Novel wind power converter

Abstract

A novel wind power converter comprises power units, a power connection network and a generator, the power connection network is in circuit connection with a network side power unit and the generator, each power unit is of a five-level topological power unit structure, the number of the power units is two, the power units are arranged on a machine side and a network side respectively, and the network side power unit and the machine side power unit are in circuit connection. The grid-side power unit and the machine-side power unit are correspondingly connected with the grid-side controller and the machine-side controller respectively, the grid-side controller is in circuit connection with the machine-side controller, the grid-side controller is connected with the direct-current unloading circuit, and the direct-current unloading circuit is connected with a positive and negative electrode connecting circuit between the grid-side power unit and the machine-side power unit. And the machine side controller is connected with a three-phase power supply circuit between the machine side power unit and the generator through a crowbar circuit. The invention has the beneficial effects that higher voltage output and higher power grid connection can be realized, system heat dissipation and structure through-flow design are facilitated, and later maintenance and capacity expansion of equipment are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of multi-level applications of wind power converters, and more specifically to a novel wind power converter. Background Art

[0002] Traditional wind power converters generally use a three-level topology with 1700V-class power devices in parallel to obtain a high-voltage and high-power grid connection capacity. Such applications are restricted by the voltage rating of the devices, uneven current sharing when the number of parallel devices increases, and cost, etc., and it is impossible to further obtain higher voltage and power level applications. Summary of the Invention

[0003] The present invention overcomes the deficiencies in the prior art and provides a novel wind power converter.

[0004] The object of the present invention is achieved by the following technical solutions.

[0005] A novel wind power converter includes a power unit, a grid connection, and a generator. The grid connection is respectively connected to the grid-side power unit and the generator through circuits. The power unit adopts a five-level topology power unit structure. The number of power units is two, which are respectively arranged on the machine side and the grid side. The grid-side power unit and the machine-side power unit are connected through circuits. The grid-side power unit and the machine-side power unit are respectively connected to the grid-side controller and the machine-side controller correspondingly. The grid-side controller and the machine-side controller are connected through circuits. The grid-side controller is connected to a DC unloading circuit. The DC unloading circuit is respectively connected to the positive and negative connection circuits between the grid-side power unit and the machine-side power unit. The machine-side controller is connected to the three-phase power supply circuit between the machine-side power unit and the generator through a crowbar circuit.

[0006] The five-level topology power unit structure of the power unit adopts a clamped topology or a flying capacitor topology or a cascaded topology.

[0007] The power unit structure includes: power switches S1 - S8, diodes D1 - D12, and capacitors C1 - C4. The power switches S1 - S8 are sequentially connected in series. The S1 end and the S8 end of the series circuit of the power switches S1 - S8 are respectively connected to the positive and negative poles of the DC power supply V DC The capacitors C1 - C4 are sequentially connected in series. The C1 end and the C4 end of the series circuit of the capacitors C1 - C4 are connected to the circuits connected to the power switches S1 and S8 and the DC power supply V DC respectively. The circuit connecting the power switch S4 and the power switch S5 is connected to the power supply input terminal V0.

[0008] Diodes D1 - D4 are connected in series in sequence. The D1 end of the series circuit of diodes D1 - D4 is arranged on the circuit where power switch tubes S1 and S2 are connected. The D4 end of the series circuit of diodes D1 - D4 is arranged on the circuit where power switch tubes S5 and S6 are connected. The circuit connecting diodes D1 and D2 is connected and set to be in communication with the circuit connecting capacitors C1 and C2;

[0009] Diodes D5 - D8 are connected in series in sequence. The D5 end of the series circuit of diodes D5 - D8 is arranged on the circuit where power switch tubes S2 and S3 are connected. The D8 end of the series circuit of diodes D5 - D8 is arranged on the circuit where S6 and power switch tube S7 are connected. The circuit connecting diodes D6 and D7 is connected and set to be in communication with the circuit connecting capacitors C2 and C3;

[0010] Diodes D9 - D12 are connected in series in sequence. The D9 end of the series circuit of diodes D9 - D12 is arranged on the circuit where power switch tubes S3 and S4 are connected. The D12 end of the series circuit of diodes D9 - D12 is arranged on the circuit where S7 and power switch tube S8 are connected. The circuit connecting diodes D11 and D12 is connected and set to be in communication with the circuit connecting capacitors C3 and C4;

[0011] The power unit structure includes: power switch tubes S1 - S8, capacitors C1 - C4, and diodes D1 - D6. Power switch tubes S1 - S8 are connected in series in sequence. The S1 end and the S8 end of the series circuit of power switch tubes S1 - S8 are respectively connected corresponding to the positive and negative poles of the power supply. Capacitors C1 - C4 are connected in series in sequence. The C1 end and the C4 end of the series circuit of capacitors C1 - C4 are connected and set to be in communication with the circuits where power switch tubes S1 and S8 are connected to the positive and negative poles of the DC power supply respectively. The circuit connecting power switch tubes S4 and S5 is connected and set to be in communication with the power supply input terminal;

