阅读说明：本技术 一种恒功率灭磁装置、方法、存储介质及终端设备 (Constant-power de-excitation device and method, storage medium and terminal equipment ) 是由 史正军 梅桂华 宋萌 夏亚君 李力 梁飞 苏伟 钟国彬 罗嘉 程文锋 赵兵 蔡 于 2020-08-06 设计创作，主要内容包括：本发明实施例涉及一种恒功率灭磁装置、方法、存储介质及终端设备,包括励磁绕组、励磁电路和灭磁电路,灭磁电路包括灭磁开关、整流器、电流检测单元和控制驱动单元,灭磁开关的第一端分别与电流检测单元和励磁绕组的第一端连接,灭磁开关的第二端与整流器连接,控制驱动单元还与整流器连接,整流器还与励磁绕组的第二端连接,通过电流检测单元检测获得灭磁电路中的灭磁电流,控制驱动单元根据灭磁电流控制整流器产生电压源的输出反向电压施加在励磁绕组的两端,保证在灭磁过程中励磁绕组不产生过电压,使得该恒功率灭磁装置灭磁安全可靠又能实现快速灭磁,缩短灭磁的时间以及提高灭磁效率；解决了现有对于电机灭磁的速度低、安全性低的技术问题。(The embodiment of the invention relates to a constant-power field-suppression device, a method, a storage medium and terminal equipment, which comprise an excitation winding, an excitation circuit and a field-suppression circuit, wherein the field-suppression circuit comprises a field-suppression switch, a rectifier, a current detection unit and a control drive unit, the first end of the field-suppression switch is respectively connected with the current detection unit and the first end of the excitation winding, the second end of the field-suppression switch is connected with the rectifier, the control drive unit is also connected with the rectifier, the rectifier is also connected with the second end of the excitation winding, field-suppression current in the field-suppression circuit is obtained by the detection of the current detection unit, the control drive unit controls the rectifier to generate output reverse voltage of a voltage source according to the field-suppression current and applies the output reverse voltage to the two ends of the excitation winding, the field winding is ensured not to generate overvoltage in the field-suppression process, the field-suppression of, the demagnetization time is shortened and the demagnetization efficiency is improved; the technical problems of low de-excitation speed and low safety of the motor in the prior art are solved.)

1. A constant-power de-excitation device comprises an excitation winding and an excitation circuit connected with the excitation winding in parallel, and is characterized by further comprising a de-excitation circuit connected with the excitation winding in parallel, wherein the de-excitation circuit comprises a de-excitation switch, a rectifier, a current detection unit and a control drive unit connected with the current detection unit, the first end of the de-excitation switch is respectively connected with the current detection unit and the first end of the excitation winding, the second end of the de-excitation switch is connected with the rectifier, the control drive unit is further connected with the rectifier, and the rectifier is further connected with the second end of the excitation winding;

the current detection unit is used for detecting the de-excitation current of the de-excitation circuit and transmitting the de-excitation current to the control drive unit;

and the control driving unit is used for driving the rectifier to output reverse voltage to be applied to the excitation winding according to the de-excitation current.

2. The constant-power de-excitation device according to claim 1, wherein the control driving unit is used for controlling the time of triggering on or off of power electronics in the rectifier and controlling the magnitude of reverse voltage output by the rectifier.

3. The constant-power field suppression device according to claim 1, wherein the field suppression circuit further comprises a directional component, a first end of the directional component is connected with a first end of the excitation winding, and a second end of the directional component is connected with a first end of the field suppression switch.

4. The constant-power de-excitation device according to claim 3, wherein the directional component is a diode.

5. The constant-power field suppression device according to claim 1, wherein the excitation circuit is configured to provide an excitation current to the excitation winding, the excitation circuit includes an excitation switch connected to a first end of the excitation winding and an excitation power source connected in series to the excitation switch, and the excitation power source is further connected to a second end of the excitation winding.

6. A constant-power demagnetization method, wherein the constant-power demagnetization method based on the constant-power demagnetization device according to any one of claims 1 to 5 comprises the steps of:

the excitation switch is switched off, the field suppression switch is switched on, the field suppression circuit works, the field suppression current of the field suppression circuit is collected by adopting a current detection unit, and the field suppression current is used as a reference signal;

and the reference signal is transmitted to a control driving unit to drive a rectifier to generate a voltage source according to a reverse voltage relation, and the voltage source outputs reverse voltage and applies the reverse voltage to two ends of an excitation winding to realize demagnetization.

7. The constant-power demagnetization method according to claim 6, wherein the reverse voltage relation is: u. of_S(t)＝P_max/i_L(t) in the formula, u_s(t) is a reverse voltage, P_maxIs the maximum power of a constant-power de-excitation device i_LAnd (t) represents a field suppression current.

8. A computer-readable storage medium for storing computer instructions which, when run on a computer, cause the computer to perform the constant power demagnetization method according to claim 6.

