CN206117183U - Wind generating set - Google Patents

Abstract

A wind power generating set, including a transformer, a converter, a generator, a wind turbine, and a tower connected in sequence; the converter includes a controller, a grid-side converter and a machine-side converter connected to the controller, and the grid-side converter and The transformer is connected, the machine-side converter is connected to the generator, the generator is connected to the wind turbine, and the wind turbine is installed on the top of the tower. The high-voltage side winding of the transformer is connected to the external power grid through the high-voltage side switch; The low-voltage side winding A of the power interface, the leakage inductance per unit value of winding A is greater than or equal to 5%, and is connected to the grid-side converter through the low-voltage side switch through its power interface; the converter includes a voltage sampling circuit connected to the controller, The circuit is set on the high-voltage side winding of the transformer, or the low-voltage side winding of the transformer includes at least one set of low-voltage side winding B providing a signal interface, and the circuit is set on the winding B signal interface. The utility model reduces the circuit cost and construction cost of the wind power generating set.

Description

a wind turbine

technical field

The utility model relates to a wind power generating set.

Background technique

High-power (megawatt-class) wind turbines are generally divided into doubly-fed wind turbines and full-power wind turbines.

As shown in FIG. 1 , the existing doubly-fed wind power generating set generally includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence. The wind turbine includes blades and a gearbox, and the generator is mechanically connected to the wind turbine, all of which are installed on the top of the tower. The transformer generally includes a high-voltage side switch, a transformer body and a low-voltage side switch; the transformer body is composed of a high-voltage side winding and a low-voltage side winding, the high-voltage side winding is connected to the external power grid through the high-voltage side switch, and the low-voltage side winding is connected to the transformer through the low-voltage side switch. connected to the streamer. The converter generally includes a controller, a grid-side converter, a machine-side converter, a low-voltage side switch, a grid-side filter, and a stator switch, among which the grid-side converter and the machine-side converter are connected through a DC bus, and the grid-side filter The grid-side converter is composed of filter inductors and filter capacitors. The grid-side converter is connected to the transformer through the grid-side filter and the low-voltage side switch. The machine-side converter is connected to the rotor winding of the doubly-fed generator. The stator winding of the doubly-fed generator is connected to the contactor and The low side switch is also connected to the transformer. In order to supply power to the internal equipment of the wind turbine, the converter often needs to be equipped with an auxiliary transformer.

As shown in FIG. 2 , the existing full-power wind power generating set generally includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence. The wind turbine includes blades, and the generator is mechanically connected to the wind turbine, all of which are installed on the top of the tower. The transformer generally includes a high-voltage side switch, a transformer body and a low-voltage side switch; the transformer body is composed of a high-voltage side winding and a low-voltage side winding, and the high-voltage side winding is connected to the external power grid through the high-voltage side switch; the low-voltage side winding is connected to the transformer through the low-voltage side switch. connected to the streamer. The converter generally includes a controller, a grid-side converter, a machine-side converter, a low-voltage side switch, and a grid-side filter, among which the grid-side converter and the machine-side converter are connected through a DC bus, and the grid-side Composed of inductors and filter capacitors, the grid-side converter is connected to the transformer through a grid-side filter and a low-voltage side switch, and the machine-side converter is connected to the stator winding of a synchronous or asynchronous generator. In order to supply power to the internal equipment of the wind turbine, the converter often needs to be equipped with an auxiliary transformer.

The existing high-power wind turbines have the following defects:

First of all, transformers and converters are independent of each other in the circuit, and each has its own power distribution switch, which not only causes some circuit components to be set repeatedly, but also cannot utilize the respective circuit characteristics of transformers and converters to simplify the circuit structure and reduce circuit components , for the purpose of reducing circuit cost.

Secondly, since the transformer and the converter are installed independently of each other in terms of physical layout, the converter is usually installed inside the tower, and the transformer is installed outside the tower to form a box-type transformer, resulting in the connection between the transformer and the converter. It is often necessary to lay long and high-current cables, which increases the construction cost of the wind power generating set.

Utility model content

The technical problem to be solved by the utility model is to provide a wind power generating set, which overcomes the defects of high transformer and converter circuit cost and high construction cost existing in the existing high-power wind power generating set.

