Subway heat exhaust fan control method based on closed-loop control algorithm

Abstract

The invention discloses a subway heat removal fan control system based on a closed-loop control algorithm. The subway heat removal fan control system comprises a temperature sensor, a heat removal fan, a frequency converter, a COM communication module, an I / O module, a programmable logic controller and a comprehensive monitoring system. The comprehensive monitoring system provides a human-computer interface for monitoring the programmable logic controller, and can set a target value of a controlled object and monitor a control effect; the temperature sensor is connected with the programmable logic controller through an I / O module, and the programmable logic controller is connected to a frequency converter of the heat removal fan through a COM communication module. A control algorithm in the programmable logic controller forms a control instruction of the frequency converter of the heat extraction fan after the operation of the closed-loop controller according to a station tunnel temperature set value input by a human-computer interface of the comprehensive monitoring system and a temperature deviation of a station tunnel outbound end collected by the temperature sensor; the rotating speed of the heat removal fan is adjusted according to the station tunnel temperature, and the purposes of ventilation, heat removal and cooling are achieved.

Description

Technical Field

[0001] The present invention relates to an urban rail transit environment and equipment monitoring system (BAS), and in particular to a control method for a heat exhaust fan of an urban subway environment and equipment monitoring system (BAS). Background Art

[0002] The subway's high efficiency, speed, and safety have made it one of the main means of transportation in major cities in China. However, most subway stations are built underground, and the air environment in the tunnel is closed. The heat generated by the train causes the air environment in the station tunnel to deteriorate. The heat generated by the train mainly comes from the heat dissipated by the train's brakes, the heat from the train's resistance, the heat from the acceleration loss, and the heat generated by the train's air conditioning condenser. In order to maintain the environmental requirements in the subway tunnel, the excess heat in the tunnel needs to be discharged in a timely manner. At present, tunnel heat is mainly discharged in the following ways: The first is to use the "piston wind" generated by the train when it is running at high speed to dissipate heat. The air volume of the piston wind is very large and it is the main power for ventilation and heat dissipation in the tunnel; the second is to use the track heat dissipation fan installed under the platform or on the top of the track; the third is to use the station ventilation and air conditioning system to dissipate the heat that is transferred to the station through conduction of the shield door and convection when the shield door is opened. For the third method, due to the function of the shield door, the heat discharged is limited. Most of the heat is discharged through the first method, and the first method does not require additional energy consumption and should be fully utilized. If there is still heat that cannot be discharged in time, it needs to be realized through the second method. For the second heat dissipation method, how to more effectively control the tunnel temperature and reduce the energy consumption of the heat dissipation fan has been studied. At present, there are roughly the following control methods: First, control the operating frequency of the heat dissipation fan according to the logarithm of the train operation. Second, directly control the frequency of the heat dissipation fan through the train timetable. Third, use photoelectric sensors to detect the train entry and exit events, and control the frequency of the heat dissipation fan inverter based on this. For example, "CN202073836U Energy-saving control system for heat exhaust fan of subway track". Fourth, after measuring the temperature of the tunnel, the heat exhaust fan is controlled in segmented frequency according to the set temperature. For example, "CN108999627B Energy-saving control method and system for heat exhaust fan of subway track".

[0003] The current control mode basically takes into account the heat generated by the train and adopts an open-loop control mode. Directly setting the frequency of the heat exhaust fan inverter has low control accuracy and a large margin, which is easy to cause energy waste. Article 13.2.5 of the "GB50157-2013 Metro Design Code" has clear regulations on tunnel temperature, that is, when the train compartment is equipped with air conditioning and the station is not equipped with a fully enclosed platform door, it shall not be higher than 35°C; when the train compartment is equipped with air conditioning and the station is equipped with a fully enclosed platform door, it shall not be higher than 40°C. The choice of tunnel temperature control target directly affects the comfort and economy of personnel. The general principle is that under the premise of meeting relevant standards and personnel comfort requirements, the set value of the tunnel temperature should be as high as possible to create conditions for energy-saving control of the heat exhaust fan.

[0004] According to the existing research results on the temperature distribution in station tunnels, the air temperature in station tunnels is high in the middle and low at both ends, where the temperature at the station starting point (vehicle entry point) is lower than the temperature at the end point (vehicle exit point), that is, the temperature in the middle of the station > the temperature at the exit point > the temperature at the entry point. Further research shows that the relationship between the temperature change rates of the three measuring points is: the temperature change rate in the middle of the station > the temperature change rate at the entry point > the temperature change rate at the exit point. Summary of the invention

[0005] The purpose of the present invention is to propose a heat exhaust fan control system based on a closed-loop control algorithm based on the provisions of the subway design specification for tunnel temperature and on the basis of existing temperature distribution research. In the control process, the tunnel temperature at the exit is taken as the control object, and the control instructions of the heat exhaust fan inverter are formed through the closed-loop control algorithm. Thus, the purpose of reducing the energy consumption of the heat exhaust fan is achieved while realizing the control of the tunnel temperature at the exit.

