CN219513804U

CN219513804U - Photovoltaic inverter and auxiliary power supply device

Info

Publication number: CN219513804U
Application number: CN202320205089.XU
Authority: CN
Inventors: 黄瑞; 张骕骦; 李随军; 郭红强; 胡方
Original assignee: Sungrow Power Supply Co Ltd
Current assignee: Sungrow Power Supply Co Ltd
Priority date: 2023-01-31
Filing date: 2023-01-31
Publication date: 2023-08-11
Anticipated expiration: 2033-01-31

Abstract

The utility model discloses a photovoltaic inverter and an auxiliary power supply device, wherein the photovoltaic inverter comprises an inversion unit, a direct current bus, an auxiliary power supply and a control device, wherein the direct current bus is connected with the direct current side of the inversion unit, and is connected with a bus capacitor which is used for starting the inversion unit when reaching a preset voltage; the control device is electrically connected with the inversion unit and the auxiliary power supply respectively and is used for controlling one of the positive electrode output end and the negative electrode output end of the auxiliary power supply to be connected to the positive electrode and the negative electrode of the bus capacitor when receiving the reverse PID power supply starting signal, and the other is grounded; when an SVG power starting signal is received, controlling the positive electrode output end of the auxiliary power supply to be electrically connected with the positive electrode of the bus capacitor, and controlling the negative electrode output end of the auxiliary power supply to be electrically connected with the negative electrode of the bus capacitor; so that the auxiliary power supply charges the bus capacitor to a preset voltage and then starts the inversion unit. The method is used for solving the problems that SVG starting is limited by time and the development cost of the whole machine is high.

Description

Photovoltaic inverter and auxiliary power supply device

Technical Field

The utility model relates to the technical field of electronic power, in particular to a photovoltaic inverter and an auxiliary power supply device.

Background

Generally, when a power grid has reactive power supplementing requirements, the power grid needs to be supplemented with reactive power to realize the function of SVG (Static Var Generator ), the SVG takes a high-power voltage type photovoltaic inverter as a core, and the required reactive power is quickly absorbed or emitted by adjusting the amplitude and the phase of the output voltage of the photovoltaic inverter, so that the purpose of quickly and dynamically adjusting the reactive power is realized.

The prior photovoltaic inverter generally adopts the following two schemes to realize SVG functions:

scheme one: when the bus capacitor is still powered, the inverter unit is led to enter SVG in advance;

scheme II: a set of SVG power supply is developed, power is taken from an alternating current side such as a power grid and the like, so that a bus capacitor is charged, and an SVG function is realized by starting an inversion unit.

However, both of the above solutions have drawbacks. If the SVG can not be accessed when the bus capacitor is electrified or the fault is restarted, the SVG can not be started once the scheme is adopted, the SVG function can be realized again only when the bus capacitor is electrified in the daytime, and the SVG function is limited by time; although the SVG power supply of the second scheme can charge the bus capacitor at any time, the SVG power supply is redeveloped, so that the whole machine cost is high.

Disclosure of Invention

One of the main purposes of the utility model is to provide a photovoltaic inverter which is used for solving the problems that SVG starting is limited by time and the development cost of the whole machine is high.

To achieve the above object, the present utility model provides a photovoltaic inverter comprising:

an inversion unit;

the direct current bus is connected with the direct current side of the inversion unit, and is connected with a bus capacitor which is used for starting the inversion unit when reaching a preset voltage;

an auxiliary power supply having a positive output and a negative output; and

the control device is electrically connected with the inversion unit and the auxiliary power supply respectively and is used for controlling one of a positive electrode output end and a negative electrode output end of the auxiliary power supply to be connected to the positive electrode and the negative electrode of the bus capacitor when receiving an inverse PID power supply starting signal, and the other is grounded so that the auxiliary power supply charges the bus capacitor to a preset voltage and then starts the inversion unit; when an SVG power starting signal is received, the positive electrode output end of the auxiliary power supply is controlled to be electrically connected with the positive electrode of the bus capacitor, the negative electrode output end of the auxiliary power supply is electrically connected with the negative electrode of the bus capacitor, and after the auxiliary power supply charges the bus capacitor to a preset voltage, the inversion unit is started.

In an embodiment, the control device includes a controller and a switch switching circuit, where the controller is configured to control the switch switching circuit to connect one of a positive output end and a negative output end of the auxiliary power supply to a positive electrode and a negative electrode of the bus capacitor when receiving an inverse PID power supply start signal, and the other is grounded, so that the auxiliary power supply starts the inverter unit after charging the bus capacitor to a preset voltage;

the controller is further used for controlling the switch switching circuit to electrically connect the positive electrode output end of the auxiliary power supply with the positive electrode of the bus capacitor when the SVG power supply starting signal is received, and the negative electrode output end of the auxiliary power supply is electrically connected with the negative electrode of the bus capacitor so that the auxiliary power supply charges the bus capacitor to a preset voltage and then starts the inversion unit.

