CN117240057B - Power converter, control method thereof and photovoltaic power generation system - Google Patents
Power converter, control method thereof and photovoltaic power generation system Download PDFInfo
- Publication number
- CN117240057B CN117240057B CN202311499546.1A CN202311499546A CN117240057B CN 117240057 B CN117240057 B CN 117240057B CN 202311499546 A CN202311499546 A CN 202311499546A CN 117240057 B CN117240057 B CN 117240057B
- Authority
- CN
- China
- Prior art keywords
- power
- conversion circuit
- power conversion
- switching tube
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000010248 power generation Methods 0.000 title claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 174
- 230000009471 action Effects 0.000 claims abstract description 22
- 230000009977 dual effect Effects 0.000 claims description 4
- 230000005611 electricity Effects 0.000 claims description 2
- 239000003990 capacitor Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 101100112673 Rattus norvegicus Ccnd2 gene Proteins 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Landscapes
- Dc-Dc Converters (AREA)
- Inverter Devices (AREA)
Abstract
The application relates to the field of photovoltaic power generation, in particular to a power converter, a control method thereof and a photovoltaic power generation system, wherein the power converter comprises: at least one power conversion circuit comprising at least one switching tube for performing power conversion; the control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit; and the auxiliary power supply circuit is connected with the control circuit and the input end of the at least one power conversion circuit and is used for taking power from the input end of the power conversion circuit and supplying power to the control circuit. Before the control circuit controls the power conversion circuit to output power, the control circuit controls at least one switching tube of at least one power conversion circuit to perform switching action at preset frequency, and judges whether to control the power conversion circuit to output power according to the drop value of the input voltage of the power conversion circuit, the input end of which is connected with the auxiliary power supply circuit. The method is more accurate and efficient in weak light judgment, and meanwhile, the problem of repeated restarting of the photovoltaic equipment is avoided.
Description
Technical Field
The present disclosure relates to the field of photovoltaic power generation, and in particular, to a power converter, a control method thereof, and a photovoltaic power generation system.
Background
Due to the reproducibility and cleanliness of solar energy, photovoltaic power generation technology has been rapidly developed. The string photovoltaic system has wide application in the photovoltaic power generation field due to the advantages of mature technology, high conversion efficiency, low price and the like. In order to realize the control of the module level, the photovoltaic module is generally connected into a string through the photovoltaic power generation equipment, such as an optimizer, a shutoff device, a micro inverter and the like, and weak light judgment can be carried out during power-on starting so as to prevent the output power of the photovoltaic module from being too low (such as in the morning) to cause shaking or the repeated restarting of the photovoltaic power generation equipment.
At present, the weak light judging mode of the photovoltaic power generation equipment is basically judged by the magnitude of the input voltage of the photovoltaic power generation equipment when the photovoltaic power generation equipment is electrified, if the input voltage is smaller than a threshold value, the weak light is considered to be required to wait for a certain time, and the magnitude of the input voltage cannot fully reflect the magnitude of the output power of the photovoltaic module. The method has the defects of inaccurate judgment, difficult determination of the threshold value and the like.
Disclosure of Invention
In view of the above, it is desirable to provide a power converter, a control method thereof, and a photovoltaic power generation system.
In a first aspect, an embodiment of the present invention proposes a power converter, the power converter comprising:
at least one power conversion circuit comprising at least one switching tube for performing power conversion;
the control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit;
the auxiliary power supply circuit is connected with the control circuit and the input end of at least one power conversion circuit, and is used for taking electricity from the input end of the power conversion circuit and supplying power to the control circuit;
before the control circuit controls the power conversion circuit to output power, the control circuit controls at least one switching tube of at least one power conversion circuit to perform switching action at preset frequency, and judges whether to control the power conversion circuit to output power according to the drop value of the input voltage of the power conversion circuit, the input end of which is connected with the auxiliary power supply circuit.
In an embodiment, the control circuit controls the power conversion circuit to start power output in case that a drop value of an input voltage of the power conversion circuit is smaller than a threshold value.
In an embodiment, the control circuit controls the corresponding switching tube to stop switching action when the drop value of the input voltage of the power conversion circuit is greater than or equal to a threshold value, and controls the corresponding switching tube to perform switching action at a preset frequency again after a preset time interval.
