CN116505491A - Fixed-frequency alternating current circuit, voltage fluctuation protection method and device thereof and storage medium - Google Patents

Fixed-frequency alternating current circuit, voltage fluctuation protection method and device thereof and storage medium Download PDF

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Publication number
CN116505491A
CN116505491A CN202310507614.8A CN202310507614A CN116505491A CN 116505491 A CN116505491 A CN 116505491A CN 202310507614 A CN202310507614 A CN 202310507614A CN 116505491 A CN116505491 A CN 116505491A
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China
Prior art keywords
current
contactor
alternating current
control end
working state
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Inventor
房金志
肖威
李建国
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Guangdong New Energy Technology Development Co Ltd
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Guangdong New Energy Technology Development Co Ltd
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Priority to CN202310507614.8A priority Critical patent/CN116505491A/en
Publication of CN116505491A publication Critical patent/CN116505491A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
    • H02H7/222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for switches
    • 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
    • H02H3/08—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 responsive to excess current
    • 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
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Protection Of Static Devices (AREA)

Abstract

The invention discloses a fixed-frequency alternating current circuit, a voltage fluctuation protection method, a device and a storage medium thereof, wherein a first control end of an alternating current contactor of the fixed-frequency alternating current circuit is electrically connected with one end of a current sensitive element through a second control end, and the other end of the current sensitive element is connected with a zero line of a fixed-frequency alternating current power supply; the voltage fluctuation protection method comprises the following steps: acquiring a loop current signal between a first control end and a second control end based on the current sensitive element; determining the current working state of the alternating current contactor according to the loop current signal; the current working state comprises a normal working state and an abnormal working state; and controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor. The technical scheme of the invention can prevent the coil loop current from being overlarge due to unstable fixed-frequency alternating current power supply voltage, thereby leading the coil temperature of the alternating current contactor to rise and be burnt.

Description

Fixed-frequency alternating current circuit, voltage fluctuation protection method and device thereof and storage medium
Technical Field
The present invention relates to the field of circuit protection technologies, and in particular, to a fixed frequency ac circuit, and a voltage fluctuation protection method, apparatus, and storage medium thereof.
Background
The compressor of the fixed-frequency air-source heat pump unit is usually controlled to be on-off by adopting an alternating-current contactor, and the protection measure of the compressor in the prior art is generally combined protection of the alternating-current contactor and a thermal relay or combined protection of the alternating-current contactor and a current transformer, wherein the two protection methods are current protection devices.
However, in the region with larger power grid voltage fluctuation, the condition that the alternating current contactor is burnt out due to the fact that the temperature of a coil is too high caused by the larger power grid voltage fluctuation often happens, and even the compressor cannot be disconnected due to the fact that plastic parts of the alternating current contactor are deformed and blocked, so that serious accidents of burning out the compressor are caused, and the operation safety and stability of the compressor are affected.
Disclosure of Invention
The invention provides a fixed-frequency alternating current circuit, a voltage fluctuation protection method, a device and a storage medium thereof, which are used for solving the problem that coil loop current is overlarge due to unstable fixed-frequency alternating current power supply voltage, so that the coil temperature of an alternating current contactor is increased and the coil is easy to burn.
In a first aspect, the present invention provides a voltage fluctuation protection method for a fixed frequency ac circuit, where the fixed frequency ac circuit includes an ac contactor and a current sensing element; the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply; the voltage fluctuation protection method comprises the following steps:
acquiring a loop current signal between the first control end and the second control end based on the current sensing element;
determining the current working state of the alternating current contactor according to the loop current signal; the current working state comprises a normal working state and an abnormal working state;
and controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor.
Optionally, determining the current working state of the ac contactor according to the loop current signal includes:
judging whether the loop current signal is smaller than a current threshold value or not;
if yes, determining that the current working state of the alternating current contactor is a normal working state.
Optionally, if the loop current signal is greater than or equal to the current threshold, determining that the current working state of the ac contactor is an abnormal working state.
