A wind-solar inverter, control method and new energy system

Abstract

The application discloses a wind-solar inverter, a control method and a new energy system. The wind-solar inverter comprises: an input end of a rectifier circuit is connected with an output end of a wind driven generator; an output end of the rectifier circuit is connected with an input end of an inverter circuit; an input end of a composite circuit is connected with a photovoltaic array, and an output end of the composite circuit is used for connecting the input end of the inverter circuit; the composite circuit comprises a photovoltaic maximum power tracking circuit and a wind power chopping brake circuit which are integrated together; when the wind-solar inverter works in a wind power generation mode, the composite circuit exits work or works in a chopping brake mode; when the wind-solar inverter works in a photovoltaic power generation mode or works in a wind-solar combined power generation mode, the composite circuit is used for tracking maximum power of the photovoltaic array. The scheme integrates the chopping brake of the wind power and the MPPT function of the photovoltaic together, and the circuit devices are multiplexed, so that the power density is improved, and the cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of new energy power generation technology, specifically to a wind-solar converter, control method, and new energy system. Background Technology

[0002] Currently, with the continuous development of the new energy industry, photovoltaic power generation and wind power generation can be jointly established as wind-solar hybrid power plants. Initially, the wind and photovoltaic systems in these plants were independent before the step-up transformer; that is, the wind and photovoltaic systems were coupled together on the AC side before being connected to the grid. To reduce costs, most plants now couple the wind and photovoltaic systems on the DC side, which saves on a separate photovoltaic inverter and grid-connected transformer.

[0003] However, in current DC-coupled wind and solar power systems, the power density is not high. Summary of the Invention

[0004] In view of this, embodiments of this application provide a wind-solar converter, a control method, and a new energy system, which can further improve power density and reduce costs.

[0005] This application provides a wind-solar converter, which includes: a rectifier circuit, an inverter circuit, and a composite circuit; the input terminal of the rectifier circuit is used to connect to the output terminal of the wind turbine generator; the output terminal of the rectifier circuit is connected to the input terminal of the inverter circuit.

[0006] The input terminal of the composite circuit is used to connect to the photovoltaic array, and the output terminal of the composite circuit is used to connect to the input terminal of the inverter circuit; the composite circuit includes a photovoltaic maximum power tracking circuit and a wind power chopper braking circuit integrated together.

[0007] When the wind-solar converter operates in wind power generation mode, the composite circuit is used to exit operation or operate in chopper braking mode; when the wind-solar converter operates in photovoltaic power generation mode or wind-solar combined power generation mode, the composite circuit is used to perform maximum power point tracking on the photovoltaic array.

[0008] Preferably, the composite circuit includes: a first switching branch, a second switching branch, a third switching branch, and a freewheeling branch;

[0009] The first terminal of the first switching branch is connected to the positive input terminal of the inverter circuit, the second terminal of the first switching branch is connected to the first terminal of the second switching branch, and the second terminal of the second switching branch is connected to the negative input terminal of the inverter circuit; the freewheeling branch is connected in parallel across the two terminals of the first switching branch.

[0010] The first end of the third switch branch is used to connect to the positive end of the photovoltaic array, and the second end of the third switch branch is connected to the first end of the second switch branch.

[0011] When the composite circuit operates in chopper braking mode, the third switch branch is open; when the composite circuit operates in photovoltaic power generation mode, the first switch branch is open, the third switch branch is on, and the second switch branch is used for power conversion; when the composite circuit operates in wind and solar combined power generation mode, the first switch branch is open, the third switch branch is on, and the second switch branch is used for power conversion.

[0012] Preferably, the first switching branch includes at least a first resistor and a first switching device connected in series.

[0013] Preferably, the second switching branch includes at least a second switching device.

[0014] Preferably, the third switching branch includes at least an inductor connected in series and a third switching device.

[0015] Preferably, the freewheeling branch includes at least a first diode;

[0016] The anode of the first diode is connected to the second terminal of the first switch branch, and the cathode of the first diode is connected to the first terminal of the first switch branch.

[0017] Preferably, the first switching device and the second switching device are integrated into a single switching module.

[0018] Preferably, when there are multiple photovoltaic arrays, the composite circuit includes multiple third switch branches; the multiple photovoltaic arrays and the multiple third switch branches correspond one-to-one.

