Hybrid energy storage device and control system thereof

Abstract

The invention discloses a hybrid energy storage device and a control system thereof, and relates to the technical field of electric vehicle energy management, the device comprises a power battery, a first flywheel, a second flywheel, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a driving motor circuit; one end of the power battery is connected with the second flywheel, the third switch, the fourth switch and one end of the driving motor circuit; the other end of the power battery is connected with one end of the first switch; the other end of the first switch is respectively connected with one end of the second switch and the other end of the driving motor circuit; the other end of the second switch is connected with the other end of the third switch, one end of the first flywheel and one end of the sixth switch. The other end of the first flywheel is connected with the other end of the fourth switch and one end of the fifth switch. And the other end of the sixth switch is connected with the other end of the second flywheel and the other end of the fifth switch. According to the application, different requirements of the power motor on braking power can be responded.

Description

Technical Field

[0001] This application relates to the field of electric vehicle energy management technology, and in particular to a hybrid energy storage device and its control system. Background Technology

[0002] As a core component of regenerative braking systems, energy storage systems play a crucial role in the energy management and optimization of electric vehicles.

[0003] Currently, a single power battery is mainly used as the energy storage system for pure electric vehicles. This approach has certain limitations: First, the power battery is prone to capacity decay during frequent charging and discharging, leading to a reduction in its lifespan; second, the power density of the power battery is relatively low, and the large current demand generated during rapid acceleration or emergency braking of the vehicle will have a significant impact on the battery. Summary of the Invention

[0004] The purpose of this application is to provide a hybrid energy storage device and its control system, which provides multiple energy storage states to respond to different braking power requirements of the power motor.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] In a first aspect, this application provides a hybrid energy storage device, comprising: a power battery, a first flywheel, a second flywheel, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a drive motor circuit.

[0007] One end of the power battery is connected to one end of the second flywheel, one end of the third switch, one end of the fourth switch, and one end of the drive motor circuit.

[0008] The other end of the power battery is connected to one end of the first switch.

[0009] The other end of the first switch is connected to one end of the second switch and the other end of the drive motor circuit.

[0010] The other end of the second switch is connected to the other end of the third switch, one end of the first flywheel, and one end of the sixth switch.

[0011] The other end of the first flywheel is connected to the other end of the fourth switch and one end of the fifth switch, respectively.

[0012] The other end of the sixth switch is connected to the other end of the second flywheel and the other end of the fifth switch, respectively.

[0013] Secondly, this application provides a hybrid energy storage control system, comprising: the hybrid energy storage device described in any one of the above, and a controller; the controller is used to control the switching states of the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch to respond to multiple operating modes of the hybrid energy storage device.

[0014] According to the specific embodiments provided in this application, this application has the following technical effects:

[0015] This application provides a hybrid energy storage device and its control system. The device comprises a power battery, a first flywheel, a second flywheel, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. One end of the power battery is electrically connected to one end of the second flywheel, one end of the third switch, and one end of the fourth switch. The other end of the power battery is connected to one end of the first switch. The other end of the first switch is connected to one end of the second switch. The other end of the second switch is connected to the other end of the third switch, one end of the first flywheel, and one end of the sixth switch. The other end of the first flywheel is connected to the other ends of the fourth switch and the fifth switch. The other end of the sixth switch is connected to the other ends of the second flywheel and the fifth switch. The first flywheel, second flywheel, and power battery form a hybrid energy storage structure. When the first switch cuts off the power battery from receiving braking energy, the first and second flywheels undertake high-power tasks such as braking energy recovery and acceleration, which can meet the high power requirements of the drive motor and reduce the number of charge-discharge cycles of the power battery. When the second switch cuts off the first and second flywheels from receiving braking energy, the power battery alone can provide a stable energy supply. When the drive motor, first flywheel, and second flywheel simultaneously receive braking energy, the drive motor's ultra-high power requirements can be met. Therefore, the hybrid energy storage device can provide multiple energy storage states, respond to the different braking power requirements of the power motor, and reduce the impact on the power battery during vehicle operation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a hybrid energy storage device according to one embodiment of this application;

[0018] Figure 2a This is a schematic diagram of a Type I semi-active hybrid energy storage structure.

[0019] Figure 2bThis is a schematic diagram of a Type II semi-active hybrid energy storage structure.

[0020] Figure 3a A hybrid energy storage control system according to one embodiment of this application Figure 1 The diagram shows the energy flow direction in the start-up mode when the hybrid energy storage device is controlled.

[0021] Figure 3b A hybrid energy storage control system according to one embodiment of this application Figure 1 The diagram shows the energy flow direction in constant speed driving mode when the hybrid energy storage device is controlled.

[0022] Figure 3c A hybrid energy storage control system according to one embodiment of this application Figure 1 The diagram shows the energy flow direction in acceleration or ramping mode when the hybrid energy storage device is controlled.

[0023] Figure 3d-1 A hybrid energy storage control system according to one embodiment of this application Figure 1 The diagram shows the direction of energy flow in series with the flywheel during braking mode when the hybrid energy storage device is under control.

[0024] Figure 3d-2 A hybrid energy storage control system according to one embodiment of this application Figure 1 The diagram shows the direction of energy flow in the flywheel parallel connection during braking mode when the hybrid energy storage device is controlled.

[0025] Figure 4 This is a schematic diagram of a hybrid energy storage control system structure according to one embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the structure of an active disturbance rejection controller in a hybrid energy storage control system according to an embodiment of this application;

[0027] Figure 6 The graph shows the variation of the processing function in the existing active disturbance rejection controller under different parameters.

[0028] Figure 7 A comparison diagram of the processing function characteristics in an active disturbance rejection controller in an embodiment of this application;

[0029] Figure 8 To and Figure 7 A comparison chart of the error gain values ​​of the two corresponding processing functions;

[0030] Figures 9-14 This is a comparison diagram of the control effect of the active disturbance rejection controller in one embodiment of this application and the prior art.

