Auxiliary starting circuit and photovoltaic power generation system

Abstract

The embodiments of the present disclosure provide a power supply device and a photovoltaic power generation system. The power supply device includes: a power converter, configured to be coupled to a power source at its input side and to be coupled to a power supply target at its output side; and an auxiliary starting circuit, including an auxiliary load, the auxiliary starting circuit is coupled to the output side of the power converter, and is configured to couple the auxiliary load to the output side when the voltage on the output side reaches a first threshold, and to decouple the auxiliary load from the output side when the voltage on the output side reaches a second threshold higher than the first threshold. Through the scheme of the present disclosure, a weak power supply can be identified by an auxiliary starting circuit with a low withstand voltage level, thereby avoiding repeated starting of components such as a processor and repeated closing of electrical switches such as a main power relay due to insufficient power supply.

Description

Technical Field

[0001] The present disclosure mainly relates to the field of photovoltaic technology, and more specifically, to an auxiliary starting circuit and a photovoltaic power generation system including the auxiliary starting circuit. Background Art

[0002] In order to reduce carbon emissions and alleviate the impact of fossil energy on the environment, new energy industries such as photovoltaic power generation have received increasing attention and have achieved rapid development. Photovoltaic power generation technology uses the photovoltaic effect of semiconductor interfaces to directly convert light energy into electrical energy. Generally speaking, in addition to photovoltaic cells used to achieve the conversion of light energy into electrical energy, photovoltaic power generation systems may also include a series of electrical equipment, such as photovoltaic optimizers, electrical switches, power modules, etc., to help output the electrical energy generated by photovoltaic cells to subsequent systems such as power grids and busbars.

[0003] Furthermore, in order to control and drive the above-mentioned electrical equipment, it is necessary to provide corresponding control devices. Usually, the power from photovoltaic cells can be used to power these control devices. However, the output power of photovoltaic cells is affected by many factors such as light intensity, obstructions, temperature, etc., so the output power may be insufficient or even difficult to support the power demand of the control device, which will have an adverse effect on the control device and other parts of the photovoltaic power generation system. For example, when the output power of the photovoltaic cell is insufficient, it may cause the processor in the control device to restart repeatedly, or cause electrical switches such as the main power relay to be repeatedly attracted, which seriously affects the life of the processor and the main power relay. Summary of the invention

[0004] In order to solve the above problems, embodiments of the present disclosure provide an auxiliary starting circuit and a photovoltaic power generation system.

[0005] In a first aspect of the present disclosure, a power supply device is provided, comprising: a power converter configured to be coupled to a power source at its input side and to be coupled to a power supply target at its output side; and an auxiliary starting circuit including an auxiliary load, the auxiliary starting circuit being coupled to the output side of the power converter and being configured to couple the auxiliary load to the output side when the voltage on the output side reaches a first threshold value, and to decouple the auxiliary load from the output side when the voltage on the output side reaches a second threshold value higher than the first threshold value.

[0006] In the embodiments of the present disclosure, the auxiliary load can be pre-cut on the output side of the power converter of the power supply device to determine whether the power source has insufficient output power, thereby avoiding repeated restarts of important components such as processors in the power supply target due to insufficient power supply. Since the auxiliary startup circuit is arranged on the output side of the power converter, the auxiliary startup circuit and its auxiliary load can be implemented with a lower withstand voltage level, which has the advantages of low cost, high safety and reliability.

[0007] In some implementations of the present disclosure, the power source includes a photovoltaic power source of a photovoltaic power generation system, and the power supply target includes a control and drive component of the photovoltaic power generation system. In this implementation, the photovoltaic power source in the photovoltaic power generation system may be a weak power source with insufficient power supply due to many factors such as insufficient light. The auxiliary startup circuit can help identify whether the photovoltaic power source in the photovoltaic power generation system is a weak power source, thereby avoiding repeated restarts of the processor in the control and drive component.

[0008] In some implementations of the present disclosure, the auxiliary startup circuit is also coupled to the control and drive component, and is also configured to couple the auxiliary load to the output side based on a first voltage signal from the control and drive component, and to decouple the auxiliary load from the output side based on a second voltage signal from the control and drive component, the first voltage signal indicating that the processor in the control and drive component has completed initialization, and the second voltage signal indicating that the output voltage of the photovoltaic power source exceeds a third threshold. In this implementation, after the processor in the control and drive component is started and initialized, the auxiliary load can be switched on for the second time to determine whether the output power of the photovoltaic power source can support the control and drive component to control and drive the power module, and whether the electrical switch can be turned on, thereby avoiding repeated closure of the electrical switch due to insufficient power supply.

