Electric and power generation integrated synchronous motor

Abstract

The invention provides an electric and power generation integrated synchronous motor, relates to the technical field of new energy electric power engineering equipment, and solves the limitation problems of insufficient frequency stability and inertia and the like during grid connection of an existing new energy system. The synchronous motor comprises a base, a stator core, a rotor and a rotating shaft, the stator core and the rotating shaft are both mounted on the base, and the rotor sleeves the rotating shaft; a stator winding is arranged on the stator core, the stator winding comprises an electric winding and a power generation winding which are mutually independent, the positions of the electric winding and the power generation winding are correspondingly arranged, and the neutral points of the electric winding and the power generation winding are not connected; the electric winding is connected with the output side of the new energy system, and the power generation winding is connected with the external power grid side. And an excitation winding is arranged on the rotor and is used for generating a main magnetic field under the action of an externally input excitation current. The device integrates electric and power generation functions, has high inertia capability and frequency stability, and also has the advantages of small size and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of new energy power engineering equipment technology, specifically to a synchronous motor that integrates electric motor and generator. Background Technology

[0002] With the deepening of the construction of new power systems, the scale of grid connection of various new energy power generation facilities continues to expand, and a large number of power electronic devices are being connected. While these devices achieve energy conversion, they also bring about a significant increase in the low-frequency and high-frequency harmonic content of the system, resulting in a decline in voltage waveform quality and a general increase in total harmonic distortion. This situation not only poses a potential threat to the safe and economical operation of the power grid, but may also affect the reliability and service life of the new energy power generation equipment itself. In addition, the output of new energy power generation is constrained by natural conditions, exhibiting significant fluctuations and randomness. Its core inverter interface lacks the rotational inertia possessed by traditional thermal power generating units, making it difficult to provide effective inertial support when the power grid encounters frequency disturbances, posing a severe challenge to the system's frequency stability.

[0003] To improve the safety and stability of the power grid under renewable energy integration, existing technologies have proposed using synchronous motor pairs. This approach mainly consists of a physical synchronous motor coupled with a synchronous generator, deployed between the renewable energy inverter and the grid. The aim is to give the renewable energy system operating characteristics similar to traditional thermal power units, thereby enhancing system stability, inertial response capability, and dispatch flexibility. However, this approach relies on at least two physical rotating motors, resulting in inherent limitations such as high system cost, complex manufacturing processes, and strict requirements for installation site layout. Another approach is to develop virtual synchronous motor technology. Its core is to apply the mathematical model and operational control strategy of a synchronous motor to the grid-connected inverter of the renewable energy system. Through corresponding control algorithms, the power electronic converter simulates the inertia and frequency regulation characteristics of a rotating motor, effectively improving the inertia support and frequency stability of the renewable energy power generation system. However, this technical route relies on complex real-time calculations and control, resulting in a relatively slow dynamic response speed and a long adjustment process, making it inadequate in dealing with rapid and severe grid disturbances.

[0004] Further research has explored the structure of an axial flux permanent magnet motor integrating electric and power generation. This design places the stator for electric operation and the stator for power generation in two separate, interconnected housings, relying on a coaxially rotating permanent magnet rotor to achieve bidirectional energy conversion. While this integrated design has unique advantages, it also has significant drawbacks: the excitation magnetic field established by the permanent magnets cannot be flexibly adjusted according to system needs, resulting in relatively weak reactive power output capability, i.e., reactive power support capability, making it difficult to meet the grid's demand for dynamic reactive power compensation. Furthermore, limited by the current technical performance of permanent magnet materials, achieving large-capacity motors presents significant challenges, and increasing their power rating faces bottlenecks. Summary of the Invention

[0005] The purpose of this invention is to address the limitations of existing new energy systems, such as insufficient frequency stability and inertia during grid connection, as well as the complex mechanical structure and high site requirements of coaxially connected synchronous motor pairs. Therefore, this invention proposes an integrated synchronous motor for both motoring and power generation. Through its structural design, the synchronous motor of this invention integrates both motoring and power generation functions, possessing not only the high inertia and frequency stability of synchronous motor pairs, but also the advantages of small size and high efficiency.

