltage of B This of is high (for example, when the voltage of B This of is equal to or higher than the bus voltage threshold), it indicates that the photovoltaic power generation inverter is in an operating state where it is necessary to reduce the output power. The control circuit reduces the duty cycle of each switch in the inverter circuit, further reducing the output power of the inverter circuit to avoid damage to the elements in the photovoltaic power generation inverter due to overheating, and can further improve the safety of power supply.

[0016] According to a second aspect, this application provides a power control method. The control method is applicable to a photovoltaic power generation system. The photovoltaic power generation system may include an inverter circuit, a plurality of voltage conversion circuits, an acquisition circuit, and a control circuit. One voltage conversion circuit may include at least one switch. Here, one end of each voltage conversion circuit may be configured to be connected corresponding to each of a plurality of groups of photovoltaic power generation panels. The other end of each voltage conversion circuit may be configured to be connected in parallel and then connected to a load through the inverter circuit. The acquisition circuit is connected to each voltage conversion circuit, B This to and the control circuit. The control circuit is connected to the switches in each voltage conversion circuit. The method includes This, detecting the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the voltage of B where the target voltage conversion circuit is any one or more of the plurality of voltage conversion circuits, and based on the input voltage of the target voltage conversion circuit and the voltage of B This of adjusting the current threshold of the target voltage conversion circuit, and when the input current of the target voltage conversion circuit is equal to or higher than the current threshold of the target voltage conversion circuit, adjusting the duty cycle of the switch in the target voltage conversion circuit to turn on or off the switch in the target voltage conversion circuit so as to reduce the current or input power of the target voltage conversion circuit. This of This may be included. Control

[0017] In this application, a solar power generation panel can be connected to a load as a DC power source via a solar power generation inverter. The solar power generation inverter can convert the DC energy provided by the solar power generation panel into AC energy and supply the AC energy to the load. Here, the solar power generation inverter may include an inverter circuit and a plurality of voltage conversion circuits. The DC power source may include a plurality of groups of solar power generation panels (each group of solar power generation panels may include one solar power generation panel or a plurality of solar power generation panels). Each group of solar power generation panels can be connected to the inverter circuit via one voltage conversion circuit. The voltage conversion circuit can convert the DC voltage provided by the solar power generation panel into a voltage, and then convert the DC energy into AC energy through the inverter circuit so that the AC voltage output by the solar power generation inverter can be adapted to loads within a plurality of voltage ranges. In an application scenario including a plurality of groups of solar power generation panels, there are differences between the groups of solar power generation panels (for example, different lengths, different shapes, or different light intensities). Therefore, when the difference between the output voltage of the solar power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, faults or damages may be caused to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit) due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high). Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit can acquire the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This electricity When the difference between the voltage conversion circuit and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, faults or damages may be caused to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit) due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high). In an application scenario including a plurality of groups of solar power generation panels, there are differences between the groups of solar power generation panels (for example, different lengths, different shapes, or different light intensities). Therefore, when the difference between the output voltage of the solar power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, faults or damages may be caused to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit) due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high). Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit can acquire the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This electricity When the difference between the output voltage of the solar power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, faults or damages may be caused to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit) due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high). In an application scenario including a plurality of groups of solar power generation panels, there are differences between the groups of solar power generation panels (for example, different lengths, different shapes, or different light intensities). Therefore, when the difference between the output voltage of the solar power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, faults or damages may be caused to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit) due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high). Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit can acquire the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This ofIt is possible to detect (voltage and / or current, input voltage and / or output voltage of the inverter circuit, input current and / or output current of the inverter circuit, and temperature of the inverter circuit). Here, the control circuit can determine the operating state of the photovoltaic power generation inverter based on the power parameters of the photovoltaic power generation inverter. Here, an example where one (or more) voltage conversion circuits that need to be controlled by the control circuit is the target voltage conversion circuit is used. The control circuit can adjust the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the This of bus voltage. After the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, in order to protect the operating safety of the voltage conversion circuit, the control circuit can adjust the duty cycle of the switch in the target voltage conversion circuit (for example, reduce the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit so as to reduce the current or input power of the target voltage conversion circuit. Control It can be done.

[0018] According to this application, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the photovoltaic power generation inverter can adjust the duty cycle of the switch through the control circuit to reduce the input power of the voltage conversion circuit, thereby improving the stability of the photovoltaic power generation inverter and the power supply efficiency while ensuring the safety of power supply. The structure is simple, the method is simple, and the applicability is high.

[0019] Referring to the second aspect, in a first possible implementation, adjusting the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the This of bus voltage may include detecting the temperature of the target voltage conversion circuit, and when the temperature of the target voltage conversion circuit is greater than or equal to the temperature threshold, adjusting the current threshold of the target voltage conversion circuit to a first current threshold based on the input voltage of the target voltage conversion circuit and the bus voltage. This of It may include the above.

[0020] It can be understood that the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, it can be considered that the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage differences borne by the switches are the same, the input currents that the switches can withstand can be different. For example, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold), the control circuit can determine the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the b This ofBased on the difference from the voltage, the maximum input current (e.g., the first current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Note that the value of the first current threshold can be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., based on the corresponding nominal current when switches of various models bear different voltage differences), or it can be determined based on the current threshold obtained by the solar power generation inverter in a manner such as acquisition, collection, reception, detection, or storage. For example, the solar power generation inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (e.g., the first operating temperature range above the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can obtain the first current threshold based on this curve. The first current threshold can be specifically set based on the application scenario. It can be understood that the first current threshold here can be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents.

[0021] In this application, when the operating temperature of the switch in the target voltage conversion circuit is high (e.g., the temperature of the target voltage conversion circuit is above the temperature threshold) and the input current of the switch in the target voltage conversion circuit is above the first current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the electrical energy transmission efficiency on the basis of ensuring safety.

[0022] Referring to the first possible implementation of the second aspect, in the second possible implementation, after detecting the temperature of the target voltage conversion circuit, the method further when the temperature of the target voltage conversion circuit is less than the temperature threshold, based on the input voltage and the This of bus voltage of the target voltage conversion circuit, adjusting the current threshold of the target voltage conversion circuit to a second current threshold, where the second current threshold is greater than or equal to the first current threshold, may be included.

[0023] It can be understood that the control circuit can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperature of the switch in the target voltage conversion circuit is different, even if the voltage difference borne by the switch is the same, the input current that the switch can withstand can be different. For example, when the operating temperature of the switch in the target voltage conversion circuit is low (for example, the temperature of the target voltage conversion circuit is less than the temperature threshold), the control circuit is based on the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the This ofBased on the difference between the voltage (e.g., the difference between the first voltage threshold and the voltage), the maximum input current that the switch in the target voltage conversion circuit can withstand (e.g., the second current threshold) can be determined. Here, the second current threshold is smaller than the first voltage threshold. Note that the value of the second current threshold can be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., based on the corresponding nominal current when switches of various models bear different voltage differences), or it can be determined based on the current threshold obtained by the photovoltaic inverter in a manner such as acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (e.g., the second operating temperature range lower than the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can obtain the second current threshold based on this curve. The second current threshold can be specifically set based on the application scenario. It can be understood that the second current threshold here can be one current, or multiple discrete currents, or even a current range including multiple discrete currents or continuous currents.

[0024] In this application, when the operating temperature of the switch in the target voltage conversion circuit is low (e.g., the temperature of the target voltage conversion circuit is lower than the temperature threshold) and the input current of the switch in the target voltage conversion circuit is equal to or greater than the second current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit can reduce the duty cycle of the switch in the target voltage conversion circuit to further reduce the input power of the target voltage conversion circuit, thereby avoiding damage to the elements in the target voltage conversion circuit due to overheating and improving the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the transmission efficiency of electrical energy on the basis of ensuring safety.

