Dual rotor permanent magnet generator

Abstract

A dual rotor permanent magnet generator is provided. The dual rotor permanent magnet generator includes a stator having a plurality of stator slots, an inner rotor having a plurality of rotor poles, an outer rotor including a plurality of permanent magnets, the outer rotor being disposed between the stator and the inner rotor, and a set of windings installed on the stator through the plurality of stator slots such that the set of windings is shared (i.e., simultaneously / parallel) by a magnetic gear motor and a Vernier permanent magnet motor of the dual rotor permanent magnet generator to generate an induced voltage. Also provided is a power generation system including the dual rotor permanent magnet generator, a method of operating the power generation system, and a method of manufacturing the dual rotor permanent magnet generator.

Description

Cross-references to related applications

[0001] This application claims priority to Singapore Patent Application No. 10202400443R, filed on February 19, 2024, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0002] The present invention generally relates to a dual-rotor permanent magnet (PM) generator and a power generation system including the dual-rotor permanent magnet generator. Background Technology

[0003] Power generation systems are crucial in various sectors, including transportation (such as automobiles, ships, and aircraft) and renewable energy (such as wind turbines), where they generate electricity for a variety of technological applications, such as charging batteries, powering onboard devices, and supplying power infrastructure. A key requirement for these power generation systems is variable-speed constant-amplitude (VSCA) voltage operation, which aims to maintain a constant (or nearly constant) voltage at different speeds (such as the external rotor speed under different operating conditions). This is critical because significant voltage fluctuations can damage electrical loads and power converters, as well as reduce power supply efficiency.

[0004] Traditionally, asynchronous generators or induction generators have been used to achieve VSCA voltage operation. However, these generators typically suffer from low torque / power density, low efficiency, and complex control mechanisms. In contrast, permanent magnet (PM) synchronous generators are known for their high torque / power density, high efficiency, and simpler control. However, PM synchronous generators usually require a full-power controllable converter to achieve VSCA voltage operation, resulting in increased cost and efficiency losses due to converter operation.

[0005] The emergence of dual-rotor PM generators offers an attractive solution for VSCA voltage operation using uncontrolled diode rectifiers. This is achieved, for example, by adjusting the position of the inner rotor relative to the outer rotor speed under different operating conditions. However, the conventional design of these dual-rotor PM generators requires two different sets of windings with different pole pairs for two motor sections: a magnetic geared motor (MGM) section and a vernier permanent magnet (VPM) motor section. This conventional design suffers from various technical problems, including complex winding design, increased manufacturing costs, complex control, reduced reliability, and, more importantly, unsatisfactory electromagnetic performance due to inefficient utilization of the slot conductor area and PM field in the motor. For illustrative purposes, Figure 1 A schematic diagram of the topology of this conventional dual-rotor PM generator is shown.

[0006] Therefore, there is a need for a dual-rotor permanent magnet (PM) generator designed to overcome or at least improve upon one or more of the shortcomings of conventional dual-rotor PM generators, and more particularly, to achieve VSCA voltage operation in a highly efficient and effective manner (e.g., efficient / simpler winding design), with good / improved electromagnetic performance and reduced manufacturing costs. It is against this backdrop that the present invention was developed. Summary of the Invention

[0007] According to a first aspect of the present invention, a dual-rotor permanent magnet generator is provided, comprising: A stator with multiple stator slots; An internal rotor with multiple rotor poles; An outer rotor comprising multiple permanent magnets is arranged between the stator and the inner rotor; and A set of windings, which is mounted on the stator through the plurality of stator slots, is shared by the magnetic gear motor and the vernier permanent magnet motor of the dual-rotor permanent magnet generator to generate an induced voltage.

[0008] According to a second aspect of the present invention, a power generation system is provided, comprising: The dual-rotor permanent magnet generator according to the first aspect of the present invention described above; and A speed-dependent device connected to one of the inner rotor and the outer rotor for controlling it.

[0009] According to a third aspect of the present invention, a method for operating a power generation system according to the second aspect of the present invention described above is provided, the method comprising: using a speed-related device of the power generation system to control the angular position of one of the inner rotor and the outer rotor based on the speed of the other of the inner rotor and the outer rotor to perform variable speed constant amplitude (VSCA) voltage operation related to induced voltage.

[0010] According to a fourth aspect of the present invention, a method for manufacturing a dual-rotor permanent magnet generator is provided, comprising: Provide a stator with multiple stator slots; Provides an internal rotor with multiple rotor poles; Provides an outer rotor comprising a plurality of permanent magnets, the outer rotor being arranged between the stator and the inner rotor; and A set of windings is installed on the stator through the multiple stator slots, such that the set of windings is shared by the magnetic gear motor and the vernier permanent magnet motor of the dual rotor permanent magnet generator to generate induced voltage. Attached Figure Description

[0011] The embodiments of the present invention will be better understood and readily recognized by those skilled in the art through the following written description, by way of example only, and in conjunction with the accompanying drawings, wherein: Figure 1 A schematic diagram of the topology of a conventional dual-rotor permanent magnet (PM) generator with two different sets of windings is depicted. Figure 2 A schematic diagram of the topology of a dual-rotor PM generator according to various embodiments of the present invention is depicted. Figure 3 A schematic diagram of a power generation system including a dual-rotor PM generator according to various embodiments of the present invention is depicted; Figure 4A Methods of operating a power generation system according to various embodiments of the present invention are described; Figure 4B A schematic block diagram of a control system for operating a power generation system according to various embodiments of the present invention is depicted. Figure 5 Methods for manufacturing a dual-rotor PM generator according to various embodiments of the present invention are described; Figure 6 The illustration depicts schematic diagrams of power generation systems operating at VSCA voltage in various industrial applications, showing the case of a conventional dual-rotor PM generator and the case of this dual-rotor PM generator according to various exemplary embodiments of the present invention; Figure 7A A schematic diagram illustrating a conventional system configuration operating at VSCA voltage is depicted for stand-alone wind power generation using a portion of the power converter of a DFIG (doubly fed induction generator). Figure 7B A schematic diagram illustrating a conventional system configuration operating at VSCA voltage is depicted for stand-alone wind power generation using a full-power converter of an IG / SG (induction generator or synchronous generator). Figure 7C A schematic diagram illustrating a conventional system configuration operating at VSCA voltage is depicted for stand-alone wind power generation using a diode rectifier of a DRPMG (dual rotor permanent magnet generator). Figure 8A and Figure 8B The diagram illustrates the winding and rotor design / configuration of a reference / conventional DRPMG and a DRPMG of this disclosure according to various exemplary embodiments of the present invention; Figure 9 A schematic diagram illustrating the configuration of a stand-alone wind power generation system operating with VSCA voltage is depicted, showing the case of a baseline / conventional DRPMG and the case of a DRPMG according to various exemplary embodiments of the present disclosure; Figure 10Depicting Figure 9 A vector diagram of the induced voltage on the external rotor used for VSCA voltage operation at different speeds; Figure 11 Table I shows example key design parameters for the three generators under study: PMSG (Permanent Magnet Synchronous Generator), the baseline DRPMG, and the DRPMG of this disclosure according to various example embodiments of the invention. Figure 12 The no-load field distribution of the three generators mentioned above under no-load conditions is shown, including magnetic flux density and magnetic field lines; Figure 13A and Figure 13B The corresponding magnetic flux density in the external air gap is shown, including the waveform and harmonic spectrum; Figure 14A and Figure 14B The no-load induced voltage of the three generators under no-load conditions with a rated external rotor speed of 200 r / min is shown, including the waveform and harmonic spectrum. Figure 15A and Figure 15B The graphs of the no-load induced voltage of the DRPMG of this disclosure at different inner rotor positions and outer rotor speeds are shown, including the relationship between the induced voltage amplitude and the inner rotor position at the rated outer rotor speed of 200 r / min. Figure 15A ) and the waveforms of the induced voltage at different external rotor speeds ( Figure 15B ); Figure 15C A graph showing the dynamic VSCA operation measured by the DRPMG 200 of this disclosure under load conditions is presented, including the outer rotor speed, inner rotor position, A-phase AC induced voltage, rectified DC voltage, and DC output current. Figure 16 The above three generators are shown at 5 A / mm 2 Torque waveform at rated current density; Figure 17 Table II shows various other performance characteristics of the three generators mentioned above, such as power, loss, efficiency, power factor, permanent magnet utilization, etc. Figures 18A to 18E Images of the DRPMG prototype disclosed herein are shown, including its stator, outer rotor, inner rotor, permanent magnets and coils, as well as test fixtures for VSCA operation; Figure 19A and Figure 19B The no-load induced voltage measured at the rated speed of 200 r / min was compared with the induced voltage predicted by FEA; Figure 20A and Figure 20BA graph showing the external rotor torque is presented, including the relationship between torque and current angle at 20A. Figure 20A And the relationship between torque and current amplitude at zero current angle ( Figure 20B );as well as Figure 21A and Figure 21B The measured voltage envelope and the simulated (FEA prediction) voltage envelope of the no-load AC induced voltage at the rated external rotor speed of 200 r / min are shown. Detailed Implementation

[0012] Various embodiments of the present invention provide a dual-rotor permanent magnet (PM) generator and a power generation system including the dual-rotor PM generator.

