CN107919655B - Control circuit, control method and air conditioner - Google Patents
Control circuit, control method and air conditioner Download PDFInfo
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- CN107919655B CN107919655B CN201711326209.7A CN201711326209A CN107919655B CN 107919655 B CN107919655 B CN 107919655B CN 201711326209 A CN201711326209 A CN 201711326209A CN 107919655 B CN107919655 B CN 107919655B
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3277—Testing of circuit interrupters, switches or circuit-breakers of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
Abstract
The invention discloses a control circuit, a control method and an air conditioner, and relates to the technical field of electric equipment. The control circuit includes: the first relay group is arranged on a power grid fire wire connected with the rectifying module of the electric equipment and comprises a first relay and a second relay which are connected in series; a first controller for controlling a state of the first relay; a second controller for controlling a state of the second relay, the state including on or off; under the condition that one of the first relay and the second relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is used for determining that the relay which is controlled to be disconnected is abnormal in contact adhesion under the condition that the voltage of a first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value.
Description
Technical Field
The invention relates to the technical field of electric equipment, in particular to a control circuit, a control method and an air conditioner.
Background
Currently, the control circuit between the grid and the rectifying module 101 of the consumer comprises a relay 102 arranged on the line L connected to the rectifying module 101, and a controller 103 for controlling the state of the relay 102. The control circuit has a simple structure and a single function, but has potential safety hazards. For example, when an abnormality occurs in the power supply of the power grid, it is necessary to disconnect the electrical connection between the power grid and the rectification module 101.
However, the inventors found that if the relay 102 had abnormal contact adhesion, the electrical connection between the power grid and the rectifying module 101 could not be cut off, causing problems of sparking and electric shock.
Disclosure of Invention
The invention aims to solve the technical problems that: and the potential safety hazard problem caused by abnormal contact adhesion of the relay occurs.
According to an aspect of an embodiment of the present invention, there is provided a control circuit including: the first relay group is arranged on a power grid fire wire connected with the rectifying module of the electric equipment and comprises a first relay and a second relay which are connected in series; a first controller for controlling a state of the first relay; a second controller for controlling a state of the second relay, the state including on or off; under the condition that one of the first relay and the second relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is used for determining that the relay which is controlled to be disconnected is abnormal in contact adhesion under the condition that the voltage of a first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value.
In one embodiment, the first controller is further configured to instruct the second controller to control the second relay to open if it is determined that the first relay has abnormal contact adhesion when the first relay is controlled to open and the second relay is controlled to close.
In one embodiment, in the case that the first relay is determined to have abnormal contact adhesion, the second controller is further used for actively controlling the second relay to be disconnected in the case that the indication of the first controller is not received within a preset time.
In one embodiment, the first controller is further configured to control the first relay to open if it is determined that the second relay has abnormal contact adhesion in the case where the first relay is controlled to be closed and the second relay is controlled to be opened.
In one embodiment, the first controller is further configured to control the first relay to open and instruct the second controller to control the second relay to open if the second ac bus voltage between the first relay set and the power grid is less than a second threshold or greater than a third threshold, if the first relay and the second relay are controlled to be engaged; wherein the second threshold is less than the third threshold.
In one embodiment, the control circuit further comprises: the branch circuits are connected with two ends of the first relay group in a bridging way, and a fifth relay and a resistor which are connected in series are arranged on the branch circuits; the first controller is also used for controlling the fifth relay to be attracted under the condition that the first relay and the second relay are disconnected so as to charge the direct current bus capacitor; the first controller is also used for controlling the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value and indicating the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
According to another aspect of an embodiment of the present invention, there is provided a control circuit including: the first relay group is arranged on a power grid fire wire connected with the rectifying module of the electric equipment and comprises a first relay and a second relay which are connected in series; the second relay group is arranged on a power grid zero line of the rectifying module and comprises a third relay and a fourth relay which are connected in series; a first controller for controlling states of the first relay and the third relay; and a second controller for controlling states of the second relay and the fourth relay, the states including on or off; under the condition that one of the first relay, the second relay, the third relay and the fourth relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is used for determining that the relay which is controlled to be disconnected is abnormal in contact adhesion under the condition that the voltage of a first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value.
In one embodiment, in a case that one of the first relay and the second relay is controlled to be opened and the other is controlled to be closed, the first controller is further configured to control the opening of the relay controlled to be closed in the first relay and the second relay and instruct the second controller to control the opening of the third relay and the fourth relay in a case that it is determined that the relay controlled to be opened has abnormal contact adhesion.
In one embodiment, in the case that it is determined that the relay controlled to be opened has abnormal contact adhesion, the second controller is further configured to actively control the third relay to be opened with the fourth relay in the case that the instruction of the first controller is not received within a preset time.
