CN112909885A - Control method and device of variable frequency control circuit, computer equipment and storage medium - Google Patents

Control method and device of variable frequency control circuit, computer equipment and storage medium Download PDF

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Publication number
CN112909885A
CN112909885A CN202110233764.5A CN202110233764A CN112909885A CN 112909885 A CN112909885 A CN 112909885A CN 202110233764 A CN202110233764 A CN 202110233764A CN 112909885 A CN112909885 A CN 112909885A
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power supply
power
buffer
switch
frequency control
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CN202110233764.5A
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CN112909885B (en
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冯良
秦鹏
陈涛
潘伟恩
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Hitachi Building Technology Guangzhou Co Ltd
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Hitachi Building Technology Guangzhou Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/027—Details with automatic disconnection after a predetermined time
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/006—Calibration or setting of parameters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/04—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
  • Control Of Voltage And Current In General (AREA)

Abstract

The application relates to a control method and device of a variable frequency control circuit, computer equipment and a storage medium. The method comprises the following steps: obtaining the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum time length is obtained by calculation based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm. By adopting the method, the variable frequency control circuit can continuously work after the power supply is powered off.

Description

Control method and device of variable frequency control circuit, computer equipment and storage medium
Technical Field
The present application relates to the field of circuit protection technologies, and in particular, to a method and an apparatus for controlling a variable frequency control circuit, a computer device, and a storage medium.
Background
With the development of circuit protection technology, frequency conversion control circuits have appeared. The frequency conversion control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a frequency conversion control switch and a load. The power supply, the buffer switch, the variable frequency control switch and the load are sequentially connected to form a loop, the buffer resistor is connected with the buffer switch in parallel, and the energy storage capacitor is connected with a branch formed by connecting the variable frequency control switch and the load in series in parallel.
In the conventional technology, if the power supply is detected to be powered off, the buffer switch and the variable frequency control switch are disconnected, and the variable frequency control circuit stops working to protect the device. After the power supply is recovered, the frequency conversion control circuit starts to work again, and the alternating current with the fixed voltage and the fixed frequency is converted into the alternating current with the variable voltage or frequency.
However, the excessive voltage drop caused by some transient fluctuations may be eliminated in a short time, and unnecessary loss may be caused when the variable frequency control circuit directly stops operating each time, for example, the frequency control circuit is frequently turned on and off to increase the failure rate of the device, and the requirement of continuous operation cannot be met.
Disclosure of Invention
In view of the above, it is necessary to provide a method and an apparatus for controlling a variable frequency control circuit, a computer device, and a storage medium, which can make the variable frequency control circuit continuously operate after power failure.
A control method of a frequency conversion control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a frequency conversion control switch and a load, wherein the power supply, the buffer switch, the frequency conversion control switch and the load are sequentially connected to form a loop, the buffer resistor is connected with the buffer switch in parallel, and the energy storage capacitor is connected with a branch formed by connecting the frequency conversion control switch and the load in series in parallel; the method comprises the following steps: obtaining the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum time length is obtained by calculation based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
In one embodiment, the obtaining the maximum duration for the variable frequency control switch to continue the variable frequency control of the load after the power supply is powered off includes: acquiring a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered; when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out variable frequency control on the load, determining a first maximum time length from power failure to recovery of the power supply based on the first functional relation; when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, determining a second maximum time length from power failure to recovery of the power supply based on the second functional relation; and selecting a smaller value from the first maximum duration and the second maximum duration as the maximum duration for the variable frequency control switch to continue to carry out variable frequency control on the load after the power supply is powered off.
In one embodiment, the obtaining a first functional relationship of the voltage of the energy storage capacitor changing with time before the power supply recovers includes: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; and substituting the current of the variable frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
In one embodiment, the method further comprises: if the power supply is detected to be recovered and the power-off duration of the power supply is smaller than the maximum duration, starting to record the recovery duration of the power supply; determining the charging time from the power supply recovery to the buffer switch actuation according to the time from the power failure to the power recovery of the power supply; and if the recovery time of the power supply reaches the charging time, attracting the buffer switch.
In one embodiment, the determining the charging time period from the power restoration to the closing of the buffer switch according to the time period from the power failure to the power restoration comprises: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; substituting the voltage of the energy storage capacitor into the third functional relation as a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply; setting the power-off time of the power supply to be 0, and substituting the time length from power-off to recovery of the power supply into the fourth functional relation as the recovery time of the power supply to obtain the attraction time of the buffer switch; and determining the charging time from the power supply to the buffer switch attraction according to the attraction time of the buffer switch and the restoration time of the power supply.
In one embodiment, the turning off the frequency conversion control switch and alarming if the power restoration is not detected before the power-off duration of the power supply reaches the maximum duration includes: judging whether the disconnection time of the power supply reaches the maximum time; and if the disconnection time of the power supply reaches the maximum time, disconnecting the variable frequency control switch and giving an alarm.
In one embodiment, the method further comprises: and if the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value, closing the buffer switch.
A control device of a variable frequency control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a variable frequency control switch and a load, wherein the power supply, the buffer switch, the variable frequency control switch and the load are sequentially connected to form a loop, the buffer resistor is connected with the buffer switch in parallel, and the energy storage capacitor is connected with a branch formed by connecting the variable frequency control switch and the load in series in parallel; the device comprises: the acquisition module is used for acquiring the maximum time length for the variable frequency control switch to continue to carry out variable frequency control on the load after the power supply is powered off, and the maximum time length is obtained by calculation based on at least one of the minimum voltage for carrying out variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; the power-off judging module is used for judging whether the power supply is powered off or not; the buffer control module is used for only disconnecting the buffer switch and starting to record the power-off duration of the power supply when the power supply is detected to be powered off; the recovery judging module is used for judging whether the power supply is recovered; and the frequency conversion control module is used for disconnecting the frequency conversion control switch and giving an alarm when the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration.
A computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program: obtaining the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum time length is obtained by calculation based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of: obtaining the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum time length is obtained by calculation based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
The frequency conversion control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a frequency conversion control switch and a load, wherein the power supply, the buffer switch, the frequency conversion control switch and the load are sequentially connected to form a loop, and the power supply supplies power to the load. The buffer resistor is connected with the buffer resistor in parallel, the buffer switch can control the on-off of the buffer resistor, and the current can pass through the buffer resistor when the buffer switch is disconnected to protect the device. The frequency conversion control switch is connected with the load in series, the frequency conversion control switch can carry out frequency conversion control on the load, and the current passes through the load when the frequency conversion control switch is closed. The energy storage capacitor is connected in parallel with a branch formed by connecting the variable frequency control switch and the load in series, the energy storage capacitor can store certain electric energy when the power supply is powered on, and the electric energy is released to supply power to the load when the power supply is powered off, so that the variable frequency control switch can continue to carry out variable frequency control on the load.
