A bidirectional inverter and photovoltaic inverter system

Abstract

The bidirectional inverter and photovoltaic inverter system provided in this application are based on the bidirectional inverter provided in this application. The bidirectional inverter includes a rectifier circuit, a transformer, and a frequency conversion circuit. The rectifier circuit is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer, or to rectify the AC signal output from the primary side of the transformer into an external DC signal and output it. The frequency conversion circuit is used to adjust the frequency of the AC signal output from the secondary side of the transformer, or to adjust the frequency of the received AC signal. By setting a voltage regulator module in the frequency conversion bridge arm, the received AC signal is partially converted into a stable voltage, and the obtained stable voltage is used to power the switching device driver, eliminating the need for an auxiliary power supply and reducing the hardware cost of the bidirectional inverter.

Description

Technical Field

[0001] This application relates to the field of circuit control technology, and in particular to a bidirectional inverter and a photovoltaic inverter system. Background Technology

[0002] In recent years, with the popularization of renewable energy, the demand for new energy power systems has been increasing.

[0003] Existing new energy power systems typically require the use of bidirectional inverter systems to achieve grid-connected power generation or convenient electricity use, which places higher demands on existing bidirectional inverter systems.

[0004] In the process of conceiving and implementing this application, the inventors discovered at least the following problems: the circuits of current bidirectional inverters are complex, and most of them contain a large number of auxiliary sources as isolated auxiliary power supplies, resulting in high hardware costs, which are technical problems that urgently need to be solved by those skilled in the art.

[0005] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the Invention

[0006] The main objective of this application is to propose a bidirectional inverter and a photovoltaic inverter system. The bidirectional inverter includes a rectifier circuit (10), a transformer (20), and a frequency conversion circuit (30). The rectifier circuit (10) is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer (20), or to rectify the AC signal output from the primary side of the transformer (20) into an external DC signal and output it. The frequency conversion circuit (30) is used to adjust the frequency of the AC signal output from the secondary side of the transformer (20), or to adjust the frequency of the received AC signal. The frequency conversion circuit (30) includes a junction... The first frequency conversion bridge arm (301a) and the second frequency conversion bridge arm (301b) have the same structure. The input terminal of the first frequency conversion bridge arm (301a) is connected to the output terminal and the first terminal of the secondary side of the second frequency conversion bridge arm (301b). The output terminal of the first frequency conversion bridge arm (301a) is connected to the input terminal and the second terminal of the secondary side of the second frequency conversion bridge arm (301b). The first frequency conversion bridge arm (301a) includes a bridge arm circuit (3011a) and a switching device driver (3012a). The bridge arm circuit (3011a) includes a switching device (30111a) and a first diode. The circuit consists of a diode (30112), a second diode (30113), a first voltage divider capacitor (30114), a second voltage divider capacitor (30115), and a voltage regulator module (30116). One end of the first voltage divider capacitor (30114) serves as the input terminal of the first frequency conversion bridge arm (301a). The other end of the first voltage divider capacitor (30114) is connected to the anode of the first diode (30112). The cathode of the first diode (30112) is connected to the anode of the second diode (30113). The cathode of the second diode (30113) is connected through the second voltage divider capacitor (30115). The first path terminal of the switch (30111a) is connected to the second path terminal of the switch (30111a), which serves as the output terminal of the first frequency conversion bridge arm (301a). The input terminal of the voltage regulator module (30116) is connected to the anode of the second diode (30113), and the output terminal of the voltage regulator module (30116) is connected to the cathode of the second diode (30113). The output terminal of the voltage regulator module (30116) is also connected to the power supply terminal of the switch driver (3012a), and the drive output terminal of the switch driver (3012a) is connected to the control terminal of the switch (30111a).

[0007] Preferably, the frequency conversion circuit (30) further includes a first filter capacitor (302); the input terminal of the bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the output terminal is connected to the second end of the secondary side of the transformer (20) through the first filter capacitor (302); the output terminal of the bridge arm circuit (3011b) of the second frequency conversion bridge arm (301b) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the input terminal is connected to the second end of the secondary side of the transformer (20) through the first filter capacitor (302).

