CN212323990U - Auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inversion system - Google Patents
Auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inversion system Download PDFInfo
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- CN212323990U CN212323990U CN202020611159.8U CN202020611159U CN212323990U CN 212323990 U CN212323990 U CN 212323990U CN 202020611159 U CN202020611159 U CN 202020611159U CN 212323990 U CN212323990 U CN 212323990U
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Abstract
The application provides auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inverter system, this auxiliary power supply's start protection circuit specifically includes: a power regulation circuit and a power control circuit; the power adjusting circuit is arranged between the positive and negative poles of the direct current bus of the inverter, and the positive and negative poles of the input end of the power control circuit are correspondingly connected with the positive and negative poles of the upper half bus capacitor or the lower half bus capacitor; the output end is connected with the control end of the auxiliary power supply and outputs a starting control signal; the upper limit value of the absorption power of the power adjusting circuit is a preset value, so that the voltage of the direct current bus can be absorbed when the power of the direct current bus is lower than the preset value, and the power control circuit generates and outputs a starting control signal when the voltage of a half bus capacitor connected with the power control circuit is higher than the preset voltage, so as to control the auxiliary power supply to start; that is, the scheme can reduce the occurrence of the phenomenon of open-circuit voltage virtual high on the direct-current bus and avoid frequent starting of the inverter auxiliary power supply.
Description
Technical Field
The utility model relates to an integrated circuit field, concretely relates to auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inverter system.
Background
The common power taking mode of an auxiliary power supply of an inverter in a photovoltaic inversion system can be divided into the following steps: the method comprises the following steps of taking power from a power grid, taking power from the power grid and a photovoltaic inverter direct current bus which are mutually ejected, and taking power from the photovoltaic inverter direct current bus. If the mode of taking power from a power grid or taking power from the mutual top of the power grid and an inverter direct current bus is adopted, the auxiliary power supply needs to complete ACDC conversion, a rectifier bridge and a large input capacitor are needed, and standby loss can be caused at night.
In the process of directly getting electricity from the inverter direct current bus, if the sunlight is weak due to weather, a higher open-circuit voltage is still applied to the inverter direct current bus according to the output characteristics of the solar cell panel, and the phenomenon of virtual high open-circuit voltage occurs. When the voltage on the direct current bus of the inverter reaches the starting voltage of the auxiliary power supply, the auxiliary voltage can start to work, the started auxiliary power supply needs to absorb current from the direct current bus, but the current output by the solar panel is limited at the moment, the voltage on the direct current bus is rapidly reduced along with the continuous increase of the current absorbed by the auxiliary power supply, the voltage on the direct current bus finally cannot meet the working requirement of the auxiliary power supply, and the auxiliary power supply is forced to be closed. When the auxiliary power supply is turned off, the voltage of the solar panel rises to a higher value, the voltage on the direct current bus meets the starting requirement of the auxiliary power supply again, and the auxiliary power supply is restarted … … for repeated circulation, so that the auxiliary power supply and the inverter are greatly damaged.
SUMMERY OF THE UTILITY MODEL
Based on the not enough of above-mentioned prior art, the utility model provides an auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inverter system to when solving current dc-to-ac converter direct current bus and appearing the virtual high phenomenon of open circuit voltage, the problem that leads to the frequent start-up of auxiliary power supply of dc-to-ac converter.
In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:
the application discloses in a first aspect a starting protection circuit of an auxiliary power supply, which is arranged between a positive electrode and a negative electrode of a direct current bus of an inverter, wherein a direct current bus capacitor of the inverter comprises an upper half bus capacitor and a lower half bus capacitor which are connected in series between the positive electrode and the negative electrode of the direct current bus; the start-up protection circuit of the auxiliary power supply includes: a power regulation circuit and a power control circuit;
the power adjusting circuit is connected between the positive electrode and the negative electrode of the direct current bus, and the upper limit value of the absorbed power of the power adjusting circuit is a preset value;
the positive and negative electrodes of the input end of the power supply control circuit are correspondingly connected with the positive and negative electrodes of the upper half bus capacitor or the lower half bus capacitor;
the output end of the power supply control circuit is connected with the control end of the auxiliary power supply and outputs a starting control signal; the starting control signal is generated when the voltage of a half bus capacitor connected with the power supply control circuit is greater than a preset voltage.
Optionally, in the start-up protection circuit of the auxiliary power supply, the preset value is a start-up power of the auxiliary power supply.
Optionally, in the start-up protection circuit of an auxiliary power supply, the power supply control circuit includes: the circuit comprises a first resistor, a second resistor and a first capacitor;
one end of the first resistor is used as the anode of the input end of the power supply control circuit;
the other end of the first resistor is respectively connected with one end of the second resistor and one end of the first capacitor;
the other end of the second resistor is connected with the other end of the first capacitor, and a connection point is used as the cathode of the input end of the power supply control circuit;
and the common end of the first resistor, the second resistor and the first capacitor is used as the output end of the power supply control circuit to output the starting control signal.