In an embodiment, the switch switching circuit includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch, where the first switch, the sixth switch and the third switch are sequentially connected in series, a first end of the first switch and a first end of the second switch are respectively connected with an anode output end of the auxiliary power supply, a second end of the second switch is grounded, a first end of the third switch, a first end of the fourth switch and a first end of the fifth switch are respectively connected with an anode output end of the auxiliary power supply, a second end of the fourth switch is grounded, a second end of the third switch, a second end of the fifth switch and a second end of the sixth switch are respectively connected with an anode of the bus capacitor, and a second end of the first switch and a second end of the third switch are respectively connected with an anode of the bus capacitor.

In an embodiment, the dc side of the inverter unit is connected to a photovoltaic module, when the photovoltaic module is a P-type panel, the controller controls the first switch, the fourth switch and the sixth switch to be turned on, and controls the second switch, the third switch and the fifth switch to be turned off, so that the positive output end of the auxiliary power supply charges the positive and negative poles of the bus capacitor, and the negative output end of the auxiliary power supply is grounded.

In an embodiment, the dc side of the inverter unit is connected to a photovoltaic module, when the photovoltaic module is an N-type panel, the controller controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch, the fifth switch and the sixth switch to be turned off, so that the negative output end of the auxiliary power supply charges the positive and negative poles of the bus capacitor, and the positive output end of the auxiliary power supply is grounded.

In an embodiment, the switch switching circuit further includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, wherein the second end of the first switch is connected with the positive electrode of the bus capacitor through the first diode, the second end of the third switch is connected with the positive electrode of the bus capacitor through the fourth diode, the second diode and the third diode are connected between the second end of the first switch and the first end of the sixth switch, and the second end of the third switch is connected with the negative electrode of the bus capacitor through the sixth diode and the fifth diode.

In an embodiment, the auxiliary power supply has a first output terminal group and a second output terminal group, each of which has the positive output terminal and the negative output terminal;

one of the positive electrode output end and the negative electrode output end of the first output end group is connected with the positive electrode and the negative electrode of the bus capacitor, and the other is grounded;

the positive electrode output end of the second output end group is electrically connected with the positive electrode of the bus capacitor, and the negative electrode output end of the second output end group is electrically connected with the negative electrode of the bus capacitor;

the control device is used for controlling the first output end group to output voltage when receiving an inverse PID power supply starting signal; and when the SVG power starting signal is received, controlling the second output end group to output voltage.

In an embodiment, the control device includes a controller and a switch switching circuit, where the switch switching circuit includes a first diode, a second diode, and a third diode, the positive output end of the first output end group is connected to the anode of the first diode and the anode of the second diode, the cathode of the first diode is connected to the positive electrode of the bus capacitor, the cathode of the second diode is connected to the anode of the third diode, the cathode of the third diode is connected to the negative electrode of the bus capacitor, and the negative output end of the first output end group is grounded.

In one embodiment, the input of the auxiliary power source is powered from the ac side.

The second main objective of the present utility model is to provide an auxiliary power device for solving the problem that the starting of SVG is limited by time and the development cost of the whole machine is high.

In order to achieve the above object, the present utility model provides an auxiliary power supply device applied to a photovoltaic inverter, the photovoltaic inverter comprising an inverter unit and a dc bus, the dc bus being connected to a dc side of the inverter unit, a bus capacitor being connected to the dc bus, the bus capacitor being configured to start the inverter unit when a preset voltage is reached; the auxiliary power supply device comprises an auxiliary power supply and a switch switching circuit, wherein the auxiliary power supply is provided with a positive electrode output end and a negative electrode output end;

when receiving an inverse PID power supply starting signal, the switch switching circuit connects one of the positive electrode output end and the negative electrode output end of the auxiliary power supply to the positive electrode and the negative electrode of the bus capacitor, and the other is grounded so as to charge the bus capacitor to a preset voltage for starting the inversion unit;

when an SVG power starting signal is received, the switch switching circuit electrically connects the positive electrode output end of the auxiliary power supply with the positive electrode of the bus capacitor, and the negative electrode output end of the auxiliary power supply is electrically connected with the negative electrode of the bus capacitor, so that the bus capacitor is charged to a preset voltage for starting the inversion unit.

In one embodiment, the DC side of the inversion unit is connected with a photovoltaic module,

when the photovoltaic module is a P-type battery plate, the positive electrode output end of the auxiliary power supply charges the positive electrode and the negative electrode of the bus capacitor, and the negative electrode output end of the auxiliary power supply is grounded;

when the photovoltaic module is an N-type battery plate, the negative electrode output end of the auxiliary power supply charges the positive electrode and the negative electrode of the bus capacitor, and the positive electrode output end of the auxiliary power supply is grounded.