[0013] As discussed in the background section, a key requirement in various power generation systems is variable speed constant amplitude (VSCA) voltage operation, which aims to maintain an approximately constant voltage at different speeds (e.g., the speed of the outer rotor under different operating conditions). In this regard, the emergence of dual-rotor PM generators offers an attractive solution, enabling VSCA voltage operation using uncontrolled diode rectifiers. However, the conventional design of these dual-rotor PM generators requires two different sets of windings with different pole pairs for two motor sections: a magnetic geared motor (MGM) section and a vernier permanent magnet (VPM) motor section. This conventional design presents various technical problems, including complex winding design, increased manufacturing costs, complex control, reduced reliability, and, more importantly, unsatisfactory electromagnetic performance due to inefficient utilization of the stator slot conductor area and PM field in the motor. A schematic diagram of the topology of such a conventional dual-rotor PM generator is shown below. Figure 1 As shown. In this regard, various embodiments of the present invention provide a dual-rotor PM generator designed to overcome or at least improve upon one or more of the drawbacks of conventional dual-rotor permanent magnet generators, and more particularly, to achieve VSCA voltage operation in an efficient and effective manner, such as through efficient / simpler winding design, good / improved electromagnetic performance, and reduced manufacturing costs.

[0014] Figure 2 A topological schematic diagram of a dual-rotor PM generator 200 according to various embodiments of the present invention is depicted. The dual-rotor PM generator 200 includes: a stator 210 having a plurality of stator slots 214; an inner rotor 220 having a plurality of rotor poles 224; an outer rotor 230 including a plurality of permanent magnets 234, the outer rotor 230 being arranged between the stator 210 and the inner rotor 220; and a set of windings 240 mounted on the stator 210 through the plurality of stator slots 210, such that the set of windings 240 is shared by the magnetic gear motor (MGM) and vernier permanent magnet motor (VPM) of the dual-rotor permanent magnet generator 200 to generate an induced voltage.

[0015] The dual-rotor PM generator 200 advantageously achieves VSCA voltage operation in a highly efficient and effective manner. In particular, a single winding 240 (i.e., a single winding or a single unified winding) is mounted on the stator 210 via multiple stator slots 214, such that this single winding 240 is shared simultaneously / in parallel by the MGM and VPM of the dual-rotor PM generator 200 during operation to generate an induced voltage. Therefore, the dual-rotor PM generator 200 is advantageously configured to achieve VSCA voltage operation in the stator 210 using only a single winding. In this respect, the single winding 240 serves as both the MGM and VPM windings, allowing the MGM and VPM to share (or efficiently utilize) the entire stator slot conductor area, which significantly improves the utilization of the PM magnetic field and increases the power output of the dual-rotor PM generator 200. In contrast, as described in the background art and... Figure 1 As shown, a conventional dual-rotor PM generator requires two different sets of windings with different pole pair numbers for the MGM and VPM. Therefore, as Figure 1 As can be seen, the stator slot conductor area must be divided into two parts, one for the MGM and the other for the VPM windings, with additional insulation (not shown) required between the MGM and VPM windings. This conventional double-set winding in the stator not only complicates the winding design but also leads to suboptimal utilization of the stator slot conductor area, as the corresponding winding set is limited to a portion / segment of the total available stator slot conductor area. Therefore, the dual-rotor PM generator 200 can advantageously achieve VSCA voltage operation in a highly efficient and effective manner, including a more efficient / simpler winding design, better / improved electromagnetic performance, and reduced manufacturing costs. These advantages or technical effects and / or other advantages or technical effects will become more apparent to those skilled in the art as the dual-rotor permanent magnet generator 200 and the corresponding power generation system are described in more detail according to various embodiments and exemplary embodiments of the present invention.

[0016] In various embodiments, the number of stator slots 214 on the stator 210 is equal to the number of rotor poles 224 on the inner rotor 220. In this respect, various embodiments advantageously find that by matching the number of stator slots 214 to the number of inner rotor poles 224, a conventional double-set winding can be unified into a single-set winding 240. In particular, various embodiments find that by matching the number of stator slots 214 to the number of inner rotor poles 224, the number of pole pairs of the MGM and VPM windings is equal, thus allowing the conventional MGM and VPM winding sets to be advantageously unified into a single-set winding 240 in a dual-rotor PM generator 200 according to various embodiments of the invention. Therefore, as Figure 2 As shown, in the dual-rotor PM generator 200, the number of stator slots 214 on the stator 210 is equal to the number of rotor poles 224 on the inner rotor 220. In contrast, as... Figure 1As shown, in a conventional twin-rotor PM generator, the number of stator slots on the stator differs from the number of rotor poles on the inner rotor. Therefore, in a conventional twin-rotor PM generator, the MGM and VPM windings have different pole pair numbers, and thus the MGM and VPM windings cannot be unified into a single winding in a conventional twin-rotor PM generator. In other words, based on conventional teachings / understanding, the MGM and VPM windings cannot be unified into a single winding in a conventional twin-rotor PM generator because this would render the conventional twin-rotor PM generator inoperable or result in unsatisfactory performance. Furthermore, those skilled in the art will understand that in a conventional twin-rotor PM generator, the two windings have different pole pair numbers, resulting in completely different winding distributions within the generator's stator slots. Therefore, a conventional twin-rotor PM generator has and requires two different windings with different pole pair numbers for the MGM and VPM, which does not constitute a single winding (not a single unified winding). In contrast, the dual-rotor PM generator 200 according to various embodiments of the present invention has a set of windings 240 (a single uniform winding) mounted on the stator 210, which is shared simultaneously / in parallel by the MGM and VPM to generate an induced voltage. Therefore, in the uniform winding 240 of the dual-rotor PM generator 200, for example, only a consistent winding distribution in the stator slots 214 is required to achieve a number of pole pairs corresponding to the difference between the number of stator slots 214 and the number of permanent magnet pole pairs in the outer rotor 230.

[0017] Those skilled in the art should understand that Figure 2 The topology of the dual-rotor PM generator 200 shown is an exemplary illustration. The number of stator slots 214 on the stator 210, the number of rotor poles 224 on the inner rotor 220, and the number of permanent magnets 234 embedded in the outer rotor 230 are not limited to the following. Figure 2 The quantities shown. For example, various numbers of stator slots 214 on stator 210 and various numbers of rotor poles 224 on inner rotor 220 can be provided or configured, as long as the number of stator slots 214 on stator 210 is equal to the number of rotor poles 224 on inner rotor 220. For example, the number of stator slots 214 and the number of rotor poles 224 can be any value that is a multiple of the number of phases (e.g., 12, 15, or 18 for a three-phase motor), as long as they are equal.

[0018] In various embodiments, the stator 210, outer rotor 230, inner rotor 220, and a set of windings 240 together constitute an MGM. In various embodiments, the stator 210, outer rotor 230, and set of windings 240 together constitute a VPM. In the MGM, the PM field from the outer rotor 230 is modulated by the rotor poles 224 on the inner rotor 220, generating magnetic harmonics absorbed by the set of windings 240 to induce a voltage. Similarly, in the VPM, the PM field from the outer rotor 230 is modulated by the stator 210, generating harmonics absorbed by the same set of windings 240 to induce a voltage.

[0019] In various embodiments, such as Figure 2 As shown, the stator 210, inner rotor 220, and outer rotor 230 are arranged coaxially around a common axis. In this respect, in various embodiments, a plurality of stator slots 214 are equidistantly (or regularly) circumferentially spaced around the stator 210, a plurality of rotor poles 224 are equidistantly circumferentially spaced around the inner rotor 220, and a plurality of permanent magnets 234 are equidistantly circumferentially spaced around the outer rotor 230.

[0020] In various embodiments, a set of windings 240 is connected to an AC / DC rectifier (e.g., a diode rectifier) ​​to rectify the induced voltage of the set of windings 240 generated during operation to charge the energy storage device.

[0021] In various embodiments, one of the inner and outer rotors 220 and 230 is connected to and controlled by a speed-dependent device (e.g., a servo motor), and the other of the inner and outer rotors 220 and 230 is connected to and controlled by a rotatable device configured to be rotated by an external kinetic energy source (e.g., wind or water power). In various embodiments, to obtain higher power output, the inner rotor 220 is connected to and controlled by the speed-dependent device, and the outer rotor 230 is connected to and controlled by the rotatable device. For example, the outer rotor 230 may be mechanically connected to a shaft, which is then coupled to another shaft mounted in the rotatable device using a coupling. This arrangement facilitates the efficient transfer of rotational energy to the outer rotor 230.

[0022] Figure 3 A schematic diagram of a power generation system 300 according to various embodiments of the present invention is depicted. The power generation system 300 includes: a dual-rotor PM generator 200 as described herein according to various embodiments of the present invention; and a speed-dependent device 320 (e.g., a servo motor) connected to one of the inner and outer rotors 220, 230 (e.g., the inner rotor 220) for controlling it.

[0023] In various embodiments, as described above, another of the inner and outer rotors 220, 230 (e.g., outer rotor 230) is coupled to and controlled by a rotatable device 330 configured to be rotated by an external kinetic energy source (e.g., wind or hydropower). For example, the power generation system 300 may be a wind power generation system or a hydropower generation system (e.g., for off-grid applications).

[0024] In various embodiments, the power generation system 300 also includes a control system 420 (described below) communicatively coupled to the speed-dependent device 320 for operating the power generation system 300. Specifically, the control system 420 is configured to control the speed-dependent device 320 to control the angular position of one of the inner and outer rotors 220, 230 (e.g., the inner rotor 220) based on the speed of the other of the inner and outer rotors 220, 230 (e.g., the outer rotor 230) to perform VSCA voltage operation associated with the induced voltage (i.e., the total induced voltage or net induced voltage). As described herein, VSCA voltage operation aims to maintain a constant (or approximately constant) voltage at different speeds (e.g., different outer rotor speeds under different operating conditions (e.g., speed variations of wind turbine blades at different wind speeds and pressures)).

[0025] In various embodiments, the power generation system 300 further includes: an AC / DC rectifier connected to the set of windings 240; and an energy storage device connected to the AC / DC rectifier. In this regard, the AC / DC rectifier is configured to rectify the induced voltage of the set of windings 240 generated during operation for charging the energy storage device. In various embodiments, the AC / DC rectifier is a diode rectifier.

