阅读说明：本技术 一种实现岩土原位热响应测试中恒定功率加热的方法 (Method for realizing constant power heating in rock-soil in-situ thermal response test ) 是由 廖全 张�杰 于 2021-06-22 设计创作，主要内容包括：本申请涉及浅层地温能开发与应用技术领域,公开了一种实现岩土原位热响应测试中恒定功率加热的方法,将获取的岩土原位热响应多种原始数据划分为市电电网提供的基础功率和PID控制调节功率；基于双重反馈调节法,根据能量守恒定律对所述PID控制调节功率进行计算,得到PID控制补偿功率的大小；将所述PID控制补偿功率的大小作为脉冲宽度调制技术的控制输入信号,通过对PWM输出占空比的动态调节,实现对PID补偿功率部分的实时控制,利用PID控制具有精度高、自适应能力强、响应速度快等优点来有效克服在岩土原位热响应测试中因市电电压波动带来的功率不恒定问题。(The application relates to the technical field of shallow geothermal energy development and application, and discloses a method for realizing constant power heating in rock-soil in-situ thermal response test, which divides multiple acquired rock-soil in-situ thermal response original data into basic power provided by a mains power grid and PID control regulation power; based on a double feedback regulation method, calculating the PID control regulation power according to an energy conservation law to obtain the PID control compensation power; the PID control compensation power is used as a control input signal of a pulse width modulation technology, real-time control over the PID compensation power part is achieved through dynamic adjustment of PWM output duty ratio, and the problem of inconstant power caused by mains supply voltage fluctuation in rock-soil in-situ thermal response test is effectively solved by utilizing the advantages of high precision, strong self-adaptive capacity, high response speed and the like of PID control.)

1. A method for realizing constant power heating in rock-soil in-situ thermal response test is characterized by comprising the following steps:

dividing the obtained rock-soil in-situ thermal response multiple original data into basic power and PID control regulation power provided by a mains supply power grid;

based on a double feedback regulation method, calculating the PID control regulation power according to an energy conservation law to obtain the PID control compensation power;

and the PID control compensation power is used as a control input signal of a pulse width modulation technology, and real-time control of the PID compensation power part is realized by dynamically adjusting the PWM output duty ratio.

2. The method for realizing constant power heating in rock-soil in-situ thermal response test according to claim 1, wherein the calculating of the PID control regulation power according to the energy conservation law based on a dual feedback regulation method to obtain the PID control compensation power comprises:

according to the measurement of the inlet temperature of the circulating carrier fluid, the outlet temperature of a main heater and the outlet temperature of a compensation heater supplied by a mains power grid, the set heating power is combined, the PID control adjusting power is calculated according to the energy conservation law, and the PID control compensation power is obtained, wherein the calculation formula is as follows:

wherein Q is the heat gain of the circulating carrier fluid after flowing through the heater, and w;the mass flow of the circulating carrier fluid is kg/s; c_pThe constant pressure specific heat capacity of the circulating carrier fluid is kJ/kg-C; t is_outThe outlet temperature of the circulating carrier fluid in the thermal response tester, C; t is_inTo circulate the carrier fluid at the inlet temperature of the thermal response tester, C.

3. The method for realizing constant power heating in the rock-soil in-situ thermal response test according to claim 2, wherein the dual feedback adjustment method comprises the following steps:

and feeding back the PID control regulation power based on the outlet temperature of the compensation heater and feeding back the PID control regulation power based on the outlet temperature of the main heater supplied by the mains supply power grid.

4. The method for realizing constant power heating in the rock-soil in-situ thermal response test according to claim 1, wherein the step of dividing the obtained rock-soil in-situ thermal response multiple original data into a base power provided by a commercial power grid and a PID control regulation power comprises the following steps:

setting the basic power directly provided by a commercial power grid as 70-90% of the total heating power, and regulating the power part by PID control of 30-10% of the residual total heating power, wherein the total heating power is the sum of various acquired rock-soil in-situ thermal response original data.