Optionally, in the start-up protection circuit of an auxiliary power supply, the power adjustment circuit includes: a power consumption circuit and a power consumption control circuit;
the power consumption circuit and the power consumption control circuit are connected between the positive electrode and the negative electrode of the direct current bus, and the output end of the power consumption control circuit is connected with the control end of the power consumption circuit;
the output end of the power consumption control circuit outputs a power consumption enable signal or a power consumption stop signal; the power consumption enabling signal is generated when the power on the direct current bus is smaller than the absorbed power upper limit value, and the power consumption stopping signal is generated when the power on the direct current bus is larger than or equal to the absorbed power upper limit value.
Optionally, in the start-up protection circuit of an auxiliary power supply, the power consumption circuit includes: a power consuming device and a first switching device;
one end of the power consumption device is connected with the anode of the direct current bus, and the other end of the power consumption device is connected with the first end of the first switching device;
a control end of the first switching device is used as a control end of the power consumption circuit, is connected with an output end of the power consumption control circuit, and receives the power consumption enabling signal or the power consumption stopping signal;
and the second end of the first switching device is connected with the negative electrode of the direct current bus.
Optionally, in the start-up protection circuit of the auxiliary power supply, the power consumption device is a resistor;
the first switching device is a switching tube;
the grid electrode of the switching tube is used as the control end of the first switching device;
the source electrode of the switching tube is used as the second end of the first switching device;
and the drain electrode of the switching tube is used as the first end of the first switching device.
Optionally, in the start-up protection circuit of an auxiliary power supply, the first switching device further includes: a first zener diode;
the cathode of the first voltage stabilizing diode is connected with the grid electrode of the switch tube, and the anode of the first voltage stabilizing diode is connected with the source electrode of the switch tube.
Optionally, in the start-up protection circuit of an auxiliary power supply, the power consumption control circuit includes: the third resistor, the fourth resistor, the fifth resistor, the sixth resistor and the switch tube;
one end of the third resistor and one end of the fourth resistor are both connected with the anode of the direct current bus;
the other end of the third resistor is connected with the grid electrode of the switching tube and one end of the fifth resistor respectively;
the source electrode of the switching tube and the other end of the fifth resistor are connected with the negative electrode of the direct current bus;
the other end of the fourth resistor is respectively connected with the drain electrode of the switching tube and one end of the sixth resistor, and a connection point is used as the output end of the power consumption control circuit;
the other end of the sixth resistor is connected with the negative electrode of the direct current bus.
Optionally, the resistance value of the third resistor is greater than a preset resistance value.
Optionally, in the start-up protection circuit of an auxiliary power supply, the power consumption control circuit further includes: a second zener diode;
and the cathode of the second voltage-stabilizing diode is connected with the grid electrode of the switching tube, and the anode of the second voltage-stabilizing diode is connected with the source electrode of the switching tube.
A second aspect of the present application discloses an inverter, comprising: an inverter unit, a controller, an auxiliary power supply and a start-up protection circuit for the auxiliary power supply as disclosed in any one of the above first aspects;
the inversion unit is controlled by the controller;
the power supply end of the controller is connected with the output end of the auxiliary power supply;
the input end of the auxiliary power supply is connected with the positive electrode of the direct current bus of the inversion unit;
and the control end of the auxiliary power supply is connected with the output end of the starting protection circuit of the auxiliary power supply.
Optionally, in the inverter described above, the inverter unit is a midpoint clamp inverter circuit.
Optionally, in the inverter described above, the auxiliary power supply includes: the auxiliary power supply control chip, the first diode, the transformer, the first switch and the rectification filter circuit;
the power supply end of the auxiliary power supply control chip is connected with the cathode of the first diode, and the connection point is used as the control end of the auxiliary power supply;
the anode of the first diode is connected with the homonymous end of a first secondary winding of the transformer, and the heteronymous end of the first secondary winding is grounded;
the communication end of the auxiliary power supply control chip is connected with the control end of the first switch;
the dotted terminal of the primary winding of the transformer is used as the input terminal of the auxiliary power supply and is connected with the positive electrode of the direct current bus;
the different name end of the primary winding is grounded through the first switch;
a second secondary winding of the transformer is connected with the input end of the rectification filter circuit, and the synonym end of the second secondary winding is grounded;
and the output end of the rectification filter circuit is used as the output end of the auxiliary power supply.
The third aspect of the present application discloses a photovoltaic inverter system, including: at least one photovoltaic array and at least one inverter as disclosed in any of the second aspects;
and the input end of the inverter is connected with the output side corresponding to the photovoltaic array.