[0019] Preferably, when the photovoltaic array includes multiple photovoltaic arrays, the wind-solar converter includes multiple composite circuits; the multiple photovoltaic arrays and the multiple composite circuits correspond one-to-one.

[0020] Preferably, the second and third switching devices are integrated into a single switching module.

[0021] This application also provides a control method for a wind-solar converter, which includes: a rectifier circuit, an inverter circuit, and a composite circuit; the input terminal of the rectifier circuit is used to connect to the output terminal of the wind turbine generator; the output terminal of the rectifier circuit is connected to the input terminal of the inverter circuit; the input terminal of the composite circuit is used to connect to the photovoltaic array, and the output terminal of the composite circuit is used to connect to the input terminal of the inverter circuit; the composite circuit includes an integrated photovoltaic maximum power tracking circuit and a wind power chopper braking circuit.

[0022] The method includes:

[0023] When the wind-solar converter is operating in wind power generation mode, the control composite circuit is either out of operation or in chopper braking mode.

[0024] When the wind-solar converter operates in photovoltaic power generation mode or wind-solar combined power generation mode, the control composite circuit performs maximum power tracking on the photovoltaic array.

[0025] Preferably, the composite circuit includes: a first switching branch, a second switching branch, a third switching branch, and a freewheeling branch; the first end of the first switching branch is connected to the positive input terminal of the inverter circuit, the second end of the first switching branch is connected to the first end of the second switching branch, and the second end of the second switching branch is connected to the negative input terminal of the inverter circuit; the freewheeling branch is connected in parallel across the two ends of the first switching branch; the first end of the third switching branch is used to connect to the positive terminal of the photovoltaic array, and the second end of the third switching branch is connected to the first end of the second switching branch;

[0026] When the wind-solar converter is operating in wind power generation mode, the third switch branch of the specific control is disconnected.

[0027] When the wind-solar converter is operating in photovoltaic power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

[0028] When the wind-solar converter operates in the combined wind and solar power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

[0029] Preferably, when the wind-solar converter enters the chopper braking mode, it specifically includes:

[0030] First, disconnect the third switch branch, then connect the first and second switch branches.

[0031] When the wind-solar converter exits the chopper braking mode, the specific steps include:

[0032] First, disconnect both the first and second switch branches, then connect the third switch branch.

[0033] This application also provides a new energy system, including the wind-solar converter described above, and further including: a wind turbine, a photovoltaic array, and a transformer;

[0034] The wind turbine is used to connect to the input terminal of the rectified current in the wind-solar converter;

[0035] Photovoltaic arrays are used to connect to the input terminals of the composite circuits in wind-solar converters;

[0036] The output terminal of the inverter circuit in the wind-solar converter is used to connect to the transformer.

[0037] Therefore, the embodiments of this application have the following beneficial effects:

[0038] The wind-solar converter provided in this application includes a rectifier circuit, an inverter circuit, and a composite circuit. This composite circuit integrates a photovoltaic maximum power point tracking (MPPT) circuit and a wind power chopper braking circuit, meaning it combines the functions of MPPT and chopper braking. During wind power generation, when the bus voltage is too high or the wind-solar converter malfunctions, chopper braking is required. The composite circuit can dissipate energy, preventing damage to the converter's components. When generating photovoltaic power or combining wind and solar power, the composite circuit can implement the MPPT function, performing maximum power point tracking on the photovoltaic array. Because the wind-solar converter provided in this application integrates the wind power chopper braking and photovoltaic MPPT functions, and reuses circuit components, it improves power density and reduces costs. Attached Figure Description

[0039] Figure 1 A diagram illustrating the architecture of a combined wind power generation system provided in this application embodiment;

[0040] Figure 2 A schematic diagram of a wind-solar converter provided in an embodiment of this application;

[0041] Figure 3 A schematic diagram of another wind-solar converter provided in the embodiments of this application;

[0042] Figure 4 A schematic diagram of a specific composite circuit provided in an embodiment of this application;

[0043] Figure 5 A schematic diagram of yet another composite circuit provided in an embodiment of this application;

[0044] Figure 6 A schematic diagram of another composite circuit provided in an embodiment of this application;

[0045] Figure 7 A schematic diagram of a wind-solar converter provided in an embodiment of this application;

[0046] Figure 8 A flowchart of a control method for a wind-solar converter provided in this application embodiment;

[0047] Figure 9 A schematic diagram of a new energy system provided in an embodiment of this application;

[0048] Figure 10 This is a schematic diagram of another new energy system provided in an embodiment of this application. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions provided in this application, specific application scenarios will be introduced below.

