CN220570331U - Power supply conveying device, power supply conversion device and photovoltaic system - Google Patents
Power supply conveying device, power supply conversion device and photovoltaic system Download PDFInfo
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- CN220570331U CN220570331U CN202321786772.3U CN202321786772U CN220570331U CN 220570331 U CN220570331 U CN 220570331U CN 202321786772 U CN202321786772 U CN 202321786772U CN 220570331 U CN220570331 U CN 220570331U
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Abstract
The application provides a power supply conveying device, a power supply conversion device and a photovoltaic system; the power supply transmission device comprises a direct current bus, a power supply conversion circuit and a bus capacitor; the direct current bus is used for transmitting the output voltage of the photovoltaic module to a power grid; the power supply conversion circuit converts alternating voltage at one side of the power grid into direct voltage, and comprises a first output end and a second output end, wherein the first output end is connected to a positive direct current bus in the direct current buses, and the second output end is connected to a negative direct current bus of the direct current buses; the bus capacitor is connected between a positive DC bus and a negative DC bus in the DC buses. Above-mentioned scheme, power conversion circuit can charge for bus capacitance: when the photovoltaic system needs to be charged, the power grid alternating voltage is converted into direct voltage and is transmitted to two sides of the bus capacitor to charge the bus capacitor, a bypass circuit is not required to be arranged in the system, the power conversion circuit can be realized by using the existing device in the traditional photovoltaic system, the volume and the cost of the photovoltaic system are reduced, and the reliability of the photovoltaic system is improved.
Description
Technical Field
The disclosed embodiments of the present application relate to the field of power electronics technology, and more particularly, to a power supply delivery device, a power conversion device, and a photovoltaic system.
Background
In the photovoltaic system, a photovoltaic power generation assembly is connected with a power grid side through a bus, the bus close to the photovoltaic power generation assembly is a direct current bus, the direct current bus is connected to the power grid side through a three-phase alternating current bus after being connected to an alternating current-direct current conversion device, a bus capacitor is bridged between a positive direct current bus and a negative direct current bus, and each alternating current bus is provided with a bus switch; when the photovoltaic power generation assembly supplies power to the power grid side, the bus capacitor needs to be precharged.
In conventional photovoltaic systems, a bypass circuit is typically provided on an ac bus, the bypass circuit including a bypass resistor and a bypass switch, and when the bus capacitor needs to be precharged, the bypass switch and the bus switch on the ac bus are turned on, the bus capacitor can be precharged through the bypass circuit, and after the precharge of the bus capacitor is completed, the bypass circuit is turned off. However, the bypass circuit is bulky, costly, and has poor reliability, resulting in a bulky, costly, and poor reliability of the entire photovoltaic system.
Therefore, how to reduce the volume, cost and improve the reliability of the photovoltaic system is a current urgent problem to be solved.
Disclosure of Invention
According to the embodiment of the application, the application provides a power supply conveying device, a power supply conversion device and a photovoltaic system, so that the volume and the cost of the photovoltaic system are reduced, and the reliability of the photovoltaic system is improved.
According to one aspect of the present application, a power delivery apparatus for a photovoltaic system is disclosed, the apparatus comprising a dc bus, a power conversion circuit, and a bus capacitor; the direct current bus is used for conveying the output voltage of the photovoltaic module to a power grid; the power conversion circuit is used for converting alternating current voltage at one side of the power grid into direct current voltage, wherein the power conversion circuit comprises a first output end and a second output end, the first output end is used for being connected to a positive direct current bus in the direct current buses, and the second output end is connected to a negative direct current bus of the direct current buses; the bus capacitor is connected between the positive direct current bus and the negative direct current bus in the direct current buses; when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the power conversion circuit charges the bus capacitor; and when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at the power grid side, the power supply conversion circuit stops charging the bus capacitor.