By obtaining the maximum duration for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, whether the variable frequency control switch is turned off or not can be judged based on the maximum duration after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Specifically, after the maximum duration is obtained, whether the power supply is powered off is judged, and if the power supply is detected to be powered off, only the buffer switch is turned off, so that a device is protected. And judging whether the power supply is recovered or not, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, namely the power supply is not recovered when the power-off duration of the power supply reaches the maximum duration, the variable-frequency control switch cannot continue to carry out variable-frequency control on the load at the moment, and the variable-frequency control switch is disconnected and gives an alarm, so that the variable-frequency control is protected.
The maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor, the maximum duration of power failure of the power supply can be determined according to the actual requirement of normal operation of the frequency conversion control circuit, and adverse effects caused by continuous frequency conversion control of the frequency conversion control circuit after the power supply is powered off are avoided.
Drawings
FIG. 1 is a diagram illustrating an exemplary implementation of a method for controlling a variable frequency control circuit;
FIG. 2 is a diagram illustrating an exemplary embodiment of a control method for a variable frequency control circuit;
FIG. 3 is a diagram illustrating an exemplary embodiment of a method for controlling a variable frequency control circuit;
FIG. 4 is a flow chart illustrating a control method of the variable frequency control circuit according to an embodiment;
FIG. 5 is a timing diagram of various components of the variable frequency control circuit in one embodiment;
FIG. 6 is a flow chart illustrating a control method of the variable frequency control circuit according to another embodiment;
FIG. 7 is a block diagram showing a control apparatus of the variable frequency control circuit according to one embodiment;
FIG. 8 is a diagram illustrating an internal structure of a computer device according to an embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
The control method of the frequency conversion control circuit provided by the application can be applied to the application environment shown in fig. 1. The variable frequency control circuit comprises a power supply 10, a buffer switch 21, a buffer resistor 22, an energy storage capacitor 30, a variable frequency control switch 41, a load 42 and a first voltage converter 51. Two input ends of the first voltage converter 51 are respectively connected to the power supply 10, and two output ends of the first voltage converter 51 are respectively connected to the energy storage capacitor 30. The snubber resistor 22 is connected in parallel with the snubber switch 21 and then connected in series between the first voltage converter 51 and the power supply 10. The branch formed by the series connection of the variable frequency control switch 41 and the load 42 is connected in parallel with the energy storage capacitor 30.
The control method of the frequency conversion control circuit provided by the application can also be applied to the application environment shown in fig. 2. The variable frequency control circuit comprises a power supply 10, a buffer switch 21, a buffer resistor 22, an energy storage capacitor 30, a variable frequency control switch 41, a load 42, a first voltage converter 51 and a second voltage converter 52. Two input ends of the first voltage converter 51 are respectively connected to the power supply 10, and two output ends of the first voltage converter 51 are respectively connected to the energy storage capacitor 30. The snubber resistor 22 is connected in parallel with the snubber switch 21 and then connected in series between the first voltage converter 51 and the power supply 10. Two input terminals of the second voltage converter 52 are respectively connected to the energy storage capacitor 30, and two output terminals of the second voltage converter 52 are respectively connected to the load 42. The variable frequency control switch 42 is connected in series between the second voltage converter 52 and the energy storage capacitor 30.
The control method of the frequency conversion control circuit provided by the application can also be applied to the application environment shown in fig. 3. The variable frequency control circuit comprises a power supply 10, a buffer switch 21, a buffer resistor 22, an energy storage capacitor 30, a variable frequency control switch 41 and a load 42. The power source 10, the buffer switch 21, the variable frequency control switch 41 and the load 42 are connected in sequence to form a loop. The snubber resistor 22 is connected in parallel with the snubber switch 21. The energy storage capacitor 30 is connected in parallel with a branch formed by connecting the variable frequency control switch 41 and the load 42 in series.
The variable frequency control circuits shown in fig. 1, 2 and 3 are substantially the same, differing only in the voltage converter. The frequency conversion control circuit shown in fig. 1 is provided with one voltage converter, the frequency conversion control circuit shown in fig. 2 is provided with two voltage converters, and the frequency conversion control circuit shown in fig. 3 is provided with no voltage converter.
In the variable frequency control circuits shown in fig. 1, 2 and 3, the power supply 10 can supply an alternating current with a fixed voltage and frequency.
The buffer resistor 22 is connected in parallel with the buffer switch 21, and the buffer switch 21 can control the on/off of the buffer resistor 22. When the buffer switch 21 is closed, the two ends of the buffer resistor 22 are short-circuited by the buffer switch 21, and the current between the power supply 10 and the energy storage capacitor 30 flows through the buffer switch 21; when the snubber switch 21 is turned off, a current flows between the power supply 10 and the energy storage capacitor 30 through the snubber resistor 22.
The variable frequency control switch 41 is connected in series with the load 42, and the variable frequency control switch 41 can control the on-off of the load 42. When the variable frequency control switch 41 is closed, the current provided by the power supply 10 or the energy storage capacitor 30 can flow through the load 42; when the variable frequency control switch 42 is turned off, the current supplied by the power source 10 or the energy storage capacitor 30 cannot flow through the load 42.
The energy storage capacitor 30 is connected in parallel with a branch formed by connecting the variable frequency control switch 41 and the load 42 in series, and can continuously supply power to the load 42 when the power supply 10 is powered off. When the power supply 10 supplies power, the power supply 10 can also charge the energy storage capacitor 30 to store certain electric energy while supplying power to the load 42. When the power supply 10 is powered down, the energy storage capacitor 30 continues to supply power to the load 42 using the stored electrical energy. When the power supply 10 is restored, the power supply 10 supplies power to the load 42 again, and simultaneously charges the energy storage capacitor 30 again to store electric energy. The cycle is such that the load 42 is always powered and can continue to operate.
The control method in the embodiment mainly aims at the state control buffer switch and the variable frequency control switch of the power supply. Specifically, a control device executing the control method obtains the maximum duration for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum duration is calculated based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm. The control device may be, but not limited to, various processors or controllers, such as a Central Processing Unit (CPU), a controller, a single chip, a Complex Programmable Logic Device (CPLD), and the like.