[0031] Reference numerals: 1 Hybrid energy storage device, 2 Controller. Detailed Implementation

[0032] The technical solutions of 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.

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] In existing technologies, hybrid energy storage systems consisting of flywheels and power batteries are classified into passive, active, and semi-active structures. The semi-active structure introduces only one DC / DC converter to actively control one energy storage device in the hybrid system, while the other energy storage device is passively connected. This effectively improves control efficiency and reduces control complexity. Compared to passive structures, semi-active structures effectively reduce the impact of circulating currents and can achieve active energy distribution; compared to active structures, semi-active structures have lower control difficulty and cost.

[0035] However, due to the connection method of the semi-active structure, it still has some problems with incomplete energy management and lacks power conversion devices, which makes it impossible to make more precise adjustments to energy flow, resulting in energy loss.

[0036] like Figure 2a and Figure 2b The diagram shows the structures of two semi-active hybrid energy storage devices. Figure 2a The diagram shows a Type I structure, which uses active control of the flywheel (FESS) power output to enable it to respond quickly to high-frequency fluctuations, while the power battery only handles low-frequency energy demands. However, battery voltage fluctuations may affect system stability.

[0037] Figure 2b The diagram shows a Type II structure, where the battery is actively connected to the DC / DC converter, and the flywheel (FESS) is passively connected in parallel to the DC bus. The battery voltage is adjusted to match the flywheel (FESS), optimizing battery life and energy distribution. However, the FESS power response is limited by the bus voltage.

[0038] In summary, the Type I structure focuses on optimizing battery life, while the Type II structure focuses on high-frequency power response capability. The configuration should be selected according to the application scenario requirements. The hybrid energy storage device in this application is designed based on the Type I structure as the topology of the hybrid energy storage system.

[0039] In one exemplary embodiment, such as Figure 1As shown, a hybrid energy storage device is provided, including: a power battery, a first flywheel FESS1, a second flywheel FESS2, a first switch K1, a second switch V1, a third switch V2, a fourth switch VT1, a fifth switch VT2, a sixth switch VT3, and a drive motor circuit.

[0040] One end of the power battery is connected to one end of the second flywheel FESS2, one end of the third switch V2, one end of the fourth switch VT1, and one end of the drive motor circuit.

[0041] The other end of the power battery is connected to one end of the first switch K1.

[0042] The other end of the first switch K1 is connected to one end of the second switch V1 and the other end of the drive motor circuit.

[0043] The other end of the second switch V1 is connected to the other end of the third switch V2, one end of the first flywheel FESS1, and one end of the sixth switch VT3.

[0044] The other end of the first flywheel FESS1 is connected to the other end of the fourth switch VT1 and one end of the fifth switch VT2.

[0045] The other end of the sixth switch VT3 is connected to the other end of the second flywheel FESS2 and the other end of the fifth switch VT2, respectively.

[0046] In one exemplary embodiment, the hybrid energy storage device further includes a bidirectional DC / DC converter, a three-phase inverter, and a power module, wherein the power module is used to supply power to the hybrid energy storage device, and the three-phase inverter and the bidirectional DC / DC converter are connected in parallel with the drive motor circuit.

[0047] In another exemplary embodiment, a three-phase inverter (not shown in the figure) is used in... Figure 1 The circuit shown connects the drive motor and capacitor C3 in parallel; a bidirectional DC / DC converter (not shown) is placed between them. Figure 1 In the circuit shown, capacitor C1 is connected in parallel with capacitor C1 between the branch formed by the second flywheel and the sixth switch VT3.

[0048] In another exemplary embodiment, a bidirectional DC / DC converter (not shown) is provided. Figure 1 The circuit shown connects capacitor C2 to the branch containing the power battery, and is connected in parallel with capacitor C2.

[0049] In another exemplary embodiment, a bidirectional DC / DC converter (not shown) is provided. Figure 1The circuit shown has capacitors C1 and C2 connected in parallel.

[0050] This embodiment constructs a hybrid energy storage structure with the first flywheel FESS1, the second flywheel FESS2, and the power battery. When the first switch K1 cuts off the power battery from receiving braking energy, the first flywheel FESS1 and the second flywheel FESS2 undertake high-power tasks such as braking energy recovery and acceleration, which can meet the high power requirements of the drive motor and reduce the number of charge and discharge cycles of the power battery. When the second switch V1 cuts off the first flywheel FESS1 and the second flywheel FESS2 from receiving braking energy, the power battery can output a stable energy supply. When the drive motor, the first flywheel FESS1, and the second flywheel FESS2 simultaneously receive braking energy, the drive motor's ultra-high power requirements can be met. Therefore, the hybrid energy storage device can provide multiple energy storage states to respond to the different braking power requirements of the power motor and reduce the impact on the power battery during vehicle operation.

[0051] In one exemplary embodiment, such as Figure 1 As shown, the first switch K1, the second switch V1, the third switch V2, the fourth switch VT1, the fifth switch VT2, and the sixth switch VT3 are all insulated gate bipolar transistors.

[0052] By utilizing insulated gate bipolar transistors, series-parallel switching control is performed on the two flywheels (first flywheel FESS1 and second flywheel FESS2) in the hybrid energy storage device to achieve multiple voltage level outputs and regenerative braking, thereby achieving synergistic optimization of power density and energy density.

[0053] In one exemplary embodiment, such as Figure 1 As shown, multiple capacitors are connected in parallel across the two ends of the drive motor circuit, and an inductor is connected in series between the other end of the second switch V1 and one end of the first flywheel FESS1.