Based on the start protection circuit of auxiliary power supply that this application embodiment provided above, specifically include: a power regulation circuit and a power control circuit; the power adjusting circuit is arranged between the positive and negative poles of the direct current bus of the inverter, and the positive and negative poles of the input end of the power control circuit are correspondingly connected with the positive and negative poles of the upper half bus capacitor or the lower half bus capacitor; the output end of the power supply control circuit is connected with the control end of the auxiliary power supply and outputs a starting control signal; the upper limit value of the absorption power of the power adjusting circuit is a preset value, so that the voltage of the direct current bus can be absorbed when the power of the direct current bus is lower than the preset value; when the voltage of the half-bus capacitor connected with the power supply control circuit is greater than the preset voltage, the power supply control circuit generates and outputs a starting control signal to control the auxiliary power supply to start; that is, the start protection circuit of the auxiliary power supply provided by the application realizes the start control of the auxiliary power supply by adopting a mode that the power adjusting circuit and the power control circuit are matched with each other; therefore, the phenomenon of the virtual high of the open-circuit voltage of the direct-current bus can be reduced, and the inverter auxiliary power supply is prevented from being started frequently.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a start protection circuit of an auxiliary power supply according to an embodiment of the present disclosure;
fig. 2 to fig. 3 are schematic structural diagrams of start-up protection circuits of two other auxiliary power supplies according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a specific start protection circuit of an auxiliary power supply according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of another inverter according to another embodiment of the present application;
fig. 6 is a schematic structural diagram of a photovoltaic inverter system according to another embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The embodiment of the application provides a starting protection circuit of an auxiliary power supply, which aims to solve the problem that the auxiliary power supply of an inverter is frequently started when an open-circuit voltage virtual high phenomenon occurs in a direct-current bus of the existing inverter.
Referring to fig. 1, the start protection circuit of the auxiliary power supply is disposed between the positive and negative poles (BUS +, BUS-) of the dc BUS of the inverter, and the dc BUS capacitor of the inverter includes an upper half BUS capacitor and a lower half BUS capacitor connected in series between the positive and negative poles of the dc BUS. Specifically, the start protection device of the auxiliary power supply mainly comprises: a power regulation circuit 101 and a power supply control circuit 102.
The power adjusting circuit 101 is connected between the positive electrode and the negative electrode of the direct current bus, and the upper limit value of the absorbed power of the power adjusting circuit 101 is a preset value.
In practical applications, the power adjusting circuit 101 is mainly used for adjusting the power on the dc bus. Specifically, when the upper limit value of the absorbed power does not reach a preset value, the power adjusting circuit 101 absorbs the power on the dc bus; and stopping absorbing the power on the direct current bus after the upper limit value of the absorbed power reaches a preset value.
Specifically, the preset value may be the starting power of the auxiliary power supply. Of course, the preset value is not limited to this, and may be a certain value in a range around the starting power of the auxiliary power supply. In practical application, the preset value does not need to be the starting power of the auxiliary power supply, and only needs to ensure that the power on the direct current bus is close to the requirement of the auxiliary power supply.
It should be noted that the specific value of the preset value can be determined by itself according to the application environment and the user requirement, and the specific value of the preset value is within the protection scope of the present application.
The positive and negative poles of the input end of the power control circuit 102 are correspondingly connected with the positive and negative poles of the upper half bus capacitor or the lower half bus capacitor, and fig. 1-4 show the case that the positive and negative poles of the input end of the power control circuit 102 are correspondingly connected with the positive and negative poles of the lower half bus capacitor, that is, the positive pole of the input end of the power control circuit 102 is connected with the connection point of the upper half bus capacitor and the lower half bus capacitor, and the negative pole of the input end of the power control circuit 102 is connected with the negative pole; in practical applications, the positive and negative electrodes of the input end of the power control circuit 102 may also be connected to the positive and negative electrodes of the upper half bus capacitor, which is not shown in the drawings, and is also within the protection scope of the present application.
The output terminal of the power control circuit 102 is connected to the control terminal of the auxiliary power supply, and outputs a start control signal.
The start control signal is generated when the voltage on the half-bus capacitor connected to the power control circuit 102 is greater than a preset voltage.
The specific value of the preset voltage may be a voltage on a half-bus capacitor (for example, the lower half-bus capacitor shown in fig. 1 to 4) corresponding to the starting power of the auxiliary power supply, or may also be a voltage value on a half-bus capacitor (for example, the lower half-bus capacitor shown in fig. 1 to 4) that needs to be met when the auxiliary power supply is started.