In an embodiment, as shown in fig. 4, a control method of a variable frequency control circuit is provided, which is described by taking the method as an example applied to any one of the variable frequency control circuits in fig. 1, fig. 2 and fig. 3, and includes the following steps:
and step S402, acquiring the maximum duration of the variable frequency control switch for continuously carrying out variable frequency control on the load after the power supply is powered off.
The maximum duration is calculated based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor.
Specifically, for each variable frequency control circuit, the maximum time length is obtained for the first time, and the maximum time length is calculated and stored based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor, and the rated power of the buffer resistor. Thus, the maximum duration is obtained after the second time, and the maximum duration is directly read from the storage device.
In this embodiment, by obtaining the maximum duration for the variable frequency control switch to continue performing variable frequency control on the load after the power supply is powered off, whether to turn off the variable frequency control switch can be determined based on the maximum duration after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Step S404, judging whether the power supply is powered off.
Wherein, the power-off means whether the voltage of the power supply is continuously 0.
Specifically, the two ends of the power supply may be connected to a voltage sampling device to collect the voltage of the power supply. And if the power supply voltage acquired for multiple times is 0, judging that the power supply is powered off. And if the power supply voltage acquired at least once is not 0, judging that the power supply is electrified.
In this embodiment, by determining whether the power supply is powered off, a power failure can be timely discovered in the process of frequency conversion control, so as to perform corresponding processing and ensure the safe operation of the frequency conversion control circuit.
In one embodiment, the method further comprises: if it is detected that the power is not powered off, step S404 is executed again.
By detecting again when power failure is not detected, the detection can be timely found when power failure occurs.
In step S406, if the power failure is detected, only the buffer switch is turned off and the recording of the power failure duration of the power supply is started.
When the power supply is detected to be powered off, the buffer switch is only disconnected, and the variable-frequency control switch continues to perform variable-frequency control on the load. And simultaneously, recording the power-off duration of the power supply in real time to obtain the duration between the current moment and the moment when the power-off of the power supply is detected.
In particular, the buffer switch may be a relay. The movable contact and the normally closed contact of the relay are respectively connected with two ends of the buffer resistor, and the normally open contact of the relay is not connected. The movable contact of the relay is usually connected with the normally closed contact, and the buffer switch is closed; the control end of the relay is electrified, the movable contact of the relay becomes connected with the normally open contact, and the buffer switch is disconnected.
The moving contact and the normally open contact of the relay can be connected with the two ends of the buffer resistor respectively, and the normally closed contact of the relay is not connected. The control end of the relay is usually electrified, the moving contact of the relay is connected with the normally open contact, and the buffer switch is closed. If the power supply is detected to be cut off, the control end of the relay is stopped to be electrified, the movable contact of the relay is usually connected with the normally closed contact, and the buffer switch is disconnected.
When the power supply is detected to be powered off, the timer can be controlled to start timing, and the timed length of the timer is the power-off duration of the power supply.
In this embodiment, when power failure is detected, the snubber switch is turned off, and thus, a current flows from the snubber switch to the snubber resistor, and the device is protected by the snubber resistor. Meanwhile, the electric energy stored by the energy storage capacitor is used for replacing a power supply to supply power, so that the frequency conversion control switch continues to carry out frequency conversion control on the load, and unnecessary loss caused by direct work stop is avoided. In addition, the power-off duration of the power supply is recorded, and the variable-frequency control switch can be turned off in time when the power-off duration reaches the maximum duration so as to protect the device.
Step S408, judging whether the power supply is recovered.
Here, whether the power is restored or not means whether or not the voltage of the power is not 0.
Specifically, the two ends of the power supply may be connected to a voltage sampling device to collect the voltage of the power supply. And if the collected power supply voltage is not 0, judging that the power supply is recovered. And if the collected power supply voltage is 0, judging that the power supply is not recovered.
In this embodiment, after the power supply is powered off, whether the power supply is recovered is determined, so that the frequency conversion control circuit can be timely recovered to a normal state after the power supply is recovered.
And step S410, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable frequency control switch and giving an alarm.
Wherein not detecting that the power supply is restored before the power-off duration of the power supply reaches the maximum duration comprises: the power restoration is not detected until the power-off duration of the power reaches the maximum duration from the power-off of the power, and the power restoration is detected and the duration from the power-off of the power to the power restoration exceeds the maximum duration.
In one embodiment, if the power restoration is not detected before the power-off duration of the power supply reaches the maximum duration, the frequency conversion control switch is disconnected and an alarm is given, and the method comprises the following steps: judging whether the disconnection time of the power supply reaches the maximum time; and if the disconnection duration of the power supply reaches the maximum duration, disconnecting the variable frequency control switch and giving an alarm.
The power supply disconnection time length can be increased until the power supply is recovered, so whether the power supply is recovered or not is not needed to be considered, whether the power supply disconnection time length reaches the maximum time length or not is directly judged, and the variable frequency control switch is disconnected and an alarm is given as long as the power supply disconnection time length reaches the maximum time length, so that the variable frequency control circuit can be effectively protected.
Specifically, the variable frequency control switch may be a switching device, such as a field effect transistor, a triode, or the like. The first end and the second end of the switching device are respectively connected with the energy storage capacitor and the load. A first level signal is introduced to the control end of the switch device, the first end and the second end of the switch device are communicated, and the switch device is closed; and introducing a second level signal to the control end of the switching device, disconnecting the first end and the second end of the switching device, and disconnecting the switching device. One of the first level signal and the second level signal is a high level signal, and the other is a low level signal.
The alarm can be an audio alarm and/or a light alarm.
In this embodiment, when the power restoration is not detected before the power-off duration of the power supply reaches the maximum duration, if the variable-frequency control switch continues to perform variable-frequency control on the load, the voltage of the load when the energy storage capacitor discharges and the power frequency conversion of the buffer resistor when the energy storage capacitor charges may not meet the corresponding requirements, and at this time, the variable-frequency control switch is turned off and an alarm is given, so that the device can be protected.
In the control method of the variable frequency control circuit, the maximum duration for continuously carrying out variable frequency control on the load by the variable frequency control switch after the power supply is powered off is obtained, and whether the variable frequency control switch is switched off or not can be judged based on the maximum duration after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Specifically, after the maximum duration is obtained, whether the power supply is powered off is judged, and if the power supply is detected to be powered off, only the buffer switch is turned off, so that a device is protected. And judging whether the power supply is recovered or not, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, namely the power supply is not recovered when the power-off duration of the power supply reaches the maximum duration, the variable-frequency control switch cannot continue to carry out variable-frequency control on the load at the moment, and the variable-frequency control switch is disconnected and gives an alarm, so that the variable-frequency control is protected.
The maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor, the maximum duration of power failure of the power supply can be determined according to the actual requirement of normal operation of the frequency conversion control circuit, and adverse effects caused by continuous frequency conversion control of the frequency conversion control circuit after the power supply is powered off are avoided.
Referring to fig. 5, the whole process can be divided into the following stages:
at t0Before the moment, the power supply is normal. Power supply output signal U0Is sine wave, the voltage sampling result D is high level indicating normal, the buffer switch state SW is high level indicating closed, and the buffer resistance power PRIs 0, the voltage of the energy storage capacitor UCHeld at maximum, load power PLIndicating a normal high level.
At t0At that time, the power supply is off.
From t0Time t1Time of day, power supply output signal U0When the voltage is changed to 0, the voltage sampling result D is not capable of detecting the power failure in time due to the performance limitation of software and hardware, the high level is kept unchanged, the buffer switch state SW is also kept unchanged, and the buffer resistance power P is kept unchangedRAlso keeps 0 unchanged, and stores the capacitor voltage UCLoad power P begins to decrease due to discharge of energy storage capacitorLRemains high unchanged.
At t1At that time, a power outage is detected.
From t1Time t2Time of day, power supply output signal U0Keeping the voltage at 0, the voltage sampling result D changes to low level indicating abnormity due to power failure detection, the buffer switch state SW keeps high level unchanged due to software and hardware performance limitation and failure in timely disconnecting the buffer switch, and the buffer resistance power PRAlso keeps 0 unchanged, and stores the capacitor voltage UCContinues to decrease, the load power PLOr remain high.
At t2At that time, the snubber switch is turned off.
From t2Time t3Time of day, power supply output signal U0Holding 0, holding the voltage sampling result D at low level, turning the buffer switch state SW to low level indicating the disconnection due to the disconnection of the buffer switch, and buffering the resistance power PRThe voltage of the energy storage capacitor U is continuously 0 due to the power offCContinues to decrease, the load power PLOr remain high.
At t3At that time, power is restored.
From t3Time t4Time of day, power supply output signal U0Recovering to sine wave, the voltage sampling result D is not able to detect power failure in time due to software and hardware performance limitation, and keeps low level unchanged, the buffer switch state SW also keeps low level unchanged, and the buffer resistance power PRThe voltage U of the energy storage capacitor is reduced after jumping to the maximum value due to the recovery of the power supplyCAt the beginning of the rise, the load power PLOr remain high.
At t4At that time, a power restoration is detected.
From t4Time t5Time of day, power supply output signal U0Keeping the voltage sampling result D to be a normal high level due to the detection of the power restoration, keeping the buffer switch state SW unchanged at a low level due to the fact that the buffer switch can not be closed in time due to the software and hardware performance limitation, and buffering resistance power PRContinuing to decrease the voltage U of the energy storage capacitorCContinuously increasing to the maximum value, load power PLOr remain high.
At t5At that moment, the buffer switch is closed.
At t5After the moment, the power supply outputs a signal U0The sine wave is maintained, the voltage sampling result D is maintained at a high level, the buffer switch state SW is changed to a high level indicating the closing due to the closing of the buffer switch, and the buffer resistance power PRThe voltage of the energy storage capacitor U is changed into 0 due to the closing of the buffer switchCIs maintained asMaximum value, load power PLOr remain high.
In conclusion, the load power is always at a high level indicating normal in the whole process, the variable frequency control circuit can continuously work in the power-off process of the power supply, unnecessary loss caused by direct work stop every time can be avoided, the variable frequency control circuit is particularly suitable for instantaneous fluctuation which is automatically eliminated in a short time, the fault rate of devices can be reduced, and the requirement of continuous work is met.
In one embodiment, obtaining the maximum duration for the variable frequency control switch to continue variable frequency control of the load after the power supply is powered off comprises: acquiring a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered; when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out frequency conversion control on the load, determining a first maximum duration from power failure to recovery of the power supply based on a first functional relation; when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, determining a second maximum time length from power failure to recovery of the power supply based on a second functional relation; and selecting a smaller value from the first maximum duration and the second maximum duration as the maximum duration for continuously carrying out frequency conversion control on the load by the frequency conversion control switch after the power supply is powered off.
Wherein the first function relationship is uC(t)＝f1(t)，t0＜t≤t3，uC(t) is the voltage of the energy storage capacitor, t is the current time, t0At the moment of power-off, t3The moment when the power is restored.
The second function is
Figure BDA0002959800300000131
t＞t3P is the power of the buffer resistor, U0Is the voltage of the power supply, uC(t) is the voltage of the energy storage capacitor, R is the resistance value of the buffer resistor, t is the current time, t is3The moment when the power is restored.
In particular, in uC(t)≥UwCalculating t3To obtain a first maximum duration. Wherein, UwIs the minimum voltage for frequency conversion control of the load.
In that
Figure BDA0002959800300000132
Calculating t3To obtain a second maximum duration. Wherein, PR-PlusFor maximum instantaneous power allowed by the buffer resistance, PRRated power for the snubber resistor, t5To buffer the moment of switch closure, and t3Has corresponding functional relationship.
In this embodiment, on one hand, a first functional relationship that the voltage of the energy storage capacitor changes with time before the power supply recovers is obtained, and when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for performing frequency conversion control on the load, a first maximum time period from power failure to recovery of the power supply is determined based on the first functional relationship, so that it can be ensured that the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for performing frequency conversion control on the load when the power failure time period is within the maximum time period. On the other hand, a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered is obtained; when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, the second maximum time length from power-off to recovery of the power supply is determined based on the second functional relation, and the power of the buffer resistor is smaller than or equal to the maximum instantaneous power or the rated power of the buffer resistor when the power-off time length is within the maximum time length. And finally, selecting a smaller value from the first maximum time length and the second maximum time length as the maximum time length for the variable frequency control switch to continuously carry out variable frequency control on the load after the power supply is powered off, so that when the power-off time length is within the maximum time length, all parts of the variable frequency control circuit can normally work.
