Auxiliary power supply system

Abstract

An auxiliary power supply system, provided in a converter and comprising a power-drawing unit and a power supply unit which are connected to each other. The power-drawing unit is separately connected to a power grid, a photovoltaic cell panel, and a battery in the converter; the power supply unit comprises a first power supply module, a second power supply module, and a third power supply module which are connected in parallel; the first power supply module comprises a first diode, the second power supply module comprises a second diode, and the third power supply module comprises a third diode; the power-drawing unit comprises a battery auxiliary power supply module, an AC auxiliary power supply module, and a bus capacitor module; a boost module is connected in series between the photovoltaic cell panel and the battery; a bidirectional isolation module is connected in series between the battery and the bus capacitor module; and an inverter module is connected in series between the bus capacitor module and the power grid. The auxiliary power supply system can realize energy transmission among an alternating current side of the power grid, a direct current side of a photovoltaic cell module, and the battery, thereby improving the reliability of the auxiliary power supply system.

Description

Auxiliary power supply system Related applications

[0001] This application claims priority to Chinese patent application No. CN2023108982799 filed on July 20, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure belongs to the field of converters, and particularly relates to an auxiliary power supply system. Background Art

[0003] Converters, such as integrated photovoltaic and energy storage devices, photovoltaic inverters, energy storage inverters, or mobile energy storage devices, typically have an auxiliary power supply system installed internally. The reliability of the auxiliary power supply system is crucial to the stable operation of the converter and is also a key component of the converter. Because converters have multiple operating modes, such as grid-connected, off-grid, and battery charging and discharging, existing auxiliary power supply systems can mostly draw power from both the AC side of the grid and the DC side of the photovoltaic cell module, or switch between AC and DC power supply according to different operating states. However, existing auxiliary power supply systems cannot achieve energy transmission between the AC side of the grid and the DC side of the photovoltaic cell module. If both the AC side of the grid and the DC side of the photovoltaic cell module lose power at the same time, the auxiliary power supply system will experience power outages or output voltage fluctuations, resulting in low reliability of the auxiliary power supply system. In addition, some auxiliary power supply systems require complex switching circuits, which are costly. Summary of the Invention

[0004] The present disclosure relates to an improved auxiliary power supply system.

[0005] A first aspect of the present disclosure provides an auxiliary power supply system, which is arranged inside a converter. The auxiliary power supply system includes a connected power supply unit and a power supply unit, wherein the power supply unit is respectively connected to a power grid, a photovoltaic panel, and a battery inside the converter; the power supply unit includes a first power supply module, a second power supply module, and a third power supply module connected in parallel, wherein the first power supply module includes a first diode, the second power supply module includes a second diode, and the third power supply module includes a third diode;

[0006] The power taking unit includes:

[0007] a battery auxiliary power module, wherein an input end of the battery auxiliary power module is connected to the battery, and an output end of the battery auxiliary power module is connected to the first diode;

[0008] an AC auxiliary power module, wherein an input end of the AC auxiliary power module is connected to the power grid, and an output end of the AC auxiliary power module is connected to the second diode;

[0009] A busbar capacitor module, wherein an output end of the busbar capacitor module is connected to the third diode;

[0010] A boost module connected in series between the photovoltaic panel and the battery;

[0011] a bidirectional isolation module connected in series between the battery and the bus capacitor module;

[0012] an inverter module connected in series between the bus capacitor module and the power grid;

[0013] The power supply unit further includes:

[0014] a DC auxiliary source module, wherein the input end of the DC auxiliary source module is connected to the first diode, the second diode, and the third diode respectively, and the output end of the DC auxiliary source module is connected to the device to be powered of the converter;

[0015] The highest voltage value among the battery auxiliary power module, the AC auxiliary power module and the bus capacitor module is used as the input value of the DC auxiliary power module.

[0016] In some embodiments, the auxiliary power supply system is configured to draw power from the grid side and transfer the energy of the grid to the battery for charging through the inverter module and the bidirectional isolation module, or to discharge the battery after passing through the boost module, the bidirectional isolation module and the inverter module in sequence, so that the energy of the photovoltaic panel and the battery is transferred to the grid.

[0017] In some embodiments, the auxiliary power supply system has at least one working mode, in which the DC auxiliary source module is configured to draw power from the bus capacitor module, and the battery auxiliary source module and the AC auxiliary source module operate at no load.

[0018] In some embodiments, the rated output voltage of the bus capacitor module is greater than the rated output voltage of the AC auxiliary power module, and the rated output voltage of the AC auxiliary power module is greater than the rated output voltage of the battery auxiliary power module.

[0019] In some embodiments, the rated output voltage of the bus capacitor module is 330V-460V, the rated output voltage of the AC auxiliary power module is 110V, and the rated output voltage of the battery auxiliary power module is 100V.

[0020] In some embodiments, the rated input voltage of the battery auxiliary power module is 30V-60V, and the rated input voltage of the AC auxiliary power module is 154V-276V.