Optionally, when the current working state of the ac contactor is a normal working state, controlling the on-off time of the ac contactor includes:
acquiring an electricity utilization signal of the alternating current electricity utilization load;
when the power utilization signal of the alternating current power utilization load is an enabling signal, a first preset voltage is provided for the first control end, so that the alternating current contactor is in a conducting state.
Optionally, when the power utilization signal of the ac power utilization load is a non-enabling signal, a second preset voltage is provided to the first control end, so that the ac contactor is in an off state.
Optionally, when the current working state of the ac contactor is an abnormal working state, controlling the on-off time of the ac contactor includes:
providing a second preset voltage for the first control end so as to enable the alternating current contactor to be in an off state, and timing the current off time of the alternating current contactor;
when the current disconnection time of the alternating current contactor reaches the preset time, a first preset voltage which enables the alternating current contactor to be in a conducting state is provided for the first control end, and loop current signals between the first control end and the second control end are acquired based on the current sensing element in a return mode.
Optionally, after determining the current operating state of the ac contactor, the method further includes:
and controlling a display device to display the current working state of the alternating current contactor.
In a second aspect, the present invention provides a voltage fluctuation protection device for a fixed frequency ac circuit, the fixed frequency ac circuit including an ac contactor and a current sensing element; the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply; the voltage fluctuation protection device includes:
the loop current signal acquisition module is used for acquiring a loop current signal between the first control end and the second control end based on the current sensitive element;
the working state determining module is used for determining the current working state of the alternating current contactor according to the loop current signal; the working states comprise a normal working state and an abnormal working state;
and the control module is used for controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor.
In a third aspect, the present invention provides a fixed frequency ac circuit comprising: an ac contactor, a current sensing element, and a controller;
the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply;
the controller is used for executing the voltage fluctuation protection method of the constant-frequency alternating current circuit.
In a fourth aspect, the present invention provides a computer-readable storage medium storing computer instructions for causing a processor to execute a method for protecting against voltage fluctuations in a fixed frequency ac circuit as described in any one of the preceding claims.
According to the technical scheme, the loop current signal between the first control end and the second control end of the alternating-current contactor is obtained based on the current sensitive element, so that the current working state of the alternating-current contactor is determined according to the loop current signal, and the on-off time of the alternating-current contactor is controlled according to the current working state of the alternating-current contactor, so that when the loop current between the first control end and the second control end of the alternating-current contactor is overlarge due to unstable fixed-frequency alternating-current power supply voltage, the alternating-current contactor can be timely controlled to be disconnected, and the condition that the loop temperature between the first control end and the second control end of the alternating-current contactor is raised to burn the alternating-current contactor is prevented, so that the fixed-frequency alternating-current circuit cannot work normally is avoided; meanwhile, the first control end of the alternating current contactor is electrically connected with one end of the current sensing element through the second control end, the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply, loop current signals between the first control end and the second control end of the alternating current contactor are obtained based on the current sensing element, and the loop current signals between the first control end and the second control end of the alternating current contactor can be obtained based on the current sensing element without complex wiring.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of a fixed frequency ac circuit according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram showing the current-resistance characteristics of a current sensor according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of voltage-voltage characteristics of a coil of an ac contactor according to a second embodiment of the present invention;
fig. 4 is a flowchart of a voltage fluctuation protection method of a constant frequency ac circuit according to a second embodiment of the present invention;
fig. 5 is a flowchart of a voltage fluctuation protection method of a constant frequency ac circuit according to a third embodiment of the present invention;
fig. 6 is a schematic structural diagram of a voltage fluctuation protection device for a constant-frequency ac circuit according to a fifth embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
In this embodiment, the fixed frequency ac circuit may include, but is not limited to, a single phase ac circuit and a three phase ac circuit. When the fixed-frequency alternating current circuit is a single-phase alternating current circuit, the fixed-frequency alternating current power supply is correspondingly a single-phase alternating current power supply, and the alternating current contactor is a single-phase alternating current contactor; when the fixed-frequency alternating current circuit is a single-phase alternating current circuit, the fixed-frequency alternating current power supply is correspondingly a three-phase alternating current power supply, and the alternating current contactor is a three-phase alternating current contactor. Next, this embodiment will be described taking a fixed-frequency ac circuit as an example of a three-phase ac circuit.