[0012] Diodes D3 and D6 are connected in series. One end of diode D3 is arranged on the circuit where power switch tubes S3 and S4 are connected. One end of diode D6 is arranged on the circuit where power switch tubes S7 and S8 are connected. The circuit connecting diodes D3 and D6 is connected and set to be in communication with the circuit connecting capacitors C3 and C4;

[0013] The diodes D1 and D4 are connected in series. One end of the diode D1 is arranged on the circuit where the power switch tubes S1 and S2 are connected. One end of the diode D4 is arranged on the circuit where the power switch tubes S5 and S6 are connected. The circuit where the diodes D1 and D4 are connected is connected and set to be in communication with the circuit where the capacitors C1 and C2 are connected;

[0014] The diodes D2 and D5 are connected in series. One end of the diode D2 is arranged on the circuit where the power switch tubes S2 and S3 are connected. One end of the diode D5 is arranged on the circuit where the power switch tubes S6 and S7 are connected. The circuit where the diodes D2 and D5 are connected is connected and set to be in communication with the circuit where the capacitors C2 and C3 are connected.

[0015] The power unit structure includes:

[0016] Power switch tubes S1 - S8, capacitors Cf1 - Cf6 and capacitors C1 - C4. The positive power supply, power switch tubes S1 - S8 and the negative power supply are connected in series in sequence. The capacitors C1 - C4 are connected in series,

[0017] The capacitors C1 and C4 are respectively connected to the positive power supply and the negative power supply,

[0018] One end of the capacitor Cf1 is connected and set to be in communication with the circuit where the power switch tubes S3 and S4 are connected. The other end of the capacitor Cf1 is connected and set to be in communication with the circuit where the power switch tubes S5 and S6 are connected,

[0019] The capacitors Cf2 and Cf3 are connected in series. One end of the capacitor Cf2 is connected and set to be in communication with the circuit where the power switch tubes S2 and S3 are connected. One end of the capacitor Cf3 is connected and set to be in communication with the circuit where the power switch tubes S6 and S7 are connected,

[0020] The capacitors Cf4, Cf5 and Cf6 are connected in series in sequence. One end of the capacitor Cf4 is connected and set to be in communication with the circuit where the power switch tubes S1 and S2 are connected. One end of the capacitor Cf6 is connected and set to be in communication with the circuit where the power switch tubes S7 and S8 are connected.

[0021] The power unit structure includes: power switch tubes S1 - S4, capacitors C1 - C2 and diodes D1 - D4,

[0022] The power switch tube S1 and the diode D1 are connected in series. One end of the power switch tube S1 is connected to one end of the capacitor C1, and the other end of the diode D1 is connected to the other end of the capacitor C1. The power switch tube S2 and the diode D2 are connected in series. The circuit where the power switch tube S2 and the diode D2 are connected is connected to the positive pole of the power supply. One end of the power switch tube S2 is connected to one end of the capacitor C1, and the other end of the diode D2 is connected to the other end of the capacitor C1.

[0023] The power switch tube S3 and the diode D3 are connected in series. One end of the power switch tube S3 is connected to one end of the capacitor C2, and the other end of the diode D3 is connected to the other end of the capacitor C2. The power switch tube S4 and the diode D4 are connected in series. The circuit where the power switch tube S4 and the diode D4 are connected is connected to the negative pole of the power supply. One end of the power switch tube S4 is connected to one end of the capacitor C2, and the other end of the diode D4 is connected to the other end of the capacitor C2.

[0024] The circuit where the power switch tube S1 and the diode D1 are connected is connected to the circuit where the power switch tube S4 and the diode D4 are connected.

[0025] The power unit structure includes: topology a, topology b, and topology c. The structures of topology a, topology b, and topology c are the same.

[0026] On topology a, there are power switch tube groups Sa5, Sa6, Sa7, and Sa8. The power switch tube groups Sa5, Sa6, Sa7, and Sa8 are connected in series in sequence. The power switch tubes Sa3, Sa1, Sa2, and Sa4 are connected in series in sequence. One end of the power switch tube Sa3 is connected to the circuit where the power switch tube groups Sa5 and Sa6 are connected. One end of the power switch tube Sa4 is connected to the circuit where the power switch tube groups Sa7 and Sa8 are connected. Both ends of the capacitor Cfa are respectively connected to the power switch tubes Sa1 and Sa2. One end of the inductor coil L is connected to the circuit where the power switch tubes Sa1 and Sa2 are connected, and the other end of the inductor coil L is connected to the resistor R. The resistors R set on topology a, topology b, and topology c are connected to each other.