In one embodiment, the control circuit includes:
a control module for generating a control signal for controlling the power conversion circuit;
the driving module is connected with the power conversion circuit and the control module and generates a driving signal according to the control signal so as to drive at least one switching tube,
before the power conversion circuit outputs power, the driving module generates a driving signal according to a control signal provided by the control module to drive a corresponding switching tube to perform switching action at preset frequency, and the control module judges whether to control the power conversion circuit to perform power output according to the drop value of the input voltage.
In one embodiment, the power conversion circuit comprises a first switch tube, a second switch tube and a first inductor;
the first end of the first switching tube is connected with the input end of the power conversion circuit, the second end of the first switching tube is connected with the first end of the inductor, the second end of the inductor is connected with the output end of the power conversion circuit, and the first end of the second switching tube is connected with the second end of the first switching tube;
before the power conversion circuit outputs power, the control circuit controls the second switching tube to conduct switching action at preset frequency.
In one embodiment, the power conversion circuit comprises a third switching tube, a fourth switching tube and a second inductor;
the first end of the second inductor is connected with the input end of the power conversion circuit, the second end of the second inductor is connected with the first end of the third switching tube, the second end of the third switching tube is connected with the output end of the power conversion circuit, and the first end of the fourth switching tube is connected with the second end of the second inductor;
before the power conversion circuit outputs power, the control circuit controls the third switching tube to conduct switching action at preset frequency.
In one embodiment, the power conversion circuit comprises a fifth switching tube and a sixth switching tube;
the first end of the fifth switching tube is connected with the input end of the power conversion circuit, the second end of the fifth switching tube is connected with the output end of the power conversion circuit, and the first end of the sixth switching tube is connected with the second end of the fifth switching tube;
before the power conversion circuit outputs power, the control circuit controls the sixth switching tube to conduct switching action at preset frequency.
In one embodiment, the predetermined frequency is in the range of 1KHz to 10MHz.
In an embodiment, the power conversion circuit comprises one of a buck circuit, a boost circuit, a buck-boost circuit, a full-bridge circuit, a half-bridge circuit, a multi-level inverter circuit, and a dual active bridge type converter circuit.
In a second aspect, an embodiment of the present invention proposes a control method for a power converter, for a power converter according to the first aspect, the method comprising:
before controlling the output power of the power conversion circuit, controlling at least one switching tube of at least one power conversion circuit to perform switching action at a preset frequency;
and judging whether to control the power conversion circuit to output power according to the drop value of the input voltage of the power conversion circuit with the input end connected with the auxiliary power supply circuit.
In an embodiment, the power conversion circuit is controlled to start power output when a drop value of an input voltage of the power conversion circuit is smaller than a threshold value.
In an embodiment, when the drop value of the input voltage of the power conversion circuit is greater than or equal to a threshold value, the corresponding switching tube is controlled to stop the switching operation, and after a preset time interval, the corresponding switching tube is controlled to perform the switching operation at a preset frequency again.
In one embodiment, the predetermined frequency is in the range of 1KHz to 10MHz.
In a third aspect, an embodiment of the present invention provides a photovoltaic power generation system, including at least one photovoltaic dc power source and the power converter according to the first aspect correspondingly connected to the photovoltaic dc power source.
According to the power conversion circuit control method, before the power conversion circuit outputs power, at least one switching tube of at least one power conversion circuit is controlled to conduct switching action at preset frequency, whether the power conversion circuit is controlled to conduct power output is judged according to the falling value of the input voltage of the power conversion circuit, the problem that the input power of a power converter is too low, the starting power output possibly causes unstable operation of later-stage equipment, the influence on the auxiliary power circuit is also possibly caused, even the problem that photovoltaic equipment is restarted repeatedly is solved, and the power conversion circuit control method is simple, judgment is more accurate, and efficiency is higher.