[0009] In some implementations of the present disclosure, the auxiliary startup circuit includes: at least one load branch, each load branch includes an auxiliary load and a switching switch connected in series, and is coupled to the output side of the power converter; and a first branch coupled to the control end of the switching switch and the output side of the power converter, the first branch being configured to turn on the switching switch based on the output voltage of the output side exceeding a first threshold, and to turn off the switching switch based on the output voltage of the output side exceeding a second threshold. In this implementation, the first switching of the auxiliary load can be implemented by using the load branch with the switching switch and the first branch for controlling the switching switch, which has the advantages of being simple and reliable.

[0010] In some implementations of the present disclosure, the auxiliary startup circuit further includes: a second branch coupled to the control and drive component and including a plurality of resistor elements and at least one switch device, the second branch being configured to turn on the switching switch via the first branch based on a first voltage signal from the control and drive component, and to turn off the switching switch via the first branch based on a second voltage signal from the control and drive component. In this implementation, the second switching of the auxiliary load is realized by using the second branch coupled to the control and drive component, which has the advantages of being simple and reliable.

[0011] In some implementations of the present disclosure, the first branch includes: a first biasing unit, including at least one resistor element coupled between the control end of the switching switch and the output side of the power converter, so that the switching switch is turned on when the output voltage of the output side exceeds a first threshold; and a second biasing unit, including multiple resistor elements and at least one switch device coupled between the control end of the switching switch and the output side of the power converter, so that the switching switch is turned off when the output voltage of the output side exceeds a second threshold. In this implementation, the switching switch is turned on and off respectively by setting two different biasing units.

[0012] In some implementations of the present disclosure, the power converter includes a plurality of output ports located at the output side, and the load branch is configured to be coupled to one of the plurality of output ports, the output voltage of the output port being higher than the output voltages of the other output ports. In such an implementation, the auxiliary load can be more easily obtained and at a lower cost.

[0013] In some implementations of the present disclosure, the second threshold is lower than a voltage corresponding to a startup voltage of a processor in the control and drive assembly. In such an implementation, repeated startup of the processor in the control and drive assembly during the process of identifying a weak power supply can be completely avoided, thereby protecting a processor such as a DSP.

[0014] In some implementations of the present disclosure, at least one load branch includes two load branches connected in parallel. In such implementations, the auxiliary load can adopt a higher power level and the current pressure of switching devices such as bipolar transistors can be reduced.

[0015] In a second aspect of the present disclosure, a photovoltaic power generation system is provided, which includes: a photovoltaic power source and a main power circuit; a control and drive component configured to control the main power circuit; and a power supply device according to the first aspect, configured to receive power from the photovoltaic power source and output power to the control and drive component.

[0016] In some implementations of the present disclosure, the main power circuit includes a power module and an electrical switch connected in series and coupled between a photovoltaic power source and a system load, and the control and drive component is configured to send a signal for turning on the electrical switch after sending a voltage signal to couple an auxiliary load of an auxiliary startup circuit to an output side of a power converter and decouple the auxiliary load from the output side.

[0017] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0019] Figure 1 A schematic block diagram of a photovoltaic power generation system according to an embodiment of the present disclosure is shown.

[0020] Figure 2 A schematic block diagram of a photovoltaic power generation system according to an alternative embodiment of the present disclosure is shown.

[0021] Figure 3 A schematic circuit diagram of a power supply device and some peripheral devices thereof according to an embodiment of the present disclosure is shown.

[0022] Figure 4 A schematic circuit diagram of an auxiliary startup circuit according to an alternative embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0023] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0024] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0025] The embodiments of the present disclosure propose an improved power supply scheme for the control and drive components in a photovoltaic power generation system. In a power supply device for powering the control and drive components, by setting an auxiliary starting circuit on the output side of a power converter, an auxiliary load can be switched in advance to determine whether the photovoltaic power source has a poor load capacity due to insufficient output power, so as to reduce or eliminate the situation where the processor in the control and drive components repeatedly restarts due to insufficient output power. Since the auxiliary starting circuit is set on the output side of the power converter, the auxiliary starting circuit and its auxiliary load do not need to have a very high withstand voltage level.

