CN109545620B - Protective circuit and method of relay - Google Patents
Protective circuit and method of relay Download PDFInfo
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- CN109545620B CN109545620B CN201811326436.4A CN201811326436A CN109545620B CN 109545620 B CN109545620 B CN 109545620B CN 201811326436 A CN201811326436 A CN 201811326436A CN 109545620 B CN109545620 B CN 109545620B
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- relay
- triode
- resistor
- control module
- turn
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/002—Monitoring or fail-safe circuits
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/02—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for modifying the operation of the relay
- H01H47/18—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for modifying the operation of the relay for introducing delay in the operation of the relay
Abstract
The embodiment of the invention discloses a protection circuit and a protection method of a relay, relates to the field of frequency converters, and solves the problem that a contact of an onboard relay is burnt when a compressor or a motor runs. The specific scheme is as follows: the protection circuit of the relay comprises a processor, a switch module and a control module; the first end of the processor is connected with the first end of the switch module, the second end of the switch module is connected with the first end of the control module, and the second end of the control module is used for being connected with the relay; the second end of the processor is used for connecting the power device; the control module is used for controlling the relay to be switched off when the switch module is switched off; the processor is used for detecting the on-off state of the switch module when the power device runs and controlling the power device to stop after the on-off time of the switch module is determined to continuously reach the preset time; the preset time is less than the delay separation time of the relay. The embodiment of the invention is used in the process that the contact of the relay is disconnected under high voltage and high current.
Description
Technical Field
The embodiment of the invention relates to the field of frequency converters, in particular to a protection circuit and a protection method of a relay.
Background
In the prior art, the frequency converter is widely applied to equipment such as an air conditioner, a refrigerator and a washing machine, and an alternating current contactor for switching on and off a bus current in the frequency converter can be replaced by an onboard relay, so that interference such as stray inductance caused by too much wiring of the alternating current contactor is avoided.
When the inverter is applied to an air conditioner and an on-board relay is used for switching on and off current, under the condition that a compressor or a motor operates, if the Pressure of a refrigerant in a pipeline exceeds a limit value, the current in the circuit is large, and at the moment, a Pressure Switch (PSH) connected with the pipeline is disconnected. Because the pressure switch is also connected with the control end of the on-board relay, the control end of the on-board relay is also disconnected after the pressure switch is disconnected. At this time, if the large current in the circuit is a current which is obtained by rectifying three-phase power and includes dc and ac current components, the current does not pass through a zero point, that is, when the control end of the on-board relay is turned off, a dc high voltage and a high current are borne between the contacts of the on-board relay.
However, since the withstand current of the on-board relay is smaller as the dc voltage between the contacts of the on-board relay is larger, and the withstand current of the on-board relay is only several hundred milliamperes at the dc voltage after three-phase current rectification, the contacts of the on-board relay are burned when the on-board relay is turned off at a high dc voltage and a high current.
Disclosure of Invention
The invention provides a protection circuit and a method of a relay, which solve the problem that a contact of an on-board relay is burnt when a compressor or a motor runs.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a protection circuit for a relay, the protection circuit comprising: the device comprises a processor, a switch module and a control module.
The first end of the processor is connected with the first end of the switch module, the second end of the switch module is connected with the first end of the control module, and the second end of the control module is used for being connected with the relay; and the second end of the processor is used for connecting the power device.
The control module is used for controlling the relay to be switched off when the switch module is switched off; the processor is used for detecting the on-off state of the switch module when the power device runs and controlling the power device to stop after the on-off time of the switch module is determined to continuously reach the preset time; the preset time is less than the delay separation time of the relay, and the delay separation time is the time from the power failure of the relay to the disconnection of the contact of the relay.
With reference to the first aspect, in one possible implementation manner, the switch module includes: the pressure switch, first resistance, second resistance and electric capacity.