[0026] Figure 4AA method 400 for operating a power generation system 300 according to various embodiments of the present invention is described. Method 400 includes using a speed-dependent device 320 of the power generation system 300 to control (at 406) the angular position of one of the inner and outer rotors 220, 230 (e.g., the inner rotor 220) based on the speed of the other one (e.g., the outer rotor 230) to perform VSCA voltage operation associated with the induced voltage. According to various embodiments, the magnitude of the total induced voltage or net induced voltage in a set of windings 240 is determined by the vector sum of the induced voltages of the MGM and VPM. In this respect, for example, when the speed-dependent device 320 is connected to the inner rotor 220, the vector angle between the two induced voltages can be controlled by adjusting the angular position of the inner rotor 220, thereby enabling precise adjustment of the total induced voltage to achieve VSCA operation. According to various embodiments, the speed of the outer rotor 230 does not need to be directly measured, as its effect is reflected in the rectified output voltage of the AC / DC rectifier. In this regard, for example, when the outer rotor 230 is coupled to and controlled by a rotatable device, a voltage sensor is used to dynamically monitor the rectified output voltage as the speed of the outer rotor 230 changes in response to variations in the rotatable device. For example, the angular position of the inner rotor 220 can be detected by a position sensor (e.g., an encoder or resolver), which provides feedback to the control system for operating the power generation system 300 (e.g., a standard PI (proportional-integral) controller can be embedded in the control system). The control system can take the difference between the measured rectified output voltage (e.g., based on the speed of the outer rotor 230) and the desired constant output voltage as input. Based on this voltage difference and feedback regarding the inner rotor position, the control system can generate a control signal and send it to a speed-dependent device 320 (e.g., a servo motor) to control the speed-dependent device 320 to adjust the angular position of the inner rotor 220. Therefore, such an exemplary closed-loop control system enables consistent VSCA voltage operation even when the outer rotor speed varies.

[0027] Figure 4B A schematic block diagram of a control system 420 for operating a power generation system 300 according to various embodiments of the present invention is depicted, corresponding to the above-described references to various embodiments of the present invention. Figure 4AThe method 400 for operating the power generation system 300 is described above. The control system 420 includes: at least one memory 422; and at least one processor 424 communicatively connected to the at least one memory 422 and configured to execute the method 400 for operating the power generation system 300 described above according to various embodiments of the present invention. Therefore, the at least one processor 424 is configured to use the speed-related device 320 of the power generation system 300 (by generating and sending control signals thereto) to control the angular position of one of the inner and outer rotors 220 and 230 (the aforementioned one) based on the speed of the other of the inner and outer rotors 220 and 230 to perform VSCA voltage operation related to the induced voltage.

[0028] Those skilled in the art will understand that at least one processor 424 can be configured to perform various functions or operations via an instruction set (e.g., software modules) executable by at least one processor 424. Therefore, as Figure 2 As shown, the control system 420 may include an angular position control module (or angular position control circuit) 426, which is configured to use the speed-related device 320 of the power generation system 300 to control the angular position of one of the inner and outer rotors 220 and 230 (the one mentioned above) based on the speed of the other of the inner and outer rotors 220 and 230 to perform VSCA voltage operation related to the induced voltage.

[0029] In various embodiments, the control system 420 for operating the power generation system 300 corresponds to the above reference. Figure 4A The method 400 for operating the power generation system 300, therefore, various operations, functions, or steps configured to be executed by at least one processor 424 can correspond to various operations, functions, or steps of the method 400 described above according to various embodiments, and therefore, for clarity and brevity, there is no need to repeat the description of the control system 420. In other words, the various embodiments described herein in the context of methods (e.g., the method 400 for operating the power generation system 300) are similarly applicable to corresponding systems or apparatuses (e.g., the control system 420 for operating the power generation system 300), and vice versa. For example, in various embodiments, at least one memory 422 may store an angular position control module 426 corresponding to the corresponding operations, functions, or steps of the method 400 for operating the power generation system 300 described above according to various embodiments, which can be executed by at least one processor 204 to perform the corresponding operations, functions, or steps described herein.

[0030] According to various embodiments of the present invention, a computing system, controller, microcontroller, or any other system providing processing capabilities can be provided. Such a system can be considered to include more than one processor and more than one computer-readable storage medium. For example, the control system 420 described above may include at least one processor (or controller) 424 and at least one computer-readable storage medium (or memory) 422, which are used, for example, in the various processes described herein. The memory or computer-readable storage medium used in the various embodiments may be volatile memory, such as DRAM (Dynamic Random Access Memory), or non-volatile memory, such as PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or flash memory, such as floating gate memory, charge-trapped memory, MRAM (Magnetoresistive Random Access Memory), or PCRAM (Phase Change Random Access Memory).

[0031] In various embodiments, "circuit" can be understood as any type of logical implementation entity, which can be a dedicated circuit or a processor executing software stored in memory, firmware, or any combination thereof. Thus, in embodiments, "circuit" can be hardwired logic circuitry or programmable logic circuitry, such as a programmable processor, such as a microprocessor (e.g., a Complex Instruction Set Computer (CISC) processor or a Reduced Instruction Set Computer (RISC) processor). "Circuit" can also be a processor executing software, such as any type of computer program, such as a computer program using virtual machine code, such as Java. According to various other embodiments, any other type of implementation of various functions or operations can also be understood as "circuit". Similarly, "module" can be part of a system according to various embodiments of the invention and can encompass the "circuit" described above, or can be understood as any type of logical implementation entity therein.

[0032] Some portions of this disclosure are presented, explicitly or implicitly, in the form of algorithms and functional or symbolic representations on data in computer memory. These algorithmic descriptions and functional or symbolic representations are means by which those skilled in the art of data processing most effectively communicate the substance of their work to others skilled in the art. Algorithms herein and generally are conceived as self-consistent sequences of steps that produce desired results. These steps are steps that require physical manipulation of physical quantities, such as electrical, magnetic, or optical signals that can be stored, transmitted, combined, compared, and otherwise manipulated.

[0033] This specification also discloses a system (which may also be embodied as more than one apparatus or device), such as control system 420, for performing various operations, functions, or steps of the various methods described herein. Such a system may be specifically constructed for a desired purpose or may comprise a general-purpose computer system that can be selectively activated or reconfigured by a computer program stored in a computer system. Generally, the various algorithms that may be presented herein are not limited to being implemented or performed by any particular computer system. Alternatively, more specialized computer systems may be provided as needed or suitably to perform the various operations, functions, or steps of the various methods described herein without departing from the scope of the invention.

[0034] Furthermore, this specification implicitly discloses computer programs or software / functional modules, as it will be readily apparent to those skilled in the art that various operations, functions, or steps of the various methods described herein can be implemented using computer code. The computer program is not intended to be limited to any particular programming language or its implementation, and those skilled in the art will understand that various programming languages ​​and their encodings can be used to implement the computer program. Furthermore, the computer program is not intended to be limited to any particular control flow, as various programming languages ​​exist that can use different control flows. Those skilled in the art will understand that the computer program can be stored on any computer-readable storage medium (non-transitory computer-readable storage medium), such as, but not limited to, a disk, optical disk, or memory chip. For example, a computer program stored on a computer-readable storage medium can be loaded and executed on a computer system to implement various operations, functions, or steps of the various methods described herein according to various embodiments of the present invention.

[0035] Therefore, in various embodiments, a computer program product is provided, implemented in one or more computer-readable storage media (non-transitory computer-readable storage media), including instructions (e.g., angular position control module 426) executable by one or more computer processors to perform the above-described instructions. Figure 4A The method 400 for operating the power generation system 300 according to various embodiments of the present invention. Therefore, the various computer programs or software modules described herein can be stored in a computer program product that can be received by the system, such as... Figure 4B The control system 420 shown is executed by at least one processor 204 of the control system 200 to perform various operations, functions, or steps of the various methods described herein according to various embodiments of the present invention.

[0036] Those skilled in the art will understand that the various modules described herein (e.g., angular position control module 426) can be software modules implemented by computer programs or instruction sets executable by a computer processor to perform various functions or operations. The various modules described herein (e.g., angular position control module 426) can also be implemented as hardware modules, which are functional hardware units designed to perform various functions or operations. More specifically, in a hardware sense, a module is a functional hardware unit designed to be used in conjunction with other components or modules. For example, a module can be implemented using discrete electronic components, or it can form part of an entire electronic circuit, such as an application-specific integrated circuit (ASIC). Many other possibilities exist. Those skilled in the art will also understand that combinations of hardware and software modules can be implemented. Furthermore, the various operations, functions, or steps of the various methods described herein can be performed in parallel rather than sequentially as needed or appropriately (e.g., as long as it does not render the method inoperable or unsatisfactory to its intended purpose).

[0037] Figure 5 A method 500 for manufacturing a dual-rotor PM generator 200 according to various embodiments of the present invention is described. Method 500 includes: (at 502) providing a stator 210 having a plurality of stator slots 214; (at 504) providing an inner rotor 220 having a plurality of rotor poles 224; (at 506) providing an outer rotor 230 including a plurality of permanent magnets 234, the outer rotor 230 being arranged between the stator 210 and the inner rotor 220; and (at 508) mounting a set of windings 240 on the stator 210 through the plurality of stator slots 214, such that the set of windings 240 is shared by the MGM and VPM of the dual-rotor PM generator 200 to generate an induced voltage. In various embodiments, a single set of windings 240 is configured with a number of pole pairs equal to the difference between the number of stator slots 214 in the stator 210 and the number of PM pole pairs in the outer rotor 230. In various embodiments, the design parameters of the stator 210, inner rotor 220, outer rotor 230, and a set of windings 240 can be appropriately optimized (e.g., using a genetic algorithm). As illustrative examples and without imposing limitations, various example design parameters of the dual-rotor PM generator 200 according to various exemplary embodiments of the invention will be referred to below. Figure 11 The description is presented in Table I.