[0008] Preferably, the first path terminals of the switching elements (30111a, 30111b) of the first frequency conversion bridge arm (301a) and the second frequency conversion bridge arm (301b) are interconnected.

[0009] Preferably, the bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) further includes at least one leakage protection diode (30117a), the anode of the leakage protection diode (30117a) is connected to the first pass terminal of the switching element (30111a), and the cathode of the leakage protection diode (30117a) is connected to the input terminal of the bridge arm circuit (3011a).

[0010] Preferably, the bidirectional inverter further includes a third frequency conversion bridge arm (301c), a fourth frequency conversion bridge arm (301d), and a second filter capacitor (302*); wherein the internal structure of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) is the same as that of the first frequency conversion bridge arm (301a). Furthermore, the input terminal of the bridge arm circuit (3011c) of the third frequency conversion bridge arm (301c) is connected to the first end of the secondary side of the transformer (20), and the output terminal is connected to the second end of the secondary side of the transformer (20) through the second filter capacitor (302*); the output terminal of the bridge arm circuit (3011d) of the fourth frequency conversion bridge arm (301d) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the input terminal is connected to the second end of the secondary side of the transformer (20) through the second filter capacitor (302*).

[0011] Preferably, the first path terminals of the two switching elements (30111c, 30111d) of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are interconnected.

[0012] Preferably, the ground terminal of the voltage regulator module (30116) is connected to the first path terminal of the switch (30111).

[0013] Preferably, the rectifier circuit (10) is a full-bridge rectifier circuit.

[0014] Preferably, the bidirectional inverter further includes a controller, which is electrically connected to the rectifier circuit (10) and the frequency conversion circuit (30) for outputting an inverter control signal or a rectifier controller signal to the rectifier circuit (10) and for outputting a frequency conversion signal to the frequency conversion circuit (30) so as to control the switching element (30111) to be turned on or off by controlling the switching element driver (3012) of the frequency conversion circuit (30).

[0015] This application also provides a photovoltaic inverter system, which includes the bidirectional inverter of the above claim.

[0016] The bidirectional inverter and photovoltaic inverter system provided in this application are based on the bidirectional inverter provided in this application. The bidirectional inverter includes a rectifier circuit, a transformer, and a frequency conversion circuit. The rectifier circuit is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer, or to rectify the AC signal output from the primary side of the transformer into an external DC signal and output it. The frequency conversion circuit is used to adjust the frequency of the AC signal output from the secondary side of the transformer, or to adjust the frequency of the received AC signal. By setting a switch, a first diode, a second diode, a first voltage divider capacitor, a second voltage divider capacitor, and a voltage regulator module on the frequency conversion bridge arm, the received AC signal is partially converted into a stable voltage, and the obtained stable voltage is used to power the switch driver, eliminating the need for an auxiliary power supply and reducing the hardware cost of the bidirectional inverter. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0018] Figure 1 The connection relationship of the frequency conversion circuit of a bidirectional inverter according to an embodiment of this application. Figure 1 .

[0019] Figure 2 This is a schematic diagram of the circuit connection relationship of the frequency conversion bridge arm according to an embodiment of this application.

[0020] Figure 3 This is a schematic diagram showing the connection relationship of the frequency conversion bridge arm in the bidirectional inverter of the first embodiment of this application.

[0021] Figure 4 This is a simulation diagram of the voltage waveform at the output terminal of the voltage regulator according to the first embodiment of this application.

[0022] Figure 5 This is a schematic diagram showing the connection relationship of the leakage protection diodes in the bidirectional inverter in the first embodiment of this application.

[0023] Figure 6 This is a schematic diagram showing the connection relationship of the frequency conversion bridge arm in the bidirectional inverter of the second embodiment of this application.

[0024] Figure 7 This is a simulation diagram of the voltage waveform at the output terminal of the voltage regulator according to the second embodiment of this application.

[0025] Figure 8 The connection relationship of the frequency conversion circuit of a bidirectional inverter according to an embodiment of this application. Figure 2 .

[0026] The realization of the objectives, functional features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0027] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0028] Various embodiments of the present application will now be described with reference to the accompanying drawings. In the following description, suffixes such as “module,” “part,” or “unit” used to denote elements are used only for the convenience of the description and have no specific meaning in themselves.