Technical Field

The application relates to the technical field of shallow geothermal energy development and application, in particular to a method for realizing constant power heating in rock and soil in-situ thermal response test.

Background

In the existing rock-soil in-situ TRT thermal response test, the requirement on the constant heating power of a circulating carrier fluid in the thermal response test is usually realized by adopting a resistance heating mode of a pure resistive load. The principle for achieving constant heating power is based on a power calculation formula of a pure resistive load.

In general, the fluctuating electric heater power can also be approximated as a constant power when the supply voltage does not fluctuate too much. However, when the power supply voltage fluctuation exceeds a certain range, the fluctuation power of the electric heater cannot meet the requirement of constant heating power in the rock-soil in-situ TRT thermal response test, errors are brought to the test result, and the test is invalid when the fluctuation power is serious.

In engineering practice, a power supply for rock-soil in-situ TRT thermal response test usually comes from a mains supply power grid, and in order to reduce or reduce the influence of heating power fluctuation of a heater on a test result, people usually connect the mains supply into a voltage stabilizer, and connect a power supply stabilized by the voltage stabilizer with a TRT tester, so that constant heating power of the electric heater in the thermal response test process is ensured. On one hand, because the heating power of the TRT thermal response test is usually within the range of 5kw to 10kw, when the voltage stabilizer is adopted to provide constant power voltage, the requirement on the capacity of the voltage stabilizer is very high, and the voltage stabilizer with overlarge capacity will influence the portability and mobility of the TRT thermal response test equipment, so that the TRT thermal response test equipment is not beneficial to popularization and application in engineering practice; on the other hand, the rock-soil in-situ TRT thermal response test requires continuous and continuous operation for at least 48 hours, the fluctuation of a mains supply power grid is generally periodic, the difference between the highest voltage and the lowest voltage is large, and if the requirement of strictly meeting the constant voltage output of high power in the TRT test is to be met, the capacity and the requirement of the voltage stabilizer are very high. Therefore, the voltage stabilizer is adopted to provide a stable power supply for the geotechnical TRT thermal response test, and the solution is faced with a plurality of practical difficulties in engineering practice, thereby seriously restricting the application of the constant power heating mode in the TRT thermal response test engineering practice.

Disclosure of Invention

The application aims to provide a method for realizing constant power heating in rock-soil in-situ thermal response test, and the problem of non-constant power caused by mains supply voltage fluctuation in the rock-soil in-situ thermal response test is effectively solved by utilizing the advantages of high precision, strong adaptive capacity, high response speed and the like of PID control.

In order to achieve the above object, the present application provides a method for achieving constant power heating in a rock-soil in-situ thermal response test, comprising the following steps:

dividing the obtained rock-soil in-situ thermal response multiple original data into basic power and PID control regulation power provided by a mains supply power grid;

based on a double feedback regulation method, calculating the PID control regulation power according to an energy conservation law to obtain the PID control compensation power;

and the PID control compensation power is used as a control input signal of a pulse width modulation technology, and real-time control of the PID compensation power part is realized by dynamically adjusting the PWM output duty ratio.

The method comprises the following steps of calculating the PID control regulated power according to the energy conservation law based on a dual feedback regulation method to obtain the PID control compensation power, wherein the method comprises the following steps:

according to the measurement of the inlet temperature of the circulating carrier fluid, the outlet temperature of a main heater and the outlet temperature of a compensation heater supplied by a mains power grid, the set heating power is combined, the PID control adjusting power is calculated according to the energy conservation law, and the PID control compensation power is obtained, wherein the calculation formula is as follows:

wherein Q is the heat gain of the circulating carrier fluid after flowing through the heater, and w;the mass flow of the circulating carrier fluid is kg/s; c_pThe constant pressure specific heat capacity of the circulating carrier fluid is kJ/kg-C; t is_outThe outlet temperature of the circulating carrier fluid in the thermal response tester, C; t is_inTo circulate the carrier fluid at the inlet temperature of the thermal response tester, C.