[0026] Figure 1 A schematic block diagram of a photovoltaic power generation system 1000 according to an embodiment of the present disclosure is shown. The photovoltaic power generation system 1000 includes a photovoltaic power source 100 and a main power circuit 200. As an example, the photovoltaic power source 100 may include a photovoltaic cell, for example, a photovoltaic string formed by connecting photovoltaic cells in series and / or in parallel to receive light energy and output electrical energy to the outside. The main power circuit 200 may perform appropriate operations on the output of the photovoltaic power source 100 to provide it to the subsequent system, and these operations include but are not limited to voltage regulation, boosting, bucking, inversion, maximum power point tracking, etc. In some embodiments, the main power circuit 200 includes a power module 210 and an electrical switch 220, and the power module 210 and the electrical switch 220 are coupled between the photovoltaic power source 100 and the system load 2000. By closing or opening the electrical switch 220, the photovoltaic power source 100 can be electrically connected to the power module 210, or they can be electrically disconnected. As an example, the power module 210 can be a power converter including a power switching device, which realizes the required power conversion by turning on and off the power switching device. The electrical switch 220 includes, but is not limited to, a contactor, a circuit breaker, an isolating switch, an air switch, a relay, and other appropriate types of electrical switches. For example, the power module 210 may be a DC-DC conversion circuit that implements a step-down function, and after the electrical switch 220 is closed, the power module 210 steps down the output voltage of the photovoltaic power source 100 and outputs it to the bus 600. Alternatively, the power module 210 may also be a DC-AC conversion circuit that implements an inverter function, and after the electrical switch 220 is closed, it may be used to convert the DC voltage output by the photovoltaic power source 100 into an AC voltage, and output it to the subsequent AC power grid. However, it is understood that the implementation of the main power circuit 200 is not limited thereto, and may include any appropriate circuits and devices required to provide the power generated by the photovoltaic power source 100 to the subsequent system.

[0027] The photovoltaic power generation system 1000 may include a control and drive assembly 300, which is configured to control the main power circuit 200. As an example, the control and drive assembly 300 may include components required for controlling and driving the power switch device to operate the power switch device in the power module 210. In addition, the control and drive assembly 300 may also be used to control the closing and opening of the electrical switch 220. For example, the control and drive assembly 300 may include a processor such as a DSP (Digital signal processor), and may include a driver, a driver chip and / or a driver circuit required to drive the power switch device and the electrical switch.

[0028] According to an embodiment of the present disclosure, the photovoltaic power generation system 1000 may include a power supply device 400, which is configured to receive power from the photovoltaic power source 100 and output power to the control and drive component 300. Specifically, the power supply device can use the power generated by the photovoltaic power source 100 to power the control and drive component 300 to meet the power consumption of active devices such as processors and drivers in the control and drive component 300. Figure 1 In the embodiment, the input of the power supply device 400 is directly coupled to the output of the photovoltaic power source 100, thereby directly obtaining power from the photovoltaic power source 100.

[0029] Figure 2 A schematic block diagram of a photovoltaic power generation system 1000 according to an alternative embodiment of the present disclosure is shown. Figure 2 The photovoltaic power generation system 1000 shown in FIG. Figure 1 The difference is that the power input of the power supply device 400 is coupled to the bus 600. In addition, the main power circuit 200 is also slightly different. Specifically, the main power circuit 200 is also provided with a parallel branch 230 coupled in parallel with the electrical switch 220, and the parallel branch 230 includes a resistor and a diode connected in series with each other. In this way, when the electrical switch 220 is not closed and the power switch device in the power module 210 is not driven, the power of the photovoltaic power source 100 can be provided to the bus 600 via the branch 230 and the power module 210 in a natural rectification state. Thus, the power supply device 400 can obtain power from the photovoltaic power source 100 from the bus 600. Figure 2 Other configurations of the photovoltaic power generation system 1000 are similar to Figure 1 , so I will not go into details.