[0029] The main purpose of this application is to propose a bidirectional inverter and a photovoltaic inverter system. Please refer to [reference needed]. Figure 1 , Figure 1 The connection relationship of a bidirectional inverter according to an embodiment of this application. Figure 1The bidirectional inverter includes a rectifier circuit (10), a transformer (20), and a frequency conversion circuit (30). The rectifier circuit (10) is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer (20), or to rectify the AC signal output from the primary side of the transformer (20) into an external DC signal and output it. The frequency conversion circuit (30) is used to adjust the frequency of the AC signal output from the secondary side of the transformer (20), or to adjust the frequency of the received AC signal. The frequency conversion circuit (30) includes a first frequency conversion bridge arm (301a) and a second frequency conversion bridge arm (301b) with the same structure. The input terminal of the first frequency conversion bridge arm (301a) is connected to the output terminal of the second frequency conversion bridge arm (301b) and the first end of the secondary side. The output terminal of the first frequency conversion bridge arm (301a) is connected to the input terminal of the second frequency conversion bridge arm (301b) and the second end of the secondary side.

[0030] Further, please refer to Figure 2 , Figure 2 This is a schematic diagram of the circuit connection relationship of a frequency conversion bridge arm according to an embodiment of this application. The first frequency conversion bridge arm (301a) includes a bridge arm circuit (3011a) and a switching driver (3012a). The bridge arm circuit (3011a) includes: a switching element (30111a), a first diode (30112), a second diode (30113), a first voltage divider capacitor (30114), a second voltage divider capacitor (30115), and a voltage regulator module (30116). One end of the first voltage divider capacitor (30114) serves as the input terminal of the first frequency conversion bridge arm (301a), and the other end of the first voltage divider capacitor (30114) is connected to the anode of the first diode (30112). The cathode of the first diode (30112) is connected to the cathode of the second diode (30113). The anode of the second diode (30113) is connected to the cathode of the second diode (30113) via the second voltage divider capacitor (3015). The second terminal of the switch (30111a) serves as the output terminal of the first frequency conversion bridge arm (301a). The input terminal of the voltage regulator module (30116) is connected to the anode of the second diode (30113), and the output terminal of the voltage regulator module (30116) is connected to the cathode of the second diode (30113). The output terminal of the voltage regulator module (30116) is also connected to the power supply terminal of the switch driver (3012a), and the drive output terminal of the switch driver (3012a) is connected to the control terminal of the switch (30111a).

[0031] Please refer to Figure 3 , Figure 3This is a schematic diagram of the connection relationship of the frequency conversion bridge arms in the bidirectional inverter of the first embodiment of this application. In the first embodiment, the frequency conversion circuit (30) further includes a first filter capacitor (302); the input terminal of the bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the output terminal is connected to the second end of the secondary side of the transformer (20) through the first filter capacitor (302); the output terminal of the bridge arm circuit (3011b) of the second frequency conversion bridge arm (301b) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the input terminal is connected to the second end of the secondary side of the transformer (20) through the first filter capacitor (302).

[0032] Furthermore, when the switching element (30111a) of the first frequency conversion bridge arm (301a) is turned on, and the AC voltage signal can forward conduct the first diode (30112) and the second diode (30113), the AC voltage signal synchronously charges the first voltage divider capacitor (30114a), the second voltage divider capacitor (3015a) and the first filter capacitor (302), and the voltage required by the voltage divider gradient adapter switch driver (3012a) is formed by the first voltage divider capacitor (30114a), the second voltage divider capacitor (3015a) and the first filter capacitor (302). The voltage is further stabilized by the output of the voltage stabilization module (3016a), so that part of the power of the AC signal can power the switch driver (3012a), saving the hardware cost of an auxiliary source. Similarly, the second frequency conversion bridge arm (302b) can also use part of the AC signal power to power the switching driver (3012b), saving the hardware cost of an auxiliary source.