[0050] See Figure 1 This figure is an architecture diagram of a wind power combined generation system provided in an embodiment of this application.

[0051] The wind power integrated system includes a wind turbine, a photovoltaic array, and a wind-solar converter 1000. The wind turbine typically includes blades 10 and a generator M. Additionally, the integrated system includes a transformer T. The AC power output from the wind-solar converter 1000 is fed back to the AC grid G ​​through the transformer T. The wind turbine employs an AC-DC-AC topology. The photovoltaic array uses a DC-DC converter and a combined energy-dissipating circuit topology.

[0052] The wind-solar converter 1000 provided in this application differs from conventional wind-solar converters. The wind-solar converter 1000 includes a rectifier circuit AC / DC 100, an inverter circuit DC / AC 200, and a composite circuit 300.

[0053] The input terminal of the rectifier circuit AC / DC100 is connected to the output terminal of the generator M; the output terminal of the rectifier circuit AC / DC100 is connected to the input terminal of the inverter circuit DC / AC200.

[0054] The input terminal of the composite circuit 300 is used to connect to the photovoltaic array, and the output terminal of the composite circuit 300 is used to connect to the input terminal of the inverter circuit DC / AC200. The composite circuit 300 includes a photovoltaic maximum power tracking circuit and a wind power chopper braking circuit integrated together. It has a high degree of integration, which can improve power density and reduce cost. The wind power chopper braking circuit is also known as the Chopper circuit.

[0055] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0056] The specific implementation of the wind power converter provided in this application embodiment is described below with reference to the accompanying drawings.

[0057] See Figure 2 The figure is a schematic diagram of a wind-solar converter provided in an embodiment of this application.

[0058] The wind-solar converter provided in this embodiment includes: a rectifier circuit 100, an inverter circuit 200, and a composite circuit 300; the input terminal of the rectifier circuit 100 is used to connect to the output terminal of a wind turbine (hereinafter referred to as a wind turbine); the output terminal of the rectifier circuit 100 is connected to the input terminal of the inverter circuit 200.

[0059] The input terminal of the composite circuit 300 is used to connect to the photovoltaic array, and the output terminal of the composite circuit 300 is used to connect to the input terminal of the inverter circuit 200. The composite circuit 300 includes an integrated photovoltaic maximum power point tracking (MPPT) circuit and a wind power chopper braking circuit, meaning that the composite circuit 300 has the combined functions of MPPT and chopper braking, not just a single function. It should be understood that during wind power generation, when the bus voltage is too high or the wind-solar converter malfunctions, chopper braking is required to release energy to the ground, preventing damage to the components in the converter.

[0060] When the wind-solar converter operates in wind power generation mode, the composite circuit 300 is used to either exit operation or operate in chopper braking mode. When the wind-solar converter is operating normally in wind power generation mode, the power from the photovoltaic array is not output to the input of the inverter circuit; therefore, the composite circuit 300 can be disabled, and the output of the rectifier circuit 100 can be directly connected to the input of the inverter circuit 200. Only when the wind-solar converter is operating in wind power generation mode, but the DC bus voltage exceeds the preset voltage threshold, or there is an abnormality in the power grid or the wind-solar converter itself, will the composite circuit 300 operate in chopper braking mode, i.e., to de-energize and release the power transmitted from the wind turbine for protection.

[0061] When the wind-solar converter operates in photovoltaic power generation mode, the wind turbine does not output electrical energy. Therefore, the composite circuit 300 is only used for maximum power tracking of the photovoltaic array, converting the electrical energy output by the photovoltaic array and outputting it to the input terminal of the inverter circuit 200.