Fig. 1 is a block diagram of a fixed frequency ac circuit according to an embodiment of the present invention. The embodiment of the invention provides a fixed-frequency alternating current circuit, which is shown by referring to fig. 1, and comprises an alternating current contactor 1, a current sensitive element 2 and a controller (not shown in the figure); the alternating current contactor 1 comprises an input end 11, an output end 12, a first control end 13 and a second control end 14; the input end 11 is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end 12 is electrically connected with each phase of the alternating current power utilization load 3 in a one-to-one correspondence manner; the first control end 13 is electrically connected with one end of the current sensing element 2 through the second control end 14, and the other end of the current sensing element 2 is connected with a zero line of a fixed-frequency alternating current power supply; the controller is used for executing the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by any embodiment of the invention.
The first control end 13 of the ac contactor 1 is electrically connected with one end of the current sensing element 2 through the second control end 14, and the other end of the current sensing element 2 is electrically connected with a zero line of a constant-frequency ac power supply, so that when a first preset voltage is provided to the first control end 13 of the ac contactor 1, the first control end 13 and the second control end 14 of the ac contactor 1 are in a conducting state, and an armature of the ac contactor 1 is attracted, so that the input end 11 and the output end 12 of the ac contactor 1 are conducted, and the ac load 3 is in a power-on state; the first preset voltage may be a rated voltage of a coil of the ac contactor 1. When the controller executes the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by the embodiment of the invention, loop current signals between the first control end 13 and the second control end 14 of the alternating current contactor 1 can be obtained through the current sensing element 2, so that the current working state of the alternating current contactor 1 can be determined according to the loop current signals, the on-off time of the alternating current contactor 1 can be controlled according to the current working state of the alternating current contactor 1, and the problem that the loop current between the first control end 13 and the second control end 14 of the alternating current contactor 1 is overlarge due to unstable constant-frequency alternating current power supply voltage, so that the alternating current contactor 1 is burnt can be effectively solved.
The current sensing element 2 may include, but is not limited to, a resistor sensitive to a current, and referring to fig. 2, the state of the current sensing element 2 may include a low-resistance state and a high-resistance state, wherein when the current flowing through the current sensing element 2 is lower than a certain current I, the current sensing element 2 is in the low-resistance state, and when the current flowing through the current sensing element 2 is higher than the certain current I, the current sensing element 2 is in the high-resistance state; for example, the current sensing element 2 may be a positive temperature coefficient thermistor; in an exemplary embodiment, the current sensor 2 may be a high molecular ptc thermistor, where a loop current signal between the first control terminal 13 and the second control terminal 14 may be converted into a resistance value of the current sensor, when the loop current between the first control terminal 13 and the second control terminal 14 is greater, the resistance of the current sensor 2 may be caused to be greater, and when the loop current is greater than or equal to a switching current of the current sensor 2, the resistance of the current sensor 2 may be instantaneously increased to present a high resistance state, so that the loop current is instantaneously reduced, and the ac contactor 1 is in an off state.
It will be appreciated that the larger the voltage ripple between the first control terminal 13 and the second control terminal 14, the larger the loop current between the first control terminal 13 and the second control terminal 14, and therefore the current sensing element 2 with the corresponding switching current may be selected for use according to the acceptable voltage ripple range of the fixed frequency ac circuit. In an exemplary embodiment, referring to fig. 3, when the voltage Uc between the first control terminal 13 and the second control terminal 14 is between 0.7U and 1.3U, the loop current is smaller, and at this time, the loop current is smaller than the switching current of the current sensing element 2; when the voltage Uc between the first control terminal 13 and the second control terminal 14 is smaller than 0.7U or larger than 1.3U, the loop current is larger, and at this time, the loop current is larger than or equal to the switching current of the current sensing element 2, and at this time, the coil of the ac contactor 1 is easily burned; where U is the rated voltage of the coil of the ac contactor 1, the rated voltage of the coil of the ac contactor 1 may be different according to the type of the ac contactor 1, and the rated voltage of the coil of the ac contactor is 220V.
