CN214848454U

CN214848454U - Undervoltage and shunt release based on microcontroller and electromagnet driving circuit

Info

Publication number: CN214848454U
Application number: CN202120768950.4U
Authority: CN
Inventors: 陈丕铸
Original assignee: Zhejiang Tenor Power Equipment Co ltd
Current assignee: Zhejiang Tenor Power Equipment Co ltd
Priority date: 2021-04-15
Filing date: 2021-04-15
Publication date: 2021-11-23
Anticipated expiration: 2031-04-15

Abstract

The utility model relates to a low pressure distribution protection technical field specifically is an electromagnet drive circuit, including the incoming end, the incoming end is connected with first diode, the last parallelly connected electro-magnet that has of first diode, first diode is connected with the MOS pipe, a serial communication port, the one end of MOS pipe is connected with push-pull circuit, the PWM port is connected to push-pull circuit's one end, and wherein the PWM port setting is on microcontroller. Still provide an undervoltage, shunt release based on microcontroller in addition, the utility model discloses fuse undervoltage protection, shunt function in an organic whole and adopt the actuation maintenance power and the power consumption of PWM technique dynamic adjustment electro-magnet, reduced product cost, consumption, improved reliability and life.

Description

Undervoltage and shunt release based on microcontroller and electromagnet driving circuit

Technical Field

The utility model relates to a low pressure distribution protection technical field, concretely relates to under-voltage, shunt release and an electro-magnet drive circuit based on microcontroller.

Background

The main fault protection device of a low voltage distribution network is a circuit breaker. To satisfy section 2 of GB/T14048.2 low-voltage switchgear and control device: the circuit breaker is generally provided with functions of overcurrent fault protection, undervoltage fault protection, earth fault protection and the like according to the requirements of the circuit breaker; the shunt and close functions are also configured for the local or remote control of the circuit breaker. These functions all employ electromagnets as actuators.

However, most of the current circuit breakers control the electromagnet by directly applying an alternating current or direct current power supply to complete the attraction, the holding and the release. In the mode, the power consumption is large, the temperature is increased, the service life of the product is short, and the fault phenomenon that the electromagnet coil is burnt out frequently occurs; and secondly, the release voltage is inaccurate, and accurate undervoltage protection is difficult to realize.

In order to solve the problems of large power consumption and high temperature rise, a driving circuit shown in fig. 1 is adopted for some products, namely, the [ Q6] is switched on and off in the [ Q5] during the pull-in action, and the [ Q6] is switched on and off in the protection stage [ Q5 ]. The essence of the solution is that the voltage at two ends of the electromagnet is limited by a resistor [ R6] so as to reduce the maintenance power consumption of the electromagnet and reduce the temperature rise of electromagnetic flux; however, the resistance introduces additional power consumption, and the variation of the driving voltage significantly affects the sustaining force of the electromagnetic flux, thereby reducing the reliability.

In addition, one circuit breaker is provided with a plurality of electromagnets, and the structure of the product is bulky. Whether the same electromagnetic flux can execute more than one function is also a problem of the utility model.

Disclosure of Invention

In view of the above, the present invention utilizes the combination of Digital Control (DC) technology and PWM technology to mainly solve the problems of large power consumption, high temperature rise, unstable holding power, etc. of the release in the holding stage. Meanwhile, in order to solve the problem of swelling, the functions of the shunt release are integrated into the under-voltage release, so that the dual functions are perfectly realized without conflict, and the product cost is also reduced remarkably.

In order to achieve the above object, the utility model provides a following technical scheme: the utility model provides an electromagnet driving circuit, includes the incoming end, the incoming end is connected with first diode, the last parallelly connected electro-magnet that has of first diode, first diode is connected with the MOS pipe, wherein the one end of MOS pipe is connected with push-pull circuit, the PWM port is connected to the one end of push-pull circuit, and wherein the PWM port sets up on microcontroller.