By means of the scheme, the power conversion circuit can be used for charging the bus capacitor: when charging is needed, the power grid alternating voltage can be converted into direct voltage and then is transmitted to two sides of the bus capacitor to charge the bus capacitor, so that a bypass circuit is not needed to be arranged in the system, the power conversion circuit can be realized by using the existing device in the traditional photovoltaic system, and the volume and cost of the photovoltaic system are reduced, and the reliability of the photovoltaic system is improved.
The second aspect of the present application proposes a power conversion device, including a first output end, a second output end, and a ground end, and a dc conversion module, connected to a dc bus through the first output end and the second output end, and grounded through the ground end; when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the direct current conversion module charges the bus capacitor; and when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the direct current conversion module stops charging the bus capacitor, and/or when the difference between the grounding voltage of the positive direct current bus and the grounding voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the direct current conversion module generates compensation voltage between the second output end and the grounding end so that the difference between the grounding voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
The scheme can be used for charging the bus capacitor: when charging is needed, the alternating-current voltage of the power grid can be converted into direct-current voltage and then transmitted to two sides of the bus capacitor to charge the bus capacitor, so that a bypass circuit is not needed to be arranged in the system, the size and the cost of the photovoltaic system are reduced, and the reliability of the photovoltaic system is improved.
A third aspect of the present application proposes a photovoltaic system; the photovoltaic system comprises a photovoltaic module, a power grid and any power supply conveying device.
By means of the scheme, the power conversion circuit can be used for charging the bus capacitor: when charging is needed, the power grid alternating voltage can be converted into direct voltage and then is transmitted to two sides of the bus capacitor to charge the bus capacitor, so that a bypass circuit is not needed to be arranged in the system, the power conversion circuit can be realized by using the existing device in the traditional photovoltaic system, and the volume and cost of the photovoltaic system are reduced, and the reliability of the photovoltaic system is improved.
Drawings
The application will be further described with reference to the accompanying drawings and embodiments, in which:
FIG. 1 is a schematic circuit diagram of an embodiment of a photovoltaic system of the present application;
fig. 2 is a schematic circuit diagram of an embodiment of a power conversion device of the present application.
Detailed Description
In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions of the present application are described in further detail below with reference to the accompanying drawings and the detailed description.
In a photovoltaic system, bus capacitors are generally connected across positive and negative buses of a direct current bus, and before a photovoltaic module supplies power to a power grid, the bus capacitors need to be precharged so as to reduce damage to power equipment caused by larger current generated at the moment of circuit electrifying; in addition, after the photovoltaic system is used for a long time, the positive and negative bus voltages on the direct current bus are unequal to the ground voltage, so that larger leakage current is generated, and the service life of the photovoltaic module is further reduced.
In view of this, in order to precharge the bus capacitor before supplying power and to alleviate the problem of unequal voltages of the positive and negative buses to the ground, the existing photovoltaic system is connected to a bypass circuit on a three-phase ac bus of the power grid after the dc bus, the bypass circuit includes a bypass resistor and a bypass switch, when the bus capacitor needs to be precharged, the bypass switch is closed to form a precharge loop of the bus capacitor through one of the bypass circuit and the three-phase ac bus, the bypass circuit is opened after the precharge of the bus capacitor is completed, the three-phase ac bus is turned on, and then the precharge of the bus capacitor is completed before the photovoltaic module is supplied with power; and additionally arranging a set of switch power supply which is respectively connected to the positive direct current bus and the negative direct current bus so as to output compensation voltage when the positive direct current bus and the negative direct current bus are different in grounding voltage, so that the positive direct current bus and the negative direct current bus are equal in grounding voltage, and leakage current is prevented. However, because the bypass resistor and the bypass switch adopted in the bypass circuit need to bear larger current and voltage and break large current, the volume and the cost are extremely large, the reliability is not high, and the volume and the cost of the whole photovoltaic system are further increased due to the additionally configured switching power supply.