[0033] Please refer to Figure 4 , Figure 4 This is a simulation diagram of the voltage waveform at the output terminal of the voltage regulator according to the first embodiment of this application. In the figure, the horizontal axis represents the time after the switching device (30111a) or switching device (30111b) is turned on, and the vertical axis represents the voltage amplitude at the output terminal of the voltage regulator module (3016a) or voltage regulator module (3016b). As can be seen from the figure, after the switching device (30111a) or switching device (30111b) is turned on, the voltage at the output terminal of the voltage regulator module (3016a) or voltage regulator module (3016b) quickly changes to 12V and remains stable, which can ensure the stable power supply of the switching device driver (3012a) and the switching device driver (3012b) and has the ability to replace the auxiliary power source.

[0034] Please refer to Figure 5 , Figure 5This is a schematic diagram showing the connection relationship of the anti-leakage diode in the bidirectional inverter in the first embodiment of this application. In one embodiment, the bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) further includes at least one anti-leakage diode (30117a). The anode of the anti-leakage diode (30117a) is connected to the first path terminal of the switch (30111a), and the cathode of the anti-leakage diode (30117a) is connected to the input terminal of the bridge arm circuit (3011a). Through the unidirectional conduction characteristic of the diode, leakage current is prevented when the selection of the switch (30111a) is not fully synchronized with the AC voltage signal. Similarly, the bridge arm circuit (3011b) of the second frequency conversion bridge arm (301b) is also correspondingly provided with an anti-leakage diode (30117b), which can also prevent leakage current of the switch (30111b).

[0035] Please refer to Figure 6 and Figure 7 , Figure 6 This is a schematic diagram showing the connection relationship of the frequency conversion bridge arms in the bidirectional inverter of the second embodiment of this application. Figure 7 This is a simulation diagram of the voltage waveform at the output terminal of the voltage regulator according to the second embodiment of this application. In one embodiment, the first path terminals of the switching elements (30111a, 30111b) of the first frequency conversion bridge arm (301a) and the second frequency conversion bridge arm (301b) are interconnected. Figure 7 In the graph, the horizontal axis represents the time after the switching device (30111a) or switching device (30111b) is turned on, and the vertical axis represents the voltage amplitude at the output terminal of the voltage regulator module (3016a) or voltage regulator module (3016b). Figure 7 As can be seen, the second embodiment can also achieve the above-mentioned effect that after the switching element (30111a) or switching element (30111b) is turned on, the voltage at the output terminal of the voltage regulator module (3016a) or voltage regulator module (3016b) quickly changes to 12V and remains stable, which can ensure the stable power supply of the switching element driver (3012a) and the switching element driver (3012b) and has the ability to replace the auxiliary source.

[0036] Please refer to Figure 8 , Figure 8 The connection relationship of the frequency conversion circuit of a bidirectional inverter according to an embodiment of this application. Figure 2 In one embodiment, the bidirectional inverter further includes a third frequency conversion bridge arm (301c), a fourth frequency conversion bridge arm (301d), and a second filter capacitor (302*); wherein the internal structure of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) is the same as that of the first frequency conversion bridge arm (301a); Furthermore, the input terminal of the bridge arm circuit (3011c) of the third frequency conversion bridge arm (301c) is connected to the first terminal of the secondary side of the transformer (20), and the output terminal is connected to the second terminal of the secondary side of the transformer (20) through the second filter capacitor (302*); the output terminal of the bridge arm circuit (3011d) of the fourth frequency conversion bridge arm (301d) in the frequency conversion circuit (30) is connected to the first terminal of the secondary side of the transformer (20), and the input terminal is connected to the second terminal of the secondary side of the transformer (20) through the second filter capacitor (302*). The third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are similar to the first conversion bridge arm (301a) and the second conversion bridge arm (301b) mentioned above, and also have the ability to eliminate the auxiliary source. In one embodiment, the first path terminals of the two switching elements (30111c, 30111d) of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are interconnected. Furthermore, the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are both subject to the connection relationship between the first conversion bridge arm (301a) and the second conversion bridge arm (301b) in the first and second embodiments described above.

[0037] In other embodiments, the first conversion bridge arm (301a) and the second conversion bridge arm (301b) can each be selected from any one of the connection relationships in the first embodiment and the second embodiment described above, and the first embodiment and the second embodiment can coexist and be combined.

[0038] In one embodiment, the voltage regulator module (30116) preferably uses a three-terminal voltage regulator chip. The ground terminal of the voltage regulator module (30116) is connected to the first path terminal of the switch (30111), and an anti-reverse diode can be provided on the wiring. The anode of the anti-reverse diode faces the ground terminal of the voltage regulator module (30116), and the cathode of the anti-reverse diode faces the first path terminal of the switch (30111).