The technical solution adopted by the utility model to solve the technical problem is: to construct a wind power generating set, including a transformer, a converter, a generator, a wind turbine and a tower connected in sequence; the converter includes a controller, and the The controller controls the grid-side converter and the machine-side converter connected through the DC bus, the grid-side converter is electrically connected to the transformer, the machine-side converter is electrically connected to the generator, and the generator is connected to the wind power The wind turbine is installed on the top of the tower, and the high-voltage side winding of the transformer is connected to the external power grid through the high-voltage side switch;

It is characterized in that the low-voltage side winding of the transformer includes at least one set of low-voltage side windings A that provide power interfaces, the leakage inductance per unit value corresponding to each of the low-voltage side windings A is greater than or equal to 5%, and through its power interface through the low-voltage side A switch is connected to the grid-side converter;

The converter includes a voltage sampling circuit connected to the controller; the voltage sampling circuit is arranged on the high-voltage side winding of the transformer, or the low-voltage side winding of the transformer includes at least one set of low-voltage side winding B that provides a signal interface, The voltage sampling circuit is arranged on the signal interface of the low-voltage side winding B.

In the wind power generating set of the present utility model, the generator is a doubly-fed generator;

The transformer includes a set of the low-voltage side winding A, the power interface of the low-voltage side winding A is connected to the grid-side converter of the converter through a low-voltage side switch, and connected to the doubly-fed generator through a grid-connected switch the stator winding;

Or the transformer includes two sets of the low-voltage side winding A, the power interface of one set of the low-voltage side winding A1 is connected to the grid-side converter of the converter through the low-voltage side switch, and the other set of the low-voltage side The power interface of the winding A2 is connected to the stator winding of the doubly-fed generator through the low-voltage side switch 2 and the grid-connected switch.

In the wind power generating set of the present utility model, the voltage rating of the low-voltage side winding A2 is higher than the voltage rating of the low-voltage side winding A1; the power interface of the low-voltage side winding A passes through the current protection device through the low-voltage side switch connected to the grid-side converter of the converter.

In the wind power generating set of the present utility model, the generator is a synchronous generator or an asynchronous generator; the transformer includes a set of the low-voltage side winding A, and the power interface of the low-voltage side winding A passes through the low-voltage side switch The protection device is connected to the grid-side converter of the converter, and the generator-side converter of the converter is connected to the stator of the generator.

In the wind power generating set of the present utility model, the generator is a synchronous generator or an asynchronous generator; the transformer includes at least two sets of the low-voltage side windings A, and the converter includes a The same number of grid-side converters as the winding A; the low-voltage side winding A of the transformer is connected to the grid-side converters of the converter in one-to-one correspondence.

In the wind power generating set of the present utility model, the grid-side converter of the converter is connected to the DC side of the machine-side converter after being connected in series or in parallel on the DC side.

In the wind power generating set of the present utility model, the low-voltage side winding B also provides a power interface for supplying power to internal devices of the wind power generating set.

In the wind power generating set of the present utility model, the per unit value of the leakage inductance of the low voltage side of the transformer is greater than or equal to the per unit value of the leakage inductance of the high voltage side.

In the wind power generating set of the present utility model, the transformer and the converter are installed in layers in the tower; or the transformer and the converter are installed in layers or in the same layer Inside the cabinet.

In the wind power generating set of the present utility model, the low-voltage side switch is arranged in the converter or in the transformer; the voltage sampling circuit is a voltage transformer, a voltage hall sensor, a resistance voltage divider circuit Or a linear optocoupler.

Implement the wind power generation unit of the present utility model, compare with prior art, its beneficial effect is:

1. Integrate the transformer and converter circuit of the wind power generating set, and make full use of the leakage inductance of the winding on the low-voltage side of the transformer to realize the filtering of the AC side of the converter on the grid side of the converter, without setting the filter circuit of the converter, and reducing the low-voltage side. The number of switches used reduces the circuit cost of the wind turbine;

2. The transformer and converter of the wind turbine are installed together in the tower or the cabinet, which shortens the connection distance between the transformer and the converter, greatly reduces the amount of high-current cables required for installation, and reduces wind power generation. Unit construction costs.

Description of drawings

Fig. 1 is a schematic diagram of the system composition of an existing doubly-fed wind power generating set.

Fig. 2 is a schematic diagram of the system composition of an existing full-power wind power generating set.

Fig. 3 is a schematic diagram of the basic composition of the wind power generating set of the present utility model.