In one embodiment, in the case that one of the third relay and the fourth relay is controlled to be opened and the other is controlled to be closed, the first controller is further configured to control the first relay and the second relay to be opened and instruct the second controller to control the relay controlled to be closed to be opened in the third relay and the fourth relay in the case that it is determined that the relay controlled to be opened has abnormal contact adhesion.
In one embodiment, the first controller is further configured to control the first relay and the second relay to open and instruct the second controller to control the third relay and the fourth relay to open if a second ac bus voltage between the first relay set and the power grid is less than a second threshold or greater than a third threshold, where the first relay, the second relay, the third relay, and the fourth relay are controlled to be energized; wherein the second threshold is less than the third threshold.
In one embodiment, the control circuit further comprises: the branch circuits are connected with two ends of the first relay group in a bridging way, and a fifth relay and a resistor which are connected in series are arranged on the branch circuits; the first controller is also used for controlling the third relay to be closed under the condition that all relays are opened, and indicating the second controller to control the fourth relay to be closed; after the fourth relay is attracted, controlling the fifth relay to attract so as to charge the direct current bus capacitor; the first controller is also used for controlling the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value and indicating the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
According to still another aspect of an embodiment of the present invention, there is provided an air conditioner including: the control circuit of any one of the embodiments above.
According to still another aspect of the embodiments of the present invention, there is provided a control method based on the control circuit described in any one of the above embodiments, including: one of the first relay and the second relay is controlled to be disconnected and the other is controlled to be connected; and under the condition that the voltage of the first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value, determining that the relay which is controlled to be disconnected is abnormal in contact adhesion.
In one embodiment, the controlling of one of the first relay and the second relay to open and the other to close includes: the first relay is controlled to be disconnected and the second relay is controlled to be closed; the method further comprises the steps of: and under the condition that the first relay is determined to have abnormal contact adhesion, the first controller instructs the second controller to control the second relay to be opened.
In one embodiment, the method further comprises: and under the condition that the first relay is determined to have abnormal contact adhesion, the second controller actively controls the second relay to be disconnected under the condition that the second controller does not receive the indication of the first controller within the preset time.
In one embodiment, the controlling of one of the first relay and the second relay to open and the other to close includes: controlling the first relay to be closed and the second relay to be opened; the method further comprises the steps of: and under the condition that the contact adhesion abnormality of the second relay is determined, the first controller controls the first relay to be disconnected.
In one embodiment, the method further comprises: controlling the first relay and the second relay to be attracted; when the voltage of a second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay to be disconnected, and the second controller is instructed to control the second relay to be disconnected; wherein the second threshold is less than the third threshold.
In one embodiment, the method further comprises: the first controller controls the fifth relay to be attracted under the condition that the first relay and the second relay are disconnected so as to charge the direct-current bus capacitor; the first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted; and the first controller controls the fifth relay to be disconnected after the second relay is attracted.
According to still another aspect of the embodiments of the present invention, there is provided a control method based on the control circuit described in any one of the above embodiments, including: one of the first relay, the second relay, the third relay and the fourth relay is controlled to be disconnected and the other relays are controlled to be connected; and under the condition that the voltage of the first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value, determining that the relay which is controlled to be disconnected is abnormal in contact adhesion.
In one embodiment, the controlling of the opening and the closing of one of the first relay, the second relay, the third relay, and the fourth relay includes: controlling one of the first relay and the second relay to be disconnected and the other to be connected, and controlling the third relay and the fourth relay to be connected; the method further comprises the steps of: and under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the relay controlled to be closed in the first relay and the second relay to be opened, and instructs the second controller to control the third relay and the fourth relay to be opened.
In one embodiment, the method further comprises: and under the condition that the relay which is controlled to be disconnected is determined to have abnormal contact adhesion, the second controller actively controls the third relay and the fourth relay to be disconnected under the condition that the second controller does not receive the indication of the first controller within the preset time.
In one embodiment, the controlling of the opening and the closing of one of the first relay, the second relay, the third relay, and the fourth relay includes: controlling the first relay and the second relay to be in attraction, and controlling one of the third relay and the fourth relay to be disconnected and the other relay to be in attraction; the method further comprises the steps of: under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the first relay to be opened with the second relay and instructs the second controller to control the relay controlled to be closed with the third relay to be opened with the fourth relay.
In one embodiment, the method further comprises: controlling the first relay, the second relay, the third relay and the fourth relay to be in attraction; when the voltage of a second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay and the second relay to be disconnected, and the second controller is instructed to control the third relay and the fourth relay to be disconnected; wherein the second threshold is less than the third threshold.
