Intrinsic safety power supply protection system and control method thereof
By integrating current sensors, comparison circuits, microcontrollers and other components in the intrinsically safe power protection system, dynamic control of the output current is solved, and the problem of taking into account spark performance, hot plug performance and EMC performance in the existing technology is improved, and the reliability and stability of the equipment working underground in coal mines is improved.
Patent Information
- Application Number
- CN202510371672.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-20
AI Technical Summary
When used underground intrinsic safety power protection technology in coal mines, it is difficult to take into account spark performance, hot plug performance and EMC performance, resulting in poor user experience and abnormal equipment work, which may lead to the loss of critical data.
An intrinsically safe power protection system including current sensors, comparison circuits, microcontrollers, negative feedback control units, three-way selection circuits and temperature sensors is adopted. By collecting and analyzing current, temperature and interference signals in real time, dynamic limiting and controlling the output current is achieved, ensuring stable power supply during hot swapping and EMC interference.
It achieves improvements in spark performance, hot plug performance and EMC performance, ensuring reliable and stable operation of the equipment under harsh conditions, avoiding device restart and critical data loss.
Smart Images
Figure CN120185362A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of intrinsically safe power supply protection, and mainly relates to an intrinsically safe power supply protection system and its control method. Background Art
[0002] There will be combustible gases in the air in coal mines. When electrical equipment works in coal mines, if the electrical equipment needs to be directly exposed to the air containing combustible gases, certain means need to be adopted to avoid the sparks caused by short - circuit faults of the electrical equipment. Because when the energy of the spark exceeds a certain limit and there is a proper concentration of combustible gases nearby, an explosion may be triggered. At this time, it is necessary to perform intrinsically safe protection on the power supply of the electrical equipment in coal mines. The power supply after this intrinsically safe protection is the so - called intrinsically safe power supply. The intrinsically safe power supply can limit the energy accumulated by the short - circuit when a short - circuit fault occurs in the load equipment, so that the spark brought by the short - circuit is not enough to ignite the combustible gas, thus obtaining a kind of essential safety, which is also the origin of "intrinsically safe" in the name of "intrinsically safe power supply".
[0003] In the implementation of intrinsically safe power supplies, there are usually two methods. One is to use an inductor to measure the rate of change of current. When the current increases at a very fast speed, the voltage across the inductor will become very large. At this time, it is judged that a short - circuit fault has occurred based on this, and then a monostable flip - flop or a timing circuit similar to a monostable flip - flop is immediately used to trigger a power output cut - off of a fixed length. The other method is to use a resistor or a current sampling chip to collect the magnitude of the output current. When the current is greater than a certain fixed value, a monostable flip - flop or a timing circuit similar to a monostable flip - flop is also immediately used to trigger a power output cut - off of a fixed length. Both of these methods achieve the constraint of output energy by directly closing the control output switch device and then restoring the output after a fixed time duration. To avoid sparks caused by short - circuits. However, there are also significant drawbacks in this: The spark performance (the performance of timely shutting down in case of sparks that can cause explosion) is no longer the only criterion for evaluating the performance of intrinsically safe power supplies. There are also two other criteria that users highly value: hot pluggability and EMC performance. Hot pluggability means that as the number of load devices connected to the intrinsically safe power supply increases, multiple load devices such as sensors may be connected to one output of the intrinsically safe power supply, and these load devices are dynamically changing. It is possible to hot plug some devices while powered on without exceeding the total capacity of the intrinsically safe power supply. On the one hand, these devices generally use aviation plugs to connect to the output of the intrinsically safe power supply. During the hot plugging process, there may be a short contact between the live pins of the aviation plug and the power ground, which is similar to the occurrence of a short circuit phenomenon, thus triggering the protection shutdown of the intrinsically safe power supply. At this time, it is possible that other devices originally connected to this path may restart due to a short power outage, and the power outage and restart will cause devices such as sensors to be in the on state for one minute or even longer, unable to collect useful data, and users can hardly accept this phenomenon. On the other hand, there are capacitors of different sizes at the power supply inlet of the sensor device. If the capacitor is large, it will also cause a large current charging phenomenon similar to a short circuit when connecting to the intrinsically safe power supply, thus triggering the protection shutdown of the intrinsically safe power supply and causing other devices to have a power outage and restart. Both of these situations will lead to a decline in the user experience. The EMC performance refers to that when external high-speed and short-term interference signals are injected into the power supply circuit, the inductor or current sampling device may misjudge due to this interference. The electromagnetic environment in coal mines is relatively complex, and there are indeed some high-speed and short-term interference signals. The amplitude of these signals may be very large, but the duration is very short. In fact, they may not produce sparks. When the sampling circuit misjudges this kind of signal, it will immediately cut off the output of the intrinsically safe power supply, thus causing the load device to restart, which is the problem of EMC performance mentioned above. Summary of the Invention
[0004] Existing technical solutions only focus on the spark performance and ignore the hot pluggability and EMC performance, resulting in poor user experience and abnormal operation of equipment under harsh conditions, which may lead to the loss of key data in coal mines. The present invention is proposed to solve this problem. The present invention can take into account the spark performance, hot pluggability and EMC performance at the same time, and can ensure the reliable and stable operation of the load device powered by the intrinsically safe power supply when hot plugging devices and when there are high-speed, short-term and large-amplitude interference signals without generating sparks that can cause explosion.
