CN212380938U - Power-off protection circuit and frequency conversion range hood with same - Google Patents
Power-off protection circuit and frequency conversion range hood with same Download PDFInfo
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- CN212380938U CN212380938U CN202020764197.7U CN202020764197U CN212380938U CN 212380938 U CN212380938 U CN 212380938U CN 202020764197 U CN202020764197 U CN 202020764197U CN 212380938 U CN212380938 U CN 212380938U
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Abstract
The utility model relates to a power-off protection circuit, which is connected between an input power supply and a protected electric functional module and is characterized in that the power-off protection circuit comprises a relay drive circuit, a relay, a PTC resistor, an input voltage monitoring circuit, a first hysteresis comparator and a second hysteresis comparator; the input voltage monitoring circuit is connected with an input power supply, the input ends of the first hysteresis comparator and the second hysteresis comparator are connected with the output end of the input voltage monitoring circuit, and the output ends of the first hysteresis comparator and the second hysteresis comparator are connected with the input end of the relay driving circuit; the relay is provided with a control contact, the relay is connected in front of the protected electric functional module, and the control contact of the relay is connected with the output of the relay driving circuit; the PTC resistor is connected in parallel at two ends of the relay coil. Compared with the prior art, the utility model has the advantages of: the power-off protection circuit can effectively protect the protected electric functional module, is designed by a pure hardware circuit and is quick in response.
Description
Technical Field
The utility model relates to a power-off protection circuit and applied frequency conversion lampblack absorber that has this power-off protection circuit.
Background
With the popularization of the frequency conversion technology and the reduction of the cost, the application prospect of the frequency conversion technology in various occasions becomes very wide, and more household appliances gradually adopt the direct-current frequency conversion technology due to the advantages of stepless speed regulation and small vibration of a Permanent Magnet Synchronous Motor (PMSM).
The range hood adopting the frequency conversion technology has the advantages of good oil smoke absorption effect, low noise and the like. However, the variable frequency driver has complex technology and higher cost, and particularly, an Intelligent Power Module (IPM) used for an inverter part is expensive and has limited bearable electrical stress, and is a core part of the variable frequency driver, and the permanent magnet synchronous motor also has a certain working voltage range. At present, in China, the fluctuation range of the power grid voltage of a certain part of regions is large, even the voltage exceeds 300VAC (420VDC), the operating voltage of the IPM is only 400VDC, and therefore instantaneous large-range voltage fluctuation can instantaneously cause damage to the IPM and even damage to a PMSM motor. It becomes especially important to protect the most expensive IPM components and pmsm components at the core of the inverter drive.
Typical inverter drive topology is shown in fig. 1, and as can be seen from the inverter drive topology shown in fig. 1, when the fluctuation range of the grid voltage is too large, especially when the instantaneous grid voltage exceeds 400VDC, IPM damage may be caused, and the circuit board may also be irreversibly damaged.
SUMMERY OF THE UTILITY MODEL
The utility model discloses the first technical problem that will solve provides a power-off protection circuit to above-mentioned prior art, can protect IPM drive section and PMSM motor when the electric wire netting voltage fluctuation scope is great.
The utility model discloses the technical problem that further solve provides an use frequency conversion lampblack absorber that has above-mentioned power protection circuit.
The utility model provides a technical scheme that above-mentioned technical problem adopted is: a power-off protection circuit is connected between an input power supply and a protected electric functional module and is characterized by comprising a relay drive circuit, a relay, a PTC resistor, an input voltage monitoring circuit, a first hysteresis comparator and a second hysteresis comparator; wherein
The input voltage monitoring circuit is connected with the input power supply and is used for converting the voltage of the input power supply into direct current voltage, recording the voltage of the input power supply as Vac, and recording the output voltage of the input voltage monitoring circuit as Vaco; marking the working upper limit of the input power supply as Vacmax, the working lower limit of the input power supply as Vacmin, the upper limit of the output voltage of the input voltage monitoring circuit as Vacomax, and the upper limit of the output voltage of the input voltage monitoring circuit as Vacom;
the input end of the first hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the upper working limit of the input voltage monitoring circuit, and the comparison threshold value of the first hysteresis comparator is Va1 and Va2, and Va1 is greater than Va 2; when Vacomax is greater than Va1, the first hysteresis comparator acts, and the relay is driven to be disconnected by the relay driving circuit; when Vacomax < Va2, the first hysteresis comparator is recovered, and the relay is driven to be opened and closed by the relay driving circuit;
the input end of the second hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the working lower limit of the input voltage monitoring circuit, and the second hysteresis comparator is connected with the first hysteresis comparator in parallel; the comparison threshold of the second hysteresis comparator is Vb1 and Vb2, and Vb1> Vb 2; when Vacomin < Vb2, the second hysteresis comparator acts, and the relay is driven to be disconnected by the relay driving circuit; when Vacomin > Vb1, the second hysteresis comparator is recovered, and the relay is driven to be closed by the relay driving circuit;
the output ends of the first hysteresis comparator and the second hysteresis comparator are connected with the input end of the relay drive circuit;
the relay is provided with a control contact, the relay is connected in front of the protected electric functional module, the control contact of the relay is connected with the output of the relay driving circuit, and the relay driving circuit drives the relay driving circuit to open or close;
the PTC resistor is connected in parallel at two ends of the relay coil.