In one embodiment, the method further comprises: the first controller controls the third relay to be closed under the condition that all relays are opened, and instructs the second controller to control the fourth relay to be closed; after the fourth relay is attracted, controlling the fifth relay to attract so as to charge the direct current bus capacitor; the first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
In the control circuit provided by the embodiment of the invention, two relays connected in series are arranged on a power grid fire wire, and two controllers are arranged and respectively control the state of one relay. In this way, if the first ac bus voltage is greater than the first threshold value under the condition that one relay is opened and the other relay is closed, it can be determined that the relay controlled to be opened has abnormal contact adhesion. And the contact adhesion abnormality of the relay is determined to be favorable for improving the operation safety of electric equipment.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a prior art control circuit;
FIG. 2 is a schematic diagram of a control circuit according to one embodiment of the invention;
FIG. 3 is a schematic diagram of a control circuit according to another embodiment of the present invention;
fig. 4 is a schematic diagram of a control circuit according to yet another embodiment of the present invention;
fig. 5 is a schematic diagram of a control circuit according to still another embodiment of the present invention;
FIG. 6 is a flow chart of a control method according to one embodiment of the invention;
fig. 7 is a flow chart of a control method according to another embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
Fig. 2 is a schematic diagram of a control circuit according to an embodiment of the present invention. The control circuit may be disposed between the power grid and the rectification module 204 of the powered device. The powered device may be, for example, an air conditioner, which may include, but is not limited to, a photovoltaic air conditioner. However, the present invention is not limited thereto, and the electric device may be other electric devices or the like. Here, the rectifying module 204 may convert the ac power of the power grid into dc power; alternatively, in the case that the electric device is a photovoltaic air conditioner, the rectifying module 204 may also convert dc power into ac power for grid connection. As one example, the rectification module 204 may be implemented with an Intelligent Power Module (IPM).
As shown in fig. 2, the control circuit includes a first relay group 201, a first controller 202, and a second controller 203.
The first relay group 201 is arranged on a power grid live line L connected to a rectifying module 204 of the electric equipment. For example, the first relay set 201 may be connected to an Intelligent Power Module (IPM) of the powered device 204. The first relay group 201 may include at least a first relay 211 and a second relay 221 connected in series. It should be appreciated that the first relay group 201 may also include more relays in series with the first relay 211 and the second relay 221.
The first controller 202 is configured to control the state of the first relay 211, i.e., on or off. The second controller 203 is used to control the state of the second relay 221. For example, the first controller 202 and the first relay 211 may be commonly connected to a node 205 on the grid line L, and the second controller 203 and the second relay 221 may be commonly connected to a node 206 on the grid line L.
Illustratively, the first controller 202 and the second controller 203 may include Digital Signal Processors (DSPs) that may interact with information via IO interfaces (e.g., interface X1, interface X2, interface X3, or interface X4).
In the case where one of the first relay 211 and the second relay 221 is controlled to be turned off and the other is controlled to be turned on, the first controller 202 is configured to determine that the relay controlled to be turned off is abnormal in contact adhesion in the case where the first ac bus voltage V1 (i.e., the potential difference between the node 206 and the neutral line N) between the first relay group 201 and the rectifying module 204 is greater than a first threshold value. Here, V1 may be acquired by only the first controller 202, or may be acquired by both the first controller 202 and the first controller 203. In addition, the first threshold value may be a preset empirical value, for example, may be half of the rated voltage of the grid power supply.
In the control circuit of the above embodiment, two relays connected in series are provided on the grid fire line, and two controllers are provided, each of which controls the state of one relay. In this way, if the first ac bus voltage is greater than the first threshold value under the condition that one relay is opened and the other relay is closed, it can be determined that the relay controlled to be opened has abnormal contact adhesion. And the contact adhesion abnormality of the relay is determined to be favorable for improving the operation safety of electric equipment.
In practical application, whether contact adhesion abnormality occurs in each relay can be detected according to a preset period when electric equipment does not operate. For example, the first controller 202 may control the first relay 211 to open and instruct the second controller 203 to control the second relay to close, so that it may be detected whether the first relay 211 has abnormal contact adhesion; for another example, the first controller 202 may control the first relay 211 to be engaged and instruct the second controller 203 to control the second relay 221 to be opened, so that whether the second relay 221 has abnormal contact adhesion may be detected.
After determining that the first relay 211 or the second relay 221 has abnormal contact adhesion, a subsequent operation may be performed. For example, an alarm may be given to alert an associated person to break the electrical connection between the power grid and the rectifier module 204; alternatively, the electrical connection between the grid and the rectifier module 204 may be actively cut off. Here, the electrical connection between the power grid and the rectifying module 204 is cut off, i.e. the electrical connection between the power grid and the consumer is cut off.