[0006] The present invention employs the following technical solutions to achieve its objective: An integrated synchronous motor for both electric and power generation includes a frame, a stator core, a rotor, and a shaft. The stator core and the shaft are both mounted on the frame, and the rotor is mounted on the shaft. The stator core has stator windings, each including an independent electric winding and a power generation winding. The electric winding and the power generation winding are positioned correspondingly, and their neutral points are not connected. The electric winding is connected to the output side of a new energy system, and the power generation winding is connected to the external power grid. The rotor has an excitation winding used to generate a main magnetic field under the action of an externally input excitation current.

[0007] Specifically, the electric winding and the generator winding divide the stator core into an electric core region and a generator core region; there is an electric air gap between the rotor and the electric core region, and there is a generator air gap between the rotor and the generator core region.

[0008] Preferably, the shaft is also fitted with a flywheel via a key, spline, or interference fit.

[0009] Optionally, the synchronous motor can be constructed using a radial flux structure or an axial flux structure.

[0010] Specifically, in the radial flux structure, both the electric winding and the generator winding are composed of three phases, with each phase of the electric winding or the generator winding spatially distributed at an electrical angle of 120 degrees. The coils of each phase of the electric winding or the generator winding are connected by wires to form a closed loop, which is evenly distributed on the stator core. The stator core has a ring structure and surrounds the inner side of the frame of the synchronous motor.

[0011] Specifically, in the radial flux structure, the rotor is located at the center of the stator core, and the excitation windings are respectively surrounding both ends of the rotor, forming the two magnetic poles of the rotor.

[0012] Specifically, in the axial flux structure, the stator core is composed of multiple cylindrical cores evenly arranged along the circumference, and each cylindrical core is surrounded by the electric winding and the generator winding.

[0013] Specifically, in the axial flux structure, the rotor is located on the same side of the plurality of cylindrical iron cores, and the diameter of the rotor is adapted to the diameter of the circumferential structure formed by the arrangement of the plurality of cylindrical iron cores; the excitation winding is provided on the surface of the rotor near the cylindrical iron core, and the coils of the excitation winding are connected by wires to form a closed loop, and the position of the coils of the excitation winding corresponds to the position of the circumferential structure formed by the arrangement of the plurality of cylindrical iron cores.

[0014] Furthermore, the rotor is used to rotate itself and reach synchronous speed through an external starting device after the excitation winding generates the main magnetic field; The electric winding is used to connect to the output side of the new energy system after the rotor reaches synchronous speed; The rotor is also used to disconnect the external starting device after the electric winding is connected to the output side of the new energy system, and maintain its own rotation at a synchronous speed under the voltage action of the output side of the new energy system. The generator winding is used to induce a three-phase AC electromotive force in its own coil when the rotor maintains synchronous speed under the voltage action of the output side of the new energy system, forming AC power and then connecting it to the external power grid after synchronization, so that the synchronous motor completes the power transfer from the output side of the new energy system to the external power grid. The rotor is also used to provide an inertial response for the power transfer process by absorbing excess electrical energy to accelerate rotation or releasing its own rotational kinetic energy to decelerate when the frequency of the output side of the new energy system or the external power grid changes.

[0015] Preferably, the synchronous motor is further configured with a controller for suppressing system power oscillations. The controller includes a power system stabilizer and an automatic voltage regulator. The power system stabilizer is configured to receive input signals corresponding to the synchronous motor in its operating state, the input signals including speed, frequency, and / or output power. The power system stabilizer generates an additional control signal for enhancing system damping based on the input signals and outputs it to the automatic voltage regulator. The automatic voltage regulator adjusts the excitation current applied to the excitation winding according to the additional control signal, enabling the synchronous motor to operate under over-excitation or under-excitation.

[0016] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows: This invention integrates the electric winding and the generator winding into the same stator core, enabling a single synchronous motor to simultaneously possess the dual functions of efficient electric drive and stable power generation. This design not only significantly simplifies the mechanical structural complexity of traditional coaxial synchronous motors but also substantially reduces equipment space requirements and installation and maintenance costs, providing greater flexibility for system integration.

[0017] Compared to virtual synchronous motor solutions that rely on power electronic conversion, the synchronous motor of this invention, with its inherent mechanical rotational inertia, can provide a faster dynamic response to grid fluctuations and effectively smooth out frequency abrupt changes. This natural physical inertia enhances grid friendliness and significantly improves system stability under load abrupt changes or fault disturbances, providing a foundation for grid frequency security.