[0054] Under different operating conditions, the components (such as capacitors and inductors) in the hybrid energy storage device work in conjunction with the switches (first switch K1, second switch V1, third switch V2, fourth switch VT1, fifth switch VT2 and sixth switch VT3) to adjust the current and power, thereby achieving organic coordination between the energy storage devices and ensuring stable system operation.

[0055] In one exemplary embodiment, such as Figure 4As shown, a hybrid energy storage control system is provided, the hybrid energy storage control system including the hybrid energy storage device described in any of the preceding claims, and a controller; the controller is used to control the switching states of the first switch K1, the second switch V1, the third switch V2, the fourth switch VT1, the fifth switch VT2 and the sixth switch VT3, in response to multiple operating modes of the hybrid energy storage device.

[0056] In one exemplary embodiment, the operating modes include a start mode, a constant speed driving mode, an acceleration or hill-climbing mode, and a braking mode.

[0057] The controller is used for:

[0058] In the startup mode, the first switch K1, the second switch V1 and the fifth switch VT2 are turned on, the third switch V2, the fourth switch VT1 and the sixth switch VT3 are turned off, and the PWM signal of the second switch V1 is adjusted to adjust the output voltage of the first flywheel FESS1 and the second flywheel FESS2.

[0059] In the constant speed driving mode, the first switch K1 is turned on, and the second switch V1, the fifth switch VT2, the third switch V2, the fourth switch VT1, and the sixth switch VT3 are turned off.

[0060] In the acceleration or hill-climbing mode, the first switch K1, the second switch V1 and the fifth switch VT2 are turned on, the third switch V2, the fourth switch VT1 and the sixth switch VT3 are turned off, and the PWM signal of the second switch V1 is adjusted to regulate the current.

[0061] In the braking mode, the first switch K1 is controlled to be open, the second switch V1 is controlled to be open, the PWM signal of the second switch V1 is adjusted to adjust the output voltage of the first flywheel FESS1 and the second flywheel FESS2, and the switching states of the fifth switch VT2, the third switch V2, the fourth switch VT1 and the sixth switch VT3 are controlled according to the back induced electromotive force generated by the drive motor circuit, the voltage of the first flywheel FESS1 and the voltage of the second flywheel FESS2.

[0062] In an exemplary embodiment, similar to the previous embodiment, wherein, in controlling the switching states of the fifth switch VT2, the third switch V2, the fourth switch VT1, and the sixth switch VT3 based on the back-induced electromotive force generated by the drive motor circuit, the voltage of the first flywheel FESS1, and the voltage of the second flywheel FESS2, the controller is configured to:

[0063] Obtain the back induced electromotive force generated by the drive motor circuit.

[0064] When the reverse induced electromotive force is greater than the sum of the voltage of the first flywheel FESS1 and the voltage of the second flywheel FESS2, the fifth switch VT2 is turned on, and the fourth switch VT1, the third switch V2 and the sixth switch VT3 are turned off, so that the first flywheel FESS1 and the second flywheel FESS2 are connected in series.

[0065] When the reverse induced electromotive force is less than or equal to the sum of the voltage of the first flywheel FESS1 and the voltage of the second flywheel FESS2, the fifth switch VT2 and the third switch V2 are controlled to open, and the fourth switch VT1 and the sixth switch VT3 are controlled to open, so that the first flywheel FESS1 and the second flywheel FESS2 are connected in parallel.

[0066] The working principle of the controller is as follows:

[0067] During driving, a car encounters various complex operating conditions, each with different requirements for the energy storage system. For example, in congested urban areas where vehicles frequently start and stop, the energy storage system needs to respond quickly, frequently absorbing and releasing energy; while during constant-speed driving, the energy storage system needs to be able to continuously and stably output energy. Therefore, operating conditions are rationally divided into four types.

[0068] (1) Start-up mode: When the vehicle starts, the drive motor needs to output a large torque quickly, which requires the energy storage system to provide high power energy. This will have a large impact on the power battery pack, causing the battery life to decrease. Therefore, in this mode, when the energy storage is sufficient, the first flywheel FESS1 and the second flywheel FESS2 undertake the high power task, and the power battery stops working. Only when the energy storage of the first flywheel FESS1 and the second flywheel FESS2 is insufficient or there is no energy storage, will the power battery pack participate in the start-up work.

[0069] A schematic diagram of the energy flow direction in the startup mode is shown below. Figure 3a As shown, at this time, the fifth switch VT2 is turned on, making the first flywheel FESS1 and the second flywheel FESS2 in series; the fourth switch VT1 is turned off, preventing energy backflow from the hybrid energy storage device; the first switch K1 is turned off, cutting off the energy output path of the power battery to avoid affecting the normal operation of the hybrid energy storage device; the third switch V2 is turned off, preventing energy diversion; and the sixth switch VT3 is turned off, preventing malfunction of the hybrid energy storage device caused by incorrect conduction. This allows for the output of higher power to meet the high power demands during vehicle startup. The output voltage of the first flywheel FESS1 and the second flywheel FESS2 can be adjusted by regulating the PWM signal of the second switch V1.

[0070] (2) Constant speed driving mode: When the vehicle is driving at a constant speed, the vehicle brakes less frequently and requires a long-term and stable energy supply. Therefore, the first flywheel FESS1 and the second flywheel FESS2 do not participate in the work, and the power battery alone undertakes the task of stable energy output.

[0071] A schematic diagram of the energy flow direction in constant speed driving mode is shown below. Figure 3b As shown, at this time, the first switch K1 is in the conducting state, powered solely by the power battery to ensure the vehicle maintains a constant speed; the third switch V2 is off to prevent energy backflow; the second switch V1 is off, cutting off other energy branches. The first flywheel FESS1 and the second flywheel FESS2 do not participate in operation, ensuring that the energy supply of the hybrid energy storage device comes solely from the power battery.