[0030] Figure 3 4 shows a schematic circuit diagram of a power supply device 400 and some peripheral devices thereof according to an embodiment of the present disclosure. Figures 1 to 3The power supply device 400 is described in detail. According to an embodiment of the present disclosure, the power supply device 400 may include a power converter 410, which is configured to be coupled to a power source at its input side and to be coupled to a power supply target at its output side. The power source includes a photovoltaic power source 100 of a photovoltaic power generation system 1000, and the power supply target includes a control and drive component 300 of the photovoltaic power generation system 1000. It can be understood that the use scenario of the power supply device 400 is not limited thereto, but the power converter 410 of the power supply device 400 can be coupled to other power sources other than the photovoltaic power source 100 to receive power, and the power converter 410 can supply power to other power supply targets other than the control and drive component 300 of the photovoltaic system. As an example, the power converter 410 can be a DC-DC conversion circuit with an isolation transformer, such as a forward converter or a flyback converter, thereby receiving input power from the photovoltaic power source 100 as a power source on the primary side of the isolation transformer and outputting power to the control and drive component 300 as a power supply target on its secondary side. In addition, multiple secondary windings with different numbers of turns can be arranged on the secondary side of the isolation transformer to provide output voltages of various voltage levels, such as 12V, 4.5V, 3.3V, etc., so as to meet the different requirements of various components in the control and drive component 300 for the power supply voltage level.

[0031] According to an embodiment of the present disclosure, the power supply device 400 may further include an auxiliary starting circuit 420, which includes an auxiliary load RL. The auxiliary starting circuit 420 is coupled to the output side of the power converter 410, and is configured to couple the auxiliary load RL to the output side when the voltage of the output side reaches a first threshold, and to decouple the auxiliary load RL from the output side when the voltage of the output side reaches a second threshold higher than the first threshold. As an example, the auxiliary starting circuit 420 may be electrically connected to the output side of the power converter 410, for example, electrically connected to an output port of the output side, wherein the auxiliary load RL in the auxiliary starting circuit 420 is electrically connected to the output side in a disconnectable manner, for example, electrically connected to the associated output port. When the photovoltaic power source 100 receives light and starts to output electrical energy, the input side of the power converter 410 receives the power output by the photovoltaic power source 100 and starts to operate, whereby the voltage of the output side will gradually increase. The voltage on the output side of the power converter 410 reaching the predefined first threshold means that the power converter 410 receives power from the photovoltaic power source 100 and starts to output power to the control and drive component 300. When the voltage on the output side of the power converter 410 reaches the first threshold, the auxiliary start-up circuit 420 can connect the auxiliary load RL to the output side of the power converter 410 under the triggering or action of the voltage on the output side. The auxiliary load RL can be a resistor with a higher power level or multiple resistors connected in series and / or in parallel. Such resistors for the auxiliary load RL include but are not limited to cement resistors. At this time, although the control and drive component 300 receives input power, due to the low voltage, components such as processors in the control and drive component 300 have not yet started. After connecting the auxiliary load RL, if the voltage on the output side of the power converter 410 drops, or even power failure and restart occur, it means that the photovoltaic power supply 100 is a weak power supply, that is, the power of the photovoltaic power supply 100 is insufficient to support the startup and initialization of components such as processors in the control and drive component 300; and if the voltage on the output side of the power converter 410 continues to rise and reaches the second threshold, it means that the power of the photovoltaic power supply 100 is sufficient to support the startup and initialization of components such as processors. When triggered or acted upon by a voltage reaching the second threshold, the auxiliary startup circuit 420 will cut off the connection between the auxiliary load RL and the output side of the power converter 410. It can be seen that the connection of the auxiliary load RL can help identify whether the photovoltaic power source 100 is in a weak power state, which can effectively prevent important components such as a processor in the control and drive assembly 300 from losing power and repeatedly restarting during the startup process due to insufficient power of the photovoltaic power source 100, and prevent the processor from being repeatedly powered on due to incomplete initialization, causing the program to run away, which may affect the life of important components such as the processor and the reliability of system operation.

[0032] This arrangement is more advantageous in that the output voltage of the photovoltaic power source 100 may be as high as hundreds of volts, for example, as high as 400V or more, while the voltage on the output side of the power converter 410 used to power the control circuit such as the control and drive component 300 will be much lower, for example, it may be only a few volts or tens of volts. It can be seen that, compared with connecting the auxiliary starting circuit 420 to the output of the photovoltaic power source 100 to detect or test a weak power source, coupling the auxiliary starting circuit 420 to the output side of the power converter 410 significantly reduces the withstand voltage level of the auxiliary starting circuit 420, which helps to more flexibly select components in the auxiliary starting circuit 420, and is conducive to reducing the cost of the auxiliary starting circuit 420 and improving the reliability of the circuit as a whole.

