Flywheel energy storage double-rotor double-stator permanent magnet brushless phase-modulator system and control method thereof

Abstract

The application relates to a flywheel energy storage double-rotor double-stator permanent-magnet brushless phase modifier system, which mainly comprises a flywheel energy storage device, a double-rotor double-stator permanent-magnet brushless phase modifier and a converter. Two rotors and two stators are arranged in the phase modifier, a power winding is arranged in the outer power stator, and a control winding is arranged in the inner control stator; the flywheel is connected with the inner modulation rotor, the power winding is connected with a power grid, and the control winding is connected with the power grid through a back-to-back converter. The control winding realizes energy storage and release of the flywheel and reactive and active regulation of the phase modifier through the converter. The flywheel can be regulated in a large speed range, and the kinetic energy utilization rate is high; the phase modifier integrates the functions of a traditional phase modifier and a magnetic variable speed gear, adopts permanent magnet excitation, has high integration and power density, and is low in cost; the power of the control winding is only the slip power of the phase modifier, the power of the converter is reduced accordingly, and the system cost is further reduced.

Description

Technical Field

[0001] This invention belongs to the field of high inertia phase shifter technology, specifically relating to a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system and its control method. Background Technology

[0002] With the significant increase in the proportion of new energy power generation such as wind and solar power, the voltage support, inertia support, and frequency regulation capabilities of the power system have been continuously weakened, posing a serious challenge to its safe and stable operation. Currently, new distributed synchronous condensers have become key equipment for improving the voltage and inertia support of new energy power plants, playing a crucial role in enhancing the short-circuit ratio and dynamic voltage support of these plants. However, the rotational inertia of the synchronous condenser itself is relatively small, resulting in insufficient inertia support capability for new energy power plants. To increase the rotational inertia of the new distributed synchronous condenser system, flywheels are typically added.

[0003] The inertial time constant of a synchronous condenser system is proportional to its mechanical energy storage. To reduce equipment size and operating losses, the synchronous condenser + variable speed gearbox + flywheel scheme has received increasing attention and is a research hotspot in this field. This is because the flywheel can release or absorb mechanical energy over a wide speed range, significantly improving inertia support capabilities. It can also participate in the primary frequency regulation of the system, giving the variable speed flywheel energy storage synchronous condenser system superior voltage stabilization, inertia support, and frequency regulation capabilities.

[0004] However, currently, synchronous condensers and variable speed gearboxes are usually designed and assembled independently, resulting in large and costly systems with low integration. In addition, whether it is a synchronous or asynchronous synchronous condenser, the rotor windings require complex brush devices, which are difficult to maintain and have a high failure rate during long-term operation.

[0005] Therefore, developing a new type of synchronous condenser technology that integrates the functions of a synchronous condenser and a variable speed gearbox without a brush device is an urgent problem to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to at least solve one or more of the aforementioned problems existing in the prior art. In other words, one of the objectives of this invention is to provide a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system and its control method that meet one or more of the aforementioned requirements.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase condenser system, comprising a dual-rotor dual-stator permanent magnet brushless phase condenser, a flywheel, and a converter, wherein... The dual-rotor, dual-stator permanent magnet brushless synchronous condenser includes an inner control stator, an inner modulation rotor, an outer permanent magnet rotor, and an outer power stator, arranged coaxially from the inside out. Both the outer permanent magnet rotor and the inner modulation rotor can rotate freely relative to the outer power stator and the inner control stator, respectively. The external permanent magnet rotor is equipped with permanent magnets of the first pole pair number, which are used to generate the first pole pair number of excitation magnetic fields; The internal modulation rotor is connected to the flywheel and forms an inertial body rotating at the same speed. Several sets of magnetic blocks are spaced apart on the internal modulation rotor to modulate the excitation magnetic field. The external power stator is equipped with power windings, which are configured as the first pole pair. The internal control stator is provided with a control winding, which is configured as a second pole pair. The sum of the number of the first pole pairs and the number of the second pole pairs is equal to the number of magnetic blocks, and the number of the first pole pairs and the number of the second pole pairs are not equal; The modulation forms a first pole pair main magnetic field component corresponding to the power winding and a second pole pair modulated harmonic magnetic field component corresponding to the control winding.