[0025] Referring to the second possible implementation of the second aspect, in the third possible implementation, after adjusting the current threshold of the target voltage conversion circuit based on the input voltage and the bus voltage of the target voltage conversion circuit, the method further This of includes generating a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, and controlling the duty cycle of the switch in the target voltage conversion circuit based on the switching modulation signal to turn on or off the switch in the target voltage conversion circuit, which may be the case. Control Here, a control circuit (for example, a current adjustment loop (for example, a proportional adjustment circuit or a proportional integral adjustment circuit) and a drive control circuit, or another circuit having a current adjustment function and a drive control function) generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit to

[0026] control the duty cycle of the switch in the target voltage conversion circuit. For example, the control circuit can generate a signal such as a sine wave as the switching modulation signal, or can generate a drive pulse signal as the switching modulation signal based on a PWM wave. Here, the switching modulation signal controls the duty cycle of the switch in the target voltage conversion circuit and further can control the input current and / or input power of the target voltage conversion circuit. For example, the control circuit can reduce the duty cycle of the switch in the target voltage conversion circuit to reduce the input current of the target voltage conversion circuit and reduce the input power of the target voltage conversion circuit. It can be understood that the control circuit provided in this application can use a sine wave as the switching modulation signal, or another PWM wave (for example, a triangular wave, Adjustment a sawtooth wave, or PWM a square wave) as the switching modulation signal. Adjustment It can be understood that the control circuit provided in this application can use a sine wave as the switching modulation signal, or another PWM wave (for example, a triangular wave, DPWM a sawtooth wave, or SPWM a square wave) as the switching modulation signal. THIPWM a square wave, or CBPWMWaves may be used, or drive pulse signals generated based on these PWM waves as switching modulation signals may be used. The applicable range is wide and the control effect is good.

[0027] Referring to the second aspect or any possible implementation of the second aspect, in a fourth possible implementation, after adjusting the current threshold of the target voltage conversion circuit based on the input voltage and the bus voltage of the target voltage conversion circuit, the method further This of includes, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit, adjusting the duty cycle of the switch in the target voltage conversion circuit to turn on or turn off the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power. This may include doing so. Control

[0028] Here, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit (for example, the third current threshold), the target voltage conversion circuit may be considered to be in an operating state where it is not necessary to reduce the input power (in other words, the switch in the target voltage conversion circuit is operating in a safe environment with a low risk of damage). In this case, the control circuit can adjust the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the photovoltaic panel connected to the target voltage conversion circuit operates at the maximum power point). Here, the value of the third current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, determined based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold obtained by the photovoltaic inverter in a manner such as acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences in a specific operating temperature or a specific operating temperature range (for example, the first operating temperature range above the temperature threshold, or the second operating temperature range below the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit can obtain the third current threshold based on the curve. The third current threshold can be specifically set based on the application scenario. It can be understood that the third current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents. For example, in the first operating temperature range above the temperature threshold, the third current threshold can be set to be less than or equal to the first current threshold. In another example, in the second operating temperature range below the temperature threshold, the third current threshold can be set to be less than or equal to the second current threshold. When the third voltage threshold is smaller than the first current threshold (or the second current threshold), the photovoltaic inverter can avoid repeatedly decreasing or increasing the input power of the target voltage conversion circuit via the control circuit when the input current of the target voltage conversion circuit does not stably become smaller than the first current threshold (or the second current threshold).In other words, when the third voltage threshold is less than the first current threshold (or the second current threshold), after the input current of the target voltage conversion circuit has stabilized (for example, stably less than the third current threshold), the target voltage conversion circuit of the photovoltaic inverter may be in an operating state where it is not necessary to reduce the input power (or, in other words, the switches in the target voltage conversion circuit are operating in a safe environment with a low risk of damage). In this case, the control circuit may adjust the duty cycle of the switches in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the photovoltaic panel connected to the target voltage conversion circuit operates at the maximum power point). This improves the power supply efficiency.

[0029] Referring to the second aspect or any possible implementation of the second aspect, in a fifth possible implementation, the inverter circuit may include switches. After detecting the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the bus voltage, the method may further include This of adjusting the duty cycle of the switches in the inverter circuit to turn on or off the switches in the inverter circuit so as to reduce the output power of the inverter circuit when the bus voltage is greater than or equal to the bus voltage threshold. bus This of It can be understood that the control circuit can determine the operating state of the photovoltaic inverter in a plurality of ways, and can further determine whether it is necessary to control the output power (or output current) of the photovoltaic inverter (for example, the inverter circuit). For example, bus Control including

[0030] It can be understood that the control circuit can determine the operating state of the photovoltaic inverter in multiple ways, and can further determine whether it is necessary to control the output power (or output current) of the photovoltaic inverter (for example, the inverter circuit). For example, bus This ofWhen the voltage is equal to or higher than the bus voltage threshold, the inverter circuit may be in an operating state where it is necessary to reduce the output power (or, in other words, each element within the photovoltaic power generation inverter is operating in a harsh environment and will be damaged at high risk if it continues to operate). In this case, the control circuit needs to reduce the output current and / or output power of the inverter circuit. It can be understood that the bus voltage threshold here may be a single voltage, or a plurality of discrete voltages, or a voltage range including a plurality of discrete voltages or continuous voltages.

[0031] In this application, the bus This of When the voltage is high (for example, the bus This of voltage is equal to or higher than the bus voltage threshold), it indicates that the photovoltaic power generation inverter is in an operating state where it is necessary to reduce the output power. The control circuit reduces the duty cycle of each switch within the inverter circuit to further reduce the output power of the inverter circuit, avoiding damage to the elements within the photovoltaic power generation inverter due to overheating, and further improving the safety of power supply.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying out the Invention

[0033] In the technical field of power electronics, an inverter circuit in a photovoltaic power generation inverter is usually used to convert DC energy into AC energy so that electrical energy can be transmitted between a power source and a load. For example, in the field of photovoltaic power generation power sources, a photovoltaic power generation inverter converts the DC energy output by a DC power source (for example, a photovoltaic power generation panel) into AC energy and provides it for use by a load or a power transmission grid. Generally, a control circuit (for example, an MPPT control circuit) in a photovoltaic power generation inverter controls the output current of the photovoltaic power generation panel (that is, the input current of the photovoltaic power generation inverter) based on the output voltage of the photovoltaic power generation panel (that is, the input voltage of the photovoltaic power generation inverter) so that the photovoltaic power generation panel outputs electrical energy to the load at the maximum power. In actual applications, a photovoltaic power generation inverter usually uses a plurality of voltage conversion circuits to convert the DC voltage provided by each group of photovoltaic power generation panels into a DC bus voltage (for example, boost the voltage of each group of photovoltaic power generation panels and convert it), and then uses an inverter circuit to convert DC energy into AC energy to adapt to the voltages of different loads. There are differences between groups of photovoltaic power generation panels (for example, different lengths or different light intensities). Therefore, the output voltage of the photovoltaic power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the ba This electricity s voltage (for example, boost the voltage of each group of photovoltaic power generation panels and convert it), and then uses an inverter circuit to convert DC energy into AC energy to adapt to the voltages of different loads. There are differences between groups of photovoltaic power generation panels (for example, different lengths or different light intensities). Therefore, the output voltage of the photovoltaic power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the ba This electricityWhen the difference from the voltage is excessively large, usually the input current in the voltage conversion circuit is high. As a result, due to overvoltage, overcurrent, or overheating, a failure or damage is caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit. Therefore, when the voltage conversion circuit operates, it is necessary to control the input power (or parameters such as the input current, for example) of the voltage conversion circuit so as to ensure the power supply safety of each element in the solar power generation inverter.