[0006] In order to more accurately control the heat exhaust fan of the BAS system and achieve energy saving while removing excess heat, the specific technical solution adopted by the present invention is: A control system for a subway heat exhaust fan based on a closed-loop control algorithm includes: a temperature sensor, a heat exhaust fan, a frequency converter, a COM communication module, an I / O module, a programmable logic controller, and an integrated monitoring system. The integrated monitoring system provides a human-machine interface for monitoring the programmable logic controller, which can set the target value of the controlled object and monitor the control effect. The temperature sensor is connected to the programmable logic controller through the I / O module, and the programmable logic controller is connected to the frequency converter of the heat exhaust fan through the COM communication module. The control algorithm in the programmable logic controller forms a control instruction for the heat exhaust fan frequency converter based on the station tunnel temperature set value input by the human-machine interface of the integrated monitoring system and the temperature deviation at the exit end of the station tunnel collected by the temperature sensor after calculation by the closed-loop controller. The speed of the heat exhaust fan is adjusted according to the station tunnel temperature to achieve the purpose of ventilation, heat exhaust and cooling.

[0007] The closed-loop controller is composed of a proportional controller P, an integral controller I, a differential controller D and a limiting module, wherein the integral controller I has an anti-integral saturation function, and the anti-integral saturation function module is implemented based on a limit-weakening integral algorithm. The tunnel temperature set value SP(t) set by the human-machine interface of the integrated monitoring system (7) is compared with the station tunnel temperature measurement value PV(t) collected by the programmable logic controller (6) to form a difference e(t), as shown in Formula 1. The difference e(t) is used as the input of the closed-loop control algorithm, and the control output f(t) is obtained after passing through the PID operation controller, as shown in Formula 2. After passing through the limiting module, the output F(t) is used as a control instruction to adjust the controlled object. Through the adjustment, the measured value PV(t) tends to the set value, so that the difference e(t) is reduced, thereby adjusting the adjustment force of the controlled object in the next control cycle. Due to the inertia of the controlled object, the final trend is that the measured value PV(t) fluctuates around the set value SP(t) within a certain range.

[0008] , , In the above formula, K P is the proportional magnification factor, T I is the integration time, T D is the differential time. These three parameters are the main adjustment parameters of the closed-loop control algorithm and need to be appropriately selected according to the characteristics of the controlled object.

[0009] The tunnel temperature constant SP(t) is set through the human-machine interface of the integrated monitoring system, for example, it is set to 30°C. This set value is used as the input value, and is compared with the station tunnel temperature (exit temperature) PV(t) value collected by the programmable logic controller. The difference e(t) formed is used as the input of the closed-loop control algorithm, and the control output f(t) is obtained after passing through the PID controller.

[0010] In the early stage of subway operation, winter and transition seasons, the set temperature may be higher than the station tunnel temperature for a long time. At this time, the integral link in the control algorithm may accumulate to a large value. When the tunnel temperature rises, the control algorithm is not easy to withdraw from the influence of the integral link, affecting the regulation performance of the system. In order to avoid the influence of integral saturation on the control performance of the system, an algorithm of weakening the integral when encountering a limit is adopted to realize the anti-integral saturation function.

[0011] When the output of the PID controller exceeds the upper limit Fmax of the inverter operating frequency, the amount of deviation greater than 0 is no longer integrated, and only the amount of deviation less than 0 is integrated. Similarly, when the output of the PID controller exceeds the lower limit Fmin of the inverter operating frequency, the amount of deviation less than 0 is no longer integrated, and only the amount of deviation greater than 0 is integrated. This solution can ensure that the calculated value of the control quantity f(t) does not deviate too far from the actual controllable amount, so that when reverse adjustment is required, it can respond quickly, avoid the output staying in the saturation zone for a long time, and will not produce excessive overshoot.