In practical application, after the power adjustment circuit 101 stops absorbing the power on the bus, the power on the dc bus enters the upper half bus capacitor and the lower half bus capacitor connected in series between the positive electrode and the negative electrode of the dc bus, at this time, the upper half bus capacitor and the lower half bus capacitor perform a charging operation, the voltages on the upper half bus capacitor and the lower half bus capacitor continuously increase, and when the voltage on the half bus capacitor (for example, the lower half bus capacitor shown in fig. 1 to 4) connected to the power control circuit 102 is greater than a preset voltage, the power control circuit 102 outputs a start control signal to control the auxiliary power to start.
Based on the principle, the power adjusting circuit 101 and the power control circuit 102 are matched with each other in the embodiment to realize the starting control of the auxiliary power supply, and because the upper limit value of the absorption power of the power adjusting circuit 101 is a preset value, the voltage of the direct current bus can be absorbed when the power of the direct current bus is lower than the preset value; when the voltage on the half-bus capacitor (such as the lower half-bus capacitor shown in fig. 1-4) connected to the power control circuit 102 is greater than the preset voltage, the power control circuit generates and outputs a start control signal to control the auxiliary power supply to start; that is, the start protection circuit of the auxiliary power supply provided by the application realizes the start control of the auxiliary power supply by adopting a mode that the power adjusting circuit and the power control circuit are matched with each other; therefore, the phenomenon of the virtual high of the open-circuit voltage of the direct-current bus can be reduced, and the inverter auxiliary power supply is prevented from being started frequently.
It is worth to be noted that, in the prior art, the power control circuit provided for the auxiliary power supply is generally directly provided between the positive electrode and the negative electrode of the dc bus, and this connection manner causes many devices on the power control circuit to bear relatively large stress, so that a high-voltage-resistant device needs to be selected, which undoubtedly increases the cost of starting the protection circuit; in the start protection circuit of the auxiliary power supply provided by the application, the positive and negative electrodes of the input end of the power supply control circuit 102 are correspondingly connected with the positive and negative electrodes of the upper half bus capacitor or the lower half bus capacitor, that is, the power supply control circuit 102 is only connected in parallel with the half bus capacitors, and only half of the direct current bus voltage needs to be borne in the use process, so that the bearing stress of devices in the power supply control circuit 102 can be reduced, and the cost of starting the protection circuit can also be reduced.
Optionally, in another embodiment provided in the present application, please refer to fig. 2, the power adjustment circuit 101 includes: a power consumption circuit 1011 and a power consumption control circuit 1012.
The power consumption circuit 1011 and the power consumption control circuit 1012 are both connected between the positive and negative poles of the dc bus, and the output terminal of the power consumption control circuit 1012 is connected to the control terminal of the power consumption circuit 1011.
An output terminal of the power consumption control circuit 1012 outputs a power consumption enable signal or a power consumption stop signal. The power consumption enabling signal is generated when the power on the direct current bus is smaller than the upper limit value of the absorbed power, and the power consumption stopping signal is generated when the power on the direct current bus is larger than or equal to the upper limit value of the absorbed power.
In practical application, the power consumption control circuit 1012 generates a power consumption enable signal when the power on the dc bus is smaller than the upper limit of the absorbed power according to the change of the power on the dc bus, and controls the power consumption circuit 1011 to perform an unloading operation, so as to reduce the occurrence of an open-circuit voltage virtual high phenomenon on the dc bus; when the power on the dc bus is equal to or higher than the absorbed power upper limit value, a power consumption stop signal is generated to control the power consumption circuit 1011 to stop the unloading operation in preparation for starting the auxiliary power supply.
Specifically, referring to fig. 3, in practical applications, the power consumption circuit 1011 mainly includes a power consumption device 1013 and a first switching device 1014.
One end of power consumption device 1013 is connected to dc BUS positive BUS +, and the other end is connected to a first end of first switching device 1013.
The control terminal of the first switch device 1014 is connected to the output terminal of the power consumption control circuit 1012 as the control terminal of the power consumption circuit 1011, and receives the power consumption enable signal or the power consumption stop signal, and the second terminal of the first switch device 1014 is connected to the dc BUS negative BUS-.
In practical application, referring to fig. 4, the power dissipation device is a resistor R0. One end of the resistor R0 is connected to the positive electrode of the dc bus, and is used to consume power on the dc bus when the circuit between the power consumption device and the first switching device is on.
The first switching device includes: a switching tube Q1 and a first zener diode Z1.
The gate of the switching tube Q1 serves as the control terminal of the first switching device.
The source of the switching tube Q1 serves as the second terminal of the first switching device.
The drain of the switching tube Q1 serves as the first terminal of the first switching device.
In practical applications, the specific type of the switching tube Q1 may be an NMOS transistor, or may be another type of switching tube, and the specific type of the switching tube Q1 is not limited in this application, and all of them belong to the protection scope of this application.