[0038] In various embodiments, method 500 is used to manufacture as described herein. Figure 2The dual-rotor PM generator 200 described herein according to various embodiments is such that the various steps or operations of method 500 may correspond to forming, providing, or configuring various components, parts, or portions of the dual-rotor PM generator 200 as described herein according to various embodiments. Therefore, for clarity or brevity, it is unnecessary to describe or repeat these corresponding steps or operations with respect to method 500. In other words, the various embodiments described herein in the context of dual-rotor PM generator 200 are similarly applicable to method 500 (e.g., for manufacturing a dual-rotor PM generator 200 having the various components, parts, portions, and / or configurations as described above according to various embodiments), and vice versa. Those skilled in the art will also understand that method 500 for manufacturing dual-rotor PM generator 200 is not limited to any particular order of operations / steps. For example, as described above, the number of stator slots 214 on stator 210 is equal to the number of rotor poles 224 on inner rotor 220. Therefore, in method 500, the number of stator slots 214 on stator 210 is equal to the number of rotor poles 224 on inner rotor 220. For example, as described above, the stator 210, inner rotor 220, and outer rotor 230 are arranged coaxially around a common axis. Therefore, in method 500, the inner rotor 220 and outer rotor 230 are arranged coaxially around a common axis.

[0039] Those skilled in the art will understand that the terminology used herein is for describing various embodiments only and is not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, as used in this specification, the terms "comprising" and / or "including" specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of more than one other feature, integer, step, operation, element, component, and / or combination thereof.

[0040] Any reference to an element or feature using names such as "first," "second," etc., in this document does not limit the number or order of such elements or features unless otherwise stated or required by the context. For example, these names may be used herein as a convenient way to distinguish two or more elements or instances of elements. Therefore, a reference to a first element and a second element does not necessarily mean that only two elements can be used, or that the first element must precede the second element, unless otherwise stated or required by the context. Furthermore, the phrase "at least one" in the list of items refers to any single item or any combination of any two or more items.

[0041] To enable the present invention to be readily understood and practiced, various exemplary embodiments of the invention will be described below by way of example only and not limitation. However, those skilled in the art will understand that the invention can be embodied in various different forms or configurations and should not be construed as limited to the exemplary embodiments set forth below. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, fully conveying the scope of the invention to those skilled in the art.

[0042] In particular, to better understand the invention without limiting or losing its generality, various exemplary embodiments of the invention will now be described with respect to a power generation system, wherein, for clarity and brevity, the inner rotor is connected to and controlled by a speed-dependent device (based on control signals from a control system), and the outer rotor is connected to and controlled by a rotatable device. Those skilled in the art will understand that the power generation system is not limited to this particular configuration; as described above, one of the inner and outer rotors may be connected to and controlled by a speed-dependent device, and the other of the inner and outer rotors may be connected to and controlled by a rotatable device configured to be rotated by an external kinetic energy source.

[0043] Various example embodiments provide a unified winding design for a dual-rotor PM generator in a power generation system. In particular, these example embodiments introduce a single unified winding that can be used simultaneously as both the MGM winding and the VPM winding. As described above, Figure 1 and Figure 2Schematic diagrams of the topologies of a conventional dual-rotor PM generator and a dual-rotor PM generator 200 (hereinafter referred to as this dual-rotor PM generator) according to various embodiments of the present invention are shown. It can be seen that in a conventional dual-rotor PM generator, the conductor area in the stator slots is divided into two parts, used for the MGM and VPM windings respectively. In stark contrast, in this dual-rotor PM generator 200, only a single winding 240 is installed in the stator 210, which is shared by both the MGM and VPM to generate an induced voltage (total induced voltage or net induced voltage) during operation. The dual-rotor PM generator 200 includes: a stator 210 with multiple stator slots 214; an inner rotor 220 with multiple rotor poles 224; an outer rotor 230 including multiple permanent magnets 234, the outer rotor 230 being arranged between the stator 210 and the inner rotor 220; and a single winding 240 mounted on the stator 210 through the multiple stator slots 210, such that this single winding 240 is shared (simultaneously / parallel) by the MGM and VPM of the dual-rotor PM generator 200 to generate an induced voltage. Therefore, this single winding 240 serves as both the MGM winding and the VPM winding, allowing the MGM and VPM to share (or efficiently utilize) the entire stator slot conductor area, thereby generating higher torque / power from this dual-rotor PM generator 200. Furthermore, this unified winding design (single winding 240) significantly simplifies winding design, thereby significantly reducing manufacturing costs and improving reliability.

[0044] Figure 6 Schematic diagrams illustrating the configurations of power generation systems operating at VSCA voltage in various industrial applications are provided. For illustrative purposes, the cases of conventional dual-rotor PM generators and the present dual-rotor PM generator 200 according to various exemplary embodiments are shown. In particular, according to various exemplary embodiments, a power generation system is provided including a dual-rotor PM generator 200 and a speed-related device 320 (e.g., a servo motor) connected to an inner rotor 220 for controlling the speed of the inner rotor 220. Various exemplary embodiments have found that the unified winding design in the present dual-rotor PM generator 200 significantly improves generator performance, including induced voltage, torque / power density, efficiency, and permanent magnet utilization, compared to a conventional dual-winding design. Therefore, the present dual-rotor PM generator 200, and more particularly this unified winding design, has great potential for wide application in various power generation systems requiring VSCA voltage operation, such as electric vehicles, all-electric aircraft, electric boats, and wind turbines.

[0045] Therefore, various exemplary embodiments introduce a dual-rotor PM generator 200 equipped with a single unified winding 240 in the stator 210, a winding design not seen in the prior art of dual-rotor PM generators. The developed single unified winding 240 is capable of generating induced voltage and power from the MGM and VPM sections within the dual-rotor PM generator 200. Thus, the single unified winding 240 advantageously simplifies the winding design, reduces control complexity, and significantly enhances the utilization of the stator slot conductor area and PM field within the dual-rotor PM generator 200. According to various exemplary embodiments, by controlling the inner rotor position (i.e., the angular position of the inner rotor 220, which can be defined by the mechanical angle between the centerline of the rotor poles in the inner rotor 220 and the centerline of the slot in the stator 210), the contribution of the MGM section to voltage and power can be flexibly adjusted in the developed unified winding 240, and high-performance and cost-effective VSCA operation is ensured using an uncontrolled diode rectifier 610. According to various example embodiments, the magnitude of the total induced voltage or net induced voltage in the winding 240 is determined by the vector sum of the induced voltages of MGM and VPM. In this respect, by adjusting the angular position of the inner rotor 220, the vector angle between these two induced voltages can be adjusted / controlled to achieve a constant (or approximately constant) voltage at different outer rotor speeds, thereby enabling precise adjustment of the total induced voltage for VSCA operation.

[0046] Therefore, the unified winding design (single unified winding 240) developed according to various example embodiments advantageously controls and generates voltage and power from the two motor sections (i.e., MGM and VPM) within the dual-rotor PM generator 200, resulting in significant improvements in electromagnetic performance compared to conventional dual-rotor PM generators. Thus, the single winding 240 enables control of power contributions from both rotors (inner rotor 220 and outer rotor 230). Furthermore, the developed unified winding design, using an uncontrolled diode rectifier 610, advantageously enables the dual-rotor PM generator 200 to provide high-performance and low-cost VSCA operation. In particular, the developed unified winding design, by controlling the power contribution from one motor section (i.e., MGM), enables low-cost VSCA operation in a dual-rotor PM generator with a single unified winding 240, without the need for two windings as in conventional dual-rotor PM generators. In particular, conventional dual-rotor PM generators require two windings to manage power from both rotors (inner rotor and outer rotor) and both motor sections (i.e., MGM and VPM). Those skilled in the art will understand that in a conventional dual-rotor PM generator, the two sets of windings have different numbers of pole pairs, resulting in completely different winding distributions in the stator slots within the generator. Therefore, a conventional dual-rotor PM generator has and requires two different sets of windings with different numbers of pole pairs for the MGM and VPM, which does not constitute a single winding (not a single unified winding). In contrast, the dual-rotor PM generator 200 has a single winding 240 (a single unified winding) mounted on the stator 210, which is shared simultaneously / in parallel by the MGM and VPM to generate induced voltage. Therefore, in the single unified winding 240 of the dual-rotor PM generator 200, for example, only a consistent winding distribution needs to be provided in the stator slots 214 to achieve a number of pole pairs corresponding to the difference between the number of stator slots 214 and the number of permanent magnet pole pairs of the outer rotor 230. This advancement, associated with the proposed unified winding design, significantly reduces the complexity of winding design and manufacturing costs, simplifies control mechanisms, and improves the utilization of stator slot conductors, thereby enhancing power density, efficiency, and material utilization.

[0047] For better understanding and as an illustrative example, a stand-alone wind power generation system including a dual-rotor PM generator 200 will now be described according to various exemplary embodiments of the present invention. Those skilled in the art will understand that the dual-rotor PM generator 200 is not limited to implementation in wind power generation systems; as described above, the dual-rotor PM generator 200 can be implemented in any power generation system as needed or suitably, particularly when VSCA operation is required.