The protected electric functional module is an IPM power module and a PMSM motor.
As the improvement, the input power supply and the protected electric functional module further comprise a variable frequency driver, the input end of the variable frequency driver is connected with the input power supply, and the output end of the variable frequency driver is also connected with two ends of the relay coil.
The utility model provides a technical scheme that above-mentioned further technical problem adopted does: the utility model provides a frequency conversion lampblack absorber, includes frequency conversion driver and the motor module who is connected with frequency conversion driver, and frequency conversion driver's input is connected its characterized in that with input power supply: still including the power-off protection circuit who has above-mentioned structure, relay among the power-off protection circuit is connected before the motor module, and variable frequency driver's output and power-off protection circuit's relay coil both ends are connected.
The motor module adopts a permanent magnet synchronous motor based on an IPM power module.
Compared with the prior art, the utility model has the advantages of: the power-off protection circuit can effectively protect the protected electric functional module, is designed by a pure hardware circuit and is quick in response.
Drawings
Fig. 1 is a circuit schematic diagram of a prior art medium frequency drive.
Fig. 2 is a schematic circuit diagram of a power-off protection circuit according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
The power-off protection circuit shown in fig. 2 is connected between an input power supply and a protected electrical functional module, and comprises a relay driving circuit, a relay, a PTC resistor, an input voltage monitoring circuit, a first hysteresis comparator and a second hysteresis comparator; wherein
The input voltage monitoring circuit is connected with the input power supply and is used for converting the voltage of the input power supply into direct current voltage, recording the voltage of the input power supply as Vac, and recording the output voltage of the input voltage monitoring circuit as Vaco; marking the working upper limit of the input power supply as Vacmax, the working lower limit of the input power supply as Vacmin, the upper limit of the output voltage of the input voltage monitoring circuit as Vacomax, and the upper limit of the output voltage of the input voltage monitoring circuit as Vacom;
the input end of the first hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the upper working limit of the input voltage monitoring circuit, and the comparison threshold value of the first hysteresis comparator is Va1 and Va2, and Va1 is greater than Va 2; when Vacomax is greater than Va1, the first hysteresis comparator acts, and the relay is driven to be disconnected by the relay driving circuit; if the motor is in a working state, the temperature of the PTC is rapidly increased due to the existence of large current, the resistance of the PTC is rapidly increased along with the temperature increase, and the PTC bears almost all voltage so as to achieve the purpose of disconnecting a subsequent circuit; when Vacomax < Va2, the first hysteresis comparator is recovered, and the relay is driven to be opened and closed by the relay driving circuit; the latter circuit can be put into normal operation. Va1 and Va2 form a hysteresis interval, so that frequent protection is avoided when the voltage fluctuates slightly.
The input end of the second hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the working lower limit of the input voltage monitoring circuit, and the second hysteresis comparator is connected with the first hysteresis comparator in parallel; the comparison threshold of the second hysteresis comparator is Vb1 and Vb2, and Vb1> Vb 2; when Vacomin < Vb2, the second hysteresis comparator operates, the relay is driven to be disconnected by the relay driving circuit, and if the motor is in a working state, the temperature of the PTC is rapidly increased due to the existence of large current, the resistance of the PTC is rapidly increased along with the temperature increase, and the PTC almost completely bears the voltage, so that the purpose of disconnecting the subsequent circuit is achieved; when Vacomin > Vb1, the second hysteresis comparator is recovered, and the relay is driven to be closed by the relay driving circuit; the latter circuit can be put into normal operation. Vb1 and Vb2 form a hysteresis interval to avoid frequent protection when the voltage fluctuates slightly;
when the input voltage is in the normal range, the relay is closed, so that the back-stage circuit and the motor can work normally;
the output ends of the first hysteresis comparator and the second hysteresis comparator are connected with the input end of the relay drive circuit;
the relay is provided with a control contact, the relay is connected in front of the protected electric functional module, the control contact of the relay is connected with the output of the relay driving circuit, and the relay driving circuit drives the relay driving circuit to open or close;
the PTC resistor is connected in parallel at two ends of the relay coil.