Accordingly, the present application provides a power supply device and a photovoltaic system, so as to at least reduce the volume and cost of the photovoltaic system and improve the reliability thereof.
It should be noted that, herein, references to "unequal" or "equal" at "the positive and negative bus voltages on the dc bus are unequal" or "the positive and negative dc bus voltages are equal" are understood by those skilled in the art to not mean that they need to be strictly unequal or equal in value, but may float within a certain acceptable range, for example, when the absolute value of the difference between the absolute values of the positive and negative dc bus voltages to ground is within 5% of the value of the normal dc bus voltage, the positive and negative dc bus voltages are considered to be equal to ground, otherwise the positive and negative dc bus voltages are considered to be unequal to ground.
Furthermore, it should be understood that references herein to "photovoltaic modules" may include photovoltaic panels.
Referring to fig. 1, fig. 1 is a schematic circuit diagram of an embodiment of a photovoltaic system of the present application; the photovoltaic system may include a photovoltaic module, a power grid, and a power delivery apparatus 100.
With continued reference to fig. 1, a power supply apparatus 100 according to the present disclosure may include a dc bus, a power conversion circuit 110, and a bus capacitor C1; the direct current bus is used for conveying the output voltage of the photovoltaic module to a power grid; the power conversion circuit 110 is configured to convert an ac voltage at a power grid side into a dc voltage, where the power conversion circuit 110 includes a first output end O1 and a second output end O2, the first output end O1 is configured to be connected to a positive dc bus vbus+ in the dc bus, and the second output end O2 is connected to a negative dc bus Vbus-of the dc bus; the bus capacitor C1 is connected between a positive direct current bus Vbus+ and a negative direct current bus Vbus-in the direct current buses; when the voltage of the bus capacitor C1 is lower than the peak value of the ac voltage at the power grid side, the power conversion circuit 110 charges the bus capacitor C1; when the voltage of the bus capacitor C1 is higher than the peak value of the ac voltage on the grid side, the power conversion circuit 110 stops charging the bus capacitor C1.
In the above-described aspect, the power conversion circuit 110 can be used to charge the bus capacitor C1 by the power conversion circuit 110: when charging is needed, the power grid alternating voltage can be converted into direct voltage and then is transmitted to two sides of the bus capacitor C1 to charge the bus capacitor C1, so that a bypass circuit is not needed to be arranged in the system, and the power conversion circuit 110 can be realized by using the existing device in the traditional photovoltaic system, thereby reducing the volume and cost of the photovoltaic system and improving the reliability of the photovoltaic system.
Further, in some embodiments, the power conversion circuit 110 further includes a ground (not labeled in the figure); when the difference between the ground voltage of the positive dc bus vbus+ and the ground voltage of the negative dc bus Vbus-in the dc buses exceeds the preset difference value, the power conversion circuit 110 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the ground voltages of the positive dc bus vbus+ and the negative dc bus Vbus-in the dc buses is smaller than the preset difference value.
Specifically, in some implementation scenarios, the preset difference value may be 5% of the normal voltage value of the bus, or other values, which are not limited in the present application; further, it will be understood by those skilled in the art that determining whether the voltages to ground of the positive and negative buses are "equal" may be determining whether the absolute values of the voltages to ground are "equal".
In some embodiments, the power conversion circuit 110 further includes a dc conversion module 111, where the dc conversion module 111 is connected to the dc bus through a first output terminal O1 and a second output terminal O2; the relevant pins of the control module 112 detect that the voltage of the bus capacitor C1 is lower than the peak value of the alternating voltage at one side of the power grid, and the corresponding control signal output pins of the control module 112 generate levels for driving the first switch S4 and the second switch S5, so that the first switch S4 is driven to be turned on, the second switch S5 is driven to be turned off, and the direct current conversion module 111 charges the bus capacitor C1; when the relevant pin of the control module 112 detects that the voltage of the bus capacitor C1 is higher than the peak value of the ac voltage at the power grid side, the control module 112 generates a corresponding level signal to drive the first switch S4 to be turned off and the second switch S5 to be turned on, so as to stop charging the bus capacitor C1.