[0005] The present invention adopts the following technical solutions.
[0006] In the first aspect of the present invention, an intrinsically safe power supply protection system is proposed, including: a current sensor, a comparison circuit, a microcontroller, a negative feedback control unit, a three-way selection circuit and a temperature sensor, characterized in that: The input end of the current sensor is connected to the output end of the intrinsically safe power supply to measure its output current. The output end of the current sensor is connected to the input end of the comparison circuit. The comparison circuit compares the output value of the current sensor with the set value and outputs a current comparison signal. The output end of the comparison circuit is connected to the first input end of the microcontroller; the temperature sensor measures the temperature of the MOS at the output end of the intrinsically safe power supply and transmits the measured temperature to the second input end of the microcontroller; the output end of the microcontroller is connected to the control end of the three-way selection circuit to control one of the three input ends of the three-way selection circuit to receive the signal as the output of the three-way selection circuit. The output end of the current sensor is simultaneously connected to the first input end of the negative feedback control unit. The second input end of the negative feedback control unit receives the set current limit given value. The output end of the negative feedback control unit is connected to the first input end of the three-way selection circuit. The negative feedback control unit outputs to control the gate voltage of the MOS transistor at the output end of the intrinsically safe power supply, so as to limit the output current of the intrinsically safe power supply within the current limit given value. The second input end and the third input end of the three-way selection circuit receive the MOS transistor turn-off signal and the MOS transistor turn-on signal respectively; the output end of the three-way selection circuit is connected to the gate of the MOS at the output end of the intrinsically safe power supply.
[0007] Preferably, the current sensor is a Hall sensor or a current sampling resistor.
[0008] Preferably, the comparison circuit is composed of a comparator, first and second voltage dividing resistors R1 and R2. The output end of the current sensor is connected to the IN+ input end of the comparator. VCC is connected to the IN- input end of the comparator through R1, and GND is connected to the IN- input end of the comparator through R2; the output end of the comparator is connected to the first input end of the microcontroller.
[0009] Preferably, the negative feedback control unit is controlled by PID, and the output gate voltage is the gate voltage that enables the MOS transistor at the output end of the intrinsically safe power supply to operate in the amplification region.
[0010] Preferably, the three-way selection circuit is composed of first and second analog multiplexers U1 and U2. The output end of the negative feedback control unit is connected to the first input end of the second analog multiplexer U2. The second input end of the second analog multiplexer U2 receives the MOS turn-off signal. The control end of the second analog multiplexer U2 is connected to the second output end of the microcontroller. The output end of the second analog multiplexer U2 is connected to the second input end of the first analog multiplexer U1; the second input end of the first analog multiplexer U1 receives the MOS turn-on signal. The control end of the first analog multiplexer U1 is connected to the first output end of the microcontroller. The output end of the first analog multiplexer U1 is connected to the gate of the MOS at the output end of the intrinsically safe power supply.
[0011] Preferably, the microcontroller is an FPGA that supports parallel execution.
[0012] A second aspect of the present invention proposes a control method for the intrinsically safe power supply protection system described in the first aspect of the present invention, including: Collect the temperature of the MOS at the output end of the intrinsically safe power supply, and calculate the current limiting duration and the turn-off duration of the MOS at the output end of the intrinsically safe power supply according to the received temperature; Judge whether overcurrent or short circuit occurs according to the output of the comparison circuit, If so, control the three-way selection circuit to output a definite high level; otherwise, within the current limiting duration, control the first input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; and during this process, judge in real time whether overcurrent or short circuit occurs according to the output of the comparison circuit. If so, control the three-way selection circuit to output a definite high level; If overcurrent or short circuit never occurs, within the turn-off duration after reaching the current limiting duration, control the second input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; after this process lasts for the turn-off duration, return to perform the control within the current limiting duration.
