Induction type phase-change power supply rotating exciter device and method

Abstract

In order to improve the stability of an existing exciter, a three-phase input winding is arranged on a stator and is connected with a three-phase power supply, a rotor is coaxially connected with a main generator, and meanwhile, a multi-phase output winding is arranged on the rotor and is connected with the input end of a rotating rectifier; the rotor is driven by a prime motor to rotate, and the rotating direction of the rotor is opposite to the rotating magnetic field direction of the stator. When the phase-changing power supply rotor is driven by a prime motor, a rotor winding cuts a stator rotating magnetic field with double fundamental frequency, multi-phase double fundamental frequency induced electromotive force is generated in the rotor winding, and power is supplied to a main generator exciting winding after rectification. The function of converting a three-phase power supply into a multi-phase power supply and then rectifying the multi-phase power supply into a direct-current excitation power supply is achieved, the reliability is high, and brushless can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of phase-changing power supply, and in particular to an induction-type phase-changing power supply rotating exciter device and method. Background Art

[0002] With the continuous improvement of power generation technology and equipment manufacturing level, the capacity of generators is increasing, and the corresponding excitation current is also increasing. Using multi-phase current to rectify direct current for generator excitation has strong fault tolerance and high excitation power.

[0003] Multiphase power supply allows the rectifier to distribute the load more evenly, reduce harmonics, improve rectification efficiency, and handle greater power. With the same power demand, increasing the number of phases can reduce the current per phase, thereby reducing the risk of overload of the internal components of the rectifier. Due to the reduction in current, the heat loss of the rectifier will also be reduced accordingly, increasing its reliability and service life.

[0004] The use of power electronics technology to achieve phase conversion requires complex rectification and inversion processes, and in order to reduce the impact of harmonics, related filtering devices need to be set up, and their stability and overload capacity are limited. Summary of the invention

[0005] The object of the present invention is to provide an induction type phase-changing power supply rotating exciter and a working method to improve the stability and overload capacity of the exciter.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: An induction type phase-changing power supply rotating exciter comprises: a stator, a rotor and a rotating rectifier, wherein the stator is provided with a three-phase input winding, the phase sequence of the three-phase input winding is set to a clockwise or counterclockwise positive phase sequence (ensuring that the direction of the stator rotating magnetic field is opposite to the rotation direction of the main generator rotor), and the three-phase input winding is connected to a three-phase symmetrical power supply; the rotor is provided with a multi-phase output winding, the rotor where the multi-phase output winding is located is coaxially connected to the main generator, and the output end of the multi-phase output winding is connected to the input end of the rotating rectifier; the rotating rectifier rectifies the multi-phase output voltage generated by the multi-phase output winding into direct current.

[0007] A three-phase power supply regulating device is provided between the three-phase symmetrical power supply and the three-phase input winding, for regulating the magnitude of the input voltage.

[0008] A working method of an induction type phase-changing power supply rotating exciter, comprising the following steps: a. Set a three-phase input winding on the stator, and set the phase sequence of the three-phase input winding to a clockwise or counterclockwise positive phase sequence to ensure that after the stator is connected to a three-phase symmetrical power supply, the direction of the rotating magnetic field generated is opposite to the rotation direction of the generator rotor, and connect the three-phase input winding to the three-phase symmetrical power supply; b. A multi-phase output winding is provided on the rotor, and the rotor is coaxially connected to the main generator rotor, the rotor rotation direction is opposite to the stator rotating magnetic field direction, and the multi-phase output winding is connected to the input terminal of the rotating rectifier; c. A three-phase symmetrical power supply is connected to a three-phase input winding, which generates a three-phase symmetrical current and forms a rotating magnetic field; d. The rotor is coaxially connected to the main generator rotor and is driven by the prime mover to rotate at synchronous speed in the opposite direction of the rotating magnetic field formed in the stator; e. The rotor winding cuts the rotating magnetic field formed by the three-phase input winding at a speed twice the base frequency, and a multi-phase output voltage with a frequency twice the input voltage is generated in the multi-phase output winding; f. The rotating rectifier rectifies the multi-phase output voltage into direct current.

[0009] Preferably, the method further includes controlling the voltage of a given three-phase input winding to control the magnitude of the multi-phase output voltage, thereby controlling the magnitude of the DC excitation current.