[0018] The key to this invention is the replacement of traditional permanent magnet excitation with electrical excitation technology. On one hand, the electrical excitation design overcomes the physical limitations of permanent magnet materials on motor capacity, enabling higher power density output. On the other hand, the unique strong excitation capability of electrical excitation can rapidly inject strong excitation current when the grid voltage drops sharply, providing powerful dynamic reactive power support to the system and effectively preventing voltage collapse. Simultaneously, by adjusting the excitation current in real time, the magnitude and direction of reactive power output can be precisely controlled, achieving active and stable regulation of the system voltage and completely overcoming the inherent limitation of permanent magnet excitation in terms of dynamic adjustment.

[0019] The synchronous motor of this invention can be seamlessly integrated into a power system stabilizer. Through closed-loop control of the excitation system by an automatic voltage regulator, low-frequency oscillations in the power system can be suppressed in real time based on multi-dimensional signals such as speed, frequency, or power, significantly enhancing the system's damping characteristics. This mechanism fundamentally solves the power oscillation risk caused by the integration of new energy sources into the grid, providing a key technical guarantee for the safe operation of large-scale power grids.

[0020] Since the motoring and generating windings share the same magnetic circuit structure, the single excitation current regulation of this invention can act synchronously on both windings. This synergistic effect enables the synchronous motor to maintain a stable reactive power output capability while simultaneously operating in motoring and generating modes, achieving seamless reactive power support in dual-function modes and significantly improving the overall voltage regulation efficiency and operational reliability of the system. Attached Figure Description

[0021] The present invention will be further described in detail with reference to the following figures, which specifically include two figures as follows: Figure 1 This is a schematic diagram of the synchronous motor of the present invention after the radial flux structure is arranged. Figure 2 This is a schematic diagram of the synchronous motor of the present invention after the axial flux structure is arranged.

[0022] The meanings of the markings in the attached diagram are as follows: 1-Electric winding, 2-Generator winding, 3-Stator core, 4-Rotor, 5-Excitation winding, 6-Shaft, 7-Frame. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] Example 1 A synchronous motor integrating electric motor and generator, see below. Figure 1 or Figure 2 The schematic diagram shows the structure, which includes a frame 7, a stator core 3, a rotor 4, and a shaft 6. Both the stator core 3 and the shaft 6 are mounted on the frame 7, and the rotor 4 is mounted on the shaft 6. Key design features include: stator windings arranged on the stator core 3, comprising independent electric winding 1 and generator winding 2, positioned correspondingly, with their neutral points not connected; electric winding 1 connected to the output side of the new energy system, and generator winding 2 connected to the external power grid; and an excitation winding 5 arranged on the rotor 4, used to generate the main magnetic field under the action of an externally input excitation current.

[0026] In this embodiment, the main functions and working principles of the relevant components are as follows: The rotor 4 is used to drive itself to rotate and reach synchronous speed after the main magnetic field is generated by the excitation winding 5.

[0027] The electric winding 1 is used to connect to the output side of the new energy system after the rotor 4 reaches synchronous speed; The rotor 4 is also used to disconnect the external starting device after the electric winding 1 is connected to the output side of the new energy system, and maintain its own rotation at synchronous speed under the voltage action of the output side of the new energy system. The generator winding 2 is used to induce a three-phase AC electromotive force in its own coil when the rotor 4 maintains synchronous speed under the voltage action of the output side of the new energy system, forming AC power and connecting it to the external power grid after synchronization, so that the synchronous motor completes the power transfer from the output side of the new energy system to the external power grid. The rotor 4 is also used to provide inertial response for the power transfer process by absorbing excess electrical energy to accelerate rotation or releasing its own rotational kinetic energy to decelerate when the frequency of the output side of the new energy system or the external power grid changes.

[0028] The key innovation of this embodiment lies in the special design of the stator windings and rotor excitation system. The stator core 3 has two completely independent winding systems: the motor winding 1 and the generator winding 2. These two windings are spatially aligned, meaning that the distribution positions of each phase winding within the stator slots are matched, but they are completely isolated in terms of electrical connection. The neutral points of the motor winding 1 and the generator winding 2 are not interconnected, nor do they form a common node with other neutral points. This independent neutral point design is crucial to ensuring the electrical isolation between the two windings, aiming to block the direct current path between the motor and generator sides, preventing energy feedback interference or harmonic crosstalk due to shared neutral points, thereby ensuring the independent controllability of energy transfer.