[0021] In some embodiments, the bidirectional isolation module includes a DAB circuit, and the DAB circuit includes:

[0022] A primary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0023] A secondary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0024] an isolation transformer, connected to the primary full bridge and the secondary full bridge respectively;

[0025] A DAB inductor is connected to the primary full bridge and the isolation transformer respectively.

[0026] In some embodiments, the primary full bridge includes a first bridge arm, a second bridge arm, and a first bus capacitor connected in parallel, the first bridge arm includes a first switch module and a second switch module connected in series, and the second bridge arm includes a third switch module and a fourth switch module connected in series;

[0027] a secondary full bridge, comprising a third bridge arm, a fourth bridge arm, and a second bus capacitor connected in parallel, the third bridge arm comprising a fifth switch module and a sixth switch module connected in series, and the fourth bridge arm comprising a seventh switch module and an eighth switch module connected in series;

[0028] an isolation transformer, connected to the primary full bridge and the secondary full bridge, respectively, the isolation transformer comprising an isolation primary and an isolation secondary, one end of the isolation primary connected to a connection point between the third and fourth switch modules, one end of the isolation secondary connected to a connection point between the fifth and sixth switch modules, and the other end of the isolation secondary connected to a connection point between the seventh and eighth switch modules; the first, second, third, fourth, fifth, sixth, seventh, and eighth switch modules comprising diodes and power switches connected in parallel, the power switches being insulated gate bipolar transistors or MOS transistors;

[0029] A DAB inductor, one end of which is connected to the connection point between the first switch module and the second switch module, and the other end of which is connected to the other end of the isolation primary side.

[0030] In some embodiments, the inverter module includes a first inverter bridge arm and a second inverter bridge arm connected in parallel, the first inverter bridge arm includes a ninth switch module and a tenth switch module connected in series, and the second inverter bridge arm includes an eleventh switch module and a twelfth switch module connected in series; the ninth switch module, the tenth switch module, the eleventh switch module and the twelfth switch module include diodes and power switches connected in parallel, and the power switches are insulated gate bipolar transistors or MOS tubes.

[0031] In some embodiments, the power taking unit further includes a filter module, and the filter module is connected in series between the inverter module and the power grid;

[0032] The filter module includes a filter inductor and a filter capacitor, one end of the filter inductor is connected to the connection point of the ninth switch module and the tenth switch module, and the other end of the filter inductor is connected to the power grid; one end of the filter capacitor is connected to the connection point of the filter inductor and the power grid, and the other end of the filter capacitor is connected to the connection point of the eleventh switch module and the twelfth switch module.

[0033] In some embodiments, at least one grid-connected relay is connected in series between the filter module and the power grid.

[0034] In some embodiments, the DC auxiliary power module includes a step-down circuit.

[0035] In some embodiments, the boost module includes a Boost boost circuit, and the Boost boost circuit includes a Boost input capacitor, a Boost switch module, a Boost output capacitor, a Boost inductor, and a Boost diode;

[0036] One end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the Boost inductor, and the other end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the battery;

[0037] One end of the Boost switch module is connected to the connection point between the Boost inductor and the Boost diode, and the other end of the Boost switch module is connected to the connection point between the photovoltaic panel and the battery;

[0038] One end of the Boost output capacitor is connected to the connection point between the Boost diode and the battery, and the other end of the Boost output capacitor is connected to the connection point between the photovoltaic panel and the battery;

[0039] One end of the Boost inductor is connected to the photovoltaic panel, and the other end of the Boost inductor is connected to the Boost diode;

[0040] One end of the Boost diode is connected to the Boost inductor, and the other end of the Boost diode is connected to the battery.

[0041] In some embodiments, the Boost switch module includes a diode and a power switch connected in parallel, the power switch is an insulated gate bipolar transistor or a MOS transistor; and the Boost diode is a Schottky diode.

[0042] In some embodiments, the converter is a photovoltaic storage device, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device.

[0043] In some embodiments, the device to be powered includes a control system of the converter, a drive transformer, a relay, a monitoring board or a WIFI stick.

[0044] The auxiliary power supply system disclosed in the present invention, because a bidirectional isolation module is connected in series between the battery and the busbar capacitor module, can transmit the energy of the power grid to the battery for charging after the topological rectification of the inverter module on the AC side of the power grid and the bidirectional isolation module; a boost module is also provided between the photovoltaic panel and the battery, and the battery can be discharged after the boost through the bidirectional isolation module and the inverter module, so that the energy of the photovoltaic panel and the built-in battery can be transmitted to the subsequent AC power grid. The auxiliary power supply system can simultaneously draw power from the power grid, the photovoltaic panel and the battery in the converter, and use the parallel diode competitive power supply method. The highest voltage value among the three is used as the input of the DC auxiliary source module, and finally the DC auxiliary source module outputs the voltage to the device to be powered. When the voltage of the photovoltaic panel side, the battery side or the AC side power grid fails for some reason, the auxiliary power supply system will not experience power failure or output voltage fluctuation, thereby improving the reliability of the auxiliary power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solution of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] FIG1 is a connection diagram of an auxiliary power supply system according to an embodiment of the present disclosure;

