Subway ventilation control system

Abstract

The utility model provides a subway ventilation control system, and belongs to the technical field of ventilation control. The subway ventilation control system comprises a frequency conversion control module which comprises a signal enhancement sub-module, a pulse generation sub-module and a ventilation control sub-module; the carbon dioxide concentration detection module is respectively connected with the input end of the signal enhancement sub-module and the input end of the concentration comparison module; the output end of the concentration comparison module is connected with the control end of the switch module; the first end of the switch module is connected with a first power supply, the second end of the switch module is connected with a second power supply, the third end of the switch module is connected with the first end of the ventilation control submodule, and the fourth end of the switch module is connected with the fan; the output end of the signal enhancement sub-module is connected with the input end of the pulse generation sub-module, the output end of the pulse generation sub-module is connected with the control end of the ventilation control sub-module, and the second end of the ventilation control sub-module is connected with the fan. The problem of high energy consumption can be solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of ventilation control, in particular to a subway ventilation control system. BACKGROUND

[0002] With the rapid development of urban rail transit, subway has become an important way for people's daily travel. As a key facility to ensure air quality and passenger comfort in the subway, the importance of the subway ventilation system is self-evident. However, the existing subway ventilation system has the problem of high energy consumption, and has limited adjustment capacity when responding to environmental changes, which cannot achieve precise control and causes energy waste. CONTENT OF THE UTILITY MODEL

[0003] The embodiment of the present disclosure provides a subway ventilation control system to solve the problem of high energy consumption.

[0004] The embodiment of the present disclosure provides a subway ventilation control system, comprising: a carbon dioxide concentration detection module, a concentration comparison module, a variable frequency control module, a switch module and a fan; the variable frequency control module comprises a signal enhancement submodule, a pulse generation submodule and a ventilation control submodule;

[0005] The carbon dioxide concentration detection module is connected with the input end of the signal enhancement submodule and the input end of the concentration comparison module respectively;

[0006] The output end of the concentration comparison module is connected with the control end of the switch module;

[0007] The first end of the switch module is connected with the first power supply, the second end of the switch module is connected with the second power supply, the third end of the switch module is connected with the first end of the ventilation control submodule, and the fourth end of the switch module is connected with the fan;

[0008] The output end of the signal enhancement submodule is connected with the input end of the pulse generation submodule, the output end of the pulse generation submodule is connected with the control end of the ventilation control submodule, and the second end of the ventilation control submodule is connected with the fan.

[0009] In an exemplary embodiment of the present disclosure, the signal enhancement submodule comprises a resistor R1, a resistor R2, a resistor R3, a resistor R8, a capacitor C1 and an operational amplifier U2;

[0010] The first end of the resistor R1 is connected with the carbon dioxide concentration detection module, the second end of the resistor R1 is connected with the first end of the resistor R3, and the second end of the resistor R3 is connected with the non-inverting input end of the operational amplifier U2;

[0011] The inverting input end of the operational amplifier U2 is connected with a reference voltage Vref1, the inverting input end of the operational amplifier U2 is grounded through the resistor R8, and the output end of the operational amplifier U2 is connected with the input end of the pulse generation submodule;

[0012] The first end of the resistor R2 is connected to the inverting input terminal of the operational amplifier U2, and the second end of the resistor R2 is connected to the output terminal of the operational amplifier U2;

[0013] The capacitor C1 is connected in parallel with the resistor R1.

[0014] In an exemplary embodiment of the present disclosure, the pulse generation sub-module comprises a resistor R5, a resistor R6, a resistor R16, a capacitor C3, a capacitor C5, a diode D4, a controller U3 and a voltage comparator U4;

[0015] The first end of the resistor R5 is connected to the output terminal of the signal enhancement sub-module, and the second end of the resistor R5 is connected to the control voltage terminal of the controller U3;

[0016] The trigger terminal and the threshold terminal of the controller U3 are both connected to the ground through the capacitor C3;

[0017] The discharge terminal of the controller U3 is connected to the power supply VCC through the resistor R6;

[0018] The reset terminal and the power terminal of the controller U3 are both connected to the power supply VCC;

[0019] The ground terminal of the controller U3 is grounded;

[0020] The output terminal of the controller U3 is connected to the first end of the resistor R16 and the cathode of the diode D4, respectively;

[0021] The second end of the resistor R16 and the anode of the diode D4 are both connected to the non-inverting input terminal of the voltage comparator U4; the inverting input terminal of the voltage comparator U4 is connected to the output terminal of the signal enhancement sub-module;

[0022] The second end of the resistor R16 and the anode of the diode D4 are both connected to the ground through the capacitor C5.