Based on the above technical scheme, the utility model discloses further set up, the push-pull circuit includes first triode, second triode, the one end of MOS pipe respectively with first triode and second triode emitter connection, be connected with the third triode after the base of first triode and second triode links to each other, the base of third triode with the PWM port is connected, wherein be provided with first resistance between first triode and the third triode; the base of the third triode is connected with a first branch and a second branch, a second resistor connected with the PWM port is arranged on the first branch, a third resistor is arranged on the second branch, and the other end of the third resistor is grounded.

Based on the technical scheme, the utility model discloses further set up, still including second diode and the first electric capacity that is located incoming end one side, the other one end ground connection of first electric capacity.

The electromagnet driving circuit consists of an energy storage circuit, a switching circuit and a follow current circuit. The energy storage circuit provides enough energy for driving the electromagnet, and the input of the switching circuit is connected to a PWM signal output pin of the microcontroller, and the output of the switching circuit is connected to the electromagnet. The freewheel circuit is used to release the energy stored in the electromagnet during the switching circuit is switched off.

And three triodes in the push-pull circuit are additionally arranged and used for receiving a 3.3V level or pulse signal from the microcontroller and converting the level or pulse signal into a 9V level or pulse signal.

Furthermore the utility model also provides an undervoltage, shunt release based on microcontroller, include as above electromagnet drive circuit.

Based on the technical scheme, the utility model discloses further set up, still include shunt signal interface circuit for receive shunt signal and convert the high-low level of corresponding voltage level system into, and feed back to microcontroller; and

the shunt master signal circuit sends a shunt signal to the shunt signal interface circuit; the shunt signal interface circuit is connected with the microcontroller, and the shunt master signal circuit is connected with the shunt signal interface circuit.

The shunt signal interface circuit comprises a first branch and a second branch, the first branch and the second branch are connected with a photoelectric coupler, a resistor A on the first branch is connected with one end of a light emitting diode of the photoelectric coupler, a resistor B on the second branch is connected with the other end of the light emitting diode of the photoelectric coupler, a drain electrode of a phototriode of the photoelectric coupler is connected with a power supply, a source electrode of the phototriode of the photoelectric coupler is connected with a resistor C and then grounded, and a drain electrode of the phototriode of the photoelectric coupler is also connected with a capacitor A and then grounded.

Based on the technical scheme, the utility model discloses further set up, still include power supply circuit for provide voltage;

the power supply voltage detection circuit is used for detecting a voltage value in the power supply circuit and feeding the voltage value back to the microcontroller;

the driving voltage detection circuit is used for detecting a voltage value in the electromagnet driving circuit and feeding the voltage value back to the microcontroller;

the power supply circuit is connected with the electromagnet driving circuit, the power supply voltage detection circuit is respectively connected with the electromagnet driving circuit and the microcontroller, and the driving voltage detection circuit is respectively connected with the electromagnet driving circuit and the microcontroller.

Based on the technical scheme, the utility model discloses further set up, power supply circuit includes rectifier circuit and DC/DC step-down circuit, rectifier circuit respectively with electromagnet drive circuit and DC/DC step-down circuit connect, wherein DC/DC step-down circuit exports first voltage and second voltage after stepping down high voltage power supply, first voltage is used for electromagnet drive circuit, the second voltage is used for microcontroller, shunt signal circuit.

Based on the technical scheme, the utility model discloses further set up, supply voltage detection circuitry and drive voltage detection circuitry with microcontroller's ADC pin is connected.

Based on the technical scheme, the utility model discloses further set up, shunt signal interface circuit with microcontroller's standard IO pin is connected.

The utility model has the advantages that: sampling the voltage of an electromagnet driving circuit in real time and adjusting the duty ratio of a PWM signal according to the voltage, wherein when the driving voltage is high, the duty ratio of the PWM signal is low; on the contrary, when the driving voltage is low, the duty ratio of the PWM signal is high, so that the temperature rise of the electromagnet coil can be reduced, and the temperature of the coil is ensured not to exceed the working temperature of the enameled wire. Otherwise, turn-to-turn breakdown of the electromagnet coil can be caused, and the product can be failed.

