CN1870385A - Mixing excitation permanent magnetic synchro generator - Google Patents

Abstract

A hybrid excitation permanent magnet synchronous generator belongs to the technical field of electric motors. Including casing, stator core, DC excitation winding, rotor core, rotating shaft, stator armature winding and permanent magnet, the stator core and rotor core are divided into two sections along the axial direction, and the segmented stator cores are respectively connected with the casing. There is a ring-shaped DC excitation winding between the segmented stator cores, and the stator armature winding is a three-phase symmetrical winding, which is respectively placed in the slots of the stator cores of each segment, and a solid magnetic conductor is placed on the rotating shaft between the segmented rotor cores. In the sleeve, permanent magnet blocks and permanent magnet and ferromagnetic pole combination blocks are staggered along the circumference of each section of the rotor core. The magnetic poles of adjacent permanent magnets are opposite in polarity, and the permanent magnets and ferromagnetic poles are arranged at intervals along the axial direction of the two sections of the rotor core, that is Permanent magnet-ferromagnetic pole-permanent magnet, and the magnetic poles of the permanent magnets arranged at intervals have the same polarity. The invention can adjust the ratio of the magnetic pole area occupied by the permanent magnet and the electric excitation, so that the performance of the generator can be optimized.

Description

Hybrid Excitation Permanent Magnet Synchronous Generator

technical field

The invention belongs to the technical field of generators, in particular to a hybrid excitation permanent magnet synchronous generator.

technical background

At present, the structures of permanent magnet synchronous generators mainly include series excitation, shunt excitation and combined hybrid excitation motor structures. Since the permanent magnet generator is excited by permanent magnets, once the motor is made into a magnetic field, it cannot be adjusted, and the voltage generated by the generator will change with the load and temperature changes, so it is difficult to ensure that the voltage is constant when the load is working. G. Hennneberger et al. proposed a motor with a series excitation structure. The electric excitation winding of the motor is placed under the permanent magnet of the rotor and does not need to occupy additional space, so the structure is simple and the volume is small. However, the introduction of the rotor excitation current of this structure adopts a brush type, and the reliability is reduced. In addition, the magnetic circuit of the electric excitation passes through the permanent magnet, and the magnetic permeability of the permanent magnet is close to that of the air, so the magnetic resistance of the magnetic circuit is large. In order to adjust the air gap flux, a large excitation current must be passed in, and the copper loss Increase. At the same time, the magnetomotive force of electric excitation acts directly on the permanent magnet, which is prone to irreversible demagnetization.

A shunt-excited hybrid excitation permanent magnet synchronous generator proposed by Japanese scholars Nobuyuki Naoe and Tadashi Fukami: its structure can be considered as a composite of a general permanent magnet generator and an electric excitation generator. The excitation current on the segmented rotor and the permanent magnets respectively excite their own flux. However, since the excitation current is introduced by the collector ring, the reliability of the motor is reduced, and it is not suitable for operation under harsh working conditions, and the maintenance cost increases. At the same time, if the length of the wound rotor is equal to the length of the permanent magnet rotor, in order to generate a magnetic flux equal to that of the permanent magnet, the excitation current passing through the wound rotor must be relatively large, which will inevitably increase the copper loss of the rotor and increase the temperature rise of the motor. , which leads to problems such as a decrease in efficiency, a change in the operating point of the permanent magnet, and even demagnetization.

Dou Yiping and Chen Haizhen of Nanjing University of Aeronautics and Astronautics proposed a combined hybrid excitation motor structure: the electric excitation auxiliary power generation part and the permanent magnet power generation part share a stator core and stator winding, and the magnetic flux is synthesized in the air gap. The electric excitation uses the rotating shaft as a part of the magnetic circuit, and the structure of the permanent magnet main power generation part is the same as that of the ordinary permanent magnet generator. The motor with this structure can better adjust the output voltage of the generator, has high operation reliability, and has a lower failure rate than a brush structure and a rotary rectifier. However, both sides of the horizontal magnetic pole of the electric excitation part of the generator are air gaps with small lengths, and the processing and assembly precision requirements are very high, which obviously increases the assembly man-hours and manufacturing costs. At the same time, the horizontal magnetic pole and the vertical magnetic pole provide a path for the electric excitation flux, which requires a larger magnetic conduction area, which reduces the power density of the motor. Due to the existence of two additional air gaps, the reluctance of the electrical excitation magnetic circuit of the motor is significantly increased, resulting in a large excitation current and low efficiency of the motor.