[0029] The motor winding 1 is specifically designed to connect to the output side of a new energy system, such as the AC bus of a photovoltaic inverter or wind power converter; while the generator winding is directly connected to the external power grid. An excitation winding 5 is arranged on the rotor 4. This winding receives DC current from an external excitation power supply to establish a controllable main magnetic field. The use of the excitation winding 5 is the core technology for achieving flexible magnetic field adjustment in this embodiment of the synchronous motor. Compared to permanent magnet solutions, its magnetic field strength can be adjusted in real time by the excitation current, providing a key degree of control freedom to cope with load fluctuations and frequency changes. Furthermore, in addition to having the excitation winding 5, the rotor 4 itself can also be made of permanent magnet materials.

[0030] When the synchronous motor starts, it requires an external starting device to drive the rotor 4 to rotate. Once the rotor 4 reaches the synchronous speed, the motor winding 1 is connected to the output network of the new energy system. At this time, the three-phase AC voltage output by the new energy system acts on the motor winding 1, forming a rotating magnetic field in the stator space. Since the rotor 4 is already at the synchronous speed and the excitation winding 5 has established the main magnetic field, the interaction between the stator and rotor magnetic fields generates synchronous electromagnetic torque, allowing the rotor 4 to maintain the synchronous speed without mechanical drive. At this time, the external starting device can be disconnected, and the system enters a self-sustaining operation state. The continuous rotation of the rotor 4 causes the main magnetic field generated by the excitation winding to continuously cut the coil conductor of the generator winding 2, inducing a three-phase AC electromotive force with a fixed phase relationship in the generator winding according to the law of electromagnetic induction. When the amplitude, frequency, and phase of this electromotive force match the external grid parameters, the generator winding 2 can be connected to the grid through synchronous control, realizing the transmission of electrical energy from the new energy system to the grid side.

[0031] In this embodiment, it should be noted that although the electric winding 1 and the generator winding 2 share the same set of stator core magnetic circuits and can transfer energy through magnetic flux coupling, they are still physically two independent circuits. This single-stator core integrated dual-winding synchronous motor design has many advantages, such as saving space, structure, and material costs, and avoiding the redundant structure of separate electric and generator motors required by coaxial connection schemes. In addition, the magnetomotive forces generated by the two windings in the same core can be superimposed or canceled out, and the magnetic circuit utilization rate can be optimized by specifically designing the winding arrangement. The rotor 4, as the only rotating body, serves both electric and generator functions, and its rotational inertia can be shared and utilized by both systems, which is the physical basis for achieving inertial response.

[0032] When frequency disturbances occur on the output side of the new energy system or the external power grid side, the mechanical inertia of rotor 4 plays a core regulating role. If the grid frequency drops sharply, rotor 4 maintains its original speed higher than the grid synchronous speed due to inertia. At this time, the frequency of the induced electromotive force of generator winding 2 is higher than the grid frequency, and the kinetic energy of rotor 4 is converted into electrical energy through electromagnetic torque and output to the grid. This manifests as rotor 4 decelerating and releasing kinetic energy to support the grid frequency. Conversely, if the grid frequency rises sharply, the speed of rotor 4 drops below the synchronous speed. Generator winding 2 absorbs electrical energy from the grid and converts it into kinetic energy to accelerate rotor 4. This process absorbs excess electrical energy to suppress the frequency rise. On the new energy side, when a sudden change in input power causes frequency fluctuations, motor winding 1 can also trigger the absorption or release of rotor 4's kinetic energy by adjusting the torque component of the input current. This bidirectional inertia response capability stems from the design of rotor 4 as a shared energy storage element, whose rotational inertia serves both systems simultaneously, while the magnetic field regulation capability of excitation winding 5 further enhances the dynamic response accuracy.

[0033] Regarding the energy transfer process, this embodiment requires explanation. In actual operation, the electrical energy input from the new energy system to the motor winding 1 is necessarily greater than the net electrical energy output from the generator winding 2 to the grid. This is because the synchronous motor also has multiple energy losses: copper losses in the stator dual windings, eddy current and hysteresis losses in the stator core 3, wind resistance and bearing friction losses from the rotor 4 rotation, and the excitation winding 5 itself consumes drive current. Furthermore, leakage flux and harmonic effects during magnetic circuit coupling also lead to additional losses. These losses are all compensated by the electrical energy input from the new energy system; therefore, the system efficiency is characterized by input power always being greater than output power. Nevertheless, this integrated design, by eliminating intermediate losses in traditional two-stage conversion, still achieves an overall efficiency improvement, and its application focuses on improving space utilization and supporting inertia response.