[0027] The power switch tube groups Sa5 set on topology a, topology b, and topology c are connected to each other.

[0028] The circuits where the power switch tube groups Sa6 and Sa7 are connected on topology a, topology b, and topology c are connected to each other.

[0029] The power switch tube groups Sa8 set on topology a, topology b, and topology c are connected to each other.

[0030] The positive terminal of transformer U is connected to the circuits on topologies a, b, and c that are interconnected through power switch tube group Sa5.

[0031] The negative terminal of transformer U is connected to the circuits on topologies a, b, and c that are interconnected through power switch tube group Sa8.

[0032] Capacitor C1 and capacitor C2 are connected in series. Capacitor C1 is connected to the positive terminal, and capacitor C2 is connected to the negative terminal.

[0033] The circuit where capacitor C1 and capacitor C2 are connected is interconnected with the circuit that is connected between power switch tube group Sa6 and power switch tube group Sa7 provided on topologies a, b, and c.

[0034] Power switch tube group Sa5 is set with two power switch tubes Sa5 connected in series. Power switch tube group Sa6 is set with two power switch tubes Sa6 connected in series. Power switch tube group Sa7 is set with two power switch tubes Sa7 connected in series. Power switch tube group Sa8 is set with two power switch tubes Sa8 connected in series.

[0035] The beneficial effects of the present invention are as follows:

[0036] 1) Power devices such as 1200V or 1700V IGBTs have low costs and mature applications. The existing 1700V IGBT three-level topology can only achieve an output of 1140V. When the power reaches a certain level, due to current limitations, there is no cost advantage and the technical risk is increased. Using existing mature 1200V or 1700V specification IGBTs (Insulated Gate Bipolar Transistors), a five-level topology can achieve a higher voltage output and realize grid connection with a larger power.

[0037] 2) Using 2300V IGBTs or higher specification IGBTs with the same topology, compared with the five-level topology, the cost of achieving grid connection with the same voltage and power is higher.

[0038] 3) Using low-voltage devices has a lower du / dt and di / dt, which can reduce system noise and interference.

[0039] 4) The application of low-voltage power devices can reduce the safety standard level inside the power module and realize miniaturized design.

[0040] 5) It is beneficial for system heat dissipation and structural current-carrying design.

[0041] 6) It can further reduce grid-connected harmonics and reduce the size of system magnetic devices.

[0042] 7) It is beneficial for the later maintenance and expansion of system equipment. Description of the Drawings

[0043] Figure 1 is the structural schematic diagram of the present invention;

[0044] Figure 2 is the waveform effect diagram of this solution;

[0045] Figure 3 is the circuit diagram of the power unit in the second embodiment;

[0046] Figure 4 is the circuit diagram of the power unit in the third embodiment;

[0047] Figure 5 is the circuit diagram of the power unit in the fourth embodiment;

[0048] Figure 6 is the circuit diagram of the power unit in the fifth embodiment;

[0049] Figure 7 is the circuit diagram of the power unit in the sixth embodiment;

[0050] In the figure: 1, grid-side power unit; 2, machine-side power unit; 3, grid-side controller; 4, machine-side controller; 5, DC unloading circuit; 6, crowbar circuit. Specific embodiments

[0051] The technical solution of the present invention will be further described below through specific embodiments.

[0052] Embodiment 1

[0053] As Figure 1 shown, a new type of wind power converter includes a power unit, a power grid connection, and a generator. The power grid connection is respectively connected to the grid-side power unit 1 and the generator circuit. The power unit adopts a five-level topology power unit structure. The number of power units is two, which are respectively arranged on the machine side and the grid side. The grid-side power unit 1 and the machine-side power unit 2 are connected by a circuit. The grid-side power unit 1 and the machine-side power unit 2 are respectively connected to the grid-side controller 3 and the machine-side controller 4 correspondingly. The grid-side controller 3 and the machine-side controller 4 are connected by a circuit. The grid-side controller 3 is connected to the DC unloading circuit 5. The DC unloading circuit 5 is respectively connected to the positive and negative connection circuits between the grid-side power unit 1 and the machine-side power unit 2. The machine-side controller 4 is connected to the three-phase power supply circuit between the machine-side power unit 2 and the generator through the crowbar circuit 6.

[0054] The working principle of this solution is as follows. The power conversion between the power grid and the generator is carried out through the five-level topology power unit structure. The grid-side power unit 1 and the machine-side power unit 2 are controlled by the grid-side controller 3 and the machine-side controller 4 respectively. In this embodiment, the controller circuit is composed of a DSP controller, a wave generation circuit, a sampling circuit, a communication circuit, etc. The circuit structures of the grid-side controller 3 and the machine-side controller 4 are the same. The DC unloading circuit 5, i.e., the chopper circuit, is used to chop the wave and discharge the bus. The chopper circuit is a mature circuit idea in the art and will change according to the topology changes of the grid-side and machine-side power units. In use, the bus is divided into several groups according to the circuit topology, and the device selection and the number of choppers used are determined according to the number of groups. The crowbar circuit 6 is used for overvoltage / overcurrent protection.

