阅读说明：本技术 本安电压接力延长装置 (Intrinsic safety voltage relay prolonging device ) 是由 董建国 周兴东 李艳民 于 2020-06-29 设计创作，主要内容包括：本发明公开了一种本安电压接力延长装置,是由本安电源、本安电压延长器和传输电缆组成,主要针对本安电源连接长距离传输电缆且对本安电压升压时,出现开关电源启动电流大导致本安电源易产生过流保护,以及开关电源和电缆的电感会影响本安火花性能的问题。其特点是本安电源内增加了两个针对开关电源的电感和启动电流的功能模块,而本安电压延长器(其输入输出电压都是本安电压)兼有在线供电和备用供电两种模式(优先使用在线供电模式),且可以根据负载耗电情况分电压等级调整其输出的本安电压范围,以及开关电源升压完成后再接通负载的工作方式,使本延长装置在爆炸性环境的任何场合中都可以有效地提高传输电缆末端本安电压。(The invention discloses an intrinsic safety voltage relay extension device which comprises an intrinsic safety power supply, an intrinsic safety voltage extender and a transmission cable and mainly aims at the problems that when the intrinsic safety power supply is connected with a long-distance transmission cable and the intrinsic safety voltage is boosted, the intrinsic safety power supply is easy to generate over-current protection due to large starting current of a switch power supply, and the inductance of the switch power supply and the inductance of the cable can influence the intrinsic safety spark performance. The power supply voltage extender is characterized in that two functional modules aiming at the inductance and the starting current of the switching power supply are added in the intrinsic safety power supply, the intrinsic safety voltage extender (the input and output voltages of the intrinsic safety voltage extender are both in an online power supply mode and a standby power supply mode (the online power supply mode is preferentially used), the output intrinsic safety voltage range of the intrinsic safety voltage extender can be adjusted according to the voltage class of the power consumption condition of a load, and the working mode that the switching power supply is connected with the load after the voltage boosting is finished is adopted, so that the intrinsic safety voltage at the tail end of a transmission cable can be effectively improved in any occasion of explosive environments.)

1. An intrinsically safe voltage relay extension device comprises an intrinsically safe power supply, a non-intrinsically safe power supply connected with an input end of the intrinsically safe power supply, and an intrinsically safe voltage extender, wherein intrinsically safe voltage output by the intrinsically safe power supply provides input voltage for the intrinsically safe voltage extender through a first transmission cable, and intrinsically safe voltage output by the intrinsically safe voltage extender supplies power for a second transmission cable and a sensor;

the method is characterized in that:

the intrinsically safe power supply comprises an inductive pulse sensitive detection module and a frequency accumulation and counting time delay module which are sequentially connected in series;

the intrinsic safety voltage extender is formed by connecting an intrinsic safety voltage standby power supply circuit, a standby power supply output switch and an intrinsic safety voltage online power supply circuit which are sequentially connected in series in parallel, the intrinsic safety voltage online power supply circuit and the intrinsic safety voltage standby power supply circuit are connected at input ports and connected with an input end Vin of the intrinsic safety voltage extender, and an output end of the standby power supply output switch is connected with an output end of the intrinsic safety voltage online power supply circuit and connected with an output end Vout of the intrinsic safety voltage extender.

2. The intrinsically safe voltage relay force extension device of claim 1, wherein: the inductive pulse sensitive detection module comprises a directional coupler PWU1, a resistor PWR1, a resistor PWR2, a resistor PWR3, a resistor PWR4, an N-channel field effect transistor PWQ1, a capacitor PWC1, an inductor PWL1 and a high-speed Schmidt trigger PWU2, wherein the directional coupler is connected with the grid electrode of the field effect transistor PWQ1 through a resistor PWR1, the grid electrode of the field effect transistor PWQ1 is grounded through the resistor PWR2 and is connected with +5V through a resistor PWR4, the source electrode of the field effect transistor PWQ1 is grounded, the drain electrode of the field effect transistor PWQ1 is connected with +5V through a resistor PWR3, the drain electrode of the field effect transistor PWQ1 is connected with a pin 1 of the high-speed Schmidt trigger PWU2 through an inductor PWL1, the capacitor PWC1 is connected with the drain electrode of the field effect transistor PWQ1 and the delay time module 2 of the high-speed Schmidt trigger PWU 2;

the number accumulation counting time delay module is realized by programming of a single chip microcomputer and comprises three timers and a number accumulator.

3. The intrinsically safe voltage relay force extension device of claim 1, wherein: the standby intrinsic safety voltage power supply circuit is composed of an intrinsic safety voltage circuit and an intrinsic safety voltage processing circuit which are sequentially connected in series, and the output end of the standby intrinsic safety voltage power supply circuit is connected with the standby power supply output switch.

4. The intrinsically safe voltage relay force extension device of claim 1, wherein: the intrinsic safety voltage online power supply circuit consists of a P-channel field effect transistor Q3, the source electrode of the intrinsic safety voltage online power supply circuit is connected with the input end Vin of the intrinsic safety voltage extender, the drain electrode of the intrinsic safety voltage online power supply circuit is connected with the cathode of a diode D2 and is connected with the output end Vout of the intrinsic safety voltage extender, and the grid electrode of the intrinsic safety voltage online power supply circuit is connected with the output control signal CTR1 of the single chip microcomputer; the single chip microcomputer can realize the online power supply mode and the standby power supply mode by controlling the CTR1 and the CTR2, and preferentially uses the online mode for power supply.

5. The intrinsically safe voltage relay force extension device of claim 3, wherein: the standby power supply output switch consists of a P-channel field-effect tube Q4 and a diode D2, the source electrode of the field-effect tube Q4 is connected with the output voltage Vo of the intrinsic safety voltage processing circuit, the drain electrode of the field-effect tube Q4 is connected with the anode of the diode D2, the grid electrode of the field-effect tube Q3526 is connected with a single chip microcomputer output control signal CTR2, and the cathode electrode of the diode D2 is connected with the drain electrode of the field-effect tube Q3 and connected to the output end Vout; the single chip microcomputer can realize the working mode that the load is not supplied with power by controlling the CTR2, the switching power supply is started firstly, and the load is switched on after the voltage boosting is finished and Vo is stable.