[0034] In this embodiment, the electric winding 1 and the generator winding 2 divide the stator core 3 into an electric core region and a generator core region. An electric air gap exists between the rotor 4 and the electric core region, and a generator air gap exists between the rotor and the generator core region. The electric core region and the generator core region form a magnetic circuit structure on the stator core 3 that can be understood as physically separated. The electric air gap and the generator air gap each independently constitute key components of a closed magnetic circuit, and their dimensions can be equal. This partitioning design allows the magnetic flux generated by the electric winding 1 and the magnetic flux induced by the generator winding 2 to form directional flow paths within the stator core 3. Through the interaction of the air gap and the excitation magnetic field of the rotor 4, it ensures that the electromagnetic energy conversion processes of the two winding systems do not interfere with each other spatially, while simultaneously sharing the rotational kinetic energy of the rotor 4.

[0035] In this embodiment, the rotating shaft 6 is also equipped with a flywheel via a key, spline, or interference fit. This flywheel is integrated into the rotating system as a mechanical inertia enhancement module. The flywheel's mass distribution design gives it a high moment of inertia, storing excess kinetic energy during rotor acceleration and releasing the stored mechanical energy during deceleration, thereby significantly improving the rotor 4's inertial buffering capacity against grid frequency fluctuations. This design essentially expands the dynamic adjustment margin of the rotor 4. When there are sudden power changes on the renewable energy side or grid frequency disturbances, the flywheel can work in conjunction with the excitation control system to achieve a smoother speed transition, effectively suppressing the risk of system oscillation.

[0036] Example 2 Based on Example 1, this example introduces... Figure 1 The synchronous motor shown is a case where a radial flux structure is used; Figure 1 The synchronous motor shaft 6 is omitted from the text.

[0037] In this embodiment, in the radial flux structure, both the motor winding 1 and the generator winding 2 are composed of three phases. Each phase of the motor winding 1 or generator winding 2 is spatially distributed at an electrical angle of 120 degrees. The coils of each phase of the motor winding 1 or generator winding 2 are connected by wires to form a closed loop, which is evenly distributed on the stator core 3. The stator core 3 has a ring structure and surrounds the inner side of the frame 7 of the synchronous motor.

[0038] Based on the above structure, the rotor 4 is located at the center of the stator core 3, and excitation windings 5 ​​are respectively surrounding the two ends of the rotor 4, forming two magnetic poles of the rotor 4.

[0039] In this embodiment, the synchronous motor adopts a radial flux structure, and its flux path extends perpendicular to the axial direction of the rotating shaft 6, that is, along... Figure 1 The stator core 3 extends parallel to the surface of rotor 4 and passes through the air gap into rotor 4 along the radial direction of stator core 3. In this configuration, the annular stator core 3 is coaxially nested inside the frame 7, forming a uniform annular magnetic circuit channel. Both the motor winding 1 and the generator winding 2 are composed of three-phase windings, with each phase winding arranged at a strict 120-degree electrical angle interval on the stator circumference to ensure spatial symmetry. Each phase coil is connected by wires to form an independent closed loop and is uniformly embedded in the slots of stator core 3 with the same slot fill factor, so that the motor side and generator side windings form an electromagnetic structure similar to a mirror image distribution.

[0040] The rotor 4 is coaxially positioned at the neutral position of the stator core 3, with excitation windings 5 ​​tightly wound around its two ends, forming two symmetrically distributed main magnetic poles. When the excitation current passes through the windings, multiple sets of magnetic lines of force are generated, starting from the N pole of the rotor 4, passing radially perpendicularly through the electro-electric air gap and the generator air gap, correspondingly entering the electro-electric core region and the generator core region, and then radially returning to the S pole of the rotor 4, forming a complete radial magnetic flux closed loop. This configuration ensures that the rotating magnetic field generated by the electro-electric winding 1 and the electromotive force induced by the generator winding 2 both strictly follow the radial magnetic field action mechanism, that is, the direction in which the conductor cuts the magnetic lines of force is always perpendicular to the center line of the shaft.