In order to achieve the above object, the present utility model further provides an auxiliary power supply device applied to a photovoltaic inverter, the photovoltaic inverter including an inverter unit and a dc bus, the dc bus being connected to a dc side of the inverter unit, a bus capacitor being connected to the dc bus, the bus capacitor being configured to start the inverter unit when a preset voltage is reached; the auxiliary power supply device comprises an auxiliary power supply, wherein the auxiliary power supply is provided with a first output end group and a second output end group, and the first output end group and the second output end group are respectively provided with an anode output end and a cathode output end;

one of the positive electrode output end and the negative electrode output end of the first output end group is used for connecting the positive electrode and the negative electrode of the bus capacitor, and the other is grounded;

The positive electrode output end of the second output end group is used for being electrically connected with the positive electrode of the bus capacitor, and the negative electrode output end of the second output end group is used for being electrically connected with the negative electrode of the bus capacitor;

the first output end group is used for outputting voltage when receiving an inverse PID power supply starting signal; the second output terminal group is used for outputting voltage when receiving the SVG power starting signal.

when the photovoltaic module is a P-type battery plate, the positive electrode output end of the first output end group charges the positive electrode and the negative electrode of the bus capacitor, and the negative electrode output end of the first output end group is grounded;

when the photovoltaic module is an N-type battery plate, the negative electrode output end of the second output end group charges the positive electrode and the negative electrode of the bus capacitor, and the positive electrode output end of the second output end group is grounded.

Compared with the prior art, the utility model has the following beneficial effects:

1. the auxiliary power supply is controlled by the control device to charge the bus capacitor, the inversion unit is started when the auxiliary power supply is charged to a preset voltage, the SVG function is started at any time by charging the bus capacitor at any time, the problem that the SVG starting is limited by time is effectively solved, and the problem that the generated energy is wasted when the SVG function is started when the direct current bus is still powered can be avoided;

2. When receiving an inverse PID power supply starting signal, the control device controls one of the positive electrode output end and the negative electrode output end of the auxiliary power supply to be connected to the positive electrode and the negative electrode of the bus capacitor, and the other is grounded, so that after the auxiliary power supply charges the bus capacitor to a preset voltage, the inversion unit is started, the SVG function is realized by starting the inversion unit, and the problem that the SVG realization is limited by time is solved; when an SVG power supply starting signal is received, controlling the positive electrode output end of the auxiliary power supply to be electrically connected with the positive electrode of the bus capacitor, and the negative electrode output end of the auxiliary power supply to be electrically connected with the negative electrode of the bus capacitor, so that after the auxiliary power supply charges the bus capacitor to a preset voltage, starting the inversion unit, realizing the SVG function by starting the inversion unit, and solving the problem that the SVG realization is limited by time; the need of additionally developing and adding an SVG power supply device is avoided, and the cost of the whole machine is effectively reduced;

3. when receiving an inverse PID power supply starting signal, the auxiliary power supply charges a bus capacitor by lifting a common mode voltage to the ground of the direct current side; when receiving an SVG power starting signal, the auxiliary power supply charges the bus capacitor by lifting the voltage of the bus capacitor; for eliminating the surge current.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic functional block diagram of an embodiment of a photovoltaic inverter of the present utility model;

FIG. 2 is a circuit diagram of an embodiment of a photovoltaic inverter of the present utility model;

fig. 3 is a circuit diagram of another embodiment of the photovoltaic inverter of the present utility model;

in the figure: 100. an auxiliary power supply device; 101. an auxiliary power supply; 102. a switch switching circuit; 201. an inversion unit; 202. a direct current bus; 2021. a bus capacitor; 203. a control device; 204. a sampling circuit; 300. a photovoltaic module; 400. and (3) a power grid.

The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that, if all the directional indicators in the embodiments of the present utility model are only used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture, if the specific posture is changed, the directional indicators are correspondingly changed.

If the description of "first", "second", etc. in this disclosure is for descriptive purposes only, it is not to be construed as indicating or implying a relative importance thereof or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. If the description of "a and/or B" is referred to in the present utility model, it means that either scheme a or scheme B is included, or both scheme a and scheme B are included. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The utility model provides a photovoltaic inverter and an auxiliary power supply device 100.

Referring to fig. 1 to 3, the present utility model provides a photovoltaic inverter including an inverter unit 201, a dc bus 202, an auxiliary power source 101, and a control device 203. Wherein,,

the dc bus 202 is connected to a dc side of the inverter unit 201, a bus capacitor 2021 is connected to the dc bus 202, and the bus capacitor 2021 is used to start the inverter unit 201 when a preset voltage is reached;

the auxiliary power supply 101 has a positive output terminal and a negative output terminal;

the control device 203 is electrically connected to the inverter unit 201 and the auxiliary power supply 101, and is configured to control one of the positive output terminal and the negative output terminal of the auxiliary power supply 101 to be connected to the positive electrode and the negative electrode of the bus capacitor 2021 when receiving an anti-PID power supply start signal, and the other is grounded, so that the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, and then starts the inverter unit 201; when receiving the SVG power supply start signal, the positive output end of the auxiliary power supply 101 is controlled to be electrically connected with the positive electrode of the bus capacitor 2021, and the negative output end of the auxiliary power supply 101 is electrically connected with the negative electrode of the bus capacitor 2021, so that the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, and then the inverter unit 201 is started.

Optionally, the auxiliary power supply 101 includes a switching power supply, and the required output voltage is obtained through switching transformation, and the switching power supply may be a non-isolated topology structure such as Buck, boost, buck-Boost, sepic, or an isolated topology structure such as Flyback, forward, push-Pull, half-Bridge.