[0055] As Figure 2 shown, it can be seen from the waveforms in the figure that compared with the three-level, the same bus voltage will be divided into more equal parts, the voltage applied to the reactance each time is smaller, and the corresponding high-frequency ripple will be smaller. Under the same output voltage, the withstand voltage of the switching device will be reduced. For example, in an 1800V system, if it is designed according to the three-level, IGBTs with a withstand voltage of 2300V need to be selected, while if it is designed according to the five-level, only IGBTs with a withstand voltage of 1700V need to be selected, and the corresponding cost will be lower and the loss will also be lower.

[0056] Furthermore, the five-level topology power unit structure of the power unit adopts a clamped topology, a flying capacitor topology, or a cascaded topology. In actual use, various hybrid topologies can be adopted according to needs.

[0057] Embodiment 2

[0058] As Figure 3 shown, on the basis of Embodiment 1, the power unit structure includes: power switching transistors S1 - S8, diodes D1 - D12, and capacitors C1 - C4. The power switching transistors S1 - S8 are connected in series in sequence. The S1 end and the S8 end of the series circuit of the power switching transistors S1 - S8 are respectively connected to the positive and negative poles of the DC power supply V DC . The capacitors C1 - C4 are connected in series in sequence. The C1 end and the C4 end of the series circuit of the capacitors C1 - C4 are connected to the circuits connected to the power switching transistors S1 and S8 and the DC power supply V DC respectively. The circuit connecting the power switching transistor S4 and the power switching transistor S5 is connected to the power input terminal V0.

[0059] Diodes D1 - D4 are connected in series in sequence. The D1 end of the series circuit of diodes D1 - D4 is set on the circuit where power switch tubes S1 and S2 are connected. The D4 end of the series circuit of diodes D1 - D4 is set on the circuit where power switch tubes S5 and S6 are connected. The circuit connecting diodes D1 and D2 is connected and set to be in communication with the circuit connecting capacitors C1 and C2;

[0060] Diodes D5 - D8 are connected in series in sequence. The D5 end of the series circuit of diodes D5 - D8 is set on the circuit where power switch tubes S2 and S3 are connected. The D8 end of the series circuit of diodes D5 - D8 is set on the circuit where S6 and power switch tube S7 are connected. The circuit connecting diodes D6 and D7 is connected and set to be in communication with the circuit connecting capacitors C2 and C3;

[0061] Diodes D9 - D12 are connected in series in sequence. The D9 end of the series circuit of diodes D9 - D12 is set on the circuit where power switch tubes S3 and S4 are connected. The D12 end of the series circuit of diodes D9 - D12 is set on the circuit where S7 and power switch tube S8 are connected. The circuit connecting diodes D11 and D12 is connected and set to be in communication with the circuit connecting capacitors C3 and C4;

[0062] In this embodiment, by controlling the actions of the signals S1 - s8 of the switch tubes, 6 kinds of switch states can be output, corresponding to five levels. The three routes in the figure include:

[0063] The circuit route from the input terminal V0 passing through power switch tubes S4, S3, S2 to power switch tube S1 in sequence;

[0064] The circuit route from the input terminal V0 passing through power switch tubes S4, S3, S2, diode D1 to capacitor C2 in sequence;

[0065] The circuit route from the input terminal V0 passing through power switch tubes S4, S3, diode D5 to the circuit connecting diodes D6 and capacitors C2 and C3 in sequence;

[0066] The above three routes respectively correspond to the current paths formed by 3 kinds of action combinations in the positive half - cycle, and the corresponding levels are U / 2, U / 4, 0 in sequence. Similarly, the corresponding levels in the negative half - cycle are -U / 2, -U / 4, 0 in sequence; combined, it is five - level.