[0013] Preferably, the calculating the current limiting duration and the turn-off duration of the MOS at the output end of the intrinsically safe power supply according to the received temperature is specifically: The higher the temperature, the longer the calculated current limiting duration of the MOS at the output end of the intrinsically safe power supply, and the shorter the turn-off duration.
[0014] Preferably, the higher the temperature, the longer the calculated current limiting duration of the MOS at the output end of the intrinsically safe power supply, and the shorter the turn-off duration is specifically:
[0015]
[0016] Among them, T is the set time reference, W is the temperature, is the current limiting duration of the MOS at the output end of the intrinsically safe power supply, is the turn-off duration of the MOS at the output end of the intrinsically safe power supply, w 1 is the set lower temperature limit, w 2 is the set upper temperature limit, w 2 > w 1, and M is the set exponential coefficient.
[0017] Preferably, the control three-way selection circuit outputs a definite high level, specifically as follows: Control the first input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; Or control the first input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1.
[0018] The beneficial effects of the present invention are as follows. Compared with the prior art, by using the intrinsically safe power supply protection system control method proposed by the present invention, an intrinsically safe power supply with very good spark performance, hot plug performance, and EMC performance can be realized. Since the maximum current is limited within the set current upper limit, the intrinsically safe power supply will not generate sparks that can ignite combustible gases, thus obtaining good spark performance; since during the process of hot plugging resulting in a short circuit of the aviation plug or a capacitor charging impact, the current is limited to a fixed value of the current limiting given value for a period of time and is not directly turned off, it can completely solve the impact caused by the short circuit and capacitor charging process. There is always power during this period, so it will not cause a short-term power outage due to hot plugging, and thus there will be no situation where the device restarts due to this, resulting in the loss of key data; since during the process of a short-duration EMC large voltage pulse, the current is limited to a fixed value of the current limiting given value for a period of time and is not directly turned off, it can avoid device power outage and restart caused by the EMC large voltage pulse. The performance of the intrinsically safe power supply has been improved in all aspects. Description of the Drawings
[0019] 1 Figure 1 is a schematic diagram of the composition of the intrinsically safe power supply protection system; Figure 2 is a schematic diagram of the control method of the intrinsically safe power supply protection system. Detailed Embodiment
[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
[0021] As Figure 1 shown, Embodiment 1 of the present invention proposes an intrinsically safe power supply protection system, including: a current sensor, a comparison circuit, a microcontroller, a negative feedback control unit, a three-way selection circuit, and a temperature sensor, characterized in that: The input end of the current sensor is connected to the output end of the intrinsically safe power supply to measure its output current. The output end of the current sensor is connected to the input end of the comparison circuit. The comparison circuit compares the output value of the current sensor with the set value and outputs a current comparison signal. The output end of the comparison circuit is connected to the first input end of the microcontroller. The temperature sensor measures the temperature of the MOS at the output end of the intrinsically safe power supply and transmits the measured temperature to the second input end of the microcontroller. The output end of the microcontroller is connected to the control end of the three-way selection circuit, controlling one of the three input ends of the three-way selection circuit to receive a signal as the output of the three-way selection circuit. The output end of the current sensor is simultaneously connected to the first input end of the negative feedback control unit. The second input end of the negative feedback control unit receives the set current limit given value. The output end of the negative feedback control unit is connected to the first input end of the three-way selection circuit. The negative feedback control unit outputs to control the gate voltage of the MOS transistor at the output end of the intrinsically safe power supply, so that the output current of the intrinsically safe power supply is limited within the current limit given value. It should be noted that the current limit feedback value is obtained by querying the corresponding value of the intrinsically safe power supply corresponding to the output voltage level in the relevant standard. Under this value, even if a short circuit occurs, there will be no spark that can cause an explosion.
[0022] The second input end and the third input end of the three-way selection circuit receive the MOS transistor turn-off signal and the MOS transistor turn-on signal respectively. The output end of the three-way selection circuit is connected to the gate of the MOS at the output end of the intrinsically safe power supply.
[0023] Preferably, the current sensor is a Hall sensor or a current sampling resistor.