6. The intrinsically safe voltage relay force extension device of claim 3, wherein: the intrinsic safety voltage-stabilizing circuit comprises a configuration circuit of a diode D3, a field-effect tube Q5, a field-effect tube Q2 and voltage-stabilizing controllers U1 and U1 which are connected in the forward direction, wherein the cathode of a diode D3 is connected with the source electrode of the field-effect tube Q5, and the anode of a diode D3 is connected with Vin; the drain electrode of the field effect transistor Q5 is connected with a pin VIN 1 of U1, and the grid electrode is connected with CTR 3; the drain electrode of the field effect transistor Q2 is connected with a pin 7 UVLO of the U1, the source electrode of the field effect transistor Q2 is grounded, and the gate electrode of the field effect transistor Q2 is connected with the CTR4 and is grounded through a resistor Rx 1; a pin OUT 5 of the U1 is connected with a grid G of a field effect transistor Q1, and an inductor L1 is connected between a pin Vin 1 of the U1 and a drain electrode of the field effect transistor Q1; the source S of the field effect transistor Q1 is grounded through a resistor Rsns; a diode D1 is connected between the drain D of the field effect transistor Q1 and the input end of the intrinsically safe voltage processing circuit, a resistor Rfb2 is connected between the diode D1 and the input end of the intrinsically safe voltage processing circuit in a branching mode, the resistor Rfb2 is connected with a resistor Rfb0 and is connected with a pin 2 FB of the U1, the resistor Rfb0 is grounded through a digital potentiometer Rfb1, and Rfb1 is a digital potentiometer; the intrinsic safety voltage extender needs a single chip microcomputer to measure Vin, Vout and Vo and output control signals CTR1, CTR2, CTR3, CTR4, CTR5, CTR6 and CTR7 so as to judge and control the operation state of each circuit and the power consumption condition of a load;

the single chip microcomputer enables the switching power supply of the intrinsically safe voltage booster circuit to be started only once within a preset time interval by controlling the CTR3 and the CTR4, and if the starting is unsuccessful, the single chip microcomputer is started after the intrinsically safe voltage Vin at the input end of the intrinsically safe voltage extender is stabilized; the single chip microcomputer can control the output voltage value of the switching power supply through the CTR5, the CTR6 and the CTR7, and therefore the output voltage range of the intrinsically safe voltage extender can be adjusted in voltage level according to the load power consumption condition.

Technical Field

The invention relates to an intrinsically safe voltage relay extension device, in particular to an intrinsically safe voltage relay extension device which is composed of an intrinsically safe power supply, an intrinsically safe voltage extender and a transmission cable under an explosive environment.

Background

In a coal mine safety monitoring system, an intrinsic safety power supply is important equipment, wherein 18V intrinsic safety voltage is relatively universal intrinsic safety power supply output voltage. After a voltage of 18V is transmitted for 3km over a long distance, if the load at the tail end reaches 300mA, the voltage drop on the transmission cable may reach more than 12V, so that the voltage at the tail end of the 3km is less than 6V, and the voltage value of 6V is not enough to ensure that the load equipment of a sensor type works normally. Therefore, it is necessary to take measures to reduce the effect of voltage drop on the transmission cable, so that after the 18V intrinsic safety voltage is transmitted over a long distance, the end of the bus has enough voltage value to maintain the normal operation of the load equipment at the position.

The general solution is: 1. an intrinsically safe power supply with higher output voltage is researched and developed, such as a 24V intrinsically safe power supply; 2. the resistance value of the cable per kilometer is reduced; 3. the length of the cable transmitted by the intrinsic safety power supply is shortened. Type 2 is often used, but results in thick cables, which not only increases the cost but also increases the difficulty of installation and use. There are many options for the method 3, but the installation of the load device is basically completed by increasing the number of power supply sources. The method 1 is not few, and has the defect that 24V intrinsic safety power supply is usually combined with non-intrinsic safety power supply, and the non-intrinsic safety power supply usually needs to be connected with 127V or 660V alternating voltage, so the use flexibility is poor. And the output current of the 24V intrinsic safety power supply is generally small, and the quantity of the load equipment which can be carried can not meet the coal mine production requirement.

The invention aims to overcome the defect of remote transmission of intrinsic safety voltage in the prior art, provides a device for prolonging the power supply distance when an intrinsic safety power supply supplies power through a transmission cable, can be applied to intrinsic safety circuits in any occasions under explosive environments such as coal mines, non-coal mines, petrochemical industry and the like, and relates to the situation that after the intrinsic safety voltage is transmitted for several kilometers through the transmission cable, the voltage at the tail end of the transmission cable is seriously insufficient due to large influence of voltage drop on the transmission cable, so that electric equipment connected to the tail end of the transmission cable cannot reliably operate.

However, the purpose of increasing the intrinsically safe voltage is not necessarily achieved by connecting the output end of the intrinsically safe power supply to the switching power supply through a cable to boost the voltage. According to the relevant national standard requirements, the intrinsic safety power supply must have overcurrent protection and overvoltage protection, and the output spark energy of the intrinsic safety power supply must pass a spark test. If the intrinsically safe power supply output is connected to a long cable (e.g., 1 to 2 km long) and then connected to a switching power supply, the following two situations may occur:

1. the starting current of the switching power supply is usually large, and at the starting moment, the starting impact current of the switching power supply is likely to be larger than the overcurrent protection value of the intrinsic safety power supply, so that the intrinsic safety power supply can start overcurrent protection. The delay of the overcurrent protection is typically less than 1 second, but is generally not very short. If the overcurrent protection delay is kept for a short time interval, the spark energy may not be discharged sufficiently, so that the spark energy is accumulated continuously, and the requirement of intrinsic safety is difficult to meet. Moreover, the intrinsic safety circuit is difficult to allow larger capacitance and inductance, so if the output end of the intrinsic safety power supply has overcurrent protection delay of hundreds of milliseconds, the load powered by the intrinsic safety power supply usually loses power unless the load has a backup battery;

2. the cable and the switch power supply are both provided with inductors, strong spark energy can be generated when the current in the inductors is switched on and off, the spark performance of the intrinsic safety power supply can be greatly influenced, and the intrinsic safety power supply is more likely to pass the intrinsic safety spark test when the inductance in the circuit is larger.

Therefore, in the connection mode of "intrinsically safe power supply + a long-distance cable (e.g. 1 to 2 km long) + switching power supply", a special technical solution is required if the start-up is smooth and the intrinsically safe voltage is improved.