Fig. 4 is a schematic diagram of the system composition of Embodiment 1 of the wind power generating set of the present utility model (double-fed type).

Fig. 5 is a schematic diagram of the system composition of Embodiment 2 of the wind power generating set of the present invention (double-fed type).

Fig. 6 is a schematic diagram of the system composition of Embodiment 3 of the wind power generating set of the present utility model (full power type).

Fig. 7 is a schematic diagram of the system composition of Embodiment 4 of the wind power generating set of the present utility model (full power type).

Fig. 8 is a schematic diagram of the system composition of Embodiment 5 of the wind power generating set of the present utility model (full power type).

detailed description

The utility model will be further described below in conjunction with accompanying drawing and embodiment:

As shown in FIG. 3 , the wind power generating set of the present invention includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence.

The converter includes a controller, a grid-side converter and a machine-side converter. The grid-side converter and the generator-side converter are connected through a DC bus, and are respectively connected to the controller for control. The grid-side converter is electrically connected to the transformer, and the machine-side converter is electrically connected to the generator.

The generator is mechanically connected to the wind turbine, and the wind turbine is mounted on the top of the tower.

The high-voltage side winding of the transformer is connected to the external grid through a high-voltage side switch. The low-voltage side winding of the transformer includes a low-voltage side winding A and a low-voltage side winding B. The low-voltage side winding A provides a power interface, and the low-voltage side winding B provides a signal interface. When designing, ensure that the leakage inductance per unit value of the low-voltage side winding A is greater than or equal to 5%, and the power interface of the low-voltage side winding A is connected to the grid-side converter through the low-voltage side switch. The low-voltage side winding B is connected to the controller through its signal interface.

The converter includes a voltage sampling circuit, which is set on the signal interface of the low-voltage side winding B and connected to the controller.

A voltage sampling circuit is a component for obtaining voltage information, including but not limited to a voltage transformer, a voltage Hall sensor, a resistor divider circuit or a linear optocoupler.

In other embodiments, the low-voltage side winding B may not be provided, and the voltage sampling circuit of the transformer is provided on the high-voltage side winding of the transformer and connected to the controller.

Embodiment one

As shown in Fig. 4, the wind power generating set of the present invention includes a transformer, a converter, a doubly-fed generator, a wind turbine and a tower (not shown in the figure) connected in sequence. in:

The converter includes a controller, a low-voltage side switch, a contactor, a fuse, a grid-side converter and a machine-side converter connected through a DC bus. The grid-side converter of the converter is electrically connected to the transformer through fuses and low-voltage side switches, and the machine-side converter of the converter is electrically connected to the rotor winding of the doubly-fed generator. The stator winding of the double-fed generator is electrically connected to the transformer through a contactor and a low-voltage side switch, and the rotor of the double-fed generator is mechanically connected to the wind turbine. A wind turbine consists of blades and a gearbox mounted on top of a tower. Among them, grid-connected switches such as contactors, thyristors, and circuit breakers can be interchanged, and overcurrent protection devices such as fuses and circuit breakers can be interchanged.

In other embodiments, overcurrent protection devices such as fuses are not provided, and the grid-side converter of the converter is directly electrically connected to the transformer through a low-voltage side switch, which does not affect the realization of the basic purpose of the utility model.

In this embodiment, the transformer includes a high-voltage side winding and three types of low-voltage side windings, wherein the high-voltage side winding is connected to an external power grid through a high-voltage side switch. Among the three types of low-voltage side windings: low-voltage side winding A provides a power interface, and is connected to the grid-side converter of the converter through a low-voltage side switch; low-voltage side winding B provides a signal interface, and is connected to the controller of the converter through a voltage sampling circuit The third type of low-voltage side winding also uses the low-voltage side winding A to provide power interface, which is specially used to supply power to the internal equipment of the wind turbine.

In other embodiments, the transformer may not be provided with the third-type low-voltage side winding; the internal equipment of the wind power generating set may be powered by other means, for example, powered by a storage battery.

The voltage level of the high-voltage side winding of the transformer is set according to the needs of the wind turbine. For example, the voltage of the high-voltage side winding of the transformer can be set at 10kV, and the voltage level of various low-voltage side windings can be set at 690V.

In order to reduce the amount of high-current cables used in the installation of transformers and converters, the transformers and converters can be integrated and installed in the same cabinet in a layered arrangement or the same layer arrangement to reduce installation costs.