[0023] In an exemplary embodiment of the present disclosure, the ventilation control sub-module comprises a switch tube Q3 and a switch tube Q4;

[0024] The control terminal of the switch tube Q3 and the control terminal of the switch tube Q4 are both connected to the output terminal of the pulse generation sub-module;

[0025] The first end of the switch tube Q3 is grounded, the second end of the switch tube Q3 is connected to the first end of the switch tube Q4, and the second end of the switch tube Q4 is connected to the third end of the switch module;

[0026] The second end of the switch tube Q3 and the first end of the switch tube Q4 are both connected to the fan.

[0027] In an example embodiment of the present disclosure, the ventilation control submodule further comprises a resistor R7, a resistor R12, a transistor Q1, a transistor Q2, a transistor Q5, a transistor Q6, a diode D1, a diode D2, and a diode D3;

[0028] The emitter of the transistor Q1 and the base of the transistor Q6 are connected to the output end of the pulse generation submodule;

[0029] The base of the transistor Q1 is connected to the power supply, the collector of the transistor Q1 is connected to the power supply through the resistor R7, and the collector of the transistor Q1 is connected to the base of the transistor Q2;

[0030] The emitter of the transistor Q2 is connected to the power supply, the collector of the transistor Q2 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the control end of the switch tube Q3;

[0031] The emitter of the transistor Q6 is grounded, and the collector of the transistor Q6 is connected to the first end of the resistor R12 and the base of the transistor Q5, respectively;

[0032] The second end of the resistor R12 and the emitter of the transistor Q5 are both connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the power supply;

[0033] The collector of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the control end of the switch tube Q4.

[0034] In an example embodiment of the present disclosure, the switch module comprises a transistor Q7 and a relay KM1;

[0035] The base of the transistor Q7 is connected to the output end of the concentration comparison module, the collector of the transistor Q7 is connected to the second power supply, and the emitter of the transistor Q7 is connected to the first power supply end of the relay KM1;

[0036] The second power supply end of the relay KM1 is grounded, the first common end of the relay KM1 is connected to the first power supply, the second common end of the relay KM1 is connected to the second power supply, the first normally open end of the relay KM1 is connected to the first end of the ventilation control submodule, and the second normally closed end of the relay KM1 is connected to the fan.

[0037] In an example embodiment of the present disclosure, the concentration comparison module comprises a comparator U1;

[0038] The non-inverting input end of the comparator U1 is connected to the carbon dioxide concentration detection module, the inverting input end of the comparator U1 receives a reference voltage Vref2, and the output end of the comparator U1 is connected to the control end of the switch module.

[0039] The subway ventilation control system provided by the example embodiment of the present disclosure has the following beneficial effects:

[0040] The present disclosure monitors the carbon dioxide concentration in the subway in real time through the carbon dioxide concentration detection module, ensures the comfort and health of the passenger breathing environment. Combined with the signal enhancer module, the stability and accuracy of signal transmission are improved, providing reliable guarantee for timely response. The concentration comparison module can judge whether the current carbon dioxide concentration is over standard, and once it exceeds the preset range, the switch module is triggered to act, realizing automatic ventilation control and improving work efficiency. The cooperative work of the pulse generation sub-module and the ventilation control sub-module can accurately control the start and stop of the fan, effectively regulate the air circulation in the subway, and is energy-saving and environmentally friendly. Therefore, the present disclosure can solve the problem of high energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0042] Figure 1 is a structural schematic diagram of a subway ventilation control system provided by an embodiment of the present disclosure;

[0043] Figure 2 is a circuit structural schematic diagram of a subway ventilation control system provided by an embodiment of the present disclosure;

[0044] Figure 3 is a circuit structural schematic diagram of another subway ventilation control system provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] In order to make the person skilled in the art better understand the present scheme, the technical solutions in the embodiments of the present scheme will be clearly described below in combination with the drawings in the embodiments of the present scheme. Obviously, the described embodiments are part of the embodiments of the present scheme, not all. Based on the embodiments in the present scheme, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present scheme.