[0072] (3) Acceleration or Climbing Mode: When the vehicle accelerates or climbs a hill, it has a high demand for the output torque of the drive motor. Therefore, the hybrid energy storage device needs to supply very high power to the drive motor. Although the first flywheel FESS1 and the second flywheel FESS2 can quickly respond to high power demands, in this situation, using only the first flywheel FESS1 and the second flywheel FESS2 is insufficient to meet the extremely high power requirements of the drive motor. Therefore, the power battery needs to participate in the work, and the two energy storage devices need to work together to ensure that the vehicle can smoothly complete the acceleration or climbing action.

[0073] A schematic diagram of the energy flow direction in acceleration or ramping mode is shown below. Figure 3c As shown, at this time, the first switch K1 is turned on to ensure that the stable energy output of the power battery pack can flow smoothly into the drive motor; the fifth switch VT2 is turned on, so that the first flywheel FESS1 and the second flywheel FESS2 can respond quickly and output energy, and work together with the power battery; the third switch V2 is turned off to avoid energy diversion; the second switch V1 is controlled by the PWM signal to precisely adjust the current and ensure the efficient and safe operation of the car.

[0074] (4) Braking Mode: When the vehicle brakes, the first switch K1 is open, cutting off the power battery from receiving braking energy; the second switch V1 is open, and the first flywheel FESS1 and the second flywheel FESS2 absorb the energy generated by regenerative braking, reducing the large current impact on the power battery. At this time, the magnitude of the back induced electromotive force generated by the drive motor changes according to factors such as vehicle speed and braking intensity. Based on the magnitude of the back induced electromotive force of the drive motor and the voltage of the first flywheel FESS1 and the second flywheel FESS2, the first flywheel FESS1 and the second flywheel FESS2 are connected in series or in parallel.

[0075] Series Connection: When the back-induced electromotive force of the drive motor is greater than the sum of the voltages of the first flywheel FESS1 and the second flywheel FESS2, the second switch V1 and the fifth switch VT2 are turned on, allowing the energy generated by the drive motor to flow to the first flywheel FESS1 and the second flywheel FESS2; the fourth switch VT1 and the sixth switch VT3 are turned off to prevent energy diversion; the first switch K1 is turned off to prevent the power battery from participating in regenerative braking. At this time, the first flywheel FESS1 and the second flywheel FESS2 are connected in series, and their voltages can be superimposed, thus better adapting to and absorbing the energy generated by the higher back-induced electromotive force of the motor. The magnitude of the regenerative voltage can be adjusted by regulating the PWM signal of the second switch V1. A schematic diagram of the energy flow direction of the flywheels in series under braking mode is shown below. Figure 3d-1 As shown.

[0076] Parallel Connection: When the back-induced electromotive force of the drive motor is less than the sum of the voltages of the first flywheel FESS1 and the second flywheel FESS2, the fourth switch VT1 and the sixth switch VT3 are turned on, allowing the current generated by the drive motor to flow precisely to the first flywheel FESS1 and the second flywheel FESS2; the fifth switch VT2 is turned off to avoid forming other unnecessary loops. In parallel connection, the back-induced electromotive force of the motor is relatively small. Using a series connection would cause the voltages of the first flywheel FESS1 and the second flywheel FESS2 to rise overall, preventing them from effectively absorbing the energy generated by the drive motor. However, in parallel mode, the first flywheel FESS1 and the second flywheel FESS2 can each receive the energy generated by the drive motor according to their own voltages, effectively improving energy recovery efficiency. A schematic diagram of the energy flow direction in parallel flywheel connection during braking mode is shown below. Figure 3d-2 As shown.

[0077] Therefore, this embodiment can effectively improve the efficiency of braking energy recovery and can more flexibly adapt to various braking situations.

[0078] In the above embodiments, the first flywheel FESS1 and the second flywheel FESS2 (collectively referred to as flywheels) are mainly composed of flywheel rotors, electric motors / generators, bearing systems, vacuum chambers, power electronic devices and other parts (casing, support system, cooling system, shaft positioning system and shaft displacement testing device, etc.).

[0079] The working principle of the flywheel is as follows: during the charging stage, external AC power is converted into DC power by the power electronic device. The motor receives the electrical energy and runs as a motor, converting electrical energy into mechanical energy to drive the rotor to rotate at high speed. During the discharging stage, the high-speed rotating rotor drives the motor to run as a generator, converting the rotational mechanical energy into electrical energy for output. The power electronic device rectifies and inverts the generated AC power to output DC power that meets the requirements.

[0080] Other components of the flywheel also play crucial roles: the bearing system is paramount, significantly reducing frictional losses and improving system efficiency. The vacuum chamber provides the rotor with a near-air-resistance-free environment, further minimizing energy loss and enabling the rotor to rotate at high speeds for extended periods, maintaining its energy storage state. Throughout the charging and discharging process, the cooling system constantly monitors and regulates the temperature to prevent the motor from overheating due to resistance, which could negatively impact performance. The support system provides structural support for the flywheel, ensuring the correct positioning of all components. The outer casing provides protection and isolation. The shaft system efficiently transmits mechanical energy, ensuring smooth energy transfer between the rotor and the motor / generator.

[0081] In a flywheel, the rotor is the core component of the system, undertaking the critical task of storing and releasing energy, and is manufactured using high-strength materials, such as carbon fiber composites.

[0082] The electric motor / generator is another key component of the flywheel, responsible for energy conversion. In this process, the efficiency, power density, speed regulation performance, and reliability of the electric motor / generator directly impact the performance of the entire flywheel energy storage system.