[0047] FIG2 is another connection diagram of the auxiliary power supply system according to an embodiment of the present disclosure;

[0048] Among them, 11-photovoltaic panel; 12-battery; 13-grid; 2-power supply unit; 21-battery auxiliary power module; 22-AC auxiliary power module; 23-bus capacitor module; 24-boost module; 25-bidirectional isolation module; 251-primary full bridge; 252-secondary full bridge; 253-isolation transformer; L1-DAB inductor; C1-first bus capacitor; C2-second bus capacitor; T1-first switch module; T2-second switch module; T3-third switch module; T4-fourth switch module; T5-fifth switch module; T6-sixth switch module; T7-seventh switch module; T8-eighth switch module; T9-ninth switch Switch module; T10-10th switch module; T11-11th switch module; T12-12th switch module; 26-inverter module; 27-filter module; L2-filter inductor; C3-filter capacitor; 28-grid-connected relay; C4-Boost input capacitor; C5-Boost output capacitor; T13-Boost switch module; L3-Boost inductor; D1-Boost diode; 3-power supply unit; 31-DC auxiliary source module; 4-first power supply module; 41-first diode; 5-second power supply module; 51-second diode; 6-third power supply module; 61-third diode; 7-device to be powered. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present disclosure are described in detail below with reference to the accompanying drawings to make the advantages and features of the present disclosure more easily understood by those skilled in the art. It should be noted that the descriptions of these embodiments are intended to facilitate understanding of the present disclosure and do not constitute a limitation of the present disclosure. In addition, the technical features involved in the various embodiments of the present disclosure described below may be combined with each other as long as they do not conflict with each other.

[0050] As shown in Figures 1 and 2, this embodiment discloses an auxiliary power supply system, which is arranged inside the converter. The converter can be a photovoltaic storage integrated machine, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device, which is not limited here. Among them, the auxiliary power supply system includes a power supply unit 2 and a power supply unit 3 connected in series. The power supply unit 2 is respectively connected to the power grid 13, the photovoltaic panel 11 and the battery 12 in the converter, that is, the system can simultaneously draw power from the AC side of the power grid, the DC side of the photovoltaic panel and the built-in battery of the converter. The power supply unit 3 includes a first power supply module 4, a second power supply module 5 and a third power supply module 6 connected in parallel. The first power supply module 4 includes a first diode 41, the second power supply module 5 includes a second diode 51, and the third power supply module 6 includes a third diode 61. The power supply unit 3 also includes a DC auxiliary source module 31. The input end of the DC auxiliary source module 31 is respectively connected to the first diode 41, the second diode 51 and the third diode 61, and the output end of the DC auxiliary source module 31 is connected to the power supply device 7 of the converter.

[0051] As shown in Figure 1, the power supply unit 2 includes a battery auxiliary source module 21, an AC auxiliary source module 22, and a bus capacitor module 23. The input end of the battery auxiliary source module 21 is connected to the battery 12, and the output end of the battery auxiliary source module 21 is connected to the first diode 41. The input end of the AC auxiliary source module 22 is connected to the power grid 13, and the output end of the AC auxiliary source module 22 is connected to the second diode 51. The output end of the bus capacitor module 23 is connected to the third diode 61. Through the parallel diode competitive power supply method, the highest voltage value among the battery auxiliary source module 21, the AC auxiliary source module 22, and the bus capacitor module 23 is used as the input of the DC auxiliary source module 31. When a fault occurs on the grid side, the battery side, or the DC side of the photovoltaic module, the auxiliary power supply system will not experience power outages or output voltage fluctuations, thereby improving the reliability of the auxiliary power supply system. In this embodiment, the rated output voltage of the bus capacitor module 23 is greater than the rated output voltage of the AC auxiliary source module 22, and the rated output voltage of the AC auxiliary source module 22 is greater than the rated output voltage of the battery auxiliary source module 21. For example, the rated output voltage of the bus capacitor module 23 can be 330V-460V, the rated output voltage of the AC auxiliary power module 22 can be 110V, and the rated output voltage of the battery auxiliary power module 21 can be 100V. Under normal operating conditions, the DC auxiliary power module 31 draws power directly from the bus capacitor module 23, while the other two battery auxiliary power modules 21 and the AC auxiliary power module 22 operate at no load (i.e., no output current). The single-stage auxiliary power operation scheme improves system efficiency compared to the two-stage operation scheme. Since the rated output voltage of the AC auxiliary power module 22 is set to 110V and the rated output voltage of the battery auxiliary power module 21 is set to 100V, the lower output voltage helps reduce the number of winding turns and the size of the magnetic core, thereby reducing costs and optimizing size.