9. Computer program, comprising program code for performing a constant power demagnetization method according to claim 6, when the computer program runs on a computer.

10. A terminal device comprising a processor and a memory;

the memory is used for storing program codes and transmitting the program codes to the processor;

the processor, according to instructions in the program code, is configured to perform the constant power de-excitation method according to claim 6.

Technical Field

The invention relates to the technical field of motor demagnetization, in particular to a constant-power demagnetization device, a constant-power demagnetization method, a storage medium and terminal equipment.

Background

Demagnetization is one of the important functions of the excitation system of the synchronous motor. When the motor normally runs, a rectifying device of an excitation system provides excitation current to a generator rotor through a de-excitation switch; when the motor is normally stopped or is stopped by accident, the excitation power supply is cut off by the de-excitation switch, and the de-excitation switch is opened to be connected with the de-excitation circuit to release the energy stored by the excitation winding. However, because the dc excitation winding of the motor usually has a large inductance characteristic, it is difficult to quickly transfer or extinguish the energy therein, and it is necessary to ensure that the voltage across the dc excitation winding cannot exceed a specified maximum overvoltage. On the premise of ensuring the safe operation of the motor, the de-excitation device can deal with different severe working conditions and quickly and reliably transfer or consume the energy stored in the direct-current excitation winding.

The field suppression speed and the safety in the field suppression process of the existing motor can not be simultaneously guaranteed, so that the field suppression speed is low, the field suppression time is long, the risk of damaging the motor exists, and the motor needs to be regularly maintained under the condition.

Disclosure of Invention

The embodiment of the invention provides a constant-power de-excitation device, a constant-power de-excitation method, a storage medium and terminal equipment, which are used for solving the technical problems of low de-excitation speed and low safety of the existing motor.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

a constant-power de-excitation device comprises an excitation winding and an excitation circuit connected with the excitation winding in parallel, and further comprises a de-excitation circuit connected with the excitation winding in parallel, wherein the de-excitation circuit comprises a de-excitation switch, a rectifier, a current detection unit and a control drive unit connected with the current detection unit, the first end of the de-excitation switch is respectively connected with the current detection unit and the first end of the excitation winding, the second end of the de-excitation switch is connected with the rectifier, the control drive unit is further connected with the rectifier, and the rectifier is further connected with the second end of the excitation winding;

the current detection unit is used for detecting the de-excitation current of the de-excitation circuit and transmitting the de-excitation current to the control drive unit;

and the control driving unit is used for driving the rectifier to output reverse voltage to be applied to the excitation winding according to the de-excitation current.

Preferably, the control driving unit is used for controlling the time of triggering on or off of the power electronic device in the rectifier and controlling the reverse voltage output by the rectifier.

Preferably, the de-excitation circuit further comprises an orientation component, a first end of the orientation component is connected with a first end of the excitation winding, and a second end of the orientation component is connected with a first end of the de-excitation switch.

Preferably, the directional component is a diode.

Preferably, the excitation circuit is configured to provide an excitation current to the excitation winding, the excitation circuit includes an excitation switch connected to a first end of the excitation winding and an excitation power supply connected in series to the excitation switch, and the excitation power supply is further connected to a second end of the excitation winding.

The invention also provides a constant-power de-excitation method, which comprises the following steps of:

the excitation switch is switched off, the field suppression switch is switched on, the field suppression circuit works, the field suppression current of the field suppression circuit is collected by adopting a current detection unit, and the field suppression current is used as a reference signal;

and the reference signal is transmitted to a control driving unit to drive a rectifier to generate a voltage source according to a reverse voltage relation, and the voltage source outputs reverse voltage and applies the reverse voltage to two ends of an excitation winding to realize demagnetization.

Preferably, the reverse voltage relation is: u. of_S(t)＝P_max/i_L(t) in the formula, u_s(t) is a reverse voltage, P_maxIs the maximum power of a constant-power de-excitation device i_LAnd (t) represents a field suppression current.

The present invention also provides a computer-readable storage medium for storing computer instructions which, when run on a computer, cause the computer to perform the constant power demagnetization method described above.

The present invention also provides a computer program, including program code for performing the constant power demagnetization method described above when the computer program runs on a computer.

The invention also provides terminal equipment, which comprises a processor and a memory;

the memory is used for storing program codes and transmitting the program codes to the processor;

the processor is used for executing the constant power de-excitation method according to instructions in the program codes.

According to the technical scheme, the embodiment of the invention has the following advantages:

1. the constant-power de-excitation device obtains de-excitation current in the de-excitation circuit through detection of the current detection unit, controls the driving unit to control the rectifier to generate output reverse voltage of the voltage source according to the de-excitation current and applies the output reverse voltage to two ends of the excitation winding, and ensures that the excitation winding does not generate overvoltage in the de-excitation process, so that the de-excitation of the constant-power de-excitation device is safe and reliable, quick de-excitation can be realized, the de-excitation time is shortened, and the de-excitation efficiency is improved; the technical problems of low de-excitation speed and low safety of the motor in the prior art are solved.

