Electric braking control method and system under generator constant sub-current closed loop
By collecting stator current data in the generator and calculating the excitation voltage control reference value, the constant stator current closed-loop control is achieved, which solves the problem of reduced electrical braking efficiency under low speed conditions, and improves the stability and efficiency of braking torque.
Patent Information
- Application Number
- CN202411395597.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-08
- Publication Date
- 2024-12-31
AI Technical Summary
Under low speed conditions, the electrical braking efficiency of the generator is greatly reduced. The existing constant excitation current control method leads to a decrease in the stator current and a decrease in the braking torque, which makes it impossible to effectively achieve stable braking of the unit.
By controlling the excitation system of the generator to enter the electric braking operation condition, real-time data of the stator current is collected, the difference between the preset given value is determined, the excitation voltage control reference value is calculated based on the difference, and the constant current closed-loop control is realized to ensure excitation The system outputs the maximum excitation current at low speeds.
The electrical braking efficiency and accuracy are improved, the braking torque stability of the generator at low speeds is ensured, and the problem of braking torque is avoided.
Smart Images
Figure CN119231980A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of electrical braking of generators, and in particular to an electrical braking control method and system of a generator under a constant sub-current closed loop. Background Art
[0002] At present, large-scale hydro-turbine generators widely use electrical braking during shutdown. The method is as follows: after the hydro-turbine generator set is de-energized and demagnetized, when the speed of the unit drops to 50%-60%, the monitoring system sends an electrical braking input signal according to the set procedure, closes the three-phase short-circuit switch at the unit outlet, and starts the excitation system. Through the constant excitation current control method, a constant DC current is input into the rotor winding, an induced electromotive force is generated in the stator, and thus a short-circuit current is generated. This current generates a copper loss braking torque in the stator winding, causing the unit to decelerate and brake to stop.
[0003] The above-mentioned traditional electrical braking method has a disadvantage. Under the constant excitation current control mode, the stator current of the generator will decrease as the generator speed decreases. When the speed drops to a certain value, the braking torque reaches a maximum, and then it will decrease due to the continuous decrease in the stator current. When the speed is 0, the braking torque will also drop to 0. The electrical braking efficiency is greatly reduced under low speed conditions. Summary of the invention
[0004] The present application provides an electric braking control method and system under a generator constant sub-current closed loop, so as to at least solve the technical problem that the electric braking efficiency is greatly reduced under low speed conditions.
[0005] The first aspect of the present application provides an electric braking control method under a constant sub-current closed loop of a generator, the method comprising:
[0006] Controlling the excitation system of the generator to enter an electric braking condition and start excitation, and then collecting real-time data of the stator current of the generator;
[0007] Determine the difference between the real-time data of the stator current and a preset stator current given value;
[0008] Determine an excitation voltage control reference value of the excitation system according to the difference;
[0009] The excitation output of the excitation system under electric braking condition is controlled based on the excitation voltage control reference value.
[0010] Preferably, the controlling the excitation system of the generator to enter an electric braking state and start excitation comprises:
[0011] Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode;
[0012] The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
[0013] Preferably, the preset stator current given value is a rated stator current value during a short-circuit test.
[0014] Preferably, determining the excitation voltage control reference value of the excitation system according to the difference comprises:
[0015] A PID link calculation is performed based on the difference to obtain an excitation voltage control reference value of the excitation system.
[0016] Preferably, the method further comprises:
[0017] When the rotation speed of the generator is less than or equal to a rotation speed threshold, the excitation current output by the excitation system is controlled to be an allowable maximum value of the excitation current.
[0018] The second aspect of the present application provides an electric braking control system under a generator constant sub-current closed loop, comprising:
[0019] The acquisition module is used to control the excitation system of the generator to enter the electric braking state and start the excitation, and then acquire the real-time data of the stator current of the generator;
[0020] A first determination module, used to determine the difference between the stator current real-time data and a preset stator current given value;
[0021] A second determination module, configured to determine an excitation voltage control reference value of the excitation system according to the difference;
[0022] A control module is used to control the excitation output of the excitation system under electric braking conditions based on the excitation voltage control reference value.
[0023] Preferably, the acquisition module is also used for:
[0024] Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode;
[0025] The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
[0026] Preferably, the preset stator current given value is a rated stator current value during a short-circuit test.
[0027] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.
[0028] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.
[0029] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:
[0030] The present application proposes an electric braking control method and system under a generator constant current closed loop, the method comprising: controlling the excitation system of the generator to enter an electric braking condition and start excitation, and then collecting the real-time data of the stator current of the generator; determining the difference between the real-time data of the stator current and a preset stator current given value; determining the excitation voltage control reference value of the excitation system according to the difference; and controlling the excitation output of the excitation system under the electric braking condition based on the excitation voltage control reference value. The technical solution proposed in the present application improves the efficiency and accuracy of electric braking.
