CN201903629U - Alternating current transformation-type excitation synchronous wind power generation experimental facility - Google Patents

Abstract

AC variable voltage excitation synchronous wind power generation experimental device, the three-phase power supply is connected to one end of the air switch, the other end of the air switch is connected to the input terminal RST of the frequency converter, and the output terminal UVW of the frequency converter is connected to the electrical terminal ABC of the AC asynchronous motor. The shaft of the AC asynchronous motor is connected with the shaft of the excitation synchronous generator through a coupling, the electrical output terminal UVW of the excitation synchronous generator is connected with the input terminal ABC of the transformer, and the output terminal abc of the transformer is connected with the input terminal UVW of the rectifier unit connection, the output terminal of the rectifier unit is connected with the input terminal of the active inverter unit, the output terminal UVW of the active inverter unit is connected with the three-phase power supply, and the excitation power supply provides excitation for the excitation synchronous generator. The frequency alternating current is boosted first, then rectified, and then the voltage that meets the inverter requirements is sent to the active inverter unit to complete the grid-connected power generation. It has the characteristics of simple structure and convenient use.

Description

AC variable voltage excitation synchronous wind power generation experimental device

technical field

The utility model belongs to the technical field of wind power generation and relates to a wind power generation experiment device, in particular to an AC variable voltage excitation synchronous wind power generation experiment device.

Background technique

With the increasing shortage of earth's energy and the increasing environmental pollution, wind energy has been paid more and more attention as a renewable green energy, and wind power generation technology has become the focus of research in countries all over the world.

Generally, the available wind speed of wind power generation is 3-20m/s. According to whether the speed of the generator connected to the wind turbine is constant or not, wind power generation can be divided into two modes: constant speed operation and variable speed operation. According to the structure of the generator, it can be roughly divided into three types: AC asynchronous generator, AC synchronous generator and AC double-fed generator. The structure of the AC asynchronous generator is relatively simple, and the power-frequency AC generated can be directly used or input into the power grid through a frequency converter. Motor wind power generation systems generally cannot operate independently of the grid unless they are excited in some way. When the asynchronous wind turbine is connected to the grid, it is connected to the grid through a soft grid-connected device controlled by a thyristor, and is closed and connected to the grid near the synchronous speed, so the inrush current is relatively large, and a capacitive reactive power compensation device needs to be added.

The early synchronous wind power generation system required that the speed of the generator should be constant regardless of the torque of the generator and the resistance torque of the wind turbine, otherwise the generator would be disconnected from the grid. For this reason, the synchronous generator grid-connected system should use a speed regulating mechanism to maintain the generator rotor speed constant, and it needs to perform synchronous and full-step operation. This wind turbine grid-connected system is called a constant speed and constant frequency system. Since the synchronous generator grid-connected system needs to use a speed regulating mechanism, which increases the complexity of the system, when the wind energy fluctuates greatly, the torque acting on the rotor is extremely unstable, and the speed regulating performance of the speed regulating mechanism is difficult to achieve synchronous power generation The speed regulation accuracy required by the machine.

With the advancement of power electronic conversion technology, advanced synchronous wind power generation systems often adopt the AC-DC-AC connection method, that is, first convert the AC output of the synchronous generator into DC, and then invert it into a power frequency AC connection. The advantage of this power generation method is that the generator speed does not have to be synchronized with the speed required by the grid frequency. The structure of the doubly-fed generator is similar to that of a wound-type asynchronous generator, and its feeding method is similar to that of a doubly-fed motor or asynchronous motor supersynchronous cascaded speed regulation system, that is, the stator winding is connected to the grid, and the rotor winding is composed of a set of AC-AC Or the AC-DC-AC converter provides a power supply with adjustable frequency, phase and amplitude to achieve constant frequency output. In order to obtain constant frequency current output, the low-frequency excitation current provided by the converter first forms a rotation in the rotor. Excitation, the sum of the rotation speed of the excitation and the mechanical speed of the rotor is equal to the synchronous speed of the stator magnetic field, so that the power frequency voltage is induced in the stator winding. When the wind speed changes and the rotor speed of the generator changes, the excitation current in the rotor winding is changed. The frequency and the rotational speed of the rotating magnetic field can keep the rotational speed of the stator rotating magnetic field constant, so as to achieve the purpose of variable speed and constant frequency power generation. It can also realize the independent adjustment of the active and reactive power of the generator by adjusting the amplitude and phase of the excitation current. The converter only needs to supply the slip power capacity and does not need to be large, which greatly reduces the capacity of the converter, and the cost and control difficulty of the converter are greatly reduced. Its disadvantage is that the AC excitation generator needs slip rings and brushes.