[0046] The terms "include", and other any variants thereof, in the specification and claims of the present scheme and the above-mentioned drawings, refer to "include but not limited to", and are intended to cover non-exclusive inclusion, and are not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0047] The implementation of the present disclosure will be described in detail below in combination with specific drawings:

[0048] Figure 1 A structural schematic diagram of a subway ventilation control system is provided for the embodiments of the present disclosure. Referring to Figure 1 The subway ventilation control system comprises:

[0049] a carbon dioxide concentration detection module 101, a concentration comparison module 103, a variable frequency control module 10, a switch module 106, and a fan 107; the variable frequency control module 10 comprises a signal enhancement sub-module 102, a pulse generation sub-module 104, and a ventilation control sub-module 105;

[0050] The carbon dioxide concentration detection module 101 is connected to the input end of the signal enhancement sub-module 102 and the input end of the concentration comparison module 103, respectively;

[0051] The output end of the concentration comparison module 103 is connected to the control end of the switch module 106;

[0052] The first end of the switch module 106 is connected to a first power supply, the second end of the switch module 106 is connected to a second power supply, the third end of the switch module 106 is connected to the first end of the ventilation control sub-module 105, and the fourth end of the switch module 106 is connected to the fan 107;

[0053] The output end of the signal enhancement sub-module 102 is connected to the input end of the pulse generation sub-module 104, the output end of the pulse generation sub-module 104 is connected to the control end of the ventilation control sub-module 105, and the second end of the ventilation control sub-module 105 is connected to the fan 107.

[0054] In this embodiment, the carbon dioxide concentration detection module 101 is configured to detect the carbon dioxide concentration in the subway environment in real time, and can use a carbon dioxide sensor to convert the detected carbon dioxide concentration into a corresponding voltage signal output. Then, the carbon dioxide concentration detection module 101 sends the voltage signal corresponding to the carbon dioxide concentration to the signal enhancement sub-module 102 and the concentration comparison module 103.

[0055] Considering that the voltage signal output by the carbon dioxide concentration detection module 101 is relatively weak, the signal enhancement sub-module 102 can amplify the voltage signal to improve the strength and quality of the voltage signal, so that it can be better recognized and processed by the pulse generation sub-module 104.

[0056] The concentration comparison module 103 corresponds to a reference voltage that is pre-set, and the reference voltage corresponds to a threshold value of carbon dioxide concentration. The concentration comparison module 103 compares the voltage signal corresponding to the actual carbon dioxide concentration with the reference voltage, and according to the comparison result, outputs a corresponding control signal for controlling the state of the switch module 106.

[0057] The variable frequency control module 10 is configured to control the air exchange amount of the fan 107 according to the actual carbon dioxide concentration change of the carbon dioxide concentration detection module 101.

[0058] The pulse generation submodule 104 generates a corresponding pulse signal according to the enhanced voltage signal input by the signal enhancement submodule 102. The frequency, duty cycle and other parameters of the pulse signal can be adjusted according to the size of the input voltage signal, and the pulse signal will be used to control the ventilation control submodule 105, so as to realize accurate adjustment of the running state of the fan 107.

[0059] The ventilation control submodule 105 adjusts the running parameters such as the rotation speed and air volume of the fan 107 according to the pulse signal input by the pulse generation submodule 104. At the same time, the module also receives the power signal transmitted by the switch module 106 to provide appropriate working power for the fan 107.

[0060] The switch module 106 is configured to switch the power supply and receives the control signal output by the concentration comparison module 103. The first power supply is high voltage, which can be 48V; the second power supply can be low voltage, which can be 12V. When the voltage signal corresponding to the carbon dioxide concentration is less than the preset reference voltage, the switch module 106 is cut off, at this time, the fan 107 is connected to the second power supply, and the air speed of the fan 107 is unchanged; when the voltage signal corresponding to the carbon dioxide concentration is greater than or equal to the preset reference voltage, the switch module 106 is turned on, at this time, the fan 107 is connected to the first power supply, and the first power supply can provide a high voltage for the fan 107, thereby increasing the rotation speed of the fan 107. Moreover, the variable frequency control module 10 can change the duty cycle of the pulse signal output by the variable frequency control module 10 according to the change of the voltage signal corresponding to the carbon dioxide concentration, adjust the rotation speed of the fan 107, change the air exchange amount of the fan 107, and thus improve the air quality in the subway.