Secondly, the duty ratio of the PWM signal is adjusted according to the rule, a relatively constant pull-in maintaining force can be maintained, the fact that the circuit breaker keeps pull-in continuously under the condition of receiving the maximum vibration without misoperation is guaranteed, and therefore the reliability of the under-voltage protection function is guaranteed.

Thirdly, the function that shunt release that the configuration was gone up to the circuit breaker was only a subset of undervoltage release function, consequently can be with the function integration of shunt release to the undervoltage release in, the utility model discloses newly-increased and the interface of shunt function master circuit in the circuit, the electro-magnet action that utilizes undervoltage release accomplishes the shunt function to reduce the configuration of an electro-magnet, the cost is reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 shows a conventional electromagnet attraction and hold circuit;

fig. 2 shows an electromagnet driving circuit according to an embodiment of the present invention;

fig. 3 is a functional block diagram of the structure of the embodiment of the present invention;

fig. 4 is a signal pattern of the PWM output of the microcontroller according to the embodiment of the present invention;

fig. 5 is a shunt master signal interface circuit according to an embodiment of the present invention;

fig. 6 is a flow chart of the operation of the shunt tripping function of the present invention.

Reference numerals: 10. a first diode; 20. a second diode; 30. an MOS tube; 40. an electromagnet; 50. A first triode; 60. a second triode; 70. a third triode; 80. a first resistor; 90. a second resistor; 100. a third resistor; 110. a first capacitor; 120. a power supply circuit; 1201. a rectifying circuit; 1202. a DC/DC voltage reduction circuit; 130. an electromagnet drive circuit; 140. a drive voltage detection circuit; 150. a microcontroller; 160. a shunt signal interface circuit; 1601. a first branch; 1602. a second branch circuit; 1603. a photoelectric coupler; 1604. a resistance A; 1605. a resistance B; 1606. a resistance C; 1607. A capacitor A; 170. a parameter setting circuit; 180. a power supply voltage detection circuit;

Detailed Description

Embodiments of the present application will be described in detail with reference to the drawings and examples, so that how to implement technical means to solve technical problems and achieve technical effects of the present application can be fully understood and implemented.

Fig. 1 shows an electromagnet driving circuit in the prior art; based on the problem that above-mentioned electromagnet drive circuit exists, the utility model provides a following technical scheme, refer to fig. 2, an electromagnet drive circuit, including the incoming end, the incoming end is connected with first diode 10, it has electro-magnet 40 to connect in parallel on the first diode 10, first diode 10 is connected with MOS pipe 30, wherein MOS pipe 30's one end is connected with the circuit of pushing and pulling, the PWM port is connected to the one end of the circuit of pushing and pulling, and wherein the PWM port setting is on microcontroller 150.

The push-pull circuit comprises a first triode and a second triode 60, one end of the MOS tube 30 is respectively connected with the emitters of the first triode 50 and the second triode 60, the bases of the first triode 50 and the second triode 60 are connected and then connected with a third triode 70, the base of the third triode 70 is connected with the PWM port, and a first resistor 80 is arranged between the first triode 50 and the third triode 70; the base of the third triode 70 is connected with a first branch and a second branch, the first branch is provided with a second resistor 90 connected with the PWM port, the second branch is provided with a third resistor 100, and the other end of the third resistor 100 is grounded. The push-pull circuit further comprises a second diode 20 and a first capacitor 110 at one side of the access terminal, and the other end of the first capacitor 110 is grounded.

The electromagnet driving circuit 130 can be regarded as being composed of an energy storage circuit, a switch circuit and a continuous current circuit. The tank circuit provides sufficient energy to drive the electromagnet 40, the switching circuit has an input connected to the PWM signal output pin of the microcontroller 150 and an output connected to the electromagnet 40, and the free-wheeling circuit is used to release the energy stored in the electromagnet 40 during the off period of the switching circuit.

Three triodes in the push-pull circuit are additionally arranged and used for receiving a 3.3V level or pulse signal from the microcontroller 150 and converting the signal into a 9V level or pulse signal.