[0034] This application provides a solar power generation inverter and a power control method. When the input current of the target voltage conversion circuit is equal to or greater than the current threshold value of the target voltage conversion circuit, the duty cycle of the switch can be adjusted via a control circuit so as to reduce the input power of the voltage conversion circuit, thereby improving the stability and power supply efficiency of the solar power generation inverter while ensuring the safety of power supply. The structure is simple, the method is simple, and the applicability is high.

[0035] The solar power generation inverter provided in this application is applicable to a plurality of application fields, such as, for example, the field of new energy power generation, the field of conventional peak load adjustment and frequency adjustment for power generation, the field of power supply to important equipment, and the field of new energy vehicles. This can be specifically determined based on the actual application scenario and is not limited here. The solar power generation inverter provided in this application is applicable to different power supply systems, such as, for example, an energy storage system, an uninterruptible power supply system, and a motor drive system. This can be specifically determined based on the actual application scenario and is not limited here. The solar power generation inverter provided in this application can be adapted to different application scenarios, such as, for example, an application scenario of controlling an inverter in a photovoltaic power supply environment, an application scenario of controlling an inverter in a new energy power supply environment, or other application scenarios. Hereinafter, for the sake of illustration, an application scenario of controlling a solar power generation inverter in a photovoltaic power supply environment will be used as an example, and the details will not be described again below.

[0036] Please refer to FIG. 1. FIG. 1 is a schematic diagram of an application scenario of a solar power generation inverter according to an embodiment of this application. In a solar power generation system based on photovoltaic power supply, as shown in FIG. 1, the solar power generation system includes a solar power generation inverter 1, a power source 2 including a plurality of groups of solar power generation panels (for example, solar power generation panel a to solar power generation panel n), and a load 3. The power source 2 can be connected to the load 3 via the solar power generation inverter 1. In some realizable implementations, the solar power generation inverter 1 can convert the DC energy supplied by the power source 2 including a plurality of groups of solar power generation panels into AC energy and provide the AC energy to the load. It can be understood that the power source 2 provided in this application is applicable to application scenarios where power is supplied to various types of equipment, for example, it is applicable to application scenarios where power is supplied to base station equipment in remote areas without or with poor mains supply, or to household equipment (such as refrigerators or air conditioners, etc.). This can be specifically determined based on the actual application scenario and is not limited here. It can be further understood that the load 3 in FIG. 2 may include a power grid. The power grid here may include utilization equipment and power transmission equipment such as, for example, power transmission lines, power substations, communication base stations, or household equipment. Here, the solar power generation inverter 1 includes an inverter circuit 11 and a plurality of voltage conversion circuits (for example, voltage conversion circuit a to voltage conversion circuit n). Each group of solar power generation panels can be connected to the inverter circuit 11 via one corresponding voltage conversion circuit. The voltage conversion circuit converts the DC voltage provided by the solar power generation panel into a voltage, and then can convert the DC energy into AC energy through the inverter circuit so that the AC voltage output by the solar power generation inverter can adapt to loads within a plurality of voltage ranges. This electricity

[0037] ​In one possible implementation, for details, please refer to FIG. 2 together. FIG. 2 is a schematic diagram of a layout scenario of a solar power generation panel according to an embodiment of this application. As shown in FIG. 2, the gray part is the position where the solar power generation panel is arranged (for example, the top of a house or a building). In an application scenario including a plurality of groups of solar power generation panels, there are differences between groups of solar power generation panels (for example, as shown by part (a), part (b), and part (c) of FIG. 2, the light intensities of the solar power generation panels arranged at the top are different, and as shown by part (d), part (e), and part (f) of FIG. 2, the lengths and shapes of the solar power generation panels arranged at the top are different). Therefore, when the difference between the output voltage of the solar power generation panel connected to the voltage conversion circuit (that is, the input voltage of the voltage conversion circuit) and the ba This electricity When the difference between the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high) may cause failure or damage to the elements in the voltage conversion circuit (for example, the switches in the voltage conversion circuit). Therefore, when the solar power generation inverter 1 operates, it is necessary to control the input power of the voltage conversion circuit to ensure the power supply safety of each element in the solar power generation inverter. Here, the solar power generation inverter 1 may further include a control circuit 13 and an acquisition circuit 12. The acquisition circuit 12 can detect the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, the ba This of bus voltage and / or current, the input voltage and / or output voltage of the inverter circuit 11, the input current and / or output current of the inverter circuit 11, and the temperature of the inverter circuit 11). Here, the control circuit 13 can determine the operating state of the solar power generation inverter based on the power supply parameters of the solar power generation inverter. Here, an example is used in which one (or more) voltage conversion circuits that need to be controlled by the control circuit 13 is the target voltage conversion circuit. The control circuit 13 compares the input voltage of the target voltage conversion circuit with the ba This ofAfter the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the control circuit 13 adjusts the duty cycle of the switch in the target voltage conversion circuit (e.g., reduces the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit so as to reduce the input power of the target voltage conversion circuit, in order to protect the operational safety of the voltage conversion circuit. Control This improves the stability and power supply efficiency of the photovoltaic inverter while ensuring the safety of the power supply. The structure is simple, the method is easy, and the applicability is high.

[0038] The following describes the photovoltaic inverter provided in this application and the working principle of the photovoltaic inverter by using an example with reference to FIGS.

[0039] Please refer to FIG. 3. FIG. 3 is a schematic diagram of a solar power inverter structure according to an embodiment of this application. As shown in FIG. 3, a solar power system includes a power supply, a solar power inverter, and a load. The solar power inverter includes an inverter circuit 101, multiple voltage conversion circuits, multiple acquisition circuits, and a control circuit 103. Each voltage conversion circuit may include at least one switch. Here, to simplify and clarify the legend connection, the accompanying drawings of this application show the connection and detection relationship of the multiple acquisition circuits and integrate the multiple acquisition circuits into an acquisition circuit module to explain the operation principle of the multiple acquisition circuits. As shown in FIG. 3, as an example, the multiple acquisition circuits are shown as acquisition circuit 102. In a specific implementation, the acquisition circuit in each drawing may be divided into multiple acquisition circuits for layout purposes. Details will not be described below. Here, one end of each voltage conversion circuit may be configured to be connected to each of multiple groups of solar power panels. The other end of each voltage conversion circuit may be connected to a buffer. This toIt can be configured to be connected in parallel and then connected to a load via the inverter circuit 101. The acquisition circuit 102 is connected to the control circuit 103 and can be configured to detect a plurality of voltage conversion circuits and a This of voltage or current. The control circuit 103 is connected to the switches in each voltage conversion circuit. Here, the acquisition circuit 102 can be configured to detect the input voltage and the This of voltage of the target voltage conversion circuit. The target voltage conversion circuit is any one or more of the plurality of voltage conversion circuits. Here, the control circuit 103 can adjust the current threshold of the target voltage conversion circuit based on the input voltage and the This of voltage of the target voltage conversion circuit. Here, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the control circuit 103 adjusts the duty cycle of the switch in the target voltage conversion circuit to reduce the current or input power of the target voltage conversion circuit, and turns on or off the switch in the target voltage conversion circuit Control so that it can be configured to do so.

