Charging and discharging control method, central processing unit and system

Abstract

The invention discloses a charging and discharging control method, a central processing unit and a system. The method comprises the following steps: determining an operation mode of a flywheel motor based on a real-time rotating speed of the flywheel motor; based on the operation mode of the flywheel motor, determining a magnetic pole position and a rotating speed estimation value of a rotor by adopting a corresponding processing strategy; and controlling the motor to store or release electric energy by using the magnetic pole position and the rotating speed estimated value of the rotor in response to the flywheel system being in a motor mode or a generator mode. According to the flywheel energy storage system, a mechanical position sensor is omitted, the hardware cost of the flywheel energy storage system is greatly reduced, the size and weight of the flywheel system are reduced, the power density of the flywheel system is improved, and integrated installation of the flywheel system is more convenient.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a charging and discharging control method, a central processing unit, and a system. Background Technology

[0002] The flywheel energy storage system uses an integrated motor / generator to drive a flywheel to rotate at high speed, storing electrical energy as mechanical energy. When needed, the energy is released by the motor in reverse rotation. In the motor control stage of the flywheel energy storage system, the real-time and accurate acquisition of the rotor magnetic pole position is the core prerequisite for achieving vector control. Only by knowing the rotor position can the three-phase current be decoupled into excitation current and torque current through coordinate transformation, thereby achieving precise control of motor torque and speed.

[0003] In related technologies, mechanical position sensors, such as photoelectric encoders or rotary transformers, are required to determine the rotor position. However, mechanical sensors have significant limitations. For example, when the motor speed is less than 5% of the rated speed, the back electromotive force signal is weak and cannot be effectively detected, causing the flywheel to fail to start smoothly. Alternatively, the position estimation error may exceed a threshold, affecting control accuracy. Therefore, existing methods suffer from low technical reliability. Summary of the Invention

[0004] This disclosure provides a charging and discharging control method, a central processing unit, and a system to at least solve the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this application, a charge / discharge control method is provided, comprising: The operating mode of the flywheel motor is determined based on its real-time rotational speed. Based on the operating mode of the flywheel motor, the corresponding processing strategy is used to determine the rotor's magnetic pole position and speed estimate. In response to the flywheel system being in motor mode or generator mode, the motor is controlled to store or release electrical energy using the estimated values ​​of the rotor's magnetic pole position and rotational speed.

[0006] In one possible implementation, determining the operating mode of the flywheel motor based on the rotational speed includes: When the rotational speed is within a first threshold range, it is determined that the flywheel motor is in the start-up or low-speed phase; When the rotational speed is within the second threshold range, it is determined that the flywheel motor is in a stable operating phase; wherein, in the stable operating phase, the flywheel motor operates at a medium to high speed. When the rotational speed switches from a first threshold range to a second threshold range, it is determined that the flywheel motor is in a switching phase.

[0007] In one possible implementation, based on the operating mode of the flywheel motor, a corresponding processing strategy is used to determine the rotor's magnetic pole position and estimated rotational speed, including: In response to the flywheel motor being in the start-up or low-speed phase, a high-frequency voltage signal is injected into the stator winding of the flywheel motor to obtain a high-frequency response current; based on the high-frequency response current, a position tracking observer is used to determine the first position information and the first speed estimate of the rotor. When the flywheel motor is in a stable operating phase, the voltage and current of the motor are collected, and the extended back electromotive force (EMF) estimate of the motor is obtained using a sliding mode observer based on the voltage and current; the second position information and the second speed estimate of the rotor are determined based on the extended back EMF estimate. In response to the flywheel motor being in a switching phase, a weighted fusion algorithm is used to determine the third position information and the third speed estimate for the position tracking observer and the sliding mode observer.

[0008] In one possible implementation, in response to the flywheel system being in motor mode or generator mode, controlling the motor to store or release electrical energy using the estimated values ​​of the rotor's magnetic pole position and rotational speed includes: In response to the flywheel system being in motor mode, a speed closed loop is formed based on the rotor's magnetic pole position and speed estimate as feedback signals. By adjusting the motor's torque current, the motor drives the flywheel to accelerate in order to store kinetic energy. In response to the flywheel system being in generator mode, a preset DC bus voltage command is received. The DC bus voltage is used as the outer loop feedback signal, and the motor current is used as the inner loop feedback signal. Coordinate transformation and decoupling control are performed in conjunction with the magnetic pole position of the rotor to enable the motor to output a constant DC voltage.