[0052] The power supply unit 2 also includes a boost module 24, a bidirectional isolation module 25, an inverter module 26, and a filter module 27. Specifically, the boost module 24 is connected in series between the photovoltaic panel 11 and the battery 12. The bidirectional isolation module 25 is connected in series between the battery 12 and the bus capacitor module 23, the inverter module 26 is connected in series between the bus capacitor module 23 and the power grid 13, and the filter module 27 is connected in series between the inverter module 26 and the power grid 13. The auxiliary power supply system is configured to draw power from the grid side and transfer the grid energy to the battery for charging through the inverter module 26 and the bidirectional isolation module 25, or to discharge the battery after passing through the boost module 24, the bidirectional isolation module 25, and the inverter module 26 in sequence, so that the energy of the photovoltaic panel and the battery is transferred to the power grid.

[0053] The bidirectional isolation module 25 specifically includes a dual active bridge (DAB) circuit, which includes a primary full bridge 251, a secondary full bridge 252, an isolation transformer 253, and a DAB inductor L1. The isolation transformer 253 is connected to the primary full bridge 251 and the secondary full bridge 252, respectively. The DAB inductor L1 is connected to the primary full bridge 251 and the isolation transformer 253, respectively. Specifically, the primary full bridge 251 includes a first bridge arm, a second bridge arm, and a first bus capacitor C1 connected in parallel. The first bridge arm includes a first switch module T1 and a second switch module T2 connected in series, while the second bridge arm includes a third switch module T3 and a fourth switch module T4 connected in series. The secondary full bridge 252 includes a third bridge arm, a fourth bridge arm, and a second bus capacitor C2 connected in parallel. The third bridge arm includes a fifth switch module T5 and a sixth switch module T6 connected in series, while the fourth bridge arm includes a seventh switch module T7 and an eighth switch module T8 connected in series. The isolation transformer 253 is connected to the primary full bridge 251 and the secondary full bridge 252, respectively. The isolation transformer includes an isolated primary and an isolated secondary. One end of the isolated primary is connected to the connection point between the third switch module T3 and the fourth switch module T4. One end of the isolated secondary is connected to the connection point between the fifth switch module T5 and the sixth switch module T6. The other end of the isolated secondary is connected to the connection point between the seventh switch module T7 and the eighth switch module T8. The first switch module T1, the second switch module T2, the third switch module T3, the fourth switch module T4, the fifth switch module T5, the sixth switch module T6, the seventh switch module T7, and the eighth switch module T8 include parallel-connected diodes and power switches, each of which is an insulated gate bipolar transistor (MOS transistor). One end of the DAB inductor L1 is connected to the connection point between the first switch module T1 and the second switch module T2, and the other end of the DAB inductor L1 is connected to the other end of the isolated primary.

[0054] Inverter module 26 includes a first inverter bridge arm and a second inverter bridge arm connected in parallel. The first inverter bridge arm includes a ninth switch module T9 and a tenth switch module T10 connected in series, while the second inverter bridge arm includes an eleventh switch module T11 and a twelfth switch module T12 connected in series. The ninth, tenth, eleventh, and twelfth switch modules T9, T10, T11, and T12 each include a diode and a power switch connected in parallel. The power switch is an insulated gate bipolar transistor (MOSFET) or MOS transistor.

[0055] The filter module 27 includes a filter inductor L2 and a filter capacitor C3. One end of the filter inductor L2 is connected to the connection point between the ninth switch module T9 and the tenth switch module T10, and the other end of the filter inductor L2 is connected to the power grid 13. One end of the filter capacitor C3 is connected to the connection point between the filter inductor L2 and the power grid 13, and the other end of the filter capacitor C3 is connected to the connection point between the eleventh switch module T11 and the twelfth switch module T12.

[0056] Boost module 24 includes a boost circuit, which includes a boost input capacitor C4, a boost switch module T13, a boost output capacitor C5, a boost inductor L3, and a boost diode D1. One end of boost input capacitor C4 is connected to the junction between photovoltaic panel 11 and boost inductor L3, while the other end is connected to the junction between photovoltaic panel 11 and battery 12. One end of boost switch module T13 is connected to the junction between boost inductor L3 and boost diode D1, while the other end is connected to the junction between photovoltaic panel 11 and battery 12. One end of boost output capacitor C5 is connected to the junction between boost diode D1 and battery 12, while the other end is connected to the junction between photovoltaic panel 11 and battery 12. One end of boost inductor L3 is connected to photovoltaic panel 11, while the other end is connected to boost diode D1. One end of boost diode D1 is connected to boost inductor L3, while the other end is connected to battery 12. The boost switch module T13 includes a diode and a power switch connected in parallel. The power switch is an insulated gate bipolar transistor (MOSFET). The boost diode D1 is a Schottky diode, which primarily serves as an isolation device in the boost circuit. When the photovoltaic panel 11 is powered, the boost diode D1 transmits the voltage from the photovoltaic panel 11 to the input of the battery auxiliary power module 21. When this voltage meets the rated input voltage range of the battery auxiliary power module 21, the battery auxiliary power module 21 and the DC auxiliary power module 31 can continue to operate normally, even if the battery 12 and the grid 13 are depleted.