[0033] In some embodiments of the present disclosure, the auxiliary startup circuit 420 includes a load branch 421 and a first branch 422, the load branch 421 includes an auxiliary load RL and a switching switch Q1 connected in series, and is coupled to the output side of the power converter 410, the first branch 422 is coupled to the control end of the switching switch Q1 and the output side of the power converter 410, and the first branch 422 is configured to turn on the switching switch Q1 based on the output voltage of the output side exceeding the first threshold, and turn off the switching switch Q1 based on the output voltage of the output side exceeding the second threshold. It can be understood that the load branch 421 can be a single branch or a plurality of branches connected in parallel, each of which includes an auxiliary load RL and a switching switch Q1. As an example only, the auxiliary load RL can include two cement resistors connected in parallel, and the switching switch Q1 can be a bipolar transistor.

[0034] As an example, when the output side voltage of the power converter 410 reaches the first threshold, the first branch 422 coupled to the output side of the power converter 410 triggers the switching switch Q1 to turn on, so that the auxiliary load RL is coupled to the ground through the turned-on switching switch Q1 and thus forms a loop. In some embodiments, the first branch 422 includes a first biasing unit 4221, and the first biasing unit 4221 includes resistors R1 and R2 coupled between the control end of the switching switch Q1 and the output side of the power converter 410, so that the switching switch Q1 is turned on when the output voltage of the output side exceeds the first threshold. For example, the resistors R1 and R2 can constitute a voltage divider, and thus the voltage of the output side is transmitted to the control end of the switching switch Q1, such as the base of the transistor Q1, by voltage division, so that the potential of the control end of the switching switch Q1 is increased, thereby turning on the switching switch Q1. Alternatively, the first biasing unit 4221 may also include a single resistor coupled between the control terminal of the switching switch Q1 and the output side of the power converter 410 , or include a voltage divider composed of more resistors, which can also achieve the turning-on operation of the switching switch Q1 .

[0035] As an example, when the output side voltage of the power converter 410 exceeds the second threshold, the first branch 422 coupled to the output side of the power converter 410 triggers the switching switch Q1 to turn off, which disconnects the auxiliary load RL from the ground, and thus the conduction loop of the load branch 421 is cut off. In some embodiments, the first branch 422 includes a second biasing unit 4222, which includes a plurality of resistor elements R3, R4, R5, R6, R7, R8 and at least one switching device Q2, Q3, Q4 coupled between the control end of the switching switch Q1 and the output side of the power converter 410, so that the switching switch Q1 is turned off when the output voltage of the output side exceeds the second threshold. For example, when the output side voltage of the power converter 410 exceeds the second threshold, the voltage will increase the control end potential of the voltage regulator device Q4 such as TL431 through the voltage divider formed by the resistor R3 and the resistor R4, thereby the cathode potential of the voltage regulator device Q4 is pulled down. Further, the potential at the gate of the P-type field effect transistor Q3 reaches the trigger voltage through the voltage division effect of the resistor R5 and the resistor R6, and the P-type field effect transistor Q3 is turned on. Further, the voltage division circuit formed by the resistor R7 and the resistor R8 triggers the N-type field effect transistor switch device Q2 to turn on after the P-type field effect transistor Q3 is turned on, thereby the potential of the control end of the switching switch Q1 is pulled down to the ground potential, so that the switching switch Q1 is turned off.

[0036] In some embodiments of the present disclosure, the power converter 410 includes a plurality of output ports located on the output side, and the load branch 421 is configured to be coupled to one of the plurality of output ports, the output voltage of which is higher than the output voltage of the other output ports. For example, the isolation transformer of the power converter 410 may arrange a plurality of secondary windings with different turns on the secondary side to provide output voltages of various voltage levels, such as 12V, 4.5V, 3.3V, etc. The load branch 421 may be coupled to the output port with the highest output voltage, such as an output port with a voltage of 12V. This is because, in order to help identify whether the power output of the photovoltaic power source 100 is sufficient to support the initialization of important components such as a processor, the auxiliary load RL in the load branch 421 generally needs to meet certain power level requirements, and for loads of the same power level, the auxiliary load RL with a higher voltage rating is easier to obtain and has a lower cost. In addition, when selecting an output port coupled to the load branch 421, the stability of the output voltage may also be considered, for example, the load branch 421 may be coupled to an output port having a main voltage feedback loop.