The first end of the first resistor is a first end of the switch module, and the second end of the first resistor is a second end of the switch module. The first end of the first resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded and is also connected with the first end of the pressure switch; the second end of the first resistor is connected with the first end of the second resistor and is also connected with the second end of the pressure switch; the second end of the second resistor is connected with a power supply.
With reference to the first aspect and the foregoing possible implementation manners, in another possible implementation manner, the control module includes: the circuit comprises a first triode, a second triode, a third triode, a fourth triode, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor.
The base electrode of the first triode is the first end of the control module, the emitting electrode of the first triode is grounded, and the collecting electrode of the first triode is connected with the first end of the third resistor;
the base electrode of the second triode is connected with the third end of the processor, the emitting electrode of the second triode is grounded, and the collector electrode of the second triode is connected with the base electrode of the third triode and also connected with the first end of the third resistor and the first end of the fourth resistor respectively; the second end of the third resistor and the second end of the fourth resistor are connected with a power supply;
an emitter of the third triode is grounded, and a collector of the third triode is connected with a first end of the fifth resistor and a first end of the sixth resistor respectively; the second end of the sixth resistor is connected with the base electrode of the fourth triode, the second end of the fifth resistor is connected with the first end of the seventh resistor and also connected with the emitting electrode of the fourth triode, and the second end of the seventh resistor is connected with the power supply; the collector of the fourth triode is the second end of the control module;
the eighth resistor is connected between the base electrode and the emitting electrode of the fourth triode in parallel;
and the control module is specifically used for switching on the first triode, switching off the third triode and switching off the fourth triode when the pressure switch is switched off, so that the relay is controlled to be switched off.
With reference to the first aspect and the foregoing possible implementation manners, in another possible implementation manner, the control module is further configured to, when the pressure switch is not turned off, turn off the first triode, receive a high level output by a third terminal of the processor, turn on the second triode, turn off the third triode, and turn off the fourth triode, so as to control the relay to be turned off.
With reference to the first aspect and the foregoing possible implementation manners, in another possible implementation manner, the control module is further configured to, when the pressure switch is not turned off, turn off the first triode, receive a low level output by a third end of the processor, turn off the second triode, turn on the third triode, and turn on the fourth triode, so as to control the relay to be turned on.
With reference to the first aspect and the possible implementations described above, in another possible implementation, the power device is a compressor or a motor.
In a second aspect, the present invention provides a method for protecting a relay, which is applied to a protection circuit of a relay as described in the first aspect or any one of the possible implementations of the first aspect. The method can comprise the following steps: detecting the on-off state of a pressure switch when the power device runs; when the pressure switch is determined to be disconnected, the relay is controlled to be disconnected; when the disconnection time of the pressure switch is determined to continuously reach the preset time, controlling the power device to stop; the preset time is less than the delay separation time of the relay, and the delay separation time is the time from the power failure of the relay to the disconnection of the contact of the relay.
With reference to the second aspect, in a possible implementation manner, the method may further include: when the disconnection time of the pressure switch is determined to be less than the preset time, judging whether the frequency converter has a fault; if the frequency converter has faults, controlling the power device to stop and outputting an alarm message, wherein the alarm message is used for prompting a user that the frequency converter has faults; if no fault exists, the power plant is kept running.
In a third aspect, the present invention provides a frequency converter, which may include: a protection circuit for a relay as in the first aspect or any one of the possible implementations of the first aspect. And the frequency converter can be applied to equipment such as an air conditioner, a refrigerator and a washing machine.
According to the protection circuit of the relay, the processor can control the power device to stop after the disconnection time of the switch module is determined to continuously reach the preset time, the preset time is less than the delay separation time of the relay, and therefore the current passing through the contact of the relay is close to zero before the contact of the relay is disconnected, so that the contact of the relay can be safely and reliably disconnected and cannot be burnt.