[0057] The boost circuit primarily transfers energy from the photovoltaic panel 11 to the battery within the inverter and the downstream AC grid. The DAB circuit utilizes a bidirectional topology, allowing grid energy to be transferred to the battery for charging via the DAB circuit after rectification via the inverter circuit topology. It can also discharge the battery through the DAB circuit and inverter circuit, transferring energy to the AC grid. Because the auxiliary power supply is low, a flyback scheme is employed. The high-frequency common-mode voltage fluctuations are isolated by the flyback transformer, eliminating any interfering return paths. This effectively reduces the system's conducted and radiated interference levels. With a low component count and low power consumption, the cost is relatively low. The input terminals of the battery auxiliary power module 21 are connected to BATV+ and BATV-, with a rated input voltage range of 30V-60V and a rated output voltage of 100V. The input terminals of the AC auxiliary power module 22 are connected to ACL and ACN, with a rated input voltage range of 154V-276V and a rated output voltage of 110V. This wide input voltage range ensures that the AC auxiliary power module 22 can operate normally even when the grid voltage fluctuates significantly. Therefore, when the battery auxiliary power module 21 and the AC auxiliary power module 22 are connected at the same time, the grid is given priority for power supply through the parallel competitive diode power supply scheme, thereby avoiding excessive discharge of the battery.

[0058] At least one AC grid-connected relay 28 is also connected in series between the filter module 27 and the power grid 13. The DC auxiliary source module 31 is also equipped with a step-down circuit to prevent the output voltage from being too high and burning out the power supply device 7 at the back end. The input voltage range of the DC auxiliary source module 31 is 80-500V. This wide voltage range ensures that the DC auxiliary source module 31 can operate normally when the bus voltage is high due to special operating conditions such as high voltage ride-through. Since the minimum input voltage of the DC auxiliary source module 31 needs to be less than the rated output voltage of the battery auxiliary source module 21, it is set to 80V. At the same time, setting it to 80V also ensures that the bus voltage can be quickly discharged and clamped to a lower voltage value when the converter is shut down. The power supply device 7 can be the converter's control system, drive transformer, relay, monitoring board, or WIFI stick, etc. The WIFI stick is a communication device based on the WIFI network. It connects to the cloud server at the upper layer and the converter at the lower layer. Its main function is to transmit the converter data to the cloud server via the WIFI network. Specifically in this embodiment, the DC auxiliary power module 31 can output 12V to power the control system and 7V to supply the coil voltage of the grid-connected relay and soft-start relay after they are energized, thereby reducing coil losses. The DC auxiliary power module 31 can also power the MOS or IGBT driver power supply through a forward transformer. This forward circuit does not require an energy storage inductor, so the driver power supply voltage is only related to the output voltage of the auxiliary winding of the DC auxiliary power module 31 and has little effect on the pulse width, ensuring relative stability of the driver power supply voltage.

[0059] The auxiliary power supply system in the above embodiment has the following advantages:

[0060] 1. Because a bidirectional isolation module is connected in series between the battery and busbar capacitor module, grid energy can be transferred to the battery for charging via the bidirectional isolation module after topological rectification by the inverter module on the AC side of the grid. A boost module is also provided between the photovoltaic panel and the battery, which can also discharge the battery after boosting through the bidirectional isolation module and inverter module, allowing energy from the photovoltaic panel and built-in battery to be transferred to the downstream AC grid.

[0061] 2. The auxiliary power supply system can simultaneously draw power from the grid, photovoltaic panels, and the battery in the converter. Through a parallel diode competitive power supply method, the highest voltage among the three is used as the input of the DC auxiliary power module, which ultimately outputs the voltage to the device to be powered. This prevents power outages and output voltage fluctuations in the auxiliary power supply system, thereby improving the reliability of the auxiliary power supply system.

[0062] 3. Under normal operating conditions, the DC auxiliary power module draws power directly from the bus capacitor module, while the other two battery auxiliary power modules and the AC auxiliary power module operate at no load. This single-stage auxiliary power operation solution improves system efficiency compared to the dual-stage operation solution.

[0063] 4. The rated output voltage of the AC auxiliary power module and the battery auxiliary power module is lower. The lower output voltage helps reduce the number of winding turns and the size of the magnetic core, thereby reducing costs and optimizing size.

[0064] 5. When the inverter module is operating, a high-frequency common-mode voltage will exist between HVBUS+ and HVBUS- and ground. This high-frequency common-mode voltage will cause strong conducted and radiated interference to the system. Therefore, the AC auxiliary power module 22, the battery auxiliary power module 21, and the DC auxiliary power module 31 all adopt a flyback solution. The high-frequency common-mode voltage is isolated by the flyback transformer, eliminating the interference return path, which can effectively reduce the conducted and radiated interference level of the system.