In practical applications, the first switching device further includes: a first zener diode Z1.
The cathode of the first zener diode Z1 is connected to the gate of the switch Q1, and the anode of the first zener diode Z1 is connected to the source of the switch Q1.
It should be noted that the gate of the switching tube Q1 can be protected from overvoltage damage by adjusting the regulated voltage value of the first zener diode Z1.
Optionally, referring also to fig. 4, in another embodiment provided by the present application, the power consumption control circuit 1012 mainly includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a switch tube Q2.
One end of the third resistor R3 and one end of the fourth resistor R4 are both connected with the positive electrode BUS + of the direct current BUS, the other end of the third resistor R3 is respectively connected with the grid of the switch tube Q2 and one end of the fifth resistor R5, and the source of the switch tube Q2 and the other end of the fifth resistor R5 are both connected with the negative electrode BUS-of the direct current BUS.
The other end of the fourth resistor R4 is connected to the drain of the switch Q2 and one end of the sixth resistor R6, respectively, and the connection point is used as the output terminal of the power consumption control circuit 1012.
The other end of the sixth resistor R6 is connected to the negative BUS-of the dc BUS.
The common terminal of the fourth resistor R4, the switch Q2 and the sixth resistor R6 is used as the output terminal of the power consumption control circuit 1012.
In practical applications, the specific type of the switching tube Q2 may be an NMOS transistor, or may be another type of switching tube, and the specific type of the switching tube Q2 is not limited in this application, and all of them belong to the protection scope of this application.
In practical application, when the voltage on the dc bus reaches a certain voltage, that is, when the power on the dc bus is smaller than the upper limit value of absorbed power, the fourth resistor R4 and the sixth resistor R6 divide the voltage and output a power consumption enable signal, so as to control the switching tube Q1 in the power consumption circuit 102 to be in an unloading working state; with the gradual rise of the voltage on the dc bus, when the power on the dc bus is greater than or equal to the absorbed power upper limit value, the voltage division of the third resistor R3 and the fifth resistor R5 makes the gate voltage of the switching tube Q2 reach its turn-on threshold, the drain and the source of the switching tube Q2 are turned on, the gate voltage of the switching tube Q1 is pulled down, and at this time, the power consumption device R0 in the power consumption circuit 102 stops the consumption operation.
It should be noted that, in practical applications, the third resistor R3 may be set to be a resistor with a large resistance value, so that the third resistor R3 hardly consumes the charge on the dc bus, and unnecessary power consumption can be avoided.
Preferably, also referring to fig. 4, in practical applications, the control circuit further comprises: and a second zener diode Z2.
The cathode Z2 of the second zener diode is connected to the gate of the switch Q2, and the anode of the second zener diode Z2 is connected to the source of the switch Q2.
It should be noted that the gate of the switching tube Q2 can be protected from overvoltage damage by adjusting the regulated voltage value of the second zener diode Z2.
Optionally, in another embodiment provided in the present application, please refer to fig. 4, the power control circuit mainly includes: a first resistor R1, a second resistor R2 and a first capacitor C3.
One end of the first resistor R1, which is the positive terminal of the input terminal of the power control circuit 102, is connected to the positive terminal of the upper half bus capacitor C1 (not shown), or to the connection point between the negative terminal of the upper half bus capacitor C1 and the positive terminal of the lower half bus capacitor C2 (shown in fig. 4).
The other end of the first resistor R1 is connected to one end of the second resistor R2 and one end of the first capacitor C3, respectively.
The other end of the second resistor R2 is connected to the other end of the first capacitor, and the connection point is the negative terminal of the input terminal of the power control circuit 102, and is connected to the connection point between the negative terminal of the upper half BUS capacitor C1 and the positive terminal of the lower half BUS capacitor C2 (not shown), or is connected to the negative terminal BUS-of the dc BUS (as shown in fig. 4).
The common terminal of the first resistor R1, the second resistor R2 and the first capacitor C3 serves as the output terminal of the power control circuit 102, and outputs a start control signal.
Based on the above, with reference to fig. 4, a detailed description is given to a specific operation process of the start protection circuit of the auxiliary power supply:
(1) when the power on the dc bus is smaller than the absorbed power upper limit value, the fourth resistor R4 and the sixth resistor R6 in the power consumption control circuit 1012 divide the voltage on the dc bus to generate a power consumption enable signal, so as to control the switching transistor Q1 in the power consumption circuit 1011 to be turned on, and the resistor R0 in the power consumption circuit 1011 absorbs the power on the dc bus.