As shown in fig. 3, in addition, the present invention also provides an undervoltage and shunt release based on the microcontroller 150, which includes the electromagnet driving circuit 130 as described above.

The trip unit further includes a shunt signal interface circuit 160 for receiving the shunt signal, converting the shunt signal into a high level and a low level of a corresponding voltage level system, and feeding back the high level and the low level to the microcontroller 150; and a shunt master signal circuit that sends a shunt signal to the shunt signal interface circuit 160; the shunt signal interface circuit 160 is connected to the microcontroller 150, and the shunt master signal circuit is connected to the shunt signal interface circuit 160. Additionally included is a power circuit 120 for providing a voltage; a power supply voltage detection circuit 180 for detecting the voltage value in the power supply circuit 120 and feeding back to the microcontroller 150; a driving voltage detection circuit 140 for detecting the voltage value in the electromagnet driving circuit 130 and feeding back the voltage value to the microcontroller 150; the power circuit 120 is connected to the electromagnet driving circuit 130, the power voltage detection circuit 180 is respectively connected to the electromagnet driving circuit 130 and the microcontroller 150, and the driving voltage detection circuit 140 is respectively connected to the electromagnet driving circuit 130 and the microcontroller 150.

The shunt signal interface circuit 160 includes a first branch 1601 and a second branch 1602, the first branch 1601 and the second branch 1602 are connected with a photoelectric coupler 1603, a resistor a1604 on the first branch 1601 is connected with one end of a light emitting diode of the photoelectric coupler 1603, a resistor B1605 on the second branch 1602 is connected with the other end of the light emitting diode of the photoelectric coupler 1603, a drain of a phototransistor of the photoelectric coupler 1603 is connected with a power supply, a source of the phototransistor of the photoelectric coupler 1603 is connected with a resistor C1606 and then grounded, and a drain of the phototransistor of the photoelectric coupler 1603 is also connected with a capacitor a1607 and then grounded.

The power circuit 120 includes a rectifying circuit 1201 and a DC/DC voltage-reducing circuit 1202, the rectifying circuit 1201 is connected to the electromagnet driving circuit 130 and the DC/DC voltage-reducing circuit 1202 respectively, wherein the DC/DC voltage-reducing circuit 1202 reduces the voltage of the high-voltage power supply and outputs a first voltage and a second voltage, the first voltage is used for the electromagnet driving circuit 130, and the second voltage is used for the microcontroller 150 and the shunt signal circuit.

The power voltage detection circuit 180 and the driving voltage detection circuit 140 are connected to an ADC pin of the microcontroller 150. The shunt signal interface circuit 160 is connected to standard I/O pins of the microcontroller 150.

Specifically speaking, the utility model discloses by power supply circuit 120, mains voltage detection circuit 180, drive voltage detection circuit 140, microcontroller 150 circuit, electro-magnet drive circuit 130, parameter setting circuit 170, shunt excitation signal interface circuit 160, several parts of electro-magnet 40 constitute.

The power supply circuit 120 is composed of a rectifying circuit 1201 and a DC/DC voltage-reducing circuit 1202, and a part of the output of the rectifying circuit 1201 is connected to the electromagnet driving circuit 130 and the other part is connected to the DC/DC voltage-reducing circuit 1202. The DC/DC voltage reduction device reduces the high voltage and stably outputs a 9V power supply and a 3.3V power supply; the 9V power supply is used for the magnet driving circuit 130, and the 3.3V power supply is used for circuits such as a microcontroller 150 circuit, a parameter setting circuit 170, a shunt signal interface circuit 160 and the like.

The power supply voltage detection circuit 180 and the driving voltage detection circuit 140 have the same structure, but different detection signal introduction points, and the power supply voltage and the driving circuit voltage are reduced to below 3.3V by using a typical resistance-capacitance network, filtered and connected to an ADC pin of the microcontroller 150 circuit.