Disclosure of Invention

The invention aims to solve the problems that when an intrinsic safety power supply is transmitted for a long distance through a transmission cable and the loading capacity of the intrinsic safety power supply is enhanced by improving the voltage, the switch power supply is easy to generate overcurrent protection due to large starting current of the switch power supply, and the inductance of the switch power supply and the cable can influence the intrinsic safety spark performance. Besides two necessary modules of overvoltage protection and overcurrent protection, the intrinsic safety power supply also needs to be added with two special functional modules: the inductive pulse sensitive detection module and the times accumulation counting time delay module; the input voltage and the output voltage of the intrinsically safe voltage extender are intrinsically safe voltages, and have an online power supply mode and a standby power supply mode, and the output voltage range (all intrinsically safe voltages) of the intrinsically safe voltage extender can be adjusted and changed according to the voltage level of the load power consumption condition, such as the output voltage levels which are relatively universal like 24V, 18V and 15V, and the specific voltage range level under special requirements (due to the particularity of the intrinsically safe power supply, the intrinsically safe power supply generally only has one output voltage range which cannot be changed).

The intrinsic safety voltage relay prolonging device provided by the invention adopts the following technical scheme:

an intrinsically safe voltage relay extension device comprises an intrinsically safe power supply and a non-intrinsically safe power supply connected with the input end of the intrinsically safe power supply, wherein intrinsically safe voltage output by the intrinsically safe power supply provides input voltage for an intrinsically safe voltage extender through a first transmission cable, and intrinsically safe voltage output by the intrinsically safe voltage extender provides power for a second transmission cable and a sensor type load;

the method is characterized in that:

the intrinsically safe power supply comprises an inductive pulse sensitive detection module and a frequency accumulation and counting time delay module which are sequentially connected in series;

this ampere of voltage extender is connected in parallel by the reserve power supply circuit of this ampere of voltage, reserve power supply output switch and the online power supply circuit of this ampere of voltage that establish ties in proper order and constitutes, this ampere of voltage online power supply circuit with the reserve power supply circuit of this ampere of voltage two's input port be connected and with this ampere of voltage extender's input Vin is connected, reserve power supply output switch output with this ampere of voltage online power supply circuit output is connected and with this ampere of voltage extender's output Vout is connected, this ampere of voltage reserve power supply circuit comprises this ampere of voltage-divider circuit and this ampere of voltage processing circuit that establish ties in proper order, its output with reserve power supply output switch connects.

The non-intrinsic safety power supply outputs non-intrinsic safety voltage after being powered by 127-660V, the intrinsic safety voltage output by the intrinsic safety power supply is Vs, the intrinsic safety voltage value at the input end of the intrinsic safety voltage extender is Vin, the intrinsic safety voltage at the output end of the intrinsic safety voltage extender is Vout, and the non-intrinsic safety power supply is connected with a second transmission cable and a sensor type load.

The intrinsic safety power supply comprises an intrinsic safety power supply essential function module (such as an overvoltage protection module and an overcurrent protection module), and further comprises an inductance pulse sensitive detection module and a time accumulation counting time delay module which are sequentially connected in series.

The inductive pulse sensitive detection module comprises a directional coupler PWU1, a resistor PWR1, a resistor PWR2, a resistor PWR3, a resistor PWR4, an N-channel field effect transistor PWQ1, a capacitor PWC1, an inductor PWL1 and a high-speed Schmitt trigger PWU2, wherein the directional coupler is connected with the grid electrode of the field effect transistor PWQ1 through a resistor PWR1, the grid electrode of the field effect transistor PWQ1 is grounded through the resistor PWR2 and is connected with +5V through a resistor PWR4, the source electrode of the field effect transistor PWQ1 is grounded, the drain electrode of the field effect transistor PWQ1 is connected with +5V voltage through a resistor PWR3, the drain electrode of the field effect transistor PWQ1 is connected with a pin 1 of the high-speed Schmitt trigger PWU2 through an inductor PWL1, the capacitor PWC1 is connected with the drain electrode of the field effect transistor PWQ1 and the drain electrode PWU2, and the high-speed Schmitt trigger PWU2 adjusts the waveform to be output to a digital signal after the number of the number indicating the number of the.

The number accumulation counting time delay module is realized by programming of a single chip microcomputer and comprises three timers and a number accumulator.

The intrinsic safety voltage extender is composed of an intrinsic safety voltage circuit, an intrinsic safety voltage processing circuit, a standby power supply output switch and an intrinsic safety voltage online power supply circuit which are sequentially connected in series, wherein the intrinsic safety voltage circuit and the intrinsic safety voltage processing circuit are combined to form the intrinsic safety voltage standby power supply circuit, input ports of the intrinsic safety voltage online power supply circuit and the intrinsic safety voltage standby power supply circuit are connected and are connected with an input end Vin of the intrinsic safety voltage extender, an output end Vo of the intrinsic safety voltage standby power supply circuit is connected with an input end of the standby power supply output switch, and an output end of the standby power supply output switch is connected with an output end of the intrinsic safety voltage online power supply circuit and is connected with an output end Vout of the intrinsic safety voltage extender.

The Vin is intrinsic safety voltage, and the voltage range of the Vin is greater than or equal to 10V and less than or equal to 24V;

the Vout is also an intrinsic safety voltage, and has a voltage range greater than 10V and less than or equal to 50V, a default voltage level of 18 + -0.9V, and also can have voltage range levels of 24 + -1.2V and 15V + -0.75V which are relatively common, and a specific voltage range level under special requirements. For example, when Vin and Vo are unstable and jump out after the intrinsically safe voltage backup power supply circuit is started, Vout is adjusted to be in a voltage range of 15V ± 0.75V.

The standby power supply output switch is used for switching on or off Vo and Vout, and comprises a P-channel field effect transistor Q4, wherein the source electrode of the P-channel field effect transistor Q4 is connected with Vo, the drain electrode of the P-channel field effect transistor Q2 is connected with the anode of a diode D2, the grid electrode of the P-channel field effect transistor D2 is connected with a singlechip output control signal CTR2, and the cathode of the diode D2 and the drain electrode of Q.