[0040] In this application, the voltage conversion circuit can be various circuits having a voltage conversion function. In FIG. 3, for the sake of explanation, only an example where the voltage conversion circuit is a boost circuit is used. Here, the boost circuit can include a switch, an inductor, and a diode. One end of the inductor is connected to a power source (i.e., a solar power generation panel). The other end of the inductor is connected to the This to via a switch and a diode. In some application scenarios, the boost circuit is This toReusing bus capacitors connected in parallel can stabilize the output voltage of a boost circuit through the bus capacitors. When the switch of the boost circuit is turned on, the power supply charges the inductor, and the boost circuit supplies power to the inverter circuit 101 (and the load) via the bus capacitor, and the diode prevents the confluence of electrical energy in the bus capacitor. When the switch of the boost circuit is turned off, the power supply and the inductor charge the bus capacitor, and the boost circuit boosts the input voltage to the voltage of the output bus capacitor. It can be understood that, ignoring the voltage of the switch of the boost circuit, the input voltage Vin of the boost circuit, the output voltage Vout of the boost circuit, and the duty cycle N of the switch of the boost circuit satisfy Vin / Vout = 1 / (1 - N). Here, the acquisition circuit 102 can detect the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, the voltage and / or current, the input voltage and / or output voltage of the inverter circuit 101, the input current and / or output current of the inverter circuit 101, and the temperature of the inverter circuit 101). Furthermore, it can be understood that the control circuit 103 can determine the operating state of the solar power generation inverter based on the power supply parameters of the solar power generation inverter. Here, an example is used in which one (or more) voltage conversion circuits that need to be controlled by the control circuit 103 is the target voltage conversion circuit. The control circuit 103 compares the input voltage of the target voltage conversion circuit with the bus voltage. This of voltage and / or current, the input voltage and / or output voltage of the inverter circuit 101, the input current and / or output current of the inverter circuit 101, and the temperature of the inverter circuit 101) can be detected. Further, it can be understood that the control circuit 103 can determine the operating state of the solar power generation inverter based on the power supply parameters of the solar power generation inverter. Here, an example is used in which one (or more) voltage conversion circuits that need to be controlled by the control circuit 103 is the target voltage conversion circuit. The control circuit 103 compares the input voltage of the target voltage conversion circuit with the bus voltage. This ofBased on the voltage, the current threshold of the target voltage conversion circuit can be adjusted. For details, please refer to FIG. 4 together. FIG. 4 is a schematic diagram of the voltage - ampere characteristics of a photovoltaic panel according to an embodiment of this application. As shown in FIG. 4, after the current threshold of the target voltage conversion circuit is obtained, assuming that the output parameters (e.g., output current and output voltage) of a group of photovoltaic panels connected to the target voltage conversion circuit correspond to point B on the voltage - ampere characteristic curve of the group of photovoltaic panels in FIG. 4. When the output current Ib of the photovoltaic panel corresponding to point B (i.e., the input current of the target voltage conversion circuit) is less than the current threshold of the target voltage conversion circuit, in order to ensure the power supply efficiency of the system, the control circuit 103 (e.g., MPPT control circuit) in the photovoltaic inverter adjusts the duty cycle of the switch in the target voltage conversion circuit based on the output voltage of the photovoltaic panel (i.e., the input voltage of the photovoltaic inverter) so as to increase the output current of the photovoltaic panel to Ia corresponding to point A (i.e., increase the input current of the photovoltaic inverter to Ia), so that the photovoltaic panel outputs electrical energy at the maximum power (i.e., the power indicated by point A). Thus, the turn - on or turn - off of the switch in the target voltage conversion circuit can be Control performed. Still as shown in FIG. 4, when the output current Ib of the photovoltaic panel corresponding to point B (i.e., the input current of the target voltage conversion circuit) is greater than or equal to the current threshold of the target voltage conversion circuit, in order to ensure the operation safety of the voltage conversion circuit, the control circuit 103 reduces the input power of the target voltage conversion circuit (i.e., reduces the input power of the target voltage conversion circuit to the power indicated by point C) by reducing the output current of the photovoltaic panel to Ic corresponding to point C (i.e., reducing the input current of the photovoltaic inverter to Ic). To do this, the duty cycle of the switch in the target voltage conversion circuit is adjusted (e.g., reducing the duty cycle of the switch in the target voltage conversion circuit), so that the turn - on or turn - off of the switch in the target voltage conversion circuit can be Control performed.

[0041] According to this application, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the solar power generation inverter can adjust the duty cycle of the switch via the control circuit 103 to reduce the input power of the voltage conversion circuit, thereby improving the stability and power supply efficiency of the solar power generation inverter while ensuring the safety of power supply. The structure is simple, the method is easy, and the applicability is high.

[0042] In some possible implementations, the acquisition circuit 102 may be further configured to detect the temperature of the target voltage conversion circuit. The control circuit 103 may be further configured to, when the temperature of the target voltage conversion circuit is equal to or greater than the temperature threshold, the input voltage of the target voltage conversion circuit and the b This ofBased on the voltage, it can be configured to adjust the current threshold of the target voltage conversion circuit to a first current threshold. It can be understood that the control circuit 103 can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit 103 can determine the operating state of the target voltage conversion circuit in multiple ways, and further can determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit 103 needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage differences borne by the switches are the same, the input currents that the switches can withstand can be different. For details, please refer to FIG. 5 together. FIG. 5 is a schematic diagram of the current threshold curve of the voltage conversion circuit according to an embodiment of this application. As shown in FIG. 5, a solar power generation inverter or an external central control system can calculate the curve of the corresponding current threshold Ith when the switch bears different voltage differences D(V) in a specific operating temperature or a specific operating temperature range (for example, the first operating temperature range above the temperature threshold) during the operation process (or design process) of the voltage conversion circuit as curve 1. Also, the control circuit 103 can obtain the first current threshold based on the curve. For example, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or greater than the temperature threshold), the control circuit 103 can determine the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the b This ofBased on the difference from the voltage, the maximum input current (for example, the first current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Note that the value of the first current threshold can be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, based on the corresponding nominal current when switches of various models bear different voltage differences), or it can be determined based on the current threshold obtained by the solar power generation inverter in a manner such as acquisition, collection, reception, detection, or storage. The first current threshold can be specifically set based on the application scenario. It can be understood that the first current threshold here can be one current, or multiple discrete currents, or a current range including multiple discrete currents or continuous currents.

[0043] In this application, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold), if the input current of the switch in the target voltage conversion circuit is equal to or higher than the first current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit 103 reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit 103 does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the electrical energy transmission efficiency on the basis of ensuring safety.

[0044] In some realizable implementations, when the temperature of the target voltage conversion circuit is less than the temperature threshold, the control circuit 103 further... This ofBased on the voltage, it can be configured to adjust the current threshold of the target voltage conversion circuit to a second current threshold. The second current threshold is greater than or equal to the first current threshold. It can be understood that the control circuit 103 can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit 103 can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment and will be damaged with a high risk if it continues to operate). In this case, the control circuit 103 needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage difference borne by the switches is the same, the input currents that the switches can withstand can be different. As still shown in FIG. 5, in the operation process (or design process) of the voltage conversion circuit, when the switch bears different voltage differences D(V) at a specific operating temperature or a specific operating temperature range (for example, a second operating temperature range lower than the temperature threshold), the corresponding curve of the current threshold Ith can be calculated as curve 2 by the solar power generation inverter or an external central control system. Also, the control circuit 103 can obtain the second current threshold based on the curve. For example, when the operating temperature of the switch in the target voltage conversion circuit is low (for example, the temperature of the target voltage conversion circuit is less than the temperature threshold), the control circuit 103 determines the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the b This ofBased on the difference from the voltage, the maximum input current (for example, the second current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Here, the second current threshold is smaller than the first voltage threshold. Note that the value of the second current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold acquired by the solar power generation inverter by means such as acquisition, collection, reception, detection, or storage. The second current threshold can be specifically set based on the application scenario. It can be understood that the second current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents.