[0009] In one possible implementation, after obtaining the high-frequency response current, the method further includes: Processing high-frequency response current; including: The high-frequency response current is filtered using a bandpass filter to remove interference signals, and then the filtered current signal is demodulated using a demodulator.

[0010] In one embodiment, the high-frequency voltage signal is a rotating high-frequency voltage vector or a pulsed high-frequency voltage vector with a frequency of 1-2 kHz.

[0011] In one possible implementation, after obtaining the extended back electromotive force estimate of the motor, the method further includes: The extended back EMF estimate obtained by the sliding mode observer is subjected to low-pass filtering.

[0012] According to a second aspect of this application, a central processing unit is provided, comprising: Memory, on which executable programs are stored; A processor for executing the executable program in the memory to implement the steps of the method according to any one of claims 1-7.

[0013] According to a third aspect of this application, a charging and discharging control system is provided, characterized in that it comprises: a central processing unit as described in claim 8; and A motor drive inverter, connected to a flywheel motor, is used to provide operating voltage and operating current to the flywheel motor according to control signals sent by the central processing unit; Voltage and current sampling circuits are used to collect the voltage and current of the motor in real time.

[0014] In one possible implementation, it further includes: The fault protection unit brakes and alarms when a fault occurs in the flywheel energy storage system.

[0015] According to a fourth aspect of this application, an electronic device is provided, comprising: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method described in this application.

[0016] According to a fifth aspect of this application, a non-transitory computer-readable storage medium is provided storing computer instructions for causing the computer to perform the methods described in this application.

[0017] According to a sixth aspect of this application, a computer program product is provided, comprising a computer program or instructions that, when executed by a processor, implement the method described in this application.

[0018] By utilizing the technical solution of this application, mechanical position sensors are completely eliminated, which not only significantly reduces the hardware cost of the flywheel energy storage system, but also reduces the system's size and weight, increases the system's power density, and makes the system easier to integrate and install.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0020] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0021] Figure 1 A schematic diagram illustrating the implementation flow of the charge / discharge control method in an embodiment of this application is shown; Figure 2 A schematic diagram of the controller structure in an embodiment of this application is shown. Figure 2 ; Figure 3 A block diagram illustrating the implementation of the charge / discharge control system in an embodiment of this application is shown. Detailed Implementation

[0022] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the following description, the terms "first" and "second" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first" and "second" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0025] The following description, in conjunction with the accompanying drawings, introduces a charging and discharging control method, a central processing unit, and a system provided in this application.

[0026] like Figure 1 As shown, this application provides a charging and discharging control method, including: S101, determine the operating mode of the flywheel motor based on the real-time speed of the flywheel motor; The operating modes of a flywheel motor include a start-up or low-speed phase, a stable operating phase, and a switching phase. The operating mode can be determined based on the motor's operating speed. For example, when the motor speed is below 5% of the rated speed, it is in the start-up or low-speed phase; when the motor speed rises to 5%-10% of the rated speed, it is in the stable operating phase. When the motor speed is 5% of the rated speed, it can be considered the switching phase.

[0027] In some embodiments, determining the operating mode of the flywheel motor based on the rotational speed includes: When the rotational speed is within a first threshold range, it is determined that the flywheel motor is in the start-up or low-speed phase; When the rotational speed is within the second threshold range, it is determined that the flywheel motor is in a stable operating phase; wherein, in the stable operating phase, the flywheel motor operates at a medium to high speed. When the rotational speed switches from a first threshold range to a second threshold range, it is determined that the flywheel motor is in a switching phase.