In one implementation, the first relay 211 is controlled to open and the second relay 221 is controlled to close. In the case that it is determined that the first relay 211 has abnormal contact adhesion, the first controller 202 may be used to instruct the second controller 203 to control the second relay 221 to be disconnected, so as to cut off the electrical connection between the power grid and the rectifying module 204, form an island, and improve the safety of the electric equipment during operation.
In some cases, the first controller 202 may not be able to instruct the second controller 203 to control the second relay 221 to be turned off. In one embodiment, in order to ensure that the electrical connection between the power grid and the rectifying module 204 is cut off in time, the operation safety of the electric equipment is further improved, and in the case that it is determined that the first relay 211 is abnormal in contact adhesion, the second controller 203 may be further configured to actively control the second relay 221 to be disconnected in the case that the instruction of the first controller is not received in a preset time, so as to further improve the operation safety of the electric equipment.
In another implementation, the first relay 211 is controlled to be on and the second relay 221 is controlled to be off. In this case, the first controller 202 may be configured to control the first relay 211 to be opened to cut off the electrical connection between the power grid and the rectification module 204 in the case where it is determined that the contact adhesion abnormality occurs in the second relay 221.
When the electric equipment works, if the power supply voltage of the power grid is detected to be abnormal, the electric connection between the power grid and the electric equipment can be cut off, so that the operation safety of the electric equipment is further improved. In one embodiment, where the first relay 211 and the second relay 221 are controlled to be on, the first controller 202 may also be configured to control the first relay 211 to be off and instruct the second controller 203 to control the second relay 221 to be off if the second ac busbar voltage V2 between the first relay group 201 and the power grid (i.e., the potential difference between the node 205 and the neutral line) is less than a second threshold or greater than a third threshold. Here, the second threshold value is smaller than the third threshold value, both of which may be set according to actual conditions.
Fig. 3 is a schematic diagram of a control circuit according to another embodiment of the present invention.
In comparison with the embodiment shown in fig. 2, the control circuit of the embodiment shown in fig. 3 further comprises a branch connected across the first relay group 201, on which a fifth relay 251 and a resistor R are arranged, which are connected in series.
The control circuit of this embodiment may be used for soft start charging control for charging the dc bus capacitor to reduce the overcurrent impact on the dc bus capacitor, as described in detail below.
The first controller 202 may control the fifth relay 251 to be turned on in order to charge the dc bus capacitor in the case where the first relay 211 and the second relay 221 are turned off. After a preset period of time (for example, after 2 s), the first controller 202 may control the first relay 211 to be turned on and instruct the second controller 203 to control the second relay 221 to be turned on when the dc bus voltage is greater than a fourth threshold (for example, 215V may be used); after the second relay 221 is engaged, the fifth relay 251 is controlled to be turned off, thereby completing the normal soft start charging control.
Alternatively, after the second relay 221 is engaged, a time delay may be provided, for example, after 2 seconds, to control the fifth relay 251 to be turned off.
In addition, if the dc bus voltage is not greater than the fourth threshold value, which is detected for a predetermined number of times, the first controller 202 may control the first relay 211 to be turned off and instruct the second controller 203 to control the second relay 221 to be turned off.
It should be appreciated that although a dc bus capacitor is not shown in fig. 3, those skilled in the art will appreciate that the rectifier module 204 may flow to the dc bus capacitor after converting the ac power of the power grid to dc power. This is described herein too much.
Fig. 4 is a schematic diagram of a control circuit according to still another embodiment of the present invention. Only the differences between the embodiment of fig. 4 and the embodiment of fig. 2 will be described with reference to the above description.
In comparison with the embodiment shown in fig. 2, the embodiment shown in fig. 4 further comprises a second relay set 401 arranged on the neutral line N of the power network of the rectifying module 204 connected to the consumer.
The second relay group 401 may include at least a third relay 231 and a fourth relay 241 connected in series. It should be appreciated that the second relay set 401 may also include more relays in series with the third relay 231 and the fourth relay 241.
In this embodiment, the first controller 202 is used to control the states of the first relay 211 and the third relay 231. The second controller 203 is used to control the states of the third relay 231 and the fourth relay 241.
In the case where one of the first relay 211, the second relay 221, the third relay 231, and the fourth relay 241 is controlled to be turned off, and the other is controlled to be turned on, the first controller 202 is configured to determine that the relay controlled to be turned off has abnormal contact adhesion in the case where the first ac bus voltage V1 between the first relay group 201 and the rectifying module 204 is greater than the first threshold value.