The shunt signal interface circuit 160 converts the signal from the shunt master circuit into a high/low level corresponding to a 3.3V level system, and connects to a standard I/O pin of the microcontroller 150 circuit.

The principle of the utility model is as follows: when the release is connected to the 220V or 380V main circuit, the microcontroller 150 samples and calculates the effective voltage value of the main circuit in real time, and sends high/low level according to a preset threshold value to control the electromagnet driving circuit 130 to attract/release the electromagnet 40. When the electromagnet 40 is attracted, the microcontroller 150 samples and calculates the voltage value of the electromagnet driving circuit 130 in real time, and adjusts the duty ratio of the PWM signal in real time according to the voltage level. The purpose and effect are as follows: sampling the voltage of the electromagnet driving circuit 130 in real time and adjusting the duty ratio of the PWM signal according to the voltage, wherein when the driving voltage is high, the duty ratio of the PWM signal is low; on the contrary, when the driving voltage is low, the duty ratio of the PWM signal is high, so that the temperature rise of the coil of the electromagnet 40 can be reduced, and the temperature of the coil is ensured not to exceed the working temperature of the enamel wire. Otherwise, turn-to-turn breakdown of the electromagnet 40 coil may occur, resulting in product failure. Secondly, the duty ratio of the PWM signal is adjusted according to the rule, a relatively constant pull-in maintaining force can be maintained, the fact that the circuit breaker keeps pull-in continuously under the condition of receiving the maximum vibration without misoperation is guaranteed, and therefore the reliability of the under-voltage protection function is guaranteed.

In addition, the shunt signal interface circuit 160 is connected to a shunt control master circuit, when the master circuit is activated, the shunt signal interface circuit 160 outputs a high level to the microcontroller 150, and the microcontroller 150 immediately sends a low level signal to control the electromagnet driving circuit 130 to release the electromagnet 40 to complete the shunt action when detecting the signal. Because the function that the shunt release of configuration was accomplished on the circuit breaker is a subset of undervoltage release function, consequently can be with the function integration of shunt release to undervoltage release in, the utility model discloses newly-increased and the interface of shunt function master circuit in the circuit, utilize the electro-magnet 40 action of undervoltage release to accomplish the shunt function to reduce the configuration of an electro-magnet 40, the cost is reduced.

In addition, the utility model also provides a microcontroller-based duty ratio adjustment method of the PWM signal of the undervoltage shunt release, which comprises the following steps that after the release is connected to 220V or 380V, the microcontroller circuit samples and calculates the current grid voltage Vac (Vac in figure 2) through an ADC port connected to the power supply voltage detection circuit; judging a current power grid voltage Vac calculated value, and if the current power grid voltage Vac calculated value is not lower than 80% of a power grid voltage rated value, sending a pull-in level signal through a PWM port and continuing for 320ms to wait for pull-in action completion; the microcontroller circuit then samples and calculates the current drive voltage Vpp (Vpp in fig. 2) via an ADC port connected to the drive voltage detection circuit, and adjusts the duty cycle of the PWM pulses according to the calculated value of the drive voltage Vpp, wherein the duty cycle uses the following calculation equation:

wherein:

D_max: is U_minA corresponding duty cycle; u shape_minThe lowest power grid voltage of attraction must be maintained after the attraction action of the electromagnet is finished;

U_pp: is the calculated electromagnet drive voltage; d_min: is in the range of 1.25U_eDuty ratio of above, U_eIs the rated voltage of the power grid;

in a particular embodiment, D_max、D_minThe isoparametric needs to obtain data after testing the working condition of the electromagnet, and the theoretical calculation is unreliable because the magnetic circuits, coil inductances and resistances of different electromagnets are different. In this example, D_maxCorresponding to 0.2U_eLower than 0.35U specified in GB/T14048.2_e. The K value is 70-99%, and the selection is carried out according to the working condition of the electromagnet;

fig. 4 illustrates a PWM waveform diagram of the trip unit in a normal power-up to under-voltage condition. In the under-voltage delay stage, the duty ratio of the PWM signal increases according to the above calculation equation due to the voltage decrease.