[0062] When the wind-solar converter operates in the combined wind and solar power generation mode, the composite circuit 300 is used to perform maximum power point tracking on the photovoltaic array, that is, to convert the electrical energy of the photovoltaic array and output it to the input terminal of the inverter circuit 200.

[0063] The wind-solar converter provided in this application includes a rectifier circuit, an inverter circuit, and a composite circuit. This composite circuit integrates a photovoltaic maximum power point tracking (MPPT) circuit and a wind power chopper braking circuit, meaning it combines the functions of MPPT and chopper braking. During wind power generation, when the bus voltage is too high or the wind-solar converter malfunctions, chopper braking is required. The composite circuit can dissipate energy, preventing damage to the converter's components. When generating photovoltaic power or combining wind and solar power, the composite circuit can implement the MPPT function, performing maximum power point tracking on the photovoltaic array. Because the wind-solar converter provided in this application integrates the wind power chopper braking and photovoltaic MPPT functions, and reuses circuit components, it improves power density and reduces costs.

[0064] The following section, with reference to the accompanying diagram, details a specific implementation of the composite circuit.

[0065] See Figure 3 The figure is a schematic diagram of another wind-solar converter provided in the embodiments of this application.

[0066] The composite circuit in the wind-solar converter provided in this embodiment includes: a first switch branch 301, a second switch branch 302, a third switch branch 303, and a freewheeling branch 304;

[0067] The output of the rectifier circuit AC / DC100 is connected to the input of the inverter circuit DC / AC200. This should be understood. Figure 3 The diagram is a simplified illustration. In practice, the output terminals of the AC / DC100 rectifier circuit also include positive and negative output terminals.

[0068] The first terminal of the first switch branch 301 is connected to the positive input terminal DC+ of the inverter circuit DC / AC200, the second terminal of the first switch branch 301 is connected to the first terminal of the second switch branch 302, and the second terminal of the second switch branch 302 is connected to the negative input terminal DC- of the inverter circuit DC / AC200; the freewheeling branch 304 is connected in parallel across the two terminals of the first switch branch 301.

[0069] The first end of the third switch branch 303 is used to connect to the positive end of the photovoltaic array, and the second end of the third switch branch 303 is connected to the first end of the second switch branch 302.

[0070] When the composite circuit operates in chopper braking mode, the third switch branch 303 is disconnected; specifically, it is possible to control one of the first switch branch 301 and the second switch branch 302 to be always on, while the other is in chopper state. For example, it is better if the first switch branch 301 is always on and the second switch branch 302 is in chopper state.

[0071] When the composite circuit operates in photovoltaic power generation mode, the first switch branch 301 is open, the third switch branch 303 is open, and the second switch branch 302 is used for power conversion.

[0072] When the composite circuit operates in the wind-solar combined power generation mode, the first switch branch 301 is open, the third switch branch 303 is closed, and the second switch branch 302 is used for power conversion.

[0073] When the wind-solar converter enters the chopper braking mode, the specific steps include:

[0074] First, control the third switch branch 303 to disconnect, then control the first switch branch 301 and the second switch branch 302 to conduct;

[0075] When the wind-solar converter exits the chopper braking mode, the specific steps include:

[0076] First, disconnect the first switch branch 301 and the second switch branch 302, then connect the third switch branch 303.

[0077] The composite circuit in the wind power converter provided in this application embodiment can be reused for photovoltaic power generation and wind power generation. For example, the second switch branch 302 can provide an energy dissipation path during chopper braking and can also perform power conversion during the MPPT of photovoltaic power generation. Since the composite circuit provided in this application embodiment organically combines chopper braking and maximum power pursuit, it has a high degree of integration, thereby improving power density and reducing the cost of wind power converter.

[0078] The following describes the specific circuit implementation of a composite circuit provided in this application, with reference to the accompanying drawings.

[0079] See Figure 4 The figure is a schematic diagram of a specific composite circuit provided in an embodiment of this application.

[0080] The positive terminal PV+ of the photovoltaic array is connected to the first terminal of the third switching branch, and the negative terminal PV- of the photovoltaic array is connected to the negative input terminal DC- of the inverter circuit. The first terminal of the first switching branch is connected to the positive input terminal DC+ of the inverter circuit. Additionally, a capacitor C, which is the DC bus capacitor, is connected between the positive and negative input terminals of the inverter circuit.