The constant-frequency alternating current circuit provided by the embodiment of the invention comprises the alternating current contactor, the current sensitive element and the controller, and the controller can be integrated with the voltage fluctuation protection device of the constant-frequency alternating current circuit provided by the embodiment of the invention and can execute the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by the embodiment of the invention, so that the constant-frequency alternating current circuit can have the corresponding structure and characteristics for executing the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by the embodiment of the invention, and can achieve the beneficial effects of the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by the embodiment of the invention, and the same points can be described with reference to the following.
Example two
The embodiment of the invention provides a voltage fluctuation protection method of a fixed-frequency alternating current circuit, which can be used for preventing a loop current between a first control end and a second control end of an alternating current contactor from being burnt out due to unstable fixed-frequency alternating current power supply voltage. Fig. 4 is a flowchart of a voltage fluctuation protection method of a constant frequency ac circuit according to a second embodiment of the present invention, and referring to fig. 4, the protection method includes:
s110, acquiring a loop current signal between the first control end and the second control end based on the current sensing element.
The loop current signal between the first control terminal and the second control terminal may include a low current signal and a high current signal.
S120, determining the current working state of the alternating current contactor according to the loop current signal; the current operating state includes a normal operating state and an abnormal operating state.
When the current working state of the alternating current contactor is a normal working state, the alternating current contactor can control the on-off time of the alternating current contactor according to the change of the voltage between the first control end and the second control end; when the current working state of the alternating current contactor is an abnormal working state, the voltage between the first control end and the second control end of the alternating current contactor is changed, and the on-off time of the alternating current contactor cannot be controlled.
Specifically, in the working process of the fixed-frequency alternating current circuit, a loop current signal between the first control end and the second control end is obtained based on the current sensitive element, so that the current working state of the alternating current contactor is determined according to the loop current signal, for example, when the loop current signal is a high current signal, the current working state of the alternating current contactor can be determined to be an abnormal working state, and when the loop current signal is a low current signal, the current working state of the alternating current contactor can be determined to be a normal working state.
S130, controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor.
In an exemplary embodiment, when the current operating state of the ac contactor is a normal operating state, according to the current operating state of the ac contactor, the on-off time of the ac contactor may be controlled such that when the voltage between the first control terminal and the second control terminal of the ac contactor is large, for example, when the voltage between the first control terminal and the second control terminal is near the rated voltage of the coil of the ac contactor, the armature of the ac contactor may be attracted, so that the input terminal and the output terminal of the ac contactor are turned on, i.e., the ac contactor is in a turned-on state, and when the voltage between the first control terminal and the second control terminal of the ac contactor is small, for example, when the voltage between the first control terminal and the second control terminal is near 0V, the armature of the ac contactor may not be attracted, so that the input terminal and the output terminal of the ac contactor are turned on, i.e., the ac contactor is in a turned-off state; when the current working state of the alternating current contactor is an abnormal working state, the alternating current contactor is controlled to be in an off state no matter the voltage between the first control end and the second control end of the alternating current contactor is larger or smaller.
According to the embodiment, the loop current signal between the first control end and the second control end of the alternating-current contactor is obtained based on the current sensitive element, so that the current working state of the alternating-current contactor is determined according to the loop current signal, and the on-off time of the alternating-current contactor is controlled according to the current working state of the alternating-current contactor, so that when the loop current between the first control end and the second control end of the alternating-current contactor is overlarge due to unstable fixed-frequency alternating-current power supply voltage, the alternating-current contactor can be timely controlled to be disconnected, and the condition that the loop temperature between the first control end and the second control end of the alternating-current contactor is raised to burn the alternating-current contactor is prevented, so that the fixed-frequency alternating-current circuit cannot work normally is avoided; meanwhile, the first control end of the alternating current contactor is electrically connected with one end of the current sensing element through the second control end, the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply, loop current signals between the first control end and the second control end of the alternating current contactor are obtained based on the current sensing element, and the loop current signals between the first control end and the second control end can be obtained based on the current sensing element without complex wiring.