[0028] Specifically, in this application, the system enters this mode when the real-time rotational speed is lower than or equal to a preset first threshold (e.g., 5% of the rated speed). During this stage, the motor back EMF signal is weak and cannot be directly detected. The system enters this mode when the real-time rotational speed is higher than a preset second threshold (e.g., 10% of the rated speed). During this stage, the motor back EMF signal is strong enough for accurate observation. The system enters this mode when the real-time rotational speed rises from the first threshold range to the second threshold range. This stage aims to address the potential jumps in estimated values ​​and system disturbances that may occur when switching between the two main observation strategies.

[0029] S102, Based on the operating mode of the flywheel motor, the corresponding processing strategy is used to determine the magnetic pole position and speed estimate of the rotor; In this application, the most suitable sensorless position and speed estimation strategy is switched and applied according to the different operating stages of the flywheel motor to ensure high-precision and high-stability control can be achieved across the entire operating range.

[0030] In some embodiments, based on the operating mode of the flywheel motor, a corresponding processing strategy is used to determine the rotor's magnetic pole position and estimated rotational speed, including: In response to the flywheel motor being in the start-up or low-speed phase, a high-frequency voltage signal is injected into the stator winding of the flywheel motor to obtain a high-frequency response current; based on the high-frequency response current, a position tracking observer is used to determine the first position information and the first speed estimate of the rotor. When the flywheel motor is in a stable operating phase, the voltage and current of the motor are collected, and the extended back electromotive force (EMF) estimate of the motor is obtained using a sliding mode observer based on the voltage and current; the second position information and the second speed estimate of the rotor are determined based on the extended back EMF estimate. In response to the flywheel motor being in a switching phase, a weighted fusion algorithm is used to determine the third position information and the third speed estimate for the position tracking observer and the sliding mode observer.

[0031] It should be noted that this application determines the operating stage based on the real-time rotational speed of the flywheel motor and employs a corresponding sensorless observation algorithm to determine the rotor's magnetic pole position and estimated rotational speed. Specifically, in this application, during the start-up and low-speed phases, a high-frequency voltage signal is injected into the motor stator windings. By detecting the high-frequency response current and processing it through bandpass filtering, signal demodulation, and a position tracking observer, the first rotor position information (θ1) and the first estimated rotational speed (ω1) are calculated. During the medium-to-high-speed stable operation phase, the motor's terminal voltage and phase current are collected and input into a sliding mode observer designed based on current error to obtain the extended back-EMF estimate of the motor. After adaptive filtering of this estimate, the second rotor position information (θ2) and the second estimated rotational speed (ω2) are extracted using a phase-locked loop (PLL). During the switching phase, which is a transitional state, the high-frequency injection method and the sliding mode observer method are run in parallel. A weighted fusion algorithm is used to fuse the positions (θ1, θ2) and rotational speeds (ω1, ω2) estimated by the two methods respectively, and outputs a smooth third position information (θ3) and a third rotational speed estimate (ω3) to achieve a disturbance-free switching.

[0032] In some embodiments, after obtaining the high-frequency response current, the method further includes: Processing high-frequency response current; including: The high-frequency response current is filtered using a bandpass filter to remove interference signals, and then the filtered current signal is demodulated using a demodulator.

[0033] In this application, a bandpass filter with a center frequency matching the injected signal frequency is used to filter the original high-frequency response current. This step aims to filter out interference signals such as the fundamental operating current component and high-frequency switching noise, thereby purifying the effective high-frequency response component modulated by the rotor salient pole effect. Then, the filtered high-frequency current signal is sent to a demodulator (e.g., a synchronous detector). The demodulator uses a specific algorithm (such as multiplying with the injected high-frequency voltage signal and low-pass filtering) to strip away the carrier high-frequency component, thereby reconstructing the low-frequency envelope signal containing rotor position error information.

[0034] The high-frequency voltage signal is a rotating high-frequency voltage vector or a pulsed high-frequency voltage vector with a frequency of 1-2kHz.

[0035] S103, in response to the flywheel system being in motor mode or generator mode, uses the estimated values ​​of the rotor's magnetic pole position and rotational speed to control the motor to store or release electrical energy.