The intrinsic safety voltage online power supply circuit comprises a P-channel field effect transistor Q3, wherein the source electrode of the P-channel field effect transistor Q3 is connected with Vin, the drain electrode of the P-channel field effect transistor Q3 is connected with the cathode of a diode D2 and Vout, and the grid electrode of the P-channel field effect transistor Q3 is connected with a single chip microcomputer output control signal CTR 1.

The intrinsically safe voltage standby power supply circuit comprises an intrinsically safe voltage stabilizing circuit and an intrinsically safe voltage processing circuit, wherein the input end of the intrinsically safe voltage stabilizing circuit is connected with Vin, the output end (the output voltage is Vox) of the intrinsically safe voltage stabilizing circuit is connected with the input end of the intrinsically safe voltage processing circuit, the output end of the intrinsically safe voltage processing circuit is connected with the input end of a standby power supply output switch, voltage measurement and control signals of the intrinsically safe voltage stabilizing circuit are provided by a single chip microcomputer, the output end of the intrinsically safe voltage standby power supply circuit is also the output end of the intrinsically safe voltage processing circuit, and the output voltage of the intrinsically safe voltage standby power supply circuit is.

The intrinsic safety voltage-boosting circuit is used for boosting the accessed Vin, an LM5022 chip U1 is selected, and an element connected with the U1 is an LM5022 standard configuration circuit. The field effect transistor Q1 is a switching transistor in the LM5022 standard configuration circuit, the field effect transistor Q2 is a switching transistor for controlling the U1 to start or stop working, and the field effect transistor Q5 is a switching transistor for controlling whether Vin is connected to the booster circuit or not. Rfb1 is a digital potentiometer, and controls the output voltage of the switching booster circuit by CTR5, CTR6 and CTR7, and also adjusts the voltage value of Vo.

The intrinsic safety voltage processing circuit is used for converting the boosted voltage output by the intrinsic safety voltage processing circuit into intrinsic safety voltage Vo, and comprises an overcurrent protection circuit and an overvoltage protection circuit; the overcurrent protection circuit is used for ensuring that overcurrent protection is executed when the output current of the voltage output port exceeds a set value; the overvoltage protection circuit is used for executing overvoltage protection when the output voltage of the voltage output port exceeds a set value.

The technical scheme of the invention has the following characteristics:

(1) because the starting impact current is usually large when the switching power supply is started, the peak of the starting current often causes the over-current protection of the intrinsically safe power supply, so that the following situations may occur:

starting the switch power supply for increasing voltage → generating overcurrent protection for the intrinsic safety power supply → low voltage at the output end of the intrinsic safety power supply with a duration of hundreds of milliseconds → the switch power supply is started to be too low → the output end of the intrinsic safety power supply recovers to normal voltage → the switch power supply is started again → the cycle is repeated.

The invention solves the problem of large starting current of the switching power supply by the following measures:

i. the intrinsic safety power supply with a large overcurrent protection value is adopted, the overcurrent protection value is 1A, and the starting current peak value of the selected switching power supply is below 1A, so that overcurrent protection of the intrinsic safety power supply cannot be caused during starting;

selecting a switch boosting power supply which has small starting current, has a soft starting function and can set soft starting time;

and iii, a frequency accumulation counting time delay module is added to the intrinsic safety power supply, so that the problem caused by large starting impact current when the switching power supply is started can be effectively avoided:

if the starting current of the switching power supply exceeds the overcurrent protection value of the intrinsic safety power supply when the switching power supply is started, the intrinsic safety power supply usually immediately executes overcurrent protection action, but when overcurrent protection occurs for the first time, the delay interval of the output end of the intrinsic safety power supply is set as short delay, and the second and later overcurrent protection delay is changed into long delay. When the first overcurrent protection is carried out within a preset time interval, such as 30 seconds, because the first overcurrent protection is carried out, no factors such as energy accumulation exist before the first overcurrent protection, the spark performance is not easily influenced even if the delay is short, and the spark energy can be released to a certain extent to reduce the spark energy accumulation when the delay is a certain delay. Under the condition that the short delay time is appropriate, the energy stored by the inductance and the capacitance of the cable and the switching power supply is not completely released, so that the switching power supply is not easily powered off in the starting process; however, if the second overcurrent protection occurs, a long time delay must be performed to release the energy stored in the inductors and capacitors.

The number accumulation takes 10 seconds as a period when the number accumulation is started, if overcurrent protection is only performed once within 10 seconds, the 10-second timer and the number accumulator are reset after 10 seconds, and if overcurrent protection is performed again later, the number accumulation is counted according to the first start; if overcurrent protection occurs twice or more within 10 seconds, the 10-second delay increases by 5 seconds from the second time to 15 seconds for each occurrence of overcurrent protection. I.e. three times overcurrent protection takes place, the cycle becomes 20 seconds, and so on for the fourth time. The number accumulation and timing rule is used for more reliably ensuring that the spark energy can be fully released when overcurrent protection occurs for a plurality of times, and further ensuring that the intrinsic safety power supply can safely and stably operate.

(2) Because the switch boosting power supply and the cable both have certain inductance, if the current in the inductance is switched on and off frequently, high-frequency pulses occur, and spark energy accumulation is possibly caused to influence the spark performance of the intrinsically safe circuit.

Therefore, the invention adopts the following measures to deal with the problem that the inductance influences the intrinsic safety spark performance:

i. an inductance pulse sensitive detection module is added in the intrinsic safety power supply;

the inductance pulse sensitive detection module can very quickly detect high-frequency pulses appearing at the output end of the intrinsic safety power supply, so that the intrinsic safety power supply can timely execute overcurrent protection, and the current and voltage of the output end are turned off and short delay or long delay is carried out, so that energy accumulation caused by the inductance is released, the spark energy is reduced, and the spark test requirement of the intrinsic safety is met.

Avoiding frequent startup of the switching power supply. Frequent starting of the switching power supply easily causes repeated on-off of current in the whole loop, so that spark energy is accumulated; and when the voltage is unstable, the starting of the switching power supply can cause the working voltage to fluctuate more, and even the whole device is in a breakdown state. In order to prevent this, the invention proposes the following countermeasures:

a. it is only activated once in a predetermined time interval.

In the standby power supply mode of the intrinsic safety voltage extender, a preset time interval is adopted, if the preset time interval is 1 minute, the switching power supply is started only once in the time interval, and if the starting is unsuccessful, the switching power supply is started after the intrinsic safety voltage Vin at the input end of the intrinsic safety voltage extender is stabilized.

b. The method of not supplying power to the load firstly is adopted.