[0048] For example, stand-alone wind power systems are crucial for supplying electricity to remote areas such as rural communities and offshore islands. Maintaining VSCA voltage across a wide range of wind speeds is essential in these systems. In this regard, various example embodiments provide a dual-rotor permanent magnet generator (DRPMG) 200 characterized by a single set of windings 240 in the stator 210, specifically designed to achieve VSCA voltage usable in stand-alone wind power applications. A comprehensive finite element analysis (FEA) was performed to analyze the DRPMG 200 of this disclosure according to various example embodiments of the present invention (e.g., Figure 2 (as shown) and conventional DRPMGs containing dual windings (e.g.) Figure 1 As shown, this can also be referred to as a benchmark design or benchmark DRPMG. The operating principle of the DRPMG 200 of this disclosure will also be described in detail according to various exemplary embodiments of the invention, and analytical models for single-winding and double-winding configurations will be provided to highlight the performance advantages of the single-winding design according to various exemplary embodiments of the invention. Results show that the DRPMG 200 of this disclosure outperforms conventional PM synchronous generators (PMSGs) and benchmark DRPMGs in terms of induced voltage, torque / power density, efficiency, and PM material utilization. Furthermore, a prototype of the DRPMG 200 of this disclosure was built and tested, and experimental data validated the analysis.

[0049] With increasing concerns about the depletion and pollution of traditional centralized fossil fuels such as coal, oil, and natural gas, significant efforts have been devoted to developing distributed renewable energy sources, such as wind, solar photovoltaic, hydropower, and biomass energy. Due to their decentralized nature, independent generation systems can efficiently utilize these distributed renewable energy sources for electricity supply, particularly in remote areas (such as rural communities and offshore islands) where establishing a grid is not feasible or costly but requires local power supply. Among independent generation systems, wind power is one of the most advantageous options due to its ease of access, the vast untapped potential of wind energy, and the flexibility in the location of power generation installations.

[0050] In stand-alone wind power systems, batteries typically serve as energy storage reservoirs and require a near-constant voltage for efficient and safe charging. Therefore, considering the speed variations of wind turbine blades under different wind speeds and pressures, providing a near-constant voltage (i.e., VSCA voltage operation) is crucial for such wind power systems.

[0051] In recent decades, stand-alone wind power systems have made significant progress, with various wind turbines emerging to convert captured kinetic energy into electricity. Depending on the type of generator and the capacity of the power converter, traditional systems can generally be categorized as follows: Figure 7A The system shown has a partial power converter based on a doubly fed induction generator (DFIG), and as shown in Figure 7BThe system shown has a full-power converter based on an induction generator (IG) or a synchronous generator (SG). In particular, Figure 7A A schematic diagram illustrates a conventional system configuration utilizing a DFIG partial power converter for stand-alone wind power generation, operating at VSCA voltage. Figure 7B A schematic diagram illustrates a conventional system configuration utilizing a full-power converter (DFIG / SG) for stand-alone wind power generation, operating at VSCA voltage. The former system offers the advantage of a small power converter capacity, thus reducing the cost of power electronics and power losses. However, the brushes and slip rings in the DFIG, along with the gearbox in the system, result in the need for regular maintenance, low reliability, and low system efficiency. On the other hand, in the latter system, squirrel-cage induction generators (SCIGs), wound-rotor synchronous generators (WFSGs), and permanent magnet synchronous generators (PMSGs) are commonly used. While SCIGs and WFSGs offer the advantage of simple structure, they inherently have low torque / power density and low efficiency, and require a gearbox to match the wind turbine speed. These problems can be addressed in multi-pole PMSGs, but a full-power converter is unavoidable to provide VSCA voltage, thus significantly increasing the overall system cost and power losses.

[0052] Recently, DRPMGs operating at VSCA voltage have been developed for stand-alone wind power systems (e.g., Wang et al.'s "A Novel Dual-Rotor Bidirectional flux-modulation PM generator for stand-alone DC power supply"). IEEE Transactions on Industrial Electronics Volume 66, Issue 1, pp. 818-828, January 2019 (hereinafter referred to as Wang's References), and Chen et al.'s "Design and Analysis of a Variable-Speed ​​Constant-Amplitude Wind Generator for Stand-alone DC Power Applications". IEEE Transactions on Industrial Electronics. As described in Volume 70, Issue 8, pp. 7731-7742, August 2023 (hereinafter referred to as Chen's References), a schematic diagram of this wind power generation system is shown below. Figure 7C As shown. In particular, Figure 7CA schematic diagram illustrates a conventional system configuration using a diode rectifier with a DRPMG for stand-alone wind power generation, operating at VSCA voltage. In this system, one rotor is directly coupled to the wind turbine blades, eliminating the need for a gearbox. Additionally, another rotor is connected to a low-cost speed-dependent device (SPD), such as a cam-spring speed controller or a small high-speed servo motor. The angular position of this rotor can be adjusted such that the induced voltage in the windings remains constant (or approximately constant), i.e., operating at VSCA voltage. The winding voltage can then be easily rectified using a low-cost uncontrolled diode rectifier to charge the battery. However, various example embodiments note that in conventional DRPMGs (e.g., as described in the aforementioned Wang and Chen references), two sets of windings with different pole pairs are required, then connected in series in the stator. Those skilled in the art will understand that the pole pair number of a set of windings refers to half the total number of poles in the rotating fundamental magnetic field generated by the current flowing through that set of windings. In this respect, the requirement for dual windings complicates the winding design and results in suboptimal utilization of the stator slot conductor area, as each winding is limited to only a portion / section of the total available space.

[0053] Various exemplary embodiments introduce a novel DRPMG 200 that can be implemented in stand-alone wind power systems. Unlike conventional designs, the DRPMG 200 of this disclosure achieves VSCA voltage operation using only a single winding (single unified winding) in the stator 210. This design significantly improves the utilization of the permanent magnet (PM) magnetic field in the air gap, resulting in higher induced voltage, torque / power density, efficiency, and enhanced PM material utilization compared to similar products. The operating principles and analytical models of DRPMGs with single and double windings will be described below. A comprehensive finite element analysis (FEA) comparison between a conventional PMSG, this single-winding DRPMG 200, and a reference double-winding DRPMG will also be described later. Subsequently, for illustrative purposes, the prototype design and experimental testing of the DRPMG 200 of this disclosure will be described to validate the analysis.

[0054] Motor topology and operating principle Motor topology As mentioned above, Figure 1 and Figure 2The topologies of a reference DRPMG for stand-alone wind power generation and the DRPMG 200 of this disclosure are illustrated respectively. Both designs feature a stator, an outer rotor with a spoke array of permanent magnets (PMs) and steel segments, and an inner rotor with salient poles. In the example reference DRPMG, the reference DRPMG is a variant of the segmented tooth design described in the aforementioned Chen reference, employing conventional open stator slots and a slot-pole combination of 24 stator slots and 20 inner rotor poles. This configuration is known to enhance motor performance metrics, including torque / power density, power factor, and PM utilization. However, the reference DRPMG requires dual windings in the stator, one for the MGM and another for the VPM (see, for example, the aforementioned Chen reference, and Cao et al.'s "Decoupling Analysis of Brushless Dual-Mechanical-Port Dual-Electrical-Port Machines"). IEEE Transactions on Industrial Electronics. Volume 71, Issue 5, pp. 4361-4374, May 2024 (hereinafter referred to as the first Cao reference) and Cao et al.'s "Analysis of Contra-Rotating Brushless Integrated Flux-Modulation Machine with Open-Slot Structure for Wind Power Generation" IEEE Transactions on Industrial Electronics (journal) Volume 70, Issue 12, pp. 11934-11947, December 2023 (hereinafter referred to as the Second Cao Reference). Specifically, the MGM section includes the stator, MGM windings, outer rotor, and inner rotor, while the VPM section includes the stator, VPM windings, and outer rotor. Therefore, the stator slot conductor area must be divided between the MGM and VPM windings, and additional insulation is required between them, resulting in suboptimal utilization of the slot conductor area.

[0055] In contrast, various exemplary embodiments demonstrate that these conventional dual-winding systems can be unified into a single winding by matching the number of stator slots to the number of inner rotor poles. This unification allows the MGM and VPM motor portions to share the entire stator slot conductor area, significantly improving the utilization of the PM magnetic field and increasing the generator's power output. This is the first time a single-winding DRPMG has been developed for VSCA operation, which can be implemented, for example, in stand-alone wind power systems. The principles behind the performance improvements of this unified winding design will be described in further detail below.

[0056] The evolution from double-winding to single-winding For the sake of better understanding and without imposing limitations (e.g., not bound by theory), the evolution from a reference DRPMG with two sets of windings to the DRPMG 200 of this disclosure with a single set of windings 240 will now be described. According to field modulation theory, in the MGM portion of both generators (i.e., the reference DRPMG and the DRPMG of this disclosure), the number of pole pairs of the MGM windings... P MGM Number of pole pairs of PM in the external rotor P or and the number of salient poles of the inner rotor N ir Subject to the following relationships: (Formula 1) For the VPM section, the number of pole pairs of the VPM winding P VPM Number of pole pairs of PM in the external rotor P or and number of stator slots Q s should satisfy: (Formula 2) In various example embodiments, for instance, the DRPMG 200 of this disclosure may share the same number of PM pole pairs as the baseline DRPMG. P or =20) and the same number of stator slots ( Q s =24). However, they have a higher salient pole number in the inner rotor. N ir The differences are, for example, that the reference DRPMG has 18 internal rotor poles, while the DRPMG 200 of this disclosure can have 24 internal rotor poles. To distinguish between the two designs, the designation (x) is used, where x=1 refers to the reference DRPMG and x=2 refers to the DRPMG 200 of this disclosure. Therefore, and This means that in the DRPMG 200 disclosed herein, the number of salient poles of the inner rotor is equal to the number of stator slots, whereas they are different in the baseline design.