Wherein, the dual feedback regulation method comprises the following steps:

and feeding back the PID control regulation power based on the outlet temperature of the compensation heater and feeding back the PID control regulation power based on the outlet temperature of the main heater supplied by the mains supply power grid.

The method comprises the following steps of dividing the obtained rock-soil in-situ thermal response multiple original data into basic power provided by a mains supply power grid and PID control regulation power, wherein the method comprises the following steps:

setting the basic power directly provided by a commercial power grid as 70-90% of the total heating power, and regulating the power part by PID control of 30-10% of the residual total heating power, wherein the total heating power is the sum of various acquired rock-soil in-situ thermal response original data.

According to the method for realizing constant power heating in rock-soil in-situ thermal response test, multiple kinds of obtained original data of rock-soil in-situ thermal response are divided into basic power and PID control regulation power provided by a mains supply power grid; based on a double feedback regulation method, calculating the PID control regulation power according to an energy conservation law to obtain the PID control compensation power; the PID control compensation power is used as a control input signal of a pulse width modulation technology, real-time control over the PID compensation power part is achieved through dynamic adjustment of PWM output duty ratio, and the problem of inconstant power caused by mains supply voltage fluctuation in rock-soil in-situ thermal response test is effectively solved by utilizing the advantages of high precision, strong self-adaptive capacity, high response speed and the like of PID control.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic step diagram of a method for realizing constant power heating in a rock-soil in-situ thermal response test provided by the application.

Fig. 2 is an exploded schematic view of the cyclic carrier fluid heating power provided herein.

Fig. 3 is a basic principle of PID control compensation heating provided by the present application.

Fig. 4 is a control schematic diagram of PID compensated heating provided by the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

In the description of the present application, it is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which is for convenience and simplicity of description, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, is not to be considered as limiting. Further, in the description of the present application, "a plurality" means two or more unless specifically defined otherwise.

Equivalent Thermal physical parameters of the rock and soil are usually obtained by a so-called rock and soil in-situ Thermal Response Test (Thermal Response Test), in which continuous and constant heat release is required to be carried out on a single-U or double-U underground buried pipe heat exchanger through circulating carrier fluid, the temperature change of the circulating carrier fluid at the inlet and the outlet of a buried pipe with time under a given flow rate is measured and recorded, and the equivalent Thermal physical parameters of the rock and soil around the buried pipe are calculated according to a line heat source model. Because the power of the circulating carrier fluid which is required by the line heat source model to flow in the buried pipe and exchange heat with the rock soil must be constant, the circulating carrier fluid needs to be heated continuously and constantly from the outside in the rock soil in-situ TRT thermal response test process. The application aims to innovate and improve the realization of a constant power heating method for a circulating carrier fluid in a rock-soil in-situ TRT thermal response test.

Referring to fig. 1, the present application provides a method for implementing constant power heating in a rock-soil in-situ thermal response test, comprising the following steps:

s101, dividing the obtained rock-soil in-situ thermal response multiple original data into basic power provided by a mains supply power grid and PID control regulation power.

Specifically, in order to effectively reduce the output power of the PID control part, the total heating power set on the circulating carrier fluid is decomposed, as shown in fig. 2, the total heating power is decomposed into a basic power part and a PID control regulation power part provided by the utility grid. According to the regulation of national standard GB/T12325-. The distribution proportion can ensure that the total output power is kept constant, the output power of the PID control part can be reduced to the maximum extent while the maximum heating basic power is provided by fully utilizing a mains supply power grid, the cost of the PID control circuit is reduced to the maximum extent, and the reliability and the sensitivity of the PID control part are improved.

And S102, calculating the PID control regulated power according to the energy conservation law based on a dual feedback regulation method to obtain the PID control compensation power.