In some embodiments, the dc conversion module 111 is also grounded through a ground; when the difference between the ground voltage of the positive dc bus vbus+ and the ground voltage of the negative dc bus Vbus-in the dc buses exceeds the preset difference value, the power conversion circuit 110 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the ground voltages of the positive dc bus vbus+ and the negative dc bus Vbus-in the dc buses is smaller than the preset difference value.
In some implementations, the dc conversion module 111 may include a dc converter, which may be implemented based on any one of a three-level topology, a forward topology, a buck-boost topology, a flyback topology, a half-bridge topology, a full-bridge topology, and the like, which is not limited in this application. It will be appreciated that a dc converter may be used to convert higher voltage and/or unstable dc power to lower voltage and/or stable dc power for subsequent use.
In some embodiments, the power conversion circuit 110 further includes a switch module; the switch module comprises a first switch S4 and a second switch S5, wherein a first output end O1 of the power conversion circuit 110 is connected with a positive direct current bus Vbus+ through the first switch S4, and a grounding end of the power conversion circuit 110 is grounded through the second switch S5; when the voltage of the bus capacitor C1 is lower than the peak value of the alternating voltage at one side of the power grid, the first switch S4 is turned on, the second switch S5 is turned off, and the power conversion circuit 110 charges the bus capacitor C1; when the voltage of the bus capacitor C1 is higher than the peak value of the ac voltage on the grid side, the power conversion circuit 110 stops charging the bus capacitor C1; and/or, when the difference between the voltage to ground of the positive dc bus vbus+ and the voltage to ground of the negative dc bus Vbus-in the dc buses exceeds the preset difference value, the power conversion circuit 110 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the voltages to ground of the positive dc bus vbus+ and the negative dc bus Vbus-in the dc buses is smaller than the preset difference value.
Specifically, in some implementation scenarios, the first switch S4 and the second switch S5 may be semiconductor controllable switching devices (such as metal oxide semiconductor field effect transistors, triodes, etc.), optical coupling devices, magnetic coupling devices (such as relays), etc., so that the first switch S4 and the second switch S5 can be turned on or off under the driving of the driving level received by the control terminal thereof.
For example, when the bus capacitor C1 needs to be precharged, the control end of the first switch S4 receives a driving level for driving the first switch S4 to be turned on, and the control end of the second switch S5 receives a driving level for driving the second switch S5 to be turned off, so that the first output end O1 and the second output end O2 of the power conversion circuit 110 are respectively connected to the positive electrode and the negative electrode of the bus capacitor C1, and the power conversion circuit 110 converts the ac power on the power grid side into dc power and outputs the dc power to the two ends of the bus capacitor C1 to charge the bus capacitor C1; when the voltage of the bus capacitor C1 is higher than the peak value of the ac voltage at the power grid side, the control end of the first switch S4 receives a driving level for driving the first switch S to turn off, so that the power conversion circuit 110 stops charging the bus capacitor C1, and the photovoltaic module starts to normally output the voltage to the power grid side.
For example, when the difference between the ground voltage of the positive dc bus vbus+ and the ground voltage of the negative dc bus vbus+ exceeds the preset difference value, the control terminal of the second switch S5 receives the driving level for driving the positive dc bus vbus+ to be turned on, and the control terminal of the first switch S4 receives the driving level for driving the negative dc bus Vbus to be turned off, so that the power conversion circuit 110 injects a compensation voltage into the negative dc bus Vbus to make the ground voltage of the negative dc bus vbus+ and the ground voltage of the positive dc bus vbus+ smaller than the preset difference value.