Table 1 shows a signal diagram of the interaction between the first controller 202 and the second controller 203 when detecting whether or not contact adhesion abnormality occurs in each relay.
TABLE 1
The following description will be given by taking an example of detecting whether the first relay 211 is stuck or not, and other relays are similar.
The first controller 202 controls the first relay 211 to be opened and controls the third relay 231 to be closed. For example, the first controller 202 may transmit a signal 0 indicating the state of the first relay 211 through the interface X1 and a signal 1 indicating the state of the third relay 231 through the interface X2.
The second controller 203, upon receiving the signal 0 and the signal 1, controls the second relay 221 and the fourth relay 241 to be actuated. After a period of time (e.g., 20 ms), a signal 0 is sent to the first controller 202 through the interface X3, and a signal 1 is sent to the first controller 202 through the interface X4 to inform the second controller 203 that the second relay 221 and the fourth relay 241 have been controlled to complete the actuation.
In the control circuit of the above embodiment, two relays connected in series are provided on the grid fire line, and two relays connected in series are also provided on the grid zero line. The embodiment can detect whether any relay has abnormal contact adhesion.
In one implementation, in a case where one of the first relay 211 and the third relay 231 is controlled to be opened and the other is controlled to be closed, the first controller 202 is further configured to control the opening of the relay controlled to be closed in the first relay 211 and the third relay 231 and instruct the second controller 203 to control the opening of the second relay 221 and the fourth relay 241 to cut off the electrical connection between the power grid and the rectifying module 204, so as to improve the operation safety of the electric equipment. Optionally, in the case that it is determined that the contact adhesion of the relay controlled to be opened is abnormal, the second controller 203 is further configured to actively control the second relay 221 and the fourth relay 241 to be opened when no indication of the first controller 202 is received within a preset time, so as to further improve the operation safety of the electric equipment.
In another implementation manner, in a case where one of the second relay 221 and the fourth relay 241 is controlled to be opened and the other is controlled to be closed, the first controller 202 is further configured to control the first relay 211 and the third relay 231 to be opened and instruct the second controller 203 to control the opening of the relay controlled to be closed in the second relay 221 and the fourth relay 241, so as to cut off the electrical connection between the power grid and the rectifying module 204, and improve the operation safety of the electric equipment.
In one embodiment, in the case where the first relay 211, the second relay 221, the third relay 231, and the fourth relay 241 are controlled to be engaged, the first control 202 is further configured to control the first relay 211 and the third relay 231 to be turned off, and instruct the second controller 203 to control the second relay 221 and the fourth relay 241 to be turned off, in the case where the second ac bus voltage V2 between the first relay group 201 and the power grid is less than the second threshold or greater than the third threshold; wherein the second threshold is less than the third threshold.
Fig. 5 is a schematic diagram of a control circuit according to still another embodiment of the present invention. Only the differences between the embodiment of fig. 5 and fig. 4 will be described with reference to the above description.
In comparison with the embodiment shown in fig. 4, the embodiment shown in fig. 5 further comprises a branch connected across the first relay group 201, on which a fifth relay 251 and a resistor R are arranged, which are connected in series.
The first controller 202 is further configured to control the third relay 231 to be actuated when all relays are opened, and instruct the second controller 203 to control the fourth relay 241 to be actuated; after the fourth relay 241 is turned on, the fifth relay 251 is controlled to be turned on so as to charge the dc bus capacitor connected to the rectifier module 204.
The first controller 202 is further configured to control the first relay 211 to be actuated when the dc bus voltage is greater than the fourth threshold, and instruct the second controller 203 to control the second relay 221 to be actuated; after the second relay 221 is engaged, the fifth relay 251 is controlled to be turned off.
Similarly, if the dc bus voltage is detected not to be greater than the fourth threshold value for all of the consecutive preset times, the first controller 202 may control the first relay 211 and the third relay 231 to be turned off and instruct the second controller 203 to control the second relay 221 and the fourth relay 241 to be turned off, indicating that the charging circuit may be faulty.
The invention also provides an air conditioner, comprising: the control circuit of any of the above embodiments. In one embodiment, the air conditioner may include, but is not limited to, a photovoltaic air conditioner, such as a photovoltaic inverter air conditioner.
When grid-connected faults of the photovoltaic air conditioner are detected, for example, leakage current between the photovoltaic panel and the ground exceeds a preset value and the like, the control circuit controls the relays to be disconnected to avoid safety problems caused by grid connection.
The invention also provides a control method of the control circuit based on the embodiment.
Fig. 6 is a flow chart of a control method according to an embodiment of the present invention.
In step 602, one of the first relay and the second relay is controlled to be opened and the other is controlled to be closed.