Example III
Fig. 5 is a flowchart of a voltage fluctuation protection method of a constant frequency ac circuit according to a third embodiment of the present invention. Based on the above embodiment, the present embodiment further increases how to determine the current working state of the ac contactor according to the loop current signal, and how to control the on-off time of the ac contactor according to the current working state of the ac contactor, and referring to fig. 5, the voltage fluctuation protection method specifically includes:
s210, acquiring a loop current signal between a first control end and a second control end based on the current sensing element.
S220, judging whether the loop current signal is smaller than a current threshold value; if yes, executing S230; if not, then S270 is performed.
The current threshold may be determined according to an attribute of the ac contactor coil, and illustratively, the loop current signal is a low current signal when the loop current signal is less than the current threshold, and is a high current signal when the loop current signal is greater than or equal to the current threshold. The larger the current threshold, the larger the acceptable voltage fluctuation range of the fixed frequency alternating current circuit, and when the voltage fluctuation range is larger, the higher the temperature of the coil of the alternating current contactor is, so that the burning is easier. In an exemplary embodiment, the current threshold may be a switching current of the current sensing element, when the loop current between the first control terminal and the second control terminal is smaller than the switching current, the resistance of the current sensing element is in a low resistance state, and when the loop current between the first control terminal and the second control terminal is greater than or equal to the switching current, the resistance of the current sensing element is instantaneously increased to present a high resistance state.
S230, determining that the current working state of the alternating current contactor is a normal working state.
S240, acquiring a power utilization signal of the alternating current power utilization load.
When the AC power load needs power, the power signal can be an enabling signal; when the alternating current power load does not need to use power, the power-using signal can be a non-enabling signal.
S250, when the power utilization signal of the alternating current power utilization load is an enabling signal, a first preset voltage is provided for the first control end, so that the alternating current contactor is in a conducting state.
The first preset voltage may be a rated operating voltage of a coil of the ac contactor. It can be understood that the first preset voltage provided to the first control terminal is a voltage provided to the first control terminal after the power grid is subjected to voltage conversion, so that the first preset voltage fluctuates with the fluctuation of the power grid voltage.
It can be understood that the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner, so that when the alternating current contactor is in a conducting state, each phase of the alternating current power utilization load is electrically connected with the fixed-frequency alternating current power supply through the alternating current contactor, and the fixed-frequency alternating current power supply supplies power to the alternating current power utilization load. Therefore, when the power utilization signal of the alternating current power utilization load is an enabling signal, the alternating current contactor can be in a conducting state by providing a first preset voltage to the first control end, so that each phase of the alternating current power utilization load is electrically connected with a fixed-frequency alternating current power supply through the alternating current contactor, and the fixed-frequency alternating current power supply supplies power to the alternating current power utilization load.
And S260, when the power utilization signal of the alternating current power utilization load is a non-enabling signal, providing a second preset voltage for the first control end so as to enable the alternating current contactor to be in an off state.
The second preset voltage may be a voltage smaller than a coil threshold voltage of the ac contactor, the coil threshold voltage of the ac contactor may be a voltage at which the electromagnetic attraction generated by the static iron core just can make the armature attracted after the coil of the ac contactor is electrified; in an exemplary embodiment, the second preset voltage may be 0V. When the power consumption signal of the alternating current power consumption load is a non-enabling signal, the alternating current contactor can be in an off state by providing a second preset voltage for the first control end, so that each phase of the alternating current power consumption load cannot be electrically connected with each phase of the fixed frequency alternating current power supply through the alternating current contactor, and the fixed frequency alternating current power supply cannot supply power for the alternating current power consumption load.