[0031] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:
[0033] Figure 1 A flowchart of an electric braking control method under a constant sub-current closed loop of a generator provided according to an embodiment of the present application;
[0034] Figure 2 A schematic diagram of PID link calculation according to an embodiment of the present application;
[0035] Figure 3 A first structural diagram of an electric braking control system under a generator constant sub-current closed loop provided according to an embodiment of the present application;
[0036] Figure 4 This is a second structural diagram of an electric braking control system under a generator constant sub-current closed loop provided according to an embodiment of the present application. DETAILED DESCRIPTION
[0037] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.
[0038] The present application proposes an electric braking control method and system under a generator constant current closed loop, the method comprising: controlling the excitation system of the generator to enter an electric braking condition and start excitation, and then collecting the real-time data of the stator current of the generator; determining the difference between the real-time data of the stator current and a preset stator current given value; determining the excitation voltage control reference value of the excitation system according to the difference; and controlling the excitation output of the excitation system under the electric braking condition based on the excitation voltage control reference value. The technical solution proposed in the present application improves the efficiency and accuracy of electric braking.
[0039] The following describes an electric braking control method and system of a generator under a constant sub-current closed loop according to an embodiment of the present application with reference to the accompanying drawings.
[0040] Embodiment 1
[0041] Figure 1 Flow chart of an electric braking control method under a generator constant sub-current closed loop according to an embodiment of the present application, such as Figure 1 As shown, the method includes:
[0042] Step 1: Control the excitation system of the generator to enter the electric braking state and start excitation, and then collect the real-time data of the stator current of the generator.
[0043] In the embodiment of the present disclosure, controlling the excitation system of the generator to enter an electric braking state and start excitation includes:
[0044] Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode;
[0045] The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
[0046] For example, 1-1: the excitation system enters the electric braking mode, and the control mode is switched to the constant sub-current closed-loop control mode; 1-2: close the short-circuit switch of the hydro-generator, the electric braking switch, and separate the excitation switch. The excitation system starts excitation in the above electric braking mode, and the generator stator current I under the electric braking state is collected. G Real-time data.
[0047] It should be noted that the constant sub-current closed-loop control mode should only take effect when the excitation system enters the electric braking mode and the short-circuit switch is detected to be in the closed position, otherwise the constant sub-current closed-loop control mode function should be locked.
[0048] The electrical braking mode is a stator three-phase short-circuit mode, which mainly relies on the resistance of the generator stator winding itself to consume energy.
[0049] Step 2: Determine the difference between the real-time data of the stator current and a preset stator current given value.
[0050] It should be noted that the preset stator current given value I G_REF It is the rated stator current value during short-circuit test.
[0051] The stator current I collected G Real-time data, so that after an inertia link, it is consistent with the stator current given value I preset in the electric braking process G_REF Difference ΔI G .
[0052] Step 3: Determine an excitation voltage control reference value of the excitation system according to the difference.
[0053] In the embodiment of the present disclosure, step 3 specifically includes:
[0054] A PID link calculation is performed based on the difference to obtain an excitation voltage control reference value of the excitation system, that is, a calculation result.
[0055] It should be noted that if Figure 2 As shown, according to the difference ΔI G , so that after passing through the PID link, the output excitation voltage control reference value Uk is used as the excitation output control under the electric braking condition of the excitation system, where: Figure 2 Where s is the complex frequency, T A is the time constant, K PG is the proportionality coefficient, K IG is the integration coefficient, K DG is the differential coefficient.
[0056] Step 4: Controlling the excitation output of the excitation system under electric braking conditions based on the excitation voltage control reference value.
[0057] It should be noted that, according to the excitation voltage control reference value, the pulse output of the excitation regulator is controlled to achieve the generator constant sub-current closed-loop control.
[0058] In an embodiment of the present disclosure, the method further includes:
[0059] When the rotation speed of the generator is less than or equal to a rotation speed threshold, the excitation current output by the excitation system is controlled to be an allowable maximum value of the excitation current.
[0060] It should be noted that the maximum allowable value of the excitation current is the maximum value of the excitation current that can be output stably for a long time during normal operation, that is, the maximum limit I f_MAX , the capacity limitation of the electric brake transformer is not considered here.