[0083] Compared to other motors, permanent magnet synchronous motors (PMSMs) are ideally suited for use as flywheel drive motors due to their superior performance characteristics. PMSMs not only offer high power density and efficiency, meeting the flywheel's requirements for compact structure and high speed, but also reduce losses during energy conversion, making them suitable for applications with frequent charge and discharge cycles. Because PMSMs have the highest speed, they allow for larger energy storage capacity in flywheels when used as drive motors. Furthermore, PMSMs can be directly integrated with flywheels, simplifying system design and further improving frequency regulation response speed and accuracy through their efficient energy conversion. In addition, PMSMs also offer advantages such as high torque density and rapid dynamic response.

[0084] In an exemplary embodiment, the motors in the first flywheel FESS1 and the second flywheel FESS2 in the hybrid energy storage control system are permanent magnet synchronous motors.

[0085] The energy stored in a flywheel is directly proportional to its moment of inertia and the square of its rotational speed. Increasing the flywheel's moment of inertia can effectively expand its energy storage capacity to some extent. However, when the moment of inertia is too high, the system's starting and braking characteristics will deteriorate significantly, specifically manifested as prolonged start-up time and increased energy consumption. It will also cause sluggish dynamic response, significantly increase control complexity, substantially limit system bandwidth, and excite system resonance. Increasing the rotational speed can also enhance the system's energy storage capacity, but increasing the rotational speed places more stringent demands on the control precision of the speed closed-loop control system. Therefore, in practical engineering applications, more advanced and precise speed control strategies and techniques are needed to ensure that the system can maintain stable and efficient operating performance under conditions of high moment of inertia and high rotational speed.

[0086] In recent years, Active Disturbance Rejection Control (ADRC) has been widely used in the speed control of permanent magnet synchronous motors. Its working principle is based on an extended state observer, which estimates the internal dynamic changes and external disturbances of the system in real time and with high accuracy, covering various complex factors such as load fluctuations and parameter perturbations during motor operation. The estimated values ​​are used as feedback compensation signals and input into the control system to achieve rapid suppression of various disturbances, thereby achieving high-precision control of the motor speed. Its core technology lies in the nonlinear state error feedback law, which treats the total system disturbance as a whole for unified compensation, avoiding the complex process of modeling and processing different disturbance sources separately. In traditional ADRC, the first-order system consists of the following three parts:

[0087] (1) Nonlinear Differential Tracker (TD):

[0088] TD is primarily used for signal processing and trajectory planning, quickly and smoothly tracking input signals and performing differentiation processing on them. Its core functions include: smoothing the transition of input signals to avoid abrupt changes and overshoot; suppressing input signal noise to output a smooth and well-tracking signal; and using f... al The function achieves the control effect of "small error, large gain; large error, small gain", f al The function can be represented by the following formula:

[0089]

[0090] e0 is the error signal of TD, v * This is the TD input signal, v1 is the speed tracking signal, r0 is the speed factor, and f al It is a nonlinear optimal control function, where a0 is the tracking factor and δ0 is the filter factor correction.

[0091] (2) Expanded State Observer (ESO):

[0092] ESO is a tool for real-time estimation of system state and disturbances, effectively handling uncertainties and external disturbances in systems. ESO first initializes and sets parameters, estimates internal state and external disturbances, continuously collects input and output data, calculates errors, and corrects the estimates through a feedback mechanism. Then, it utilizes a nonlinear function f... al The function dynamically updates the estimated value, gradually approximating the actual situation. Finally, the ESO generates a compensation signal based on the accurate disturbance estimate, feeding it back into the system to cancel the disturbance and ensure stable system operation. ESO has low model dependency; robust control can be achieved with coarse modeling, making it suitable for complex nonlinear systems, especially in strongly nonlinear scenarios with frequent disturbances. It can be expressed as follows:

[0093]

[0094] e1 is the error signal of the ESO, z1 is the tracking signal of the controlled object's output signal, y is the output signal of the controlled object, z2 is the disturbance observation value, β1 and β2 are the output errors of the ESO, and f al It is a nonlinear optimal control function, where a1 is the tracking factor, δ1 is the filter factor correction, b0 is the compensation factor, and u(t) is the control variable.

[0095] (3) Nonlinear State Error Feedback Control Low (NLSEF):

[0096] NLSEF is an error-based nonlinear control method used to replace traditional linear PID controllers. It first receives the system state estimate and total disturbance estimate from the ESO, and the desired trajectory and its derivative generated by the TD. Then, it utilizes f... al The function processes the error signal to form a nonlinear combination control law. This law dynamically adjusts the gain based on the error magnitude, achieving a "large gain for small errors, small gain for large errors" effect, thus improving the system's anti-interference capability and dynamic response performance. Finally, the output control signal is used to compensate for system disturbances, enabling the system to quickly and stably track the desired trajectory. This effectively suppresses tracking errors and external disturbances, and can be expressed by the following formula:

[0097]

[0098] e2 is the NLSEF error signal, z1 is the tracking signal of the controlled object's output signal, v1 is the speed tracking signal, u and u0(t) are control variables, k is the regulator gain, and f al is the nonlinear optimal control function, z2 is the disturbance observation, a2 is the tracking factor, δ2 is the filter factor correction, and b0 is the compensation factor.

[0099] All three components of the traditional ADRC involve f al The function, whose design philosophy is to optimize the system's control performance through nonlinear gain adjustment: for large errors, f al The function provides a small gain to quickly reduce errors and avoid excessive system response; while for smaller errors, it provides a larger gain to fine-tune the system to a steady state, improving convergence speed and control accuracy. al The function can be represented by the following formula:

[0100]

[0101] In the formula, e is f al The input error signal of the function; 'a' is a nonlinear factor used to control the curvature of the function; 'δ' is the threshold of the linear interval, determining the switching point; 'sgn' is the sign function. When the error signal is in the large error interval (|e|>δ), f al The function employs non-linear processing, slowing down the output growth to avoid overshoot; when in the small error range (|e|≤δ), it switches to linear amplification to improve convergence speed and enhance sensitivity.