Optionally, obtaining a first functional relationship of the voltage of the energy storage capacitor changing with time before the power supply recovers includes: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; and substituting the current of the variable-frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
Wherein the third function relationship is
Figure BDA0002959800300000141
t≤t5Let t0C is the capacitance of the storage capacitor, U ═ 00Is the voltage of the power supply, uC(t) is the voltage of the energy storage capacitor, PLIs the power of the load, t is the current time, iR(t) is the current of the buffer resistor, t5The moment when the buffer switch is closed and the moment t when the power supply is recovered3Has corresponding functional relationship.
Specifically, when t is0＜t≤t3When i isRWhen (t) is 0, the first functional relationship can be obtained.
In this embodiment, a third functional relationship is established by using a connection relationship between each component in the frequency conversion control circuit. And simplifying the third functional relation by using a special value of the variable frequency control circuit at a specific moment to obtain the first functional relation.
In addition, the time t at which the snubber switch is closed5And time t of power restoration3The corresponding functional relationship can be obtained as follows:
at the first step, when t3＜t＜t5Then, the following functional relationship can be obtained:
Figure BDA0002959800300000142
wherein C is the capacitance of the energy storage capacitor, U0Is the voltage of the power supply, uC(t) is the voltage of the energy storage capacitor, PLIs the power of the load, t is the current time, t3For the moment of power restoration, iR(t) is the current of the buffer resistor, and R is the resistance value of the buffer resistor.
In the second step, the following functional relationship can be obtained by solving:
uC(t)＝f2(t，t3)，t3＜t＜t5；
wherein u isC(t) is the voltage of the energy storage capacitor, t is the current time, t3For the moment of power restoration, t5The moment when the buffer switch is closed.
And thirdly, the time for the voltage of the energy storage capacitor to be fully charged to be consistent with the voltage of the power supply is infinity. In order to avoid the buffer resistor from being burnt, the buffer switch can be properly pulled in advance.
By uC(t5)＝U010v, for example, the following functional relationship can be obtained:
uC(t5)＝f2(t5，t3)＝U0-10V；
wherein u isC(t5) For the energy-storage capacitor at t5Voltage at time t5To buffer the moment of switch closure, t3For the moment of power restoration, U0Is the voltage of the power supply.
The fourth step, when t is satisfied3＜t5In this case, the following functional relationship can be solved:
t5＝f3(t3)；
wherein, t5To buffer the moment of switch closure, t3The moment when the power is restored.
In one embodiment, the method further comprises: if the power supply recovery is detected and the power-off duration of the power supply is less than the maximum duration, starting to record the recovery duration of the power supply; determining the charging time from the power restoration to the closing of the buffer switch according to the time from the power failure to the restoration of the power; and if the recovery time of the power supply reaches the charging time, closing the buffer switch.
Wherein the time length from the power failure to the power restoration is the time length from the power failure time to the power restoration time.
The energy storage capacitor is continuously discharged in the process from power failure to recovery of the power supply, and the electric energy released by the energy storage capacitor can be determined based on the time length from power failure to recovery of the power supply. Since the capacitance supplemented by the energy storage capacitor should be consistent with the capacitance released by the energy storage capacitor, the capacitance supplemented by the energy storage capacitor is known. On the basis of this, the charging time of the energy storage capacitor can be determined. After the energy storage capacitor is charged, the buffer switch needs to be attracted, so that the frequency conversion control circuit is restored to the initial state. Therefore, the charging time period is the time period from the time of power restoration to the time of the actuation of the buffer switch.
Specifically, the timer may be controlled to start timing when the recovery time of the power supply starts to be recorded, and the time counted by the timer is the recovery time of the power supply.
In practical application, the recovery time of the power supply and the power-off time of the power supply can be respectively timed by different timers, so that confusion can be effectively avoided. The recovery time length of the power supply and the power-off time length of the power supply can also adopt the same timer, the power-off time length and the recovery time length of the power supply do not overlap, the timer is reset when the timing is started every time, and the implementation cost can be reduced.
In this embodiment, when it is detected that the power is restored and the power-off duration of the power is less than the maximum duration, the restoration duration of the power is recorded, and the charging duration from the power restoration to the actuation of the buffer switch is determined according to the duration from the power-off to the restoration of the power, so as to determine whether the restoration duration of the power reaches the charging duration. And when the recovery time of the power supply reaches the charging time, the buffer switch is closed. When the buffer switch is switched on, the voltage of the energy storage capacitor is consistent with the voltage of the power supply, and the voltage on the load cannot change suddenly, so that the load is effectively protected.
Optionally, determining a charging duration from power restoration to actuation of the buffer switch according to a duration from power failure to power restoration of the power supply includes: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; substituting the voltage of the energy storage capacitor into the third functional relation for a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply; setting the power-off time of the power supply as 0, and substituting the time length from power-off to recovery of the power supply as the recovery time of the power supply into the fourth functional relation to obtain the actuation time of the buffer switch; and determining the charging time from the power supply recovery to the buffer switch suction according to the suction time of the buffer switch and the recovery time of the power supply.
Wherein the third function relationship is
Figure BDA0002959800300000161
t≤t5Let t0C is the capacitance of the storage capacitor, U ═ 00Is the voltage of the power supply, uC(t) is the voltage of the energy storage capacitor, PLIs the power of the load, t is the current time, iR(t) is the current of the buffer resistor, t5The moment when the buffer switch is closed and the moment t when the power supply is recovered3Has corresponding functional relationship.
The fourth function relationship is t5＝f3(t3)，t5To buffer the moment of switch closure, t3The moment when the power is restored.
Specifically, at t3＜t＜t5Then, u can be obtained from the third functional relationshipC(t)＝f2(t，t3)，t3＜t＜t5，uC(t) is the voltage of the energy storage capacitor, t is the current time, t3For the moment of power restoration, t5The moment when the buffer switch is closed. The voltage of the energy storage capacitor is a fixed value when the buffer switch is switched on, and is uC(t5)＝U0And substituting-10V into the third functional relation to obtain a fourth functional relation. Setting the power-off time of the power supply to be 0, wherein the time length from power-off to power-on of the power supply is the time t of power supply power3Substituting the fourth function relationship to obtain the pull-in time t of the buffer switch5. The suction time t of the buffer switch5Minus the recovery time t of the power supply3And the charging time from the power supply recovery to the buffer switch actuation can be obtained.
In this embodiment, a third functional relationship is established by using a connection relationship between each component in the frequency conversion control circuit. And simplifying the third functional relation by using a special value of the variable frequency control circuit at a specific moment to obtain a fourth functional relation. And then setting the power-off time of the power supply as 0, and substituting the time length from power-off to recovery of the power supply as the recovery time of the power supply into the fourth functional relation to obtain the actuation time of the buffer switch. And finally, according to the suction time of the buffer switch and the recovery time of the power supply, the charging time from the power supply recovery to the suction of the buffer switch can be determined.
