Mode switching inverter and inverter system

Abstract

The utility model relates to a mode-switching inverter and an inverter system. The inverter comprises a control circuit, a coupling detection unit and an AC interface. The inverter is connected with a power grid through an alternating current interface; the signal input end of a control circuit used for detecting and judging the output electrical characteristics of the coupling detection unit is connected with the coupling detection unit. Compared with the prior art, the utility model has the advantages that simple hardware is added to realize the switching of the inverter between an off-grid operation mode and a grid-connected operation mode, a grid-connected port and an off-grid port are multiplexed, and the inverter is prevented from mistakenly entering the off-grid mode under the condition of being connected with a power grid.

Description

Technical Field

[0001] The utility model relates to the technical field of inverters, in particular to an inverter with a switching mode and an inverter system. Background Art

[0002] In order to meet the regulatory requirements of islanding protection, existing grid-connected inverters stop working after the grid power is cut off and cannot continue to output AC voltage. However, in remote areas, there is a need for inverters to operate off-grid. Currently, there are the following several off-grid operation schemes for inverters:

[0003] One existing scheme is to add an off-grid port to the output end of the inverter. After detecting that the mains power is disconnected, the output relay and the grid-connected port are disconnected, and the off-grid port is connected, as Figure 1 and Figure 2 shown;

[0004] Another existing scheme is that the inverter does not add an off-grid port, and an on-grid / off-grid switching control box is added outside the inverter. The on-grid / off-grid switching control circuit therein is as Figure 3 shown.

[0005] In order to realize the off-grid operation function of the grid-connected inverter, the existing schemes all need to add hardware devices. The first existing scheme needs to add an off-grid port and an internal switching relay to the inverter body, and the second existing scheme needs to add an on-grid / off-grid switching box outside the inverter.

[0006] How to realize an inverter with simple hardware automatic mode switching has become a technical problem to be solved. Summary of the Utility Model

[0007] The purpose of the utility model is to provide an inverter with a switching mode and an inverter system to overcome the defects of the above-mentioned existing technologies.

[0008] The purpose of the utility model can be realized by the following technical solutions:

[0009] According to one aspect of the utility model, an inverter with a switching mode is provided. The inverter includes a control circuit, a coupling detection unit, and an AC interface; the inverter is connected to the grid through the AC interface;

[0010] The signal input end of the control circuit (110) for detecting and discriminating the electrical characteristics output by the coupling detection unit is connected to the coupling detection unit.

[0011] Preferably, the coupling detection unit includes a first signal interface and a detection circuit connected to each other, and the detection circuit is connected to the control circuit.

[0012] More preferably, the coupling detection unit further includes a push switch installed outside the inverter, and the push switch is connected to the detection circuit through a first signal interface.

[0013] More preferably, the coupling detection unit further includes a magnetic sensor installed outside the inverter, and the magnetic sensor is connected to the detection circuit through a first signal interface.

[0014] More preferably, the AC interface includes an extension cable and an AC output terminal; the extension cable is connected to the detection circuit through a first signal interface, and the extension cable is connected to the AC output terminal.

[0015] More preferably, the AC output terminal includes an AC power interface and a second signal interface; the second signal interface includes at least two signal lines.

[0016] According to another aspect of the present invention, an inverter system is provided, which includes an inverter, an AC adapter, and a load;

[0017] The AC adapter includes a coupling trigger unit and a third signal interface connected to the AC interface of the inverter.

[0018] Preferably, the AC adapter further includes a first terminal, where the first terminal is connected to the AC interface of the inverter, and the first terminal is electrically coupled to the first signal interface of the inverter.

[0019] More preferably, the coupling trigger unit includes a magnetic device disposed inside the first terminal, which is matched with the magnetic sensor of the coupling detection unit.

[0020] More preferably, the coupling trigger unit further includes a resistive impedance network, and the resistive impedance network is disposed in the first terminal or the second terminal.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) Under the condition of adding simple hardware, the present invention realizes the function of the inverter to operate off-grid with load through various methods such as structural change, magnetic field transformation, and impedance network, and realizes the switching between the off-grid operation mode and the grid-connected operation mode of the inverter through the control unit hardware, while avoiding the disadvantage of unstable software control.