Specifically, in the working process of the fixed-frequency alternating current circuit, a loop current signal between the first control end and the second control end is obtained based on the current sensitive element, and when the loop current signal is smaller than a current threshold value, the current working state of the alternating current contactor is determined to be a normal working state. When the alternating-current contactor is in a normal working state, acquiring an electricity utilization signal of an alternating-current electricity utilization load, and when the electricity utilization signal of the alternating-current electricity utilization load is an enabling signal, providing a first preset voltage for a first control end to enable an armature of the alternating-current contactor to be attracted, so that the alternating-current contactor is in a conducting state, each phase of the alternating-current electricity utilization load is electrically connected with a fixed-frequency alternating-current power supply through the alternating-current contactor, and the fixed-frequency alternating-current power supply supplies power for the alternating-current electricity utilization load; when the power utilization signal of the alternating current power utilization load is a non-enabling signal, a second preset voltage is provided for the first control end, so that the alternating current contactor is in an off state, each phase of the alternating current power utilization load is electrically connected with each phase of the fixed frequency alternating current power supply through the alternating current contactor, and the fixed frequency alternating current power supply cannot supply power for the alternating current power utilization load.
S270, determining that the current working state of the alternating-current contactor is an abnormal working state.
And S280, providing a second preset voltage for the first control end so as to enable the alternating current contactor to be in an off state, and timing the current off time of the alternating current contactor.
Specifically, in the working process of the fixed-frequency alternating current circuit, a loop current signal between the first control end and the second control end is obtained based on the current sensitive element, and when the loop current signal is greater than or equal to a current threshold value, the current working state of the alternating current contactor is determined to be an abnormal working state. When the alternating current contactor is in an abnormal power supply state, a second preset voltage is provided for the first control end, so that the alternating current contactor is in an off state, the alternating current contactor is protected, and the coil temperature of the alternating current contactor is prevented from being burnt out due to overhigh temperature. It will be appreciated that the fluctuation of the grid voltage is affected by a number of factors, and therefore, at different times, the amount of fluctuation of the grid voltage is also different; therefore, when the voltage fluctuation of the power grid is large, loop current between a first control end and a second control end of the alternating-current contactor is large, so that the alternating-current contactor is in an abnormal working state, after the alternating-current contactor is in a disconnected state, the current disconnection time of the alternating-current contactor can be timed, and when the alternating-current contactor is in the disconnected state for a certain period of time, the working state of the alternating-current contactor can be restored, the loop current signal between the first control end and the second control end can be continuously acquired based on the current sensing element, and the working state of the alternating-current contactor can be determined.
And S290, when the current disconnection time of the alternating-current contactor reaches the preset time, providing a first preset voltage for enabling the alternating-current contactor to be in a conducting state to the first control end, and returning to execute S210.
The preset time can be determined empirically based on grid voltage fluctuations. If the preset time is too short, the alternating current contactor is likely to be frequently in an abnormal working state due to the fact that the voltage fluctuation of the power grid is still large, so that the alternating current power utilization load is frequently powered off, and if the preset time is too long, the alternating current power utilization load is powered off for a long time, and the normal power utilization requirement of the alternating current power utilization load is affected. In an exemplary embodiment, the preset time may be 3 minutes.
Specifically, when the alternating-current contactor is in an abnormal power supply state, the alternating-current contactor is in an off state by providing a second preset voltage to the first control end, and the current off time of the alternating-current contactor is timed; when the current disconnection time of the alternating-current contactor reaches the preset time, a first preset voltage which enables the alternating-current contactor to be in a conducting state is provided for the first control end, so that the fixed-frequency alternating-current circuit obtains a loop current signal between the first control end and the second control end again based on the current sensitive element, and the working state of the alternating-current contactor is determined.