In one embodiment, the method further comprises: and if the recovery time length of the power supply does not reach the charging time length, continuously judging whether the recovery time length of the power supply reaches the charging time length.
The judgment is carried out again when the recovery time of the power supply does not reach the charging time, so that the buffer switch is timely attracted when the recovery time of the power supply reaches the charging time, and the frequency conversion control circuit is recovered to a normal state.
In one embodiment, the method further comprises: and if the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value, closing the buffer switch.
And the fixed value is the voltage of the energy storage capacitor after charging. For example, the voltage of the power supply minus 10V.
Specifically, the two ends of the capacitor may be connected to a voltage sampling device to collect the voltage of the capacitor.
In this embodiment, after detecting that the power is restored, the voltage of the energy storage capacitor is directly detected and compared with the fixed value, so as to quickly determine whether to pull in the buffer switch.
In one embodiment, as shown in fig. 6, an application example of a control method of a variable frequency control circuit is elaborated, which includes the following steps:
step S601, obtaining the maximum duration of the frequency conversion control switch for continuing to carry out frequency conversion control on the load after the power supply is powered off.
Step S602, detecting whether the power supply is powered off. If the power supply is detected not to be powered off, executing step S602; if power-off is detected, step S603 is performed.
And step S603, disconnecting the buffer switch and starting to record the power-off duration of the power supply.
Step S604, detecting whether the power is restored. If it is detected that the power is not recovered, performing step S605; if power restoration is detected, step S606 is performed.
Step S605, determine whether the power-off duration of the power supply exceeds the maximum duration. If the power-off duration of the power supply does not exceed the maximum duration, executing step S604; if the power-off duration of the power supply exceeds the maximum duration, step S607 is performed.
Step S606, determining whether the power-off duration of the power supply exceeds the maximum duration. If the power-off duration of the power supply does not exceed the maximum duration, executing step S608; if the power-off duration of the power supply exceeds the maximum duration, step S607 is performed.
And step S607, disconnecting the frequency conversion control switch and giving an alarm.
In step S608, the recording of the recovery time period of the power supply is started.
In step S609, it is determined whether the recovery time period of the power supply reaches the charging time period. If the recovery time of the power supply does not reach the charging time, executing the step S609; if the restoration period of the power reaches the charging period, step S610 is performed.
And step S610, attracting the buffer switch.
It should be understood that although the steps in the flowcharts of fig. 4 and 6 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 4 and 6 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed in turn or alternately with other steps or at least some of the other steps.
In one embodiment, as shown in fig. 7, a control device of a variable frequency control circuit is provided, the variable frequency control circuit includes a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a variable frequency control switch and a load, the power supply, the buffer switch, the variable frequency control switch and the load are sequentially connected to form a loop, the buffer resistor is connected in parallel with the buffer switch, and the energy storage capacitor is connected in parallel with a branch formed by connecting the variable frequency control switch and the load in series. The device includes: an obtaining module 701, a power failure judging module 702, a buffer control module 703, a recovery judging module 704 and a frequency conversion control module 705, wherein:
the obtaining module 701 is configured to obtain a maximum duration for the variable frequency control switch to continue performing variable frequency control on the load after the power supply is powered off, where the maximum duration is calculated based on at least one of a minimum voltage for performing variable frequency control on the load, a maximum instantaneous power of the buffer resistor, and a rated power of the buffer resistor.
And a power-off judging module 702, configured to judge whether the power supply is powered off.
And the buffer control module 703 is configured to, when power failure of the power supply is detected, only turn off the buffer switch and start recording the power failure duration of the power supply.
And a recovery judging module 704, configured to judge whether the power is recovered.
And the frequency conversion control module 705 is used for disconnecting the frequency conversion control switch and giving an alarm when the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration.
In the control device of the variable frequency control circuit, by acquiring the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, whether the variable frequency control switch is switched off or not can be judged based on the maximum time length after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Specifically, after the maximum duration is obtained, whether the power supply is powered off is judged, and if the power supply is detected to be powered off, only the buffer switch is turned off, so that a device is protected. And judging whether the power supply is recovered or not, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, namely the power supply is not recovered when the power-off duration of the power supply reaches the maximum duration, the variable-frequency control switch cannot continue to carry out variable-frequency control on the load at the moment, and the variable-frequency control switch is disconnected and gives an alarm, so that the variable-frequency control is protected.
The maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor, the maximum duration of power failure of the power supply can be determined according to the actual requirement of normal operation of the frequency conversion control circuit, and adverse effects caused by continuous frequency conversion control of the frequency conversion control circuit after the power supply is powered off are avoided.
In one embodiment, the obtaining module 701 includes: the device comprises an acquisition unit, a first determination unit, a second determination unit and a comprehensive determination unit, wherein: the obtaining unit is used for obtaining a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered. The first determining unit is used for determining a first maximum time length from power failure to recovery of the power supply based on a first functional relation when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out frequency conversion control on the load. And the second determining unit is used for determining a second maximum time length from power failure to recovery of the power supply based on the second functional relation when the power of the buffer resistor is less than or equal to the maximum instantaneous power of the buffer resistor or when the power of the buffer resistor is less than or equal to the rated power of the buffer resistor. And the comprehensive determining unit is used for selecting a smaller value from the first maximum time length and the second maximum time length as the maximum time length for continuously carrying out frequency conversion control on the load by the frequency conversion control switch after the power supply is powered off.
In one embodiment, the obtaining unit is configured to obtain a third functional relationship between the electric energy released by the energy storage capacitor, the electric energy consumed by the load, and the electric energy changed by the variable frequency control circuit after the power supply is turned off; and substituting the current of the variable-frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
In one embodiment, the apparatus further comprises: record module, duration determination module and first adsorption module, wherein: and the recording module is used for starting to record the recovery time length of the power supply when the power supply recovery is detected and the power-off time length of the power supply is less than the maximum time length. And the time length determining module is used for determining the charging time length from the power supply recovery to the buffer switch actuation according to the time length from the power failure to the power recovery of the power supply. And the first absorption module is used for absorbing the buffer switch when the recovery time of the power supply reaches the charging time.