For example, the first relay is controlled to be opened and the second relay is controlled to be closed; for another example, the first relay is controlled to be opened and the second relay is controlled to be closed.
In step 604, in a case where the first ac bus voltage between the first relay group and the rectifying module is greater than a first threshold value, it is determined that the relay controlled to be turned off has abnormal contact adhesion.
In the case of determining that the first relay has abnormal contact adhesion, the first controller may instruct the second controller to control the second relay to open. In addition, the first controller may control the first relay to open in the case where it is determined that the contact adhesion abnormality occurs in the second relay.
Optionally, under the condition that the first relay is determined to have abnormal contact adhesion, the second controller actively controls the second relay to be disconnected under the condition that the second controller does not receive the indication of the first controller within a preset time.
In the above embodiment, in the case where one relay is opened and the other relay is closed, if the first ac bus voltage is greater than the first threshold value, it may be determined that the relay controlled to be opened has abnormal contact adhesion.
In one embodiment, to further improve the operation safety of the electric device, the method shown in fig. 6 may further include: controlling the first relay and the second relay to be attracted; when the voltage of the second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay to be disconnected, and the second controller is instructed to control the second relay to be disconnected; wherein the second threshold is less than the third threshold.
In the above embodiment, when the voltage of the second ac bus is smaller than the second threshold or greater than the third threshold, it may be determined that the power supply of the power grid is abnormal, and the electrical connection between the power grid and the electric device may be cut off by controlling the first relay and the second relay to be disconnected.
In one embodiment, the method shown in fig. 6 may further include: the first controller controls the fifth relay to be attracted under the condition that the first relay and the second relay are disconnected so as to charge the direct-current bus capacitor; the first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted; and the first controller controls the fifth relay to be disconnected after the second relay is attracted. The embodiment can avoid overcurrent impact on the direct current bus capacitor through soft start control.
Fig. 7 is a flow chart of a control method according to another embodiment of the present invention.
In step 702, one of the first relay, the second relay, the third relay, and the fourth relay is controlled to be turned off and the other is controlled to be turned on.
For example, one of the first relay and the second relay is controlled to be turned off, the other is controlled to be turned on, and the third relay and the fourth relay are controlled to be turned on; for another example, the first relay and the second relay are controlled to be actuated, and one of the third relay and the fourth relay is controlled to be opened and the other to be actuated.
In step 704, in a case where the first ac bus voltage between the first relay group and the rectifying module is greater than a first threshold value, it is determined that the relay controlled to be turned off has abnormal contact adhesion.
For example, one of the first relay and the third relay is controlled to be turned off, the other is controlled to be turned on, and the second relay and the fourth relay are controlled to be turned on. And under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the relay controlled to be closed in the first relay and the third relay to be opened, and instructs the second controller to control the second relay and the fourth relay to be opened. Optionally, under the condition that the relay controlled to be opened is determined to have abnormal contact adhesion, the second controller actively controls the second relay and the fourth relay to be opened under the condition that the second controller does not receive the indication of the first controller within a preset time.
For another example, the first relay and the third relay are controlled to be actuated, and one of the second relay and the fourth relay is controlled to be opened and the other to be actuated. Under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the first relay and the third relay to be opened, and the second controller is instructed to control the relay controlled to be closed in the second relay and the fourth relay to be opened.
In one embodiment, to further improve the operation safety of the electric device, the method shown in fig. 7 may further include: controlling the first relay, the second relay, the third relay and the fourth relay to be in attraction; when the voltage of the second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay and the third relay to be disconnected, and the second controller is instructed to control the second relay and the fourth relay to be disconnected; wherein the second threshold is less than the third threshold.
In one embodiment, the method shown in fig. 7 may further include: the first controller controls the third relay to be closed under the condition that all relays are opened, and instructs the second controller to control the fourth relay to be closed; after the fourth relay is attracted, controlling the fifth relay to attract so as to charge the direct current bus capacitor; the first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened. The embodiment can avoid overcurrent impact on the direct current bus capacitor through soft start control.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, so that the same or similar parts between the embodiments are mutually referred to. For the control method embodiments, since they basically correspond to the control circuit embodiments, the description is relatively simple, and the relevant points are only referred to in the description of the method embodiments.
Thus, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concepts of the invention, some details known in the art have not been described. How to implement the solutions disclosed herein will be fully apparent to those skilled in the art from the above description.
The method and circuit of the invention may be implemented in many ways. For example, the methods and apparatus of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, firmware. The above-described sequence of steps for the method is for illustration only, and the steps of the method of the present invention are not limited to the sequence specifically described above unless specifically stated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.