Contents of the invention

The purpose of this utility model is to provide an AC variable voltage excitation synchronous wind power generation experimental device, which uses a power electronic device-frequency converter to build an excitation synchronous wind power generation experimental system, which has the characteristics of simple structure and convenient use.

In order to achieve the above-mentioned purpose, the technical solution of the utility model is: an AC variable voltage excitation synchronous wind power generation experimental device, including an air switch 2, a three-phase power supply 1 connected to one end of the air switch 2, and the other end of the air switch 2 connected to the frequency converter The input terminal RST of 3 and the output terminal UVW of the frequency converter 3 are connected to the electrical terminal ABC of the AC asynchronous motor 4, the shaft of the AC asynchronous motor 4 is connected with the shaft of the excitation synchronous generator 6 through the coupling 5, and the excitation synchronous generator The electrical output terminal UVW of 6 is connected with the input terminal ABC of the transformer 7, the output terminal abc of the transformer 7 is connected with the input terminal UVW of the rectification unit 8, the output terminal of the rectification unit 8 is connected with the input terminal of the active inverter unit 9 The output terminal UVW of the active inverter unit 9 is connected with the three-phase power supply 10 .

The excitation power supply 11 provides excitation for the excitation synchronous generator 6 .

The excitation synchronous generator 6 is a brushless excitation synchronous generator or a brushed excitation synchronous generator.

The rectification unit 8 is a diode bridge rectification circuit or a rectification circuit of the input part of the frequency converter.

The active inverter unit 9 is a frequency converter with a feedback function, a PWM rectification circuit or an active rectification module.

The excitation synchronous generator 6 is used as a wind power generator and a power electronic device to build a full-power inverter excitation synchronous wind power generation experimental system with a full-power inverter circuit. The non-power frequency alternating current generated by the excitation synchronous generator 6 is first boosted, and then Perform rectification again, and then send the voltage that meets the inverter requirements to the active inverter unit 9 to complete grid-connected power generation. Using a non-power frequency step-up scheme to build a wind power generation experimental system is beneficial to the main structure and system of the wind power generation system. It is beneficial to study and test the working characteristics of wind turbines, and provide an experimental platform for the development, development, and testing of converters and wind power control systems. It has the characteristics of simple structure and easy use.

Description of drawings

Accompanying drawing is the structural representation of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, structural principle and working principle of the present utility model are described in further detail.

The AC transformer excitation synchronous wind power generation experimental device includes an air switch 2, a three-phase power supply 1 connected to one end of the air switch 2, the other end of the air switch 2 connected to the input terminal RST of the frequency converter 3, and the output terminal UVW of the frequency converter 3 Connected to the electrical terminal ABC of the AC asynchronous motor 4, the shaft of the AC asynchronous motor 4 is connected to the shaft of the excitation synchronous generator 6 through the coupling 5, the electrical output terminal UVW of the excitation synchronous generator 6 is connected to the input terminal ABC of the transformer 7 The output terminal abc of the transformer 7 is connected with the input terminal UVW of the rectification unit 8, the output terminal of the rectification unit 8 is connected with the input terminal of the active inverter unit 9, and the output terminal UVW of the active inverter unit 9 is connected with The three-phase power supply 10 is connected in phase.