[0036] In some embodiments, the step of controlling the motor to store or release electrical energy in response to the flywheel system being in motor mode or generator mode, using the estimated values ​​of the rotor's magnetic pole position and rotational speed, includes: In response to the flywheel system being in motor mode, a speed closed loop is formed based on the rotor's magnetic pole position and speed estimate as feedback signals. By adjusting the motor's torque current, the motor drives the flywheel to accelerate in order to store kinetic energy. In response to the flywheel system being in generator mode, a preset DC bus voltage command is received. The DC bus voltage is used as the outer loop feedback signal, and the motor current is used as the inner loop feedback signal. Coordinate transformation and decoupling control are performed in conjunction with the magnetic pole position of the rotor to enable the motor to output a constant DC voltage.

[0037] Specifically, in this application, when the flywheel system is in motor mode, the system receives a preset speed command. The real-time speed estimated using the aforementioned method is used as feedback to form a speed closed-loop control. By adjusting the motor's torque current component, the motor is controlled to generate driving torque, driving the flywheel to accelerate and convert electrical energy into kinetic energy for storage. In generator mode, the system receives a preset DC bus voltage command. This voltage is used as the outer loop feedback signal, while the motor current is used as the inner loop feedback signal, forming a voltage-current dual closed-loop control. Coordinate transformation is performed using the rotor's real-time position angle estimated by the aforementioned method to achieve precise decoupling control of the torque current and excitation current, thereby ensuring a constant DC voltage output from the motor and stable power supply to the load.

[0038] In some embodiments, after obtaining the extended back electromotive force estimate of the motor, the method further includes: The extended back EMF estimate obtained by the sliding mode observer is subjected to low-pass filtering.

[0039] As a specific implementation method, the implementation process in this application is as follows: During startup and low-speed operation, a high-frequency signal injection method is used. When the motor is stationary or running at low speed, the rotor position is difficult to detect directly due to the weak back electromotive force signal. At this time, a non-fundamental frequency high-frequency voltage signal of 1-2 kHz is injected into the stator windings of the motor. This high-frequency voltage signal can be either a rotating high-frequency voltage vector or a pulsating high-frequency voltage vector. Due to the salient pole effect of the motor (equivalent salient pole caused by magnetic saturation in permanent magnet motors), the rotor position information is modulated into the high-frequency response current generated after the high-frequency voltage signal is injected. The high-frequency response current is filtered by a bandpass filter to remove interference signals, and then the filtered current signal is demodulated using a demodulator. Finally, the initial rotor position information is extracted by a position tracking observer, and the rotational speed at low speed is estimated, thereby achieving smooth startup and low-speed operation control of the flywheel motor.

[0040] During the stable operation phase at medium to high speeds, the sliding mode observer method is used. When the flywheel speed rises to 5%-10% of the rated speed, the motor back EMF reaches a sufficiently large value. At this point, the estimation method for rotor position and speed is switched to the model-based sliding mode observer method. A sliding mode observer is constructed, whose sliding surface function is designed based on current error. Its inputs are the motor terminal voltage and phase current collected by voltage and current sampling circuits, and its output is the estimated value of the extended back EMF of the motor. The sliding mode observer has strong robustness to parameter changes and external disturbances, making it very suitable for large inertia systems like flywheels. The extended back EMF estimate output by the sliding mode observer is subjected to low-pass filtering or adaptive filtering. The cutoff frequency of the low-pass filter is adaptively adjusted according to the estimated real-time speed to ensure a balance between filtering effect and signal response speed. Then, phase-locked loop technology is used to extract the smoothed real-time rotor position angle and real-time speed from the filtered extended back EMF estimate.

[0041] When the system operates in motor mode, the controller receives a preset speed command and uses the real-time speed estimated by the above method as a feedback signal to form a closed-loop speed control. By adjusting the motor's torque current, the controller controls the motor to generate corresponding torque, driving the flywheel to rotate faster, converting electrical energy into the flywheel's kinetic energy and storing it until the flywheel speed reaches the target speed.

[0042] When the system operates in generator mode, the controller receives a preset DC bus voltage command, uses the DC bus voltage as the outer loop feedback signal, and uses the motor current as the inner loop feedback signal. Combined with the estimated real-time rotor position angle, coordinate transformation is performed to achieve precise decoupling control of the current, thereby controlling the motor to output a constant DC voltage to supply power to the external load and complete the energy release process.