[0037] In the case where the load branch 421 is coupled to a 12V output port, for example, a processor such as a DSP in the control and drive component 300 can be powered by a 3.3V output port. The 3.3V output port is directly related to the voltage change of the 12V output port. In other words, as the output voltage of the 12V output port rises or falls, the output voltage of the 3.3V output port will also rise or fall. In some embodiments, the second threshold is lower than the voltage corresponding to the startup voltage of the processor in the control and drive component 300. For example, a processor such as a DSP will start to start only after the input voltage reaches 2.9V. In the case where the auxiliary startup circuit 420 is coupled to a 12V output port, the first threshold can be selected as 2V, and the second threshold can be selected as 5V. When the 12V output port reaches 5V, the 3.3V output port is usually just over 2V, which is lower than the startup voltage of a processor such as a DSP, 2.9V. In this way, after the output side voltage of the power converter 410 exceeds the second threshold value and the auxiliary load RL is cut off, a processor such as a DSP will start to start, which can avoid repeatedly starting the processor in the control and drive component 300 during the process of identifying a weak power source using the auxiliary load RL. However, it can be understood that the second threshold value can also be set higher, so that it is higher than the voltage corresponding to the start-up voltage of the processor, thereby starting the processor before cutting off the auxiliary load RL. In this case, even if the time of cutting off the auxiliary load RL is delayed, since the auxiliary load RL is connected after the output voltage exceeds the first threshold value, it is also helpful for the detection of the weak power source to avoid starting the processor when the power supply load capacity is insufficient.

[0038] In some embodiments of the present disclosure, the auxiliary startup circuit 420 is also coupled to the control and drive component 300, and is also configured to couple the auxiliary load RL to the output side based on a first voltage signal from the control and drive component 300, and to decouple the auxiliary load RL from the output side based on a second voltage signal from the control and drive component 300, the first voltage signal indicating that the processor in the control and drive component 300 has completed initialization, and the second voltage signal indicating that the output voltage of the photovoltaic power source 100 exceeds the third threshold after the control and drive component 300 sends the first voltage signal. As an example, as described above, during the first switching process of the auxiliary load RL in the load branch 421, if the power converter 410 does not lose power, it means that the output power of the photovoltaic power source 100 is sufficient to support the startup and initialization of the processor in the control and drive component 300. As the voltage of each output port of the power converter 410 increases and reaches the normal output voltage, the processor in the control and drive component 300 will be started and completed initialization. The control and drive component 300 can send a first voltage signal to indicate that the processor has completed initialization. The auxiliary start-up circuit 420 can connect the auxiliary load RL to the output side of the power converter 410 again based on the first voltage signal, so as to continue to determine whether the output power of the photovoltaic power source 100 is sufficient to support the subsequent control and drive of the power module 210 by the control and drive component 300 with the help of the auxiliary load RL. If the photovoltaic power source 100 cannot support the subsequent demand, the output voltage of the photovoltaic power source 100 will drop or the power converter 410 will lose power after the auxiliary load RL is connected for the second time, and if the photovoltaic power source 100 can support the subsequent demand, the output voltage of the photovoltaic power source 100 can be maintained above the third threshold, wherein the third threshold can be pre-set in the control and drive component 300 according to the specific situation of the photovoltaic power generation system 1000 (for example, the configuration of the photovoltaic power source 100). The control and drive component 300 can obtain the output voltage of the photovoltaic power source 100 through a device such as a voltage sensing device, and when it is determined that the output voltage of the photovoltaic power source 100 is above the third threshold, the control and drive component 300 can send a second voltage signal to the auxiliary start-up circuit 420 so that the auxiliary start-up circuit 420 cuts off the auxiliary load RL from the output side of the power conversion circuit 410. In one embodiment, when the auxiliary load RL is connected to the output side of the power converter 410 for the second time, if the output voltage of the photovoltaic power source 100 drops below the third threshold, the voltage control and drive component 300 may also wait for a certain period of time, such as 10 seconds. After waiting for a certain period of time, if the output voltage rises again to reach a fourth threshold greater than the third threshold, the control and drive component 300 may send a second voltage signal to cut off the auxiliary load RL.

[0039] After the auxiliary load RL is cut off, the control and drive component 300 may send a signal for turning on the electrical switch 220. As the electrical switch 220 is turned on, the power module 210 will perform power conversion under the control and drive of the control and drive module 300 to provide the output power of the photovoltaic power source 100 to the subsequent system, thereby completing the startup of the photovoltaic power generation system 1000. During the control of the electrical switch 220 to be turned on, an additional judgment step may be provided. Specifically, if the output voltage of the photovoltaic power source 100 drops below the third threshold after the electrical switch 220 is turned on, the voltage control and drive component 300 may wait for a certain time, such as 10 seconds. After waiting for a certain time, if the output voltage rises again to reach a fourth threshold greater than the third threshold, the control and drive component 300 may confirm that the startup of the photovoltaic power generation system 1000 is successful.