Algerian scholar Yacine Amara and others proposed a shunt-excited hybrid excitation motor structure. The stator structure and rotor structure of the motor are too complicated, the manufacturing and assembly costs are significantly increased, and the power density of the motor is not high, the torque fluctuation is large, and the noise is large. , The magnetic flux leakage is serious.

Contents of the invention

Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a hybrid excitation permanent magnet synchronous generator, which can adjust the ratio of the magnetic pole area occupied by the permanent magnet and the electric excitation arbitrarily by changing the distribution structure of the permanent magnet, so as to stabilize the voltage output , high efficiency and low temperature rise.

The structure of the present invention includes a casing, a stator core, a DC excitation winding, a rotor core, a rotating shaft, a stator armature winding and a permanent magnet. The stator core is fixed on the casing along the axial direction of the casing, and the rotor core is placed on the rotating shaft inside the stator core. Above, the stator core and the rotor core are divided into two sections along the axial direction, and the segmented stator cores are respectively connected to the housing, and a ring-shaped DC field winding is placed on the rotating shaft between the segmented stator cores, and the stator armature winding is Three-phase symmetrical windings are respectively placed in the stator core slots of each segment; a solid magnetic sleeve is placed between the segmented rotor cores, and permanent magnet blocks, permanent magnets and ferromagnetic poles are staggered along the circumference of each segment of the rotor core. The magnetic poles of adjacent permanent magnets are opposite in polarity, and the N and S poles of adjacent permanent magnets are staggered from each other, and the staggered angle is less than or equal to one pole pitch. The permanent magnets and ferromagnetic poles are arranged at intervals along the axial direction of the two rotor cores, that is Permanent magnet-ferromagnetic pole-permanent magnet, and the magnetic poles of the permanent magnets arranged at intervals have the same polarity.

The working principle of the present invention: the magnetic field generated by the DC excitation current starts from the ferromagnetic pole, passes through the air gap, the stator, and then passes through the air gap, and finally returns to the adjacent ferromagnetic pole; it has a different magnetic circuit from the permanent magnet flux, but the two The magnetic field is synthesized in the air gap of the generator, and the main flux of the motor can be adjusted by adjusting the field current. When the load is large, the demagnetization effect of the armature reaction is obvious, and the counter electromotive force generated only by the magnetic flux provided by the permanent magnet part is not enough. Therefore, the output voltage through the generator itself is rectified and passed to the DC excitation winding In this process, the air-gap magnetic field is enhanced, so that the output voltage meets the requirements of the load. When the load is small, the demagnetization effect of the armature reaction is not very obvious, so the output voltage will be too large. Therefore, the output voltage of the generator itself is rectified and passed into the DC excitation winding, and can be reversed to weaken the air gap magnetic field, thereby ensuring stable voltage output.

The invention has the advantages of realizing brushless, high reliability, no risk of demagnetization of permanent magnets in the process of electric excitation adjustment, small flux leakage, small electric excitation loss, low temperature rise, high power density and voltage adjustment rate and voltage Low waveform distortion rate. According to different application occasions, the ratio of the magnetic pole area occupied by the permanent magnet and the electric excitation can be adjusted arbitrarily to optimize the performance of the generator. In the two-way regulation process, only a small DC excitation current is needed to regulate the magnetic flux, so that the voltage output is stable, the efficiency is high, and the temperature rise is low.