[0061] From the above, it can be concluded that the present disclosure can monitor the carbon dioxide concentration in the subway in real time through the carbon dioxide concentration detection module 101, and ensure the comfort and health of the passenger breathing environment. In combination with the signal enhancement submodule 102, the stability and accuracy of signal transmission are improved, and reliable guarantee is provided for timely response. The concentration comparison module 103 can judge whether the current carbon dioxide concentration is over standard, and once it exceeds the preset range, the switch module 106 is immediately triggered to act, realizing automatic ventilation control and improving work efficiency. The cooperative work of the pulse generation submodule 104 and the ventilation control submodule 105 can accurately control the start and stop of the fan 107, effectively adjust the air circulation in the subway, and is energy-saving and environment-friendly. Therefore, the present disclosure can solve the problem of high energy consumption.

[0062] In an embodiment of the present disclosure, reference is made to Figure 2The signal enhancer module 102 comprises resistors R1, R2, R3, R8, a capacitor C1 and an operational amplifier U2.

[0063] The first end of the resistor R1 is connected to the carbon dioxide concentration detection module 101, the second end of the resistor R1 is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the non-inverting input terminal of the operational amplifier U2.

[0064] The inverting input terminal of the operational amplifier U2 is connected to a reference voltage Vref1, and the inverting input terminal of the operational amplifier U2 is grounded through the resistor R8. The output terminal of the operational amplifier U2 is connected to the input terminal of the pulse generation sub-module 104.

[0065] The first end of the resistor R2 is connected to the inverting input terminal of the operational amplifier U2, and the second end of the resistor R2 is connected to the output terminal of the operational amplifier U2.

[0066] The capacitor C1 is connected in parallel with the resistor R1.

[0067] In this embodiment, the carbon dioxide concentration detection module 101 outputs a voltage signal representing the carbon dioxide concentration. The signal first passes through a low-pass filter circuit composed of the resistor R1 and the capacitor C1 to filter out high-frequency noise. The filtered voltage signal enters the non-inverting input terminal of the operational amplifier U2 through the resistor R3.

[0068] The operational amplifier U2 amplifies the difference between the voltage signal at the non-inverting input terminal and the reference voltage Vref1 at the inverting input terminal, and the amplification factor is determined by the resistances of the resistors R2 and R3.

[0069] The amplified voltage signal is output from the output terminal of the operational amplifier U2 and then sent to the pulse generation sub-module 104 to provide an input signal for subsequent pulse signal generation.

[0070] The resistors R2 and R8 form a feedback circuit, and the resistor R8 provides a DC bias path for the inverting input terminal of the operational amplifier U2, ensuring that the operational amplifier U2 can work normally in a static state. The resistor R8 can stabilize the potential at the inverting input terminal of the operational amplifier U2, avoiding abnormal operation of the operational amplifier U2 due to fluctuations in the input signal or other factors.

[0071] From the above, it can be concluded that the embodiment effectively amplifies the voltage signal from the carbon dioxide concentration detection module 101, improving the strength and stability of the voltage signal. At the same time, the feedback circuit composed of the resistors R2 and R8, and the introduction of the reference voltage Vref1, ensure the accuracy of signal amplification. In addition, the capacitor C1 is connected in parallel with the resistor R1, further enhancing the anti-interference ability of the signal and ensuring the reliability of signal transmission.

[0072] In one embodiment of the present disclosure, the referenceFigure 2 The pulse generation sub-module 104 comprises a resistor R5, a resistor R6, a resistor R16, a capacitor C3, a capacitor C5, a diode D4, a controller U3 and a voltage comparator U4.

[0073] The first end of the resistor R5 is connected to the output end of the signal enhancement sub-module 102, and the second end of the resistor R5 is connected to the control voltage end of the controller U3.

[0074] The trigger end and the threshold end of the controller U3 are both grounded through the capacitor C3.

[0075] The discharge end of the controller U3 is connected to the power supply VCC through the resistor R6.

[0076] The reset end and the power supply end of the controller U3 are both connected to the power supply VCC.

[0077] The ground end of the controller U3 is grounded.

[0078] The output end of the controller U3 is connected to the first end of the resistor R16 and the cathode of the diode D4, respectively.