[0081] The composite circuit in the wind-solar converter provided in this embodiment includes at least a first resistor Rg and a first switching device connected in series in the first switching branch. For example, the first switching device is T1. It should be understood that in actual products, for operational needs, a single switching device can generally be implemented by connecting multiple switching transistors in parallel.

[0082] The second switching branch includes at least a second switching device. For example, the second switching device is T2.

[0083] The third switching branch includes at least an inductor connected in series and a third switching device. For example, the third switching device is T3.

[0084] When both the first switching device T1 and the second switching device T2 are turned on, the electrical energy output by the rectifier circuit can be released through the first resistor Rg, the first switching device T1 and the second switching device T2. Rg, as a purely resistive element, can consume electrical energy, thereby reducing the DC bus voltage, that is, the DC+ voltage can be reduced.

[0085] The embodiments of this application do not specifically limit the specific implementation of the first switching device T1, the second switching device T2, and the third switching device T3. For example, they can be MOSFET or IGBT semiconductor switching devices. The first switching device T1, the second switching device T2, and the third switching device T3 all include anti-parallel body diodes.

[0086] The freewheeling branch includes at least a first diode D1; the anode of the first diode D1 is connected to the second terminal of the first switching branch, and the cathode of the first diode D1 is connected to the first terminal of the first switching branch.

[0087] When the wind power converter operates in photovoltaic (PV) power generation mode or combined wind and solar power generation mode, the electrical energy output from the PV array can be converted by the composite circuit and then reach the input terminal of the inverter circuit through the freewheeling branch. Furthermore, because D1 has a reverse cutoff function, the current at the input terminal of the inverter circuit will not flow backwards into the composite circuit through D1. The electrical energy from the PV array is transferred to the input terminal of the inverter circuit through D1, which is more energy-efficient than transferring it through the first switching branch, because Rg consumes energy.

[0088] The embodiments of this application do not specifically limit the specific implementation of the first switching device T1, the second switching device T2, and the third switching device T3. For example, the first switching device T1 and the second switching device T2 can be integrated into a single switching module 300a, that is, a single chip includes two switching transistors. The third switching device T3 can be set independently.

[0089] In this embodiment, the second switching device T2 is a shared device for both the photovoltaic maximum power point tracking circuit and the wind power chopper braking circuit. During chopper braking, both T1 and T2 are turned on. During MPPT, T2 performs a switching action according to the power dispatch command, i.e., performs power conversion.

[0090] The embodiments of this application do not specifically limit the specific implementation form of the photovoltaic array. For example, when the photovoltaic array includes multiple photovoltaic arrays, it may also include a single photovoltaic array. The implementation method of the composite circuit corresponding to multiple photovoltaic arrays is described below.

[0091] See Figure 5 This figure is a schematic diagram of another composite circuit provided in an embodiment of this application.

[0092] When a photovoltaic array includes multiple photovoltaic arrays, for example, n photovoltaic arrays, where n is an integer greater than or equal to 2, and they are the first photovoltaic array PV1 to the nth photovoltaic array PVn, the composite circuit includes multiple third switch branches; the multiple photovoltaic arrays and the multiple third switch branches correspond one-to-one. When there are n photovoltaic arrays, there are also n third switch branches in the composite circuit.

[0093] like Figure 5 As shown, the positive terminal PV1+ of the first photovoltaic array is connected to the first terminal of the third switching branch, i.e., the first terminal of inductor L1, which is connected in series with the third switching device T31. The negative terminal PV1- of the first photovoltaic array is connected to the negative input terminal DC- of the inverter circuit.

[0094] Similarly, the positive terminal PVn+ of the nth photovoltaic array is connected to the first terminal of the third switching branch, that is, to the first terminal of the inductor Ln, which is connected in series with the third switching device T3n. The negative terminal PVn- of the nth photovoltaic array is connected to the negative input terminal DC- of the inverter circuit.

[0095] Figure 5 In the wind-solar converter shown, for multiple photovoltaic arrays, there are only multiple third switch branches, but there is still only one first switch branch and one second switch branch. That is, multiple photovoltaic arrays share the first switch branch and the second switch branch.