In an alternative embodiment, if the power grid voltage fluctuates greatly for a long time, for example, if the ac contactor is still in an abnormal operating state after the ac contactor is continuously restored for a plurality of times within a certain period of time, the ac contactor is controlled to be turned off for a specific period of time, and then the operating state of the ac contactor is restored, wherein the specific period of time increases with the increase of the number of times of restoring the operating state of the ac contactor. For example, if the ac contactor is still in an abnormal working state after the working state of the ac contactor is recovered more than 3 times continuously within 30min, the ac contactor is controlled to be in an off state for 30min, and then the working state of the ac contactor is recovered; if the alternating current contactor is still in an abnormal working state for more than 3 times within 30min, controlling the alternating current contactor to be in an off state for 1h, and then recovering the working state of the alternating current contactor until the specific time reaches 4h.
In an alternative embodiment, after determining the current operating state of the ac contactor, the method further includes controlling a display device to display the current operating state of the ac contactor.
The display device may include, but is not limited to, various display screens with display functions, mobile phones, computers, and the like. In an exemplary embodiment, the display device may display not only the current operation state of the ac contactor, but also a corresponding fail-safe code or the like when the current operation state of the ac contactor is an abnormal operation state.
In this embodiment, when the loop current signal is smaller than the current threshold, the current working state of the ac contactor is determined to be a normal working state, and when the loop current signal is greater than or equal to the current threshold, the current working state of the ac contactor is determined to be an abnormal working state, so that when the voltage fluctuation is large, and the loop current between the first control end and the second control end is large, the ac contactor is controlled to be in an off state in time, and the coil temperature of the ac contactor is prevented from being high and being burnt. In addition, when the alternating-current contactor is in a normal working state, an electricity utilization signal of an alternating-current electricity utilization load is obtained, when the electricity utilization signal of the alternating-current electricity utilization load is an enabling signal, a first preset voltage is provided for a first control end, an armature of the alternating-current contactor is attracted, the alternating-current contactor is in a conducting state, each phase of the alternating-current electricity utilization load is electrically connected with a fixed-frequency alternating-current power supply through the alternating-current contactor, the fixed-frequency alternating-current power supply supplies power for the alternating-current electricity utilization load, when the electricity utilization signal of the alternating-current electricity utilization load is a non-enabling signal, a second preset voltage is provided for the first control end, the alternating-current contactor is in an off state, and therefore each phase of the alternating-current electricity utilization load is electrically connected with each phase of the fixed-frequency alternating-current power supply through the alternating-current contactor, and the fixed-frequency alternating-current power supply cannot supply power for the alternating-current electricity utilization load; when the alternating current contactor is in an abnormal power supply state, a second preset voltage is provided for the first control end, so that the alternating current contactor is in an off state, the alternating current contactor is protected, and the coil temperature of the alternating current contactor is prevented from being burnt out due to overhigh temperature. When the AC contactor is in an abnormal working state, the AC contactor is in an off state, and the current off time of the AC contactor is timed, so that when the current off time of the AC contactor reaches the preset time, the working state of the AC contactor is reset, the AC contactor can be in a normal working state when the voltage fluctuation of a power grid is small, the on-off time of the AC contactor can be controlled according to the power consumption signal of an AC power consumption load, and the AC contactor is protected while the fixed-frequency AC power supply can supply power to the AC power consumption load according to the power consumption signal of the AC power consumption load.
Example IV
The embodiment provides a voltage fluctuation protection device of a constant-frequency alternating current circuit, which can be realized in a hardware and/or software mode and can be integrated in a controller. Fig. 6 is a schematic structural diagram of a voltage fluctuation protection device for a constant frequency ac circuit according to a fifth embodiment of the present invention, as shown in fig. 6, the protection device includes:
the loop current signal acquisition module 310 is configured to acquire a loop current signal between the first control terminal and the second control terminal based on the current sensing element.
The working state determining module 320 is configured to determine a current working state of the ac contactor according to the loop current signal; the current operating state includes a normal operating state and an abnormal operating state.
The control module 330 is configured to control on-off time of the ac contactor according to a current operating state of the ac contactor.
The voltage fluctuation protection device of the constant-frequency alternating current circuit provided by the embodiment of the invention can execute the voltage fluctuation protection method of the constant-frequency alternating current circuit provided by any embodiment of the invention, has corresponding functional modules and beneficial effects of the execution method, and can be described with reference to the above.