[0039] In one embodiment, the rectifier circuit (10) is a full-bridge rectifier circuit.

[0040] In one embodiment, the bidirectional inverter further includes a controller electrically connected to the rectifier circuit (10) and the frequency conversion circuit (30), for outputting an inverter control signal or a rectifier controller signal to the rectifier circuit (10), and for outputting a frequency conversion signal to the frequency conversion circuit (30), so as to control the switching element (30111) to be turned on or off by controlling the switching element driver (3012) of the frequency conversion circuit (30), thereby realizing bidirectional frequency conversion of the AC signal.

[0041] The province also provides a photovoltaic inverter system, which includes the bidirectional inverter of the above-mentioned claim. The photovoltaic power generation equipment can be connected to the bidirectional inverter as a DC power source. The AC load terminal of the frequency conversion circuit (30) of the bidirectional inverter is connected to the power grid. The bidirectional inverter converts the DC signal from the photovoltaic power generation equipment into an initial AC signal through the rectifier circuit (10). The initial AC signal is transformed by the transformer (20) to obtain a transformed AC signal. The transformed AC signal is frequency-converted by the frequency conversion circuit (30) to adapt to the power grid frequency and then input to the power grid to realize grid-connected power generation.

[0042] The bidirectional inverter and photovoltaic inverter system provided in this application are based on the bidirectional inverter provided in this application. The bidirectional inverter includes a rectifier circuit (10), a transformer (20), and a frequency conversion circuit (30). The rectifier circuit (10) is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer (20), or to rectify the AC signal output from the primary side of the transformer (20) into an external DC signal and output it. The frequency conversion circuit (30) is used to adjust the frequency of the AC signal output from the secondary side of the transformer (20), or to adjust the frequency of the received AC signal. By setting a voltage regulator module (30116) on the frequency conversion bridge arm (301a~d), the received AC signal is partially converted into a stable voltage, and the obtained stable voltage is used to power the switching device driver (3012), eliminating the need for an auxiliary power supply and reducing the hardware cost of the bidirectional inverter.

[0043] It is understood that the above scenarios are merely examples and do not constitute a limitation on the application scenarios of the technical solutions provided in the embodiments of this application. The technical solutions of this application can also be applied to other scenarios. For example, as those skilled in the art will know, with the evolution of device architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0044] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0045] The steps in the method of this application embodiment can be adjusted, combined, or deleted according to actual needs.

[0046] The units in the device of this application embodiment can be merged, divided, and deleted according to actual needs.

[0047] In this application, the same or similar terms, concepts, technical solutions and / or application scenario descriptions are generally described in detail only when they appear for the first time. When they appear again, they are generally not repeated for the sake of brevity. When understanding the technical solutions and other contents of this application, the same or similar terms, concepts, technical solutions and / or application scenario descriptions that are not described in detail later can be referred to their previous relevant detailed descriptions.

[0048] In this application, the descriptions of the various embodiments have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0049] The technical features of the present application can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present application.