[0096] The following describes another implementation method, in which when there are multiple photovoltaic arrays, there are also multiple corresponding composite circuits. That is, each photovoltaic array corresponds to a composite circuit and they do not share any switching branches.

[0097] See Figure 6 This figure is a schematic diagram of another composite circuit provided in an embodiment of this application.

[0098] A photovoltaic array consists of multiple components. Continuing with an example of n photovoltaic arrays, a wind-solar converter consists of multiple composite circuits. The multiple photovoltaic arrays and multiple composite circuits correspond one-to-one, that is, one photovoltaic array corresponds to one composite circuit.

[0099] from Figure 6 It can be seen that, with Figure 5 The difference is that, in addition to each photovoltaic array having its own third switch branch, it also has its own first switch branch and second switch branch. That is, each photovoltaic array has its own composite circuit, which includes the first switch branch, the second switch branch and the third switch branch.

[0100] The positive terminal PV1+ of the first photovoltaic array is connected to the first terminal of the third switching branch, i.e., the first terminal of inductor L1. Inductor L1 is connected in series with the third switching device T31. The negative terminal PV1- of the first photovoltaic array is connected to the negative input terminal DC- of the inverter circuit.

[0101] Similarly, the positive terminal PVn+ of the nth photovoltaic array is connected to the first terminal of the third switching branch, that is, to the first terminal of the inductor Ln, which is connected in series with the third switching device T3n. The negative terminal PVn- of the nth photovoltaic array is connected to the negative input terminal DC- of the inverter circuit.

[0102] The first photovoltaic array corresponds to the first switch branch (T11 and Rg1 in series) and the second switch branch (T21) in the first composite circuit. The second photovoltaic array corresponds to the first switch branch (T1n and Rgn in series) and the second switch branch (T2n) in the nth composite circuit.

[0103] The above Figure 4 , Figure 5and Figure 6 In the composite circuit shown, both the first and second switching devices can be integrated into a single switching module. Another implementation method is described below, where the second and third switching devices are integrated into a single switching module.

[0104] See Figure 7 The figure is a schematic diagram of a wind-solar converter provided in an embodiment of this application.

[0105] Figure 7 The third switching device T3 and the second switching device T2 in the composite circuit shown can be integrated into a single switching module 300b, meaning that one chip includes two switching devices. In this case, the first switching device T1 can be set independently.

[0106] Based on the wind-solar converter provided in the above embodiments, this application also provides a control method for the wind-solar converter, which will be described in detail below with reference to the accompanying drawings.

[0107] Method Implementation Examples

[0108] See Figure 8 The figure is a flowchart of a control method for a wind-solar converter provided in an embodiment of this application.

[0109] The control method for a wind-solar converter provided in this embodiment includes a rectifier circuit, an inverter circuit, and a composite circuit. The input terminal of the rectifier circuit is used to connect to the output terminal of the wind turbine generator. The output terminal of the rectifier circuit is connected to the input terminal of the inverter circuit. The input terminal of the composite circuit is used to connect to the photovoltaic array, and the output terminal of the composite circuit is used to connect to the input terminal of the inverter circuit. The composite circuit includes an integrated photovoltaic maximum power tracking circuit and a wind power chopper braking circuit.

[0110] The method includes:

[0111] S801: When the wind-solar converter is operating in wind power generation mode, the control composite circuit is either shut down or operates in chopper braking mode.

[0112] S802: When the wind-solar converter is operating in photovoltaic power generation mode or wind-solar combined power generation mode, the control composite circuit performs maximum power tracking on the photovoltaic array.

[0113] It should be understood that the above steps are not in any particular order. The specific operating mode of the wind-solar converter can be determined by the power station. The host computer of the power station can send control commands to the wind-solar converter, which are used to indicate the specific operating mode of the wind-solar converter.

[0114] The composite circuit includes: a first switching branch, a second switching branch, a third switching branch, and a freewheeling branch; the first terminal of the first switching branch is connected to the positive input terminal of the inverter circuit, the second terminal of the first switching branch is connected to the first terminal of the second switching branch, and the second terminal of the second switching branch is connected to the negative input terminal of the inverter circuit; the freewheeling branch is connected in parallel across the two terminals of the first switching branch; the first terminal of the third switching branch is used to connect to the positive terminal of the photovoltaic array, and the second terminal of the third switching branch is connected to the first terminal of the second switching branch;

[0115] When the wind-solar converter is operating in wind power generation mode, the third switch branch is specifically controlled to be disconnected; when the wind-solar converter enters chopper braking mode, the specific steps include: first controlling the third switch branch to be disconnected, and then controlling the first switch branch and the second switch branch to be connected.