The control device 203 may be a single chip microcomputer or a microcontroller. When the SVG power function is needed, the switch power supply is output to the positive and negative positions of the bus capacitor 2021 to charge the bus capacitor; when the reverse PID power supply function is needed, the switching power supply is output to the positive electrode and the negative electrode of the bus capacitor 2021 to the ground, and the common mode voltage of the bus to the ground is lifted, so that multiplexing of the switching power supply is realized, and the output voltage of the auxiliary power supply is controlled by a control device.

Since the open circuit voltage and the reduction of the power generation efficiency occur when the dc power supply provided on the dc side such as the photovoltaic module 300 is operated at a negative potential or a positive potential higher than the ground, that is, the occurrence of the potential induced degradation (PID, potential Induced Degradation) phenomenon is caused, it is necessary to eliminate or reduce the positive potential or the negative potential to the ground on the dc side, that is, the influence of the PID effect is reduced to ensure the photovoltaic power generation efficiency.

When receiving the reverse PID power supply start signal, the auxiliary power supply 101 may be used as a reverse PID power supply, and applies the output voltage between the positive and negative electrodes of the bus capacitor 2021 and the ground, and by raising the common mode voltage to the ground on the dc side, the battery polarization phenomenon is eliminated, so as to charge the bus capacitor 2021, thereby realizing reverse PID repair or PID protection of the battery panel.

In a general SVG power supply, when the voltage of the dc bus 202 is low or no power is applied, the dc bus voltage is raised, so that the inverter can generate reactive power smoothly.

When receiving the SVG power supply start signal, the auxiliary power supply 101 may be used as an SVG power supply, apply the output voltage to the positive and negative electrodes of the bus capacitor 2021, and charge the bus capacitor 2021 by lifting the voltage of the bus capacitor 2021, so as to prepare for the SVG function.

It should be noted that, when the auxiliary power supply 101 according to the present application receives the anti-PID power supply start signal, the anti-PID power supply may be used to charge the bus capacitor 2021, that is, the bus capacitor 2021 is charged by raising the common mode voltage to the ground on the dc side, and other power supply components, power supply devices, power supply circuits, etc. that may charge the bus capacitor 2021 in this way are included in the scope of the auxiliary power supply 101 according to the present application.

Similarly, when the auxiliary power supply 101 receives the SVG power supply start signal, it can be used as the SVG power supply to charge the bus capacitor 2021, that is, by raising the voltage of the bus capacitor 2021 to charge the bus capacitor 2021, other power supply components, power supply devices, power supply circuits, etc. that can charge the bus capacitor 2021 in this way are included in the scope of the auxiliary power supply 101 according to the present utility model.

The circuit for implementing the anti-PID power supply function and the SVG power supply function of the auxiliary power supply 101 and the components thereof according to the present utility model may be integrated in the same circuit, the same circuit board member, or integrated in the same auxiliary power supply device by dividing the functional area, etc., and may be specifically set according to actual needs, which is not limited herein.

The auxiliary power supply 101 is controlled by the control device 203 to charge the bus capacitor 2021, and the inverter unit 201 is started when the auxiliary power supply is charged to a preset voltage, so that the SVG function is started at any time by charging the bus capacitor 2021 at any time, the problem that the SVG function is limited by time is effectively solved, and the problem that the generated energy is wasted when the SVG function is started when the direct current bus is still powered can be avoided.

When receiving the reverse PID power supply starting signal, the control device 203 controls one of the positive output end and the negative output end of the auxiliary power supply 101 to be connected to the positive electrode and the negative electrode of the bus capacitor 2021 according to the difference of the P-type battery plate, the N-type battery plate and the like, and the other is grounded, so that after the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, the inverter unit 201 is started, the SVG function is realized by starting the inverter unit 201, and the problem that the SVG function is limited by time is solved; when an SVG power starting signal is received, the positive electrode output end of the auxiliary power supply 101 is controlled to be electrically connected with the positive electrode of the bus capacitor 2021, the negative electrode output end of the auxiliary power supply 101 is electrically connected with the negative electrode of the bus capacitor 2021, so that after the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, the inverter unit 201 is started, the SVG function is realized by starting the inverter unit 201, and the problem that the SVG function is limited by time is solved; the need of additionally developing and adding an SVG power supply device is avoided, and the cost of the whole machine is effectively reduced.

When receiving the reverse PID power supply starting signal, the auxiliary power supply 101 charges the bus capacitor 2021 by lifting the common mode voltage to ground on the DC side; upon receiving the SVG power start signal, the auxiliary power supply 101 charges the bus capacitor 2021 by raising the voltage of the bus capacitor 2021; for eliminating the surge current.

In an embodiment, the control device 203 includes a controller and a switch switching circuit 102, where the controller is configured to control, when receiving an anti-PID power supply start signal, the switch switching circuit 102 to connect one of the positive output terminal and the negative output terminal of the auxiliary power supply 101 to the positive and negative electrodes of the bus capacitor 2021, and the other is grounded, so that after the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, the inverter unit 201 is started;

the controller is further configured to control the switch switching circuit 102 to electrically connect the positive output terminal of the auxiliary power supply 101 with the positive electrode of the bus capacitor 2021 when receiving an SVG power supply start signal, and electrically connect the negative output terminal of the auxiliary power supply 101 with the negative electrode of the bus capacitor 2021, so that the auxiliary power supply 101 charges the bus capacitor 2021 to a preset voltage, and then starts the inverter unit 201.