[0041] The advantages of the radial flux structure lie in the high efficiency and dynamic balance of its magnetic circuit. The radial magnetic lines pass through the air gap perpendicularly along the shortest path, significantly reducing magnetic reluctance loss and allowing the excitation magnetic field to be more fully coupled to the stator windings on both sides. The tangential electromagnetic force generated after the motor winding 1 is energized directly drives the rotor 4 to rotate without axial force interference, ensuring the smoothness of torque transmission. The symmetrical layout of the dual magnetic poles makes the radial magnetic pull on the rotor 4 cancel each other out, avoiding bearing wear caused by unilateral magnetic pull. At the same time, the stator windings evenly distributed at 120 degrees effectively suppress spatial harmonics and reduce core vibration and noise.

[0042] The radial flux structure of this embodiment is particularly suitable for medium and high speed applications. Its compact concentric circle layout not only saves axial space, but also enhances the synchronous response capability of rotor 4 to frequency disturbances of the grid on both sides through magnetic pole symmetry. That is, when the power of the new energy side changes suddenly, the radial magnetic field can instantly transmit the torque change to the power generation side, so that the inertia stored in rotor 4 and flywheel (if any) can be efficiently converted into grid support force through the vertical magnetic circuit.

[0043] Example 3 Based on Example 1, this example introduces... Figure 2 The synchronous motor shown is an example of one with an axial flux structure; Figure 2 This is a side sectional view, where the sectioning points are the positions of one cylindrical core in the upper and lower stator cores.

[0044] In this embodiment, the stator core 3 is composed of multiple cylindrical cores evenly arranged along the circumference in the axial flux structure, and each cylindrical core is surrounded by an electric winding 1 and a generator winding 2.

[0045] Based on the above structure, rotor 4 is located on the same side of multiple cylindrical iron cores, and the diameter of rotor 4 matches the diameter of the circumferential structure formed by the arrangement of multiple cylindrical iron cores. An excitation winding 5 is arranged on the surface of rotor 4 near the cylindrical iron cores. The coils of the excitation winding 5 are connected by wires to form a closed loop, and the position of the coils of the excitation winding 5 corresponds to the position of the circumferential structure formed by the arrangement of multiple cylindrical iron cores. Spatially, the motor winding 1 can be located between the excitation winding 5 and the generator winding 2.

[0046] In this embodiment, the magnetic lines of force of the axial flux structure extend parallel to the direction of the rotating shaft 6, penetrating vertically from the end face of the rotor 4 to the stator core 3 along the axial direction. In this configuration, the stator core 3 is composed of multiple cylindrical core units arranged equidistantly along the circumference to form a ring array. The outer cylindrical surface of each unit independently surrounds the electric winding 1 and the generator winding 2, forming a distributed electromagnetic module. The rotor 4 is coaxially disposed on one side of the axial direction of the stator array, and the diameter of its disc-shaped structure matches the diameter of the stator array ring. A ring excitation winding 5 is laid on the end face of the rotor 4 near the stator. This winding forms an excitation magnetic field source concentric with the circumference of the stator through a closed conductor loop.

[0047] Its key spatial layout is as follows: on the magnetic flux path, the electric winding 1 is arranged close to the excitation winding 5, while the generator winding 2 is located on the side of the electric winding 1 away from the excitation winding 5, forming an axial stacked channel similar to "excitation → electric → generator".

[0048] The core of the axial flux working mechanism is as follows: When the excitation current is activated, magnetic lines of force are emitted perpendicularly from the end face of rotor 4, first penetrating to the electric winding 1. This induces a current in the coil conductors of the electric winding 1, generating a tangential electromagnetic force, which in turn drives rotor 4 to rotate. The remaining magnetic flux continues to penetrate axially to the region of the generator winding 2, cutting the conductors of the generator winding 2 to induce a three-phase electromotive force. This design gives the electric winding 2 a dual function: it acts as an actuator for converting electrical energy to mechanical energy on the new energy side, and also as a flux distributor, allowing control of the magnetic flux density transmitted to the generator side by adjusting the current on the electric side.

[0049] The advantage of the axial flux structure is that the distributed stator core 3 allows its upper windings to be directly exposed to the cooling medium. Combined with the short path characteristics of axial flux, it improves the heat dissipation efficiency per unit volume and supports higher current density operation. The stacked winding layout decouples the electromagnetic coupling of electric and power generation functions in the axial space. When the power of the new energy side changes suddenly, the electric winding 1 can instantly adjust the magnetic flux penetration depth to suppress the transmission of disturbances to the power grid on the power generation side. The modular stator unit supports prefabrication. The excitation winding 5 is integrated on the rotor 4 disk using planar printing technology, which greatly reduces the risk of centrifugal stress under high-speed rotation.