In one embodiment, the duration determining module is configured to obtain a third functional relationship between the electric energy released by the energy storage capacitor, the electric energy consumed by the load, and the electric energy changed by the variable frequency control circuit after the power supply is turned off; substituting the voltage of the energy storage capacitor into the third functional relation for a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply; setting the power-off time of the power supply as 0, and substituting the time length from power-off to recovery of the power supply as the recovery time of the power supply into the fourth functional relation to obtain the actuation time of the buffer switch; and determining the charging time from the power supply recovery to the buffer switch suction according to the suction time of the buffer switch and the recovery time of the power supply.
In one embodiment, the variable frequency control module 705 includes: a judging unit and a disconnecting unit, wherein: and the judging unit is used for judging whether the disconnection duration of the power supply reaches the maximum duration. And the disconnection unit is used for disconnecting the variable frequency control switch and giving an alarm when the disconnection duration of the power supply reaches the maximum duration.
In one embodiment, the apparatus further comprises: and the second pull-in module is used for pulling in the buffer switch when the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value.
For specific limitations of the control device of the variable frequency control circuit, reference may be made to the above limitations on the control method of the variable frequency control circuit, which are not described herein again. All or part of each module in the control device of the variable frequency control circuit can be realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
In one embodiment, a computer device is provided, the internal structure of which may be as shown in FIG. 8. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a control method of a variable frequency control circuit.
Those skilled in the art will appreciate that the architecture shown in fig. 8 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program: obtaining the maximum duration of the variable frequency control switch for continuously carrying out variable frequency control on the load after the power supply is powered off, wherein the maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
In one embodiment, the processor, when executing the computer program, further performs the steps of: acquiring a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered; when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out frequency conversion control on the load, determining a first maximum duration from power failure to recovery of the power supply based on a first functional relation; when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, determining a second maximum time length from power failure to recovery of the power supply based on a second functional relation; and selecting a smaller value from the first maximum duration and the second maximum duration as the maximum duration for continuously carrying out frequency conversion control on the load by the frequency conversion control switch after the power supply is powered off.
In one embodiment, the processor, when executing the computer program, further performs the steps of: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; and substituting the current of the variable-frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
In one embodiment, the processor, when executing the computer program, further performs the steps of: if the power supply recovery is detected and the power-off duration of the power supply is less than the maximum duration, starting to record the recovery duration of the power supply; determining the charging time from the power restoration to the closing of the buffer switch according to the time from the power failure to the restoration of the power; and if the recovery time of the power supply reaches the charging time, closing the buffer switch.
In one embodiment, the processor, when executing the computer program, further performs the steps of: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; substituting the voltage of the energy storage capacitor into the third functional relation for a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply; setting the power-off time of the power supply as 0, and substituting the time length from power-off to recovery of the power supply as the recovery time of the power supply into the fourth functional relation to obtain the actuation time of the buffer switch; and determining the charging time from the power supply recovery to the buffer switch suction according to the suction time of the buffer switch and the recovery time of the power supply.
In one embodiment, the processor, when executing the computer program, further performs the steps of: judging whether the disconnection time of the power supply reaches the maximum time; and if the disconnection duration of the power supply reaches the maximum duration, disconnecting the variable frequency control switch and giving an alarm.
In one embodiment, the processor, when executing the computer program, further performs the steps of: and if the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value, closing the buffer switch.
In the computer device, by obtaining the maximum duration for the variable frequency control switch to continue performing variable frequency control on the load after the power supply is powered off, whether to turn off the variable frequency control switch can be determined based on the maximum duration after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Specifically, after the maximum duration is obtained, whether the power supply is powered off is judged, and if the power supply is detected to be powered off, only the buffer switch is turned off, so that a device is protected. And judging whether the power supply is recovered or not, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, namely the power supply is not recovered when the power-off duration of the power supply reaches the maximum duration, the variable-frequency control switch cannot continue to carry out variable-frequency control on the load at the moment, and the variable-frequency control switch is disconnected and gives an alarm, so that the variable-frequency control is protected.
The maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor, the maximum duration of power failure of the power supply can be determined according to the actual requirement of normal operation of the frequency conversion control circuit, and adverse effects caused by continuous frequency conversion control of the frequency conversion control circuit after the power supply is powered off are avoided.
In one embodiment, a computer-readable storage medium is provided, having a computer program stored thereon, which when executed by a processor, performs the steps of: obtaining the maximum duration of the variable frequency control switch for continuously carrying out variable frequency control on the load after the power supply is powered off, wherein the maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor; judging whether the power supply is powered off or not; if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply; judging whether the power supply is recovered; and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
In one embodiment, the computer program when executed by the processor further performs the steps of: acquiring a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered; when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out frequency conversion control on the load, determining a first maximum duration from power failure to recovery of the power supply based on a first functional relation; when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, determining a second maximum time length from power failure to recovery of the power supply based on a second functional relation; and selecting a smaller value from the first maximum duration and the second maximum duration as the maximum duration for continuously carrying out frequency conversion control on the load by the frequency conversion control switch after the power supply is powered off.
In one embodiment, the computer program when executed by the processor further performs the steps of: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; and substituting the current of the variable-frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
In one embodiment, the computer program when executed by the processor further performs the steps of: if the power supply recovery is detected and the power-off duration of the power supply is less than the maximum duration, starting to record the recovery duration of the power supply; determining the charging time from the power restoration to the closing of the buffer switch according to the time from the power failure to the restoration of the power; and if the recovery time of the power supply reaches the charging time, closing the buffer switch.
In one embodiment, the computer program when executed by the processor further performs the steps of: acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected; substituting the voltage of the energy storage capacitor into the third functional relation for a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply; setting the power-off time of the power supply as 0, and substituting the time length from power-off to recovery of the power supply as the recovery time of the power supply into the fourth functional relation to obtain the actuation time of the buffer switch; and determining the charging time from the power supply recovery to the buffer switch suction according to the suction time of the buffer switch and the recovery time of the power supply.
In one embodiment, the computer program when executed by the processor further performs the steps of: judging whether the disconnection time of the power supply reaches the maximum time; and if the disconnection duration of the power supply reaches the maximum duration, disconnecting the variable frequency control switch and giving an alarm.
In one embodiment, the computer program when executed by the processor further performs the steps of: and if the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value, closing the buffer switch.