(2) When the power on the dc bus is greater than or equal to the absorbed power upper limit value, the voltage on the dc bus is divided by the third resistor R3 and the fifth resistor R5 in the power consumption control circuit 1012, the switching tube Q2 generates a power consumption stop signal, and the gate voltage of the switching tube Q1 in the power consumption circuit 1011 is pulled down, so that the switching tube Q1 is in an off state, and at this time, the resistor R0 no longer absorbs the power on the dc bus, that is, the stop unloading operation in the power consumption circuit 1011 is controlled. Then an upper half direct current bus capacitor C1 and a lower half direct current bus capacitor C2 on the direct current bus are charged, and the lower half direct current bus capacitor C2 charges a first capacitor C3; through setting up the resistance of first resistance R1 and second resistance R2, can make the voltage on the lower half bus capacitor C2 of direct current bus reach and predetermine the voltage, correspond first electric capacity C3 and charge to the required voltage of control chip start-up in the auxiliary power supply 103, and then realize starting the control chip in the auxiliary power supply 103.
The specific working process when the positive and negative electrodes of the input end of the power control circuit 102 are correspondingly connected with the positive and negative electrodes of the upper half bus capacitor C1 is similar to that described above, and details are not repeated here.
Based on the start protection circuit of the auxiliary power supply provided in the above embodiment, another embodiment of the present application further provides an inverter, please refer to fig. 5, where the inverter mainly includes: the inverter unit 601, the controller 602, the auxiliary power supply 603, and the start-up protection circuit 604 of the auxiliary power supply according to any of the embodiments described above.
The inverter unit 601 is controlled by the controller 602.
A power supply terminal of the controller 602 is connected to an output terminal of the auxiliary power supply 603.
In practical applications, the working power of the controller 602 is provided by the auxiliary power source 603, and the auxiliary power source 603 outputs power to power the controller 602 after being started, so that the controller 602 performs subsequent control operations.
The input end of the auxiliary power 603 is connected to the positive electrode (BUS + in fig. 5) of the dc BUS of the inverter unit 601, that is, the auxiliary power 603 takes power from the dc BUS of the inverter.
The control terminal of the auxiliary power supply 603 is connected to the output terminal of the start-up protection circuit 604 of the auxiliary power supply.
In practical applications, whether the auxiliary power 603 is started or not is controlled by a start control signal output from an output terminal of a start protection circuit 604 of the auxiliary power.
It should be noted that, for a related description of the start protection circuit 604 of the auxiliary power supply, reference may be made to the embodiments corresponding to fig. 1 to fig. 4, and details are not repeated herein.
In this embodiment, the start protection circuit 604 of the auxiliary power supply in the inverter realizes the start control of the auxiliary power supply 603 by adopting a way that the power adjustment circuit and the power control circuit are matched with each other, because the upper limit value of the absorption power of the power adjustment circuit is a preset value, when the power of the direct current bus is lower than the preset value, the voltage of the direct current bus can be absorbed, and when the voltage on a half bus capacitor connected with the power control circuit in the start protection circuit 604 is greater than the preset voltage, the power control circuit generates and outputs a start control signal to control the start operation of the auxiliary power supply; that is, the starting protection circuit of the auxiliary power supply realizes the starting control of the auxiliary power supply by adopting a mode that a power adjusting circuit and a power control circuit are matched with each other; the phenomenon of the open-circuit voltage virtual high of the direct-current bus can be further reduced, the inverter auxiliary power supply 603 can be prevented from being started frequently, and frequent hiccups of the auxiliary power supply 603 can be prevented; further, the damage to the inverter caused by frequent starting can be avoided.
Preferably, if the inverter unit 601 in the inverter is a midpoint clamp type inverter circuit, the power control circuit in the start protection circuit 604 of the auxiliary power supply only needs to be arranged between the positive and negative electrodes of the half-bus capacitor, for example, in the arrangement manner shown in fig. 1, 3, 4, and 5, that is, the power control circuit in the start protection circuit 604 of the auxiliary power supply in the inverter only needs to bear half of the dc bus voltage in the use process, so that the bearing stress of the device in the power control circuit can be reduced, and the manufacturing cost of the inverter is further reduced.
Referring also to fig. 4, in practical applications, the auxiliary power supply 103 includes: an auxiliary power supply control chip 1031, a first diode Z0, a transformer T1, a first switch K1 and a rectifier and filter circuit 1032.
The power supply terminal of the auxiliary power supply control chip 1031 is connected to the cathode of the first diode Z0, and the connection point serves as the control terminal of the auxiliary power supply 103.
The anode of the first diode Z0 is connected to the dotted terminal of the first secondary winding L1 of the transformer T1, and the dotted terminal of the first secondary winding L1 of the transformer T1 is grounded.
The communication terminal of the auxiliary power control chip 1031 is connected to the control terminal of the first switch K1.