[0010] The multi-phase output winding is divided into four-phase, five-phase, six-phase, nine-phase or twelve-phase or any other phase number to meet different application requirements.

[0011] The rotating rectifier is installed coaxially with the rotor of the generator, and the rectified DC power is directly used to provide excitation current for the generator.

[0012] The present invention has the following beneficial effects: 1. Compared with the traditional excitation system, the main exciter and auxiliary exciter are cancelled, the structure is simpler, and the system reliability is improved. At the same time, compared with the fully static power electronic excitation device, the brushes are cancelled, which facilitates the improvement of excitation capacity and stability.

[0013] 2. Generate multi-phase alternating current, and can generate multi-phase electricity with a frequency twice that of the input voltage. The multi-phase current is rectified into direct current, which has strong fault tolerance for the excitation of the generator, and the output DC voltage pulsation obtained after rectification is small.

[0014] 3. Compared with the method of changing the number of power supply phases by power electronics technology, the present invention has improved stability and overload capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the induction type phase-changing power supply rotating exciter of the present invention; Figure 2 It is a flow chart of the induction type phase-changing power supply rotating exciter method of the present invention; Figure 3 The structural diagram of the brushless excitation system composed of the present invention; Figures 1 to 3The reference numerals shown in the figure represent respectively: 1-three-phase input winding; 2-multi-phase output winding; 3-stator; 4-rotor; 5-three-phase power supply regulating device; 6-induction type variable phase power supply rotating exciter; 7-rotating rectifier; 8-generator. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] Example 1 Please refer to Figure 1 The present invention provides an induction type phase-changing power supply rotating exciter, the core part of which includes a stator 3 and a rotor 4, which are connected to each other through a suitable mechanical structure and allow relative rotation. The stator 3 is wound with three-phase input windings 1, which are used to receive a three-phase symmetrical power supply from the outside and form a closed circuit with it. The rotor 4 is wound with multi-phase output windings 2 (twelve phases in this example), which are connected to the input end of the rotating rectifier 7.

[0018] In order to realize the function of the device, the three-phase symmetrical power supply is first regulated by the three-phase power supply regulating device 5 to control its voltage. The regulated power supply is sent to the stator three-phase input winding 1, thereby exciting a three-phase symmetrical current in the winding to form a rotating magnetic field.

[0019] At the same time, the rotor 4 rotates in the opposite direction relative to the stator rotating magnetic field under the action of an external driving force (such as being coaxially installed with the rotor of the generator and driven by the rotation of the generator).

[0020] When the stator rotates, the magnetic field cuts the rotor multi-phase output winding 2, thereby generating a stable multi-phase (twelve-phase) output voltage with a frequency twice that of the input voltage in the multi-phase output winding 2.

[0021] Reference Figure 3 These multi-phase output voltages are then fed into the rotating rectifier 7 and converted into direct current after rectification. Since the rotating rectifier 7 is coaxially mounted with the rotor of the generator 8, the direct current obtained after rectification can be directly supplied to the generator 8 as an excitation current, thereby realizing the excitation function of the generator 8.

[0022] It is worth noting that in this embodiment, the multi-phase output winding 2 is designed to be twelve phases, wherein the angle between the axes of two adjacent phase windings is 30 degrees. Such a design enables the device to output a stable multi-phase voltage, and by adjusting the electrical angle between the winding axes, it can also flexibly output any multi-phase number such as four phases, five phases, six phases, nine phases or twelve phases to meet different application requirements.

[0023] Example 2 Reference Figure 2 , a working method of an induction type phase-changing power supply rotating exciter, comprising the following steps: a. A three-phase input winding 1 is provided on the stator 3, and the phase sequence of the three-phase input winding 1 is set to a clockwise positive phase sequence or a counterclockwise phase sequence (to ensure that the direction of the stator rotating magnetic field is opposite to the direction of the rotor rotation), and the three-phase input winding 1 is connected to a three-phase symmetrical power supply; b. The rotor 4 is provided with a multi-phase output winding 2, the rotor of the multi-phase output winding 2 is coaxially connected to the main generator rotor and rotates synchronously with the main generator rotor, and the multi-phase output winding 2 is connected to the input terminal of the rotating rectifier 7; c. A three-phase symmetrical power supply is connected to the three-phase input winding 1, a three-phase symmetrical current is generated in the three-phase input winding 1, and a clockwise or counterclockwise rotating magnetic field is formed. The rotating magnetic field rotates in the opposite direction to the main generator rotor; d. The rotor 4 is coaxially connected to the main generator rotor and rotates at a synchronous speed with the main generator rotor driven by the prime mover; e. The stator magnetic field is cut by the rotor multiphase winding at twice the base frequency speed, generating a 2-fold frequency induced electromotive force in the rotor multiphase winding 2; f. The rotating rectifier 7 rectifies the multi-phase output voltage into direct current.