Drawings
FIG. 1 is a schematic diagram of a power converter according to an embodiment of the disclosure;
FIG. 2 is a schematic diagram of a control circuit according to an embodiment of the disclosure;
fig. 3 is a schematic structural diagram of a power converter in a first exemplary embodiment provided herein;
FIG. 4 is a waveform diagram of an input voltage of a power conversion circuit in a first exemplary embodiment provided herein;
fig. 5 is a schematic structural diagram of a power converter in a second exemplary embodiment provided herein;
fig. 6 is a schematic diagram of a power conversion circuit in a third exemplary embodiment provided herein;
fig. 7 is a schematic diagram of a power conversion circuit in a fourth exemplary embodiment provided herein;
FIG. 8 is a flow chart of a control method of a power converter according to an embodiment of the disclosure;
fig. 9 is a schematic structural diagram of a photovoltaic power generation system according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described and illustrated below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden on the person of ordinary skill in the art based on the embodiments provided herein, are intended to be within the scope of the present application. Moreover, it should be appreciated that while such a development effort might be complex and lengthy, it would nevertheless be a routine undertaking of design, fabrication, or manufacture for those of ordinary skill having the benefit of this disclosure, and thus should not be construed as having the benefit of this disclosure.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is to be expressly and implicitly understood by those of ordinary skill in the art that the embodiments described herein can be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. Reference to "a," "an," "the," and similar terms herein do not denote a limitation of quantity, but rather denote the singular or plural. The terms "comprising," "including," "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to only those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "connected," "coupled," and the like in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" as used herein means greater than or equal to two. "and/or" describes an association relationship of an association object, meaning that there may be three relationships, e.g., "a and/or B" may mean: a exists alone, A and B exist together, and B exists alone. The terms "first," "second," "third," and the like, as used herein, are merely distinguishing between similar objects and not representing a particular ordering of objects.
As shown in fig. 1, an embodiment of the present invention proposes a power converter 10, including: at least one power conversion circuit 100, the power conversion circuit 100 comprising at least one switching tube for performing power conversion; a control circuit 200 connected to the power conversion circuit 100 for controlling the power conversion circuit 100; the auxiliary power supply circuit 300 is connected to the control circuit 200 and the input terminal of at least one power conversion circuit 100, and is used for taking power from the input terminal of the power conversion circuit 100 and supplying power to the control circuit 200.
Before controlling the power conversion circuit 100 to output power, the control circuit 200 controls at least one switching tube to perform switching operation at a preset frequency, and determines whether to control the power conversion circuit 100 to output power according to a drop value of an input voltage Vin of the power conversion circuit 100, where an input end of the drop value is connected to the auxiliary power supply circuit 300.
In practical applications, the power converter 10 is a photovoltaic device such as a photovoltaic optimizer, a chopper, a photovoltaic inverter, etc. The input end of the power converter 10 may be connected to a photovoltaic dc power supply, to obtain the output power of the photovoltaic dc power supply, and provide the output voltage Vout through power conversion. While the auxiliary power supply circuit 300 draws power from the corresponding photovoltaic dc power source to supply power to the control circuit 200. The photovoltaic direct current power source may be a single photovoltaic module, a single sub-string of photovoltaic cells, a plurality of photovoltaic modules connected in series and/or parallel, a plurality of sub-strings of photovoltaic cells connected in series and/or parallel.
When the photovoltaic direct-current power supply for supplying power to the auxiliary power supply circuit 300 is in a weak light state, the output power of the photovoltaic direct-current power supply is low, at this time, the control circuit 200 controls the switching tube corresponding to the power conversion circuit to perform high-frequency switching action, and the input voltage fluctuation of the corresponding input end of the power converter is larger; when the photovoltaic direct current power supply is in a non-weak light state, the output power of the photovoltaic direct current power supply is high, the switching tube is controlled to be used for high-frequency switching, the fluctuation of the input voltage of the power converter corresponding to the input end is smaller, and the larger the output power provided by the photovoltaic direct current power supply is, the smaller the fluctuation of the input voltage of the power converter is, so that before the power converter is started to output power, whether the photovoltaic direct current power supply is in a weak light state can be judged according to the falling value of the input voltage of the corresponding input end when the switching tube of the power conversion circuit is used for high-frequency switching, and whether the power converter can be started to output power can be judged according to the falling value.
When the drop value of the input voltage of the power conversion circuit 100 is smaller than the threshold value, the control circuit 200 controls the power conversion circuit 100 to start power output; when the drop value of the input voltage of the power conversion circuit 100 is greater than or equal to the threshold value, the control circuit 200 controls the corresponding switching tube to stop the switching operation, and after a preset time interval, the control circuit 200 controls the corresponding switching tube again to perform the switching operation at a preset frequency, and performs judgment.
The threshold may be determined according to power, for example, when the output power of the photovoltaic module is less than 5W, the photovoltaic module is considered to be in a weak light state, otherwise, the photovoltaic module is considered to be in a non-weak light state, and the threshold may be determined according to a fluctuation value of the input voltage when the output power of the photovoltaic module is 5W.
The preset frequency can be in a range from a few KHz to a few MHZ, for example, 1KHZ-10MHZ, but the higher the frequency is, the larger the drop value of the input voltage Vin is, and the more accurate the detection is. Therefore, the appropriate threshold value can be set according to the actual working condition.