[0050] The axial flux structure of this embodiment is particularly suitable for low-speed, high-torque scenarios. Its flattened topology significantly shortens the magnetic circuit length, resulting in a certain degree of improvement in the rotor 4's inertial response speed compared to the radial structure. When the grid frequency fluctuates, the kinetic energy stored in the rotor 4 and flywheel (if any) is directly converted into electromagnetic energy regulation of the dual-sided windings through the axial flux. Furthermore, the axially adjacent design of the excitation winding 5 and the dual windings further reduces the transmission delay of the magnetic field control signal.

[0051] Example 4 Based on any of the above embodiments, this embodiment provides a preferred description of how the synchronous motor suppresses system power oscillations. The synchronous motor is also equipped with a controller for suppressing system power oscillations. The controller includes a power system stabilizer (PSS) and an automatic voltage regulator (AVR). The PSS is configured to receive input signals corresponding to the synchronous motor's operating state, including speed, frequency, and / or output power. The PSS generates additional control signals to enhance system damping based on the input signals and outputs them to the AVR. The AVR adjusts the excitation current applied to the excitation winding 5 according to the additional control signals, enabling the synchronous motor to operate under over-excitation or under-excitation.

[0052] In this embodiment, the oscillation suppression controller configured in the synchronous motor constitutes the control center for dynamic stability, and its core is the closed-loop control achieved by the PSS and AVR working together. The PSS continuously monitors the real-time speed of rotor 4, the frequency fluctuation characteristics of the dual-side power grid, and the transient gradient of output power, and converts mechanical parameters into electrical control commands through a built-in algorithm. When periodic oscillation or gigabit power oscillation of rotor 4 is detected, the PSS generates an additional control signal with specific amplitude-frequency characteristics based on the phase compensation principle. This signal is essentially the electrical equivalent of the damping force injected into the system.

[0053] After receiving the additional control signal, the AVR superimposes it onto the base voltage regulation output to dynamically correct the current setpoint of the excitation winding 5. Under overexcitation, the enhanced magnetic field energy makes the rotor 4 exhibit electrical rigidity, absorbing excess kinetic energy from the grid and suppressing frequency spikes. Under underexcitation, the weakened magnetic field induces the rotor 4 to release kinetic energy, supplementing the system's power deficit to raise the frequency. This bidirectional excitation regulation directly controls the balance between electromagnetic and mechanical power by changing the phase angle of the electromotive force within the synchronous motor, eliminating the energy accumulation process of power oscillations at its source.

[0054] This control mechanism can be effectively coupled with the characteristics of the synchronous motor in this embodiment. The high inertia of rotor 4 and flywheel provides a critical time window for excitation regulation, enabling changes in magnetic field strength to smoothly track the oscillation frequency. The independent magnetic circuit design of the dual windings avoids crosstalk between the motor side and the generator side caused by the control signal. When the input power on the renewable energy side oscillates due to sudden changes in wind speed, the controller prioritizes stabilizing the torque of motor winding 1, and then transmits the smoothed power to the generator side through modulation of the excitation current, achieving coordinated suppression of grid oscillations on both sides.

[0055] Compared to traditional single-stator winding synchronous motors and their single-point control methods, this embodiment simultaneously addresses three key physical dimensions during oscillation suppression: adjusting the magnetic field energy storage intensity through excitation current, utilizing the rotor's four-inertia to buffer sudden power surges, and leveraging the decoupling characteristics of the dual windings to block the oscillation propagation path. This coordinated process enables the synchronous motor to maintain a stable angle of attack within a safe threshold even when encountering grid short-circuit impacts or a sharp drop in renewable energy power, resulting in a significantly improved equivalent damping coefficient compared to conventional units.

[0056] In summary, the synchronous motor of this invention integrates motoring and power generation functions through a single stator and dual winding structure. It utilizes the excitation winding 5 to construct a controllable magnetic field, and leverages the shared inertia of the rotor 4 to provide bidirectional frequency support. The dual-winding neutral point isolation design ensures electrical independence, excitation control enhances system adaptability, and the magnetic circuit coupling mechanism achieves efficient energy transfer. Its compact structure, integrated functions, and rapid dynamic response make it particularly suitable for applications in new energy grid-connected systems with stringent requirements for space efficiency and grid support capabilities.