[0008] The power winding is connected to the grid side of the synchronous condenser system to serve as the main channel for active and reactive power interaction with the grid side. The control winding is connected to the grid side through the converter to regulate the rotational speed of the inertial body and the active and reactive power interaction.

[0009] In a preferred embodiment, the internal modulation rotor includes several sets of fan-shaped magnetic blocks arranged at intervals along the circumference and non-magnetic blocks disposed between two adjacent magnetic blocks. The magnetic blocks and non-magnetic blocks are connected end to end to form a ring, so as to form a periodic change in magnetic permeability in the circumference of the internal modulation rotor.

[0010] In a preferred embodiment, the external power stator has a plurality of first salient pole teeth, and a first stator slot is formed between two adjacent first salient pole teeth, and the power winding is arranged in the first stator slot; The internal control stator has multiple second salient pole teeth, and a second stator slot is formed between two adjacent second salient pole teeth. The control winding is arranged in the second stator slot.

[0011] As a further preferred embodiment, the power winding is formed by connecting multiple power coils, and the control winding is formed by connecting multiple control coils. Both the power coils and the control coils adopt a distributed winding structure.

[0012] In a preferred embodiment, the external permanent magnet rotor includes an annular magnetic yoke and permanent magnets respectively disposed on the outer and inner sides of the annular magnetic yoke. The permanent magnets located on the outer side of the annular magnetic yoke are used for coupling with the air gap magnetic field corresponding to the power winding, and the permanent magnets located on the inner side of the annular magnetic yoke are used for coupling with the air gap magnetic field corresponding to the control winding via the internally modulated rotor.

[0013] In a preferred embodiment, permanent magnets are uniformly arranged circumferentially on both the outer and inner sides of the annular magnetic yoke. Each pair of permanent magnets includes two permanent magnets with opposite magnetization directions and radial magnetization, and the magnetization directions of adjacent permanent magnets are opposite.

[0014] As a preferred embodiment, the converter is a back-to-back converter.

[0015] As a further preferred embodiment, the back-to-back converter consists of two three-phase full-bridge power circuits and an energy storage capacitor, with the energy storage capacitor arranged in the DC bus between the two three-phase full-bridge power circuits.

[0016] As a preferred implementation, the rated capacity of the converter is 20%-30% of the rated capacity of the synchronous condenser system.

[0017] On the other hand, the present invention also provides a control method for a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system, comprising: Obtain the rate of change of the flywheel's rotational speed; When the rate of change of rotational speed is greater than zero, the flywheel is determined to be in a speed-up energy storage state. The converter is controlled to adjust the current frequency input to the control winding in the positive direction so that the external permanent magnet rotor can absorb power from the grid side through the synchronous condenser system. When the rate of change of rotational speed is less than zero, the flywheel is determined to be in a state of deceleration and energy release. The converter is controlled to adjust the frequency of the current input to the control winding in the negative direction so that the external permanent magnet rotor can output power to the grid side through the synchronous condenser system.

[0018] Compared with the prior art, the flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system and its control method provided by the present invention have the following beneficial effects: The dual-rotor, dual-stator permanent magnet brushless synchronous condenser system of this invention combines flywheel energy storage with a synchronous condenser, effectively increasing the system's rotational inertia. This enhances the power system's voltage support, inertia support, and frequency regulation capabilities. Furthermore, it eliminates the need for brushes, resulting in high structural integration, high power density, low cost, and significantly reduced maintenance costs and workload. The flywheel is directly connected to the internal modulation rotor. When the power winding current frequency remains constant, the flywheel's energy storage and release, as well as the reactive and active power control of the synchronous condenser, can be achieved by adjusting controllable variables such as the frequency, magnitude, and phase angle of the control winding current, thus fully utilizing the flywheel's kinetic energy. In addition, the converter driving the control winding has the same power as the motor's slip power, effectively reducing converter costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system according to the present invention; Figure 2 This is a schematic diagram of the structure of the dual-rotor, dual-stator permanent magnet brushless camera of the present invention.

[0020] Reference numerals in the attached diagram: Dual-rotor dual-stator permanent magnet brushless synchronous condenser-100, inner control stator-110, control winding-111, inner modulation rotor-120, outer permanent magnet rotor-130, annular magnetic yoke-131, permanent magnet-132, outer power stator-140, power winding-141, flywheel-200, converter-300, grid side-400. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of the invention. Various processes or components may be appropriately omitted, substituted, or added to the various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0023] An embodiment of the present invention provides a flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system, the structural schematic diagram of which is shown below. Figure 1 As shown, it includes a dual-rotor, dual-stator permanent magnet brushless synchronous condenser 100, a flywheel 200, and a converter 300, and also includes a connected grid side 400.