[0024] Preferably, the comparison circuit is composed of a comparator, and first and second voltage dividing resistors R1 and R2. The output end of the current sensor is connected to the IN+ input end of the comparator. VCC is connected to the IN- input end of the comparator through R1, and GND is connected to the IN- input end of the comparator through R2. The output end of the comparator is connected to the first input end of the microcontroller.
[0025] It should be noted that the voltage division values obtained by R1 and R2 should be slightly smaller than the current limit given value, so as to ensure the reliability of the output result of the comparator. Preferably, the negative feedback control unit is controlled by PID, and the output gate voltage is the gate voltage that enables the MOS transistor at the output end of the intrinsically safe power supply to work in the amplification region.
[0026] Preferably, the three-way selection circuit consists of the first and second analog multiplexers U1 and U2. The output terminal of the negative feedback control unit is connected to the first input terminal of the second analog multiplexer U2. The second input terminal of the second analog multiplexer U2 receives the MOS turn-off signal. The control terminal of the second analog multiplexer U2 is connected to the second output terminal of the microcontroller. The output terminal of the second analog multiplexer U2 is connected to the second input terminal of the first analog multiplexer U1. The second input terminal of the first analog multiplexer U1 receives the MOS turn-on signal. The control terminal of the first analog multiplexer U1 is connected to the first output terminal of the microcontroller. The output terminal of the first analog multiplexer U1 is connected to the gate level of the MOS at the output terminal of the intrinsically safe power supply.
[0027] Preferably, the microcontroller is an FPGA that supports parallel execution.
[0028] As Figure 2 shown, Embodiment 2 of the present invention proposes a control method for the intrinsically safe power supply protection system described in Embodiment 1 of the present invention, including: Collect the temperature of the MOS at the output terminal of the intrinsically safe power supply, and calculate the current-limiting duration and turn-off duration of the MOS at the output terminal of the intrinsically safe power supply according to the received temperature; Judge whether overcurrent or short circuit occurs according to the output of the comparison circuit, If so, control the three-way selection circuit to output a definite high level; otherwise, within the current-limiting duration, control the first input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; and during this process, continuously judge whether overcurrent or short circuit occurs according to the output of the comparison circuit. If so, control the three-way selection circuit to output a definite high level; If overcurrent or short circuit never occurs, within the turn-off duration after the current-limiting duration is reached, control the second input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; after this process lasts for the turn-off duration, return to perform the control within the current-limiting duration.
[0029] Preferably, the calculating the current-limiting duration and turn-off duration of the MOS at the output terminal of the intrinsically safe power supply according to the received temperature is specifically: The higher the temperature, the longer the calculated current-limiting duration of the MOS at the output terminal of the intrinsically safe power supply, and the shorter the turn-off duration.
[0030] Preferably, the higher the temperature, the longer the calculated current-limiting duration of the MOS at the output terminal of the intrinsically safe power supply, and the shorter the turn-off duration is specifically:
[0031]
[0032] Among them, T is the set time reference, W is the temperature, is the current limiting duration of the output terminal MOS of the intrinsically safe power supply, is the turn-off duration of the output terminal MOS of the intrinsically safe power supply, w 1 is the set lower temperature limit, w 2 is the set upper temperature limit, w 2 > w 1, and M is the set exponential coefficient.
[0033] Preferably, the control three-way selection circuit outputs a definite high level, specifically: Control the first input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; Or control the first input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1.
[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement that does not deviate from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.
Claims
1. An intrinsically safe power supply protection system, comprising: A current sensor, a comparison circuit, a microcontroller, a negative feedback control unit, a three-way selection circuit and a temperature sensor, characterized in that: The input end of the current sensor is connected to the output end of the intrinsically safe power supply to measure its output current, the output end of the current sensor is connected to the input end of the comparison circuit, the comparison circuit compares the output value of the current sensor with the set value and outputs a current comparison signal, and the output end of the comparison circuit is connected to the first input end of the microcontroller; the temperature sensor measures the temperature of the MOS at the output end of the intrinsically safe power supply, and transmits the measured temperature to the second input end of the microcontroller; the output end of the microcontroller is connected to the control end of the three-way selection circuit, and controls the signal received by one of the three input ends of the three-way selection circuit as the output of the three-way selection circuit; The output end of the current sensor is simultaneously connected to the first input end of the negative feedback control unit, the second input end of the negative feedback control unit receives a set current limiting given value, the output end of the negative feedback control unit is connected to the first input end of the three-way selection circuit, and the negative feedback control unit outputs a gate voltage of the MOS tube at the output end of the intrinsically safe power supply, so that the output current of the intrinsically safe power supply is limited within the current limiting given value; The second input terminal and the third input terminal of the three-way selection circuit receive the MOS tube closing signal and the MOS tube opening signal respectively; the output terminal of the three-way selection circuit is connected to the gate of the output terminal MOS of the intrinsically safe power supply.