The low-voltage side winding A of the transformer is connected to the grid-side converter of the converter, and only one level of low-voltage side switch is required to save power distribution costs. At the same time, the leakage inductance corresponding to the low-voltage side winding A of the transformer can be designed higher, for example, its corresponding inductance per unit value can be set above 5%, so that the grid-side converter of the converter can use the low-voltage The power interface and leakage inductance of the side winding realize AC-DC energy conversion and grid-side current filtering, without setting the original independent filter (including filter inductor and filter capacitor).

When the grid-side converter uses the leakage inductance corresponding to the low-voltage side winding of the transformer as its filter inductance for AC-DC energy conversion, the grid-side converter must collect the grid voltage close to the grid side before the leakage inductance in control to realize The methods include: 1. Setting the voltage sampling circuit on the high-voltage side winding of the transformer (at this time, the low-voltage side winding B may not be installed); 2. Setting the voltage sampling circuit on the signal interface of the low-voltage side winding B of the transformer. The voltage sampling circuit is connected with the controller.

In this embodiment, the low-voltage side winding B and the third-type low-voltage side winding can also be shared, that is, the third-type low-voltage side winding is not provided, and the output of the low-voltage side winding B is used to supply power to the internal equipment of the wind turbine.

Embodiment two

As shown in FIG. 5 , the wind power generating set of this embodiment includes a transformer, a converter, a doubly-fed generator, a wind turbine and a tower (not shown in the figure) connected in sequence. in:

The converter includes a controller, a contactor, and a grid-side converter and a machine-side converter connected through a DC bus. The grid-side converter of the converter is electrically connected to the transformer through the low-voltage side switch II, and the machine-side converter of the converter is electrically connected to the rotor winding of the double-fed generator; the stator winding of the double-fed generator is connected through the contactor and the low-voltage side The switch I is electrically connected to the transformer; the rotor of the doubly-fed generator is mechanically connected to the wind turbine; the wind turbine includes blades and a gearbox, and is installed on the top of the tower.

In this embodiment, the transformer includes high-voltage side windings, two types of low-voltage side windings, low-voltage side winding A and low-voltage side winding B, and low-voltage side switch I and low-voltage side switch II corresponding to low-voltage side winding A. Among them, the high-voltage side winding is connected to the external power grid through the high-voltage side switch; the low-voltage side winding A includes two sets of windings that provide power interfaces, the first set of low-voltage side winding A1 outputs voltage level 1, and is connected to the converter through the low-voltage side switch II The grid-side converter of the second set of low-voltage side winding A2 is connected to the stator winding of the doubly-fed generator through the low-voltage side switch I and contactor. The low-voltage side winding B provides a signal interface and a power interface. On the one hand, it provides a signal interface to connect with the controller of the converter; on the other hand, it provides a power interface to supply power to the internal equipment of the wind turbine.

As an example, according to the needs of wind turbines, the voltage level of the high-voltage side winding of the transformer can be set at 35kV, the voltage level of the first set of low-voltage side winding A1 can be set at 690V, and the voltage level of the second set of low-voltage side winding A2 can be set at 3000V, the voltage level of the low-voltage side winding B can be set at 690V. Here, since the second set of low-voltage side winding A2 is connected to the stator winding of the doubly-fed generator, it does not need to pass through the grid-side converter and the machine-side converter of the converter, which are relatively sensitive to the voltage level, so its voltage level can be set as The voltage level of the first set of low-voltage side winding A1 is higher, thereby reducing the current of the stator branch of the doubly-fed generator, as well as the current level of the corresponding contactor and low-voltage side switch I, and improving the economy of the system.

Since the physical distance between the transformer and the converter is relatively close, they can be installed in the tower at the same time in a layered arrangement to save installation costs.

The first low-voltage side winding A1 of the transformer is connected to the grid-side converter of the converter, and only one low-voltage side switch II needs to be set in between. The second low-voltage side winding A2 of the transformer is connected to the stator winding of the double-fed generator, and there is Only one level of low-voltage side switch I needs to be set, which saves the cost of power distribution.

At the same time, the leakage inductance corresponding to the first set of low-voltage side winding A1 of the transformer is designed to be relatively high, for example, the per unit value of its corresponding inductive reactance is set above 5%. In this way, the grid-side converter of the converter can use the power interface and leakage inductance of the low-voltage side winding to realize AC-DC energy conversion and grid-side current filtering, without setting up independent filters (including filter inductors and filter capacitors).