[0024] Please see Figure 2 The dual-rotor, dual-stator permanent magnet brushless synchronous condenser 100 includes an external power stator 140, an external permanent magnet rotor 130, an internal modulation rotor 120, and an internal control stator 110, which are used to realize the interaction of active and reactive power on the grid side.

[0025] In one specific structure, an inner control stator 110, an inner modulation rotor 120, an outer permanent magnet rotor 130, and an outer power stator 140 are formed in a coaxial nested structure from the inside to the outside along the radial direction. The outer power stator 140, the outer permanent magnet rotor 130, the inner modulation rotor 120, and the inner control stator 110 are coaxially arranged around the same axis, and both the outer permanent magnet rotor 130 and the inner modulation rotor 120 can rotate freely around the axis relative to the outer power stator 140 and the inner control stator 110.

[0026] The inner modulation rotor 120 is directly connected to the flywheel 200. The two rotate at the same speed and together form an inertial body. The outer permanent magnet rotor 130 is not connected to any additional load device.

[0027] Since the flywheel 200 rotates at the same speed as the internal modulation rotor 120, the change in the mechanical kinetic energy of the flywheel 200 can be reflected in the dual-rotor dual-stator permanent magnet brushless synchronous condenser 100 through the change in the rotational speed of the internal modulation rotor 120, thereby enabling the flywheel 200 to participate in energy storage, energy release and grid-side power regulation.

[0028] Specifically, the flywheel 200 can be a steel disc.

[0029] The external permanent magnet rotor 130 includes an annular magnetic yoke 131 and two magnets disposed on the annular magnetic yoke 131. p For sector-shaped permanent magnet 132, among which p It is the first pole logarithm.

[0030] Specifically, the outer side of the annular magnetic yoke 131 is circumferentially arranged p For the permanent magnet 132, and the inner side of the annular magnetic yoke 131 is arranged circumferentially. p For permanent magnet 132.

[0031] The permanent magnet 132 located outside the annular magnetic yoke 131 is used to couple with the air gap magnetic field on one side of the external power stator 140, and the permanent magnet 132 located inside the annular magnetic yoke 131 is used to couple with the air gap magnetic field on one side of the internal control stator 110 via the internal modulation rotor 120, thereby providing a common excitation source for the power port and the control port.

[0032] In one arrangement of permanent magnets 132, the permanent magnets 132 on the outer and inner sides of the annular magnetic yoke 131 are uniformly arranged circumferentially. Each pair of permanent magnets 132 includes two permanent magnets 132 with opposite magnetization directions, and each permanent magnet 132 is radially magnetized; the magnetization directions of two adjacent permanent magnets 132 are opposite.

[0033] The permanent magnets 132 located on the inner and outer sides of the annular magnetic yoke 131 at the same circumferential position can be arranged with their center lines coinciding, and the magnetization direction of the inner and outer permanent magnets 132 at the same circumferential position can be consistent.

[0034] The aforementioned radial magnetization and alternating circumferential arrangement enable the outer permanent magnet rotor 130 to form alternating circumferential magnetic poles, thereby generating an excitation magnetic field corresponding to the number of pole pairs of the power winding 141.

[0035] Several sets of magnetic blocks are arranged at intervals along the circumference of the internal modulation rotor 120. Non-magnetic blocks are arranged between two adjacent magnetic blocks. The magnetic blocks and non-magnetic blocks are arranged alternately in the circumference and connected end to end to form a ring structure, so that the circumferential magnetic permeability of the internal modulation rotor 120 changes periodically.

[0036] The periodic change in magnetic permeability is used to modulate the excitation magnetic field provided by the external permanent magnet rotor 130 and couple the mechanical motion of the internal modulation rotor 120 with the spatial harmonics of the air gap magnetic field.

[0037] The external power stator 140 has multiple first salient pole teeth, and a first stator slot is formed between two adjacent first salient pole teeth. The power winding 141 is arranged in the first stator slot.