2. The intrinsically safe power supply protection system according to claim 1, characterized in that: The current sensor is a Hall sensor or a current sampling resistor.
3. The intrinsically safe power supply protection system according to claim 1, characterized in that: The comparison circuit is composed of a comparator, a first and a second voltage-dividing resistor R1 and R2. The output end of the current sensor is connected to the IN+ input end of the comparator, VCC is connected to the IN- input end of the comparator through R1, and GND is connected to the IN- input end of the comparator through R2; the output end of the comparator is connected to the first input end of the microcontroller.
4. The intrinsically safe power supply protection system according to claim 1, characterized in that: The negative feedback control unit is controlled by PID, and the output gate voltage is the gate voltage that enables the MOS tube at the output end of the intrinsically safe power supply to work in the amplification region.
5. The intrinsically safe power supply protection system according to claim 1, characterized in that: The three-way selection circuit is composed of a first and a second analog multiplexer U1 and U2, the output end of the negative feedback control unit is connected to the first input end of the second analog multiplexer U2, the second input end of the second analog multiplexer U2 receives a MOS shutdown signal, the control end of the second analog multiplexer U2 is connected to the second output end of the microcontroller, and the output end of the second analog multiplexer U2 is connected to the second input end of the first analog multiplexer U1; the second input end of the first analog multiplexer U1 receives a MOS opening signal, the control end of the first analog multiplexer U1 is connected to the first output end of the microcontroller, and the output end of the first analog multiplexer U1 is connected to the gate level of the output end MOS of the intrinsically safe power supply.
6. An intrinsically safe power supply protection system according to claim 1, 3 or 5, characterized in that: The microcontroller is an FPGA supporting parallel execution.
7. A control method using the intrinsically safe power supply protection system according to any one of claims 5 to 6, characterized in that: include: The temperature of the MOS at the output end of the intrinsically safe power supply is collected, and the current limiting duration and the shutdown duration of the MOS at the output end of the intrinsically safe power supply are calculated according to the received temperature; According to the output of the comparison circuit, it is judged whether overcurrent or short circuit occurs. If yes, the three-way selection circuit is controlled to output a certain high level; otherwise, during the current limiting duration, the first input end of the second analog multiplexer U2 is controlled to be connected to the output end of U2, and the second input end of the first analog multiplexer U1 is controlled to be connected to the output end of U1; and in this process, it is determined in real time according to the output of the comparison circuit whether an overcurrent or short circuit occurs, and if yes, the three-way selection circuit is controlled to output a certain high level; If overcurrent or short circuit never occurs, then within the shutdown duration after the current limiting duration is reached, the second input terminal of the second analog multiplexer U2 is controlled to be connected to the output terminal of U2, and the second input terminal of the first analog multiplexer U1 is controlled to be connected to the output terminal of U1; when the process lasts for the shutdown duration, it returns to the control within the current limiting duration.
8. The control method of an intrinsically safe power supply protection system according to claim 7, characterized in that: The current limiting duration and the shutdown duration of the output MOS of the intrinsically safe power supply are calculated according to the received temperature, specifically: The higher the temperature, the longer the calculated current limiting duration of the MOS at the output end of the intrinsically safe power supply, and the shorter the shutdown duration.
9. The intrinsically safe power supply protection system according to claim 8, characterized in that: The higher the temperature, the longer the calculated current limiting duration of the MOS at the output end of the intrinsically safe power supply, and the shorter the shutdown duration, specifically: in, T is the set time base, W is the temperature, is the current limiting duration of the MOS at the output end of the intrinsically safe power supply, is the off-time duration of the output MOS of the intrinsically safe power supply, w 1 is the lower limit of the set temperature, w 2 is the upper temperature limit. w 2> w 1, M is the set exponential coefficient.
10. The control method of an intrinsically safe power supply protection system according to claim 9, characterized in that: The control three-way selection circuit outputs a certain high level, specifically: Controlling the first input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1; Or control the first input terminal of the second analog multiplexer U2 to be connected to the output terminal of U2, and control the second input terminal of the first analog multiplexer U1 to be connected to the output terminal of U1.