[0043] When switching between the high-frequency signal injection method during startup and low-speed phases and the sliding mode observer method during medium- and high-speed phases, a transition state is set. In this transition state, both the high-frequency signal injection method and the sliding mode observer method are run simultaneously. A weighted fusion algorithm is used to process the rotor position and speed estimated by the two methods, achieving a smooth transition and avoiding torque and speed fluctuations during mode switching. During charge and discharge control, a feedforward compensation algorithm is used, incorporating the estimated real-time speed as a feedforward quantity into the torque current setpoint to overcome the system inertia caused by the flywheel's rotational inertia and improve the system's dynamic response speed.

[0044] like Figure 2 As shown, this application embodiment provides a central processing unit, characterized in that it includes: Memory, on which executable programs are stored; A processor for executing the executable program in the memory to implement the method provided in any of the above embodiments.

[0045] like Figure 3 As shown, this application provides a charging and discharging control system, including the central processing unit as described in the above embodiments; and A motor drive inverter, connected to a flywheel motor, is used to provide operating voltage and operating current to the flywheel motor according to control signals sent by the central processing unit; Voltage and current sampling circuits are used to collect the voltage and current of the motor in real time.

[0046] In some embodiments, the technical solutions provided in this application further include: The fault protection unit brakes and alarms when a fault occurs in the flywheel energy storage system.

[0047] Specifically, in this application, the motor drive inverter is connected to the flywheel motor. Driven by the PWM control signal output by the central processing unit, it provides suitable voltage and current to the flywheel motor, realizing the motor's starting, acceleration, deceleration, and energy storage and release. The voltage and current sampling circuit collects the motor's terminal voltage and phase current in real time, converts the collected analog signals into digital signals, and transmits them to the central processing unit. The central processing unit can be a digital signal processor or an FPGA, configured to execute the aforementioned initial position and speed estimation steps, stable operation state observation steps, and charge / discharge control steps, and generate a PWM control signal based on the processing results to drive the motor drive inverter.

[0048] This application eliminates the need for mechanical position sensors, significantly reducing the hardware cost of the flywheel energy storage system, decreasing its size and weight, increasing its power density, and facilitating integration and installation. By combining high-frequency signal injection and sliding mode observer methods, and designing a smooth switching mechanism, sensorless precise control is achieved across the entire speed range, from zero-speed start-up and low-speed operation to high-speed stable operation, meeting the operational requirements of the flywheel energy storage system under various conditions. The employed sliding mode observer exhibits strong resistance to perturbations in motor parameters and external disturbances, ensuring stable control performance even under long-term operation and the influence of factors such as temperature changes. Simultaneously, the weighted fusion algorithm during mode switching avoids torque and speed fluctuations, further enhancing the system's operational stability.

[0049] This application may also include a communication unit for connecting to a host computer and a load-unloading circuit connected in parallel to the busbar. Each module is connected sequentially according to the signal flow direction via a shielded wire or a dedicated interface. When the system is running, after power-on, the central processing unit first completes hardware self-test and parameter loading. During the zero-speed to low-speed stage (speed ≤ 5% of rated speed), a high-frequency pulsating voltage is injected into the α-axis of the motor. After current acquisition, Clarke transformation, bandpass filtering and synchronous demodulation, the rotor position θ is estimated through a PI-PLL observer. h With rotational speed n h The drive motor starts smoothly; after the speed increases to 5% of the rated speed and stabilizes, it enters a transition phase where the results of the high-frequency injection method and the sliding mode observer method are weighted and fused. Then, it switches to the adaptive sliding mode observer, combining parameter adaptive compensation and variable cutoff frequency filtering, and outputs a high-precision position θ through a third-order phase-locked loop. m With rotational speed n m During charging, n m To create a speed closed loop for feedback, the motor drives the flywheel to accelerate and store energy. During discharge, the bus voltage forms the outer loop, and the current forms the inner loop, combined with θ. m It achieves rectification and voltage regulation, and ensures smooth operation by linearly adjusting the current supply during switching. In case of a fault, the protection module triggers an interrupt, and the central processing unit blocks PWM, start braking and alarm, completely eliminating the need for mechanical sensors while ensuring stable control across the entire speed range.