[0023] 2) Through the connection between the AC adapter and the AC output port of the inverter, the present invention multiplexes the grid-connected port and the off-grid port. At the same time, the AC adapter and the grid-connected mode are mutually exclusive, preventing the device from entering the off-grid mode incorrectly when connected to the grid, resulting in equipment damage.

[0024] 3) The DC interface of the inverter of the present utility model is connected to the battery pack, which can charge when the grid load is low and release electrical energy when the grid load increases, thereby reducing the energy waste of the power system and improving the efficiency of the entire power system. Description of the Drawings

[0025] Figure 1 Fig. is a schematic circuit diagram of the grid-connected operation mode of the inverter in the prior art;

[0026] Figure 2 Fig. is a schematic circuit diagram of the inverter connected to the off-grid port in the prior art;

[0027] Figure 3 Fig. is a schematic circuit diagram of adding a grid-connected and off-grid switching control box outside the inverter in the prior art;

[0028] Figure 4 Fig. is a schematic structural diagram of the inverter system in the present utility model;

[0029] Figure 5 Fig. is a schematic structural diagram of the inverter with a battery pack in the present utility model;

[0030] Figure 6 Fig. is a schematic structural diagram of the AC output terminal of the inverter in the present utility model;

[0031] Figure 7 Fig. is a schematic structural diagram of the system electrically coupled by pressing the switch in the off-grid operation mode of the present utility model;

[0032] Figure 8 Fig. is the electrical signal sampling circuit of the first signal interface in the present utility model;

[0033] Figure 9 Fig. is a schematic structural diagram of the system electrically coupled by a magnetic sensor in the off-grid operation mode of the present utility model;

[0034] Figure 10 Fig. is a schematic structural diagram of the system electrically coupled by the first signal interface in the off-grid operation mode of the present utility model;

[0035] Figure 11 Fig. is a schematic structural diagram of the grid-connected operation mode of the present utility model;

[0036] In the drawings, 101 is the inverter, 102 is the DC interface, 110 is the control circuit, 120 is the detection circuit, 121 is the first signal interface, 122 is the push switch, 123 is the magnetic sensor, 130 is the AC interface, 131 is the extension cable, 132 is the AC output terminal, 133 is the second signal interface, 140 is the battery pack, 201 is the AC adapter, 202 is the first terminal, 203 is the second terminal, 204 is the magnetic device, 210 is the impedance network, and 301 is the load. Detailed implementation mode

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] The present invention relates to an inverter system with a switching mode, such as Figure 4 , the system includes an inverter 101, an AC adapter 201, and a power grid or load 301 connected in sequence; the inverter 101 includes a control circuit 110, a coupling detection unit, a first signal interface 121, an AC interface 130, and at least one DC interface 102.

[0040] The coupling detection unit is electrically coupled to the control circuit 110 of the inverter 101. The coupling detection unit includes a first signal interface 121 and a detection circuit 120 connected to each other, and the detection circuit 120 is connected to the control circuit 110.

[0041] The first signal interface 121 is electrically coupled to the control circuit 110 of the inverter 101 through the detection circuit 120.

[0042] The control circuit 110 is used to detect and distinguish the electrical characteristics output by the coupling detection unit, and its signal input terminals are respectively connected to a threshold signal source and the detection circuit 120.

[0043] The control circuit 110 includes a comparator. The positive input terminal of the comparator is connected to the threshold signal source, and the negative input terminal is connected to the detection circuit 120.

[0044] When the voltage of the threshold signal source is greater than the sampling signal voltage, the comparator outputs a high level, and the control circuit 110 sets the inverter 101 to operate in the off-grid mode; otherwise, the control circuit 110 sets the inverter 101 to operate in the grid-connected mode.

[0045] In the off-grid mode, the inverter 101 supplies power to the load through the AC adapter 201; in the grid-connected mode, the inverter 101 is directly connected to the power grid.