The excitation power supply 11 provides excitation for the excitation synchronous generator 6 . The excitation synchronous generator 6 is a brushless excitation synchronous generator or a brushed excitation synchronous generator. The rectification unit 8 is a diode bridge rectification circuit or a rectification circuit of the input part of the frequency converter. The active inverter unit 9 is a frequency converter with a feedback function, a PWM rectification circuit or an active rectification module.

The frequency converter 3 and the AC asynchronous motor 4 convert electrical energy into mechanical energy, and make the output mechanical characteristics (torque and speed characteristics) of the AC asynchronous motor 4 shaft consistent with those of the wind turbine shaft.

The excitation synchronous generator 6 starts to run under the drive of the AC asynchronous motor 4 whose rotation speed changes with the wind speed, and the mechanical energy can be converted into electrical energy output by providing a certain excitation current. The frequency of the output voltage of the excitation synchronous generator 6 depends only on the synchronous power generation Therefore, at this time, the synchronous generator sends out non-power frequency AC, and the voltage amplitude also depends on the joint effect of the excitation current and the rotational speed. Therefore, when running at low speed, the voltage amplitude cannot meet the requirements of grid-connected inverter , it must be boosted and rectified before active inverter can be connected to the grid. The utility model is to step up the non-power frequency AC power generated by the excitation synchronous generator 6 first, then rectify it, and then send the voltage meeting the inverter requirements to the active inverter unit 9 to complete grid-connected power generation.

In the utility model, the energy is first transmitted to the frequency converter 3 in the form of electric energy, and then the frequency converter 3 is transmitted to the AC asynchronous motor 4, and the AC asynchronous motor 4 converts the electrical energy into mechanical energy and transmits it to the excitation synchronous generator 6, and the excitation synchronous generator 6. Reconvert the mechanical energy into non-industrial frequency electrical energy, and the frequency converter 3 and power electronic circuit process the non-industrial frequency electrical energy and transmit it back to the grid.

Claims (6)

1. AC variable voltage excitation synchronous wind power generation experimental device, including an air switch (2), characterized in that the three-phase power supply (1) is connected to one end of the air switch (2), and the other end of the air switch (2) is connected to the frequency conversion The input terminal RST of the inverter (3), the output terminal UVW of the frequency converter (3) is connected to the electrical terminal ABC of the AC asynchronous motor (4), and the shaft of the AC asynchronous motor (4) generates electricity synchronously with the excitation through the coupling (5) The shaft of the motor (6) is connected, the electrical output terminal UVW of the excitation synchronous generator (6) is connected with the input terminal ABC of the transformer (7), and the output terminal abc of the transformer (7) is connected with the input terminal of the rectifier unit (8) UVW is connected, the output terminal of the rectification unit (8) is connected with the input terminal of the active inverter unit (9), and the output terminal UVW of the active inverter unit (9) is connected with the three-phase power supply (10). 2. The AC transformer excitation synchronous wind power generation experimental device according to claim 1, characterized in that the excitation power supply (11) provides excitation for the excitation synchronous generator (6). 3. The AC variable voltage type excitation synchronous wind power generation experimental device according to claim 1 or 2, characterized in that, the described excitation synchronous generator (6) is a brushless excitation synchronous generator or a brushed excitation synchronous generator . 4. The AC transformer excitation synchronous wind power generation experimental device according to claim 1, characterized in that the rectification unit (8) is a rectification circuit of a diode bridge rectification circuit or an input part of a frequency converter. 5. AC variable voltage type excitation synchronous wind power generation experimental device according to claim 1, is characterized in that, described active inverter unit (9) is the frequency converter with feedback function, PWM rectifier circuit or active rectification module . 6 . The AC variable voltage excitation synchronous wind power generation experimental device according to claim 1 , wherein wind power generation is realized by adopting non-power frequency step-up.

Images