[0079] The second end of the resistor R16 and the anode of the diode D4 are both connected to the non-inverting input end of the voltage comparator U4; the inverting input end of the voltage comparator U4 is connected to the output end of the signal enhancement sub-module 102.

[0080] The second end of the resistor R16 and the anode of the diode D4 are both grounded through the capacitor C5.

[0081] In this embodiment, the enhanced voltage signal output by the signal enhancement sub-module 102 is transmitted to the control voltage end of the controller U3 through the resistor R5, thereby providing a control signal for the controller U3.

[0082] The controller U3 generates a corresponding pulse signal according to the control voltage and the voltage of the trigger end and the threshold end, and outputs the pulse signal from the output end.

[0083] The pulse signal output by the controller U3 is processed by the resistor R16, the diode D4 and the capacitor C5 for current limiting, shaping and filtering, and then transmitted to the non-inverting input end of the voltage comparator U4.

[0084] The controller U3 can be a timer 555 chip. The capacitor C3 is used to filter the trigger signal and the threshold signal, remove high-frequency interference, and make the signal more stable. The resistor R6 provides a pull-up resistor for the discharge end, ensuring that the capacitor C3 is charged or discharged at the right time. The reset end and the power supply end provide working power and reset signals for the controller U3, ensuring its normal start and operation. The ground end provides a reference potential for the controller U3. The output end is used to output a pulse signal.

[0085] The voltage comparator U4 compares the voltage signal at the non-inverting input with the voltage signal at the inverting input (i.e. the output signal of the signal enhancer module 102), and outputs a pulse signal which has been further shaped and adjusted, and which will be used to control the ventilation control module 105, thereby regulating the operation of the fan 107.

[0086] From the above, it can be seen that the embodiment effectively converts the output signal of the signal enhancer module 102 into a control pulse. The capacitor C3 provides a stable trigger and threshold reference for the controller U3, ensuring the accuracy and stability of the pulse generation. The use of the resistor R16 in combination with the diode D4, and the filtering effect of the capacitor C5, further enhances the anti-interference ability of the pulse signal. The introduction of the voltage comparator U4 achieves accurate comparison of the input signal, thereby outputting a stable pulse signal.

[0087] In one embodiment of the present disclosure, with reference to Figure 2 The ventilation control module 105 comprises a switch tube Q3 and a switch tube Q4.

[0088] The control end of the switch tube Q3 and the control end of the switch tube Q4 are both connected to the output end of the pulse generation module 104.

[0089] The first end of the switch tube Q3 is grounded, the second end of the switch tube Q3 is connected to the first end of the switch tube Q4, and the second end of the switch tube Q4 is connected to the third end of the switch module 106.

[0090] The second end of the switch tube Q3 and the first end of the switch tube Q4 are both connected to the fan 107.

[0091] In the embodiment, the switch tube Q3 and the switch tube Q4 act as power switching devices, and control their own conduction and cutoff according to the high and low levels of the pulse signal. Among them, a P-channel enhancement mode field effect transistor can be used as the switch tube Q3, and an N-channel enhancement mode field effect transistor can be used as the switch tube Q4. When the pulse signal is at a high level, the switch tube Q3 is cut off and the switch tube Q4 is turned on; when the pulse signal is at a low level, the switch tube Q3 is turned on and the switch tube Q4 is cut off. By changing the duty cycle (ratio of high level time to period) of the pulse signal, the average power of the fan 107 can be adjusted, thereby controlling the speed and air volume of the fan 107.

[0092] The switch tube Q3 and the switch tube Q4 can switch between conduction and cutoff according to the duty cycle of the pulse signal output by the pulse generation module 104, so that the speed of the fan 107 changes.

[0093] From the above, it can be seen that the embodiment ensures fast response and accurate execution of the control signal by directly connecting the pulse generation module 104 with the switch tubes Q3 and Q4, thereby enhancing the ventilation efficiency of the embodiment.

[0094] In one embodiment of the present disclosure, referring to Figure 3 The ventilation control sub-module 105 further comprises a resistor R7, a resistor R12, a transistor Q1, a transistor Q2, a transistor Q5, a transistor Q6, a diode D1, a diode D2 and a diode D3.

[0095] The emitter of the transistor Q1 and the base of the transistor Q6 are connected to the output of the pulse generation sub-module 104.