[0102] Although f al The function value is continuous at |e|=δ (both sides are δ^α), but its derivative is discontinuous at the switching point, which may lead to high-frequency components in the control signal. The choice of δ needs to precisely match the system characteristics. If δ is too small, the gain in the linear region will be too high, which may cause oscillations; if δ is too large, it will enter the nonlinear region too early, which will reduce the response speed. δ is set to 0.2, and α is set to 0.25, 0.5, 0.75, and 1 respectively. al The curve of the function is as follows Figure 6 As shown.

[0103] from Figure 6 It can be seen that when the system needs to accelerate error convergence, it is necessary to increase the error gain within a lower error range to improve performance. However, increasing the error gain is accompanied by a significant increase in the slope of the linear function, i.e., an increase in the switching interval gain, which leads to strong oscillations. Therefore, it is necessary to design an improved f... al The optimal control function is selected based on the following principles: odd function, smooth and continuous, near linear at far points, and saturation characteristics. Its core idea is to replace large errors with small gains and small errors with large gains.

[0104] In existing technologies, the control system of a permanent magnet synchronous motor consists of a speed loop control and a current loop control working together. The speed loop control, as the outer loop of the control system, is responsible for regulating the motor speed. It obtains the actual motor speed feedback signal, compares it with the target speed, and uses classic control strategies such as PI control to dynamically adjust the output control signal based on the speed deviation between the two. This signal is then transmitted to the current loop control to achieve precise control of the motor speed, thereby meeting the stringent requirements for motor speed under different operating conditions. The current loop control, as the inner loop of the control system, is used to precisely control the motor current. The current loop control monitors the motor winding current in real time, compares the collected current feedback value with the current setpoint output by the speed loop, and uses control algorithms, such as Space Vector Pulse Width Modulation (SVPWM) technology, to adjust the voltage vector output by the inverter, thereby controlling the magnitude and phase of the motor current. The first-order system formula for the speed loop is as follows:

[0105]

[0106] Where, ω r It is the rotor electrical angular velocity of the permanent magnet synchronous motor; I q It is the q-axis current, i q This is the final output q-axis current reference control signal; b is an intermediate parameter, b = 1.5n. p Ψ f / J; f represents the total disturbance, J is the moment of inertia, and n p It is the extreme logarithm, T L It is the load torque, B is the viscous friction coefficient, Ψ f It is a permanent magnet flux linkage. According to formula (4), changes in load torque will directly affect the motor speed and dynamic response.

[0107] Therefore, a first-order active disturbance rejection controller (ADC) specifically designed for permanent magnet synchronous motor (PMSM) speed control loop was developed to effectively suppress interference factors such as load torque. Considering the aforementioned characteristics of the sine function, the following preferred embodiment is proposed:

[0108] In an exemplary embodiment, the method is the same as the previous embodiment, except that it further includes an active disturbance rejection controller, which is used to acquire a target speed signal and the actual speed signal of the permanent magnet synchronous motor, and to obtain the output current of the permanent magnet synchronous motor based on the target speed signal and the actual speed signal.

[0109] In one exemplary embodiment, the method is the same as the previous embodiment, except that, as Figure 5As shown, the active disturbance rejection controller includes a nonlinear differential tracker TD, an extended state observer ESO, and a linear feedback control law NLSEF.

[0110] The nonlinear differential tracker TD is used to analyze the acquired target velocity signal ω. gi The velocity tracking signal ω is obtained by tracking. tr and the velocity tracking signal ω tr Feedback is provided to the linear feedback control law NLSEF.

[0111] The extended state observer is used to obtain a feedback speed signal based on the acquired actual speed signal and the control current of the permanent magnet synchronous motor, and then feeds the feedback speed signal back to the linear feedback control law.

[0112] The linear feedback control law is used to acquire the feedback speed signal and the speed tracking signal, and to obtain and output the control current based on the feedback speed signal and the speed tracking signal. Then, the control current is fed back to the extended state observer; the control current is the output current of the permanent magnet synchronous motor.

[0113] In one exemplary embodiment, the nonlinear differential tracker is used to process the error between the acquired target velocity signal and the output velocity tracking signal based on a first function.

[0114] The expression for the first function is:

[0115]

[0116] Among them, if al Let λ represent the first function, where λ is the amplitude of the sine function and λ>0; M is the velocity factor and M>0; and x1 is the input parameter of the first function, representing the error between the target velocity signal acquired and the output velocity tracking signal by the nonlinear differential tracker.

[0117] The expression for the nonlinear differential tracker is:

[0118]

[0119] Where e0 is the error signal between the target velocity signal and the velocity tracking signal, and the initial value of e0 is 0; ω tr The velocity tracking signal; ω gi The target velocity signal is given; r is the velocity factor, which is a set parameter; if al Let α0 and δ0 represent the first function, and let α0 and δ0 be the first function if alThe setting parameters. In another exemplary embodiment, the initial value of e0 is 0, the setting value α0 is 0.25, the setting value δ0 is 0.2, and the setting value r is 9000.

[0120] In one exemplary embodiment, the extended state observer is used to process the error between the acquired actual velocity signal and the output feedback velocity signal based on a first function.

[0121] The expression for the first function is:

[0122]

[0123] Among them, if al Let λ represent the first function, λ be the amplitude of the sine function (λ>0), M be the velocity factor (M>0), and x2 be the input parameter of the first function, representing the error between the actual velocity signal acquired by the extended state observer and the feedback velocity signal output.

[0124] The expression for the extended state observer is:

[0125]

[0126] Where e is the error signal between the input and output data of the extended state observer, and the initial value of e is 0; ω ba The feedback speed signal; ω ac f(t) is the actual velocity signal; f(t) is the disturbance signal observed by the extended state observer; β1 and β2 are the output error gains; if al Let α and δ represent the first function, and let α and δ be the first function if al The setting parameters; b0 is the compensation factor, which is a setting parameter; i q The control current is given. In another exemplary embodiment, e is initially set to 0, α is set to 0.25, δ is set to 0.2, and r is set to 9000.