While certain specific embodiments of the invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (21)
1. A control circuit, comprising:
the first relay group is arranged on a power grid fire wire connected with the rectifying module of the electric equipment and comprises a first relay and a second relay which are connected in series;
a first controller for controlling a state of the first relay;
a second controller for controlling a state of the second relay, the state including on or off;
under the condition that one of the first relay and the second relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is used for determining that the relay which is controlled to be disconnected is abnormal in contact adhesion under the condition that the first alternating current bus voltage between the first relay group and the rectifying module is larger than a first threshold value;
The first controller is also used for indicating the second controller to control the second relay to be disconnected under the condition that the contact adhesion abnormality of the first relay is determined under the condition that the first relay is controlled to be disconnected and the second relay is controlled to be attracted;
and under the condition that the first relay is determined to have abnormal contact adhesion, the second controller is also used for actively controlling the second relay to be disconnected under the condition that the indication of the first controller is not received within the preset time.
2. The control circuit of claim 1, wherein,
under the condition that the first relay is controlled to be attracted and the second relay is controlled to be disconnected, the first controller is further used for controlling the first relay to be disconnected under the condition that the contact adhesion abnormality of the second relay is determined.
3. Control circuit according to any of the claims 1-2, characterized in that,
the first controller is further used for controlling the first relay to be disconnected and instructing the second controller to control the second relay to be disconnected when the voltage of the second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value under the condition that the first relay and the second relay are controlled to be attracted; wherein the second threshold is less than the third threshold.
4. The control circuit of claim 1, further comprising:
the branch circuits are connected with two ends of the first relay group in a bridging way, and a fifth relay and a resistor which are connected in series are arranged on the branch circuits;
the first controller is also used for controlling the fifth relay to be attracted under the condition that the first relay and the second relay are disconnected so as to charge the direct current bus capacitor;
the first controller is also used for controlling the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value and indicating the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
5. A control circuit, comprising:
the first relay group is arranged on a power grid fire wire connected with the rectifying module of the electric equipment and comprises a first relay and a second relay which are connected in series;
the second relay group is arranged on a power grid zero line connected with the rectifying module and comprises a third relay and a fourth relay which are connected in series;
a first controller for controlling states of the first relay and the third relay; and
A second controller for controlling states of the second relay and the fourth relay, the states including on or off;
under the condition that one of the first relay, the second relay, the third relay and the fourth relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is used for determining that the relay which is controlled to be disconnected is abnormal in contact adhesion under the condition that the first alternating current bus voltage between the first relay group and the rectifying module is larger than a first threshold value;
the first controller is also used for controlling the relay which is controlled to be attracted to be disconnected in the first relay and the third relay and indicating the second controller to control the second relay and the fourth relay to be disconnected under the condition that the relay which is controlled to be disconnected is determined to have abnormal contact adhesion;
and under the condition that the relay which is controlled to be opened is determined to have abnormal contact adhesion, the second controller is also used for actively controlling the second relay and the fourth relay to be opened under the condition that the indication of the first controller is not received within the preset time.
6. The control circuit of claim 5, wherein the control circuit comprises a logic circuit,
and under the condition that one of the second relay and the fourth relay is controlled to be disconnected and the other relay is controlled to be attracted, the first controller is further used for controlling the first relay and the third relay to be disconnected under the condition that the relay controlled to be disconnected is determined to have abnormal contact adhesion, and the second controller is instructed to control the relay controlled to be attracted to be disconnected.
7. Control circuit according to any of the claims 5-6, characterized in that,
the first controller is further configured to control the first relay and the third relay to be turned off and instruct the second controller to control the second relay and the fourth relay to be turned off when the voltage of the second ac bus between the first relay group and the power grid is less than a second threshold or greater than a third threshold, in the case where the first relay, the second relay, the third relay, and the fourth relay are controlled to be turned on; wherein the second threshold is less than the third threshold.
8. The control circuit of claim 5, further comprising:
the branch circuits are connected with two ends of the first relay group in a bridging way, and a fifth relay and a resistor which are connected in series are arranged on the branch circuits;
The first controller is also used for controlling the third relay to be closed under the condition that all relays are opened, and indicating the second controller to control the fourth relay to be closed; after the fourth relay is attracted, controlling the fifth relay to attract so as to charge the direct current bus capacitor;
the first controller is also used for controlling the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value and indicating the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
9. An air conditioner, comprising: the control circuit of any one of claims 1-8.
10. A control method based on the control circuit according to any one of claims 1 to 4, characterized by comprising:
one of the first relay and the second relay is controlled to be disconnected and the other is controlled to be connected;
and under the condition that the voltage of the first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value, determining that the relay which is controlled to be disconnected is abnormal in contact adhesion.