[0038] The power winding 141 can be formed by connecting multiple power coils according to the winding connection method of a three-phase AC motor, and adopts a distributed winding structure. By employing a corresponding winding method, the power winding 141 is configured with a first pole pair number... p Used to modulate the outer permanent magnet rotor 130 and the inner modulation rotor 120 to form p Corresponding to the principal magnetic field component.

[0039] The internal control stator 110 has multiple second salient pole teeth, and a second stator slot is formed between two adjacent second salient pole teeth. The control winding 111 is arranged in the second stator slot.

[0040] The control winding 111 can be formed by connecting multiple control coils according to the winding connection method of a three-phase AC motor, and adopts a distributed winding structure. By employing a corresponding winding method, the control winding 111 is configured with a second pole pair number... q Used to modulate with the internal modulation rotor 120 q The corresponding harmonic magnetic field components of the polar modulation.

[0041] Thus, the external power stator 140 and the internal control stator 110 form two electrical ports through slot windings, so that the power channel and the control channel are structurally separated.

[0042] In the electromagnetic coupling path, the permanent magnet 132 and the magnetic yoke first form the excitation magnetic field of the outer permanent magnet rotor 130; the magnetic block and the non-magnetic block then modulate the excitation magnetic field through the circumferential periodic magnetic permeability.

[0043] The number of magnetic blocks in the internal modulation rotor 120 is N m First pole logarithm p With the second pole logarithm q All are positive integers and satisfy the following conditions: N m = p + q And p≠q. Under this pole-log relation, the modulated magnetic field forms a shape corresponding to the power winding 141. p The main magnetic field components, and those corresponding to control winding 111 q The polarity modulated harmonic magnetic field component.

[0044] By making N m equal p and q The sum of these two states means that the inner modulation rotor 120 can control the outer permanent magnet rotor 130. p The excitation magnetic field is modulated to control winding 111. q For the polar harmonic magnetic field components, while retaining the components corresponding to the power winding 141 p The main magnetic field component of the pole.

[0045] In the power path, the power winding 141 is directly connected to the grid, serving as the main channel for active and reactive power interaction between the synchronous condenser system and the grid; the control winding 111 is connected to the grid via the back-to-back converter 300, serving as the control channel for adjusting the frequency, amplitude, and phase angle of the current in the control winding 111.

[0046] Specifically, the magnetic field generated by the permanent magnet 132 in the outer permanent magnet rotor 130 is modulated by the magnetic guide block in the inner modulation rotor 120 to generate a main magnetic field component and a harmonic magnetic field component, which are decoupled from each other. Among them, the main magnetic field component is linked with the power winding 141, and the harmonic magnetic field component is linked with the control winding 111. Through this correspondence of magnetic field components, the power winding 141 and the control winding 111 can form the main power channel and the control adjustment channel, respectively, so that the main power interaction and control-side adjustment can be realized in the same dual-rotor dual-stator permanent magnet brushless synchronous condenser 100.

[0047] The aforementioned magnetic field path and power path work together to enable the excitation magnetic field of the external permanent magnet rotor 130 to be coupled to the power winding 141 and the control winding 111 via the internal modulation rotor 120, respectively. The power winding 141 undertakes the main power interaction on the grid side, and the control winding 111 undertakes the control-side power interaction required for the speed regulation and active and reactive power regulation of the flywheel 200.

[0048] The power winding 141 is directly connected to the power grid, and the control winding 111 is connected to the power grid via the converter 300.

[0049] At this point, only a partial power converter is needed to achieve variable speed constant frequency reactive and active power control. The power winding 141 is directly connected to the power grid and serves as the main channel for active and reactive power flow, realizing energy exchange and transfer between the synchronous condenser and the power grid.

[0050] The control winding 111 is connected to the power grid through the converter 300. The frequency, amplitude and phase angle of the current in the control winding 111 are adjusted to realize the energy storage and release of the flywheel 200 and the real-time control of the active and reactive power of the synchronous condenser.

[0051] In some specific embodiments of the present invention, the converter 300 is a back-to-back converter 300, which is connected to the power grid using PWM control.

[0052] As an example, the back-to-back converter 300 consists of two three-phase full-bridge power circuits and an energy storage capacitor. One of the three-phase full-bridge power circuits is located on the control winding 111 side, and the other three-phase full-bridge power circuit is located on the grid side. The energy storage capacitor is arranged in the DC bus between the two three-phase full-bridge power circuits.