In the standby power supply mode of the intrinsic safety voltage extender, the working mode that the load is not supplied with power firstly, but the switching power supply is started firstly, the boosting is waited to be completed, and the intrinsic safety voltage Vo output by the standby power supply circuit of the intrinsic safety voltage extender is stabilized and then the load is switched on is adopted.

c. Digital control is used to achieve Vout slow start-up.

In the standby power supply mode of the intrinsic safety voltage extender, when the intrinsic safety voltage Vo output by the standby power supply circuit of the intrinsic safety voltage extender starts to supply power to a load, a digital control mode is adopted to realize a slow start rising mode, such as rising from 10V to 18V within 1 second. On one hand, Vout adopts a slow start rising mode, so that the problems that the Vin is rapidly reduced, even the lowest voltage of the Vin is lower than the lowest limit of the input voltage of the switching power supply, the switching power supply cannot normally boost and the like due to sudden rise of load current caused by sudden change of voltage on the load can be avoided; on the other hand, when Vo is output to Vout, the on-line power supply mode is not completely disconnected, and abnormal power supply is prevented.

d. The intrinsic safety voltage extender adopts a variable output voltage range mode.

In the standby power supply mode of the intrinsically safe voltage extender, because a digital control mode is adopted to realize a slow start rising mode, if Vin and Vout are unstable and jump randomly in the voltage rising process, Vout is regulated to be in the voltage range of 15V +/-0.75V. The reduction of the output voltage Vout can reduce the power consumption of the load, and the reduction amplitude of Vin is smaller than that of Vout =18V, so that the standby power supply circuit of the intrinsically safe voltage extender can work more stably to a certain extent.

(3) The intrinsic safety voltage extender adopts an online power supply mode and a standby power supply mode, and preferentially uses the online power supply mode, so that the influence of the situations (1) and (2) on the performance of the whole device is further avoided.

The measures can effectively detect the high-frequency pulse of the inductor, effectively avoid the problem of frequent starting of the switching power supply, reduce spark energy accumulation, ensure the safety of the intrinsic safety circuit, and simultaneously increase the reliability and stability of the whole device, thereby ensuring the realization of the long-distance transmission of the intrinsic safety voltage.

Drawings

FIG. 1 is a schematic block diagram of an intrinsically safe voltage relay extension arrangement of the present invention;

FIG. 2 is a block diagram of the schematic flow of an inductive pulse sensitive detection module and a number accumulation count delay module within the intrinsically safe power supply of FIG. 1;

FIG. 3 is a schematic diagram of a directional coupler in the inductive pulse sensitive detection module of FIG. 1;

FIG. 4 is a circuit schematic of the inductive pulse sensitive detection module of FIG. 1;

FIG. 5 is a functional block diagram of the intrinsically safe voltage extender circuit of FIG. 1;

FIG. 6 is a control logic diagram of the intrinsically safe voltage extender of FIG. 5;

fig. 7 is a circuit schematic diagram of the intrinsically safe voltage handling circuit of fig. 1.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the intrinsically safe voltage relay extender provided by the present invention includes a non-intrinsically safe power supply, an intrinsically safe power supply, a first transmission cable, and an intrinsically safe voltage extender, wherein the non-intrinsically safe power supply is connected to an input end of the intrinsically safe power supply, an output end of the intrinsically safe power supply is connected to the first transmission cable, a tail end of the first transmission cable is connected to an input end of the intrinsically safe voltage extender, and an output end of the intrinsically safe voltage extender is connected to a start end of a second transmission cable. The intrinsic safety power supply not only comprises necessary functional modules (overvoltage protection and overcurrent protection), but also comprises two special functional modules (an inductance pulse sensitive detection module and a time accumulation counting time delay module). The input ports of an intrinsic safety voltage online power supply circuit and an intrinsic safety voltage standby power supply circuit in the intrinsic safety voltage extender are connected and connected to the tail end of the first transmission cable, the output end of the intrinsic safety voltage standby power supply circuit is connected with the input end of the standby power supply output switch, the output end of the standby power supply output switch is connected with the output end of the intrinsic safety voltage online power supply circuit and connected to the starting end of the second transmission cable, and the second transmission cable is connected with the sensor type load. The standby power supply circuit for the intrinsic safety voltage comprises an intrinsic safety voltage-boosting circuit and an intrinsic safety voltage processing circuit, wherein the input end of the intrinsic safety voltage-boosting circuit is the input end of the standby power supply circuit for the intrinsic safety voltage, the output end of the standby power supply circuit for the intrinsic safety voltage is connected with the input end of the intrinsic safety voltage processing circuit, and the output end of the standby power supply circuit for the intrinsic safety voltage is the output end of the standby power supply circuit for the intrinsic safety voltage.

The non-intrinsic safety power supply outputs non-intrinsic safety voltage after being powered by 127-660V and is connected to the input end of the intrinsic safety power supply, the output end of the intrinsic safety power supply outputs intrinsic safety voltage Vs, the intrinsic safety voltage Vs is connected to the input end of the intrinsic safety voltage extender through a first transmission cable, and the voltage value of the intrinsic safety power supply is Vin (still intrinsic safety voltage). Since there will be a voltage drop over the first transmission cable (especially if the cable is relatively long), Vin is typically less than Vs. The intrinsic safety voltage output by the output end of the intrinsic safety voltage extender is Vout, wherein the voltage of the output end of the intrinsic safety voltage standby power supply circuit is the intrinsic safety voltage Vo, and the voltage of the input end of the intrinsic safety voltage processing circuit is Vox (Vox is not the intrinsic safety voltage).

As shown in fig. 2, the voltage Vs at the output end of the intrinsically safe power supply is connected with the inductive pulse sensitive detection module, the output signal of the inductive pulse sensitive detection module is connected with a frequency accumulator and a timer 2 in the single chip microcomputer, the frequency of the frequency accumulator is the first time, the first time is output to the timer 1 and is connected with the execution overcurrent protection module, the timer 1 outputs short delay, and the execution overcurrent protection module outputs a signal to the timer 2 after the delay is finished; if the number of times of accumulation of the accumulator is larger than or equal to the second time, the accumulated number of times of accumulation is output to the timer 3 and is connected with the execution overcurrent protection module, the timer 3 outputs long delay, and the execution overcurrent protection module can also output a signal to the timer 2 after the delay is finished. The timer 2 outputs a reset signal to the times accumulator, the timer 3 and the timer 1 when the timing is finished.