In the storage medium, by obtaining the maximum duration for the variable frequency control switch to continue performing variable frequency control on the load after the power supply is powered off, whether to turn off the variable frequency control switch can be determined based on the maximum duration after the power supply is powered off. If the power-off duration of the power supply is less than the maximum duration, the variable-frequency control switch can continue to carry out variable-frequency control on the load at the moment without disconnecting the variable-frequency control switch. If the power-off duration of the power supply is greater than or equal to the maximum duration, the variable-frequency control switch cannot continue to perform variable-frequency control on the load at the moment, and the variable-frequency control switch needs to be disconnected.
Specifically, after the maximum duration is obtained, whether the power supply is powered off is judged, and if the power supply is detected to be powered off, only the buffer switch is turned off, so that a device is protected. And judging whether the power supply is recovered or not, if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, namely the power supply is not recovered when the power-off duration of the power supply reaches the maximum duration, the variable-frequency control switch cannot continue to carry out variable-frequency control on the load at the moment, and the variable-frequency control switch is disconnected and gives an alarm, so that the variable-frequency control is protected.
The maximum duration is obtained by calculation based on at least one of the minimum voltage for carrying out frequency conversion control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor, the maximum duration of power failure of the power supply can be determined according to the actual requirement of normal operation of the frequency conversion control circuit, and adverse effects caused by continuous frequency conversion control of the frequency conversion control circuit after the power supply is powered off are avoided.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in the embodiments provided herein can include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The control method of the frequency conversion control circuit is characterized in that the frequency conversion control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a frequency conversion control switch and a load, wherein the power supply, the buffer switch, the frequency conversion control switch and the load are sequentially connected to form a loop, the buffer resistor is connected with the buffer switch in parallel, and the energy storage capacitor is connected with a branch formed by connecting the frequency conversion control switch and the load in series in parallel; the method comprises the following steps:
obtaining the maximum time length for the variable frequency control switch to continue to perform variable frequency control on the load after the power supply is powered off, wherein the maximum time length is obtained by calculation based on at least one of the minimum voltage for performing variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor;
judging whether the power supply is powered off or not;
if the power supply is detected to be powered off, only disconnecting the buffer switch and starting to record the power-off duration of the power supply;
judging whether the power supply is recovered;
and if the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration, disconnecting the variable-frequency control switch and giving an alarm.
2. The method of claim 1, wherein obtaining the maximum duration for which the variable frequency control switch continues to perform variable frequency control on the load after the power supply is powered down comprises:
acquiring a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered and a second functional relation that the power of the buffer resistor changes along with time after the power supply is recovered;
when the voltage of the energy storage capacitor is greater than or equal to the minimum voltage for carrying out variable frequency control on the load, determining a first maximum time length from power failure to recovery of the power supply based on the first functional relation;
when the power of the buffer resistor is smaller than or equal to the maximum instantaneous power of the buffer resistor, or when the power of the buffer resistor is smaller than or equal to the rated power of the buffer resistor, determining a second maximum time length from power failure to recovery of the power supply based on the second functional relation;
and selecting a smaller value from the first maximum duration and the second maximum duration as the maximum duration for the variable frequency control switch to continue to carry out variable frequency control on the load after the power supply is powered off.
3. The method of claim 2, wherein obtaining the first functional relationship of the voltage of the energy storage capacitor over time before the power source is restored comprises:
acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected;
and substituting the current of the variable frequency control circuit into the third functional relation when the current is 0 before the power supply is recovered to obtain a first functional relation that the voltage of the energy storage capacitor changes along with time before the power supply is recovered.
4. A method according to claim 2 or 3, characterized in that the method further comprises:
if the power supply is detected to be recovered and the power-off duration of the power supply is smaller than the maximum duration, starting to record the recovery duration of the power supply;
determining the charging time from the power supply recovery to the buffer switch actuation according to the time from the power failure to the power recovery of the power supply;
and if the recovery time of the power supply reaches the charging time, attracting the buffer switch.
5. The method of claim 4, wherein determining the charging duration from the power restoration to the snubber switch pull-in based on the duration from the power outage to the power restoration comprises:
acquiring a third functional relation among the electric energy released by the energy storage capacitor, the electric energy consumed by the load and the electric energy changed by the variable frequency control circuit after the power supply is disconnected;
substituting the voltage of the energy storage capacitor into the third functional relation as a fixed value when the buffer switch is in the attraction state to obtain a fourth functional relation that the attraction time of the buffer switch changes along with the recovery time of the power supply;
setting the power-off time of the power supply to be 0, and substituting the time length from power-off to recovery of the power supply into the fourth functional relation as the recovery time of the power supply to obtain the attraction time of the buffer switch;
and determining the charging time from the power supply to the buffer switch attraction according to the attraction time of the buffer switch and the restoration time of the power supply.
6. The method according to any one of claims 1 to 3, wherein the step of turning off the frequency conversion control switch and alarming if the power restoration is not detected before the power-off duration of the power supply reaches the maximum duration comprises the steps of:
judging whether the disconnection time of the power supply reaches the maximum time;
and if the disconnection time of the power supply reaches the maximum time, disconnecting the variable frequency control switch and giving an alarm.
7. The method according to any one of claims 1 to 3, further comprising:
and if the power supply is detected to be recovered and the voltage of the energy storage capacitor reaches a fixed value, closing the buffer switch.
8. The control device of the frequency conversion control circuit is characterized in that the frequency conversion control circuit comprises a power supply, a buffer switch, a buffer resistor, an energy storage capacitor, a frequency conversion control switch and a load, wherein the power supply, the buffer switch, the frequency conversion control switch and the load are sequentially connected to form a loop, the buffer resistor is connected with the buffer switch in parallel, and the energy storage capacitor is connected with a branch formed by connecting the frequency conversion control switch and the load in series in parallel; the device comprises:
the acquisition module is used for acquiring the maximum time length for the variable frequency control switch to continue to carry out variable frequency control on the load after the power supply is powered off, and the maximum time length is obtained by calculation based on at least one of the minimum voltage for carrying out variable frequency control on the load, the maximum instantaneous power of the buffer resistor and the rated power of the buffer resistor;
the power-off judging module is used for judging whether the power supply is powered off or not;
the buffer control module is used for only disconnecting the buffer switch and starting to record the power-off duration of the power supply when the power supply is detected to be powered off;
the recovery judging module is used for judging whether the power supply is recovered;
and the frequency conversion control module is used for disconnecting the frequency conversion control switch and giving an alarm when the power supply recovery is not detected before the power-off duration of the power supply reaches the maximum duration.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method of any of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7.
CN202110233764.5A 2021-03-03 2021-03-03 Control method and device of variable frequency control circuit, computer equipment and storage medium Active CN112909885B (en)

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