[0012] The result f(t) after PID operation enters the limiter module, which sets the lower limit Fmin of the inverter's operating frequency to prevent the exhaust fan from running at a low speed for a long time, for example, Fmin=5hz. When the tunnel temperature is lower than the set value for a long time, the exhaust fan is always in a stopped state. The upper limit of the exhaust fan's operating frequency is the power frequency, that is, Fmax=50HZ. The effective output of the limiter control module will be used as the control instruction of the exhaust fan's inverter to control the exhaust fan's speed and achieve the purpose of controlling the tunnel temperature.

[0013] Through the anti-integral saturation and limiting modules, when the station tunnel temperature is lower than the set temperature for a long time, the heat exhaust fan will stop running. When the temperature rises above the set temperature, the closed-loop controller will be effectively put into use, thereby achieving the requirement of turning on the heat exhaust fan on demand and achieving the purpose of controlling the station tunnel temperature and saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the control system structure of a subway heat exhaust fan based on a closed-loop control algorithm in this embodiment.

[0015] Among them, there are temperature sensor 1, heat exhaust fan 2, frequency converter 3, COM module 4, I / O module 5, programmable logic controller 6 and integrated monitoring system 7.

[0016] Figure 2 Schematic diagram of closed-loop control principle in this embodiment.

[0017] Figure 3 Schematic diagram of the anti-integral saturation algorithm in this embodiment. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, a control system of a subway heat exhaust fan based on a closed-loop control algorithm includes: a temperature sensor 1, a heat exhaust fan 2, a frequency converter 3, a COM communication module 4, an I / O module 5, a programmable logic controller 6 and an integrated monitoring system 7. The integrated monitoring system 7 provides a human-machine interface for monitoring the programmable logic controller 6, which can set the target value of the controlled object and monitor the control effect. The temperature sensor 1 is connected to the programmable logic controller 6 through the I / O module 4, and the programmable logic controller 6 is connected to the frequency converter 3 of the heat exhaust fan 2 through the COM communication module 4. The control algorithm in the programmable logic controller 6 inputs the set value of the station tunnel temperature according to the human-machine interface of the integrated monitoring system 7, and the deviation of the temperature at the exit end of the station tunnel collected by the temperature sensor 1, and after the closed-loop controller operation, a control instruction of the heat exhaust fan frequency converter is formed. The speed of the heat exhaust fan is adjusted according to the temperature of the station tunnel to achieve the purpose of ventilation, heat exhaust and cooling.

[0020] According to the settings of conventional subway stations, heat exhaust systems are set up for the up and down lines respectively. This control system performs closed-loop control on the heat exhaust fans of the up and down lines respectively according to the controlled objects; the single-side heat exhaust fan is used for explanation, as follows: like Figure 2As shown, the closed-loop control algorithm as the control core runs in the programmable logic controller 6. The closed-loop control algorithm is composed of a proportional controller P, an integral controller I, a differential controller D and a limiter module, wherein the integral controller has an anti-integral saturation function, which is implemented based on the limit-weakening integral algorithm. The tunnel temperature value SP(t) set in the integrated monitoring system 7 is compared with the station tunnel exit temperature sampled by the I / O module to form a deviation value e(t). The deviation value e(t) is used as the input of the proportional controller P, the integral controller I and the differential controller D. The output f(t) of the PID controller is the algebraic sum of the calculation results of the three controllers. In order to match the control instructions of the frequency converter and obtain better control effects, the output f(t) of the PID controller enters the limiter module, and after passing through the limiter module, the output F(t) is used as the control instruction to adjust the controlled object. The limiter module has a change rate limiting function, which makes the adjustment instruction relatively smooth. Through regulation, the measured value PV(t) tends to the set value, which reduces the difference e(t), thereby adjusting the regulation force of the controlled object in the next control cycle. The final trend is that the measured value PV(t) fluctuates around the set value SP(t) within a certain range. The anti-integral saturation function is integrated in the integral controller. The specific logic is as follows Figure 3 shown.

[0021] exist Figure 3 In. The integral controller first determines whether the PID controller output is in an over-limit state based on the state output of the limit module. When the output of the PID controller exceeds the upper limit Fmax of the inverter operating frequency, the amount of deviation greater than 0 is no longer integrated, and only the amount of deviation less than 0 is integrated. Similarly, when the output of the PID controller exceeds the lower limit Fmin of the inverter operating frequency, the amount of deviation less than 0 is no longer integrated, and only the amount of deviation greater than 0 is integrated. This solution can ensure that the calculated value of the control quantity f(t) does not deviate too far from the actual controllable amount, so that when reverse adjustment is required, it can respond faster, avoid the output staying in the saturation zone for a long time, and will not produce excessive overshoot, thereby improving the control quality.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any equivalent structural changes made using the contents of the description and drawings of the present invention should be included in the patent protection scope of the invention.