[0096] The base of the transistor Q1 is connected to the power supply, the collector of the transistor Q1 is connected to the power supply through the resistor R7, and the collector of the transistor Q1 is connected to the base of the transistor Q2.

[0097] The emitter of the transistor Q2 is connected to the power supply, the collector of the transistor Q2 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the control end of the switch tube Q3.

[0098] The emitter of the transistor Q6 is grounded, and the collector of the transistor Q6 is connected to the first end of the resistor R12 and the base of the transistor Q5, respectively.

[0099] The second end of the resistor R12 and the emitter of the transistor Q5 are both connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the power supply.

[0100] The collector of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the control end of the switch tube Q4.

[0101] In this embodiment, in order to improve the driving ability of the fan 107, the above-mentioned components are added as a driving unit. In this embodiment, N-channel enhancement mode field effect transistors can be used as the switch tube Q3 and the switch tube Q4.

[0102] When the pulse generation sub-module 104 outputs a low-level pulse signal, the emitter potential of the transistor Q1 rises. Since the base is connected to the power supply 3.3V, when the voltage difference is greater than or equal to 0.7V, the transistor Q1 is turned on, and the current of its collector increases, so that the base of the transistor Q2 has current flowing in, and the transistor Q2 is also turned on. At this time, the power supply provides a high-level signal to the control end of the switch tube Q3 through the transistor Q2 and the diode D1, so that the switch tube Q3 is turned on. The diode D1 plays a role of isolation and protection, preventing the reverse voltage from affecting the transistor Q2. R7 is used for current limiting and voltage dividing, to ensure that the transistor Q1, the transistor Q2 and the switch tube Q3 work in a safe current and voltage range.

[0103] When the pulse generation sub-module 104 outputs a high-level pulse signal, the base of the triode Q6 obtains a high level, the triode Q6 is turned on, and the collector potential is lowered. The base current of the triode Q5 increases, and the triode Q5 is turned on. At this time, the power supply provides a high-level signal to the control end of the switch tube Q4 through the diode D3, the triode Q5 and the diode D2, so that the switch tube Q4 is turned on. The diodes D2 and D3 also play the role of isolation and protection, and the resistor R12 is used for current limiting and voltage division, to ensure the stability and reliability of the circuit.

[0104] From the above, it can be seen that the embodiment not only improves the driving ability of the fan 107, but also intelligently adjusts the working state of the fan 107 according to environmental requirements, to realize efficient and energy-saving ventilation control.

[0105] In an embodiment of the present disclosure, with reference to Figure 2 , the switch module 106 includes a triode Q7 and a relay KM1;

[0106] The base of the triode Q7 is connected to the output end of the concentration comparison module 103, the collector of the triode Q7 is connected to the first power supply, and the emitter of the triode Q7 is connected to the first power supply end of the relay KM1;

[0107] The second power supply end of the relay KM1 is grounded, the first common end of the relay KM1 is connected to the first power supply, the second common end of the relay KM1 is connected to the second power supply, the first normally open end of the relay KM1 is connected to the first end of the ventilation control sub-module 105, and the second normally closed end of the relay KM1 is connected to the fan 107.

[0108] In the embodiment, the triode Q7 is configured to control the working of the relay KM1 according to the signal output by the concentration comparator, so as to realize the switching of the power supply of the fan 107. When the concentration comparator outputs a high-level signal, the triode Q7 is turned on, at this time, the current can flow from the collector of the triode Q7 to the emitter of the triode Q7, and then provide current for the coil of the relay KM1, that is, the coil is powered on, the coil generates a magnetic field, so that the contacts of the relay KM1 act to switch. When the concentration comparison module 103 outputs a low-level signal, the triode Q7 is cut off, and there is no current passing through the coil of the relay KM1, that is, the coil is powered off, the magnetic field disappears, and the contacts return to the initial state.

[0109] The first power supply can be 48V, and the second power supply can be 12V. At this time, using two power supplies can meet the different power supply requirements of the fan 107. When the relay KM1 is not actuated, the first normally open end of the relay KM1 is disconnected from the first common end of the relay KM1; when the relay KM1 is actuated (the coil is powered), the first normally open end of the relay KM1 is closed, connecting the first power supply to the ventilation control submodule 105 to power the ventilation control submodule 105 and make it start working. When the relay KM1 is not actuated, the second normally closed end of the relay KM1 is closed to the second common end of the relay KM1, and the fan 107 can obtain power supply from the second power supply; when the relay is actuated, the second normally closed end is disconnected, cutting off the connection between the fan 107 and the second power supply.