[0067] Embodiment Three

[0068] As Figure 4As shown in the figure, on the basis of Embodiment 1, the power unit structure includes: power switching transistors S1 - S8, capacitors C1 - C4, and diodes D1 - D6. The power switching transistors S1 - S8 are serially arranged in sequence. The S1 end and the S8 end of the series circuit of the power switching transistors S1 - S8 are respectively connected corresponding to the positive and negative poles of the power supply. The capacitors C1 - C4 are serially arranged in sequence. The C1 end and the C4 end of the series circuit of the capacitors C1 - C4 are connected to the circuits where the power switching transistors S1 and S8 are connected to the positive and negative poles of the DC power supply. The circuit connecting the power switching transistor S4 and the power switching transistor S5 is connected to the power input terminal;

[0069] The diodes D3 and D6 are serially arranged. One end of the diode D3 is arranged on the circuit connecting the power switching transistor S3 and the power switching transistor S4. One end of the diode D6 is arranged on the circuit connecting the power switching transistor S7 and the power switching transistor S8. The circuit connecting the diodes D3 and D6 is connected to the circuit connecting the capacitors C3 and C4;

[0070] The diodes D1 and D4 are serially arranged. One end of the diode D1 is arranged on the circuit connecting the power switching transistor S1 and the power switching transistor S2. One end of the diode D4 is arranged on the circuit connecting the power switching transistor S5 and the power switching transistor S6. The circuit connecting the diodes D1 and D4 is connected to the circuit connecting the capacitors C1 and C2;

[0071] The diodes D2 and D5 are serially arranged. One end of the diode D2 is arranged on the circuit connecting the power switching transistor S2 and the power switching transistor S3. One end of the diode D5 is arranged on the circuit connecting the power switching transistor S6 and the power switching transistor S7. The circuit connecting the diodes D2 and D5 is connected to the circuit connecting the capacitors C2 and C3;

[0072] In this embodiment, by controlling the signals S1 - s8 of the switching transistors to act, 6 kinds of switching states and corresponding five levels can be output.

[0073] The three routes in the figure include:

[0074] The circuit route from the input terminal passing through the power switching transistors S4, S3, S2 to the power switching transistor S1 in sequence;

[0075] The circuit route from the input terminal passing through the power switching transistors S4, S3, S2 to the circuit connecting the diode D1 and the capacitors C2 and C1 in sequence;

[0076] The circuit path from the input terminal passes through the power switch tube S4, the power switch tube S3 in sequence to the diode D2 and is connected to the capacitor C2 and the capacitor C3;

[0077] The above circuit paths respectively correspond to the current paths formed by three action combinations in the positive half cycle, and the corresponding levels are U / 2, U / 4, 0 in sequence. Similarly, the corresponding levels in the negative half cycle are -U / 2, -U / 4, 0 in sequence; combined, it is a five-level.

[0078] Embodiment 4

[0079] As Figure 5 shown, on the basis of Embodiment 1, the power unit structure includes: power switch tubes S1 - S8, capacitors Cf1 - Cf6 and capacitors C1 - C4. The positive power supply, power switch tubes S1 - S8 and the negative power supply are connected in series in sequence, and capacitors C1 - C4 are connected in series.

[0080] Capacitor C1 and capacitor C4 are respectively connected to the positive power supply and the negative power supply.

[0081] One end of capacitor Cf1 is connected to the circuit where power switch tubes S3 and S4 are connected, and the other end of capacitor Cf1 is connected to the circuit where power switch tubes S5 and S6 are connected.

[0082] Capacitors Cf2 and Cf3 are connected in series. One end of capacitor Cf2 is connected to the circuit where power switch tubes S2 and S3 are connected, and one end of capacitor Cf3 is connected to the circuit where power switch tubes S6 and S7 are connected.

[0083] Capacitors Cf4, Cf5 and Cf6 are connected in series in sequence. One end of capacitor Cf4 is connected to the circuit where power switch tubes S1 and S2 are connected, and one end of capacitor Cf6 is connected to the circuit where power switch tubes S7 and S8 are connected.

[0084] In this embodiment, assuming the total voltage is U, the sum of capacitors C1 - C4 in the fourth column is U, the sum of capacitors Cf4, Cf5 and Cf6 in the third column is 3 / 4U, the sum of capacitors Cf2 and Cf3 in the second column is 1 / 2U, and capacitor Cf1 in the first column is 1 / 4U. The capacitor circuit in the first column and the capacitor circuit in the third column alternately form positive or negative U / 4, and the capacitor circuit in the second column forms the intermediate 0 level.

[0085] Embodiment 5

[0086] As Figure 6As shown, on the basis of Embodiment 1, the power unit structure includes: power switching transistors S1 - S4, capacitors C1 - C2, and diodes D1 - D4.

[0087] The power switching transistor S1 and the diode D1 are connected in series. One end of the power switching transistor S1 and the capacitor C1 are connected, and the other end of the diode D1 and the capacitor C1 are connected. The power switching transistor S2 and the diode D2 are connected in series. The circuit where the power switching transistor S2 and the diode D2 are connected is connected to the positive electrode of the power supply. One end of the power switching transistor S2 and the capacitor C1 are connected, and the other end of the diode D2 and the capacitor C1 are connected.