Claims

1. A control system for a subway heat exhaust fan based on a closed-loop control algorithm, characterized in that: The invention comprises a temperature sensor (1), a heat exhaust fan (2), a frequency converter (3), a COM communication module (4), an I / O module (5), a programmable logic controller (6) and an integrated monitoring system (7); the integrated monitoring system (7) provides a human-machine interface for monitoring the programmable logic controller (6), and is capable of setting a target value of a controlled object and monitoring a control effect; the temperature sensor (1) is connected to the programmable logic controller (6) via the I / O module (4), and the programmable logic controller (6) is connected to the frequency converter (3) of the heat exhaust fan (2) via the COM communication module (4); the control algorithm in the programmable logic controller (6) generates a control instruction for the heat exhaust fan frequency converter after a closed-loop controller operation based on the station tunnel temperature set value inputted from the human-machine interface of the integrated monitoring system (7) and the temperature deviation at the station tunnel exit end collected by the temperature sensor (1); the speed of the heat exhaust fan is adjusted according to the station tunnel temperature, so as to achieve the purpose of ventilation, heat exhaust and cooling.

2. According to the control system of a subway heat exhaust fan based on a closed-loop control algorithm as claimed in claim 1, it is characterized in that: The closed-loop controller is composed of a proportional controller (P), an integral controller (I), a differential controller (D) and a limiting module, wherein the integral controller (I) has an anti-integral saturation function, and the anti-integral saturation function module is implemented based on a limit-weakened integral algorithm.

3. The control system of a subway heat exhaust fan based on a closed-loop control algorithm according to claim 2 is characterized in that: The tunnel temperature constant SP(t) set by the human-machine interface of the integrated monitoring system (7) is compared with the station tunnel temperature measurement value PV(t) collected by the programmable logic controller (6) to form a difference e(t), see formula (1); the difference e(t) is used as the input of the closed-loop control algorithm, and the control output f(t) is obtained after passing through the PID operation controller, see formula 2; and then the output F(t) is used as the control instruction after passing through the limit module to adjust the controlled object. Through the adjustment, the measured value PV(t) tends to the set value, so that the difference e(t) is reduced, thereby adjusting the adjustment force of the controlled object in the next control cycle; due to the inertia of the controlled object, the final trend is that the measured value PV(t) fluctuates around the set value SP(t) within a certain range; ， ， Among them, KP is the proportional gain factor, TI is the integral time, and TD is the differential time; these three parameters are the main adjustment parameters of the closed-loop control algorithm and need to be appropriately selected according to the characteristics of the controlled object.

4. The control system of a subway heat exhaust fan based on a closed-loop control algorithm according to claim 3 is characterized in that: When the output of the PID controller exceeds the upper limit Fmax of the inverter operating frequency, the amount of deviation greater than 0 is no longer integrated, and only the amount of deviation less than 0 is integrated; similarly, when the output of the PID controller exceeds the lower limit Fmin of the inverter operating frequency, the amount of deviation less than 0 is no longer integrated, and only the amount of deviation greater than 0 is integrated.

5. The control system of a subway heat exhaust fan based on a closed-loop control algorithm according to claim 4 is characterized in that: The result f(t) after PID calculation enters the limiting module. The limiting module sets the lower limit Fmin of the inverter's operating frequency to prevent the heat exhaust fan from running at a low speed for a long time. When the tunnel temperature is lower than the set value for a long time, the heat exhaust fan is always in a stopped state; the upper limit of the heat exhaust fan's operating frequency is the industrial frequency, that is, Fmax=50HZ; the effective output of the limiting module will be used as the control instruction of the inverter of the heat exhaust fan to control the speed of the heat exhaust fan and achieve the purpose of controlling the tunnel temperature.

6. A control system for a subway heat exhaust fan based on a closed-loop control algorithm according to any one of claims 1 to 5, characterized in that: The temperature sensor (1) is installed in a tunnel at the vehicle exit end, with the tunnel temperature at the vehicle exit end being used as a control target.

7. A control system for a subway heat exhaust fan based on a closed-loop control algorithm according to any one of claims 1 to 5, characterized in that: The heat exhaust fan (2) is rotated at a speed controlled by a frequency converter (3), thereby controlling the heat exhaust air volume.

8. A control system for a subway heat exhaust fan based on a closed-loop control algorithm according to any one of claims 2 to 5, characterized in that: The limiting module realizes the functions of limiting the upper and lower limits of the output and the rate of change of the input instruction, so that the input instruction changes within the normal range tend to be smooth.

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