Drawings
Fig. 1 is a schematic diagram of a protection circuit of a relay according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a protection circuit of another relay according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a protection circuit of another relay according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a protection circuit of another relay according to an embodiment of the present invention;
fig. 5 is a flowchart of a method for protecting a relay according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a frequency converter according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic diagram of a protection circuit of a relay according to an embodiment of the present invention, and as shown in fig. 1, the protection circuit of the relay may include: a processor 11, a switch module 12 and a control module 13.
The first end of the processor 11 is connected to the first end of the switch module 12, the second end of the switch module 12 is connected to the first end of the control module 13, and the second end of the control module 13 is used for connecting a relay; and a second end of the processor 11 is used for connecting a power device.
And the control module 13 is used for controlling the relay to be switched off when the switch module 12 is switched off.
And the processor 11 is used for detecting the on-off state of the switch module 12 when the power device runs, and controlling the power device to stop after determining that the off time of the switch module 12 continuously reaches the preset time. The preset time is less than the delay separation time of the relay, and the delay separation time is the time from the power failure of the relay to the disconnection of the contact of the relay.
It should be noted that, in the embodiment of the present invention, the power device may be a compressor or a motor. In addition, the relay related to the embodiment of the invention is a common relay, and is not a high-price direct current relay.
According to the protection circuit of the relay, the processor can control the power device to stop after the disconnection time of the switch module is determined to continuously reach the preset time, the preset time is less than the delay separation time of the relay, and therefore the current passing through the contact of the relay is close to zero before the contact of the relay is disconnected, so that the contact of the relay can be safely and reliably disconnected and cannot be burnt.
Further, in the embodiment of the present invention, as shown in fig. 2, the switch module 12 may include: pressure switch PSH, first resistance, second resistance and electric capacity. Fig. 2 shows an example where the first resistor is R1, the second resistor is R2, and the capacitor is C.
The first terminal of the resistor R1 is the first terminal of the switch module 12, and the second terminal of the resistor R1 is the second terminal of the switch module 12.
The first end of the resistor R1 is connected with the first end of the capacitor C, the second end of the capacitor C is grounded, and the first end of the pressure switch is also connected with the second end of the capacitor C; the second end of the resistor R1 is connected with the first end of the resistor R2 and is also connected with the second end of the pressure switch; the second end of the resistor R2 is connected to a power supply.
Further, in the embodiment of the present invention, as shown in fig. 3, the control module 13 may include: the circuit comprises a first triode, a second triode, a third triode, a fourth triode, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor. In fig. 3, four triodes Q1, Q2, Q3 and Q4, and six resistors R3, R4, R5, R6, R7 and R8 are illustrated as examples.
The base of the transistor Q1 is the first end of the control module 13, the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the first end of the resistor R3.
The base electrode of the triode Q2 is connected with the third end of the processor 11, the emitter electrode of the triode Q2 is grounded, the collector electrode of the triode Q2 is connected with the base electrode of the triode Q3, and the collector electrode of the triode Q2 is also connected with the first end of the resistor R3 and the first end of the resistor R4 respectively; the second end of the resistor R3 and the second end of the resistor R4 are connected to a power supply.
An emitter of the triode Q3 is grounded, and a collector of the triode Q3 is respectively connected with a first end of the resistor R5 and a first end of the resistor R6; the second end of the resistor R6 is connected with the base electrode of the triode Q4, the second end of the resistor R5 is connected with the first end of the resistor R7 and the emitter electrode of the triode Q4, and the second end of the resistor R7 is connected with a power supply; the collector of transistor Q4 is the second terminal of control module 13.
The resistor R8 is connected in parallel between the base and emitter of the transistor Q4.
The control module 13 is specifically configured to, when the pressure switch is turned off, turn on the transistor Q1, turn off the transistor Q3, and turn off the transistor Q4, thereby controlling the relay to be turned off. At this time, whether the third terminal of the processor 11 outputs a high level or a low level, i.e., whether the transistor Q2 is turned on or off, the transistor Q4 is turned off, thereby controlling the relay to be turned off.