11. The control method according to claim 10, wherein the controlling of one of the first relay and the second relay to be turned off and the other to be turned on includes:
The first relay is controlled to be disconnected and the second relay is controlled to be closed;
the method further comprises the steps of:
and under the condition that the first relay is determined to have abnormal contact adhesion, the first controller instructs the second controller to control the second relay to be opened.
12. The control method according to claim 11, characterized by further comprising:
and under the condition that the first relay is determined to have abnormal contact adhesion, the second controller actively controls the second relay to be disconnected under the condition that the second controller does not receive the indication of the first controller within the preset time.
13. The control method according to claim 10, wherein the controlling of one of the first relay and the second relay to be turned off and the other to be turned on includes:
controlling the first relay to be closed and the second relay to be opened;
and under the condition that the contact adhesion abnormality of the second relay is determined, the first controller controls the first relay to be disconnected.
14. The control method according to any one of claims 10 to 13, characterized by further comprising:
controlling the first relay and the second relay to be attracted;
when the voltage of a second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay to be disconnected, and the second controller is instructed to control the second relay to be disconnected; wherein the second threshold is less than the third threshold.
15. The control method according to claim 10, characterized by further comprising:
the first controller controls the fifth relay to be attracted under the condition that the first relay and the second relay are disconnected so as to charge the direct-current bus capacitor;
the first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted;
and the first controller controls the fifth relay to be disconnected after the second relay is attracted.
16. A control method based on the control circuit according to any one of claims 5 to 8, characterized by comprising:
one of the first relay, the second relay, the third relay and the fourth relay is controlled to be disconnected and the other relays are controlled to be connected;
and under the condition that the voltage of the first alternating current bus between the first relay group and the rectifying module is larger than a first threshold value, determining that the relay which is controlled to be disconnected is abnormal in contact adhesion.
17. The control method according to claim 16, wherein the controlling of one of the first relay, the second relay, the third relay, and the fourth relay to be turned off, and the other to be turned on includes:
Controlling one of the first relay and the third relay to be disconnected and the other to be connected, and controlling the second relay and the fourth relay to be connected;
the method further comprises the steps of:
and under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the relay controlled to be closed in the first relay and the third relay to be opened, and instructs the second controller to control the second relay and the fourth relay to be opened.
18. The control method according to claim 17, characterized by further comprising:
and under the condition that the relay which is controlled to be disconnected is determined to have abnormal contact adhesion, the second controller actively controls the second relay to be disconnected with the fourth relay under the condition that the second controller does not receive the indication of the first controller within the preset time.
19. The control method according to claim 16, wherein the controlling of one of the first relay, the second relay, the third relay, and the fourth relay to be turned off, and the other to be turned on includes:
controlling the first relay and the third relay to be in attraction, and controlling one of the second relay and the fourth relay to be disconnected and the other relay to be in attraction;
the method further comprises the steps of:
Under the condition that the relay controlled to be opened is abnormal in contact adhesion, the first controller controls the first relay and the third relay to be opened, and the second controller is instructed to control the relay controlled to be closed in the second relay and the fourth relay to be opened.
20. Control method according to any one of claims 16-19, characterized in that,
controlling the first relay, the second relay, the third relay and the fourth relay to be in attraction;
when the voltage of a second alternating current bus between the first relay group and the power grid is smaller than a second threshold value or larger than a third threshold value, the first controller controls the first relay and the third relay to be disconnected, and the second controller is instructed to control the second relay and the fourth relay to be disconnected; wherein the second threshold is less than the third threshold.
21. The control method according to claim 16, characterized by further comprising:
the first controller controls the third relay to be closed under the condition that all relays are opened, and instructs the second controller to control the fourth relay to be closed; after the fourth relay is attracted, controlling the fifth relay to attract so as to charge the direct current bus capacitor;
The first controller controls the first relay to be attracted under the condition that the voltage of the direct current bus is larger than a fourth threshold value, and instructs the second controller to control the second relay to be attracted; and after the second relay is attracted, the fifth relay is controlled to be opened.
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| CN201711326209.7A CN107919655B (en) | 2017-12-13 | 2017-12-13 | Control circuit, control method and air conditioner |
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| CN201711326209.7A CN107919655B (en) | 2017-12-13 | 2017-12-13 | Control circuit, control method and air conditioner |
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| CN109103979B (en) * | 2018-10-24 | 2023-11-10 | 珠海格力电器股份有限公司 | Photovoltaic electric equipment, charging control method and device thereof, circuit and storage medium |
| CN112393379A (en) * | 2020-11-19 | 2021-02-23 | 珠海格力电器股份有限公司 | Compressor driving circuit, power-off protection method thereof and air conditioner |
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