FIG. 3 shows a directional coupler type selected for use in the inductive pulse sensitive detection module, including both low pass L-C branch type couplers and parallel line type couplers.

As shown in fig. 4, the inductor pulse is coupled and isolated by the directional coupler PWU1 and then transmitted to the gate of the fet PWQ1 through the resistor PWR1, the drain of the fet PWQ1 outputs the pulse with the attenuated amplitude, and after being filtered by the capacitor PWC1 and the inductor PWL1, the pulse with the lower frequency is input to pin 1 of the schmitt trigger PWU2, and after being waveform-shaped by the schmitt trigger PWU2, the pulse outputs a digital signal to the time accumulation and counting delay module through pin 2.

As shown in fig. 5, the intrinsic safety voltage Vin is connected to the source of the fet Q3 and the anode of the diode D3, the gate of the fet Q3 is connected to the CTR1, Vout is connected to the drain of the fet Q3 and the cathode of the diode D2, the source of the fet Q4 is connected to the intrinsic safety voltage Vo output by the intrinsic safety voltage processing circuit, and the D of the fet Q4 is connected to the anode of the diode D2. The field effect transistor Q3 is an intrinsic safety voltage online power supply circuit; the field effect transistor Q4 and the diode D2 constitute a standby power supply output switch.

The intrinsic safety voltage-stabilizing circuit comprises a configuration circuit of a diode D3, a field-effect tube Q5, a field-effect tube Q2, a voltage-transformation controller U1 and a configuration circuit of a U1, wherein the cathode of a diode D3 is connected with the source electrode of the field-effect tube Q5, and the anode of a diode D3 is connected with Vin; the drain electrode of the field effect transistor Q5 is connected with a pin VIN 1 of U1, and the grid electrode is connected with CTR 3; a resistor Rt and capacitors Cinx and Cin are connected in series between a pin 9 RT and a pin 1 VIN of the U1; a resistor Ruv2 is connected between a pin 7 UVLO and a pin 1 VIN of the U1, and the pin 7 UVLO is grounded through a resistor Ruv 1; the drain electrode of the field effect transistor Q2 is connected with a pin 7 UVLO of the U1, the source electrode of the field effect transistor Q2 is grounded, and the gate electrode of the field effect transistor Q2 is connected with the CTR4 and is grounded through a resistor Rx 1; pin 10 SS of U1 is grounded via capacitor Css; a capacitor Ccomp2 is connected between the 3 pin COMP and the 2 pin FB of the U1, and a resistor Rcomp and a capacitor Ccomp which are mutually connected in series are connected between the two ends of the capacitor Ccomp2 in parallel; a pin OUT 5 of the U1 is connected with a grid G of a field effect transistor Q1, and an inductor L1 is connected between a pin Vin 1 of the U1 and a drain D of the field effect transistor Q1; a resistor Rs1 and a resistor Rs2 are connected in series between an 8-pin CS of the U1 and a source S of the field-effect tube Q1, the source S of the field-effect tube Q1 is grounded through a resistor Rsns, and a capacitor Ccs connected with GND is connected between a resistor Rs1 and a resistor Rs2 in a branching manner; the 6 pin GND of U1 is grounded, and the 4 pin VCC of U1 is grounded through capacitor Cbyp. A diode D1 is connected between the drain D of the field effect transistor Q1 and the input end of the intrinsically safe voltage processing circuit, a capacitor Cout, a capacitor C11 and a resistor Rfb2 are connected between the diode D1 and the input end of the intrinsically safe voltage processing circuit (the Net Label at the position is Vox) in a branch manner, the capacitor Cout and the capacitor C11 are grounded, the resistor Rfb2 and the resistor Rfb0 are connected with a pin FB2 of the U1, and the resistor Rfb0 is grounded through a digital potentiometer Rfb 1.

Referring to fig. 6, the single chip of the intrinsically safe voltage extender needs to measure Vin, Vout and Vo, output control signals CTR1, CTR2, CTR3, CTR4, CTR5, CTR6 and CTR7, and start and output a 30-second and 1-minute timer to judge the operation state of the circuits of each part of the intrinsically safe voltage extender and the power consumption condition of the load.

As shown in fig. 7, the intrinsically safe voltage processing circuit includes a transistor U1, a transistor U2, and a field effect transistor U3, where U1 and U2 are PNP power transistors, ports Vin of U1 and U2 correspond to an emitter E, ports Vout of U1 and U2 correspond to a collector C, ports ADJ of U1 and U2 correspond to a base B, a port Vin of a field effect transistor U3 corresponds to a drain, a port Vout of the field effect transistor U3 corresponds to a source S, and a port ADJ of the field effect transistor U3 corresponds to a gate G. A port Vin of the triode U1 is connected with an output end Vox of the intrinsic safety voltage-stabilizing circuit, a port Vout of the U1 is connected with a port Vin of the U2, a port ADJ of the U1 is connected with a collector of the Darlington triode BG1 through a resistor R2, a base of the Darlington triode BG1 is connected with the port Vin of the triode U1 through a resistor R1, an emitter of the Darlington triode BG1 is respectively connected with a capacitor C1 and a resistor R3, the capacitor C1 is connected with the port Vout of the triode U1, and the resistor R3 is grounded GND. A port Vout of the triode U2 is connected with a port Vin of the field effect transistor U3, a port ADJ of the triode U2 is connected with a collector of a Darlington triode BG2 through a resistor R5, a base of the Darlington triode BG2 is connected with a port Vin of the triode U2 through a resistor R4, an emitter of the Darlington triode BG2 is respectively connected with a capacitor C2 and a resistor R6, a capacitor C2 is connected with a port Vout of the triode U2, and the resistor R6 is grounded GND.