[0053] In one embodiment, when the control winding 111 and the power winding 141 are respectively supplied with frequencies of... f c , f p When a current flows through it, the rotational angular velocity of the magnetic field is generated. oh c , oh p They are respectively: .

[0054] External permanent magnet rotor 130 p The excitation magnetic field provided by the permanent magnet 132, after being modulated by the magnetic field of the inner modulation rotor 120, forms effective magnetic field components on the side of the outer power stator 140 and the side of the inner control stator 110, wherein... p The main magnetic field component is used to link with the power winding 141. q The pole-modulated harmonic magnetic field component is used to link with the control winding 111. The magnetic field component specifically includes... p The fundamental magnetic field of the opposite pole (providing the excitation magnetic field for power winding 141) and q (Right now N m - p The harmonic magnetic field of the opposite pole (provides the excitation magnetic field for the control winding 111).

[0055] Based on the working principle of magnetic speed-changing gears, we can conclude that: .

[0056] In the formula, oh i The rotational angular velocity of the external permanent magnet rotor 130 is, and oh i = oh p , oh m G is the rotational angular velocity of the internal modulation rotor 120, and G is the transmission ratio.

[0057] Furthermore, the angular velocity of the internally modulated rotor 120 can be obtained. ohm and rotational speed n m They are respectively .

[0058] In addition, due to oh i = oh p The rotational speed of the external permanent magnet rotor 130 n i for: .

[0059] When the power winding current frequency is 141 f p When the grid frequency remains constant, the external permanent magnet rotor 130 will also run at a constant speed. At this time, only the frequency of the current in the control winding 111 needs to be adjusted. f c This allows you to adjust the speed of the internal modulation rotor 120, which is the speed of the flywheel 200.

[0060] When DC current is applied to the control winding 111, the stable speed of the internal modulation rotor 120 is the synchronous speed of the dual-rotor, dual-stator permanent magnet brushless synchronous condenser 100: .

[0061] In the formula, oh m0 and n m0 These are synchronous angular velocity and synchronous rotational speed, respectively.

[0062] Furthermore, the slip rate of the dual-rotor, dual-stator permanent magnet brushless phase converter 100 is defined. s for: .

[0063] Based on the operating principle of a doubly-fed induction generator, the electromagnetic power of the power winding 141 can be obtained. P p (i.e., adjusting camera power) and controlling the electromagnetic power of winding 111 P q for: .

[0064] Therefore, similar to traditional brushless doubly fed motors, the control winding 111 of the dual-rotor dual-stator permanent magnet brushless synchronous condenser 100 only needs to provide slip power when operating at variable speed and constant frequency.

[0065] Since the control winding 111 and the back-to-back converter 300 are responsible for the slip ratio sThe relevant slip power of the back-to-back converter 300 can be configured as a portion of the rated capacity of the synchronous condenser system. For example, the rated capacity of the converter 300 is 20%-30% of the rated capacity of the synchronous condenser system.

[0066] As can be seen from the above structure and formula relationships, the flywheel 200 and the inner modulation rotor 120 are connected at the same speed to form an inertial body, so that the energy storage state of the flywheel 200 can be mapped to the rotational speed state of the inner modulation rotor 120; the magnetic and non-magnetic blocks in the inner modulation rotor 120 form periodic magnetic permeability changes, which modulate the permanent magnet excitation magnetic field of the outer permanent magnet rotor 130, forming a magnetic field that links with the power winding 141 and the control winding 111 respectively. p The principal magnetic field components and q The polarity modulates the harmonic magnetic field components; the power winding 141 is directly connected to the power grid to form the main electrical port for active and reactive power interaction, and the control winding 111 is connected to the power grid via the back-to-back converter 300 to form the control electrical port; the control winding 111 and the back-to-back converter 300 bear the slip power and regulate the current frequency of the control winding 111, so that the speed, active power interaction and reactive power interaction of the internally modulated rotor 120 and flywheel 200 can be regulated.

[0067] Therefore, a 20%-30% converter 300 capacity configuration can serve flywheel 200 energy storage / release, synchronous condenser active / reactive power control, grid-side voltage support, inertia support, and frequency regulation support within a supported slip power range.

[0068] Based on the system structure of the above-mentioned flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system, one embodiment of this application also provides a control method for the flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system, which can be executed by the controller or converter control unit in the system.