[0045] In this application, when the operating temperature of the switch in the target voltage conversion circuit is low (for example, the temperature of the target voltage conversion circuit is lower than the temperature threshold), if the input current of the switch in the target voltage conversion circuit is equal to or greater than the second current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit 103 reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit 103 does not completely cut off the input electrical energy of the target voltage conversion circuit. This ensures the electrical energy transmission efficiency on the basis of ensuring safety.

[0046] In some realizable implementations, the control circuit 103 further generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, and based on the switching modulation signal, the duty cycle of the switch in the target voltage conversion circuit is Adjustmentto turn on or off a switch in the target voltage conversion circuit Control can be configured. Here, the control circuit 103 (for example, a current adjustment loop (for example, a proportional adjustment circuit or a proportional integral adjustment circuit) and a drive control circuit 103, or another circuit having a current adjustment function and a drive control function) generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit, and adjusts the duty cycle of the switch in the target voltage conversion circuit Adjustment For example, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the control circuit 103 generates a reference value smaller than the current threshold based on the current threshold of the target voltage conversion circuit, and by using the input current of the target voltage conversion circuit as a variable to be adjusted, generates a switching modulation signal for adjusting the duty cycle of the switch in the target voltage conversion circuit based on the switching modulation signal, and can adjust the input current in the target voltage conversion circuit to be less than the current threshold of the target voltage conversion circuit (that is, the above-mentioned reference value). Here, the control circuit 103 Adjustment can generate a signal such as a wave as the switching modulation signal, or can generate a drive pulse signal as a switching modulation signal based on a PWM wave. Here, the switching modulation signal adjusts the duty cycle of the switch in the target voltage conversion circuit PWM and can further control the input current and / or input power of the target voltage conversion circuit. For example, the control circuit 103 can reduce the duty cycle of the switch in the target voltage conversion circuit, reduce the input current of the target voltage conversion circuit, and reduce the input power of the target voltage conversion circuit. It can be understood that the control circuit 103 provided in this application may use a wave as the switching modulation signal, and another PWM wave (for example, Adjustment wave, DPWM wave, or SPWM wave, or THIPWM wave, or CBPWMWaves may be used, or drive pulse signals generated based on these PWM waves as switching modulation signals may be used. The applicable range is wide and the control effect is good.

[0047] In some realizable implementations, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit, the control circuit 103 further adjusts the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power, and turns on or off the switch in the target voltage conversion circuit. ControlIt can be configured to do so. Referring to FIG. 4 again. After the current threshold of the target voltage conversion circuit is obtained, assume that the output parameters (e.g., output current and output voltage) of the group of solar power generation panels connected to the target voltage conversion circuit correspond to point B on the volt-ampere characteristic curve of the group of solar power generation panels in FIG. 4. When the output current Ib of the solar power generation panel corresponding to point B (i.e., the input current of the target voltage conversion circuit) is less than the current threshold of the target voltage conversion circuit (e.g., the third current threshold), the target voltage conversion circuit can be considered to be in an operating state where it is not necessary to reduce the input power (in other words, the switch in the target voltage conversion circuit is operating in a safe environment with a low risk of damage). In this case, the control circuit 103 can adjust the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (e.g., the solar power generation panel connected to the target voltage conversion circuit operates at the maximum power point). Here, the value of the third current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., determined based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold obtained by the solar power generation inverter by means such as acquisition, collection, reception, detection, or storage. For example, the solar power generation inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences in a specific operating temperature or a specific operating temperature range (e.g., the first operating temperature range above the temperature threshold, or the second operating temperature range below the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Also, the control circuit 103 can obtain the third current threshold based on the curve. The third current threshold can be specifically set based on the application scenario. It can be understood that the third current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents. For example, in the first operating temperature range above the temperature threshold, the third current threshold can be set to be less than or equal to the first current threshold.In another example, in a second operating temperature range below the temperature threshold, the third current threshold may be less than or equal to the second current threshold.

[0048] It can be understood that when the third voltage threshold is smaller than the first current threshold (or the second current threshold), the photovoltaic inverter can avoid repeatedly decreasing or increasing the input power of the target voltage conversion circuit via the control circuit 103 when the input current of the target voltage conversion circuit does not stably become smaller than the first current threshold (or the second current threshold). In other words, when the third voltage threshold is less than the first current threshold (or the second current threshold), after the input current of the target voltage conversion circuit has stabilized (for example, stably less than the third current threshold), the target voltage conversion circuit of the photovoltaic inverter may be in an operating state where it is not necessary to reduce the input power (or, in other words, the switches in the target voltage conversion circuit are operating in a safe environment with a low risk of damage). In this case, the control circuit 103 can adjust the duty cycle of the switches in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the photovoltaic panel connected to the target voltage conversion circuit operates at the maximum power point). This improves the power supply efficiency.

[0049] In some possible implementations, the inverter circuit may include switches (for example, a multilevel inverter circuit and its topology circuit). Refer to FIG. 6. FIG. 6 is a schematic diagram of another structure of a photovoltaic inverter according to an embodiment of this application. As shown in FIG. 6, the inverter circuit 201 includes two capacitors connected in series, four switches connected in series, and two diodes connected in anti-parallel. The connection and operating principles of the voltage conversion circuit, the acquisition circuit 202, and the control circuit 203 in FIG. 3 are the same as those of the voltage conversion circuit, the acquisition circuit 102, and the control circuit 103 in FIG. 3, and details will not be described again here. Here, the control circuit 203 further includes a b This ofWhen the voltage is equal to or higher than the bus voltage threshold, the duty cycle of the switches in the inverter circuit 201 is adjusted to reduce the output power of the inverter circuit 201, and the switches in the inverter circuit 201 are turned on or off. Control It can be configured to do so. It can be understood that the control circuit 203 can determine the operating state of the solar power generation inverter in a plurality of ways, and can further determine whether it is necessary to control the output power (or output current) of the solar power generation inverter (for example, the inverter circuit 201). For example, when This of the voltage is equal to or higher than the bus voltage threshold, the inverter circuit 201 is in an operating state where it is necessary to reduce the output power (or in other words, each element in the solar power generation inverter is operating in a harsh environment, and if it continues to operate, it will be damaged at a high risk). In this case, the control circuit 203 needs to reduce the output current and / or output power of the inverter circuit 201. It can be understood that the bus voltage threshold here may be a single voltage, or a plurality of discrete voltages, or a voltage range including a plurality of discrete voltages or continuous voltages.

[0050] In this application, when This of the voltage is high (for example, Bus of the voltage is equal to or higher than the bus voltage threshold), it indicates that the solar power generation inverter is in an operating state where it is necessary to reduce the output power. The control circuit 203 can reduce the duty cycle of each switch in the inverter circuit 201 and further reduce the output power of the inverter circuit 201 to avoid damage to the elements in the solar power generation inverter due to overheating and further improve the safety of power supply.

[0051] This application further provides a solar power generation system. For details, please refer to FIG. 7 together. FIG. 7 is a schematic diagram of the structure of a solar power generation system according to an embodiment of this application. As shown in FIG. 7, the solar power generation system may include a power source and a solar power generation inverter. The solar power generation inverter here is applicable to the solar power generation inverter shown in FIGS. 1-6. In FIG. 7, only the solar power generation inverter shown in FIG. 3 is used as an example for explanation. It can be understood that the connection mode and operating principle of the inverter circuit 301, voltage conversion circuit, acquisition circuit 302, and control circuit 303 in FIG. 7 are the same as those of the inverter circuit 101, voltage conversion circuit, acquisition circuit 102, and control circuit 103 in FIG. 3. Details will not be described here again. In the solar power generation system shown in FIG. 7, the load here can be a power grid. The solar power generation system may further include a grid connection and off-grid wiring device 305. The solar power generation inverter can supply power to utilization devices or power transmission devices in the power grid, such as power transmission lines, power transmission stations, batteries, communication base stations, or household appliances, through the grid connection and off-grid wiring device 305.