In this embodiment, before the control circuit 200 controls the power conversion circuit 100 to output power, at least one switching tube of at least one power conversion circuit 100 is controlled to perform switching operation at a preset frequency, and according to a drop value of an input voltage of the power conversion circuit 100, which is connected with the auxiliary power supply circuit 300 at an input end, whether the power conversion circuit is controlled to perform power output is judged, so that the problem that the operation of a rear-stage device is unstable, the influence on the auxiliary power supply circuit is also caused, and even the repeated restarting of a photovoltaic device is caused due to the fact that the input power of the power converter is too low and the starting power output is possibly caused is solved.
In one embodiment, as shown in fig. 2, the control circuit 200 includes: a control module 220 for generating a control signal for controlling the power conversion circuit; the driving module 210 is connected to the power conversion circuit 100 and the control module 220, and generates a driving signal according to the control signal to drive at least one switching tube.
Before the power conversion circuit 100 outputs power, the driving module 210 generates at least one driving signal according to the control signal provided by the control module 220 to drive the corresponding switching tube to perform a switching operation at a preset frequency. The control module 220 determines whether to control the output power of the power conversion circuit 100, i.e. whether to start the power converter to output power, according to the drop value of the input voltage Vin.
In the case that the drop value of the input voltage Vin of the power conversion circuit 100 is smaller than the threshold value, the control module 220 controls the power conversion circuit 100 to start power output; when the drop value of the input voltage Vin of the power conversion circuit 100 is greater than or equal to the threshold value, the control circuit 200 controls the corresponding switching tube to stop the switching operation, and after a preset time interval, the control circuit 200 controls the corresponding switching tube to perform the switching operation again at a preset frequency, and performs judgment.
Further, the control circuit 200 further includes a sampling module for obtaining a drop value of the input voltage Vin, for example, by sampling the input voltage Vin.
In an exemplary embodiment, the power converter is an optimizer, and is connected to the output end of the photovoltaic dc power source PV, so as to achieve the maximum power output of the photovoltaic dc power source, and the power conversion circuit 100 may use a buck circuit. As shown in fig. 3, the power conversion circuit 100 includes a first switching tube S1, a second switching tube S2, a first inductor L1, an input capacitor Cin1, and an output capacitor Cout1. The first end of the first switching tube S1 is connected with the input end of the power conversion circuit 100, the second end of the first switching tube S1 is connected with the first end of the inductor L1, the second end of the inductor L1 is connected with the output end of the power conversion circuit 100, and the first end of the second switching tube S2 is connected with the second end of the first switching tube S1. The input capacitor Cin1 is connected in parallel to the input terminal of the power conversion circuit 100, and the output capacitor Cout1 is connected in parallel to the output terminal of the power conversion circuit 100.
The first switching tube S1 is connected between the input end and the output end of the power conversion circuit 100, and is used for controlling the output power of the power conversion circuit 100; the second switching tube S2 provides a freewheel path as a freewheel tube.
After the power converter is powered on or ready to start power output or receive a safe operation heartbeat or receive a start signal, the control circuit 200 controls the first switching tube S1 to be disconnected, the second switching tube S2 to perform high-frequency switching operation at a preset frequency, and as the auxiliary power supply circuit 300 is connected with the photovoltaic direct-current power supply PV from the input end thereof to supply power to the control circuit 200, the driving module 210 drives the second switching tube S2 to perform high-frequency switching operation to consume the energy of the photovoltaic direct-current power supply PV, so that the input voltage Vin of the power converter drops.
When the drop value of the input voltage Vin is greater than the threshold value, the photovoltaic direct-current power supply PV is considered to be in a weak light state, the electric energy provided by the photovoltaic direct-current power supply PV is insufficient for starting the power output of the power converter, the second switching tube S2 is controlled to stop the switching action, and the switching state is switched to the off state; conversely, when the drop value of the input voltage Vin is smaller than the threshold value, the first switching tube S1 and the second switching tube S2 are controlled to start to work normally, and the power output of the power conversion circuit 100 is started, for example, the power conversion circuit 100 is controlled to work in a pass-through mode (for example, the first switching tube S1 is controlled to be normally on, the second switching tube S2 is controlled to be off) or a chopping mode, so as to provide power to the subsequent devices.
When the photovoltaic direct current power supply PV is in a low light state, the first switching tube S1 is controlled to be turned off again after waiting for a short time, the second switching tube S2 is controlled to perform high-frequency switching operation at a preset frequency, and whether to start the power output of the power conversion circuit 100 is determined according to the drop value of the input voltage Vin.