[0050] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A bidirectional inverter, characterized in that, The bidirectional inverter includes a rectifier circuit (10), a transformer (20), and a frequency conversion circuit (30); The rectifier circuit (10) is used to invert the received DC signal into an AC signal and output it to the primary side of the transformer (20), or to rectify the AC signal output from the primary side of the transformer (20) into an external DC signal and output it. The frequency conversion circuit (30) is used to adjust the frequency of the AC signal output from the secondary side of the transformer (20), or to adjust the frequency of the received AC signal. The frequency conversion circuit (30) includes a first frequency conversion bridge arm (301a) and a second frequency conversion bridge arm (301b) with the same structure. The input terminal of the first frequency conversion bridge arm (301a) is connected to the output terminal of the second frequency conversion bridge arm (301b) and the first end of the secondary side. The output terminal of the first frequency conversion bridge arm (301a) is connected to the input terminal of the second frequency conversion bridge arm (301b) and the second end of the secondary side. The first frequency conversion bridge arm (301a) includes a bridge arm circuit (3011a) and a switching driver (3012a). The bridge arm circuit (3011a) includes a switching element (30111a), a first diode (30112), a second diode (30113), a first voltage divider capacitor (30114), a second voltage divider capacitor (30115), and a voltage regulator module (30116). One end of the first voltage divider capacitor (30114) serves as the input terminal of the first frequency conversion bridge arm (301a), and the other end of the first voltage divider capacitor (30114) is connected to the anode of the first diode (30112). The cathode of the first diode (30112) is connected to the anode of the second diode (30113). The cathode of the second diode (30113) is connected to the first path terminal of the switching element (30111a) through the second voltage dividing capacitor (30115). The second path terminal of the switching element (30111a) serves as the output terminal of the first frequency conversion bridge arm (301a). The input terminal of the voltage regulator module (30116) is connected to the anode of the second diode (30113). The output terminal of the voltage regulator module (30116) is connected to the cathode of the second diode (30113). The output terminal of the voltage regulator module (30116) is also connected to the power supply terminal of the switching element driver (3012a). The drive output terminal of the switching element driver (3012a) is connected to the control terminal of the switching element (30111a).

2. The bidirectional inverter according to claim 1, characterized in that, The frequency conversion circuit (30) also includes a first filter capacitor (302); The input terminal of the bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the output terminal is connected to the second end of the secondary side of the transformer (20) through the first filter capacitor (302). The output terminal of the bridge arm circuit (3011b) of the second frequency conversion bridge arm (301b) in the frequency conversion circuit (30) is connected to the first terminal of the secondary side of the transformer (20), and the input terminal is connected to the second terminal of the secondary side of the transformer (20) through the first filter capacitor (302).

3. The bidirectional inverter according to claim 2, characterized in that, The first frequency conversion bridge arm (301a) and the first path terminals of the switching elements (30111a, 30111b) of the second frequency conversion bridge arm (301b) are interconnected.

4. The bidirectional inverter according to claim 1, characterized in that, The bridge arm circuit (3011a) of the first frequency conversion bridge arm (301a) further includes at least one leakage protection diode (30117a), the anode of the leakage protection diode (30117a) is connected to the first path terminal of the switching element (30111a), and the cathode of the leakage protection diode (30117a) is connected to the input terminal of the bridge arm circuit (3011a).

5. The bidirectional inverter according to claim 2, characterized in that, The bidirectional inverter also includes a third frequency conversion bridge arm (301c), a fourth frequency conversion bridge arm (301d), and a second filter capacitor (302*). The internal structures of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are the same as those of the first frequency conversion bridge arm (301a). Furthermore, the input terminal of the bridge arm circuit (3011c) of the third frequency conversion bridge arm (301c) is connected to the first end of the secondary side of the transformer (20), and the output terminal is connected to the second end of the secondary side of the transformer (20) through the second filter capacitor (302*); the output terminal of the bridge arm circuit (3011d) of the fourth frequency conversion bridge arm (301d) in the frequency conversion circuit (30) is connected to the first end of the secondary side of the transformer (20), and the input terminal is connected to the second end of the secondary side of the transformer (20) through the second filter capacitor (302*).

6. The bidirectional inverter according to claim 5, characterized in that, The first path terminals of the two switching elements (30111c, 30111d) of the third frequency conversion bridge arm (301c) and the fourth frequency conversion bridge arm (301d) are interconnected.

7. The bidirectional inverter according to claim 1, characterized in that, The ground terminal of the voltage regulator module (30116) is connected to the first path terminal of the switch (30111).

8. The bidirectional inverter according to claim 1, characterized in that, The rectifier circuit is a full-bridge rectifier circuit.

9. The bidirectional inverter according to claim 1, characterized in that, The bidirectional inverter also includes a controller, which is electrically connected to the rectifier circuit (10) and the frequency conversion circuit (30). The controller is used to output an inverter control signal or a rectifier controller signal to the rectifier circuit (10) and to output a frequency conversion signal to the frequency conversion circuit (30) so as to control the switching element (30111) to be turned on or off by controlling the switching element driver (3012) of the frequency conversion circuit (30).

10. A photovoltaic inverter system, characterized in that, The photovoltaic inverter system includes the bidirectional inverter as described in any one of claims 1-9.

Images