[0061] It should be noted that when the generator speed drops to the speed threshold (the speed threshold is determined based on the specific unit parameters), the excitation regulation pulse trigger angle has reached the minimum limit value, corresponding to the excitation current I f The maximum limit has been reached. f_MAX (Maximum Limit I f_MAX Generally, it is 1.1 times the rated excitation current), then the output limit I f_MAX .
[0062] The optimal control of the electric braking torque can be achieved under the closed-loop control mode of the constant sub-current of the generator.
[0063] In summary, the electrical braking control method under a constant sub-current closed loop of a generator proposed in this embodiment realizes the constant sub-current closed-loop control of the generator under electrical braking conditions, thereby realizing optimal control of the electrical braking torque and improving the electrical braking efficiency and accuracy.
[0064] Embodiment 2
[0065] Figure 3 FIG. 1 is a structural diagram of an electric braking control system under a generator constant sub-current closed loop according to an embodiment of the present application, such as Figure 3 As shown, the system comprises:
[0066] The acquisition module 100 is used to control the excitation system of the generator to enter the electric braking state and start the excitation, and then acquire the real-time data of the stator current of the generator.
[0067] A first determination module 200 is used to determine the difference between the real-time data of the stator current and a preset stator current given value;
[0068] The preset stator current given value is the rated stator current value during the short-circuit test.
[0069] The second determination module 300 is configured to determine an excitation voltage control reference value of the excitation system according to the difference.
[0070] The control module 400 is used to control the excitation output of the excitation system under the electric braking condition based on the excitation voltage control reference value.
[0071] In the embodiment of the present disclosure, the acquisition module 100 is also used for:
[0072] Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode;
[0073] The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
[0074] In the embodiment of the present disclosure, the second determining module 300 is further configured to:
[0075] A PID link calculation is performed based on the difference to obtain an excitation voltage control reference value of the excitation system.
[0076] In the embodiments of the present disclosure, Figure 4 As shown, the system also includes:
[0077] The optimization module 500 is used to control the excitation current output by the excitation system to be the maximum allowable value of the excitation current when the rotation speed of the generator is less than or equal to a rotation speed threshold.
[0078] In summary, the electrical braking control system under the constant sub-current closed loop of the generator proposed in this embodiment realizes the constant sub-current closed-loop control of the generator under the electrical braking condition, thereby realizing the optimal control of the electrical braking torque and improving the electrical braking efficiency and accuracy.
[0079] Embodiment 3
[0080] In order to implement the above embodiments, the present disclosure further proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in Embodiment 1 is implemented.
[0081] Embodiment 4
[0082] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.
[0083] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0084] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.
[0085] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present application.
Claims
1. An electrical braking control method under a generator constant sub-current closed loop, characterized in that: The method comprises: Controlling the excitation system of the generator to enter an electric braking condition and start excitation, and then collecting real-time data of the stator current of the generator; Determine the difference between the real-time data of the stator current and a preset stator current given value; Determine an excitation voltage control reference value of the excitation system according to the difference; The excitation output of the excitation system under electric braking condition is controlled based on the excitation voltage control reference value.
2. The method according to claim 1, characterized in that The controlling the excitation system of the generator to enter the electric braking state and start excitation comprises: Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode; The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
3. The method according to claim 1, characterized in that The preset stator current given value is the rated stator current value during the short-circuit test.
4. The method according to claim 1, characterized in that Determining the excitation voltage control reference value of the excitation system according to the difference comprises: A PID link calculation is performed based on the difference to obtain an excitation voltage control reference value of the excitation system.
5. The method according to claim 1, characterized in that The method further comprises: When the rotation speed of the generator is less than or equal to a rotation speed threshold, the excitation current output by the excitation system is controlled to be an allowable maximum value of the excitation current.
6. An electrical braking control system under a generator constant sub-current closed loop, characterized in that: The system comprises: The acquisition module is used to control the excitation system of the generator to enter the electric braking state and start the excitation, and then acquire the real-time data of the stator current of the generator; A first determination module, used to determine the difference between the stator current real-time data and a preset stator current given value; A second determination module, configured to determine an excitation voltage control reference value of the excitation system according to the difference; A control module is used to control the excitation output of the excitation system under electric braking conditions based on the excitation voltage control reference value.
7. The system according to claim 6, characterized in that The acquisition module is also used for: Controlling the excitation system to enter an electric braking mode, and at the same time switching the control mode of the excitation system to a constant sub-current closed-loop control mode; The short-circuit switch and the electric brake switch of the generator are closed, and the excitation switch is opened at the same time, so that the excitation system is excited in the electric brake mode.
8. The system according to claim 6, characterized in that The preset stator current given value is the rated stator current value during the short-circuit test.
9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 5 is implemented.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.