In some embodiments, the power conversion circuit 110 further includes a control module 112; the control module 112 is connected to the switch module and is used for controlling the on-off of the switch module; when the voltage of the bus capacitor C1 is lower than the peak value of the ac voltage at the power grid side, the control module 112 controls the first switch S4 to be turned on and the second switch S5 to be turned off, so that the power conversion circuit 110 charges the bus capacitor C1; when the voltage of the bus capacitor C1 is higher than the peak value of the ac voltage at the power grid side, the power conversion circuit 110 is controlled to stop charging the bus capacitor C1; and/or, when the difference between the voltage to ground of the positive dc bus vbus+ and the voltage to ground of the negative dc bus Vbus-in the dc buses exceeds the preset difference value, the power conversion circuit 110 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the voltages to ground of the positive dc bus vbus+ and the negative dc bus Vbus-in the dc buses is smaller than the preset difference value.
In some implementations, the control module 112 may include a micro control unit MCU for outputting various control level signals; the MCU can be connected to the first switch S4 and the second switch S5 through the first switch driving circuit S4_driver and the second switch driving circuit S5_driver respectively, and the MCU outputs control level signals to the first switch driving circuit S4_driver and the second switch driving circuit S5_driver so as to enable the MCU to output corresponding driving levels to drive the first switch S4 and the second switch S5 to be turned on or off; for example, the first and second switch driving circuits s4_driver and s5_driver may be driving circuits for driving the metal oxide semiconductor field effect transistor.
In some embodiments, the power conversion circuit 110 further includes a rectification module 113; the rectifying module 113 is connected to the power grid and power conversion circuit 110, and is configured to convert an ac voltage on the power grid side into a dc voltage and output the dc voltage to the power conversion circuit 110.
In some embodiments, the rectifying module 113 may include a rectifying device based on a rectifying bridge, where the rectifying manner may include any one of full-wave rectification, half-wave rectification, controllable rectification, uncontrollable rectification, single-phase rectification, three-phase rectification, and the like, and may be selected according to different usage scenarios, which is not limited in this application.
In some embodiments, the control module 112 may also be connected to the enable terminal EN of the dc conversion module 111, where the control module 112 can output a control level signal to control the dc conversion module 111 to start and stop.
In some embodiments, referring to fig. 1, the power conversion circuit may further include a first capacitor C2 and a second capacitor C3.
In some embodiments, the power delivery device further comprises an ac-dc conversion circuit, one end of which is connected to the dc bus and the other end of which is connected to the three-phase ac bus, for converting the output voltage of the photovoltaic module into an ac power for delivery to the grid.
In some embodiments, the power delivery apparatus further comprises a contactor module connected to the inverter circuit; when the alternating current output by the inverter circuit is identical in amplitude and phase with the alternating current on one side of the power grid, the contactor module is closed.
In some embodiments, the detection device may be configured to detect the amplitude and the phase of the ac power output by the inverter circuit and the ac power on the grid side, respectively, and generate a control level signal when the amplitude and the phase of the ac power output by the inverter circuit are the same, so as to drive the contactor module to be closed.
The contactor module comprises a first contactor S1, a second contactor S2 and a third contactor S3, and the first contactor, the second contactor and the third contactor are respectively arranged on each phase of the three-phase alternating current bus.
Referring to fig. 2, fig. 2 is a schematic circuit diagram of an embodiment of the power conversion device 200 of the present application; the power conversion device 200 includes a first output terminal O1, a second output terminal O2, and a ground terminal (not labeled in the figure), and a dc conversion module 111; the direct current conversion module 111 is connected to the direct current bus through a first output end O1 and a second output end O2 and grounded through a grounding terminal; when the voltage of the bus capacitor is lower than the peak value of the ac voltage at one side of the power grid, the dc conversion module 111 charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the ac voltage at the grid side, the dc conversion module 111 stops charging the bus capacitor, and/or when the difference between the ground voltage of the positive dc bus and the ground voltage of the negative dc bus in the dc buses exceeds the preset difference value, the dc conversion module 111 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the ground voltages of the positive dc bus and the negative dc bus in the dc buses is smaller than the preset difference value.