[0065] Features of embodiments of the present disclosure are set forth in the following clauses:

[0066] 1. An auxiliary power supply system disposed within a converter, the auxiliary power supply system comprising a power extraction module and a power supply module connected in series, the power extraction module being respectively connected to a power grid, a photovoltaic panel, and a battery within the converter; the power supply module comprising a first power supply module, a second power supply module, and a third power supply module connected in parallel, the first power supply module including a first diode, the second power supply module including a second diode, and the third power supply module including a third diode;

[0067] in,

[0068] The power taking module includes:

[0069] a battery auxiliary power module, wherein an input end of the battery auxiliary power module is connected to the battery, and an output end of the battery auxiliary power module is connected to the first diode;

[0070] an AC auxiliary power module, wherein an input end of the AC auxiliary power module is connected to the power grid, and an output end of the AC auxiliary power module is connected to the second diode;

[0071] A busbar capacitor module, wherein an output end of the busbar capacitor module is connected to the third diode;

[0072] A boost module is connected in series between the photovoltaic panel and the battery, a bidirectional isolation module is connected in series between the battery and the bus capacitor module, and an inverter module is connected in series between the bus capacitor module and the power grid;

[0073] The power supply module also includes a DC auxiliary source module, the input end of the DC auxiliary source module is connected to the first diode, the second diode and the third diode respectively, and the output end of the DC auxiliary source module is connected to the device to be powered of the converter.

[0074] 2. The auxiliary power supply system according to clause 1, wherein the rated output voltage of the bus capacitor module is greater than the rated output voltage of the AC auxiliary power module, and the rated output voltage of the AC auxiliary power module is greater than the rated output voltage of the battery auxiliary power module.

[0075] 3. The auxiliary power supply system according to clause 2, wherein the rated output voltage of the bus capacitor module is 330V-460V, the rated output voltage of the AC auxiliary power module is 110V, and the rated output voltage of the battery auxiliary power module is 100V.

[0076] 4. The auxiliary power supply system according to clause 3, wherein the rated input voltage of the battery auxiliary power module is 30V-60V, and the rated input voltage of the AC auxiliary power module is 154V-276V.

[0077] 5. The auxiliary power supply system according to clause 1, wherein the bidirectional isolation module comprises a DAB circuit, wherein the DAB circuit comprises:

[0078] A primary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0079] A secondary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0080] an isolation transformer, connected to the primary full bridge and the secondary full bridge respectively;

[0081] A DAB inductor is connected to the primary full bridge and the isolation transformer respectively.

[0082] 6. The auxiliary power supply system according to clause 5, wherein the primary full bridge comprises a first bridge arm, a second bridge arm, and a first bus capacitor connected in parallel, the first bridge arm comprises a first switch module and a second switch module connected in series, and the second bridge arm comprises a third switch module and a fourth switch module connected in series;

[0083] a secondary full bridge, comprising a third bridge arm, a fourth bridge arm, and a second bus capacitor connected in parallel, the third bridge arm comprising a fifth switch module and a sixth switch module connected in series, and the fourth bridge arm comprising a seventh switch module and an eighth switch module connected in series;

[0084] an isolation transformer, connected to the primary full bridge and the secondary full bridge, respectively, the isolation transformer comprising an isolation primary and an isolation secondary, one end of the isolation primary connected to a connection point between the third and fourth switch modules, one end of the isolation secondary connected to a connection point between the fifth and sixth switch modules, and the other end of the isolation secondary connected to a connection point between the seventh and eighth switch modules; the first, second, third, fourth, fifth, sixth, seventh, and eighth switch modules comprising diodes and power switches connected in parallel, the power switches being insulated gate bipolar transistors or MOS transistors;

[0085] A DAB inductor, one end of which is connected to the connection point between the first switch module and the second switch module, and the other end of which is connected to the other end of the isolation primary side.

[0086] 7. An auxiliary power supply system according to clause 1, wherein the inverter module includes a first inverter bridge arm and a second inverter bridge arm connected in parallel, the first inverter bridge arm includes a ninth switch module and a tenth switch module connected in series, and the second inverter bridge arm includes an eleventh switch module and a twelfth switch module connected in series; the ninth switch module, the tenth switch module, the eleventh switch module and the twelfth switch module include diodes and power switches connected in parallel, and the power switches are insulated gate bipolar transistors or MOS tubes.

[0087] 8. The auxiliary power supply system according to clause 7, wherein the power extraction module further comprises a filter module, wherein the filter module is connected in series between the inverter module and the power grid;

[0088] The filter module includes a filter inductor and a filter capacitor, one end of the filter inductor is connected to the connection point of the ninth switch module and the tenth switch module, and the other end of the filter inductor is connected to the power grid; one end of the filter capacitor is connected to the connection point of the filter inductor and the power grid, and the other end of the filter capacitor is connected to the connection point of the eleventh switch module and the twelfth switch module.