The dotted terminal of the primary winding L1 of the transformer T1 is used as the positive terminal of the input terminal of the auxiliary power supply 103 and is connected to the positive terminal of the dc bus, and the dotted terminal of the primary winding L1 of the transformer T1 is grounded through the first switch K1.
The second secondary winding of the transformer T1 is connected to the input terminal of the rectifying and smoothing circuit 1032, and the synonym terminal of the second secondary winding is grounded.
The output terminal of the rectifying-filtering circuit 1032 serves as the output terminal of the auxiliary power supply 103.
In practical applications, the auxiliary power supply 103 may have other structures, and the present application is not limited to this embodiment, and all of the embodiments belong to the scope of the present application.
Based on the inverter provided in the foregoing embodiment, another embodiment of the present application further provides a photovoltaic inverter system, please refer to fig. 6, where the photovoltaic inverter system mainly includes: at least one photovoltaic array 701 and at least one inverter 702 as described in any of the above embodiments.
Wherein, the input end of the inverter 702 is connected with the output side of the corresponding photovoltaic array 701.
In practical applications, the photovoltaic array 701 is a power generation unit in a photovoltaic inverter system, and is used for converting solar energy into electric energy. The photovoltaic grid-connected inverter is mainly formed by connecting a plurality of photovoltaic modules, and electric energy is transmitted to the direct current side of the inverter 702 through the output end of a photovoltaic array.
It should be noted that, for a related description of the inverter 702, reference may be made to the embodiment corresponding to fig. 5, and details are not described here.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (14)
1. A starting protection circuit of an auxiliary power supply is characterized in that the starting protection circuit is arranged between a positive pole and a negative pole of a direct current bus of an inverter, and a direct current bus capacitor of the inverter comprises an upper half bus capacitor and a lower half bus capacitor which are connected in series between the positive pole and the negative pole of the direct current bus; the start-up protection circuit of the auxiliary power supply includes: a power regulation circuit and a power control circuit;
the power adjusting circuit is connected between the positive electrode and the negative electrode of the direct current bus, and the upper limit value of the absorbed power of the power adjusting circuit is a preset value;
the positive and negative electrodes of the input end of the power supply control circuit are correspondingly connected with the positive and negative electrodes of the upper half bus capacitor or the lower half bus capacitor;
the output end of the power supply control circuit is connected with the control end of the auxiliary power supply and outputs a starting control signal; the starting control signal is generated when the voltage of a half bus capacitor connected with the power supply control circuit is greater than a preset voltage.
2. The start-up protection circuit of an auxiliary power supply of claim 1, wherein the preset value is a start-up power of the auxiliary power supply.
3. The start-up protection circuit for an auxiliary power supply of claim 1, wherein the power supply control circuit comprises: the circuit comprises a first resistor, a second resistor and a first capacitor;
one end of the first resistor is used as the anode of the input end of the power supply control circuit;
the other end of the first resistor is respectively connected with one end of the second resistor and one end of the first capacitor;
the other end of the second resistor is connected with the other end of the first capacitor, and a connection point is used as the cathode of the input end of the power supply control circuit;
and the common end of the first resistor, the second resistor and the first capacitor is used as the output end of the power supply control circuit to output the starting control signal.
4. A start-up protection circuit for an auxiliary power supply as claimed in any one of claims 1 to 3, wherein said power regulation circuit comprises: a power consumption circuit and a power consumption control circuit;
the power consumption circuit and the power consumption control circuit are connected between the positive electrode and the negative electrode of the direct current bus, and the output end of the power consumption control circuit is connected with the control end of the power consumption circuit;
the output end of the power consumption control circuit outputs a power consumption enable signal or a power consumption stop signal; the power consumption enabling signal is generated when the power on the direct current bus is smaller than the absorbed power upper limit value, and the power consumption stopping signal is generated when the power on the direct current bus is larger than or equal to the absorbed power upper limit value.
5. The start-up protection circuit of an auxiliary power supply of claim 4, wherein the power dissipation circuit comprises: a power consuming device and a first switching device;
one end of the power consumption device is connected with the anode of the direct current bus, and the other end of the power consumption device is connected with the first end of the first switching device;
a control end of the first switching device is used as a control end of the power consumption circuit, is connected with an output end of the power consumption control circuit, and receives the power consumption enabling signal or the power consumption stopping signal;
and the second end of the first switching device is connected with the negative electrode of the direct current bus.
6. The start-up protection circuit of an auxiliary power supply according to claim 5, wherein the power consuming device is a resistor;
the first switching device is a switching tube;
the grid electrode of the switching tube is used as the control end of the first switching device;
the source electrode of the switching tube is used as the second end of the first switching device;
and the drain electrode of the switching tube is used as the first end of the first switching device.