It should be noted that, in the embodiment of the present invention, the control module 13 is further configured to, when the pressure switch is not turned off, turn off the transistor Q1, receive a high level output from the third terminal of the processor 11, turn on the transistor Q2, turn off the transistor Q3, and turn off the transistor Q4, thereby controlling the relay to be turned off. Or, the control module 13 is further configured to, when the pressure switch is not turned off, turn off the transistor Q1, receive the low level output by the third terminal of the processor 11, turn off the transistor Q2, turn on the transistor Q3, turn on the transistor Q4, and thereby control the relay to be closed.
To facilitate understanding of those skilled in the art, the present invention will be illustrated by the following embodiments of a protection circuit of a relay.
Illustratively, the processor 11 is a Central Processing Unit (CPU), and the switch module 12 includes: pressure switch PSH, resistors R1 and R2, and capacitor C; the control module 13 includes: the triodes Q1, Q2, Q3 and Q4, the resistors R3, R4, R5, R6, R7 and R8 are shown in a specific circuit diagram in FIG. 4. The triodes Q1, Q2 and Q3 are NPN triodes, and the triode Q4 is a PNP triode.
When PSH is off, the voltage at the base of transistor Q1 is 5 volts (V), and transistor Q1 is on because the emitter of transistor Q1 is grounded and the voltage is 0V. After the transistor Q1 is turned on, the voltage of the collector of the transistor Q1 is 0V, i.e., the voltage of the base of the transistor Q3 is 0V, and since the voltage of the emitter of the transistor Q3 is 0V, which is equal to the voltage of the base, the transistor Q3 is turned off. After the transistor Q3 is turned off, the voltage of the collector of the transistor Q3 is 15V, that is, the voltage of the base of the transistor Q4 is 15V, and since the voltage of the emitter of the transistor Q4 is 15V, which is equal to the voltage of the base, the transistor Q4 is turned off. After the triode Q4 is cut off, the voltage of the collector of the triode Q4 is 0V, and the relay is controlled to be switched off.
When PSH is not turned off, the voltage at the base of the transistor Q1 is 0V, and since the emitter of the transistor Q1 is grounded, the voltage is 0V, and thus the transistor Q1 is turned off. If the third terminal of the CPU outputs a high level, i.e., the base of the transistor Q2 is high, the transistor Q2 is turned on because the emitter of the transistor Q2 is grounded. After the transistor Q2 is turned on, the voltage of the collector of the transistor Q2 is 0V, that is, the voltage of the base of the transistor Q3 is 0V, and since the voltage of the emitter of the transistor Q3 is 0V, the transistor Q3 is turned off. After the transistor Q3 is turned off, the voltage of the collector of the transistor Q3 is 15V, that is, the voltage of the base of the transistor Q4 is 15V, and since the voltage of the emitter of the transistor Q4 is also 15V, the transistor Q4 is turned off. After the triode Q4 is cut off, the voltage of the collector of the triode Q4 is 0V, and the relay is controlled to be switched off.
When PSH is not turned off, the voltage at the base of the transistor Q1 is 0V, and since the emitter of the transistor Q1 is grounded, the voltage is 0V, and thus the transistor Q1 is turned off. If the third terminal of the CPU outputs a low level, i.e., the voltage at the base of the transistor Q2 is 0V, the transistor Q2 is turned off because the emitter of the transistor Q2 is grounded. After the transistors Q1 and Q2 are both turned off, the voltages of the collectors of the transistors Q1 and Q2 are both 5V, that is, the voltage of the base of the transistor Q3 is 5V, and since the voltage of the emitter of the transistor Q3 is 0V, the transistor Q3 is turned on. After the transistor Q3 is turned on, the voltage of the collector of the transistor Q3 is 0V, that is, the voltage of the base of the transistor Q4 is 0V, and since the voltage of the emitter of the transistor Q4 is 15V, the transistor Q4 is turned on. After the triode Q4 is conducted, the voltage of the collector of the triode Q4 is 15V, and the relay is controlled to be closed.