Specifically, in the operation process, although the basic power provided by the utility grid fluctuates with the utility voltage, the PID control adjustment power can calculate the PID control compensation power in real time according to the measurement of the inlet temperature of the circulating carrier fluid, the outlet temperature of the main heater supplied with power by the utility grid and the outlet temperature of the compensation heater, in combination with the heating power set by the user, and according to the formula (1).

On the circulating carrier side of the rock-soil TRT thermal response test, according to energy conservation, the heat obtained by the circulating carrier in the heater can be obtained as follows:

in the above formula, Q is the heat gain of the circulating carrier fluid after flowing through the heater, w;the mass flow of the circulating carrier fluid is kg/s; c_pThe constant pressure specific heat capacity of the circulating carrier fluid is kJ/kg-C; t is_outThe outlet temperature of the circulating carrier fluid in the thermal response tester, C; t is_inTo circulate the carrier fluid at the inlet temperature of the thermal response tester, C.

In order to achieve constant power heating of the circulating carrier fluid, it can be seen from the above equation: since the specific heat capacity at constant pressure is almost constant over a range of temperatures, at a given cycle the carrier fluid mass flow (i.e.:) Under the condition, the temperature difference between the inlet and the outlet of the circulating carrier fluid is controlled to be a constant value. Therefore, the control of the constant heating power of the circulating carrier fluid can be converted into the control of the temperature difference of the inlet and the outlet of the carrier fluid.

And S103, taking the PID control compensation power as a control input signal of a pulse width modulation technology, and realizing real-time control of the PID compensation power part by dynamically adjusting the PWM output duty ratio.

Specifically, the control input signal is used as a control input signal of a Pulse Width Modulation (PWM) technology, and a PWM output duty ratio is dynamically adjusted to realize real-time control of a PID compensation power part, so as to ensure that the total power applied to a circulating carrier (including a basic power on a main heater and a compensation power on a compensation heater) is equal to a user set value, and realize constant power heating of the circulating carrier in a rock-soil in-situ thermal response test, as shown in fig. 3 and 4, wherein 1 is a main heater, 2 is a compensation heater, 3 is a test point power grid power supply 4 is a PID control compensation power supply, original data includes circulating carrier inlet temperature, circulating carrier mass flow and the like, the circulating carrier inlet temperature, the circulating carrier mass flow and the like are divided into a basic power and PID control regulation power provided by a mains power grid, PID control is input based on the total heating power set by a user, and the circulating carrier outlet temperature passing through the compensation heater and a main heater outlet fluid of the main heater are subjected to the PID control regulation power supply And the temperature is subjected to double feedback regulation, the temperature is output to a PWM (pulse-width modulation) modulated compensation power supply and then is transmitted to a compensation heater for calculation control, the outlet temperature of the circulating carrier fluid and the outlet of the circulating carrier fluid are output, and the compensation heater is also controlled by an autonomous heater of the circulating carrier fluid.

The invention is characterized in that:

1. decomposing the heating power applied to the circulating carrier fluid into a base power provided by the mains power supply (i.e., provided by the main heater) and a compensation power provided by the PID control compensation power supply (i.e., provided by the compensation heater);

2. converting the constant heating power into a constant heating temperature difference, and adopting PID (proportion integration differentiation) to control the compensation power in real time so that the sum of the compensation power and the basic power is equal to the heating power value set by a user;

3. the method effectively solves the problem of inconstant power caused by the fluctuation of mains supply voltage in the rock-soil in-situ thermal response test by fully utilizing the advantages of high precision, strong self-adaptive capability, high response speed and the like of PID control.

Advantageous effects

1. The control is simple, the reliability is high, and the volume of the whole system is small and easy to integrate and integrate due to the absence of a conventional voltage stabilizer with large volume and heavy weight, so that the device is suitable for the requirements of portability and light weight of the rock-soil in-situ TRT thermal response tester;

2. the PID control and PWM modulation technology is mature, the self-adaptive capacity is strong, the response speed of the control is easy to adjust, and the system implementation cost is low.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.