In some implementations, the dc conversion module 111 may include a dc converter, which may be implemented based on a three-level topology, a forward topology, a buck-boost topology, a flyback topology, a half-bridge topology, a full-bridge topology, and other circuit topologies, which are not limited in this application.
In some embodiments, the power conversion apparatus 200 further comprises a switch module; the switch module comprises a first switch S4 and a second switch S5, wherein a first output end O1 of the power conversion device 200 is connected with the positive direct current bus through the first switch S4, and a grounding end of the power conversion device 200 is grounded through the second switch S5; when the voltage of the bus capacitor is lower than the peak value of the ac voltage at one side of the power grid, the first switch S4 is turned on, the second switch S5 is turned off, and the power conversion device 200 charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating voltage at the power grid side, the power conversion device 200 stops charging the bus capacitor; and/or, when the difference between the ground voltage of the positive dc bus and the ground voltage of the negative dc bus exceeds the preset difference value, the power conversion device 200 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the ground voltages of the positive dc bus and the negative dc bus is smaller than the preset difference value.
Specifically, in some implementation scenarios, the first switch S4 and the second switch S5 may be semiconductor controllable switching devices (such as metal oxide semiconductor field effect transistors, triodes, etc.), optical coupling devices, magnetic coupling devices (such as relays), etc., so that the first switch S4 and the second switch S5 can be turned on or off under the driving of the driving level received by the control terminal thereof.
In some embodiments, the power conversion device 200 further includes a control module 112 connected to the switch module for controlling on/off of the switch module; when the voltage of the bus capacitor is lower than the peak value of the ac voltage at one side of the power grid, the control module 112 controls the first switch S4 to be turned on and the second switch S5 to be turned off, and the power conversion device 200 charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating voltage at the power grid side, the power conversion device 200 stops charging the bus capacitor; and/or, when the difference between the ground voltage of the positive dc bus and the ground voltage of the negative dc bus exceeds the preset difference value, the power conversion device 200 generates a compensation voltage between the second output terminal O2 and the ground terminal so that the difference between the ground voltages of the positive dc bus and the negative dc bus is smaller than the preset difference value.
In some implementations, the control module 112 may include a micro control unit MCU for outputting various control level signals; the MCU can be connected to the first switch S4 and the second switch S5 through the first switch S4 driving circuit S4_driver and the second switch S5 driving circuit S5_driver respectively, and the MCU outputs a control level signal to the first switch S4 driving circuit S4_driver and the second switch S5 driving circuit S5_driver so that the MCU outputs corresponding driving levels to drive the first switch S4 and the second switch S5 to be turned on or off; for example, the first switch S4 driving circuit s4_driver and the second switch S5 driving circuit s5_driver may be driving circuits for driving the metal oxide semiconductor transistor.
In some embodiments, the power conversion apparatus 200 further includes a rectifying module 113 connected between the power grid and the dc conversion module 111, and configured to convert an ac voltage on one side of the power grid into a dc voltage and output the dc voltage to the dc conversion module 111.
In some implementations, the rectifying module 113 may include a rectifying bridge-based device for rectifying, where a rectifying manner may include full-wave rectification, half-wave rectification, controllable rectification, uncontrollable rectification, single-phase rectification, and three-phase rectification, and may be selected according to different usage scenarios, which is not limited in this application.
In some embodiments, the control module 112 may also be connected to the enable terminal EN of the dc conversion module 111, where the control module 112 can output a control level signal to control the dc conversion module 111 to start and stop.
In some embodiments, the control module 112 may also be connected to the enable terminal EN of the dc conversion module 111, where the control module 112 can output a control level signal to control the dc conversion module 111 to start and stop.
In some embodiments, referring to fig. 2, the power conversion circuit may further include a first capacitor C2 and a second capacitor C3.