7. The start-up protection circuit of an auxiliary power supply of claim 6, wherein said first switching device further comprises: a first zener diode;
the cathode of the first voltage stabilizing diode is connected with the grid electrode of the switch tube, and the anode of the first voltage stabilizing diode is connected with the source electrode of the switch tube.
8. The start-up protection circuit of an auxiliary power supply of claim 4, wherein the power consumption control circuit comprises: the third resistor, the fourth resistor, the fifth resistor, the sixth resistor and the switch tube;
one end of the third resistor and one end of the fourth resistor are both connected with the anode of the direct current bus;
the other end of the third resistor is connected with the grid electrode of the switching tube and one end of the fifth resistor respectively;
the source electrode of the switching tube and the other end of the fifth resistor are connected with the negative electrode of the direct current bus;
the other end of the fourth resistor is respectively connected with the drain electrode of the switching tube and one end of the sixth resistor, and a connection point is used as the output end of the power consumption control circuit;
the other end of the sixth resistor is connected with the negative electrode of the direct current bus.
9. The start-up protection circuit of an auxiliary power supply according to claim 8, wherein the third resistor has a resistance value larger than a predetermined resistance value.
10. The start-up protection circuit of an auxiliary power supply of claim 8, wherein the power consumption control circuit further comprises: a second zener diode;
and the cathode of the second voltage-stabilizing diode is connected with the grid electrode of the switching tube, and the anode of the second voltage-stabilizing diode is connected with the source electrode of the switching tube.
11. An inverter, comprising: a start-up protection circuit for an inverter unit, a controller, an auxiliary power supply and an auxiliary power supply according to any one of claims 1 to 10;
the inversion unit is controlled by the controller;
the power supply end of the controller is connected with the output end of the auxiliary power supply;
the input end of the auxiliary power supply is connected with the positive electrode of the direct current bus of the inversion unit;
and the control end of the auxiliary power supply is connected with the output end of the starting protection circuit of the auxiliary power supply.
12. The inverter according to claim 11, wherein the inverter unit is a midpoint clamp inverter circuit.
13. The inverter of claim 11, wherein the auxiliary power source comprises: the auxiliary power supply control chip, the first diode, the transformer, the first switch and the rectification filter circuit;
the power supply end of the auxiliary power supply control chip is connected with the cathode of the first diode, and the connection point is used as the control end of the auxiliary power supply;
the anode of the first diode is connected with the homonymous end of a first secondary winding of the transformer, and the heteronymous end of the first secondary winding is grounded;
the communication end of the auxiliary power supply control chip is connected with the control end of the first switch;
the dotted terminal of the primary winding of the transformer is used as the input terminal of the auxiliary power supply and is connected with the positive electrode of the direct current bus;
the different name end of the primary winding is grounded through the first switch;
a second secondary winding of the transformer is connected with the input end of the rectification filter circuit, and the synonym end of the second secondary winding is grounded;
and the output end of the rectification filter circuit is used as the output end of the auxiliary power supply.
14. A photovoltaic inverter system, comprising: at least one photovoltaic array and at least one inverter according to any one of claims 11-13;
and the input end of the inverter is connected with the output side corresponding to the photovoltaic array.
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| CN202020611159.8U CN212323990U (en) | 2020-04-22 | 2020-04-22 | Auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inversion system |
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| CN202020611159.8U CN212323990U (en) | 2020-04-22 | 2020-04-22 | Auxiliary power supply's start protection circuit, dc-to-ac converter and photovoltaic inversion system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113972817A (en) * | 2021-09-22 | 2022-01-25 | 华为数字能源技术有限公司 | Solid-state transformer fault handling system |
| CN116154740A (en) * | 2023-04-14 | 2023-05-23 | 江苏旭迈思能源科技有限公司 | Overvoltage protection circuit, method and system for input capacitor of miniature photovoltaic inverter |
| CN117394741A (en) * | 2023-12-12 | 2024-01-12 | 珠海格力电器股份有限公司 | Motor driving circuit, motor driving method, fan and unit |
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2020
- 2020-04-22 CN CN202020611159.8U patent/CN212323990U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113972817A (en) * | 2021-09-22 | 2022-01-25 | 华为数字能源技术有限公司 | Solid-state transformer fault handling system |
| CN116154740A (en) * | 2023-04-14 | 2023-05-23 | 江苏旭迈思能源科技有限公司 | Overvoltage protection circuit, method and system for input capacitor of miniature photovoltaic inverter |
| CN117394741A (en) * | 2023-12-12 | 2024-01-12 | 珠海格力电器股份有限公司 | Motor driving circuit, motor driving method, fan and unit |
| CN117394741B (en) * | 2023-12-12 | 2024-04-05 | 珠海格力电器股份有限公司 | Motor driving circuit, motor driving method, fan and unit |
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