When the grid-side converter uses the leakage inductance corresponding to the low-voltage side winding of the transformer as its filter inductance for AC-DC energy conversion, the grid-side converter must collect the grid voltage close to the grid side before the leakage inductance in control to realize The methods include: 1. Setting the voltage sampling circuit on the high-voltage side winding of the transformer (in this case, the low-voltage side winding B may not be installed); 2. Setting the voltage sampling circuit on the signal interface of the low-voltage side winding B of the transformer. The voltage sampling circuit is connected with the controller, and the controller implements voltage sampling and control of the grid-side converter.

Embodiment Three

As shown in FIG. 6 , the wind power generating set of this embodiment includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence. in:

The converter includes a controller, a low-voltage side switch, a grid-side converter and a generator-side converter connected through a DC bus. The grid-side converter of the converter is electrically connected to the transformer through the low-voltage side switch, and the machine-side converter of the converter is electrically connected to the stator winding of the generator; the generator is a synchronous or asynchronous generator, and its rotor is mechanically connected to the wind turbine ; The wind turbine includes blades installed on the top of the tower.

In this embodiment, the transformer includes a high-voltage side winding and two types of low-voltage side windings. Among them, the high-voltage side winding is connected to the external power grid through the high-voltage side switch; the low-voltage side winding A provides a power interface, and is connected to the grid-side converter of the converter through the low-voltage side switch; the low-voltage side winding B provides signal interface and power interface, On the one hand, it provides a signal interface to connect with the controller of the converter; on the other hand, it provides a power interface to supply power to the internal equipment of the wind turbine.

As an example, according to the needs of the wind power generating set, the voltage level of the high-voltage side winding of the transformer can be set at 10kV, and the voltage level of various low-voltage side windings can be set at 690V.

Due to the close physical distance between the transformer and the converter, they can be integrated and installed (arranged on the same floor or layered) in the same cabinet to save installation costs.

The low-voltage side winding A of the transformer is connected to the grid-side converter of the converter, and only one low-voltage switch needs to be set between them to save power distribution costs. At the same time, the leakage inductance corresponding to the low-voltage side winding A of the transformer is designed to be relatively high, for example, the per unit value of its corresponding inductive reactance is set above 5%. In this way, the grid-side converter of the converter can use the power interface and leakage inductance of the low-voltage side winding to realize AC-DC energy conversion and grid-side current filtering without setting up independent filters (including filter inductors and filter capacitors).

When the grid-side converter uses the leakage inductance corresponding to the low-voltage side winding of the transformer as its filter inductance for AC-DC energy conversion, the grid-side converter must collect the grid voltage close to the grid side before the leakage inductance in control to realize The methods include: 1. Setting the voltage sampling circuit on the high-voltage side winding of the transformer (in this case, the low-voltage side winding B may not be installed); 2. Setting the voltage sampling circuit on the signal interface of the low-voltage side winding B of the transformer. The voltage sampling circuit is connected with the controller, and the controller implements voltage sampling and control of the grid-side converter.

Embodiment four

As shown in FIG. 7 , the wind power generating set of this embodiment includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence. in:

The converter includes a controller and two grid-side converters and two machine-side converters connected through the DC bus. and the low-voltage side switch II are electrically connected to the transformer; the two machine-side converters of the converter are connected in parallel on the DC side and the AC side, and the AC side is electrically connected to the stator winding of the generator; the generator is a synchronous or asynchronous generator, and its rotor Mechanically connected to the wind turbine; the wind turbine includes blades mounted on top of the tower.

In other embodiments, the number of grid-side converters and generator-side converters of the converter are equal and multiple, and the connection methods are also as described above.

In this embodiment, the transformer includes a high-voltage side winding, two types of low-voltage side windings (low-voltage side winding A and low-voltage side winding B), and a low-voltage side switch corresponding to the low-voltage side winding A. Among them, the high-voltage side winding is connected to the external power grid through the high-voltage side switch; the low-voltage side winding A includes two sets of windings that provide power interfaces, and their output voltage levels are equivalent, and are connected to the two converters through the low-voltage side switches I and II respectively. The grid-side converter is connected; the low-voltage side winding B provides a signal interface and is connected to the controller of the converter.