[0046] The AC adapter 201 includes at least two types of terminals, a first terminal 202 and a second terminal 203, where the first terminal 202 is connected to the AC interface 130 of the inverter 101, and after connection, it can change the impedance characteristics of the first signal interface 121, and at least one second terminal 203 is connected to the load 301.

[0047] Off-grid operation state: When the DC input of the inverter 101 is normal, even if the AC interface 130 does not detect a connection to the power grid, it can start and output an AC voltage to supply power to the load 301.

[0048] Grid-connected operation state: When the DC input of the inverter 101 is normal, it can only grid-connected and output power when the AC interface 130 detects eligible electrical signal parameters, where the conditions include AC voltage, AC frequency, etc.

[0049] Such as Figure 4 , the AC interface 130 includes an extension cable 131 and an AC output terminal 132.

[0050] Such as Figure 5 As shown, the DC interface 102 of the inverter 101 is connected to the battery pack 140, and the battery pack 140 and the inverter 101 are combined into one structure, such as an integrated energy storage unit. It can charge the battery to store electrical energy when the grid load is low and release electrical energy when the load increases, thereby reducing energy waste in the power system and improving the efficiency of the entire power system.

[0051] Such as Figure 6 , the AC output terminal 132 includes an AC power interface and a second signal interface 133. The second signal interface 133 includes at least two signal lines, and the impedance characteristics between the signal lines are changed through an externally connected impedance network. The control circuit 110 sampling circuit of the inverter 101 detects the impedance characteristics between the signal wires; the impedance network includes a resistor network, an inductor network, a capacitor network, a hybrid network composed of resistors, capacitors and inductors, or a magnetic device network, etc.

[0052] The AC adapter 201 internally includes an impedance network 210, and the first terminal 202 is electrically coupled to the first signal interface 121 of the inverter 101.

[0053] All the preset conditions mentioned below are: the voltage of the threshold signal source is greater than the voltage value of the first signal interface 121, and the voltage of the threshold signal source is set to 1V.

[0054] Embodiment 2

[0055] The present invention also relates to a scenario one of the off-grid operation mode of an inverter system.

[0056] Such as Figure 7 As shown, the first terminal 202 is not electrically coupled to the first signal interface 121 of the inverter 101. After the first terminal 202 is connected to the AC interface 130 of the inverter 101, the impedance characteristics of the first signal interface 121 are changed through the structural characteristics.

[0057] The coupling detection unit further includes a push switch 122 installed outside the inverter 101.

[0058] The first signal interface 121 of the inverter 101 is electrically coupled to a push switch 122 outside the inverter. When the first terminal 202 is connected and the AC interface 130 of the inverter 101 is connected, the input characteristics of the push switch 122 are changed, and then the electrical signal characteristics of the first signal interface 121 are changed, so that the electrical signal characteristics of the first signal interface 121 meet the preset conditions, and the control circuit 110 controls the inverter 101 to operate in the off-grid mode.

[0059] As Figure 8 shown, the detection circuit 120 includes a voltage dividing network composed of resistors R1 and R2. The signal line of the first signal interface 121 is connected to both ends of the resistor R2, and the control circuit 110 samples the voltage between the resistors R1 and R2 through a sampling port. The detection circuit 120 includes an isolation optocoupler, and the control circuit 110 samples the electrical characteristic value of the first signal interface 121 through the isolation optocoupler.

[0060] The present invention also relates to a second scenario of the off-grid operation mode of an inverter system.

[0061] As Figure 9 shown, the first terminal 202 is not electrically coupled to the first signal interface 121 of the inverter 101. After the first terminal 202 is connected to the AC interface 130 of the inverter 101, the impedance characteristic of the first signal interface 121 is changed through the transformation of the magnetic field characteristic.

[0062] The coupling detection unit further includes a magnetic sensor 123 installed outside the inverter 101. The first signal interface 121 of the inverter 101 is electrically coupled to the magnetic sensor 123 outside the inverter. The first terminal 202 contains a magnetic device 204 inside, such as a permanent magnet. When the first terminal 202 is connected to the AC interface 130 of the inverter 101, the magnetic field around the magnetic sensor 123 is changed, and then the output characteristic of the magnetic sensor 123 is changed, and then the electrical signal characteristic of the first signal interface 121 is changed, so that the electrical signal characteristic of the first signal interface 121 meets the preset conditions, and the control circuit 110 controls the inverter 101 to operate in the off-grid mode.