[0089] 9. The auxiliary power supply system according to clause 8, wherein at least one grid-connected relay is connected in series between the filter module and the power grid.

[0090] 10. The auxiliary power supply system according to clause 1, wherein the DC auxiliary power module includes a step-down circuit.

[0091] 11. The auxiliary power supply system according to clause 1, wherein the boost module comprises a boost circuit, and the boost circuit comprises a boost input capacitor, a boost switch module, a boost output capacitor, a boost inductor, and a boost diode;

[0092] One end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the Boost inductor, and the other end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the battery;

[0093] One end of the Boost switch module is connected to the connection point between the Boost inductor and the Boost diode, and the other end of the Boost switch module is connected to the connection point between the photovoltaic panel and the battery;

[0094] One end of the Boost output capacitor is connected to the connection point between the Boost diode and the battery, and the other end of the Boost output capacitor is connected to the connection point between the photovoltaic panel and the battery;

[0095] One end of the Boost inductor is connected to the photovoltaic panel, and the other end of the Boost inductor is connected to the Boost diode;

[0096] One end of the Boost diode is connected to the Boost inductor, and the other end of the Boost diode is connected to the battery.

[0097] 12. The auxiliary power supply system according to clause 11, wherein the boost switch module comprises a diode and a power switch connected in parallel, the power switch is an insulated gate bipolar transistor or a MOS transistor; and the boost diode is a Schottky diode.

[0098] 13. The auxiliary power supply system according to clause 1, wherein the converter is a photovoltaic storage device, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device; and the device to be powered includes a control system, a drive transformer, a relay, a monitoring board or a WiFi stick of the converter.

[0099] As shown in this specification and claims, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0100] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a", "the" and "the" used herein may also include plural forms. It is further understood that "a plurality" in this disclosure refers to two or more, and other quantifiers are similar thereto.

[0101] It will be further understood that the terms "first," "second," and the like are used to describe various types of information, but such information should not be limited to these terms. These terms are used solely to distinguish information of the same type from one another and do not indicate a particular order or level of importance. In fact, the terms "first," "second," and the like are fully interchangeable. For example, first information could be referred to as second information, and similarly, second information could be referred to as first information without departing from the scope of this disclosure.

[0102] The above embodiment is only for illustrating the technical concept and features of the present disclosure and is a preferred embodiment. Its purpose is to enable people familiar with this technology to understand the content of the present disclosure and implement it accordingly, and it cannot be used to limit the scope of protection of the present disclosure.

Claims

1. An auxiliary power supply system, which is arranged inside a converter, the auxiliary power supply system comprises a connected power supply unit and a power supply unit, the power supply unit is respectively connected to a power grid, a photovoltaic panel and a battery in the converter; the power supply unit comprises a first power supply module, a second power supply module and a third power supply module connected in parallel, the first power supply module comprises a first diode, the second power supply module comprises a second diode, and the third power supply module comprises a third diode; It is characterized in that The power taking unit comprises: A battery auxiliary source module, wherein an input end of the battery auxiliary source module is connected to the battery, and an output end of the battery auxiliary source module is connected to the first diode; An AC auxiliary source module, wherein an input end of the AC auxiliary source module is connected to the power grid, and an output end of the AC auxiliary source module is connected to the second diode; A bus capacitor module, wherein an output end of the bus capacitor module is connected to the third diode; A boost module, which is connected in series between the photovoltaic panel and the battery; A bidirectional isolation module, which is connected in series between the battery and the bus capacitor module; An inverter module, which is connected in series between the bus capacitor module and the power grid; The power supply unit further includes: A DC auxiliary source module, wherein the input end of the DC auxiliary source module is respectively connected to the first diode, the second diode and the third diode, and the output end of the DC auxiliary source module is connected to the device to be powered of the converter; The highest voltage value among the battery auxiliary source module, the AC auxiliary source module and the bus capacitor module is used as the input value of the DC auxiliary source module.

2. The auxiliary power supply system according to claim 1, characterized in that: The auxiliary power supply system is configured to take power from the grid side and transfer the energy of the grid to the battery for charging through the inverter module and the bidirectional isolation module, and can also discharge the battery after passing through the boost module, the bidirectional isolation module and the inverter module in sequence, so that the energy of the photovoltaic panel and the battery is transferred to the grid.

3. The auxiliary power supply system according to claim 1, characterized in that: The auxiliary power supply system has at least one working mode, in which the DC auxiliary source module is configured to draw power from the bus capacitor module, and the battery auxiliary source module and the AC auxiliary source module operate at no load.

4. The auxiliary power supply system according to claim 1, characterized in that: The rated output voltage of the bus capacitor module is greater than the rated output voltage of the AC auxiliary source module, and the rated output voltage of the AC auxiliary source module is greater than the rated output voltage of the battery auxiliary source module.