[0050] This application also provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the charging and discharging control method of this application.

[0051] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0052] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0053] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0054] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0055] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0056] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

[0057] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A charging and discharging control method, characterized in that, include: The operating mode of the flywheel motor is determined based on its real-time rotational speed. Based on the operating mode of the flywheel motor, the corresponding processing strategy is used to determine the rotor's magnetic pole position and speed estimate. In response to the flywheel system being in motor mode or generator mode, the motor is controlled to store or release electrical energy using the estimated values ​​of the rotor's magnetic pole position and rotational speed.

2. The method according to claim 1, characterized in that, Determining the operating mode of the flywheel motor based on the rotational speed includes: When the rotational speed is within a first threshold range, it is determined that the flywheel motor is in the start-up or low-speed phase; When the rotational speed is within a second threshold range, it is determined that the flywheel motor is in a stable operating phase; wherein, in the stable operating phase, the flywheel motor operates at a medium to high speed. When the rotational speed switches from a first threshold range to a second threshold range, it is determined that the flywheel motor is in a switching phase.

3. The method according to claim 2, characterized in that, Based on the operating mode of the flywheel motor, a corresponding processing strategy is used to determine the rotor's magnetic pole position and estimated rotational speed, including: In response to the flywheel motor being in the start-up or low-speed phase, a high-frequency voltage signal is injected into the stator winding of the flywheel motor to obtain a high-frequency response current; based on the high-frequency response current, a position tracking observer is used to determine the first position information and the first speed estimate of the rotor. When the flywheel motor is in a stable operating phase, the voltage and current of the motor are collected, and the extended back electromotive force (EMF) estimate of the motor is obtained using a sliding mode observer based on the voltage and current; the second position information and the second speed estimate of the rotor are determined based on the extended back EMF estimate. In response to the flywheel motor being in a switching phase, a weighted fusion algorithm is used to determine the third position information and the third speed estimate for the position tracking observer and the sliding mode observer.

4. The method according to claim 3, characterized in that, The response to the flywheel system being in motor mode or generator mode, using the estimated values ​​of the rotor's magnetic pole position and rotational speed, controls the motor to store or release electrical energy, including: In response to the flywheel system being in motor mode, a speed closed loop is formed based on the rotor's magnetic pole position and speed estimate as feedback signals. By adjusting the motor's torque current, the motor drives the flywheel to accelerate in order to store kinetic energy. In response to the flywheel system being in generator mode, a preset DC bus voltage command is received. The DC bus voltage is used as the outer loop feedback signal, and the motor current is used as the inner loop feedback signal. Coordinate transformation and decoupling control are performed in conjunction with the magnetic pole position of the rotor to enable the motor to output a constant DC voltage.

5. The method according to claim 3, characterized in that, After obtaining the high-frequency response current, it also includes: Processing high-frequency response current; including: The high-frequency response current is filtered using a bandpass filter to remove interference signals, and then the filtered current signal is demodulated using a demodulator.

6. The method according to claim 3, characterized in that, The high-frequency voltage signal is a rotating high-frequency voltage vector or a pulsed high-frequency voltage vector with a frequency of 1-2kHz.

7. The method according to claim 4, characterized in that, After obtaining the extended back electromotive force estimate of the motor, the following steps are also included: The extended back EMF estimate obtained by the sliding mode observer is subjected to low-pass filtering.

8. A central processing unit, characterized in that, include: Memory, on which executable programs are stored; A processor for executing the executable program in the memory to implement the steps of the method according to any one of claims 1-7.

9. A charging and discharging control system, characterized in that, include: The central processing unit as described in claim 8; as well as A motor drive inverter, connected to a flywheel motor, is used to provide operating voltage and operating current to the flywheel motor according to control signals sent by the central processing unit; Voltage and current sampling circuits are used to collect the voltage and current of the motor in real time.

10. The charging and discharging control system according to claim 9, characterized in that, Also includes: The fault protection unit brakes and alarms when a fault occurs in the flywheel energy storage system.

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