[0063] The first terminal 202 and the second terminal 203 are structurally combined into one unit.

[0064] Embodiment 3

[0065] The present invention also relates to a third scenario of the off-grid operation mode of an inverter system.

[0066] As Figure 10 shown, the AC adapter 201 is electrically coupled to the first signal interface 121 of the inverter 101, and the first signal interface 121 includes two signal wires.

[0067] The coupling trigger unit further includes an impedance network 210. The impedance network 210 is disposed in the first terminal 202 or the second terminal 203. The first terminal 202 is connected to the AC interface 130 of the inverter 101. After the connection, the impedance characteristic of the first signal interface 121 is changed by the access of the impedance network 210, and then the electrical signal characteristic of the first signal interface 121 is changed, so that the electrical signal characteristic of the first signal interface 121 meets the preset conditions, and the control circuit 110 controls the inverter 101 to operate in the off-grid operation mode.

[0068] Embodiment 4

[0069] The present invention also relates to a grid-connected operation mode scenario of an inverter system with a switching mode.

[0070] As Figure 11 shown, when the inverter 101 is not connected to the AC connector 201, the first signal interface 121 of the inverter 101 is not connected to the impedance network 210, and the impedance characteristic of the first signal interface 121 does not meet the preset conditions. The control circuit 110 controls the inverter to operate in the grid-connected operation mode.

[0071] The second terminal 203 of the AC adapter is a female connector and cannot be directly connected to the power grid.

[0072] The second terminal 203 of the AC adapter 201 cannot be connected to the inverter 101 to prevent reverse insertion.

[0073] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A switching mode inverter, characterized in that: The inverter (101) comprises a control circuit (110), a coupling detection unit and an AC interface (130); the inverter (101) is connected to a power grid via the AC interface (130); A signal input end of a control circuit (110) for detecting and determining the output electrical characteristics of the coupling detection unit is connected to the coupling detection unit; The coupling detection unit comprises a first signal interface (121) and a detection circuit (120) connected to each other, and the detection circuit (120) is connected to the control circuit (110); The coupling detection unit further comprises a magnetic sensor (123) installed outside the inverter (101), and the magnetic sensor (123) is connected to the detection circuit (120) via a first signal interface (121).

2. A switching mode inverter according to claim 1, characterized in that: The coupling detection unit further comprises a push switch (122) installed outside the inverter (101), and the push switch (122) is connected to the detection circuit (120) via a first signal interface (121).

3. The switching mode inverter according to claim 1, characterized in that: The AC interface (130) comprises an extension cable (131) and an AC output terminal (132); the extension cable (131) is connected to the detection circuit (120) via a first signal interface (121), and the extension cable (131) is connected to the AC output terminal (132).

4. A switching mode inverter according to claim 3, characterized in that: The AC output terminal (132) comprises an AC power interface and a second signal interface (133); the second signal interface (133) comprises at least two signal lines.

5. An inverter system, characterized in that: The system comprises an inverter (101), an AC adapter (201) and a load (301) according to any one of claims 1 to 4; The AC adapter (201) comprises a coupling trigger unit and a third signal interface connected to the AC interface (130) of the inverter (101).

6. The inverter system according to claim 5, characterized in that: The AC adapter (201) further comprises a first terminal (202), wherein the first terminal (202) is connected to the AC interface (130) of the inverter (101), and the first terminal (202) is electrically coupled to the first signal interface (121) of the inverter (101).

7. The inverter system according to claim 6, characterized in that: The coupling trigger unit comprises a magnetic device (204) arranged inside the first terminal (202) and matched with the magnetic sensor (123) of the coupling detection unit.

8. The inverter system according to claim 6, characterized in that: The coupling trigger unit further comprises an electrical impedance network (210), wherein the electrical impedance network (210) is disposed in the first terminal (202) or the second terminal (203).

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