[0052] In this application, the configuration modes of functional modules in the solar power generation inverter, solar power generation system, and solar power generation power system are diversified, flexible, and adaptable to different power supply environments. Therefore, the diversity of application scenarios of the solar power generation system is improved, and the adaptability of the solar power generation system is enhanced. In addition, according to any of the solar power generation systems or solar power generation inverters shown in FIGS. 1-7, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the control circuit can adjust the duty cycle of the switch so as to reduce the input power of the voltage conversion circuit, thereby improving the stability of the solar power generation inverter and the power supply efficiency while ensuring the safety of power supply. The structure is simple, the method is simple, and the applicability is high. For the sake of easy explanation, hereinafter, the power control method provided in the embodiment of this application will be described by taking the structure of the solar power generation inverter shown in FIG. 3 as an example.

[0053] Please refer to FIG. 8. FIG. 8 is a schematic flowchart of the power control method according to this application. The control method provided in this application is applicable to a photovoltaic power generation system or a photovoltaic power generation inverter. The photovoltaic power generation system here may include an inverter circuit and a plurality of voltage conversion circuits. One end of each voltage conversion circuit is configured to be connected to a photovoltaic power generation panel. The other end of each voltage conversion circuit is configured to be connected in parallel and then connected to a load through the inverter circuit. Here, the photovoltaic power generation system and the photovoltaic power generation inverter also include, but are not limited to, any of the photovoltaic power generation systems shown in FIGS. 1-7 or the photovoltaic power generation inverter in the photovoltaic power generation system. As shown in FIG. 8, the power control method provided in this application includes the following steps. This to Please refer to FIG. 8. FIG. 8 is a schematic flowchart of the power control method according to this application. The control method provided in this application is applicable to a photovoltaic power generation system or a photovoltaic power generation inverter. The photovoltaic power generation system here may include an inverter circuit and a plurality of voltage conversion circuits. One end of each voltage conversion circuit is configured to be connected to a photovoltaic power generation panel. The other end of each voltage conversion circuit is configured to be connected in parallel and then connected to a load through the inverter circuit. Here, the photovoltaic power generation system and the photovoltaic power generation inverter also include, but are not limited to, any of the photovoltaic power generation systems shown in FIGS. 1-7 or the photovoltaic power generation inverter in the photovoltaic power generation system. As shown in FIG. 8, the power control method provided in this application includes the following steps.

[0054] S701: Detect the input voltage, input current of the target voltage conversion circuit, and the voltage of the bus. This of Detect the input voltage, input current of the target voltage conversion circuit, and the voltage of the bus.

[0055] S702: Adjust the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus. This of Adjust the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus.

[0056] S703: When the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, adjust the duty cycle of the switch in the target voltage conversion circuit to turn on or off the switch in the target voltage conversion circuit so as to reduce the current or input power of the target voltage conversion circuit. Control Turn on or off the switch in the target voltage conversion circuit.

[0057] In this application, a solar power generation panel can be connected to a load as a DC power source via a solar power generation inverter. The solar power generation inverter can convert the DC energy provided by the solar power generation panel into AC energy and supply the AC energy to the load. Here, the solar power inverter may include an inverter circuit and a plurality of voltage conversion circuits. The DC power source may include a plurality of groups of solar power generation panels (each group of solar power generation panels may include one solar power generation panel or a plurality of solar power generation panels). Each group of solar power generation panels can be connected to the inverter circuit via one corresponding voltage conversion circuit. The voltage conversion circuit converts the DC voltage provided by the solar power generation panel into a voltage, and then can convert the DC energy into AC energy through the inverter circuit so that the AC voltage output by the solar power generation inverter can be adapted to loads within a plurality of voltage ranges. In an application scenario including a plurality of groups of solar power generation panels, there are differences between the groups of solar power generation panels (for example, different lengths, different shapes, or different light intensities). Therefore, when the difference between the output voltage of the solar power generation panel (i.e., the input voltage of the voltage conversion circuit) connected to (one or some of) the voltage conversion circuits and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high), failures or damages may be caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit. Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit acquires the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This electricity When the difference between the output voltage of the solar power generation panel (i.e., the input voltage of the voltage conversion circuit) connected to (one or some of) the voltage conversion circuits and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high), failures or damages may be caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit. Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit acquires the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This electricity When the difference between the output voltage of the solar power generation panel (i.e., the input voltage of the voltage conversion circuit) connected to (one or some of) the voltage conversion circuits and the voltage is excessively large, usually, the input current in the voltage conversion circuit is high. As a result, due to overvoltage (the voltage difference is excessively large), overcurrent (the current is excessively high), or overheating (the temperature is excessively high), failures or damages may be caused to the elements (for example, the switches in the voltage conversion circuit) within the voltage conversion circuit. Here, the solar power generation inverter may further include a control circuit and an acquisition circuit. The acquisition circuit acquires the power supply parameters of the solar power generation inverter (for example, the input voltage and / or output voltage of the voltage conversion circuit, the input current and / or output current of the voltage conversion circuit, the temperature of the voltage conversion circuit, This ofIt is possible to detect (voltage and / or current, the input voltage and / or output voltage of the inverter circuit, the input current and / or output current of the inverter circuit, and the temperature of the inverter circuit). Here, the control circuit can determine the operating state of the photovoltaic power generation inverter based on the power parameters of the photovoltaic power generation inverter. Here, an example is used in which one (or more) voltage conversion circuits that need to be controlled by the control circuit is the target voltage conversion circuit. The control circuit can adjust the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the This of voltage. After the current threshold of the target voltage conversion circuit is obtained, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, in order to protect the operating safety of the voltage conversion circuit, the control circuit can adjust the duty cycle of the switch in the target voltage conversion circuit (for example, reduce the duty cycle of the switch in the target voltage conversion circuit) to turn on or off the switch in the target voltage conversion circuit so as to reduce the current or input power of the target voltage conversion circuit. Control It is possible to do so.

[0058] According to this application, when the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the photovoltaic power generation inverter can adjust the duty cycle of the switch through the control circuit to reduce the input power of the voltage conversion circuit, thereby improving the stability of the photovoltaic power generation inverter and the power supply efficiency while ensuring the safety of the power supply. The structure is simple, the method is simple, and the applicability is high.

[0059] In some possible implementations, please refer to FIG. 9 together. FIG. 9 is another schematic flowchart of the power control method according to this application. As shown in FIG. 9, the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the This ofAfter executing the step S701 of detecting the voltage, the control circuit (or the solar power generation inverter) can determine the current threshold of the target voltage conversion circuit based on the input voltage and the input current of the target voltage conversion circuit. The power control method may further include the following steps.

[0060] S801: Detect the temperature of the target voltage conversion circuit.

[0061] S802: Determine whether the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold. If the determination result is positive (yes), step S803 is executed. If the determination result is negative (no), step S804 is executed.

[0062] It can be understood that the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to control the input power (or input current) of the target voltage conversion circuit. In other words, the control circuit can determine the operating state of the target voltage conversion circuit in a plurality of ways, and can further determine whether it is necessary to adjust the duty cycle of the switch in the target voltage conversion circuit. For example, when the input current of the target voltage conversion circuit is equal to or higher than the current threshold of the target voltage conversion circuit, the target voltage conversion circuit is in an operating state where it is necessary to reduce the input power (or, in other words, the switch in the target voltage conversion circuit is operating in a harsh environment, and if it continues to operate, it will be damaged at a high risk). In this case, the control circuit needs to reduce the input current and / or input power of the target voltage conversion circuit. Here, when the operating temperatures of the switches in the target voltage conversion circuit are different, even if the voltage difference borne by the switches is the same, the input currents that the switches can withstand may be different.