In this example embodiment, assuming that the photovoltaic dc power supply PV is in a low light state when its output power is less than 3.5W, the second switching tube S2 is set to perform a high frequency switching operation at a preset frequency of 1MHZ with a duty ratio of 50%, and the threshold is set to 2V. Through practical experiments, when the input power of the power converter is smaller than 3.5W, the drop value of the input voltage Vin of the input end is larger than 2V, so that the scheme is proved to be accurate in judgment and high in reliability.
The following will be described in connection with the operational waveform diagram shown in fig. 4:
as shown in fig. 4: at time T0, the power converter is powered up, and before that, each switching tube in the power converter is not operated, and both the first switching tube S1 and the second switching tube S2 are turned off, and at this time, the value of the input voltage Vin at the input terminal is U0.
At time T0, the control circuit 200 controls the second switching transistor S2 of the power conversion circuit 100 to start the high frequency switching operation, the first switching transistor S1 is turned off, the input voltage Vin gradually decreases due to the consumption of energy by the driving module 210, and at time T1, the input voltage Vin decreases to the voltage U1 and continues to be maintained.
Since the difference between the voltage U0 and the voltage U1 is determined to be greater than the set threshold, the photovoltaic dc power supply is considered to be in a weak light state, and at time T2, the second switching tube S2 is controlled to stop the high-frequency switching operation, switch to the off state, the first switching tube S1 remains off, and the input voltage Vin starts to rise.
As the illumination intensity increases, at time T4, the input voltage Vin rises to the voltage U2. At time T5, the second switching tube S2 is controlled again to start to perform a high-frequency switching operation, the first switching tube S1 is still kept off, the input voltage Vin drops to the voltage U3 due to the consumption of energy by the driving module 210, and continues to be maintained, and the photovoltaic direct-current power supply is considered to be in a non-weak light state due to the difference between the voltage U2 and the voltage U3 being smaller than the threshold value, so that the power conversion circuit 100 is controlled to start to work normally, and power output is started.
In a second exemplary embodiment, as shown in fig. 5, a multi-input power converter is provided, which includes two power conversion circuits 100, the input ends of the two power converters are respectively connected to one photovoltaic dc power source PV, and the output ends of the two power conversion circuits 100 may be connected in series or in parallel, and this exemplary embodiment is illustrated by taking a series connection as an example.
Specifically, the auxiliary power supply circuit 300 is connected to an input terminal of one of the power conversion circuits 100, and supplies power to the control circuit 200 by taking power from a photovoltaic dc power supply connected to the power conversion circuit 100.
Specifically, after the power converter is powered on or when the power converter is ready to start power output or when a safe operation heartbeat is received or a start signal is received, the control circuit 200 controls a corresponding switching tube in at least one power conversion circuit 100 to perform high-frequency switching action at a preset frequency, and judges whether to start power output of the power converter according to a drop value of the input voltage Vin 1.
For example, the control circuit 200 controls the corresponding switching tube in one power conversion circuit 100 to perform the high-frequency switching operation at the preset frequency (refer to the first exemplary embodiment specifically), the other power conversion circuit 100 does not operate, and the control circuit 200 determines whether to start the power output of the power converter according to the droop value of the input voltage Vin 1.
When the drop value of the input voltage Vin1 is greater than the threshold value, the photovoltaic direct current power supply PV1 is considered to be in a weak light state, the electric energy provided by the photovoltaic direct current power supply PV1 is insufficient for the power converter to start power output, and each power conversion circuit 100 does not output power; when the drop value of the input voltage Vin1 is smaller than the threshold value, the photovoltaic dc power supply PV1 is considered to be in a non-weak light state, and each power conversion circuit 100 is controlled to start to work normally, so as to output power, for example, each power conversion circuit 100 is controlled to work in a pass-through mode or a chopper mode, and power is supplied to the subsequent devices.
Alternatively, the auxiliary power supply circuit 300 may be connected to the input terminals of the two power conversion circuits 100, and may supply power from the photovoltaic dc power source PV connected to any one of the power conversion circuits 100 to the control circuit 200.