In the shunt trip function of this embodiment, the shunt master signal interface circuit shown in fig. 5 converts the master signal into a 3.3V level in an isolated manner, which is received by the microcontroller. When the microcontroller receives the shunt master command signal, the shunt trip function is executed according to the flow shown in fig. 6.

Certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect.

More uses such as 10, the first diode; 20. a second diode; 30. an MOS tube; 40. an electromagnet; 50. a first triode; 60. a second triode; 70. a third triode; 80. a first resistor; 90. a second resistor; 100. a third resistor; 110. a first capacitor; 120. a power supply circuit; 1201. a rectifying circuit; 1202. a DC/DC voltage reduction circuit; 130. an electromagnet drive circuit; 140. a drive voltage detection circuit; 150. a microcontroller; 160. a shunt signal interface circuit; 1601. a first branch; 1602. a second branch circuit; 1603. a photoelectric coupler; 1604. a resistance A; 1605. a resistance B; 1606. a resistance C; 1607. A capacitor A; 170. a parameter setting circuit; 180. it should be noted that terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

While the foregoing description shows and describes several preferred embodiments of the invention, it is to be understood, as noted above, that the invention is not limited to the forms disclosed herein, but is not intended to be exhaustive or to exclude other embodiments and may be used in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be limited only by the claims appended hereto.

Claims

1. The utility model provides an electromagnet drive circuit, includes the incoming end, the incoming end is connected with first diode, the last parallelly connected electro-magnet of having of first diode, first diode is connected with the MOS pipe, its characterized in that, the one end of MOS pipe is connected with push-pull circuit, the PWM port is connected to push-pull circuit's one end, and wherein the PWM port setting is on microcontroller.

2. The electromagnet driving circuit according to claim 1, wherein the push-pull circuit comprises a first triode and a second triode, one end of the MOS transistor is connected to the emitters of the first triode and the second triode respectively, a third triode is connected after the bases of the first triode and the second triode are connected, the base of the third triode is connected to the PWM port, and a first resistor is arranged between the first triode and the third triode; the base of the third triode is connected with a first branch and a second branch, a second resistor connected with the PWM port is arranged on the first branch, a third resistor is arranged on the second branch, and the other end of the third resistor is grounded.

3. The electromagnet driving circuit according to claim 2, further comprising a second diode and a first capacitor on the side of the input terminal, wherein the other terminal of the first capacitor is grounded.

4. An undervoltage, shunt release based on a microcontroller, characterized in that it comprises an electromagnet drive circuit according to any of claims 1 to 3.

5. The microcontroller-based undervoltage, shunt trip of claim 4, further comprising

The shunt signal interface circuit is used for receiving shunt signals, converting the shunt signals into high and low levels of a corresponding voltage level system and feeding back the high and low levels to the microcontroller; and

the shunt master signal circuit sends a shunt signal to the shunt signal interface circuit; the shunt excitation signal interface circuit is connected with the microcontroller, and the shunt excitation master signal circuit is connected with the shunt excitation signal interface circuit;

6. The microcontroller-based undervoltage, shunt trip of claim 5, further comprising a power supply circuit for providing a voltage;

7. The microcontroller-based undervoltage shunt release of claim 6, wherein the power supply circuit comprises a rectifying circuit and a DC/DC voltage-dropping circuit, the rectifying circuit is connected to the electromagnet driving circuit and the DC/DC voltage-dropping circuit, respectively, wherein the DC/DC voltage-dropping circuit drops a high-voltage power supply and outputs a first voltage and a second voltage, the first voltage is used for the electromagnet driving circuit, and the second voltage is used for the microcontroller and the shunt signal circuit.

8. The microcontroller-based brown-out, shunt release of claim 7, wherein the supply voltage detection circuit and the drive voltage detection circuit are connected to ADC pins of the microcontroller.

9. The microcontroller-based brown-out, shunt release of claim 8, wherein the shunt signal interface circuit interfaces with standard I/O pins of the microcontroller.