[0063] S803: Based on the input voltage of the target voltage conversion circuit and the This of voltage, adjust the current threshold of the target voltage conversion circuit to a first current threshold.

[0064] Here, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold), the control circuit calculates the voltage difference borne by the switch in the target voltage conversion circuit (for example, the difference between the input voltage of the target voltage conversion circuit and the This of voltage) to determine the maximum input current (for example, the first current threshold) that the switch in the target voltage conversion circuit can withstand. Note that the value of the first current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, determined based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold obtained by the solar power generation inverter by means such as acquisition, collection, reception, detection, or storage. For example, in the operation process (or design process) of the voltage conversion circuit, the solar power generation inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (for example, the first operating temperature range equal to or higher than the temperature threshold). Also, based on the curve, the control circuit can obtain the first current threshold. The first current threshold can be specifically set based on the application scenario. It can be understood that the first current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents.

[0065] In this application, when the operating temperature of the switch in the target voltage conversion circuit is high (for example, the temperature of the target voltage conversion circuit is equal to or higher than the temperature threshold), and when the input current of the switch in the target voltage conversion circuit is equal to or higher than the first current threshold, this indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and can improve the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This ensures the electrical energy transmission efficiency on the basis of ensuring safety.

[0066] S804: Based on the input voltage of the target voltage conversion circuit and the This of voltage, adjust the current threshold of the target voltage conversion circuit to a second current threshold.

[0067] Here, when the operating temperature of the switch in the target voltage conversion circuit is low (for example, the temperature of the target voltage conversion circuit is lower than the temperature threshold), the control circuit determines the voltage difference borne by the switch in the target voltage conversion circuit (for example, the input voltage of the target voltage conversion circuit and the This ofBased on the difference between the voltage (e.g., the difference between the input voltage and the target voltage), the maximum input current (e.g., the second current threshold) that the switch in the target voltage conversion circuit can withstand can be determined. Here, the second current threshold is smaller than the first voltage threshold. Note that the value of the second current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (e.g., based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold acquired by the solar power generation inverter in a manner such as acquisition, collection, reception, detection, or storage. For example, the solar power generation inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences at a specific operating temperature or within a specific operating temperature range (e.g., the second operating temperature range lower than the temperature threshold) during the operation process (or design process) of the voltage conversion circuit. Further, the control circuit can acquire the second current threshold based on the curve. The second current threshold can be specifically set based on the application scenario. It can be understood that the second current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents.

[0068] In this application, when the operating temperature of the switch in the target voltage conversion circuit is low (e.g., the temperature of the target voltage conversion circuit is lower than the temperature threshold) and the input current of the switch in the target voltage conversion circuit is equal to or greater than the second current threshold, it indicates that the target voltage conversion circuit is in an operating state where it is necessary to adjust the target voltage conversion circuit. The control circuit reduces the duty cycle of the switch in the target voltage conversion circuit so as to further reduce the input power of the target voltage conversion circuit, avoid damage to the elements in the target voltage conversion circuit due to overheating, and improve the safety of the target voltage conversion circuit. Also, the control circuit does not completely cut off the input electrical energy of the target voltage conversion circuit. This is to ensure the electrical energy transmission efficiency on the basis of ensuring safety.

[0069] When the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, the duty cycle of the switch in the target voltage conversion circuit is adjusted to reduce the current or input power of the target voltage conversion circuit, so as to turn on or off the switch in the target voltage conversion circuit. Control Do it.

[0070] In some possible implementations, when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, a switching modulation signal is generated based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit, and the duty cycle of the switch in the target voltage conversion circuit is controlled based on the switching modulation signal to turn on or off the switch in the target voltage conversion circuit. Control Do it.

[0071] Here, a control circuit (for example, a current adjustment loop (for example, a proportional adjustment circuit or a proportional integral adjustment circuit) and a drive control circuit, or other circuits having a current adjustment function and a drive control function) generates a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit, and the duty cycle of the switch in the target voltage conversion circuit can be Adjustment obtained. For example, the control circuit can generate a signal such as a PWM wave as the switching modulation signal, or can generate a drive pulse signal as the switching modulation signal based on the PWM wave. Here, the switching modulation signal can adjust the duty cycle of the switch in the target voltage conversion circuit, and further control the input current and / or input power of the target voltage conversion circuit. For example, the control circuit can reduce the duty cycle of the switch in the target voltage conversion circuit to reduce the input current of the target voltage conversion circuit and reduce the input power of the target voltage conversion circuit. It can be understood that the control circuit provided in this application can use a Adjustment wave as the switching modulation signal, or another PWM wave (for example, DPWM wave) as the switching modulation signal. SPWMWave, THIPWM wave, or CBPWM waves may be used, or a drive pulse signal generated based on these PWM waves as a switching modulation signal may be used. The applicable range is wide and the control effect is good.

[0072] In some realizable implementations, after step S702 or S803 or S804 of adjusting the current threshold of the target voltage conversion circuit based on the input voltage and the This of bias voltage of the target voltage conversion circuit is executed, the method further includes when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit, adjusting the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power, and turning on or off the switch in the target voltage conversion circuit Control which may include.

[0073] Here, when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit (for example, the third current threshold), the target voltage conversion circuit can be considered to be in an operating state where it is not necessary to reduce the input power (in other words, the switch in the target voltage conversion circuit is operating in a safe environment with a low risk of damage). In this case, the control circuit can adjust the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the photovoltaic panel connected to the target voltage conversion circuit operates at the maximum power point). Here, the value of the third current threshold may be determined based on the maximum input current of the switch in the target voltage conversion circuit (for example, determined based on the corresponding nominal current when switches of various models bear different voltage differences), or may be determined based on the current threshold acquired by the photovoltaic inverter by means such as acquisition, collection, reception, detection, or storage. For example, in the operation process (or design process) of the voltage conversion circuit, the photovoltaic inverter or an external central control system can calculate the curve of the corresponding current threshold when the switch bears different voltage differences in a specific operating temperature or a specific operating temperature range (for example, the first operating temperature range above the temperature threshold, or the second operating temperature range below the temperature threshold). Also, based on this curve, the control circuit can acquire the third current threshold. The third current threshold can be specifically set based on the application scenario. It can be understood that the third current threshold here may be one current, or a plurality of discrete currents, or a current range including a plurality of discrete currents or continuous currents. For example, in the first operating temperature range above the temperature threshold, the third current threshold can be set to be less than or equal to the first current threshold. In another example, in the second operating temperature range below the temperature threshold, the third current threshold can be set to be less than or equal to the second current threshold. When the third voltage threshold is smaller than the first current threshold (or the second current threshold), the photovoltaic inverter can avoid repeatedly decreasing or increasing the input power of the target voltage conversion circuit via the control circuit when the input current of the target voltage conversion circuit does not stably become less than the first current threshold (or the second current threshold).In other words, when the third voltage threshold is less than the first current threshold (or the second current threshold), after the input current of the target voltage conversion circuit has stabilized (for example, stably less than the third current threshold), the target voltage conversion circuit of the solar power generation inverter may be in an operating state where it is not necessary to reduce the input power (or, in other words, the switches in the target voltage conversion circuit are operating in a safe environment with a low risk of damage). In this case, the control circuit may adjust the duty cycle of the switches in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power (for example, the solar power generation panel connected to the target voltage conversion circuit operates at the maximum power point). This improves the power supply efficiency.

[0074] In some possible implementations, after the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the This of bus voltage are detected, the method may further bus This of When the bus voltage is greater than or equal to the bus voltage threshold, adjust the duty cycle of the switches in the inverter circuit to turn on or off the switches in the inverter circuit so as to reduce the output power of the inverter circuit. Control This may be included.