[0088] The power switching transistor S3 and the diode D3 are connected in series. One end of the power switching transistor S3 and the capacitor C2 are connected, and the other end of the diode D3 and the capacitor C2 are connected. The power switching transistor S4 and the diode D4 are connected in series. The circuit where the power switching transistor S4 and the diode D4 are connected is connected to the negative electrode of the power supply. One end of the power switching transistor S4 and the capacitor C2 are connected, and the other end of the diode D4 and the capacitor C2 are connected.

[0089] The circuit where the power switching transistor S1 and the diode D1 are connected is connected to the circuit where the power switching transistor S4 and the diode D4 are connected.

[0090] In this embodiment, the levels are connected in series by the H - bridge cascade method. One H - bridge represents a minimum level unit. Two H - bridges can achieve three combinations of 0, 1, and 2. At the same time, considering the positive and negative half - cycles together, a 5 - level is formed, and the 0 - level is common.

[0091] Embodiment 6

[0092] As Figure 7 shown, on the basis of Embodiment 1, the power unit structure includes: topology a, topology b, and topology c. The structures of topology a, topology b, and topology c are the same.

[0093] On the topology a, there are power switch tube groups Sa5, Sa6, Sa7 and Sa8. The power switch tube groups Sa5, Sa6, Sa7 and Sa8 are arranged in series in sequence. The power switch tubes Sa3, Sa1, Sa2 and Sa4 are arranged in series in sequence. One end of the power switch tube Sa3 is connected to the circuit connected between the power switch tube group Sa5 and the power switch tube group Sa6. One end of the power switch tube Sa4 is connected to the circuit connected between the power switch tube group Sa7 and the power switch tube group Sa8. Both ends of the capacitor Cfa are respectively connected to the power switch tubes Sa1 and Sa2. One end of the inductor coil L is connected to the circuit where the power switch tubes Sa1 and Sa2 are connected. The other end of the inductor coil L is connected to the resistor R. The resistors R set on the topologies a, b and c are connected to each other.

[0094] The power switch tube groups Sa5 set on the topologies a, b and c are connected to each other.

[0095] The circuits connecting the power switch tube group Sa6 and the power switch tube group Sa7 set on the topologies a, b and c are connected to each other.

[0096] The power switch tube groups Sa8 set on the topologies a, b and c are connected to each other.

[0097] The positive terminal of the transformer U is connected to the circuit connected through the power switch tube group Sa5 on the topologies a, b and c.

[0098] The negative terminal of the transformer U is connected to the circuit connected through the power switch tube group Sa8 on the topologies a, b and c.

[0099] The capacitor C1 and the capacitor C2 are connected in series. The capacitor C1 is connected to the positive terminal, and the capacitor C2 is connected to the negative terminal.

[0100] The circuit where the capacitor C1 and the capacitor C2 are connected is connected to the circuit connecting the power switch tube group Sa6 and the power switch tube group Sa7 set on the topologies a, b and c.

[0101] The power switch tube group Sa5 is set with two power switch tubes Sa5 connected in series. The power switch tube group Sa6 is set with two power switch tubes Sa6 connected in series. The power switch tube group Sa7 is set with two power switch tubes Sa7 connected in series. The power switch tube group Sa8 is set with two power switch tubes Sa8 connected in series.

[0102] In this embodiment, this embodiment includes the topologies of three-phase electricity of a, b, and c, and the structures of topologies a, b, and c are the same. Taking topology a as an example for illustration:

[0103] By controlling the actions of the signals Sa1 - Sa8 of the switching tubes, each of the a, b, and c phases can output eight switching states and correspond to five levels. The following circuit paths respectively correspond to the current paths formed by 4 action combinations in the positive half cycle, and the specific paths are as follows.

[0104] Route 1 is from the power switching tube group Sa5, sequentially passing through the power switching tube Sa3, the power switching tube Sa1, the inductor coil L to the resistor R.

[0105] Route 2 is from the power switching tube group Sa5, sequentially passing through the power switching tube Sa3, the power switching tube Sa2, the inductor coil L to the resistor R.

[0106] Route 3 is from the power switching tube group Sa6, sequentially passing through the power switching tube Sa3, the capacitor Cfa, the power switching tube Sa2, the inductor coil L to the resistor R.

[0107] Route 4 is from the power switching tube group Sa6, sequentially passing through the power switching tube Sa3, the power switching tube Sa1, the inductor coil L to the resistor R.

[0108] The levels corresponding to the above routes are U / 2, U / 4, U / 4, 0 in sequence. Similarly, the levels corresponding to the negative half cycle are -U / 2, -U / 4, -U / 4, 0 in sequence; combined, it is a five-level.

[0109] Furthermore, the power switching tube group Sa5 is set with two power switching tubes Sa5 connected in series, the power switching tube group Sa6 is set with two power switching tubes Sa6 connected in series, the power switching tube group Sa7 is set with two power switching tubes Sa7 connected in series, and the power switching tube group Sa8 is set with two power switching tubes Sa8 connected in series. This is because the withstand voltage requirement of the power switching tubes at this position is U / 2 and two need to be used in series, or select a power switching tube whose withstand voltage is twice that of other devices.