[0127] In this embodiment, formula (8) corresponds to the same function as formula (6) in the previous embodiment, the difference being that the input parameters are different.

[0128] In an exemplary embodiment, the expression for the linear feedback control law NLSEF is:

[0129]

[0130] Wherein, e1 is the error signal between the feedback speed signal and the speed tracking signal obtained by the linear feedback control law; ω ba The feedback speed signal; ω tr The speed tracking signal; iq0 These are intermediate parameters used to calculate i. q K is a constant representing the error gain coefficient; f(t) is the disturbance signal; b0 is the compensation factor, a set parameter; i q To control the current.

[0131] In the prior art, in a first-order active disturbance rejection controller system, the nonlinear error feedback f al The characteristic curve of the function is not smooth, especially in the region where the error is close to zero, which may cause fluctuations in the system, thereby affecting the stability and accuracy of the control system. In formula (10), the linear proportional gain (first function if) is used. al (Replacing the nonlinear f in the existing NLSEF technology) al The function yields the error gain coefficient K, which is then used to implement feedback control of the error through a linear proportional gain, thereby eliminating a nonlinear element. The linear proportional gain dynamically adjusts the control input based on the magnitude of the error, while avoiding the complexity and potential fluctuations caused by nonlinear elements.

[0132] In the above embodiments, the first function (if al The improvement principle and effect are as follows:

[0133] f al The nonlinear curve used for ESO allows for a suitable low gain in the large error range by adjusting λ; by adjusting M, the convergence speed of the error in the small error range and the switching range can be adjusted, thereby achieving an effective balance between disturbance rejection and jitter. Figure 7 f was displayed al and if al Comparison of curves, Figure 8 This displays a comparison of the error gain values. From Figure 7 and Figure 8 As can be seen from this, compared with the traditional f al Compared to functions, if al The function maintains approximately linearity across the switching interval while still achieving high gain in the small error range and low gain in the large error range, and the error-gain curve is smoother. This design makes the if... al The function can provide greater gain when the error is small, thus quickly fine-tuning the system to a stable state; while when the error is large, it provides smaller gain to avoid excessive system response, thereby effectively improving the stability and responsiveness of the system.

[0134] In SVPWM speed control systems for permanent magnet synchronous motors, traditional speed loop PI control suffers from drawbacks such as weak disturbance rejection capability, large overshoot, complex parameter tuning, and limited control accuracy. In contrast, an active disturbance rejection controller (ADRC) employing first-function processing significantly enhances the system's disturbance rejection capability and dynamic response speed, while simplifying the parameter tuning process and improving control accuracy. This improved ADRC is introduced into the first-order speed element of the SVPWM speed control system for permanent magnet synchronous motors, replacing PI control.

[0135] In terms of control performance, the active disturbance rejection control (ADRC) using the first function exhibits better speed control for PMSMs with large moments of inertia and high speeds. To explore the effects of using the first function (if...)... al Improved active disturbance rejection control and traditional active disturbance rejection control (using formula (4) f) al To assess the performance differences of the function processing, a larger moment of inertia and a higher rotational speed were set. The specific experimental parameters are shown in Table 1.

[0136] Table 1 Experimental parameters

[0137] parameter value parameter value Phase resistance (Ω) 0.005 Extreme logarithm 2 Armature inductance (H) 0.0005 Static friction (N·m) 0.0005 <![CDATA[Rotational inertia of the rotor (kg·m 2 )]]> 1 / 5 / 7.5 / 10 DC voltage (V) 800 Viscous damping (N·m·s) 0.0006

[0138] The reference rotational speeds were set to 6000 r / min and 8000 r / min, and the simulation results are as follows: Figures 9-14 As shown, in Figures 9-11 The image shows the speed response characteristics of the flywheel at a set speed of 6000 r / min. Figure 9 The corresponding rotor moment of inertia is 5 kg·m 2 , Figure 10 The corresponding rotor moment of inertia is 7.5 kg·m. 2 , Figure 11 The corresponding rotor moment of inertia is 10 kg·m 2 At this point, both control methods can enable the FESS to quickly reach the set speed. However, the improved method (based on the first function if) al The active disturbance rejection control (ADRC) exhibits a faster response speed. Furthermore, the results at a higher set speed of 8000 r / min are as follows... Figures 12-14 As shown, where, Figure 12 The corresponding rotor moment of inertia is 5 kg·m 2 , Figure 13 The corresponding rotor moment of inertia is 7.5 kg·m. 2 , Figure 14 The corresponding rotor moment of inertia is 10 kg·m 2 Improved version (based on the first function if) alThe active disturbance rejection control (ADRC) maintains a fast and stable dynamic response even under complex operating conditions with high speed and large moment of inertia. This demonstrates that the improved ADRC can ensure that flywheels with large moments of inertia and high speeds quickly reach the required speed during operation.

[0139] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A hybrid energy storage device, characterized in that, The hybrid energy storage device includes: a power battery, a first flywheel, a second flywheel, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a drive motor circuit; One end of the power battery is connected to one end of the second flywheel, one end of the third switch, one end of the fourth switch, and one end of the drive motor circuit, respectively. The other end of the power battery is connected to one end of the first switch; The other end of the first switch is connected to one end of the second switch and the other end of the drive motor circuit, respectively. The other end of the second switch is connected to the other end of the third switch, one end of the first flywheel, and one end of the sixth switch, respectively. The other end of the first flywheel is connected to the other end of the fourth switch and one end of the fifth switch, respectively. The other end of the sixth switch is connected to the other end of the second flywheel and the other end of the fifth switch, respectively.