A port Vout of the field effect tube U3 is connected with a port Vin of the triode U1 through a resistor R15 and a diode D6, and a port ADJ of the field effect tube U3 is respectively connected with a resistor R7, a resistor R8, a collector of the triode BG5 and a collector of the triode BG 6. The resistor R7 is connected with the port Vin of the field effect transistor U3 through the capacitor C3. The resistor R8 is respectively connected with the collector electrodes of a constant current diode DH and a triode BG3, and the constant current diode DH is connected with a port Vin of a triode U1; an emitter of the triode BG3 is grounded to GND, a base electrode of the triode BG3 is connected with an emitter of the triode D2 through a resistor R11, the base electrode and a collector of the triode D2 are both grounded to GND through a resistor R14, and an emitter of the triode D2 is connected with a port Vout of a field-effect tube U3 through a capacitor C4, a resistor R10 and a resistor R15 which are connected in series; the collector of the triode BG3 is connected with the collector of the triode BG4, the emitter of the triode BG4 is grounded to GND, the base of the triode BG4 is connected with the emitter of the triode D3 through a resistor R13, the base and the collector of the triode D3 are grounded to GND, and the emitter of the triode D3 is connected with the port Vout of the field effect tube U3 through a capacitor C5, a resistor R12 and a resistor R15 which are connected in series. An emitter of the transistor BG5 is connected with a port Vout of a field effect transistor U3 through a resistor R15, a base of the transistor BG5 is respectively connected with a potentiometer W1 and a resistor R16, a potentiometer W1 is connected with the port Vout of the field effect transistor U3, and the resistor R16 is grounded GND. An emitter of the transistor BG6 is connected with a port Vout of a field effect transistor U3 through a resistor R15, a base of the transistor BG6 is respectively connected with a potentiometer W2 and a resistor R17, a potentiometer W2 is connected with the port Vout of the field effect transistor U3, and the resistor R17 is grounded GND.

The collector of the triode BG3 is connected with the collector of the triode BG7 through a resistor R9 and a diode D4 which are connected in series, the collector of the triode BG7 is further connected with a capacitor C6, the capacitor C6 is respectively connected with a potentiometer W3, a resistor R18, a resistor R19 and a resistor R20, the potentiometer W3 is connected with a port Vout of a field-effect tube U3 through the resistor R21 and the resistor R15, and the resistor R18, the resistor R19 and the resistor R20 are all grounded GND. The base electrode of the triode BG7 is connected with the port Vout of the field effect transistor U3 through a resistor R21 and a resistor R15, the emitter electrode of the triode BG7 is respectively connected with a diode D5 and a resistor R22, the diode D5 is grounded GND, and the resistor R22 is connected with the port Vout of the field effect transistor U3 through a resistor R15.

A port Vout of the field effect transistor U3 is connected to a diode D9, a diode D10, and a resistor R27 through a resistor R15, respectively, a diode D9 is connected to GND through a diode D7 and a resistor R23, a diode D10 is connected to GND through a diode D8 and a resistor R25, and a resistor R27 is connected to GND through a capacitor C9. The resistor R24 and the capacitor C7 which are mutually connected in series are connected in parallel at two ends of the resistor R23, and the resistor R26 and the capacitor C8 which are mutually connected in series are connected in parallel at two ends of the resistor R25.

The base electrode of the Darlington transistor BG1 is connected with the A pole of the thyristor SCR1, the K pole of the thyristor SCR1 is grounded GND, and the J pole of the thyristor SCR1 is connected between the resistor R24 and the capacitor C7. The base electrode of the Darlington transistor BG2 is connected with the A pole of the thyristor SCR2, the K pole of the thyristor SCR2 is grounded GND, and the J pole of the thyristor SCR2 is connected between the resistor R26 and the capacitor C8.

The intrinsic safety voltage relay prolonging device provided by the invention has the following specific working process:

as shown in fig. 1, the non-intrinsically safe power supply outputs a non-intrinsically safe voltage, and the intrinsically safe voltage Vs is output through the intrinsically safe power supply, wherein the intrinsically safe voltage value of Vs is changed into Vin after long-distance transmission through a first transmission cable, and the Vin supplies power to the intrinsically safe voltage extender, which outputs the intrinsically safe voltage Vout in an online power supply mode or a standby power supply mode to supply power to a load connected to a second transmission cable through a second transmission cable.

As shown in fig. 2, in the intrinsically safe power supply, if an inductive pulse appears on the voltage Vs at the output end of the intrinsically safe power supply, the inductive pulse becomes a square wave signal readable by the single chip microcomputer after isolated coupling of the inductive pulse sensitive detection module and filter shaping of the pulse, the single chip microcomputer starts a frequency accumulator and a timer 2 after receiving the signal, if the frequency in the frequency accumulator is the first time, the timer 1 is started and immediately executes overcurrent protection, the timer 1 is short-delay, after the delay of the timer 1 is over, the overcurrent protection outputs a signal to the timer 2, and at this time, the delay of the timer 2 is 10 seconds (starting timing from the start of the timer 2). If no second overcurrent protection occurs within 10 seconds, the timer 2 outputs a reset signal after 10 seconds are ended, so that the timer 3 and the frequency accumulator are cleared. When the inductive pulse appears for the second time on Vs within 10 seconds, the inductive pulse is input to a time accumulator after pulse filtering and shaping, the time accumulator accumulates for the second time, then a timer 3 is started and overcurrent protection is immediately executed, the timer 3 is long-delay, and after the delay of the timer 3 is finished, the overcurrent protection also outputs a signal to the timer 2 to prolong the delay of the timer 2 by 5 seconds.

If the second and more than second overcurrent protection occurs within 10 seconds, the delay of the timer 2 is prolonged by 5 seconds every time the overcurrent protection is executed. Namely, overcurrent protection occurs twice, the time delay of the timer 2 becomes 15 seconds; if three times of overcurrent protection occurs, the delay of the timer 2 becomes 20 seconds, and so on. After the delay of timer 2 is over, if an inductive pulse appears on Vs, timer 2 also starts timing from zero as the first time it starts counting on the times accumulator.

As shown in fig. 5 and 6, in the intrinsically safe voltage extender, the fet Q3 is turned on by default, the fet Q4 is turned off, Vin is output through the fet Q3, and its voltage is Vout, which is the online power supply mode. The intrinsic safety voltage processing circuit and the intrinsic safety voltage processing circuit are together called an intrinsic safety voltage standby power supply circuit, and if Vin outputs intrinsic safety voltage Vout through the intrinsic safety voltage standby power supply circuit and the standby power supply output switch, and the field effect transistor Q3 is turned off, the standby power supply mode is set.