2. The constant-power field suppression method works through a field suppression circuit of a constant-power field suppression device, a current detection unit detects and obtains field suppression current in the field suppression circuit, a control driving unit controls a rectifier to generate a voltage source according to the field suppression current, and the control driving unit controls the voltage source to output reverse voltage to be applied to two ends of an excitation winding according to a reverse voltage relation, so that the excitation winding is ensured not to generate overvoltage in the field suppression process, field suppression can be performed quickly, and the technical problems of low field suppression speed and low safety of the existing motor are solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a frame diagram of a constant power field suppression device according to an embodiment of the present invention.

Fig. 2 is a flowchart illustrating steps of a constant power demagnetization method according to an embodiment of the present invention.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

At present, the main field suppression modes of the large-scale motor comprise field suppression switch field suppression and inversion field suppression; the current flowing through the field suppression switch is transferred to other energy consumption/storage devices by using the current breaking capacity of the field suppression switch (namely, a circuit breaker). The most common form is that a large-scale field-suppression switch and a field-suppression resistor are added, namely the field-suppression resistor is not connected to an exciting current loop when in normal operation, the field-suppression resistor is rapidly put into the field-suppression switch when in field suppression, a current path is formed between the field-suppression resistor and a rotor exciting winding, and magnetic field energy is converted into the field-suppression resistor to generate heat. The materials can be divided into linear resistance demagnetization and nonlinear resistance demagnetization according to different demagnetization resistance materials, and the materials are simply called linear demagnetization and nonlinear demagnetization. The linear de-excitation adopts a linear resistor, is simple and reliable, is very easy to use and maintain, but has the defects of low de-excitation speed and serious de-excitation tailing, and when de-excitation under the most serious working condition is considered, overvoltage threatening the insulation of a motor rotor can be generated, and the smooth current conversion of a de-excitation switch is seriously influenced. The nonlinear resistor material mainly comprises SiC and ZnO, the nonlinear de-excitation has the advantage of high de-excitation speed, but the nonlinear de-excitation has the defect that the characteristics of the nonlinear resistor are easy to change after being wetted and after being wetted for a long time, the aging problem exists, a single nonlinear resistor often cannot meet the requirements, a plurality of nonlinear resistors need to be connected in series or in parallel, the characteristics of ZnO valve plates with different parallel branches change along with the increase of de-excitation times and the lengthening of service life, the current-sharing/energy-sharing characteristics of the ZnO valve plates are increasingly poor, if the ZnO valve plates are not regularly checked, hidden dangers are left for the de-excitation of a motor under the severe working condition, and therefore the maintenance workload is greatly increased.

For the inversion demagnetization, when the motor is normally started and stopped, the inversion working state of the three-phase fully-controlled bridge of the excitation power supply is utilized, the control angle alpha is changed from the rectification running state of less than 90 degrees to a certain proper angle with alpha larger than 90 degrees suddenly, the polarity of the excitation current is changed at the moment, the excitation current is applied to the excitation winding in a counter potential mode, and the rotor current is quickly attenuated to zero in the demagnetization process. The de-excitation mode quickly feeds the stored energy of the motor rotor back to an alternating current side power supply of the three-phase fully-controlled bridge, does not need a discharge resistor or an arc extinguishing grid, and is a simple, convenient and practical de-excitation method. Because the counter potential generated during inversion of the three-phase fully-controlled bridge during inversion demagnetization is in direct proportion to the power supply potential at the alternating current side, the value of the counter potential is limited to a certain extent, and meanwhile, the counter potential is reduced to a certain extent due to the limitation of the maximum control max (or the minimum inversion angle min) set for preventing inversion overturn. Therefore, the inverter de-excitation is independently limited by the voltage of an alternating current power supply, the exciting current is linearly reduced during the inverter de-excitation, but the counter potential value applied during the inverter is smaller than that of the arc extinguishing grid de-excitation mode, so that the current attenuation rate is smaller, the de-excitation time is relatively longer, but the overvoltage multiple is also very low, the inverter de-excitation has the advantages of no contact, no arcing and no generation of a large amount of heat, and the de-excitation is reliable.

The embodiment of the application provides a constant-power field-suppression device, a constant-power field-suppression method, a storage medium and a terminal device, and the constant-power field-suppression device has the advantages of high field-suppression speed, simplicity in control, safety, reliability and the like by applying adjustable reverse voltage sources to two ends of an excitation winding, and is used for solving the technical problems of low field-suppression speed and low safety of the existing motor. In this embodiment, the constant power field suppression device, the constant power field suppression method, the storage medium, and the terminal device are applied to the motor as a case.