2. The hybrid energy storage device according to claim 1, characterized in that, The first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are all insulated gate bipolar transistors.

3. A hybrid energy storage control system, characterized in that, The hybrid energy storage control system includes the hybrid energy storage device according to any one of claims 1-2, and a controller; the controller is used to control the switching states of the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch to respond to multiple operating modes of the hybrid energy storage device.

4. The hybrid energy storage control system according to claim 3, characterized in that, The operating modes include start mode, constant speed driving mode, acceleration or hill climbing mode, and braking mode. The controller is used for: In the startup mode, the first switch, the second switch, and the fifth switch are turned on, the third switch, the fourth switch, and the sixth switch are turned off, and the PWM signal of the second switch is adjusted to adjust the output voltage of the first flywheel and the second flywheel. In the constant speed driving mode, the first switch is turned on, and the second switch, the fifth switch, the third switch, the fourth switch, and the sixth switch are turned off. In the acceleration or hill-climbing mode, the first switch, the second switch, and the fifth switch are turned on, the third switch, the fourth switch, and the sixth switch are turned off, and the PWM signal of the second switch is adjusted to regulate the current. In the braking mode, the first switch is controlled to be disconnected, the second switch is controlled to be turned on, the PWM signal of the second switch is adjusted to adjust the output voltage of the first flywheel and the second flywheel, and the switching states of the fifth switch, the third switch, the fourth switch and the sixth switch are controlled according to the back induced electromotive force generated by the drive motor circuit, the voltage of the first flywheel and the voltage of the second flywheel.

5. The hybrid energy storage control system according to claim 4, characterized in that, In controlling the switching states of the fifth switch, the third switch, the fourth switch, and the sixth switch based on the back-induced electromotive force generated by the drive motor circuit, the voltage of the first flywheel, and the voltage of the second flywheel, the controller is configured to: Obtain the back induced electromotive force generated by the drive motor circuit; When the reverse induced electromotive force is greater than the sum of the voltage of the first flywheel and the voltage of the second flywheel, the fifth switch is turned on, and the fourth, third and sixth switches are turned off, so that the first flywheel and the second flywheel are connected in series. When the reverse induced electromotive force is less than or equal to the sum of the voltages of the first flywheel and the second flywheel, the fifth switch and the third switch are controlled to open, and the fourth switch and the sixth switch are controlled to open, so that the first flywheel and the second flywheel are connected in parallel.

6. The hybrid energy storage control system according to claim 3, characterized in that, The hybrid energy storage control system further includes an active disturbance rejection controller; the motors in the first flywheel and the second flywheel are permanent magnet synchronous motors; the active disturbance rejection controller is used to acquire the target speed signal and the actual speed signal of the permanent magnet synchronous motor, and to obtain the output current of the permanent magnet synchronous motor based on the target speed signal and the actual speed signal.

7. The hybrid energy storage control system according to claim 6, characterized in that, The active disturbance rejection controller includes a nonlinear differential tracker, an extended state observer, and a linear feedback control law; The nonlinear differential tracker is used to track the acquired target velocity signal to obtain a velocity tracking signal, and feeds the velocity tracking signal back to the linear feedback control law; The extended state observer is used to obtain a feedback speed signal based on the acquired actual speed signal and the control current of the permanent magnet synchronous motor, and then feeds the feedback speed signal back to the linear feedback control law. The linear feedback control law is used to acquire the feedback speed signal and the speed tracking signal, and to obtain and output the control current based on the feedback speed signal and the speed tracking signal. Then, the control current is fed back to the extended state observer; the control current is the output current of the permanent magnet synchronous motor.

8. The hybrid energy storage control system according to claim 7, characterized in that, The nonlinear differential tracker is used to process the error between the acquired target velocity signal and the output velocity tracking signal based on a first function; The expression for the first function is: Among them, if al Let λ represent the first function, where λ is the amplitude of the sine function and λ>0; M is the velocity factor and M>0; and x1 is the input parameter of the first function, representing the error between the target velocity signal acquired and the output velocity tracking signal by the nonlinear differential tracker. The expression for the nonlinear differential tracker is: Where e0 is the error signal between the target velocity signal and the velocity tracking signal, and the initial value of e0 is 0; ω tr The velocity tracking signal; ω gi The target velocity signal is given; r is the velocity factor, which is a set parameter; if al Let α0 and δ0 represent the first function, and let α0 and δ0 be the first function if al The setting parameters.

9. The hybrid energy storage control system according to claim 8, characterized in that, The extended state observer is used to process the error between the acquired actual velocity signal and the output feedback velocity signal based on a first function; The expression for the first function is: Among them, if al Let λ represent the first function, where λ is the amplitude of the sine function and λ>0; M is the velocity factor and M>0; and x2 is the input parameter of the first function, representing the error between the actual velocity signal acquired by the extended state observer and the feedback velocity signal output. The expression for the extended state observer is: Where e is the error signal between the input and output data of the extended state observer, and the initial value of e is 0; ω ba The feedback speed signal; ω ac f(t) is the actual velocity signal; f(t) is the disturbance signal observed by the extended state observer; β1 and β2 are the output error gains; if al Let α and δ represent the first function, and let α and δ be the first function if al The setting parameters; b0 is the compensation factor, which is a setting parameter; i q The control current is referred to here.

10. The hybrid energy storage control system according to claim 9, characterized in that, The expression for the linear feedback control law is: Where e1 is the error signal between the feedback speed signal and the speed tracking signal obtained by the linear feedback control law; ω ba The feedback speed signal; ω tr The speed tracking signal; i q0 These are intermediate parameters used to calculate i. q K is a constant representing the error gain coefficient; f(t) is the disturbance signal; b0 is the compensation factor, a set parameter; i q To control the current.

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