[0069] The method includes the following steps: First, obtain the rate of change of the flywheel's rotational speed.

[0070] The speed of the flywheel and the internally modulated rotor exists in the following different states: when f q When the current is 0, a direct current is applied to the control winding, the rotational speed of the magnetic field generated by the control winding is zero, and the flywheel speed is... n m = n m0 ;when f q When >0, n m (or oh m )and oh c same direction,n m > n m0 ;when f q When <0, n m (or oh m )and oh c In the opposite direction, n m < n m0 .

[0071] Define the mechanical power of the internally modulated rotor as: P m The mechanical power of the external permanent magnet rotor is P i Based on the rotational speed and acceleration of the internal modulation rotor and flywheel, and neglecting losses, the flywheel energy storage synchronous condenser system exhibits the following power flow states: When the rate of change of speed of the internally modulated rotor and flywheel is d n m / d t When the value is 0, the flywheel is in standby mode. f q It remains unchanged.

[0072] When d n m / d t When the value is greater than 0, the flywheel is determined to be in a speed-up energy storage state, and the energy storage increases ( P m <0), the external permanent magnet rotor draws power from the grid via a synchronous condenser ( P i >0), the converter adjusts the frequency of the control current input to the control winding in the positive direction (d). f q / d t >0), causing a positive adjustment of the current frequency on the control winding side; the corresponding control winding q The polarity modulation harmonic magnetic field changes with the adjustment of the current frequency, and the magnetic field modulation relationship is participated in by the magnetic and non-magnetic blocks in the inner modulation rotor, so that the inner modulation rotor and the flywheel connected at the same speed maintain the trend of increasing speed and storing energy.

[0073] At this point, there are three possible scenarios: like n m > n m0 Then the control winding outputs power to the power grid. P q <0); liken m = n m0 Then there is no power exchange between the control winding and the power grid. P q =0); like n m < n m0 Then the control winding absorbs power from the grid ( P q >0).

[0074] When d n m / d t When <0, the flywheel is determined to be in a state of deceleration and energy release, and the stored energy decreases ( P m >0), the external permanent magnet rotor outputs power to the grid via the synchronous condenser ( P i <0), the converter adjusts the frequency of the control current input to the control winding in the negative direction (d). f q / d t <0, causing a negative adjustment of the current frequency on the control winding side; the corresponding control winding q The polarity modulation harmonic magnetic field changes with the adjustment of the current frequency, and the magnetic field modulation relationship is participated in by the magnetic and non-magnetic blocks in the inner modulation rotor, so that the inner modulation rotor and the flywheel connected at the same speed maintain the running trend of deceleration and energy release.

[0075] At this point, there are three possible scenarios: like n m > n m0 Then the control winding absorbs power from the grid ( P q >0); like n m = n m0 Then there is no power exchange between the control winding and the power grid. P q =0); like n m < n m0 Then the control winding outputs power to the power grid. P q <0).

[0076] In the aforementioned control process, positive or negative adjustments to the frequency of the control winding side current are used to change the speed of the internal modulation rotor and flywheel. The amplitude and phase angle of the control winding side current can also be used to coordinate the adjustment of active and reactive power between the dual-rotor, dual-stator permanent magnet brushless synchronous condenser and the power grid. The power winding is directly connected to the power grid and serves as the main power channel, while the control winding is connected to the power grid via a back-to-back converter and serves as the slip power regulation channel. Therefore, the system can achieve active power regulation on the grid side during flywheel energy storage and release, and provide reactive power support through the synchronous condenser function, ultimately enhancing the voltage support, inertia support, and frequency regulation capabilities of the power system.

[0077] Through the structure and control method described in this application, the system can adjust the flywheel speed with a relatively small converter capacity configuration, and achieve active and reactive power interaction through the cooperation of the power winding and the control winding. Voltage support mainly relies on the reactive power regulation capability involving the power winding and the control winding, while inertia support and frequency regulation capability mainly rely on the same-speed inertial body formed by the flywheel and the internally modulated rotor and its energy storage / release control process, thereby enhancing the grid-side operation support capability.