[0024] Specifically, it also includes the step of controlling the voltage of a given three-phase input winding 1 to control the magnitude of the multi-phase output voltage, and further controlling the magnitude of the DC excitation current.

[0025] The multi-phase output winding 2 is designed to be any multi-phase number such as four phases, five phases, six phases, nine phases or twelve phases to meet different application requirements. When the multi-phase output winding 2 is designed to be twelve phases, the angle between the axes of two adjacent phase windings is 30°, the rotating rectifier 7 is coaxially installed with the rotor of the generator 8, and the DC power obtained after rectification is directly used to provide excitation current for the generator 8.

[0026] In summary, the induction type phase-changing power supply rotating exciter device of the present invention realizes the conversion of a three-phase symmetrical power supply into a multi-phase output power supply through ingenious structural design and working principle, and the obtained multi-phase output voltage frequency is twice the input voltage frequency, and then rectified into a DC excitation current, thereby realizing brushless operation, small voltage pulsation, simple structure, reliable system and stable output.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An induction type phase-changing power supply rotating exciter, characterized in that: include: A stator (3), a rotor (4) and a rotating rectifier (7), wherein the stator (3) is provided with a three-phase input winding (1), the phase sequence of the three-phase input winding (1) being set to a clockwise positive phase sequence or a reverse phase sequence, and the three-phase input winding (1) being connected to a three-phase symmetrical power supply; the rotor is provided with a multi-phase output winding (2), the rotor of the multi-phase output winding (2) being connected to a main generator rotor and coaxially rotating, the rotation direction of the variable phase power supply rotor being opposite to the rotation direction of the rotating magnetic field formed by the three-phase winding of the variable phase power supply stator passing alternating current, and the multi-phase output winding (2) being connected to the input end of the rotating rectifier (7); the rotating rectifier (7) rectifies the multi-phase output voltage generated by the multi-phase output winding (2) into direct current.

2. The induction type phase-changing power supply rotating exciter according to claim 1, characterized in that: A three-phase power supply regulating device (5) is provided between the three-phase symmetrical power supply and the three-phase input winding (1) for regulating the magnitude of the voltage.

3. A method for operating an induction type phase-changing power supply rotating exciter according to any one of claims 1 to 2, characterized in that: The following steps are involved: a. A three-phase input winding (1) is provided on the stator (3), the phase sequence of the three-phase input winding (1) is set to a clockwise positive phase sequence or a counterclockwise phase sequence, and the three-phase input winding (1) is connected to a three-phase symmetrical power supply; b. A multi-phase output winding (2) is provided on the rotor (4), the rotor of the multi-phase output winding (2) is coaxially connected to the main generator rotor and rotates synchronously with the main generator rotor, and the multi-phase output winding (2) is connected to the input end of the rotating rectifier (7); c. A three-phase symmetrical power supply is connected to the three-phase input winding (1), a three-phase symmetrical current is generated in the three-phase input winding (1), and a clockwise or counterclockwise rotating magnetic field is formed, and the rotating magnetic field rotates in the opposite direction to the main generator rotor; d. The rotor (4) is coaxially connected to the main generator rotor and rotates at a synchronous speed with the main generator rotor under the drive of the prime mover; e. The stator magnetic field is cut by the rotor multiphase winding at twice the base frequency speed, generating a double frequency induced electromotive force in the rotor multiphase winding (2); f. The rotating rectifier (7) rectifies the multi-phase output voltage into direct current.

4. The working method of the induction type phase-changing power supply rotating exciter according to claim 3, characterized in that: The method also includes the step of controlling the voltage of a given three-phase input winding (1) to control the magnitude of the multi-phase output voltage, thereby controlling the magnitude of the DC excitation current.

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