Optionally, the switch switching circuit 102 includes a switch assembly operable to generate a start signal when triggered to start or wake up the auxiliary power supply 101; the switch component is also used for generating an inverse PID power supply starting signal or an SVG power supply starting signal when triggered, and specifically outputting the inverse PID power supply starting signal or the SVG power supply starting signal alternatively, and is used for outputting the inverse PID power supply starting signal when the inverse PID power supply function is required to be realized and outputting the SVG power supply starting signal when the SVG power supply function is required to be realized; the switch-and-switch circuit 102 may also be used to complete the switching of the anti-PID power-on signal and the SVG power-on signal. Of course, according to practice, it is not excluded to arrange the switching circuit as a gating circuit integrated in the control device for accomplishing the switching of the anti-PID power supply function and the SVG power supply function; the control device may also include a sampling circuit, and the switch switching circuit is automatically started and switched to an anti-PID power supply function or an SVG power supply function according to a sampling result.

According to the actual implementation, the control device 203 may optionally preset a start time, so as to implement the anti-PID power function or the SVG power function at night and implement the anti-PID power function at daytime according to the preset start time.

Optionally, the bus capacitor 2021 includes a first bus capacitor and a second bus capacitor sequentially connected in series, where the first bus capacitor and the second bus capacitor are connected in series between a positive output terminal and a negative output terminal of the dc side of the dc power supply.

In one embodiment, to facilitate switching of the anti-PID power function and the SVG power function, the switching circuit 102 includes a first switch K1, a second switch K2, a third switch K3, a fourth switch K4, a fifth switch K5 and a sixth switch K6,

the first switch K1, the sixth switch K6 and the third switch K3 are sequentially connected in series, the first end of the first switch K1 and the first end of the second switch K2 are respectively connected with the positive output end of the auxiliary power supply 101, the second end of the second switch K2 is grounded,

the first end of the third switch K3, the first end of the fourth switch K4 and the first end of the fifth switch K5 are respectively connected to the negative output end of the auxiliary power supply 101, the second end of the fourth switch K4 is grounded,

the second end of the third switch K3, the second end of the fifth switch K5 and the second end of the sixth switch K6 are respectively connected to the negative electrode of the bus capacitor 2021,

the second end of the first switch K1 and the second end of the third switch K3 are respectively connected to the positive electrode of the bus capacitor 2021.

Optionally, relays may be used for the first switch K1, the second switch K2, the third switch K3, the fourth switch K4, the fifth switch K5, and the sixth switch K6.

The switch switching circuit shown in the utility model can be also suitable for eliminating the positive potential or negative potential of the photovoltaic module to the ground when different photovoltaic modules are connected on the direct current side.

In an embodiment, the dc side of the inverter unit 201 is connected to the photovoltaic module 300, and when the photovoltaic module 300 is a P-type panel, the controller controls the first switch K1, the fourth switch K4, and the sixth switch K6 to be turned on, and controls the second switch K2, the third switch K3, and the fifth switch K5 to be turned off, so that the positive output end of the auxiliary power supply 101 charges the positive and negative poles of the bus capacitor 2021, and the negative output end of the auxiliary power supply 101 is grounded.

In an embodiment, the dc side of the inverter unit 201 is connected to the photovoltaic module 300, when the photovoltaic module 300 is an N-type panel, the controller controls the second switch K2 and the third switch K3 to be turned on, and controls the first switch K1, the fourth switch K4, the fifth switch K5 and the sixth switch K6 to be turned off, so that the negative output end of the auxiliary power supply 101 charges the positive and negative poles of the bus capacitor 2021, and the positive output end of the auxiliary power supply 101 is grounded.

The dc side of the inverter unit 201 is connected to the photovoltaic module 300, when the photovoltaic module 300 is a P-type panel, the positive voltage to ground of the P-type panel is lifted to charge the bus capacitor 2021, and when the photovoltaic module 300 is an N-type panel, the negative voltage to ground of the N-type panel is lifted to charge the bus capacitor 2021, so as to eliminate the positive potential or the negative potential of the photovoltaic module 300 to ground, and improve the power generation capacity of the photovoltaic module 300.

In one embodiment, the switching circuit 102 further includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6,

the second end of the first switch K1 is connected to the positive electrode of the bus capacitor 2021 through the first diode D1, the second end of the third switch K3 is connected to the positive electrode of the bus capacitor 2021 through the fourth diode D4, the second diode D2 and the third diode D3 are connected between the second end of the first switch K1 and the first end of the sixth switch K6, and the second end of the third switch K3 is connected to the negative electrode of the bus capacitor 2021 through the sixth diode D6 and the fifth diode D5.