[0057] Therefore, the number of pole pairs of the MGM and VPM windings of the two generators can be derived. In the reference DRPMG, they are different, for example... P MGM (1) = 2 (i.e., the number of pole pairs of the MGM winding in the reference DRPMG is 2) and P VPM (1) = 4 (i.e., the number of pole pairs of the VPM winding in the reference DRPMG is 4), while in the DRPMG 200 of this disclosure they are always equal, for exampleP MGM (2)= P VPM (2) = 4. This difference stems from the inconsistency between the number of inner rotor poles and the number of stator slots in the two generators, as shown in formulas (1) and (2) above. Figure 8A and Figure 8B A schematic diagram illustrating the winding and rotor design / configuration of a reference DRPMG and the DRPMG 200 of this disclosure is shown. Specifically, in the DRPMG 200 of this disclosure, a set of windings 240 is mounted on the stator 210 via multiple stator slots 210, such that this set of windings 240 is shared by the MGM and VPM of the DRPMG 200 of this disclosure to generate an induced voltage. Furthermore, in the DRPMG 200 of this disclosure, the number of stator slots 214 on the stator 210 is equal to the number of rotor poles 224 on the inner rotor 220. In this respect, various exemplary embodiments have advantageously found that by matching the number of stator slots 214 to the number of inner rotor poles 224, a conventional dual-set winding can be unified into a single-set winding 240. In particular, various embodiments have found that by matching the number of stator slots 214 with the number of inner rotor poles 224, the number of pole pairs of the MGM and VPM windings is equal, thus the conventional MGM and VPM winding sets can be advantageously unified into a single winding 240 in the dual-rotor PM generator 200 according to various embodiments of the invention. In contrast, as Figure 8A As shown, in a traditional DRPMG, the number of stator slots on the stator differs from the number of rotor poles on the inner rotor. Therefore, in a traditional DRPMG, the number of pole pairs of the MGM and VPM windings is different, and thus the MGM and VPM winding sets cannot be unified into a single winding set in a traditional DRPMG.

[0058] In particular, the induced voltage frequency of the MGM winding f MGM It can be represented as: (Formula 3) in n MGM The equivalent mechanical angular velocity of the induced voltage in the MGM winding; n or and n ir These are the mechanical angular velocities of the outer and inner rotors, respectively. Simultaneously, the induced voltage frequency of the VPM winding... f VPM It can be represented as: (Formula 4) in n VPM It is the equivalent mechanical angular velocity of the induced voltage of the VPM winding.

[0059] According to formulas (3) and (4) above, when the inner rotor is stationary, i.e. n ir =0, in the reference DRPMG and the DRPMG of this disclosure, frequency f MGM and f VPM All equal to Therefore, MGM and VPM windings with different pole pair numbers can be connected in series in a reference DRPMG, while the DRPMG 200 of this disclosure can unify MGM and VPM windings with equal pole pair numbers into a single winding.

[0060] System Configuration Figure 9 A schematic diagram illustrating the configuration of a stand-alone wind power generation system operating at VSCA voltage is provided. For illustrative purposes, the case of a baseline / conventional DRPMG and the case of the DRPMG 200 of this disclosure according to various example embodiments are shown. It can be seen that the wind turbine 930 is directly coupled to the outer rotor, and the inner rotor is controlled by an SPD 320 (e.g., a small servo motor), as shown. In the baseline DRPMG, two sets of windings for the MGM and VPM motor sections are connected in series. The AC voltage connecting the windings is rectified to a DC voltage by a three-phase uncontrolled diode rectifier, which is used to charge the energy storage pool (e.g., a battery). In contrast, the DRPMG 200 of this disclosure uses a single set of windings 240 for the MGM and VPM motor sections, which can be directly connected to a diode rectifier 610. Due to fluctuations in wind speed and pressure causing variations in the speed of the wind turbine blades 930, stand-alone wind power generation systems require a nearly or nearly constant output voltage (i.e., VSCA voltage operation) to achieve efficient and safe charging. Figure 9 The VSCA voltage operation of the wind power generation system shown will be described below.

[0061] VSCA voltage operation To illustrate the VSCA voltage operation of the reference DRPMG and the DRPMG of this disclosure, the following conditions are assumed to calculate the induced voltage of the winding: 1) The inner rotor, held stationary by the servo motor, i.e. n ir =0; 2) Only the fundamental component is considered, while higher-order components are ignored.

[0062] In the MGM and VPM sections, the salient poles and stator teeth of the inner rotor act as flux modulators to modulate the PM field generated in the PM field of the outer rotor. However, these flux modulators are located on opposite sides of the outer rotor. Therefore, the fundamental component of the magnetomotive force (MMF) of the PM field in the MGM and VPM sections... F PM(θ,t) has a phase shift of π, and can be expressed as: (Formula 5) in θ This refers to the mechanical angular position within the external air gap. t For time, F PM1 The amplitude of MMF, ω or The mechanical angular velocity of the outer rotor is equal to... , This represents the initial mechanical angular position of the outer rotor, for the VPM section. k The value is 0 for the MGM portion. k The value is 1.

[0063] In the MGM section, the salient poles of the inner rotor act as flux modulators to modulate the PM field; therefore, the magnetic permeability of the MGM section... Λ MGM (θ) can be written as:

[0064] in Λ MGM0 and Λ MGM1 They are respectively Λ MGM The amplitudes of the DC constant component and the fundamental component of (θ), / 60 is the mechanical angular velocity of the inner rotor and because n ir =0 and equal to zero. θ ir0 This represents the initial mechanical angular position of the inner rotor. Then, the dominant magnetic flux density of the MGM portion in the outer air gap is determined. B MGM (θ,t) can be represented as: (Formula 7) in B Por and The MGM part is due to Λ MGM0 and Λ MGM1 The amplitude of the magnetic flux density obtained by modulation.

[0065] Due to the orthogonality of trigonometric functions, according to winding function theory, the induced voltage of the MGM winding... e MGM (t) can be calculated according to formula (8), where R og is the outer air gap radius. L s is the lamination length of the motor. NMGM (θ) is the winding function of the MGM winding as expressed by formula (9). N ph,MGM The number of series turns per phase of the MGM winding. k htMGM , k Por and For the corresponding harmonic order winding coefficient in the MGM winding, t MGM The motor period of the MGM winding is equal to GCD(Q) s , P MGM GCD is the greatest common divisor. θ MGM0 for N MGM The initial mechanical angular position of (θ). As shown in formula (8), the harmonics The contribution was factored by the corresponding factor These factors are amplified and are known as harmonic gear ratios.

[0066]

[0067] Considering Λ in the MGM section MGM0 Much smaller than Λ MGM1 (See the references for Wang and Chen above), and because P or and N ir Approximately large to generate high induced voltage and torque / power density, much smaller (For example, see the first Cao reference above), the first and third terms in formula (8) can be ignored in the MGM part. Therefore, the induced voltage of the MGM winding It can be simplified to: (Formula 10) Where E MGM1 for The amplitude. Then. Can be in vector form Rewritten as (Formula 11) In the VPM section, the stator teeth act as flux modulators for modulating the PM field; therefore, the magnetic permeability of the VPM section... Λ VPM θ can be written as: (Formula 12) Among them Λ VPM0 and ΛVPM1 They are respectively Λ VPM The amplitudes of the DC constant component and the fundamental component of θ. Then, the dominant magnetic flux density of the VPM component in the outer air gap. B VPM (θ,t) can be represented as: (Formula 13) in and These are the VPM parts due to Λ VPM0 and Λ VPM1 The amplitude of the magnetic flux density obtained by modulation.

[0068] Due to the orthogonality of trigonometric functions, according to winding function theory, the induced voltage of the VPM winding... It can be calculated using formula (14), where Let VPM winding function be expressed as formula (15). The number of series turns per phase of the VPM winding. , and For the corresponding harmonic order winding coefficient in the VPM winding, The motor period of the VPM winding is equal to GCD(Q) s ,P VPM From formula (14), it can be seen that harmonics The contribution of its gear ratio enlarge.

[0069]

[0070] Similarly, the induced voltage of the VPM winding It can be simplified to: (Formula 16) in for The amplitude. Then. Can be in vector form Rewritten as: (Formula 17) Therefore, the synthesized induced voltage of the generator for and The sum is:

[0071] Then, Can be in vector form Rewritten as: (Formula 19) and The electrical angle difference δ between them can be expressed as: (Formula 20) As can be seen from formula (20), the electrical angle difference δ depends only on the initial mechanical angular position of the inner rotor, which is adjusted by a speed-related device (e.g., a servo motor). Therefore, the synthesized induced voltage The amplitude range is from arrive ,at the same time E min and E max It is obtained when δ is an odd multiple of π and when it is 0.

[0072] Furthermore, when the external rotor speed ω or When changes occur, it can be achieved through... θ ir0 Adjusting the electrical angle difference δ to maintain E total Constant. This can be further achieved through... Figure 10 The vector diagram illustrates the induced voltage of the external rotor used for VSCA voltage operation at different speeds, where different speeds are indicated by apostrophes and the absence of apostrophes. It can be seen that the external rotor speed from ω... or Increase to This results in higher amplitude induced voltages in the MGM and VPM windings. However, by using two vectors... and ( and The angle is adjusted from δ to δ', and the resulting induced voltage at different speeds is... and The voltage falls on a voltage circle with a constant radius, meaning the amplitude of the synthesized induced voltage remains constant at different external rotor speeds. This is what is known as VSCA (Voltage-Sensitive Calibration) operation in stand-alone wind power systems.