[0116] When the wind-solar converter exits the chopper braking mode, the specific steps include: first, controlling both the first and second switch branches to disconnect, and then controlling the third switch branch to conduct.

[0117] When the wind-solar converter is operating in photovoltaic power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

[0118] When the wind-solar converter operates in the combined wind and solar power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

[0119] Based on the wind-solar converter and control method provided in the above embodiments, this application also provides a new energy system, which will be described in detail below with reference to the accompanying drawings.

[0120] New Energy System Implementation Examples

[0121] See Figure 9 The figure is a schematic diagram of a new energy system provided in an embodiment of this application.

[0122] The new energy system provided in this embodiment includes the wind-solar converter 1000 described in the above embodiments, and also includes: wind turbine 2000, photovoltaic array PV and transformer T;

[0123] The wind turbine 2000 is used to connect to the input terminal of the rectified current in the wind-solar converter 1000;

[0124] The photovoltaic array PV is used to connect to the input terminal of the composite circuit in the wind-solar converter 1000;

[0125] The output terminal of the inverter circuit in the 1000 wind-solar converter is used to connect to the transformer.

[0126] The new energy system provided in this embodiment integrates wind power generation and photovoltaic power generation. Moreover, the wind-solar converter integrates the MPPT function of photovoltaic power and the Chopper function of wind power, which effectively improves the power density and thus reduces costs.

[0127] See Figure 10 This figure is a schematic diagram of another new energy system provided in an embodiment of this application.

[0128] Figure 1 The present invention describes a full-power system. The following describes another application scenario of the wind-solar converter provided in this application embodiment, such as... Figure 10 The doubly fed system shown.

[0129] In this circuit, switch Q2 is the stator switch for the wind turbine generator M. The first terminal of Q2 is connected to the stator of generator M, and the second terminal of Q2 is connected to one end of the grid-connected circuit breaker Q1. The rotor of generator M is connected to the input terminal of AC / DC circuit C1.

[0130] The following is combined Figure 10 Introducing the working modes of a doubly fed system:

[0131] Wind power generation mode: Q2 is closed, C1 provides rotor excitation for the generator, and C2 is used to stabilize the DC bus voltage (the common point between C1 and C2).

[0132] Photovoltaic power generation mode: Q2 is disconnected, C3 operates in MPPT mode, supplying energy to the DC bus, and C2 inverts electrical energy to the grid.

[0133] Wind and solar power generation mode: Q2 is closed, C1 provides rotor excitation for the generator, C2 is used to stabilize the DC bus voltage (common point between C1 and C2), and C3 operates in MPPT mode to supply energy to the DC bus.

[0134] Figure 10 Braking mode of the doubly fed system shown Figure 1 The working principle of the full-power system shown is the same, so it will not be described again here.

[0135] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0136] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0137] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0138] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0139] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wind-solar converter, characterized in that, The wind-solar converter includes: a rectifier circuit, an inverter circuit, and a composite circuit; the input terminal of the rectifier circuit is used to connect to the output terminal of the wind turbine generator; the output terminal of the rectifier circuit is connected to the input terminal of the inverter circuit. The composite circuit includes an integrated photovoltaic maximum power tracking circuit and a wind power chopper braking circuit; the composite circuit includes: a first switching branch, a second switching branch, a third switching branch, and a freewheeling branch; the first switching branch includes at least a first resistor and a first switching device connected in series; the first end of the first switching branch is connected to the positive input terminal of the inverter circuit, the second end of the first switching branch is connected to the first end of the second switching branch, and the second end of the second switching branch is connected to the negative input terminal of the inverter circuit; the freewheeling branch is connected in parallel across the two ends of the first switching branch; the first end of the third switching branch is used to connect to the positive terminal of the photovoltaic array, and the second end of the third switching branch is connected to the first end of the second switching branch; When the wind-solar converter operates in wind power generation mode, the composite circuit is used to exit operation or operate in chopper braking mode; when the wind-solar converter operates in photovoltaic power generation mode or wind-solar combined power generation mode, the composite circuit is used to perform maximum power tracking on the photovoltaic array.