[0110] For example, when the carbon dioxide concentration exceeds the standard, the concentration comparison module 103 detects that the carbon dioxide concentration in the subway exceeds the preset threshold, and outputs a high-level signal to the base of the transistor Q7. The transistor Q7 is turned on, and the current passes through the coil of the relay KM1, and the coil generates a magnetic field to actuate the contacts of the relay KM1. The first normally open end of the relay KM1 is closed, and the first power supply powers the ventilation control submodule 105, and the ventilation control submodule 105 starts to control the operating state of the fan 107 according to the signal of the pulse generation submodule 104. At the same time, the second normally closed end of the relay KM1 is disconnected, and the fan 107 no longer directly obtains power from the second power supply, but is precisely controlled by the ventilation control submodule 105.

[0111] From the above, it can be seen that the transistor Q7 acts as a switching element, and its base receives the signal of the concentration comparison module 103, accurately responds to environmental changes, and effectively improves the sensitivity of the system. The introduction of the relay KM1 not only enhances the stability and safety of the circuit, but also realizes flexible switching of the first power supply and the second power supply through its double common end design. In addition, the switching module 106 can automatically adjust the ventilation state according to the environmental concentration, which not only guarantees the air quality, but also optimizes the energy utilization.

[0112] In an embodiment of the present disclosure, referring to Figure 2 The concentration comparison module 103 includes a comparator U1;

[0113] The non-inverting input terminal of the comparator U1 is connected to the carbon dioxide concentration detection module 101, the inverting input terminal of the comparator U1 receives a reference voltage Vref2, and the output terminal of the comparator U1 is connected to the control end of the switching module 106.

[0114] In the embodiment, the concentration comparison module 103 is configured to determine whether the actual concentration of carbon dioxide in the subway environment exceeds the preset safety threshold, and to compare the voltage signal output by the carbon dioxide concentration detection module 101 with the reference voltage Vref2 through the comparator U1 to generate a high-level or low-level signal, and further control the switch module 106.

[0115] For example, when the actual carbon dioxide concentration is lower than the threshold, the voltage signal output by the carbon dioxide concentration detection module 101 is lower than the reference voltage Vref2, that is, the voltage at the same-phase input end of the comparator U1 is lower than the voltage at the opposite-phase input end, and the output end of the comparator U1 outputs a low-level signal. The low-level signal is transmitted to the control end of the switch module 106, so that the triode Q7 in the switch module 106 is cut off, and the relay KM1 is not actuated.

[0116] When the actual carbon dioxide concentration reaches or exceeds the threshold, the voltage signal output by the carbon dioxide concentration detection module 101 is greater than or equal to the reference voltage Vref2, and the output end of the comparator U1 outputs a high-level signal. The high-level signal is transmitted to the control end of the switch module 106, so that the triode Q7 in the switch module 106 is turned on, the relay KM1 coil is energized, and the contact of the relay KM1 is actuated.

[0117] As can be seen from the above, the concentration comparison module 103 compares the voltage signal of the carbon dioxide concentration detection module 101 with the preset reference voltage Vref2, ensuring the accuracy and reliability of the control switch module 106, and realizing the instant response to the ventilation control submodule 105.

[0118] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than limit them; although the foregoing embodiments of the present disclosure have been described in detail, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features thereof; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A subway ventilation control system, characterized by, The carbon dioxide concentration detection module, the concentration comparison module, the frequency conversion control module, the switch module and the fan; the frequency conversion control module includes a signal enhancer sub-module, a pulse generation sub-module and a ventilation control sub-module; The carbon dioxide concentration detection module is connected with the input end of the signal enhancer sub-module and the input end of the concentration comparison module respectively; The output end of the concentration comparison module is connected with the control end of the switch module; The first end of the switch module is connected with the first power supply, the second end of the switch module is connected with the second power supply, the third end of the switch module is connected with the first end of the ventilation control sub-module, and the fourth end of the switch module is connected with the fan; The output end of the signal enhancer sub-module is connected with the input end of the pulse generation sub-module, the output end of the pulse generation sub-module is connected with the control end of the ventilation control sub-module, and the second end of the ventilation control sub-module is connected with the fan.