Specifically, the second end of the first switch K1 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the anode of the bus capacitor 2021;

A second end of the first switch K1 is connected to an anode of the second diode D2, a cathode of the second diode D2 is connected to an anode of the third diode D3, a cathode of the third diode D3 is connected to a first end of the sixth switch K6, and a second end of the sixth switch K6 is connected to a cathode of the busbar capacitor 2021;

a first end of the fifth switch K5 is connected to the negative output end of the auxiliary power supply 101 through a resistor R3, and a second end of the fifth switch K5 is connected to the negative electrode of the bus capacitor 2021;

the first end of the first switch K1 and the first end of the second switch K2 are respectively connected with the positive output end of the auxiliary power supply 101, and the second end of the second switch K2 is grounded; alternatively, a current limiting component may be provided, where the current limiting component may use a current limiting resistor, and the second end of the second switch K2 is grounded through the current limiting resistor R1. The current limiting resistor is arranged to avoid the generation of impact current.

The first end of the third switch K3 and the first end of the fourth switch K4 are respectively connected to the negative output end of the auxiliary power supply 101, and the second end of the fourth switch K4 is grounded, optionally, the second end of the second switch K2 is grounded through a current limiting resistor R2.

A second end of the third switch K3 is connected to an anode of the sixth diode D6, a cathode of the sixth diode D6 is connected to an anode of the fifth diode D5, and a cathode of the fifth diode D5 is connected to a cathode of the bus capacitor 2021;

the second end of the third switch K3 is connected to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the anode of the bus capacitor 2021.

As an example, the control device 203, upon receiving the anti-PID power enable signal:

if the photovoltaic module 300 is a P-type panel, the controller controls the first switch K1, the fourth switch K4 and the sixth switch K6 to be turned on, controls the second switch K2, the third switch K3 and the fifth switch K5 to be turned off, the negative output end of the auxiliary power supply 101 is grounded, and the positive output end of the auxiliary power supply 101 lifts the voltage to the ground through the first diode D1, the second diode D2 and the third diode D3 to charge the bus capacitor 2021 to a preset voltage, and then starts the inverter unit;

if the photovoltaic module 300 is an N-type battery board, the controller controls the second switch K2 and the third switch K3 to be turned on, and controls the first switch K1, the fourth switch K4, the fifth switch K5 and the sixth switch K6 to be turned off, the positive output end of the auxiliary power supply 101 is grounded, and the negative output end of the auxiliary power supply 101 is used for raising the voltage to the ground of the bus capacitor 2021 through the fourth diode D4, the fifth diode D5 and the sixth diode D6, so as to charge the bus capacitor to a preset voltage, and then the inverter unit is started.

As another example, the control device 203, upon receiving the SVG power enable signal:

the controller controls the first switch K1 and the fifth switch K5 to be turned on, and controls the second switch K2, the third switch K3, the fourth switch K4 and the sixth switch K6 to be turned off, so that the positive output end of the auxiliary power supply 101 is electrically connected with the positive electrode of the bus capacitor 2021, the negative output end of the auxiliary power supply 101 is electrically connected with the negative electrode of the bus capacitor 2021, so as to charge the bus capacitor 2021, and the inverter unit is started after the bus capacitor is charged to a preset voltage.

Alternatively, two output terminal groups may be separately provided in the auxiliary power supply or the auxiliary device provided with the auxiliary power supply corresponding to the anti-PID power supply function and the SVG power supply function, and of course, the same output terminal group may be shared.

In one embodiment, the auxiliary power supply 101 has a first output terminal set and a second output terminal set, where the first output terminal set and the second output terminal set have the positive output terminal and the negative output terminal;

one of the positive electrode output end and the negative electrode output end of the first output end group is connected with the positive electrode and the negative electrode of the bus capacitor 2021, and the other is grounded;

The positive output end of the second output end group is electrically connected with the positive electrode of the busbar capacitor 2021, and the negative output end of the second output end group is electrically connected with the negative electrode of the busbar capacitor 2021;

the control device 203 is configured to control the first output terminal group to output a voltage when receiving an inverse PID power supply start signal; and when the SVG power starting signal is received, controlling the second output end group to output voltage.

The auxiliary power supply is provided with two voltage output branches, one branch is connected to the bus capacitor 2021 through the first output end group and grounded, and the other branch is connected to the positive end and the negative end of the bus capacitor 2021 through the second output end group, and specifically, the auxiliary power supply can be controlled and switched according to the received reverse PID power supply starting signal and SVG power supply starting signal, and the output voltage of the corresponding output end group is controlled.

Optionally, the first output terminal group and the second output terminal group are respectively arranged corresponding to the anti-PID power supply function and the SVG power supply function, so that circuit connection can be reduced.

The dc side of the inverter unit 201 is connected to the photovoltaic module 300, the photovoltaic module 300 includes at least one of a P-type panel and an N-type panel, and when the photovoltaic module 300 is a P-type panel:

in one embodiment, the control device 203 comprises a controller and a switching circuit 102, the switching circuit 102 comprising a first diode D1, a second diode D2 and a third diode D3,

The positive pole output of first output group respectively with the positive pole of first diode D1, the positive pole of second diode D2 is connected, the negative pole of first diode D1 with the positive pole of busbar capacitance 2021 is connected, the negative pole of second diode D2 with the positive pole of third diode D3 is connected, the negative pole of third diode D3 with the negative pole of busbar capacitance 2021 is connected, the negative pole output ground connection of first output group.