In the third exemplary embodiment, the power conversion circuit 100 may employ a boost circuit, and as shown in fig. 6, the power conversion circuit 100 includes a third switching tube S3, a fourth switching tube S4, a second inductor L2, an input capacitor Cin2, and an output capacitor Cout2. The first end of the second inductor L2 is connected with the input end of the power conversion circuit 100, the second end of the second inductor L2 is connected with the first end of the third switching tube S3, the second end of the third switching tube S3 is connected with the output end of the power conversion circuit 100, and the first end of the fourth switching tube S4 is connected with the second end of the second inductor L2; the input capacitor Cin2 is connected in parallel to the input terminal of the power conversion circuit 100, and the output capacitor Cout2 is connected in parallel to the output terminal of the power conversion circuit 100.
The third switching tube S3 is connected between the input and output terminals of the power conversion circuit 100 as a follow current tube for providing a follow current channel.
The third switching transistor S4 is used to control the output power of the power conversion circuit 100.
Specifically, the control circuit 200 may control the fourth switching tube S4 to be turned off, and control the third switching tube S3 to perform the high-frequency switching operation at the preset frequency, and other points similar to those of the first exemplary embodiment are not described herein.
In a fourth exemplary embodiment, the power converter is a chopper, either a single-input chopper or a multiple-input chopper. As shown in fig. 7, the power conversion circuit 100 includes a fifth switching transistor S5, a sixth switching transistor S6, and an input capacitor Cin3. The first end of the fifth switching tube S5 is connected with the input end of the power conversion circuit 100, the second end of the fifth switching tube S5 is connected with the output end of the power conversion circuit 100, and the first end of the sixth switching tube S6 is connected with the second end of the fifth switching tube S5; the input capacitor Cin3 is connected in parallel to the input terminal of the power conversion circuit 100.
The fifth switching tube S5 is connected between the input end and the output end of the power conversion circuit 100, and is used for controlling output power; the sixth switching tube S6 provides a freewheel path as a follow-on tube.
Similarly to the first exemplary embodiment, by controlling the fifth switching tube S5 to be turned off and controlling the sixth switching tube S6 to perform the high-frequency switching operation at the preset frequency, it is determined whether to start the power output according to the drop value of the input voltage Vin.
In other embodiments, the power conversion circuit may employ a buck-boost circuit or a dual active bridge DC-DC conversion circuit.
In other embodiments, the power conversion circuit may be a DC-AC circuit, including, for example, a full bridge circuit or a half bridge circuit or a multi-level inverter circuit or a dual active bridge inverter circuit.
For example, when the full-bridge circuit is included, for example, the lower switching tube of two bridge arms or any bridge arm is controlled to perform high-frequency switching action at a preset frequency, other switching tubes are disconnected, and other points similar to those of the first exemplary embodiment are not described again.
Based on the above embodiments, the embodiment of the present invention further provides a method for controlling a power converter, as shown in fig. 8, where the method includes:
s802: before controlling the output power of the power conversion circuit, controlling at least one switching tube of at least one power conversion circuit to perform switching action at a preset frequency;
s804: and judging whether to control the power conversion circuit to output power according to the drop value of the input voltage of the power conversion circuit with the input end connected with the auxiliary power supply circuit.
In this embodiment, before the power conversion circuit outputs power, at least one switching tube of at least one power conversion circuit is controlled to perform switching action at a preset frequency, and whether the power conversion circuit is controlled to perform power output is judged according to a drop value of an input voltage of the power conversion circuit, which is connected with the auxiliary power supply circuit, so that the problem that the operation of a rear-stage device is unstable, the auxiliary power supply circuit is influenced, and even the photovoltaic device is restarted repeatedly due to the fact that the input power of the power converter is too low and the starting power output is likely to cause the unstable operation of the rear-stage device is solved.
In an embodiment, the power conversion circuit is controlled to start power output when a drop value of an input voltage of the power conversion circuit is smaller than a threshold value.
In an embodiment, when the drop value of the input voltage of the power conversion circuit is greater than or equal to a threshold value, the corresponding switching tube is controlled to stop the switching operation, and after a preset time interval, the corresponding switching tube is controlled to perform the switching operation at a preset frequency again.
In one embodiment, the predetermined frequency is in the range of 1KHz to 10MHz.
It should be noted that, the specific limitation of the control method of the power converter may be referred to the limitation of the power converter hereinabove, and will not be described herein.