2. The wind-solar converter according to claim 1, characterized in that, When the composite circuit operates in chopper braking mode, the third switch branch is disconnected; when the composite circuit operates in photovoltaic power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion; when the composite circuit operates in wind-solar combined power generation mode, the first switch branch is disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

3. The wind-solar converter according to claim 1, characterized in that, The second switching branch includes at least a second switching device.

4. The wind-solar converter according to claim 3, characterized in that, The third switching branch includes at least an inductor and a third switching device connected in series.

5. The wind-solar converter according to claim 1, characterized in that, The freewheeling branch includes at least a first diode; The anode of the first diode is connected to the second terminal of the first switch branch, and the cathode of the first diode is connected to the first terminal of the first switch branch.

6. The wind-solar converter according to claim 3, characterized in that, The first switching device and the second switching device are integrated into a single switching module.

7. The wind-solar converter according to claim 6, characterized in that, When the photovoltaic array comprises multiple photovoltaic arrays, the composite circuit comprises multiple third switch branches; the multiple photovoltaic arrays and the multiple third switch branches correspond one-to-one.

8. The wind-solar converter according to claim 6, characterized in that, When the photovoltaic array comprises multiple components, the wind-solar converter comprises multiple composite circuits; the multiple photovoltaic arrays and the multiple composite circuits correspond one-to-one.

9. The wind-solar converter according to claim 4, characterized in that, The second and third switching devices are integrated into a single switching module.

10. A control method for a wind-solar converter, characterized in that, The wind-solar converter includes: a rectifier circuit, an inverter circuit, and a composite circuit; the input terminal of the rectifier circuit is connected to the output terminal of the wind turbine; the output terminal of the rectifier circuit is connected to the input terminal of the inverter circuit; the composite circuit includes: a first switching branch, a second switching branch, a third switching branch, and a freewheeling branch; the first switching branch includes at least a first resistor and a first switching device connected in series; the first end of the first switching branch is connected to the positive input terminal of the inverter circuit, the second end of the first switching branch is connected to the first end of the second switching branch, and the second end of the second switching branch is connected to the negative input terminal of the inverter circuit; the freewheeling branch is connected in parallel across the two ends of the first switching branch; the first end of the third switching branch is connected to the positive terminal of the photovoltaic array, and the second end of the third switching branch is connected to the first end of the second switching branch; the composite circuit includes an integrated photovoltaic maximum power tracking circuit and a wind power chopper braking circuit; The method includes: When the wind-solar converter is operating in wind power generation mode, it controls the composite circuit to either exit operation or operate in chopper braking mode. When the wind-solar converter operates in photovoltaic power generation mode or wind-solar combined power generation mode, it controls the composite circuit to perform maximum power tracking on the photovoltaic array.

11. The method according to claim 10, characterized in that, When the wind-solar converter is operating in wind power generation mode, the third switch branch is specifically controlled to disconnect. When the wind-solar converter is operating in photovoltaic power generation mode, the first switch branch is specifically controlled to be disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion. When the wind-solar converter operates in the combined wind and solar power generation mode, the first switch branch is specifically controlled to be disconnected, the third switch branch is turned on, and the second switch branch is used for power conversion.

12. The method according to claim 11, characterized in that, When the wind-solar converter enters the chopper braking mode, specifically including: First, control the third switch branch to disconnect, then control the first switch branch and the second switch branch to connect; When the wind-solar converter exits the chopper braking mode, the specific steps include: First, disconnect both the first and second switch branches, then connect the third switch branch.

13. A new energy system, characterized in that, The wind-solar converter according to any one of claims 1-9 further includes: a wind turbine, a photovoltaic array, and a transformer; The wind turbine is used to connect to the input terminal of the rectified current in the wind-solar converter; The photovoltaic array is used to connect to the input terminal of the composite circuit in the wind-solar converter; The output terminal of the inverter circuit in the wind-solar converter is used to connect to the transformer.

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