[0040] It can be seen that by switching on the auxiliary load RL for the second time, it is possible to pre-test whether the power of the photovoltaic power source 100 supports the control and drive component 300 to control and drive the power module 210, and whether the electrical switch 220 can be turned on, thereby avoiding the electrical switch 220 from being repeatedly closed when the power of the photovoltaic power source 100 is insufficient.

[0041] In some embodiments of the present disclosure, the auxiliary startup circuit 420 further includes a second branch 423, which is coupled to the control and drive component 300 and includes a plurality of resistors R9, R10 and at least one switch device Q5. The second branch 423 is configured to turn on the switching switch Q1 via the first branch 422 based on the first voltage signal from the control and drive component 300, and to turn off the switching switch Q1 via the first branch 422 based on the second voltage signal from the control and drive component 300. As an example, when the second branch 423 receives the first voltage signal from the control and drive component 300, the first voltage signal increases the base voltage of the bipolar transistor Q5 via the voltage division of the resistor R9 and the resistor R10 and triggers the bipolar transistor Q5 to turn on. Since the collector of the bipolar transistor Q5 is connected to the gate of the N-type field effect transistor Q2, the gate potential of the N-type field effect transistor Q2 is grounded, causing the N-type field effect transistor Q2 to be turned off. After the N-type field effect transistor Q2 is turned off, the potential of the control end of the switching switch Q1 is no longer grounded, but restored to the voltage divided by the resistor R1 and the resistor R2, which re-triggers the switching switch Q1 to turn on. When the second branch 423 receives the second voltage signal from the control and drive component 300, the bipolar transistor Q5 is turned off, and the N-type field effect transistor Q2 is turned on again, so that the control end of the switching switch Q1 is grounded, which causes the switching switch Q1 to be turned off. In this way, the auxiliary load RL can be simply and effectively switched for the second time based on the control signal from the control and drive component 300.

[0042] Figure 4 FIG. 4 shows a schematic circuit diagram of an auxiliary startup circuit 420 according to an alternative embodiment of the present disclosure. Figure 4 As shown, the auxiliary startup circuit 420 may include two load branches 421-1 and 421-1 connected in parallel with each other. In this way, the auxiliary load RL can adopt a higher power level, and because the parallel load branches are adopted, the current pressure of the switching device such as the bipolar transistor can be reduced. In some embodiments, instead of the P-type field effect transistor, the switching device Q3 in the second bias part 4222 of the first branch 422 can use an optocoupler switch. The optocoupler switch has the advantages of strong anti-interference ability, long life, and high reliability. It can be understood that the switching devices Q1, Q2, Q3, Q4 and Q5 mentioned above are not limited to the switch types shown in the figure, but can be other appropriate types of switching devices, including but not limited to insulated gate bipolar transistor (IGBT), junction gate field effect transistor (JFET), bipolar junction transistor (BJT), metal oxide semiconductor field effect transistor (MOSFET), gate turn off thyristor (GTO), MOS controlled thyristor (MCT), integrated gate commutated thyristor (IGCT), silicon carbide (SiC) switching device or gallium nitride (GaN) switching device, etc. Figure 4 Other configurations in are similar to Figure 3 , so I will not go into details.

[0043] Through the teachings given in the above description and the related drawings, many modifications and other embodiments of the present disclosure given here will be recognized by those skilled in the art of the present disclosure. Therefore, it is to be understood that the embodiments of the present disclosure are not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included in the scope of the present disclosure. In addition, although the above description and the related drawings describe the example embodiments in the context of some example combinations of parts and / or functions, it should be appreciated that different combinations of parts and / or functions can be provided by alternative embodiments without departing from the scope of the present disclosure. In this regard, for example, other combinations of parts and / or functions that are different from those clearly described above are also expected to be within the scope of the present disclosure. Although specific terms are used here, they are only used in a general and descriptive sense and are not intended to be limited.