[0110] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as used to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A new type of wind power converter, characterized in that: It includes a power unit, a grid connection, and a generator. The grid connection is circuit-connected to the grid-side power unit and the generator respectively. The power unit adopts a five-level topology power unit structure. The number of power units is two, which are respectively arranged on the machine side and the grid side. The grid-side power unit and the machine-side power unit are circuit-connected. The grid-side power unit and the machine-side power unit are respectively connected to the grid-side controller and the machine-side controller correspondingly. The grid-side controller and the machine-side controller are circuit-connected. The grid-side controller is circuit-connected to the DC dump circuit. The DC dump circuit is connected to the positive and negative connection circuits between the grid-side power unit and the machine-side power unit respectively. The machine-side controller is connected to the three-phase power supply circuit between the machine-side power unit and the generator through a crowbar circuit.

2. The novel wind power converter according to claim 1, characterized in that: The five-level topology power unit structure of the power unit adopts a clamped topology, a flying capacitor topology, or a cascaded topology.

3. A novel wind power converter according to claim 1, characterized in that, The power unit structure includes: power switching transistors S1 - S8, diodes D1 - D12, and capacitors C1 - C4. The power switching transistors S1 - S8 are sequentially connected in series. The S1 end and the S8 end of the series circuit of the power switching transistors S1 - S8 are respectively connected to the positive and negative terminals of the DC power supply V DC . The capacitors C1 - C4 are sequentially connected in series. The C1 end and the C4 end of the series circuit of the capacitors C1 - C4 are connected to the circuits connected to the power switching transistors S1 and S8 and the DC power supply V DC respectively. The circuit connecting the power switching transistor S4 and the power switching transistor S5 is connected to the power input terminal V0; Diodes D1 - D4 are arranged in series in sequence. The D1 end of the series circuit of diodes D1 - D4 is set on the circuit where power switch tube S1 and power switch tube S2 are connected. The D4 end of the series circuit of diodes D1 - D4 is set on the circuit where power switch tube S5 and power switch tube S6 are connected. The circuit where D1 and D2 are connected is connected and set in communication with the circuit where capacitor C1 and capacitor C2 are connected; Diodes D5 - D8 are arranged in series in sequence. The D5 end of the series circuit of diodes D5 - D8 is set on the circuit where power switch tube S2 and power switch tube S3 are connected. The D8 end of the series circuit of diodes D5 - D8 is set on the circuit where S6 and power switch tube S7 are connected. The circuit where D6 and D7 are connected is connected and set in communication with the circuit where capacitor C2 and capacitor C3 are connected; Diodes D9 - D12 are arranged in series in sequence. The D9 end of the series circuit of diodes D9 - D12 is set on the circuit where power switch tube S3 and power switch tube S4 are connected. The D12 end of the series circuit of diodes D9 - D12 is set on the circuit where S7 and power switch tube S8 are connected. The circuit where D11 and D12 are connected is connected and set in communication with the circuit where capacitor C3 and capacitor C4 are connected.

4. A novel wind power converter according to claim 1, characterized in that, The power unit structure includes: power switch tubes S1 - S8, capacitors C1 - C4, and diodes D1 - D6. Power switch tubes S1 - S8 are arranged in series in sequence. The S1 end and the S8 end of the series circuit of power switch tubes S1 - S8 are respectively connected to the positive and negative poles of the power supply correspondingly. Capacitors C1 - C4 are arranged in series in sequence. The C1 end and the C4 end of the series circuit of capacitors C1 - C4 are connected and set in communication with the circuits where power switch tube S1, power switch tube S8 are connected to the positive and negative poles of the DC power supply respectively. The circuit where power switch tube S4 and power switch tube S5 are connected is connected and set in communication with the power supply input end; The diodes D3 and D6 are connected in series. One end of the diode D3 is disposed on the circuit where the power switch tubes S3 and S4 are connected, and one end of the diode D6 is disposed on the circuit where the power switch tubes S7 and S8 are connected. The circuit where the diodes D3 and D6 are connected is connected to the circuit where the capacitors C3 and C4 are connected; The diodes D1 and D4 are connected in series. One end of the diode D1 is disposed on the circuit where the power switch tubes S1 and S2 are connected, and one end of the diode D4 is disposed on the circuit where the power switch tubes S5 and S6 are connected. The circuit where the diodes D1 and D4 are connected is connected to the circuit where the capacitors C1 and C2 are connected; The diodes D2 and D5 are connected in series. One end of the diode D2 is disposed on the circuit where the power switch tubes S2 and S3 are connected, and one end of the diode D5 is disposed on the circuit where the power switch tubes S6 and S7 are connected. The circuit where the diodes D2 and D5 are connected is connected to the circuit where the capacitors C2 and C3 are connected.