Description of drawings

Fig. 1 is a structural representation of the present invention,

Fig. 2 is a schematic diagram of the distribution of permanent magnets and ferromagnetic poles on the rotor core of the present invention;

In the figure 1. Housing, 2. Stator core, 3. DC excitation winding, 4. Permanent magnet N pole, 5. Rotor core, 6. Magnetic sleeve, 7. Rotating shaft, 8. Permanent magnet S pole, 9. Stator armature windings, 10. Ferromagnetic poles.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

Embodiment: as shown in Figure 1, the structure of the present invention comprises housing 1, stator iron core 2, DC excitation winding 3, rotor iron core 5, rotating shaft 7, stator armature winding 9 and permanent magnet, and stator iron core 2 is along the casing axis The rotor core 5 is placed on the rotating shaft 7 inside the stator core 2, and is supported by bearings and machine bases. The stator core 2 and the rotor core 5 are divided into two sections along the axial direction, and the segmented stator core 2 is respectively It is connected with the casing 1, and is connected mechanically and electromagnetically through the casing 1. There is an annular DC field winding 3 between the segmented stator cores 2, and the stator armature winding 9 is a three-phase symmetrical winding. Placed in the slots of the stator cores 2 of each segment, a solid magnetic sleeve 6 is placed on the rotating shaft between the segmented rotor cores 5 for the axial magnetic conduction of the rotor. Permanent magnet blocks and permanent magnets and ferromagnetic poles 10 combination blocks, the magnetic poles of adjacent permanent magnets are opposite in polarity, that is, permanent magnet N pole blocks, permanent magnet S poles and ferromagnetic pole 10 combination blocks are arranged at intervals on the circumference of the rotor core 5, And the N and S poles of adjacent permanent magnets are staggered from each other, and the staggered angle is a pole pitch; the permanent magnets and ferromagnetic poles 10 are arranged at intervals along the axial direction of the two rotor cores 5, that is, permanent magnets-ferromagnetic poles-permanent magnets, and are arranged at intervals The polarity of the permanent magnets is the same, and the specific arrangement in this example is: permanent magnet N pole-ferromagnetic pole combination block, permanent magnet N pole, permanent magnet S pole, ferromagnetic pole-permanent magnet S pole combination block, two rows along the Arranged at intervals around the circumference to ensure that the magnetization directions of the permanent magnets under the same coil are the same, forming the hybrid excitation permanent magnet synchronous generator of this example.

Its working principle: the magnetic field generated by the DC excitation current starts from the ferromagnetic pole, passes through the air gap, the stator, and then passes through the air gap, and finally returns to the adjacent ferromagnetic pole; it has a different magnetic circuit from the permanent magnet flux, but the two magnetic fields are in the Synthesized in the air gap of the generator, the main flux of the motor can be adjusted by adjusting the excitation current.

The present invention utilizes the DC excitation winding to adjust the power generation voltage. When the power generation voltage generated by the permanent magnet excitation is lower than the rated voltage during operation, the soft iron magnetic pole and the permanent magnet magnetic pole can be in the same phase by controlling the direction of the current passing through the DC excitation winding. , at this time, the DC excitation winding starts to increase the magnetization; when the voltage generated by the permanent magnet excitation is higher than the rated voltage during operation, the soft iron magnetic pole can be opposite to the permanent magnet magnetic pole by controlling the direction of the current passing through the DC excitation winding. At this time, the DC excitation winding acts as a demagnetizer, so that the magnetic field of the generator can be conveniently adjusted by controlling the magnitude and direction of the current in the DC excitation winding, so that the generator remains constant under load and temperature changes.

Claims (2)

1. A hybrid excitation permanent magnet synchronous generator, including a casing, a stator core, a DC field winding, a rotor core, a rotating shaft, a stator armature winding and a permanent magnet, the stator core is fixed on the casing along the axial direction of the casing, and the rotor The iron core is placed on the rotating shaft inside the stator core. The stator core and the rotor core are divided into two sections along the axial direction. The segmented stator cores are respectively connected to the housing. The excitation winding and the stator armature winding are three-phase symmetrical windings, which are respectively placed in the slots of the stator cores of each segment. A solid magnetic sleeve is placed on the rotating shaft between the segmented rotor cores, and is distributed staggered along the circumference of each segment of the rotor core. There are permanent magnet blocks and permanent magnets and ferromagnetic pole combination blocks. The magnetic poles of adjacent permanent magnets are opposite in polarity. The permanent magnets arranged have the same magnetic polarity. 2. A hybrid excitation permanent magnet synchronous generator according to claim 1, characterized in that the N and S poles of the permanent magnets with opposite polarities adjacent to the two ends of the rotor core are staggered from each other, and the staggered angle is less than or is equal to a polar distance.