[0073] improve Since the winding factors of the MGM and VPM windings are designed to be high and close to 1 in both the reference DRPMG and the DRPMG of this disclosure, they are simply considered to be equal, i.e. Then, according to formulas (18) and (20), when When equal to an odd multiple of π, the combined induced voltage of the reference DRPMG and the DRPMG of this disclosure E total Reaching the maximum value :

[0074] Assuming that the stator slot conductor area in the reference DRPMG is uniformly divided among the MGM and VPM windings, and that they have equal number of series turns per phase, i.e., their total number of turns, then... Half of, that is However, in the DRPMG 200 of this disclosure, the MGM and VPM windings share the entire stator slot conductor area in the form of a single unified winding 240, therefore Furthermore, due to ,harmonic gear ratio Harmonics in the part greater than MGM gear ratio Therefore, in formula (21), Less than This is because a higher gear ratio typically exhibits magnetic flux leakage and results in a lower magnetic flux density.

[0075] Then, the difference in maximum induced voltage between the DRPMG of this disclosure and the reference DRPMG. It can be calculated and has the following relationship: (Formula 22) when At that time, the first term of formula (22) is greater than 0. The second term of formula (22) is always positive because no harmonics are modulated in the VPM part. The magnetic flux density is greater than that of higher-order modulation harmonics. The magnetic flux density, the latter's gear ratio is Furthermore, the second term of formula (22) is actually the component contributed by the VPM part, because it is equal to the second term of formula (21) of the benchmark DRPMG. Therefore, when hour, Significantly greater than As an illustrative example and to impose limitations, Qs, P... or and The values ​​are 24, 20, and 18 respectively, which satisfy the condition. Therefore, compared to the benchmark DRPMG, the DRPMG 200 disclosed herein can exhibit significant improvements in induced voltage and torque / power density.

[0076] Performance Comparison To evaluate the performance of the DRPMG 200 of this disclosure with a single winding 240, a comparative study of independent wind power generation was conducted between a conventional surface-mounted PMSG, a reference DRPMG with a double winding, and the DRPMG 200 of this disclosure with a single winding 240.

[0077] For a fair comparison, all generators have the same number of stator slots, PM pole pairs, motor diameter, lamination length, slot fill factor, current density, and materials, such as... Figure 11 The summary is shown in Table I. In particular, Figure 11 A table (Table I) showing example key design parameters for the three generators studied above (i.e., PMSG, the baseline DRPMG, and the DRPMG 200 of this disclosure) is presented. The geometric parameters are then globally optimized using a non-dominated sorting genetic algorithm (NSGA-II) coupled with finite element analysis (FEA). The optimization aims to maximize the output power P at a rated external rotor speed of 200 r / min. out and in torque ripple T rp Minimize PM consumption V under the constraint of <10% PM The key design parameters for optimal design are summarized in... Figure 11 In Table I.

[0078] It should be noted that while various criteria (such as fixed PM volume or copper losses) can be used to optimize and compare different motor structures, using specific fixed values ​​for these criteria is not always appropriate or applicable in different motor designs. In this comparative study, a criterion based on a fixed current density without constraining the PM volume was adopted, and global optimization was used to automatically identify the optimal electrical and magnetic loads for each design. Finally, the performance of each design can be further evaluated in terms of output performance per PM volume and copper losses.

[0079] Unloaded field distribution The no-load field distribution (including magnetic flux density and magnetic field lines) of the above three generators under no-load conditions is as follows: Figure 12 As shown. The corresponding magnetic flux density in the outer air gap (unloaded air gap magnetic flux density), including waveform and harmonic spectrum, is shown below. Figure 13A and 13B As shown. In a conventional PMSG, the operating harmonic is the 20th harmonic, because the number of pole pairs P of the PM is... or The value is 20. In contrast, the reference DRPMG and the DRPMG of this disclosure integrate MGM and VPM sections, which utilize multiple operating harmonics to generate higher induced voltage and power. In the reference DRPMG and the DRPMG of this disclosure, the operating harmonic of the VPM section is mainly the 20th order (P20). or =20), the 4th and 44th harmonics However, due to the number of salient poles N of the inner rotor... ir They differ in the operating harmonics of the MGM portion. Specifically, the operating harmonics corresponding to the reference scheme are the second harmonic (…). The operating harmonics of the DRPMG 200 disclosed herein are the 4th harmonics. ).

[0080] While the reference DRPMG produces a slightly higher 20th harmonic amplitude (primarily due to its higher PM volume) and an additional 2nd harmonic, the DRPMG 200 of this disclosure exhibits a significantly higher 4th harmonic amplitude generated by both the MGM and VPM sections. Furthermore, in the DRPMG 200 of this disclosure, the MGM and VPM windings share the entire stator slot conductor area, whereas in the reference DRPMG, each winding uses only a portion / segment of the stator slot conductor area. This design improvement significantly amplifies the contribution of these modulation harmonics in the MGM and VPM sections of the DRPMG. Therefore, it can be seen that the DRPMG 200 of this disclosure produces a significantly higher induced voltage and torque / power density.

[0081] No-load induced voltage Figure 14A and Figure 14B The no-load induced voltage of the three generators described above at a rated external rotor speed of 200 r / min under no-load conditions is shown, including waveforms and harmonic spectra. It can be seen that the DRPMG 200 of this disclosure produces the highest fundamental component of the induced voltage among all generators. E 1, which is 83.3% and 82.0% higher than the conventional PMSG and the reference DRPMG, respectively. In the reference DRPMG, the amplitude of the 20th harmonic is reduced, and the stator slot conductor area is divided into two parts for the MGM and VPM windings, resulting in a less significant increase in induced voltage. In contrast, the significant increase in induced voltage of the DRPMG 200 disclosed herein is due to its single-winding design, which significantly enhances the utilization of stator slot conductor area and PM field.

[0082] To further consider the total number of turns per phase and PM volume V PM The influence of this factor is to divide the fundamental amplitude of the induced voltage by... and V PM It can be seen that the DRPMG 200 of this disclosure exhibits the highest conductor and PM utilization to generate induced voltage. Specifically, the DRPMG 200 of this disclosure... It is 14.4% and 59.4% higher than the conventional PMSG and the benchmark DRPMG, respectively. This further confirms the above statement. improve The design improvements of the winding design of this disclosure are analyzed in the subsection.

[0083] Figure 15A and Figure 15BThe induced voltage of the DRPMG 200 of this disclosure under different inner rotor positions and outer rotor speeds is shown. In particular, Figure 15A and Figure 15B The present disclosure shows graphs of the no-load induced voltage of the DRPMG 200 at different inner rotor positions and outer rotor speeds, including the relationship between the induced voltage amplitude and the inner rotor position at the rated outer rotor speed of 200 r / min. Figure 15A ) and the waveforms of the induced voltage at different external rotor speeds ( Figure 15B ).from Figure 15A It can be seen that at the rated external rotor speed of 200 r / min, the amplitude of the induced voltage varies with the position of the internal rotor, with the maximum and minimum values ​​respectively at... and This is obtained in a timely manner, which is in good agreement with the previous analysis relating to formulas (19) and (20). Therefore, as Figure 15B As shown, by changing the position of the inner rotor from Adjust to Even when the external rotor speed varies (reaching 2.7 times the rated speed), the induced voltage remains constant (or approximately constant). Therefore, the DRPMG 200 of this disclosure can operate with VSCA voltage at low cost and high reliability using an uncontrolled diode rectifier 610.

[0084] Figure 15C A graph showing the dynamic VSCA operation measured by the DRPMG 200 of this disclosure under load conditions is presented, including the outer rotor speed, inner rotor position, A-phase AC induced voltage, rectified DC voltage, and DC output current.

[0085] Torque performance Figure 16 The generator described above is shown at 5 A / mm 2 The torque waveform at the rated current density is shown. It can be observed that the DRPMG 200 of this disclosure generates output torque... T or In terms of performance, it is the best. Specifically, the average external rotor torque of the DRPMG 200 disclosed herein is 131.6 Nm, which is about 82% higher than the average torque of the conventional PMSG and the reference DRPMG. Taking into account copper losses and PM volume, the torque per copper loss and PM volume of the DRPMG 200 disclosed herein is about 17% and 117% higher than the conventional PMSG and the reference scheme, respectively.

[0086] Other performance Other performance characteristics of the aforementioned generators, such as power, losses, efficiency, power factor, and PM utilization, are also considered. Figure 17The comparisons and summaries are shown in Table II. It can be seen that, due to its significantly higher induced voltage (see Table II...),... Figure 14A and Figure 14B The DRPMG 200 of this disclosure offers over 80% more power compared to conventional PMSGs and benchmark DRPMGs. Regarding losses and efficiency, the total losses generated by the benchmark DRPMG and the DRPMG of this disclosure are at similar levels and higher than those of a conventional PMSG, primarily due to higher copper and iron losses. However, due to its significantly higher output power, the generator 200 of this disclosure achieves efficiencies that are 3.3% and 6.7% higher than those of conventional PMSGs and benchmark schemes, respectively. Furthermore, the DRPMG 200 of this disclosure can provide VSCA operation using a low-cost uncontrolled diode rectifier instead of the high-cost full-power controlled converter found in conventional PMSGs.

[0087] Experimental verification To validate the previous analysis and the single-winding design proposed in DRPMG, a prototype of the DRPMG 200 disclosed herein was built and tested. As an illustrative example, the design parameters of the prototype are detailed in [reference needed]. Figure 11 Table I is shown. Figures 18A to 18E Images of the prototype are shown, including its stator, outer rotor, inner rotor, PM and coils, as well as test fixtures for VSCA operation. Figure 18D The dSPACE system shown (corresponding to the reference above) Figure 4BThe control system 420 according to various embodiments of the invention controls an inverter to drive a servo motor I, which is connected to the outer rotor of the prototype via a torque sensor, to rotate at various speeds to simulate variations in wind input. Furthermore, the dSPACE system also manages a servo motor II, which is connected to the inner rotor of the prototype, to facilitate precise dynamic adjustment of the inner rotor's position based on the real-time speed of the outer rotor. In this regard, the position of the inner rotor 220 can be detected using a position sensor (e.g., an encoder or resolver) as the speed of the outer rotor 230 changes in response to variations in the rotatable device 930. This position sensor provides feedback to the dSPACE, which can be deployed with a standard PI (proportional-integral) controller. The PI controller can take the difference between the desired constant output voltage and the measured output voltage of the AC / DC rectifier detected by a voltage sensor as input. Using this voltage difference and feedback regarding the inner rotor's position, the PI controller in the dSPACE can generate a control signal and send it to the speed-dependent device 320 (e.g., the servo motor) to adjust the angular position of the inner rotor 220 accordingly. Therefore, this exemplary closed-loop control system dynamically adjusts the position of the inner rotor 220 to ensure consistent VSCA operation at different outer rotor speeds. The induced three-phase AC voltage is then converted to DC voltage using an uncontrolled diode rectifier. The DC output is then connected to an 80 Ω high-power ceramic resistor, which operates in parallel with a 33000 μF electrolytic capacitor as an energy storage reservoir.