For example, when the bus capacitor needs to be precharged, the control end of the first switch S4 receives the driving level of the first switch S4 driving circuit s4_driver for driving the bus capacitor to be turned on, and the control end of the second switch S5 receives the driving level of the second switch S5 driving circuit s5_driver for driving the second switch S5_driver to be turned off, so that the first output end O1 and the second output end O2 of the power conversion device 200 are respectively connected to the positive electrode and the negative electrode of the bus capacitor, and the power conversion device 200 obtains direct current through the direct current conversion module 111 and outputs the direct current to the two ends of the bus capacitor to charge the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the ac voltage at the power grid side, the control end of the first switch S4 receives a driving level for driving the first switch S to turn off, so that the power conversion device 200 stops charging the bus capacitor, and the photovoltaic module starts to normally output voltage to the power grid side.
For example, when the difference between the ground voltage of the positive dc bus and the ground voltage of the negative dc bus exceeds the preset difference value, the control end of the second switch S5 receives the on driving level of the second switch S5 driving circuit s5_driver, and the control end of the first switch S4 receives the off driving level of the first switch S4 driving circuit s4_driver, so that the power conversion device 200 injects a compensation voltage into the negative dc bus through the dc conversion module 111 to make the ground voltage of the negative dc bus and the ground voltage of the positive dc bus smaller than the preset difference value.
Those skilled in the art will readily appreciate that many modifications and variations are possible in the device and method while maintaining the teachings of the present application. Accordingly, the above disclosure should be viewed as limited only by the scope of the appended claims.
Claims (12)
1. A power delivery apparatus for a photovoltaic system, comprising:
the direct current bus is used for conveying the output voltage of the photovoltaic module to a power grid;
the power supply conversion circuit is used for converting the alternating current voltage at one side of the power grid into direct current voltage, wherein the power supply conversion circuit comprises a first output end and a second output end, the first output end is used for being connected to a positive direct current bus in the direct current buses, and the second output end is connected to a negative direct current bus of the direct current buses;
a bus capacitor connected between the positive dc bus and the negative dc bus of the dc buses;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the power conversion circuit charges the bus capacitor; and when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at the power grid side, the power supply conversion circuit stops charging the bus capacitor.
2. The power delivery apparatus of claim 1, wherein the power conversion circuit further comprises a ground terminal;
when the difference between the voltage to ground of the positive direct current bus and the voltage to ground of the negative direct current bus in the direct current buses exceeds a preset difference value, the power conversion circuit generates a compensation voltage between the second output end and the grounding end so that the difference between the voltage to ground of the positive direct current bus and the voltage to ground of the negative direct current bus in the direct current buses is smaller than the preset difference value.
3. The power supply delivery apparatus according to claim 2, wherein the power supply conversion circuit further comprises:
the direct current conversion module is connected to the direct current bus through the first output end and the second output end;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the direct current conversion module charges the bus capacitor; and when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the direct current conversion module stops charging the bus capacitor.
4. A power delivery apparatus as claimed in claim 3, wherein the dc conversion module is grounded via the ground;
when the difference between the voltage to ground of the positive direct current bus and the voltage to ground of the negative direct current bus in the direct current buses exceeds a preset difference value, the direct current conversion module generates a compensation voltage between the second output end and the grounding end so that the difference between the voltage to ground of the positive direct current bus and the voltage to ground of the negative direct current bus in the direct current buses is smaller than the preset difference value.