As an example, according to the needs of the wind power generating set, the voltage level of the high-voltage side winding of the transformer can be set at 20kV, and the voltage level of various low-voltage side windings can be set at 690V.

Since the physical distance between the transformer and the converter is relatively close, they can be installed in the tower at the same time in a layered arrangement to save installation costs.

The low-voltage side winding A of the transformer is connected to the grid-side converter of the converter, and only one low-voltage side switch is required to save power distribution costs. At the same time, design the leakage inductance corresponding to the low-voltage side winding A of the transformer to be relatively high, for example, set its corresponding inductance per unit value above 5%, so that the grid-side converter of the converter can use the low-voltage side The power interface and leakage inductance of the winding realize AC-DC energy conversion and grid-side current filtering, without setting an independent filter.

When the grid-side converter uses the leakage inductance corresponding to the low-voltage side winding of the transformer as its filter inductance for AC-DC energy conversion, the grid-side converter must collect the grid voltage close to the grid side before the leakage inductance in control to realize The methods include: 1. Setting the voltage sampling circuit on the high-voltage side winding of the transformer (in this case, the low-voltage side winding B may not be installed); 2. Setting the voltage sampling circuit on the signal interface of the low-voltage side winding B of the transformer. The voltage sampling circuit is connected with the controller, and the controller implements voltage sampling and control of the grid-side converter.

In this implementation, the two grid-side converters of the converter can use the same modulation signal and a carrier signal with a phase difference of 180 degrees to drive their power semiconductor devices, so that the two sets of low-voltage side windings in the transformer can be used The leakage inductance between A realizes the internal cancellation of the switching ripple current and improves the grid-connected power quality.

Embodiment five

As shown in FIG. 8 , the wind power generating set of this embodiment includes a transformer, a converter, a generator, a wind turbine and a tower (not shown in the figure) connected in sequence. in:

The converter includes a controller, two grid-side converters and a generator-side converter connected through a DC bus. The two grid-side converters of the converter are connected in series on the DC side, and the AC side is electrically connected to the transformer through low-voltage side switches I and II respectively. One end of the machine-side converter of the converter is electrically connected to the DC bus bar after the DC side of the two grid-side converters is connected in series, and the other end is electrically connected to the stator winding of the generator. The generator is a synchronous or asynchronous generator, and its rotor is mechanically connected with the wind turbine; the wind turbine includes blades installed on the top of the tower.

In other embodiments, the number of grid-side converters of the converter can be more than two, and the number of generator-side converters can also be two or more. The grid-side converters are connected in series and then connected to the generator-side converters.

In this embodiment, the transformer includes a high-voltage side winding, two types of low-voltage side windings (low-voltage side winding A and low-voltage side winding B), and low-voltage side switches I and II corresponding to the low-voltage side winding A. Among them, the high-voltage side winding is connected to the external power grid through the high-voltage side switch; the low-voltage side winding A includes two sets of windings that provide power interfaces, and their output voltage levels are equivalent, and are connected to the two converters through the low-voltage side switches I and II respectively. connected to the grid-side converter. The low-voltage side winding B provides a signal interface and is connected to the controller of the converter, and on the other hand provides a power interface to supply power to the internal equipment of the wind turbine.

As an example, according to the needs of wind turbines, the voltage level of the high-voltage side winding of the transformer can be set at 35kV, the voltage level of the low-voltage side winding A can be set at 3000V, and the voltage level of the low-voltage side winding B can be set at 100V.

Due to the close physical distance between the transformer and the converter, they can be installed in the same cabinet at the same time or in layers to save installation costs. The low-voltage side winding A of the transformer is connected to the grid-side converter of the converter, and only one low-voltage side switch is required to save power distribution costs. At the same time, design the leakage inductance corresponding to the low-voltage side winding A of the transformer to be relatively high, for example, set its corresponding inductance per unit value above 5%, so that the grid-side converter of the converter can use the low-voltage side The power interface and leakage inductance of the winding realize AC-DC energy conversion and grid-side current filtering, without setting an independent filter.