[0088] During the no-load induced voltage test, servo motor I drove the outer rotor of the prototype at various speeds, while the inner rotor was fixed at a 180° electrical angle. Figure 18E The rectifier, capacitor, and resistor in the test setup are disconnected. Figure 19A and Figure 19B The no-load induced voltage measured at the rated speed of 200 r / min was compared with the induced voltage predicted by FEA, showing that they are in good agreement with a fundamental amplitude difference of 1.5%.

[0089] The average load torque of the outer rotor was measured and compared with the value predicted by the FEA. In this test, the prototype's armature windings were powered by an inverter controlled by the dSPACE system, and the inner rotor was locked at 180 electrical degrees. In this setup, Figure 18E The servo motor I shown has been replaced with a magnetic power brake and used as a load. Figure 20A and Figure 20B The figure shows the measured and simulated torque under different current angles and amplitudes. In particular, Figure 20A and Figure 20B A graph showing the external rotor torque is presented, including the relationship between torque and current angle at 20A. Figure 20AAnd the relationship between torque and current amplitude at zero current angle ( Figure 20B To ensure safe operation within the limitations of the torque sensor (HBM-T21WN, nominal torque: 100 Nm, accuracy: 0.2 Nm), the current was tested up to 20A, and the measured output torque reached approximately 104.5 Nm. It can be seen that good agreement can be found between the measured and simulated average output torque.

[0090] To further verify the voltage operation of the VSCA through experiments, the measured and simulated (FEA predicted) voltage envelopes of the no-load AC induced voltage were compared at the rated external rotor speed of 200 r / min. The results are as follows: Figure 21A and Figure 21B As shown. In this test, the outer rotor, driven by servo motor I, maintained a constant speed of 200 r / min, while the inner rotor, driven by servo motor II, rotated at a low speed of 1 r / min. The results show that, although there are slight differences mainly due to manufacturing defects and controlled speed variations of the two rotors during the experiment, the range of the measured and simulated induced voltage is approximately 30V to 78V. Furthermore, dynamic VSCA operation under load conditions was evaluated, with the outer rotor speed varying from 150 r / min to 200 r / min and back to 200 r / min. Notably, the position of the inner rotor was adjusted accordingly to maintain a nearly constant output DC voltage despite the variation in the outer rotor speed. This effectively demonstrates the VSCA voltage operation of the generator 200 disclosed herein in actual testing.

[0091] Therefore, according to various exemplary embodiments of the present invention, a DRPMG 200 with a single winding 200 was developed and compared with a benchmark DRPMG with a double winding in a stand-alone wind power generation system operating under VSCA conditions. By adjusting the position of the inner rotor, the induced AC voltage can be easily rectified using a low-cost uncontrolled diode rectifier, while maintaining a constant voltage output at different wind speeds, which is an important feature for stand-alone applications in remote areas.

[0092] The analysis above shows that when the number of stator slots With the number of poles of the inner rotor N ir During matching, a single-set winding design can be efficiently implemented according to various example embodiments. Furthermore, analysis and case studies demonstrate that this single-set winding design offers significant performance improvements, particularly for the number of pole pairs on the outer rotor. P or Satisfying the slot-pole relationship DRPMG.

[0093] Compared to conventional PMSGs, the DRPMG 200 of this disclosure offers approximately 80% more torque / power density, 3.3% higher efficiency, and 17% improved PM utilization. Compared to a baseline DRPMG with dual windings, it offers approximately 80% more torque / power density, 6.7% higher efficiency, and a significant 117% improvement in PM utilization. These significant performance enhancements are attributed to the higher utilization of stator slot conductor area and PM field achieved through the DRPMG 200 design with a uniform single winding. Therefore, various exemplary embodiments provide an improved DRPMG design, which can be implemented, for example, in stand-alone wind power generation, and provide useful / practical design guidance for DRPMGs with a single winding. As described above, a prototype of the DRPMG 200 of this disclosure was constructed and experimentally tested to validate the analysis.

[0094] While embodiments of the invention have been specifically shown and described with reference to specific examples, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims. Therefore, the scope of the invention is indicated by the appended claims, and all changes within the meaning and equivalents of the claims are thus intended to be covered.

Claims

1. A dual-rotor permanent magnet generator, comprising: A stator with multiple stator slots; An internal rotor with multiple rotor poles; An outer rotor comprising multiple permanent magnets is arranged between the stator and the inner rotor; as well as A set of windings is mounted on the stator through the plurality of stator slots, such that the set of windings is shared by the magnetic gear motor and the vernier permanent magnet motor of the dual rotor permanent magnet generator to generate an induced voltage.

2. The dual-rotor permanent magnet generator according to claim 1, wherein the number of stator slots on the stator is equal to the number of rotor poles on the inner rotor.

3. The dual-rotor permanent magnet generator according to claim 1 or 2, wherein... The stator, the outer rotor, the inner rotor, and the set of windings together constitute the magnetic gear motor. The stator, the outer rotor, and the set of windings together constitute the vernier permanent magnet motor.

4. The dual-rotor permanent magnet generator according to any one of claims 1 to 3, wherein the stator, the inner rotor, and the outer rotor are arranged coaxially around a common axis.

5. The dual-rotor permanent magnet generator according to any one of claims 1 to 4, wherein the set of windings is connected to an AC / DC rectifier for rectifying the induced voltage of the set of windings generated during operation to charge the energy storage device.

6. The dual-rotor permanent magnet generator according to any one of claims 1 to 5, wherein one of the inner rotor and the outer rotor is connected to and controlled by a speed-related device, and the other of the inner rotor and the outer rotor is connected to and controlled by a rotatable device configured to be rotatable by an external kinetic energy source.

7. A power generation system, comprising: Dual-rotor permanent magnet generator, including: A stator with multiple stator slots; An internal rotor with multiple rotor poles; An outer rotor comprising multiple permanent magnets is arranged between the stator and the inner rotor; and A set of windings is mounted on the stator through the multiple stator slots, such that the set of windings is shared by the magnetic gear motor and the vernier permanent magnet motor of the dual rotor permanent magnet generator to generate induced voltage; A speed-related device is connected to one of the inner rotor and the outer rotor for controlling it.

8. The power generation system according to claim 7, wherein the number of stator slots on the stator is equal to the number of rotor poles on the inner rotor.

9. The power generation system according to claim 7 or 8, wherein The stator, the outer rotor, the inner rotor, and the set of windings together constitute the magnetic gear motor. The stator, the outer rotor, and the integrated winding together constitute the vernier permanent magnet motor.

10. The power generation system according to any one of claims 7 to 9, wherein the stator, the inner rotor, and the outer rotor are arranged coaxially about a common axis.

11. The power generation system according to any one of claims 7 to 10, wherein the other of the inner rotor and the outer rotor is coupled to and controlled by a rotatable device configured to be rotated by an external kinetic energy source.

12. The power generation system according to any one of claims 7 to 11, further comprising a control system communicatively connected to the speed-dependent device for operating the power generation system, wherein the control system is configured to control the speed-dependent device to control the angular position of one of the inner rotor and the outer rotor based on the speed of the other of the inner rotor and the outer rotor to perform variable speed constant amplitude (VSCA) voltage operation associated with the induced voltage.

13. The power generation system according to any one of claims 7 to 12, further comprising: An AC / DC rectifier connected to the set of windings; as well as An energy storage device connected to the AC / DC rectifier. The AC / DC rectifier is configured to rectify the induced voltage of the set of windings generated during operation in order to charge the energy storage device.

14. The power generation system according to any one of claims 7 to 13, wherein the AC / DC rectifier is a diode rectifier.

15. A method of operating a power generation system according to any one of claims 7 to 14, the method comprising: Using the speed-dependent device of the power generation system, the angular position of one of the inner rotor and the outer rotor is controlled based on the speed of the other to perform variable speed constant amplitude (VSCA) voltage operation related to the induced voltage.

16. A method for manufacturing a dual-rotor permanent magnet generator, comprising: Provides a stator with multiple stator slots; Provides an internal rotor with multiple rotor poles; An outer rotor comprising a plurality of permanent magnets is provided, the outer rotor being arranged between the stator and the inner rotor; as well as A set of windings is installed on the stator through the multiple stator slots, such that the set of windings is shared by the magnetic gear motor and the vernier permanent magnet motor of the dual rotor permanent magnet generator to generate induced voltage.

17. The method of claim 16, wherein the number of stator slots on the stator is equal to the number of rotor poles on the inner rotor.

18. The method according to claim 16 or 17, wherein The stator, the outer rotor, the inner rotor, and the set of windings together constitute the magnetic gear motor. The stator, the outer rotor, and the set of windings together constitute the vernier permanent magnet motor.

19. The method according to any one of claims 16 to 18, wherein the stator, the inner rotor, and the outer rotor are arranged coaxially about a common axis.

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