5. A novel wind power converter according to claim 1, characterized in that, The power unit structure includes: power switch tubes S1 - S8, capacitors Cf1 - Cf6, and capacitors C1 - C4. The positive power supply, the power switch tubes S1 - S8, and the negative power supply are connected in series in sequence. The capacitors C1 - C4 are connected in series, The capacitors C1 and C4 are respectively connected to the positive power supply and the negative power supply, One end of the capacitor Cf1 is connected to the circuit where the power switch tubes S3 and S4 are connected, and the other end of the capacitor Cf1 is connected to the circuit where the power switch tubes S5 and S6 are connected, The capacitors Cf2 and Cf3 are connected in series. One end of the capacitor Cf2 is connected to the circuit where the power switch tubes S2 and S3 are connected, and one end of the capacitor Cf3 is connected to the circuit where the power switch tubes S6 and S7 are connected, The capacitors Cf4, Cf5, and Cf6 are connected in series in sequence. One end of the capacitor Cf4 is connected to the circuit where the power switch tubes S1 and S2 are connected, and one end of the capacitor Cf6 is connected to the circuit where the power switch tubes S7 and S8 are connected.

6. A novel wind power converter according to claim 1, characterized in that, The power unit structure includes: power switch tubes S1 - S4, capacitors C1 - C2, and diodes D1 - D4, The power switch tube S1 and the diode D1 are connected in series. One end of the power switch tube S1 is connected to one end of the capacitor C1, and the other end of the diode D1 is connected to the other end of the capacitor C1. The power switch tube S2 and the diode D2 are connected in series. The circuit where the power switch tube S2 and the diode D2 are connected is connected to the positive power supply. One end of the power switch tube S2 is connected to one end of the capacitor C1, and the other end of the diode D2 is connected to the other end of the capacitor C1, The power switch tube S3 and the diode D3 are connected in series. One end of the power switch tube S3 is connected to one end of the capacitor C2, and the other end of the diode D3 is connected to the other end of the capacitor C2. The power switch tube S4 and the diode D4 are connected in series. The circuit connected by the power switch tube S4 and the diode D4 is connected to the negative pole of the power supply. One end of the power switch tube S4 is connected to one end of the capacitor C2, and the other end of the diode D4 is connected to the other end of the capacitor C2. The circuit connected by the power switch tube S1 and the diode D1 is connected to the circuit connected by the power switch tube S4 and the diode D4.

7. A novel wind power converter according to claim 1, characterized in that, The power unit structure includes: topology a, topology b, and topology c. The structures of topology a, topology b, and topology c are the same. On topology a, there are power switch tube groups Sa5, Sa6, Sa7, and Sa8. The power switch tube groups Sa5, Sa6, Sa7, and Sa8 are connected in series in sequence. The power switch tubes Sa3, Sa1, Sa2, and Sa4 are connected in series in sequence. One end of the power switch tube Sa3 is connected to the circuit connected between the power switch tube groups Sa5 and Sa6. One end of the power switch tube Sa4 is connected to the circuit connected between the power switch tube groups Sa7 and Sa8. Both ends of the capacitor Cfa are respectively connected to the power switch tubes Sa1 and Sa2. One end of the inductor coil L is connected to the circuit connected by the power switch tubes Sa1 and Sa2, and the other end of the inductor coil L is connected to the resistor R. The resistors R set on topology a, topology b, and topology c are connected to each other. The power switch tube groups Sa5 set on topology a, topology b, and topology c are connected to each other. The circuits connected between the power switch tube groups Sa6 and Sa7 set on topology a, topology b, and topology c are connected to each other. The power switch tube groups Sa8 set on topology a, topology b, and topology c are connected to each other. The positive terminal of the transformer U is connected to the circuit connected by the power switch tube groups Sa5 on topology a, topology b, and topology c. The negative terminal of the transformer U is connected to the circuit connected by the power switch tube groups Sa8 on topology a, topology b, and topology c. The capacitor C1 and the capacitor C2 are connected in series. The capacitor C1 is connected to the positive terminal, and the capacitor C2 is connected to the negative terminal. The circuit connected by the capacitor C1 and the capacitor C2 is connected to the circuit connected between the power switch tube groups Sa6 and Sa7 set on topology a, topology b, and topology c.

8. A novel wind power converter according to claim 7, characterized in that: The power switch tube group Sa5 is composed of two power switch tubes Sa5 connected in series. The power switch tube group Sa6 is composed of two power switch tubes Sa6 connected in series. The power switch tube group Sa7 is composed of two power switch tubes Sa7 connected in series. The power switch tube group Sa8 is composed of two power switch tubes Sa8 connected in series.

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