Claims

1. A power supply device (400), comprising: A power converter (410) configured to be coupled to a power source at an input side of the power converter and to be coupled to a power supply target at an output side of the power converter, the power supply target comprising a control and drive component (300); and An auxiliary startup circuit (420) comprises an auxiliary load (RL), the auxiliary startup circuit (420) being coupled to the output side of the power converter (410) and being configured to couple the auxiliary load (RL) to the output side of the power converter when the voltage of the output side of the power converter reaches a first threshold so that the auxiliary load (RL) receives the output power from the power converter at the output side of the power converter, and to decouple the auxiliary load (RL) from the output side of the power converter when the voltage of the output side of the power converter reaches a second threshold higher than the first threshold.

2. The power supply device (400) according to claim 1, wherein the power source comprises a photovoltaic power source (100) of a photovoltaic power generation system (1000), and the power supply target comprises a control and drive component (300) of the photovoltaic power generation system (1000).

3. The power supply device (400) according to claim 2, wherein the auxiliary startup circuit (420) is also coupled to the control and drive component (300), and is also configured to couple the auxiliary load (RL) to the output side of the power converter based on a first voltage signal from the control and drive component (300), and to decouple the auxiliary load (RL) from the output side of the power converter based on a second voltage signal from the control and drive component (300), wherein the first voltage signal indicates that the processor in the control and drive component (300) has completed initialization, and the second voltage signal indicates that the output voltage of the photovoltaic power source (100) exceeds a third threshold after the control and drive component (300) issues the first voltage signal.

4. The power supply device (400) according to claim 3, wherein the auxiliary starting circuit (420) comprises: At least one load branch (421), each load branch (421) comprising an auxiliary load (RL) and a switching switch (Q1) connected in series, and coupled to the output side of the power converter (410); and A first branch (422) is coupled to a control end of the switching switch (Q1) and the output side of the power converter (410), wherein the first branch (422) is configured to turn on the switching switch (Q1) based on an output voltage on the output side of the power converter exceeding a first threshold, and to turn off the switching switch (Q1) based on an output voltage on the output side of the power converter exceeding a second threshold.

5. The power supply device (400) according to claim 4, wherein the auxiliary starting circuit (420) further comprises: The second branch (423) is coupled to the control and drive component (300) and comprises a plurality of resistor elements (R9, R10) and at least one switch device (Q5), wherein the second branch (423) is configured to switch on the switching switch (Q1) via the first branch (422) based on the first voltage signal from the control and drive component (300), and to switch off the switching switch (Q1) via the first branch (422) based on the second voltage signal from the control and drive component (300).

6. The power supply device (400) according to claim 4, wherein the first branch (422) comprises: A first biasing unit (4221) comprising at least one resistor element (R1, R2) coupled between a control end of the switching switch (Q1) and an output side of the power converter (410), so that the switching switch (Q1) is turned on when the output voltage of the output side of the power converter exceeds the first threshold value; as well as The second biasing unit (4222) comprises a plurality of resistor elements (R3, R4, R5, R6, R7, R8) and at least one switching device (Q2, Q3, Q4) coupled between the control end of the switching switch (Q1) and the output side of the power converter (410), so that the switching switch (Q1) is turned off when the output voltage of the output side of the power converter exceeds a second threshold value.

7. The power supply device (400) according to claim 4, wherein the power converter (410) comprises a plurality of output ports located at the output side of the power converter, and the load branch (421) is configured to be coupled to one of the plurality of output ports, the output voltage of the one output port being higher than the output voltages of the other output ports.

8. The power supply device (400) according to claim 2 or 3, wherein the second threshold value is lower than a voltage corresponding to a startup voltage of a processor in the control and drive component (300).

9. The power supply device (400) according to claim 4, wherein the at least one load branch (421) comprises two load branches connected in parallel with each other.

10. A photovoltaic power generation system (1000), comprising: Photovoltaic power source (100) and main power circuit (200); A control and drive component (300) configured to control the main power circuit (200); and The power supply device (400) according to any one of claims 1 to 9, is configured to receive power from the photovoltaic power source (100) and output power to the control and drive component (300).

11. The photovoltaic power generation system (1000) according to claim 10, wherein the main power circuit (200) comprises a power module (210) and an electrical switch (220) coupled in series between the photovoltaic power source (100) and the system load (2000), and the control and drive component (300) is configured to send a signal for turning on the electrical switch (220) after sending a voltage signal to couple the auxiliary load (RL) of the auxiliary startup circuit (420) to the output side of the power converter (410) and to decouple the auxiliary load (RL) from the output side of the power converter.

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