Claims

1. A synchronous motor integrating electric drive and power generation, comprising a frame (7), a stator core (3), a rotor (4), and a shaft (6), wherein the stator core (3) and the shaft (6) are both mounted on the frame (7), and the rotor (4) is sleeved on the shaft (6); characterized in that: The stator core (3) is provided with stator windings, which include independent electric windings (1) and generator windings (2). The electric windings (1) and generator windings (2) are positioned correspondingly, and their neutral points are not connected. The electric windings (1) are connected to the output side of the new energy system, and the generator windings (2) are connected to the external power grid. The rotor (4) is provided with excitation windings (5), which are used to generate a main magnetic field under the action of externally input excitation current.

2. The integrated synchronous motor according to claim 1, characterized in that: The electric winding (1) and the generator winding (2) divide the stator core (3) into an electric core area and a generator core area; there is an electric air gap between the rotor (4) and the electric core area, and there is a generator air gap between the rotor and the generator core area.

3. The integrated synchronous motor according to claim 1, characterized in that: The shaft (6) is also fitted with a flywheel via a key, spline, or interference fit.

4. The integrated synchronous motor according to claim 1, characterized in that: The synchronous motor can be constructed using either a radial flux structure or an axial flux structure.

5. The integrated synchronous motor according to claim 4, characterized in that: In the radial flux structure, the electric winding (1) and the generator winding (2) are both composed of three phases. Each phase of the electric winding (1) or the generator winding (2) is spatially distributed at an electrical angle of 120 degrees. The coils of each phase of the electric winding (1) or the generator winding (2) are connected by wires to form a closed loop and are evenly distributed on the stator core (3). The stator core (3) has a ring structure and surrounds the inner side of the frame (7) of the synchronous motor.

6. The integrated synchronous motor according to claim 5, characterized in that: The rotor (4) is located at the center of the stator core (3), and the excitation windings (5) are respectively surrounded at both ends of the rotor (4), forming two magnetic poles of the rotor (4).

7. The integrated synchronous motor according to claim 4, characterized in that: In the axial flux structure, the stator core (3) is composed of multiple cylindrical cores evenly arranged along the circumference, and each cylindrical core is surrounded by the electric winding (1) and the generator winding (2).

8. The integrated synchronous motor according to claim 7, characterized in that: The rotor (4) is located on the same side of the plurality of cylindrical iron cores, and the diameter of the rotor (4) is adapted to the diameter of the circumferential structure formed by the arrangement of the plurality of cylindrical iron cores; the excitation winding (5) is provided on the surface of the rotor (4) near the cylindrical iron cores, and the coils of the excitation winding (5) are connected by wires to form a closed loop, and the position of the coils of the excitation winding (5) corresponds to the position of the circumferential structure formed by the arrangement of the plurality of cylindrical iron cores.

9. The integrated synchronous motor according to claim 1, characterized in that: The rotor (4) is used to rotate itself and reach synchronous speed through an external starting device after the main magnetic field is generated by the excitation winding (5); The electric winding (1) is used to be connected to the output side of the new energy system after the rotor (4) reaches the synchronous speed; The rotor (4) is also used to disconnect the external starting device after the electric winding (1) is connected to the output side of the new energy system, and maintain its own rotation at synchronous speed under the voltage action of the output side of the new energy system. The generator winding (2) is used to induce a three-phase AC electromotive force in its own coil when the rotor (4) maintains synchronous speed under the voltage action of the output side of the new energy system, forming AC power and then connecting it to the external power grid side after synchronization, so that the synchronous motor completes the power transfer from the output side of the new energy system to the external power grid side. The rotor (4) is also used to provide inertial response for the power transmission process by absorbing excess electrical energy to accelerate rotation or releasing its own rotational kinetic energy to decelerate when the frequency of the output side of the new energy system or the external power grid changes.

10. The integrated synchronous motor according to claim 1, characterized in that: The synchronous motor is also equipped with a controller for suppressing system power oscillations. The controller includes a power system stabilizer and an automatic voltage regulator. The power system stabilizer is configured to receive input signals corresponding to the synchronous motor in its operating state. The input signals include speed, frequency, and / or output power. The power system stabilizer generates an additional control signal for enhancing system damping based on the input signals and outputs it to the automatic voltage regulator. The automatic voltage regulator adjusts the excitation current applied to the excitation winding (5) based on the additional control signal, so that the synchronous motor can achieve over-excitation or under-excitation operation.

Images