Alternatively, a current limiting component may be provided, where the current limiting component may use a current limiting resistor, and the negative output end of the first output end group is grounded through the current limiting resistor R2.

Further, the positive electrode output end of the second output end group is connected with the positive electrode of the bus capacitor through a resistor R1, and the negative electrode output end of the second output end group is connected with the negative electrode of the bus capacitor.

In one embodiment, the input of the auxiliary power supply 101 is powered from the ac side.

Optionally, the input end of the auxiliary power supply 101 is powered through the power grid 400.

Optionally, the photovoltaic inverter further comprises a sampling circuit 204.

The anti-PID sampling circuit comprises a BUS+ grounding sampling circuit, a BUS-grounding sampling circuit and an anti-PID power supply voltage sampling circuit, wherein the PV end is connected with a photovoltaic module, and information such as ISO impedance, PV+ grounding voltage, PV-grounding voltage and the like can be calculated according to the three sampling circuits, so that the voltage and output power of the output end of the anti-PID power supply are ensured to be within a preset threshold range, and the anti-PID daytime protection and night repair functions are realized.

Specifically, to be used for realizing the SVG power function, can correspond to set up the SVG sampling circuit, the SVG sampling circuit includes three sampling circuit of BUS+ to ground sampling circuit, BUS-to ground sampling circuit, power supply voltage sampling circuit, can calculate out BUS capacitance voltage, SVG power output voltage according to three sampling circuit, ensures that the voltage of SVG power output can rise to the preset voltage, because the SVG power does not have long-term power, specifically accessible sampling circuit acquires SVG power to start inverter SVG power function when output reaches preset instantaneous power.

It should be noted that, to simplify the structure and reduce the cost, the anti-PID sampling circuit and the SVG sampling circuit may use the same sampling circuit.

The utility model also provides an auxiliary power supply device 100, referring to fig. 2, the auxiliary power supply device 100 is applied to a photovoltaic inverter, the photovoltaic inverter comprises an inversion unit 201 and a direct current bus 202, the direct current bus 202 is connected with a direct current side of the inversion unit 201, a bus capacitor 2021 is connected to the direct current bus 202, and the bus capacitor 2021 is used for starting the inversion unit 201 when a preset voltage is reached; the auxiliary power supply device 100 comprises an auxiliary power supply 101 and a switch switching circuit 102, wherein the auxiliary power supply 101 is provided with a positive electrode output end and a negative electrode output end;

Upon receiving an inverse PID power start signal, the switch switching circuit 102 connects one of the positive output terminal and the negative output terminal of the auxiliary power supply 101 to the positive electrode and the negative electrode of the bus capacitor 2021, and the other is grounded, so that the bus capacitor 2021 is charged to a preset voltage for starting the inverter unit 201;

upon receiving the SVG power supply start signal, the switch switching circuit 102 electrically connects the positive output terminal of the auxiliary power supply 101 with the positive electrode of the bus capacitor 2021, and the negative output terminal of the auxiliary power supply 101 is electrically connected with the negative electrode of the bus capacitor 2021, so that the bus capacitor 2021 is charged to a preset voltage for starting the inverter unit 201.

In one embodiment, the dc side of the inverter unit 201 is connected to the photovoltaic module 300,

when the photovoltaic module 300 is a P-type battery board, the positive electrode output end of the auxiliary power supply 101 charges the positive electrode and the negative electrode of the bus capacitor 2021, and the negative electrode output end of the auxiliary power supply 101 is grounded;

when the photovoltaic module 300 is an N-type battery board, the negative output end of the auxiliary power supply 101 charges the positive electrode and the negative electrode of the bus capacitor 2021, and the positive output end of the auxiliary power supply 101 is grounded.

The embodiments of the auxiliary power device are basically the same as the embodiments of the photovoltaic inverter, and therefore will not be described in detail herein.

The present utility model further provides another auxiliary power supply device 100, referring to fig. 3, the auxiliary power supply device 100 is applied to a photovoltaic inverter, the photovoltaic inverter includes an inverter unit 201 and a dc bus 202, the dc bus 202 is connected to a dc side of the inverter unit 201, a bus capacitor 2021 is connected to the dc bus 202, and the bus capacitor 2021 is used to start the inverter unit 201 when a preset voltage is reached; the auxiliary power supply device 100 comprises an auxiliary power supply 101, wherein the auxiliary power supply 101 is provided with a first output end group and a second output end group, and the first output end group and the second output end group are respectively provided with an anode output end and a cathode output end;

one of the positive electrode output end and the negative electrode output end of the first output end group is used for connecting the positive electrode and the negative electrode of the bus capacitor 2021, and the other is grounded;

the positive output end of the second output end group is used for being electrically connected with the positive electrode of the busbar capacitor 2021, and the negative output end of the second output end group is used for being electrically connected with the negative electrode of the busbar capacitor 2021;

In one embodiment, the auxiliary power device 100 further includes a switch-switching circuit 102,

when receiving the reverse PID power supply starting signal, the switch switching circuit 102 turns on the first output end group and turns off the second output end group;

upon receiving the SVG power enable signal, the switch switching circuit 102 turns on the second output terminal group and turns off the first output terminal group.

when the photovoltaic module 300 is a P-type battery board, the positive electrode output end of the first output end group charges the positive electrode and the negative electrode of the busbar capacitor 2021, and the negative electrode output end of the first output end group is grounded;

when the photovoltaic module 300 is an N-type battery board, the negative output end of the second output end group charges the positive electrode and the negative electrode of the busbar capacitor 2021, and the positive output end of the second output end group is grounded.