If Vin is larger than or equal to 14V, Vout is larger than or equal to 14V, and the measured values of the Vin and the Vout are stable, keeping Q3 on; otherwise, if Vin is more than or equal to 10V and less than 14V and Vout is more than or equal to 10V and less than or equal to 14V, and the measured values of the two are stable and do not jump randomly, the single chip microcomputer controls the CTR3 to output a low level and enables the CTR4 to output the low level, and the intrinsic safety voltage boosting circuit is started.

In the intrinsic safety voltage-boosting circuit, the voltage range of the intrinsic safety voltage Vin is set to be 10-24V. U1 realizes this ampere of voltage transformation through the break-make of control field effect transistor Q1 and inductance L, diode D1 and the combined action of other components. The single chip microcomputer can adjust the output voltage Vox of the intrinsic safety voltage processing circuit by controlling the resistances of the CTR5, the CTR6 and the CTR7 to adjust the resistance of the digital potentiometer Rfb1, so that the output voltage Vo of the intrinsic safety voltage processing circuit can realize a slow start rising mode from 10V to 18V, and the slow start rising time can be preset, for example, the slow start rising time is set to be from 10V to 18V within 1 second. The voltage fluctuation range of the intrinsic safety voltage Vout during stable operation is default to 18 + -0.9V.

In the intrinsically safe voltage extender, firstly, the normal operation of the single chip microcomputer needs to be ensured, then the single chip microcomputer measures Vin and Vout, if the measured values of the Vin and the Vout are stable and do not jump out of order and the measured values of the Vin and the Vout are both more than or equal to 14V, the online power supply mode is continuously kept, namely the low level of CTR1 is kept to enable Q3 to be conducted, and the high level of CTR2, the high level of CTR3, the high level of CTR4 and the high level of CTR7 are kept. If the measured values of Vin and Vout are stable and do not jump for 1 minute, and the measured values of the Vin and the Vout are between 10 and 14V, the CTR3 is firstly made to be at a low level, the Q5 is made to be turned on, then the CTR4 is made to be at a low level, the Q2 is made to be turned off, the intrinsic safety voltage-changing circuit and the intrinsic safety voltage processing circuit are started, and Vo =18.3V is enabled (Vout is approximately equal to Vo-0.3V, 0.3V is the voltage drop of the diode D2, and the voltage drop of the field effect transistor Q2 is almost 0. If the measured values of Vin and Vo are stable and do not jump over 30 seconds and the measured value of Vo is 18.3 +/-0.9V, the CTR3 and the CTR4 are continuously kept at a low level, the CTR1 is at a high level, the CTR2 is at a low level, the Q3 is cut off, the Q4 is turned on, the CTR5, the CTR6 and the CTR7 are controlled to adjust the resistance value of the digital potentiometer Rfb1, the Vo is increased from 10V to 18V within 1 second, whether the measured values of Vin and Vout are stable and do not jump over 1 second is monitored, and the time interval is 30 seconds. If the Vin and Vout are unstable and jumped, delaying for 30 seconds and monitoring the stable conditions of the Vin and Vout at the same time, and if the measured value is stable within the delay of 30 seconds, keeping the Vout in the range of 18V and monitoring the Vin, Vout and Vo circularly; if the measured value is unstable, regulating the Vout to be in a voltage range of 15V +/-0.75V, still monitoring whether the measured values of Vin and Vout are stable and do not jump, wherein the time interval is 30 seconds, if the measured values of Vin and Vout are stable, circularly monitoring Vin, Vout and Vo in the range of 15V +/-0.75V, if the measured values of Vin and Vout are still unstable and jump, delaying for 30 seconds and continuously monitoring the stable conditions of Vin and Vout, and if the measured values of Vin and Vout are indeed unstable and jump within the delay of 30 seconds, switching to an online power supply mode, closing a standby power supply mode, namely enabling the CTR1 to be low in level, the CTR2 high level, the CTR3 high level and the CTR4 high level, and then continuously measuring the Vin and Vout by the single chip microcomputer.

As shown in fig. 7, the intrinsically safe voltage processing circuit includes an overcurrent protection circuit and an overvoltage protection circuit. The overcurrent protection circuit is used for ensuring that overcurrent protection is executed when the output current of the voltage output port exceeds a set value. The overvoltage protection circuit is used for executing overvoltage protection when the output voltage of the voltage output port exceeds a set value.

The field-effect transistor U3, the resistor R15, the potentiometer W1, the potentiometer W2, the triode BG5 and the triode BG6 form an overcurrent protection circuit. When the voltage drop between the potentiometer W1 or the potentiometer W2 and the resistor R15 reaches the conduction of the triode BG5 or the triode BG6, the triode BG5 or the triode BG6 is conducted, so that the voltage of the control electrode of the field-effect tube U3 is reduced, the current passing through the field-effect tube U3 is reduced, and the overcurrent protection function is realized.

The overvoltage protection circuit comprises a triode U1, a triode U2, a Darlington triode BG1, a Darlington triode BG2, a thyristor SCR1, a thyristor SCR2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a capacitor C1, a capacitor C2, a capacitor C7, a capacitor C8, a diode D7, a diode D8, a diode D9 and a diode D10. Diode D7, diode D9 and triode U1, Darlington triode BG1, thyristor SCR1 are a group of overvoltage protection, and diode D8, diode D10 and triode U2, Darlington triode BG2, thyristor SCR2 are another group of overvoltage protection. When the output voltage exceeds 26V, the thyristor SCR1 or the thyristor SCR2 is switched on, and the triode U1 or the triode U2 is switched off, so that the overvoltage protection function is realized.

The energy suppression circuit comprises a constant current diode DH, a triode BG3, a triode BG4, a triode D2, a triode D3, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a capacitor C4 and a capacitor C5. The output voltage Vo is connected with the transistor BG3 and the transistor BG4 through the resistor R10, the capacitor C4, the resistor R12 and the capacitor C5. When the energy output by Vo is increased, the transistor BG3 or the transistor BG4 is conducted through the resistor R10, the capacitor C4 or the resistor R12 and the capacitor C5, so that the intrinsic safety output energy is reduced.

While the present invention has been described in terms of its functions and operations with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise functions and operations described above, and that the above-described embodiments are illustrative rather than restrictive, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined by the appended claims.