[0078] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0079] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of other embodiments of this disclosure upon considering the specification and practicing the disclosure herein. This invention is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A flywheel energy storage dual rotor dual stator permanent magnet brushless phase modulator system, characterized in that, This includes a dual-rotor, dual-stator permanent magnet brushless synchronous condenser, a flywheel, and a converter, among which... The dual-rotor, dual-stator permanent magnet brushless synchronous condenser includes an inner control stator, an inner modulation rotor, an outer permanent magnet rotor, and an outer power stator coaxially arranged from the inside out. Both the outer permanent magnet rotor and the inner modulation rotor can rotate freely relative to the outer power stator and the inner control stator. The external permanent magnet rotor is provided with a first number of permanent magnets to generate a first number of excitation magnetic fields. The internal modulation rotor is connected to the flywheel and forms an inertial body rotating at the same speed. Several sets of magnetic blocks are spaced apart on the internal modulation rotor to modulate the excitation magnetic field. The external power stator is provided with a power winding, and the power winding is configured with the first number of pole pairs; The inner control stator is provided with a control winding, which is configured as a second pole pair. The sum of the first number of pole pairs and the second number of pole pairs is equal to the number of magnetic blocks, and the first number of pole pairs and the second number of pole pairs are not equal; The modulation forms a first pole-log main magnetic field component corresponding to the power winding and a second pole-log modulated harmonic magnetic field component corresponding to the control winding. The power winding is connected to the grid side of the synchronous condenser system to serve as the main channel for active and reactive power interaction with the grid side. The control winding is connected to the grid side through the converter to adjust the rotational speed of the inertial body and the interactive active and reactive power.

2. A flywheel energy storage dual rotor dual stator permanent magnet brushless phase modifier system as claimed in claim 1, wherein, The internal modulation rotor includes several sets of fan-shaped magnetic blocks arranged circumferentially and non-magnetic blocks disposed between two adjacent magnetic blocks. The magnetic blocks and the non-magnetic blocks are connected end to end to form a ring, so as to form a periodic change in magnetic permeability in the circumferential direction of the internal modulation rotor.

3. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 1, characterized in that, The external power stator has a plurality of first salient pole teeth, and a first stator slot is formed between two adjacent first salient pole teeth, and the power winding is arranged in the first stator slot; The internal control stator has multiple second salient pole teeth, and a second stator slot is formed between two adjacent second salient pole teeth. The control winding is arranged in the second stator slot.

4. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 3, characterized in that, The power winding is formed by connecting multiple power coils, and the control winding is formed by connecting multiple control coils. Both the power coils and the control coils adopt a distributed winding structure.

5. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 1, characterized in that, The external permanent magnet rotor includes an annular magnetic yoke and permanent magnets respectively disposed on the outer and inner sides of the annular magnetic yoke. The permanent magnets located on the outer side of the annular magnetic yoke are used to couple with the air gap magnetic field corresponding to the power winding, and the permanent magnets located on the inner side of the annular magnetic yoke are used to couple with the air gap magnetic field corresponding to the control winding via the internal modulation rotor.

6. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 1, characterized in that, Permanent magnets are uniformly arranged circumferentially on both the outer and inner sides of the annular magnetic yoke. Each pair of permanent magnets includes two permanent magnets with opposite magnetization directions and radial magnetization, and the magnetization directions of adjacent permanent magnets are opposite.

7. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 1, characterized in that, The converter is a back-to-back converter.

8. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 7, characterized in that, The back-to-back converter consists of two three-phase full-bridge power circuits and one energy storage capacitor, with the energy storage capacitor arranged in the DC bus between the two three-phase full-bridge power circuits.

9. The flywheel energy storage dual-rotor dual-stator permanent magnet brushless phase shifter system as described in claim 1, characterized in that, The rated capacity of the converter is 20%-30% of the rated capacity of the synchronous condenser system.

10. A control method for a flywheel energy storage dual-rotor dual-stator permanent magnet brushless synchronous condenser system, characterized in that, include: Obtain the rate of change of the flywheel's rotational speed; When the speed change rate is greater than zero, the flywheel is determined to be in a speed-up energy storage state. The converter is controlled to adjust the current frequency input to the control winding in the positive direction so that the external permanent magnet rotor absorbs power from the grid side through the synchronous condenser system. When the rate of change of rotational speed is less than zero, it is determined that the flywheel is in a state of deceleration and energy release. The converter is controlled to adjust the current frequency input to the control winding in the negative direction so that the external permanent magnet rotor outputs power to the grid side through the synchronous condenser system.

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