Example six
Based on the same conception, the embodiments of the present invention also provide a computer readable storage medium storing computer instructions for causing a processor to implement the protection method provided in any of the above embodiments when executed.
In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain, or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, the computer readable storage medium may be a machine readable signal medium. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. The voltage fluctuation protection method of the constant-frequency alternating current circuit is characterized in that the constant-frequency alternating current circuit comprises an alternating current contactor and a current sensitive element; the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply; the voltage fluctuation protection method comprises the following steps:
acquiring a loop current signal between the first control end and the second control end based on the current sensing element;
determining the current working state of the alternating current contactor according to the loop current signal; the current working state comprises a normal working state and an abnormal working state;
and controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor.
2. The method of claim 1, wherein determining the current operating state of the ac contactor based on the loop current signal comprises:
judging whether the loop current signal is smaller than a current threshold value or not;
if yes, determining that the current working state of the alternating current contactor is a normal working state.
3. The method according to claim 2, wherein if the loop current signal is greater than or equal to the current threshold, determining that the current operating state of the ac contactor is an abnormal operating state.
4. The method according to claim 1, wherein controlling the on-off time of the ac contactor when the current operation state of the ac contactor is a normal operation state, comprises:
acquiring an electricity utilization signal of the alternating current electricity utilization load;
when the power utilization signal of the alternating current power utilization load is an enabling signal, a first preset voltage is provided for the first control end, so that the alternating current contactor is in a conducting state.
5. The method according to claim 4, wherein when the power signal of the ac power load is a disable signal, a second predetermined voltage is provided to the first control terminal to place the ac contactor in an open state.
6. The method according to claim 1, wherein controlling the on-off time of the ac contactor when the current operation state of the ac contactor is an abnormal operation state, comprises:
providing a second preset voltage for the first control end so as to enable the alternating current contactor to be in an off state, and timing the current off time of the alternating current contactor;
when the current disconnection time of the alternating current contactor reaches the preset time, a first preset voltage which enables the alternating current contactor to be in a conducting state is provided for the first control end, and loop current signals between the first control end and the second control end are acquired based on the current sensing element in a return mode.
7. The method of claim 1, further comprising, after determining the current operating state of the ac contactor:
and controlling a display device to display the current working state of the alternating current contactor.
8. The voltage fluctuation protection device of the constant-frequency alternating current circuit is characterized in that the constant-frequency alternating current circuit comprises an alternating current contactor and a current sensitive element; the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply; the voltage fluctuation protection device includes:
the loop current signal acquisition module is used for acquiring a loop current signal between the first control end and the second control end based on the current sensitive element;
the working state determining module is used for determining the current working state of the alternating current contactor according to the loop current signal; the current working state comprises a normal working state and an abnormal working state;
and the control module is used for controlling the on-off time of the alternating current contactor according to the current working state of the alternating current contactor.
9. A fixed frequency ac circuit comprising: an ac contactor, a current sensing element, and a controller;
the alternating current contactor comprises an input end, an output end, a first control end and a second control end; the input end is electrically connected with each phase of the fixed-frequency alternating current power supply in a one-to-one correspondence manner, and the output end is electrically connected with each phase of the alternating current power utilization load in a one-to-one correspondence manner; the first control end is electrically connected with one end of the current sensing element through the second control end, and the other end of the current sensing element is electrically connected with a zero line of the constant-frequency alternating current power supply;
the controller is configured to perform the voltage fluctuation protection method of the constant frequency alternating current circuit according to any one of claims 1 to 7.
10. A computer readable storage medium storing computer instructions for causing a processor to implement the method of protecting against voltage fluctuations of a fixed frequency ac circuit according to any of claims 1 to 7 when executed.
CN202310507614.8A 2023-05-06 2023-05-06 Fixed-frequency alternating current circuit, voltage fluctuation protection method and device thereof and storage medium Pending CN116505491A (en)

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