2. A subway ventilation control system as claimed in claim 1, wherein, The signal enhancer sub-module includes a resistor R1, a resistor R2, a resistor R3, a resistor R8, a capacitor C1 and an operational amplifier U2; The first end of the resistor R1 is connected with the carbon dioxide concentration detection module, the second end of the resistor R1 is connected with the first end of the resistor R3, and the second end of the resistor R3 is connected with the non-inverting input end of the operational amplifier U2; The inverting input end of the operational amplifier U2 is connected with a reference voltage Vref1, the inverting input end of the operational amplifier U2 is grounded through the resistor R8, and the output end of the operational amplifier U2 is connected with the input end of the pulse generation sub-module; The first end of the resistor R2 is connected with the inverting input end of the operational amplifier U2, and the second end of the resistor R2 is connected with the output end of the operational amplifier U2; The capacitor C1 is connected with the resistor R1 in parallel.

3. The subway ventilation control system of claim 1, wherein The pulse generation sub-module includes a resistor R5, a resistor R6, a resistor R16, a capacitor C3, a capacitor C5, a diode D4, a controller U3 and a voltage comparator U4; The first end of the resistor R5 is connected with the output end of the signal enhancer sub-module, and the second end of the resistor R5 is connected with the control voltage end of the controller U3; The trigger end and the threshold end of the controller U3 are both grounded through the capacitor C3; The discharge end of the controller U3 is connected with the power supply VCC through the resistor R6; The reset end and the power supply end of the controller U3 are both connected with the power supply VCC; The grounding end of the controller U3 is grounded; The output end of the controller U3 is connected with the first end of the resistor R16 and the cathode of the diode D4 respectively; The second end of the resistor R16 and the anode of the diode D4 are both connected with the non-inverting input end of the voltage comparator U4, and the inverting input end of the voltage comparator U4 is connected with the output end of the signal enhancer sub-module; The second end of the resistor R16 and the anode of the diode D4 are both grounded through the capacitor C5.

4. The subway ventilation control system of claim 1, wherein The ventilation control sub-module includes a switch tube Q3 and a switch tube Q4; The control end of the switch tube Q3 and the control end of the switch tube Q4 are both connected with the output end of the pulse generation sub-module; The first end of the switch tube Q3 is grounded, the second end of the switch tube Q3 is connected to the first end of the switch tube Q4, and the second end of the switch tube Q4 is connected to the third end of the switch module. The second end of the switch tube Q3 and the first end of the switch tube Q4 are both connected to the fan.

5. A subway ventilation control system as claimed in claim 4, wherein, The ventilation control submodule further comprises resistors R7, R12, transistors Q1, Q2, Q5, Q6, diodes D1, D2 and D3. The emitter of the transistor Q1 and the base of the transistor Q6 are both connected to the output of the pulse generation submodule. The base of the transistor Q1 is connected to the power supply, the collector of the transistor Q1 is connected to the power supply through the resistor R7, and the collector of the transistor Q1 is connected to the base of the transistor Q2. The emitter of the transistor Q2 is connected to the power supply, the collector of the transistor Q2 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the control end of the switch tube Q3. The emitter of the transistor Q6 is grounded, and the collector of the transistor Q6 is connected to the first end of the resistor R12 and the base of the transistor Q5, respectively. The second end of the resistor R12 and the emitter of the transistor Q5 are both connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the power supply. The collector of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the control end of the switch tube Q4.

6. A subway ventilation control system as claimed in claim 1, wherein, The switch module comprises a transistor Q7 and a relay KM1. The base of the transistor Q7 is connected to the output of the concentration comparison module, the collector of the transistor Q7 is connected to the second power supply, and the emitter of the transistor Q7 is connected to the first power supply end of the relay KM1. The second power supply end of the relay KM1 is grounded, the first common end of the relay KM1 is connected to the first power supply, the second common end of the relay KM1 is connected to the second power supply, the first normally open end of the relay KM1 is connected to the first end of the ventilation control submodule, and the second normally closed end of the relay KM1 is connected to the fan.

7. A subway ventilation control system as claimed in claim 1, wherein, The concentration comparison module comprises a comparator U1. The non-inverting input of the comparator U1 is connected to the carbon dioxide concentration detection module, the inverting input of the comparator U1 receives a reference voltage Vref2, and the output of the comparator U1 is connected to the control end of the switch module.

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