In this embodiment, the protected electrical functional modules are IPM power modules and PMSM motors.
The input power supply and the protected electric functional module further comprise a variable frequency driver, the input end of the variable frequency driver is connected with the input power supply, and the output end of the variable frequency driver is also connected with the two ends of the relay coil.
The power-off protection circuit in the embodiment is applied to the variable-frequency range hood, the protected electric function module is the motor module of the variable-frequency range hood, and the motor module adopts a permanent magnet synchronous motor based on an IPM power module.
Claims (5)
1. A power-off protection circuit is connected between an input power supply and a protected electric functional module and is characterized by comprising a relay drive circuit, a relay, a PTC resistor, an input voltage monitoring circuit, a first hysteresis comparator and a second hysteresis comparator; wherein
The input voltage monitoring circuit is connected with the input power supply and is used for converting the voltage of the input power supply into direct current voltage, recording the voltage of the input power supply as Vac, and recording the output voltage of the input voltage monitoring circuit as Vaco; marking the working upper limit of the input power supply as Vacmax, the working lower limit of the input power supply as Vacmin, the upper limit of the output voltage of the input voltage monitoring circuit as Vacomax, and the upper limit of the output voltage of the input voltage monitoring circuit as Vacom;
the input end of the first hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the upper working limit of the input voltage monitoring circuit, and the comparison threshold value of the first hysteresis comparator is Va1 and Va2, and Va1 is greater than Va 2; when Vacomax is greater than Va1, the first hysteresis comparator acts, and the relay is driven to be disconnected by the relay driving circuit; when Vacomax < Va2, the first hysteresis comparator is recovered, and the relay is driven to be opened and closed by the relay driving circuit;
the input end of the second hysteresis comparator is connected with the output end of the input voltage monitoring circuit and is used for monitoring the working lower limit of the input voltage monitoring circuit, and the second hysteresis comparator is connected with the first hysteresis comparator in parallel; the comparison threshold of the second hysteresis comparator is Vb1 and Vb2, and Vb1> Vb 2; when Vacomin < Vb2, the second hysteresis comparator acts, and the relay is driven to be disconnected by the relay driving circuit; when Vacomin > Vb1, the second hysteresis comparator is recovered, and the relay is driven to be closed by the relay driving circuit;
the output ends of the first hysteresis comparator and the second hysteresis comparator are connected with the input end of the relay drive circuit;
the relay is provided with a control contact, the relay is connected in front of the protected electric functional module, the control contact of the relay is connected with the output of the relay driving circuit, and the relay driving circuit drives the relay driving circuit to open or close;
the PTC resistor is connected in parallel at two ends of the relay coil.
2. The power-off protection circuit of claim 1, wherein: the protected electric functional module is an IPM power module and a PMSM motor.
3. The power-off protection circuit of claim 2, wherein: the input power supply and the protected electric functional module further comprise a variable frequency driver, the input end of the variable frequency driver is connected with the input power supply, and the output end of the variable frequency driver is also connected with the two ends of the relay coil.
4. A frequency conversion lampblack absorber that uses as claim 1 the power-off protection circuit, includes frequency conversion driver and the motor module who is connected with frequency conversion driver, and frequency conversion driver's input is connected with input power supply, its characterized in that: the power-off protection circuit of claim 1, wherein a relay in the power-off protection circuit is connected in front of the motor module, and the output end of the variable-frequency driver is connected with two ends of a relay coil of the power-off protection circuit.
5. The variable frequency range hood according to claim 4, wherein: the motor module adopts a permanent magnet synchronous motor based on an IPM power module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020764197.7U CN212380938U (en) | 2020-05-11 | 2020-05-11 | Power-off protection circuit and frequency conversion range hood with same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020764197.7U CN212380938U (en) | 2020-05-11 | 2020-05-11 | Power-off protection circuit and frequency conversion range hood with same |
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| Publication Number | Publication Date |
|---|---|
| CN212380938U true CN212380938U (en) | 2021-01-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020764197.7U Active CN212380938U (en) | 2020-05-11 | 2020-05-11 | Power-off protection circuit and frequency conversion range hood with same |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117579043A (en) * | 2023-11-28 | 2024-02-20 | 北京伽略电子股份有限公司 | Voltage comparator with hysteresis function |
-
2020
- 2020-05-11 CN CN202020764197.7U patent/CN212380938U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117579043A (en) * | 2023-11-28 | 2024-02-20 | 北京伽略电子股份有限公司 | Voltage comparator with hysteresis function |
| CN117579043B (en) * | 2023-11-28 | 2024-05-31 | 北京伽略电子股份有限公司 | Voltage comparator with hysteresis function |
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