The embodiment of the present invention also proposes a photovoltaic power generation system, as shown in fig. 9, including at least one photovoltaic dc power source PV and at least one power converter 10 described in the foregoing embodiment correspondingly connected to the photovoltaic dc power source PV. The outputs of the power converters 10 are connected in series and/or parallel to the junction device 20, and the junction device 20 may be an inverter or a junction box.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples represent only a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (12)
1. A power converter, the power converter comprising:
at least one power conversion circuit comprising at least one switching tube for performing power conversion;
the control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit;
the auxiliary power supply circuit is connected with the control circuit and the input end of at least one power conversion circuit, and is used for taking electricity from the input end of the power conversion circuit and supplying power to the control circuit;
before the control circuit controls the power conversion circuit to output power, the control circuit controls at least one switching tube of at least one power conversion circuit to conduct switching action at preset frequency, judges whether the power conversion circuit is controlled to conduct power output according to the falling value of the input voltage of the power conversion circuit, and controls the power conversion circuit to conduct power output under the condition that the falling value of the input voltage of the power conversion circuit is smaller than a threshold value.
2. The power converter according to claim 1, wherein the control circuit controls the corresponding switching tube to stop switching operation in the case that the drop value of the input voltage of the power conversion circuit is equal to or greater than a threshold value, and the control circuit controls the corresponding switching tube to perform switching operation again at a preset frequency after a preset time interval.
3. The power converter of claim 1, wherein the control circuit comprises:
a control module for generating a control signal for controlling the power conversion circuit;
the driving module is connected with the power conversion circuit and the control module and generates a driving signal according to the control signal so as to drive at least one switching tube,
before the power conversion circuit outputs power, the driving module generates a driving signal according to a control signal provided by the control module to drive a corresponding switching tube to perform switching action at a preset frequency, and the control module judges whether to control the power conversion circuit to perform power output according to the drop value of the input voltage.
4. The power converter of claim 1, wherein the power conversion circuit comprises a first switching tube, a second switching tube, a first inductor;
the first end of the first switching tube is connected with the input end of the power conversion circuit, the second end of the first switching tube is connected with the first end of the inductor, the second end of the inductor is connected with the output end of the power conversion circuit, and the first end of the second switching tube is connected with the second end of the first switching tube;
before the power conversion circuit outputs power, the control circuit controls the second switching tube to conduct switching action at preset frequency.
5. The power converter of claim 1, wherein the power conversion circuit comprises a third switching tube, a fourth switching tube, and a second inductor;
the first end of the second inductor is connected with the input end of the power conversion circuit, the second end of the second inductor is connected with the first end of the third switching tube, the second end of the third switching tube is connected with the output end of the power conversion circuit, and the first end of the fourth switching tube is connected with the second end of the second inductor;
before the power conversion circuit outputs power, the control circuit controls the third switching tube to conduct switching action at preset frequency.
6. The power converter of claim 1, wherein the power conversion circuit comprises a fifth switching tube, a sixth switching tube;
the first end of the fifth switching tube is connected with the input end of the power conversion circuit, the second end of the fifth switching tube is connected with the output end of the power conversion circuit, and the first end of the sixth switching tube is connected with the second end of the fifth switching tube;
before the power conversion circuit outputs power, the control circuit controls the sixth switching tube to conduct switching action at preset frequency.
7. The power converter of claim 1, wherein the predetermined frequency is in the range of 1KHZ-10MHZ.
8. The power converter of claim 1, wherein the power conversion circuit comprises one of a buck circuit, a boost circuit, a buck-boost circuit, a full-bridge circuit, a half-bridge circuit, a multi-level inverter circuit, a dual active bridge type conversion circuit.
9. A control method of a power converter for a power converter according to any one of claims 1 to 8, the method comprising:
before controlling the output power of the power conversion circuit, controlling at least one switching tube of at least one power conversion circuit to perform switching action at a preset frequency;
judging whether to control the power conversion circuit to output power according to the drop value of the input voltage of the power conversion circuit with the input end connected with the auxiliary power supply circuit;
and controlling the power conversion circuit to start power output under the condition that the drop value of the input voltage of the power conversion circuit is smaller than a threshold value.
10. The method according to claim 9, wherein when the drop value of the input voltage of the power conversion circuit is equal to or greater than a threshold value, the corresponding switching tube is controlled to stop the switching operation, and after a predetermined time interval, the corresponding switching tube is controlled to perform the switching operation again at a predetermined frequency.