It should be noted that the auxiliary power supply device shown in the present utility model may be mounted in a photovoltaic inverter; the device can also be matched with a connecting device associated with the photovoltaic inverter; or may be provided independently of the photovoltaic inverter.

The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims

1. A photovoltaic inverter, comprising:

an inversion unit;

an auxiliary power supply having a positive output and a negative output; and

2. The photovoltaic inverter of claim 1, wherein the control device comprises a controller and a switching circuit, the controller is configured to control the switching circuit to connect one of a positive output terminal and a negative output terminal of the auxiliary power supply to a positive electrode and a negative electrode of the bus capacitor when receiving an inverse PID power supply start signal, and the other is grounded, so that the auxiliary power supply starts the inverter unit after charging the bus capacitor to a preset voltage;

3. The photovoltaic inverter of claim 2, wherein the switch switching circuit comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch, the first switch, the sixth switch, and the third switch are sequentially connected in series, a first end of the first switch and a first end of the second switch are respectively connected to an anode output of the auxiliary power supply, a second end of the second switch is grounded, a first end of the third switch, a first end of the fourth switch, and a first end of the fifth switch are respectively connected to a cathode output of the auxiliary power supply, a second end of the fourth switch is grounded, a second end of the third switch, a second end of the fifth switch, and a second end of the sixth switch are respectively connected to a cathode of the bus capacitor, and a second end of the first switch and a second end of the third switch are respectively connected to an anode of the bus capacitor.

4. The photovoltaic inverter of claim 3, wherein the dc side of the inverter unit is connected to a photovoltaic module, and when the photovoltaic module is a P-type panel, the controller controls the first switch, the fourth switch, and the sixth switch to be turned on, and controls the second switch, the third switch, and the fifth switch to be turned off, so that the positive output terminal of the auxiliary power supply charges the positive and negative electrodes of the bus capacitor, and the negative output terminal of the auxiliary power supply is grounded.

5. The photovoltaic inverter of claim 3, wherein the dc side of the inverter unit is connected to a photovoltaic module, and when the photovoltaic module is an N-type panel, the controller controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch, the fifth switch and the sixth switch to be turned off, so that the negative output end of the auxiliary power supply charges the positive and negative electrodes of the bus capacitor, and the positive output end of the auxiliary power supply is grounded.

6. The photovoltaic inverter of claim 3, wherein the switching circuit further comprises a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode, the second end of the first switch is connected to the positive electrode of the bus capacitor via the first diode, the second end of the third switch is connected to the positive electrode of the bus capacitor via the fourth diode, the second diode and the third diode are connected between the second end of the first switch and the first end of the sixth switch, and the second end of the third switch is connected to the negative electrode of the bus capacitor via the sixth diode and the fifth diode.

7. The photovoltaic inverter of claim 1 wherein the auxiliary power source has a first set of outputs and a second set of outputs, each of the first and second sets of outputs having the positive and negative outputs;

8. The photovoltaic inverter of claim 7, wherein the control device comprises a controller and a switching circuit, the switching circuit comprises a first diode, a second diode, and a third diode, the positive output terminals of the first output terminal group are respectively connected with the anode of the first diode and the anode of the second diode, the cathode of the first diode is connected with the positive electrode of the bus capacitor, the cathode of the second diode is connected with the anode of the third diode, the cathode of the third diode is connected with the negative electrode of the bus capacitor, and the negative output terminals of the first output terminal group are grounded.

9. The photovoltaic inverter of any of claims 1-8 wherein the input of the auxiliary power source is powered from the ac side.

10. The auxiliary power supply device is characterized by being applied to a photovoltaic inverter, wherein the photovoltaic inverter comprises an inversion unit and a direct current bus, the direct current bus is connected with the direct current side of the inversion unit, a bus capacitor is connected to the direct current bus, and the bus capacitor is used for starting the inversion unit when a preset voltage is reached; the auxiliary power supply device comprises an auxiliary power supply and a switch switching circuit, wherein the auxiliary power supply is provided with a positive electrode output end and a negative electrode output end;

11. The auxiliary power unit according to claim 10, wherein the DC side of the inverter unit is connected to a photovoltaic module,

12. The auxiliary power supply device is characterized by being applied to a photovoltaic inverter, wherein the photovoltaic inverter comprises an inversion unit and a direct current bus, the direct current bus is connected with the direct current side of the inversion unit, a bus capacitor is connected to the direct current bus, and the bus capacitor is used for starting the inversion unit when a preset voltage is reached; the auxiliary power supply device comprises an auxiliary power supply, wherein the auxiliary power supply is provided with a first output end group and a second output end group, and the first output end group and the second output end group are respectively provided with an anode output end and a cathode output end;

13. The auxiliary power unit as claimed in claim 12, wherein the dc side of the inverter unit is connected to a photovoltaic module,