[0075] It can be understood that the control circuit can determine the operating state of the solar power generation inverter in multiple ways, and can further determine whether it is necessary to control the output power (or output current) of the solar power generation inverter (for example, the inverter circuit). For example, bus This ofWhen the voltage is equal to or higher than the bus voltage threshold, the inverter circuit may be in an operating state where it is necessary to reduce the output power (or, in other words, each element in the solar power generation inverter is operating in a harsh environment and would be at high risk of damage if it continues to operate). In this case, the control circuit needs to reduce the output current and / or output power of the inverter circuit. It can be understood that the bus voltage threshold here may be a single voltage, or a plurality of discrete voltages, or a voltage range including a plurality of discrete voltages or continuous voltages.

[0076] It can be understood that the b This of When the voltage is high (for example, the bus voltage is equal to or higher than the bus voltage threshold), it indicates that the solar power generation inverter is in an operating state where it is necessary to reduce the output power. The control circuit reduces the duty cycle of each switch in the inverter circuit to further reduce the output power of the inverter circuit, thereby avoiding damage to the elements in the solar power generation inverter due to overheating and further improving the safety of the power supply.

[0077] In this application, when the input current of the target voltage conversion circuit is equal to or higher than the current threshold of the target voltage conversion circuit, the solar power generation inverter can adjust the duty cycle of the switch via the control circuit to reduce the input power of the voltage conversion circuit, thereby improving the stability of the solar power generation inverter and the power supply efficiency while ensuring the safety of the power supply. The structure is simple, the method is easy, and the applicability is high.

[0078] The above description is only a specific implementation of the present invention and is not intended to limit the protection scope of the present invention. Any deformation or replacement that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention falls within the protection scope of the present invention. Therefore, the protection scope of the present invention shall follow the protection scope of the claims.

Claims

1. A photovoltaic power generation inverter, the photovoltaic power generation inverter having an inverter circuit, a plurality of voltage conversion circuits, a plurality of acquisition circuits, and a control circuit, one voltage conversion circuit having at least one switch, one end of each voltage conversion circuit being configured to be connected corresponding to each of a plurality of groups of photovoltaic power generation panels, the other end of each voltage conversion circuit being connected in parallel to a bus and then connected to a load via the inverter circuit, the plurality of acquisition circuits being connected to the control circuit, the control circuit being connected to the switch in each voltage conversion circuit, the plurality of acquisition circuits being configured to detect the input voltage of a target voltage conversion circuit, the input current of the target voltage conversion circuit, and the voltage of the bus, the target voltage conversion circuit being any one or more of the plurality of voltage conversion circuits, the control circuit being configured to adjust a current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus, the control circuit being configured to adjust a duty cycle of the switch in the target voltage conversion circuit to control turning on or off of the switch in the target voltage conversion circuit so as to reduce the current or input power of the target voltage conversion circuit when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, A photovoltaic power generation inverter.

2. The plurality of acquisition circuits are further configured to detect the temperature of the target voltage conversion circuit, the control circuit being further configured to adjust the current threshold of the target voltage conversion circuit to a first current threshold based on the input voltage of the target voltage conversion circuit and the voltage of the bus when the temperature of the target voltage conversion circuit is greater than or equal to a temperature threshold, The photovoltaic power generation inverter according to Claim 1.

3. The control circuit is further configured to adjust the current threshold of the target voltage conversion circuit to a second current threshold based on the input voltage of the target voltage conversion circuit and the voltage of the bus when the temperature of the target voltage conversion circuit is less than the temperature threshold, the second current threshold being greater than or equal to the first current threshold, The photovoltaic power generation inverter according to Claim 2.

4. The control circuit is further configured to generate a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit when the input current of the target voltage conversion circuit is greater than or equal to the current threshold of the target voltage conversion circuit, and to control the turn-on or turn-off of the switch in the target voltage conversion circuit by adjusting the duty cycle of the switch in the target voltage conversion circuit based on the switching modulation signal. The solar power generation inverter according to any one of claims 1 to 3.

5. The control circuit is further configured to control the turn-on or turn-off of the switch in the target voltage conversion circuit by adjusting the duty cycle of the switch in the target voltage conversion circuit so that the input power of the target voltage conversion circuit remains at the maximum target input power when the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit. The solar power generation inverter according to claim 4.

6. The inverter circuit has a switch, and the control circuit is further configured to control the turn-on or turn-off of the switch in the inverter circuit by adjusting the duty cycle of the switch in the inverter circuit so as to reduce the output power of the inverter circuit when the voltage of the bus is greater than or equal to a bus voltage threshold. The solar power generation inverter according to any one of claims 1 to 3.

7. A power control method applicable to a solar power generation system, wherein the solar power generation system includes an inverter circuit and a plurality of voltage conversion circuits, One end of each voltage conversion circuit is configured to be connected to a solar power generation panel, and the other end of each voltage conversion circuit is configured to be connected in parallel to a bus and then connected to a load through the inverter circuit. The method includes: Detecting the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the voltage of the bus, where the target voltage conversion circuit is any one or more of the plurality of voltage conversion circuits, Adjusting the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus. When the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, the duty cycle of the switch in the target voltage conversion circuit is adjusted to reduce the current or input power of the target voltage conversion circuit, thereby controlling the turn-on or turn-off of the switch in the target voltage conversion circuit. A control method having this.

8. Based on the input voltage of the target voltage conversion circuit and the voltage of the bus, adjusting the current threshold of the target voltage conversion circuit includes: Detecting the temperature of the target voltage conversion circuit; When the temperature of the target voltage conversion circuit is equal to or greater than the temperature threshold, based on the input voltage of the target voltage conversion circuit and the voltage of the bus, adjusting the current threshold of the target voltage conversion circuit to a first current threshold. The control method according to claim 7, having this.

9. After detecting the temperature of the target voltage conversion circuit, the method further includes: When the temperature of the target voltage conversion circuit is less than the temperature threshold, based on the input voltage of the target voltage conversion circuit and the voltage of the bus, adjusting the current threshold of the target voltage conversion circuit to a second current threshold, and the second current threshold is equal to or greater than the first current threshold. The control method according to claim 8, having this.

10. After adjusting the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus, the method further includes: When the input current of the target voltage conversion circuit is equal to or greater than the current threshold of the target voltage conversion circuit, generating a switching modulation signal based on the input current of the target voltage conversion circuit and the current threshold of the target voltage conversion circuit, and adjusting the duty cycle of the switch in the target voltage conversion circuit based on the switching modulation signal to control the turn-on or turn-off of the switch in the target voltage conversion circuit. The control method according to any one of claims 7 to 9, having this.

11. After adjusting the current threshold of the target voltage conversion circuit based on the input voltage of the target voltage conversion circuit and the voltage of the bus, the method further includes: When the input current of the target voltage conversion circuit is less than the current threshold of the target voltage conversion circuit, the duty cycle of the switch in the target voltage conversion circuit is adjusted to keep the input power of the target voltage conversion circuit at the maximum target input power, thereby controlling the turn-on or turn-off of the switch in the target voltage conversion circuit. The control method according to claim 10, comprising this.

12. The inverter circuit has a switch. After detecting the input voltage of the target voltage conversion circuit, the input current of the target voltage conversion circuit, and the voltage of the bus, the method further comprises: When the voltage of the bus is equal to or higher than the bus voltage threshold, the duty cycle of the switch in the inverter circuit is adjusted to reduce the output power of the inverter circuit, thereby controlling the turn-on or turn-off of the switch in the inverter circuit. The control method according to any one of claims 7 to 9, comprising this.

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