Fig. 5 is a flowchart of a method for protecting a relay according to an embodiment of the present invention, which is applied to a protection circuit of a relay shown in any one of fig. 1 to 4, and as shown in fig. 5, the method includes:
201. and detecting the on-off state of the pressure switch when the power device operates.
202. And when the pressure switch is determined to be disconnected, the relay is controlled to be disconnected.
203. And when the disconnection time of the pressure switch is determined to continuously reach the preset time, controlling the power device to stop.
204. And when the disconnection time of the pressure switch is determined to be less than the preset time, judging whether the frequency converter has a fault.
205. And if the fault exists, controlling the power device to stop and outputting an alarm message.
The alarm message is used for prompting a user that the frequency converter has a fault.
206. If no fault exists, the power plant is kept running.
In this way, the current of the contact of the relay is close to zero before the contact of the relay is opened, so that the contact of the relay can be safely and reliably opened and cannot be burnt.
Fig. 6 is a schematic diagram of a frequency converter according to an embodiment of the present invention, and as shown in fig. 6, the frequency converter may include: a protection circuit for a relay as described in any of figures 1-4.
The frequency converter provided by the embodiment of the invention comprises the protective circuit of the relay, so that the same effect as the protective circuit of the relay can be achieved.
Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions within the technical scope of the present invention are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. A protection circuit of a relay, characterized in that the protection circuit of the relay comprises: the device comprises a processor, a switch module and a control module;
the first end of the processor is connected with the first end of the switch module, the second end of the switch module is connected with the first end of the control module, and the second end of the control module is used for being connected with the relay; the second end of the processor is used for connecting a power device;
the control module is used for controlling the relay to be switched off when the switch module is switched off;
the processor is used for detecting the on-off state of the switch module when the power device runs and controlling the power device to stop after the on-off time of the switch module is determined to continuously reach the preset time; the preset time is less than the delay separation time of the relay, and the delay separation time is the time from the power failure of the relay to the disconnection of the contact of the relay.
2. The relay protection circuit of claim 1, wherein the switch module comprises: the pressure switch, the first resistor, the second resistor and the capacitor;
the first end of the first resistor is a first end of the switch module, and the second end of the first resistor is a second end of the switch module;
the first end of the first resistor is connected with the first end of the capacitor, the second end of the capacitor is grounded, and the second end of the capacitor is also connected with the first end of the pressure switch; the second end of the first resistor is connected with the first end of the second resistor and is also connected with the second end of the pressure switch; and the second end of the second resistor is connected with a power supply.
3. The relay protection circuit of claim 2, wherein the control module comprises: the circuit comprises a first triode, a second triode, a third triode, a fourth triode, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor;
a base electrode of the first triode is a first end of the control module, an emitting electrode of the first triode is grounded, and a collector electrode of the first triode is connected with a first end of the third resistor;
the base electrode of the second triode is connected with the third end of the processor, the emitting electrode of the second triode is grounded, and the collector electrode of the second triode is connected with the base electrode of the third triode and is also respectively connected with the first end of the third resistor and the first end of the fourth resistor; the second end of the third resistor and the second end of the fourth resistor are connected with a power supply;
an emitter of the third triode is grounded, and a collector of the third triode is connected with a first end of the fifth resistor and a first end of the sixth resistor respectively; a second end of the sixth resistor is connected with a base electrode of the fourth triode, a second end of the fifth resistor is connected with a first end of the seventh resistor and also connected with an emitting electrode of the fourth triode, and a second end of the seventh resistor is connected with a power supply; the collector of the fourth triode is the second end of the control module;
the eighth resistor is connected between the base electrode and the emitting electrode of the fourth triode in parallel;
the control module is specifically configured to, when the pressure switch is turned off, turn on the first triode, turn off the third triode, and turn off the fourth triode, so as to control the relay to be turned off.