5. The power supply delivery apparatus according to claim 2, wherein the power supply conversion circuit further comprises:
the switch module comprises a first switch and a second switch, wherein the first output end of the power conversion circuit is connected with the positive direct current bus through the first switch, and the grounding end of the power conversion circuit is grounded through the second switch;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the first switch is turned on, the second switch is turned off, and the power conversion circuit charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the power supply conversion circuit stops charging the bus capacitor;
and/or the number of the groups of groups,
when the difference between the ground voltage of the positive direct current bus and the ground voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the power conversion circuit generates a compensation voltage between the second output end and the ground end so that the difference between the ground voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
6. The power delivery apparatus of claim 5, wherein the power conversion circuit further comprises:
the control module is connected to the switch module and used for controlling the on-off of the switch module;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the control module controls the first switch to be turned on and the second switch to be turned off, and the power conversion circuit charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating voltage at one side of the power grid, the control module controls the first switch to be turned off, and the power supply conversion circuit stops charging the bus capacitor;
and/or the number of the groups of groups,
when the difference between the ground voltage of the positive direct current bus and the ground voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the power conversion circuit generates a compensation voltage between the second output end and the ground end so that the difference between the ground voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
7. The power delivery apparatus of claim 3, wherein the power conversion circuit further comprises:
and the rectification module is connected to the power grid and the direct current conversion module and is used for converting the alternating current voltage at one side of the power grid into direct current voltage and outputting the direct current voltage to the direct current conversion module.
8. A power conversion device is characterized by comprising a first output end, a second output end and a grounding end, and the power conversion device comprises a power conversion circuit,
the direct current conversion module is connected to the direct current bus through the first output end and the second output end and grounded through the grounding end; when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the direct current conversion module charges the bus capacitor; and when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the direct current conversion module stops charging the bus capacitor, and/or when the difference between the grounding voltage of the positive direct current bus and the grounding voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the direct current conversion module generates compensation voltage between the second output end and the grounding end so that the difference between the grounding voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
9. The apparatus as recited in claim 8, further comprising:
the switch module comprises a first switch and a second switch, wherein the first output end of the power conversion device is connected with the positive direct current bus through the first switch, and the grounding end of the power conversion device is grounded through the second switch;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the first switch is turned on, the second switch is turned off, and the power conversion device charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the power conversion device stops charging the bus capacitor;
and/or the number of the groups of groups,
when the difference between the ground voltage of the positive direct current bus and the ground voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the power conversion device generates a compensation voltage between the second output end and the ground end so that the difference between the ground voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
10. The apparatus as recited in claim 9, further comprising:
the control module is connected to the switch module and used for controlling the on-off of the switch module;
when the voltage of the bus capacitor is lower than the peak value of the alternating voltage at one side of the power grid, the control module controls the first switch to be turned on and the second switch to be turned off, and the power conversion device charges the bus capacitor; when the voltage of the bus capacitor is higher than the peak value of the alternating current voltage at one side of the power grid, the power conversion device stops charging the bus capacitor;
and/or the number of the groups of groups,
when the difference between the ground voltage of the positive direct current bus and the ground voltage of the negative direct current bus in the direct current buses exceeds a preset difference value, the power conversion device generates a compensation voltage between the second output end and the ground end so that the difference between the ground voltages of the positive direct current bus and the negative direct current bus in the direct current buses is smaller than the preset difference value.
11. The apparatus as recited in claim 8, further comprising:
and the rectification module is connected between the power grid and the direct current conversion module and is used for converting the alternating current voltage at one side of the power grid into direct current voltage and outputting the direct current voltage to the direct current conversion module.
12. A photovoltaic system comprising a photovoltaic module, a power grid, and a power supply delivery apparatus according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321786772.3U CN220570331U (en) | 2023-07-07 | 2023-07-07 | Power supply conveying device, power supply conversion device and photovoltaic system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321786772.3U CN220570331U (en) | 2023-07-07 | 2023-07-07 | Power supply conveying device, power supply conversion device and photovoltaic system |
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| Publication Number | Publication Date |
|---|---|
| CN220570331U true CN220570331U (en) | 2024-03-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321786772.3U Active CN220570331U (en) | 2023-07-07 | 2023-07-07 | Power supply conveying device, power supply conversion device and photovoltaic system |
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| Country | Link |
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| CN (1) | CN220570331U (en) |
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- 2023-07-07 CN CN202321786772.3U patent/CN220570331U/en active Active
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