5. The auxiliary power supply system according to claim 4, characterized in that: The rated output voltage of the bus capacitor module is 330V-460V, the rated output voltage of the AC auxiliary source module is 110V, and the rated output voltage of the battery auxiliary source module is 100V.

6. The auxiliary power supply system according to claim 5, characterized in that: The rated input voltage of the battery auxiliary power module is 30V-60V, and the rated input voltage of the AC auxiliary power module is 154V-276V.

7. The auxiliary power supply system according to claim 1, characterized in that: The bidirectional isolation module includes a DAB circuit, and the DAB circuit includes: A primary full bridge, comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series; A secondary full bridge, comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series; an isolation transformer, connected to the primary full bridge and the secondary full bridge respectively; The DAB inductor is connected to the primary full bridge and the isolation transformer respectively.

8. The auxiliary power supply system according to claim 7, characterized in that: The primary full bridge comprises a first bridge arm, a second bridge arm and a first bus capacitor connected in parallel, the first bridge arm comprises a first switch module and a second switch module connected in series, and the second bridge arm comprises a third switch module and a fourth switch module connected in series; A secondary full bridge, comprising a third bridge arm, a fourth bridge arm and a second bus capacitor connected in parallel, the third bridge arm comprising a fifth switch module and a sixth switch module connected in series, and the fourth bridge arm comprising a seventh switch module and an eighth switch module connected in series; an isolation transformer, which is respectively connected to the primary full bridge and the secondary full bridge, the isolation transformer comprising an isolation primary and an isolation secondary, one end of the isolation primary is connected to a connection point between the third switch module and the fourth switch module, one end of the isolation secondary is connected to a connection point between the fifth switch module and the sixth switch module, and the other end of the isolation secondary is connected to a connection point between the seventh switch module and the eighth switch module; the first switch module, the second switch module, the third switch module, the fourth switch module, the fifth switch module, the sixth switch module, the seventh switch module and the eighth switch module comprise diodes and power switches connected in parallel with each other, and the power switch is an insulated gate bipolar transistor or a MOS tube; A DAB inductor, one end of which is connected to a connection point between the first switch module and the second switch module, and the other end of which is connected to the other end of the isolation primary side.

9. The auxiliary power supply system according to claim 1, characterized in that: The inverter module includes a first inverter bridge arm and a second inverter bridge arm connected in parallel, the first inverter bridge arm includes a ninth switch module and a tenth switch module connected in series, and the second inverter bridge arm includes an eleventh switch module and a twelfth switch module connected in series; the ninth switch module, the tenth switch module, the eleventh switch module and the twelfth switch module include diodes and power switches connected in parallel, and the power switch is an insulated gate bipolar transistor or a MOS tube.

10. The auxiliary power supply system according to claim 9, characterized in that: The power taking unit further includes a filter module, which is connected in series between the inverter module and the power grid; The filter module includes a filter inductor and a filter capacitor, one end of the filter inductor is connected to the connection point of the ninth switch module and the tenth switch module, and the other end of the filter inductor is connected to the power grid; one end of the filter capacitor is connected to the connection point of the filter inductor and the power grid, and the other end of the filter capacitor is connected to the connection point of the eleventh switch module and the twelfth switch module.

11. The auxiliary power supply system according to claim 10, characterized in that: At least one grid-connected relay is also connected in series between the filter module and the power grid.

12. The auxiliary power supply system according to claim 1, characterized in that: The DC auxiliary source module includes a step-down circuit.

13. The auxiliary power supply system according to claim 1, characterized in that: The boost module includes a Boost boost circuit, and the Boost boost circuit includes a Boost input capacitor, a Boost switch module, a Boost output capacitor, a Boost inductor and a Boost diode; One end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the Boost inductor, and the other end of the Boost input capacitor is connected to the connection point between the photovoltaic panel and the battery; One end of the Boost switch module is connected to a connection point between the Boost inductor and the Boost diode, and the other end of the Boost switch module is connected to a connection point between the photovoltaic panel and the battery; One end of the Boost output capacitor is connected to the connection point between the Boost diode and the battery, and the other end of the Boost output capacitor is connected to the connection point between the photovoltaic panel and the battery; One end of the Boost inductor is connected to the photovoltaic panel, and the other end of the Boost inductor is connected to the Boost diode; One end of the Boost diode is connected to the Boost inductor, and the other end of the Boost diode is connected to the battery.

14. The auxiliary power supply system according to claim 13, characterized in that: The Boost switch module comprises a diode and a power switch connected in parallel with each other, wherein the power switch is an insulated gate bipolar transistor or a MOS tube; and the Boost diode is a Schottky diode.

15. The auxiliary power supply system according to claim 1, characterized in that: The converter is a photovoltaic and energy storage integrated machine, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device.

16. The auxiliary power supply system according to claim 1, characterized in that: The device to be powered includes a control system, a drive transformer, a relay, a monitoring board or a WIFI stick of the converter.

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