When the grid-side converter uses the leakage inductance corresponding to the low-voltage side winding of the transformer as its filter inductance for AC-DC energy conversion, the grid-side converter must collect the grid voltage close to the grid side before the leakage inductance in control to realize The methods include: 1. Setting the voltage sampling circuit on the high-voltage side winding of the transformer (in this case, the low-voltage side winding B may not be installed); 2. Setting the voltage sampling circuit on the signal interface of the low-voltage side winding B of the transformer. The voltage sampling circuit is connected with the controller, and the controller implements voltage sampling and control of the grid-side converter.

In this implementation, the two grid-side converters of the converter in this implementation can use the same modulation signal and a carrier signal with a phase difference of 180 degrees to drive their power semiconductor devices, so that two sets of The leakage inductance between windings A on the low-voltage side realizes the internal cancellation of the switching ripple current and improves the grid-connected power quality.

Claims (10)

1. A wind power generating set, comprising a transformer, a converter, a generator, a wind turbine and a tower connected in sequence; the converter includes a controller, a grid side connected to the controller and connected through a DC bus converter and machine-side converter, the grid-side converter is electrically connected to the transformer, the machine-side converter is electrically connected to the generator, the generator is mechanically connected to the wind turbine, and the wind turbine is installed on the top of the tower , the high-voltage side winding of the transformer is connected to the external power grid through the high-voltage side switch; It is characterized in that the low-voltage side winding of the transformer includes at least one set of low-voltage side windings A that provide power interfaces, the leakage inductance per unit value corresponding to each of the low-voltage side windings A is greater than or equal to 5%, and through its power interface through the low-voltage side A switch is connected to the grid-side converter; The converter includes a voltage sampling circuit connected to the controller; the voltage sampling circuit is arranged on the high-voltage side winding of the transformer, or the low-voltage side winding of the transformer includes at least one set of low-voltage side winding B that provides a signal interface, The voltage sampling circuit is arranged on the signal interface of the low-voltage side winding B. 2. The wind power generating set according to claim 1, wherein the generator is a doubly-fed generator; The transformer includes a set of the low-voltage side winding A, the power interface of the low-voltage side winding A is connected to the grid-side converter of the converter through a low-voltage side switch, and connected to the doubly-fed generator through a grid-connected switch the stator winding; Or the transformer includes two sets of the low-voltage side winding A, the power interface of one set of the low-voltage side winding A1 is connected to the grid-side converter of the converter through the low-voltage side switch, and the other set of the low-voltage side The power interface of the winding A2 is connected to the stator winding of the doubly-fed generator through the low-voltage side switch 2 and the grid-connected switch. 3. The wind power generating set according to claim 2, wherein the voltage rating of the low-voltage side winding A2 is higher than the voltage rating of the low-voltage side winding A1; the power interface of the low-voltage side winding A passes through The low-voltage side switch is connected to the grid-side converter of the converter through the current protection device. 4. The wind power generating set according to claim 1, wherein the generator is a synchronous generator or an asynchronous generator; the transformer includes a set of the low-voltage side winding A, and the power of the low-voltage side winding A The interface is connected to the grid-side converter of the converter through the low-voltage side switch through the current protection device, and the machine-side converter of the converter is connected to the stator of the generator. 5. The wind power generating set according to claim 1, wherein the generator is a synchronous generator or an asynchronous generator; the transformer includes at least two sets of the low-voltage side windings A, and the converter includes The same number of grid-side converters as the low-voltage side winding A of the transformer; the low-voltage side winding A of the transformer is connected to the grid-side converters of the converter in one-to-one correspondence. 6 . The wind power generating set according to claim 5 , wherein the grid-side converter of the converter is connected to the DC side of the machine-side converter after being connected in series or in parallel on the DC side. 6 . 7. The wind power generating set according to any one of claims 1 to 6, wherein the low-voltage side winding B also provides a power interface for supplying power to internal devices of the wind power generating set. 8. The wind power generating set according to any one of claims 1 to 6, wherein the per unit value of the leakage inductance of the low voltage side of the transformer is greater than or equal to the per unit value of the leakage inductance of the high voltage side. 9. The wind power generating set according to any one of claims 1 to 6, wherein the transformer and the converter are installed in layers in the tower; or the transformer and the converter The devices are arranged in layers or in the same layer and installed in a cabinet. 10. The wind power generating set according to any one of claims 1 to 6, wherein the low-voltage side switch is set in the converter or in the transformer; the voltage sampling circuit is a voltage mutual inductance device, voltage hall sensor, resistor divider circuit or linear optocoupler.