4. The protection circuit of a relay according to claim 3,
the control module is further configured to, when the pressure switch is not turned off, turn off the first triode, receive the high level output from the third end of the processor, turn on the second triode, turn off the third triode, and turn off the fourth triode, thereby controlling the relay to be turned off.
5. The protection circuit of a relay according to claim 3,
the control module is further configured to, when the pressure switch is not turned off, turn off the first triode, receive the low level output from the third end of the processor, turn off the second triode, turn on the third triode, and turn on the fourth triode, thereby controlling the relay to be closed.
6. The relay protection circuit according to claim 1, wherein the power device is a compressor or a motor.
7. A protection method of a relay applied to a protection circuit of the relay according to any one of claims 1 to 6, characterized by comprising:
detecting the on-off state of a pressure switch when the power device runs;
when the pressure switch is determined to be disconnected, controlling the relay to be disconnected;
when the fact that the off time of the pressure switch continuously reaches the preset time is determined, the power device is controlled to stop; the preset time is less than the delay separation time of the relay, and the delay separation time is the time from the power failure of the relay to the disconnection of the contact of the relay.
8. The method of protecting a relay according to claim 7, further comprising:
when the disconnection time of the pressure switch is determined to be less than the preset time, judging whether the frequency converter has a fault;
if the frequency converter has faults, controlling the power device to stop and outputting an alarm message, wherein the alarm message is used for prompting a user that the frequency converter has faults;
if no fault exists, the power plant is kept running.
9. A frequency converter, characterized in that the frequency converter comprises: protection circuit of a relay according to any of claims 1-6.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811326436.4A CN109545620B (en) | 2018-11-08 | 2018-11-08 | Protective circuit and method of relay |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811326436.4A CN109545620B (en) | 2018-11-08 | 2018-11-08 | Protective circuit and method of relay |
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| CN109545620A CN109545620A (en) | 2019-03-29 |
| CN109545620B true CN109545620B (en) | 2020-02-04 |
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| CN201811326436.4A Active CN109545620B (en) | 2018-11-08 | 2018-11-08 | Protective circuit and method of relay |
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| CN110594953A (en) | 2019-09-09 | 2019-12-20 | 广东美的暖通设备有限公司 | Compressor driving device, compressor pressure protection method and air conditioner |
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| CN201893293U (en) * | 2010-11-29 | 2011-07-06 | 许继集团有限公司 | Arcless switching relay |
| CN203225213U (en) * | 2013-03-22 | 2013-10-02 | 深圳市慧锐通智能电器股份有限公司 | A protecting circuit used for protecting contacts of a relay |
| CN204740985U (en) * | 2015-06-02 | 2015-11-04 | 深圳市新科瑞电气技术有限公司 | A relay control circuit for converter |
| CN108242794A (en) * | 2018-03-08 | 2018-07-03 | 厦门芯阳科技股份有限公司 | A kind of relay contact protection circuit of control inductive load |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030218847A1 (en) * | 2002-01-28 | 2003-11-27 | Vehicle Enhancement Systems, Inc. | Solid state relay/circuit breaker system |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201893293U (en) * | 2010-11-29 | 2011-07-06 | 许继集团有限公司 | Arcless switching relay |
| CN203225213U (en) * | 2013-03-22 | 2013-10-02 | 深圳市慧锐通智能电器股份有限公司 | A protecting circuit used for protecting contacts of a relay |
| CN204740985U (en) * | 2015-06-02 | 2015-11-04 | 深圳市新科瑞电气技术有限公司 | A relay control circuit for converter |
| CN108242794A (en) * | 2018-03-08 | 2018-07-03 | 厦门芯阳科技股份有限公司 | A kind of relay contact protection circuit of control inductive load |
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