11. The method of claim 9, wherein the predetermined frequency is in the range of 1KHZ to 10MHZ.
12. A photovoltaic power generation system comprising at least one photovoltaic dc power source and the power converter of any one of claims 1 to 8 correspondingly connected to the photovoltaic dc power source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311499546.1A CN117240057B (en) | 2023-11-09 | 2023-11-09 | Power converter, control method thereof and photovoltaic power generation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311499546.1A CN117240057B (en) | 2023-11-09 | 2023-11-09 | Power converter, control method thereof and photovoltaic power generation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117240057A CN117240057A (en) | 2023-12-15 |
| CN117240057B true CN117240057B (en) | 2024-03-26 |
Family
ID=89089741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311499546.1A Active CN117240057B (en) | 2023-11-09 | 2023-11-09 | Power converter, control method thereof and photovoltaic power generation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117240057B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017148241A1 (en) * | 2016-02-29 | 2017-09-08 | 中兴通讯股份有限公司 | Inverter control method, device, and power generation system |
| CN216530687U (en) * | 2021-11-26 | 2022-05-13 | 深圳市正浩创新科技股份有限公司 | Photovoltaic power supply control circuit, photovoltaic power supply control device and power supply equipment |
| CN114614663A (en) * | 2020-12-03 | 2022-06-10 | 台达电子企业管理（上海）有限公司 | Control method, auxiliary power supply of photovoltaic inverter and photovoltaic power generation system |
| CN116131575A (en) * | 2023-01-13 | 2023-05-16 | 华为数字能源技术有限公司 | Power conversion apparatus and control method thereof |
| CN116800096A (en) * | 2023-08-24 | 2023-09-22 | 杭州禾迈电力电子股份有限公司 | Control method of power converter, power converter and photovoltaic system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106452137B (en) * | 2016-07-12 | 2018-08-07 | 艾思玛新能源技术（江苏）有限公司 | A kind of control method improving multichannel MPPT inverter transfer efficiencies |
-
2023
- 2023-11-09 CN CN202311499546.1A patent/CN117240057B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017148241A1 (en) * | 2016-02-29 | 2017-09-08 | 中兴通讯股份有限公司 | Inverter control method, device, and power generation system |
| CN114614663A (en) * | 2020-12-03 | 2022-06-10 | 台达电子企业管理（上海）有限公司 | Control method, auxiliary power supply of photovoltaic inverter and photovoltaic power generation system |
| CN216530687U (en) * | 2021-11-26 | 2022-05-13 | 深圳市正浩创新科技股份有限公司 | Photovoltaic power supply control circuit, photovoltaic power supply control device and power supply equipment |
| CN116131575A (en) * | 2023-01-13 | 2023-05-16 | 华为数字能源技术有限公司 | Power conversion apparatus and control method thereof |
| CN116800096A (en) * | 2023-08-24 | 2023-09-22 | 杭州禾迈电力电子股份有限公司 | Control method of power converter, power converter and photovoltaic system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117240057A (en) | 2023-12-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5081596B2 (en) | Power supply system | |
| US10374447B2 (en) | Power converter circuit including at least one battery | |
| CN103227475A (en) | Maximizing power in a photovoltaic distributed power system | |
| CN107785987B (en) | Online uninterrupted power supply | |
| JP2014131425A (en) | Power control device, power control method, program, and energy management system | |
| WO2012144358A1 (en) | Power supply device, control method for power supply device, and dc power supply system | |
| CN112868153B (en) | Converter, method and system applied to photovoltaic power generation system | |
| US7098558B2 (en) | Starting circuit for power-converting apparatus | |
| TW201020712A (en) | Frequency-varied incremental conductance maximum power point tracking controller and algorithm for PV converter | |
| KR100859495B1 (en) | Photovoltaic system using step-up converter | |
| KR101426696B1 (en) | Grid-connected module type photovoltaic power conversion apparatus | |
| CN117240057B (en) | Power converter, control method thereof and photovoltaic power generation system | |
| CN204046415U (en) | The quick startup control circuit of converter | |
| CN113258773A (en) | Power conversion system, power conversion device and control method thereof | |
| CN102130345A (en) | Fuel cell system and power supply management method thereof | |
| CN114337264B (en) | Boost conversion circuit, device and method | |
| CN112583279B (en) | Control method and system suitable for bidirectional isolation type DCDC converter | |
| CN105024542A (en) | Solar energy boost converter and control method thereof | |
| CN113794364A (en) | Power supply system and control method thereof | |
| WO2022206569A1 (en) | Optical storage direct-current coupling system and testing method therefor | |
| CN113261174A (en) | Photovoltaic converter group string, control method and system | |
| CN219871594U (en) | Aging circuit of multi-alternating-current output port energy storage inverter | |
| CN218771782U (en) | DC converter and grid-connected inverter | |
| CN219740026U (en) | Power supply circuit and energy storage system | |
| CN115149779B (en) | Drive power supply circuit and power conversion device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |