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CN-224218281-U - Starting auxiliary source circuit, power supply circuit and photovoltaic inverter of photovoltaic inverter

CN224218281UCN 224218281 UCN224218281 UCN 224218281UCN-224218281-U

Abstract

The utility model provides a starting auxiliary source circuit of a photovoltaic inverter, a power supply circuit and the photovoltaic inverter. The starting auxiliary source circuit of the photovoltaic inverter comprises a half-wave rectifying unit, a full-wave rectifying unit and a first unidirectional conduction unit, wherein an alternating current input end of the full-wave rectifying unit is connected with an alternating current source of the starting auxiliary source circuit through the half-wave rectifying unit, a direct current output end of the full-wave rectifying unit is connected with a direct current bus of the photovoltaic inverter through the first unidirectional conduction unit, and a direct current output end of the full-wave rectifying unit outputs a first power supply voltage to the direct current bus and uses the voltage of the direct current bus as the starting voltage of the photovoltaic inverter.

Inventors

  • JI DEHAI
  • CHEN XUDONG
  • ZHANG XINGDONG
  • WU LIHUI

Assignees

  • 宁波德业变频技术有限公司

Dates

Publication Date
20260508
Application Date
20260408

Claims (12)

  1. 1. The starting auxiliary source circuit of the photovoltaic inverter is characterized by comprising a half-wave rectifying unit (12), a full-wave rectifying unit (11) and a first unidirectional conduction unit (17); the alternating current input end of the full-wave rectifying unit (11) is connected with an alternating current source (13) of the starting auxiliary source circuit through the half-wave rectifying unit (12), the direct current output end of the full-wave rectifying unit (11) is connected with a direct current bus (14) of the photovoltaic inverter through the first unidirectional conduction unit (17), and the direct current output end of the full-wave rectifying unit (11) outputs a first power supply voltage to the direct current bus (14) and uses the voltage of the direct current bus (14) as the starting voltage of the photovoltaic inverter.
  2. 2. The starting auxiliary source circuit of the photovoltaic inverter according to claim 1, further comprising a switching unit (15), wherein the direct current output end of the full wave rectifying unit (11) comprises a first direct current output end and a second direct current output end; The full-wave rectifying device comprises a full-wave rectifying unit (11), a first direct current output end, a first unidirectional conduction unit (17), a second end, a positive bus and a fourth end, wherein the first direct current output end of the full-wave rectifying unit (11) is connected with the first end of a switch unit (15), the second end of the switch unit (15) is connected with the positive bus of a direct current bus (14), the third end of the switch unit (15) is connected with the second direct current output end of the full-wave rectifying unit (11), and the fourth end of the switch unit (15) is connected with the negative bus of the direct current bus (14).
  3. 3. The starting auxiliary circuit of a photovoltaic inverter according to claim 2, characterized in that the switching unit (15) comprises a multi-pole relay (18) and a relay control module (19); The multi-knife relay (18) comprises a driving piece (183), a first switching piece (184) and a second switching piece (185); a first end of the first switch piece (184) is connected with a first end of the switch unit (15), and a second end of the first switch piece (184) is connected with a second end of the switch unit (15); A first end of the second switch piece (185) is connected with a third end of the switch unit (15), and a second end of the second switch piece (185) is connected with a fourth end of the switch unit (15); The relay control module (19) is connected with the first end of the driving piece (183), the second end of the driving piece (183) is connected with a third power supply voltage, and the relay control module (19) is used for controlling the on or off of the first switch piece (184) and the second switch piece (185).
  4. 4. A starting auxiliary circuit of a photovoltaic inverter according to claim 3, characterized in that the relay control module (19) comprises: -at least one fourth diode (D4), the anode of the fourth diode (D4) being connected to the first end of the driving member (183), the cathode of the fourth diode (D4) being connected to the second end of the driving member (183); a first resistor (R1), wherein a first end of the first resistor (R1) receives a relay control signal; A second resistor (R2), wherein a first end of the second resistor (R2) is connected with a first end of the first resistor (R1), and a second end of the second resistor (R2) is connected with the negative bus; the control electrode of the first switch tube (Q1) is connected with the second end of the first resistor (R1), the first electrode of the first switch tube (Q1) is connected with the first end of the driving piece (183), the second electrode of the first switch tube (Q1) is connected with the negative bus, and the control electrode of the first switch tube (Q1) controls the first electrode of the first switch tube (Q1) to be conducted or disconnected with the second electrode of the first switch tube (Q1) according to the relay control signal.
  5. 5. The starting auxiliary circuit of a photovoltaic inverter according to claim 4, characterized in that the number of the multi-knife relays (18) is two, defined as a first multi-knife relay (181) and a second multi-knife relay (182), respectively; the first switch piece (184) of the first multi-knife relay (181) is connected with the first end of the switch unit (15), one end of the first switch piece (184) of the second multi-knife relay (182) is connected with the first switch piece (184) of the first multi-knife relay (181), and the other end of the first switch piece (184) of the second multi-knife relay (182) is connected with the second end of the switch unit (15); A second switching element (185) of the first multi-knife relay (181) is connected with a third end of the switching unit (15), one end of the second switching element (185) of the second multi-knife relay (182) is connected with the second switching element (185) of the first multi-knife relay (181), and the other end of the second switching element (185) of the second multi-knife relay (182) is connected with a fourth end of the switching unit (15); The driving element (183) of the first multi-pole relay (181) and the driving element (183) of the second multi-pole relay (182) are both connected to the first pole of the first switching tube (Q1).
  6. 6. The starting auxiliary circuit of a photovoltaic inverter according to claim 5, further comprising a surge protection unit (16); The first direct current output end of the full-wave rectifying unit (11) is connected with the positive bus of the direct current bus (14) through the first unidirectional conduction unit (17), the second direct current output end of the full-wave rectifying unit (11) is connected with the negative bus of the direct current bus (14), the first end of the surge protection unit (16) is connected with the first direct current output end of the full-wave rectifying unit (11), and the second end of the surge protection unit (16) is connected with the second direct current output end of the full-wave rectifying unit (11); The surge protection unit (16) comprises a third resistor (R3), a fourth resistor (R4), a first capacitor (C1) and a second capacitor (C2); The first end of the third resistor (R3) is connected with the first direct current output end of the full-wave rectifying unit (11), the second end of the third resistor (R3) is connected with the first end of the fourth resistor (R4), and the second end of the fourth resistor (R4) is connected with the second direct current output end of the full-wave rectifying unit (11); a first end of the first capacitor (C1) is connected with a first direct current output end of the full-wave rectifying unit (11), a second end of the first capacitor (C1) is connected with a first end of the second capacitor (C2) and a second end of the first resistor (R1), and a second end of the second capacitor (C2) is connected with the second direct current output end; The first direct current output end of the full-wave rectifying unit (11) is connected with the first switch piece (184) through the first unidirectional conduction unit (17), the first unidirectional conduction unit (17) is a fourth diode (D4), the anode of the fourth diode (D4) is connected with the first end of the first switch piece (184), the cathode of the fourth diode (D4) is connected with the first direct current output end of the full-wave rectifying unit (11), and the third resistor (R3) and the fourth resistor (R4) are piezoresistors.
  7. 7. The starting auxiliary source circuit of a photovoltaic inverter according to any one of claims 2-6, characterized in that the number of the full-wave rectifying units (11) is two, respectively defined as a first full-wave rectifying unit (111) and a second full-wave rectifying unit (112), the number of the half-wave rectifying units (12) is two, respectively defined as a first half-wave rectifying unit (121) and a second half-wave rectifying unit (122), and the number of the alternating-current sources (13) of the starting auxiliary source circuit is two, respectively defined as a first alternating-current source (131) and a second alternating-current source (132); the alternating current input end of the first full-wave rectifying unit (111) is connected with a first alternating current source (131) of the starting auxiliary source circuit through the first half-wave rectifying unit (121); The alternating current input end of the second full-wave rectifying unit (112) is connected with a second alternating current source (132) of the starting auxiliary source circuit through the second half-wave rectifying unit (122); The first direct current output end of the first full-wave rectifying unit (111) is connected with the first direct current output end of the second full-wave rectifying unit (112), and the second direct current output end of the first full-wave rectifying unit (111) is connected with the second direct current output end of the second full-wave rectifying unit (112).
  8. 8. The starting auxiliary circuit of a photovoltaic inverter according to claim 7, characterized in that the conduction direction of the first half-wave rectifying unit (121) is opposite to the conduction direction of the second half-wave rectifying unit (122); The first half-wave rectifying unit (121) is a first diode (D1), and the second half-wave rectifying unit (122) is a second diode (D2); The first unidirectional conduction unit (17) is a third diode (D3).
  9. 9. A power supply circuit of a photovoltaic inverter, characterized by comprising a first auxiliary source circuit (2), a second auxiliary source circuit (1) and a voltage conversion circuit (3), wherein the second auxiliary source circuit (1) is the starting auxiliary source circuit according to any one of claims 1-8; The input end of the first auxiliary source circuit (2) receives battery voltage, the output end of the first auxiliary source circuit (2) is connected with the input end of the voltage conversion circuit (3) through a second unidirectional conduction unit (4), and the first auxiliary source circuit (2) is used for converting the battery voltage into a second power supply voltage; The second auxiliary source circuit (1) is used for outputting a first power supply voltage to the direct current bus (14), and the direct current bus (14) is connected with the input end of the voltage conversion circuit (3) through a third unidirectional conduction unit (5); when the second power supply voltage is larger than the bus voltage of the direct current bus (14), the second unidirectional conduction unit (4) is turned on, the third unidirectional conduction unit (5) is turned off, and the voltage conversion circuit (3) converts the second power supply voltage into one or more device power supply voltages and outputs the one or more device power supply voltages; When the bus voltage of the direct current bus (14) is larger than the second power supply voltage, the second unidirectional conduction unit (4) is turned off, the third unidirectional conduction unit (5) is turned on, and the voltage conversion circuit (3) converts the bus voltage of the direct current bus (14) into one or more device power supply voltages and outputs the one or more device power supply voltages.
  10. 10. The power supply circuit according to claim 9, characterized in that the first auxiliary source circuit (2) comprises a voltage detection circuit (21) and a first flyback circuit (22); The voltage detection circuit (21) is configured to output a feedback signal to the first flyback circuit (22) when the battery voltage is less than a first threshold value; The input end of the first flyback circuit (22) is connected with the input end of the first auxiliary source circuit (2), the output end of the first flyback circuit (22) is connected with the output end of the first auxiliary source circuit (2), the first flyback circuit (22) converts the battery voltage into the second power supply voltage, and the first flyback circuit (22) stops converting the battery voltage into the second power supply voltage under the condition of receiving a low-voltage signal.
  11. 11. The power supply circuit according to claim 9, wherein the voltage conversion circuit (3) comprises: A transformer (31) having a primary winding and a plurality of secondary windings, the primary winding having a first end connected to an input of the voltage conversion circuit (3), the plurality of secondary windings outputting a device power supply voltage, respectively; A second switching tube (Q2) having a first pole connected to a second end of the primary winding of the transformer (31); The pulse control circuit (32) is used for outputting a pulse signal and controlling the second switching tube (Q2) to be turned on or off so as to control the electric energy received by the input end of the voltage conversion circuit (3) to be converted from the primary side winding to the secondary side winding of the transformer (31); The input end of the feedback circuit (33) receives the power supply voltage of the device, the output end of the feedback circuit is connected with the feedback signal end of the pulse control circuit (32) and outputs a feedback signal, and the pulse control circuit (32) adjusts the duty ratio of the pulse signal according to the feedback signal; -a voltage divider circuit (34), the voltage divider circuit (34) being configured to divide a voltage when the pulse control circuit (32) is started to provide a starting voltage for the pulse control circuit (32); The voltage dividing circuit (34) comprises a first voltage dividing branch circuit (341) and a second voltage dividing branch circuit (342); The first end of the first voltage dividing branch circuit (341) is connected with a primary side winding of the transformer (31), and the second end of the first voltage dividing branch circuit (341) is connected with a starting voltage supply end of the pulse control circuit (32); The first end of the second voltage division branch (342) is connected with the starting voltage supply end of the pulse control circuit (32), the second end of the second voltage division branch (342) is grounded, the second voltage division branch (342) comprises at least two second voltage division units connected in series, and each second voltage division unit comprises at least two resistors connected in parallel.
  12. 12. A photovoltaic inverter comprising a start-up auxiliary source circuit according to any one of claims 1 to 8 or a power supply circuit according to any one of claims 9 to 11.

Description

Starting auxiliary source circuit, power supply circuit and photovoltaic inverter of photovoltaic inverter Technical Field The utility model belongs to the technical field of photovoltaic inverters, and particularly relates to a starting auxiliary source circuit, a power supply circuit and a photovoltaic inverter of the photovoltaic inverter. Background The photovoltaic inverter is a core device in a photovoltaic system, and has a main function of converting Direct Current (DC) generated by a solar panel into alternating Current (ALTERNATING CURRENT, AC) for use by household or industrial electrical equipment. Photovoltaic inverters have a dc bus with a voltage typically up to several hundred volts. The electric energy output by the photovoltaic module, the battery, the power grid or the generator is rectified, boosted and the like and then is converged into a direct current bus. The photovoltaic inverter inverts the direct current on the direct current bus into alternating current to be supplied to a load or be integrated into a power grid. The power supply circuit of the photovoltaic inverter generally takes power from a direct current bus to reduce the voltage, and outputs +15V, +12V, -12V, -15V and other voltages to supply power for different components in the photovoltaic inverter. However, when the photovoltaic inverter is started at first, the direct current bus has no voltage, and the photovoltaic inverter cannot take electricity from the direct current bus to start each component. The photovoltaic inverter therefore needs to draw electricity from the grid or the generator. Therefore, the starting auxiliary source circuit of the photovoltaic inverter takes two-phase line voltage as input from a power grid or a generator. The existing photovoltaic inverter carries out full-wave rectification treatment on the two phase line voltages and then sends the full-wave rectification treatment to a direct current bus to charge a bus capacitor. However, at the moment of starting the photovoltaic inverter, the bus capacitance of the direct current bus is similar to a short circuit, and because the voltage of the power grid is higher, huge surge current is easy to generate, so that the starting auxiliary source circuit bears larger stress, and the reliability and the service life of the starting auxiliary source circuit are reduced. Disclosure of utility model The starting auxiliary source circuit, the power supply circuit and the photovoltaic inverter provided by the embodiment of the application protect the starting auxiliary source circuit, and improve the reliability and the service life of the starting auxiliary source circuit. In a first aspect, an embodiment of the application provides a starting auxiliary source circuit of a photovoltaic inverter, which comprises a half-wave rectifying unit, a full-wave rectifying unit and a first unidirectional conduction unit, wherein an alternating current input end of the full-wave rectifying unit is connected with an alternating current source of the starting auxiliary source circuit through the half-wave rectifying unit, a direct current output end of the full-wave rectifying unit is connected with a direct current bus of the photovoltaic inverter through the first unidirectional conduction unit, and a direct current output end of the full-wave rectifying unit outputs a first power supply voltage to the direct current bus and uses the voltage of the direct current bus as a starting voltage of the photovoltaic inverter. The full-wave rectifying device comprises a full-wave rectifying unit, and is characterized by comprising a first direct-current output end and a second direct-current output end, wherein the direct-current output end of the full-wave rectifying unit comprises a first direct-current output end and a second direct-current output end, the first direct-current output end of the full-wave rectifying unit is connected with the first end of the switching unit through the first unidirectional conduction unit, the second end of the switching unit is connected with a positive bus of the direct-current bus, the third end of the switching unit is connected with the second direct-current output end of the full-wave rectifying unit, and the fourth end of the switching unit is connected with a negative bus of the direct-current bus. Optionally, the switch unit includes a multi-knife relay and a relay control module; the multi-knife relay comprises a driving piece, a first switch piece and a second switch piece, wherein the first end of the first switch piece is connected with the first end of the switch unit, the second end of the first switch piece is connected with the second end of the switch unit, the first end of the second switch piece is connected with the third end of the switch unit, the second end of the second switch piece is connected with the fourth end of the switch unit, the relay control module is connected with the first end of the driving piece, t