Cold storage space electric field intensity closed-loop control method and device

Abstract

The invention discloses a cold storage space electric field intensity closed-loop control method and device, and the method comprises the steps: arranging a plurality of radiation electrodes on a ceiling of a cold storage, and arranging a plurality of electric field intensity sensors in the cold storage in a distributed manner; utilizing a radiation electrode to excite radiation voltage, and utilizing an electric field intensity sensor to acquire sensor array data; based on sensor array data, generating a space field intensity distribution model by adopting a weighted average algorithm to obtain an electric field intensity control value; performing deviation calculation according to the electric field intensity control value and actually measured sensor array data to obtain a voltage regulation control quantity; and PID closed-loop adjustment is carried out on the plurality of radiation electrodes by using the voltage adjustment control quantity. By means of the scheme, the method has the advantages of being simple in logic, reliable in control and the like, and has high practical value and popularization value in the technical field of refrigeration house space electric field control.

Description

Technical Field

[0001] The invention relates to the technical field of electric field control in cold storage space, in particular to a closed-loop control method and device for electric field intensity in cold storage space. Background Art

[0002] The cold storage space electric field is a technology that uses high-voltage electric field or low-temperature plasma electric field to achieve food preservation. Its core principle is to create a specific electric field environment in the cold storage to produce ions, negative ions and trace ozone, thereby achieving sterilization, inhibiting microbial growth, and regulating food physiological metabolism. Among them, the reasons why the cold storage space electric field needs to adjust the electric field strength are mainly the following:

[0003] First, adapt to the preservation needs of different foods; for example, fruits and vegetables are less sensitive to electric field strength, while meat and seafood have a narrower adaptability to electric field strength. Adjusting the electric field strength can ensure that each food can be preserved in the most suitable electric field environment, avoiding the preservation effect affected by too high or too low electric field strength. Second, optimize the preservation effect; the electric field strength will affect the key indicators of the preservation effect, such as microbial inhibition, respiration regulation, and ethylene release inhibition. Third, *control ice crystal growth; in a low temperature environment, the electric field strength has a significant effect on the formation and growth of ice crystals. Appropriate electric field strength can inhibit the growth of ice crystals and reduce the damage of ice crystals to the cell structure of food, thereby improving the preservation quality of food. Fourth, avoid the safety risks of electric fields to equipment and personnel; excessive electric field strength may cause the insulation performance of equipment to decline, and even cause electrical breakdown. In addition, excessive electric field strength may also produce corona discharge, which not only wastes energy, but also may cause safety hazards to operators. Fifth, energy saving and economy; appropriate electric field strength can reduce energy consumption while ensuring the preservation effect. Too high an electric field strength will not only increase energy consumption, but may also shorten the service life of the equipment. In summary, the purpose of adjusting the electric field strength in the cold storage space is to better meet the preservation needs of different foods, optimize the preservation effect, ensure the safety of equipment and personnel, and strike a balance between economy and preservation effect.

[0004] At present, the existing technologies, such as the public technology of "Patent Publication No. CN116280749A, named a refrigerated container with space electric field preservation technology", the public technology of "Patent Publication No. CN203787768U, named a space electric field generating device", and the public technology of "Patent Publication No. CN221152780U, named a mobile space electric field preservation equipment", etc., all adopt open-loop control mode and do not have the multi-node perception capability of space electric field. The main defects are as follows: First, the field strength stability is poor: the existing traditional electric field generating device cannot perceive the changes in the environmental electric field in real time, resulting in the field strength shifting with the fluctuation of temperature and humidity, affecting the antibacterial preservation effect. Second, insufficient frequency tracking: when the mains interference occurs or the load changes due to temperature changes, the electric field output frequency is easy to lose lock, resulting in uneven distribution of electric field energy and disorderly and irregular electric field control. Third, it cannot achieve optimal control energy efficiency: the fixed voltage output mode of the existing space electric field generating device has energy waste problems and does not meet the energy-saving requirements of cold storage. The existing public document patents all belong to an electric field regulating device based on a single-point sensor, which lacks a multi-point collaborative feedback mechanism and control mechanism, and is difficult to cover the requirements of large-space field intensity balance.

[0005] Therefore, it is urgent to propose a closed-loop control method and device for the electric field intensity in the cold storage space with simple logic and reliable control. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a closed-loop control method and device for electric field intensity in cold storage space. The technical solution adopted by the present invention is as follows:

[0007] A closed-loop control method for electric field intensity in a cold storage space comprises the following steps:

[0008] Several radiation electrodes are arranged on the ceiling of the cold storage, and several electric field strength sensors are distributed in the cold storage;

[0009] The radiation electrode is used to excite the radiation voltage, and the electric field intensity sensor is used to collect and obtain the sensor array data;

[0010] Based on the sensor array data, a spatial field intensity distribution model is generated by using a weighted average algorithm to obtain an electric field intensity control value;

[0011] The voltage regulation control amount is obtained by calculating the deviation between the electric field intensity control value and the measured sensor array data;

[0012] The voltage regulation control quantity is used to perform PID closed-loop regulation on several radiation electrodes.

[0013] Furthermore, the radiation electrodes and electric field strength sensors are arranged in a grid pattern, and the distance between adjacent electrodes is 2 m.

[0014] Furthermore, the method of generating a spatial field intensity distribution model based on the sensor array data and using a weighted average algorithm to obtain an electric field intensity control value includes the following steps:

[0015] Obtaining an electric field strength data set of one of the electric field strength sensors within a time period of t, and evenly dividing the electric field strength data set into segments, and obtaining an average value of the electric field strength of the electric field strength sensor within a time period of t; t is a natural number;

[0016] Traverse and obtain the average value of the electric field strength of the remaining electric field strength sensors within the time t; and form n stable electric field values; wherein n is the number of electric field strength sensors; the electric field strength data sets of the n electric field strength sensors within the time t together form the sensor array data;

[0017] The n stable electric field values ​​are sorted in ascending order, and weighted average calculation is performed to obtain the electric field intensity control value.

[0018] Furthermore, the step of sorting the n stable electric field values ​​in ascending order and performing weighted average calculation to obtain the electric field intensity control value comprises the following steps:

[0019] Sort the n stable electric field values ​​and assign weights in reverse order of natural numbers;

[0020] The weights are normalized and the sum S of all weights is calculated, which is expressed as:

[0021]

[0022] Among them, w i represents the weighted value, k represents the weight sequence;

[0023] Get the weighted average A V , whose expression is:

[0024]

[0025] Among them, d i represents the electric field strength data value measured for the i-th time;

[0026] The weighted average A V As the electric field strength control value.

[0027] Furthermore, the method of performing PID closed-loop regulation on a plurality of radiation electrodes by using the voltage regulation control amount comprises the following steps:

[0028] Incremental PI control is adopted, which is expressed as:

[0029] Δu(k)=u(k)-u(k-1)=K P ×[e(k)-e(k-1)]+K I ×e(k)

[0030]

[0031] Among them, u(k) represents the PI control amount at the kth moment; u(k-1) represents the PI control amount at the k-1th moment; K P Indicates the proportional control coefficient; K I represents the integral control coefficient; e(k) represents the field strength error value at the kth moment; e(k-1) represents the field strength error value at the k-1th moment; e(n) represents the field strength error value at the nth moment; Δu(k) represents the control increment parameter.

[0032] A device adopting a closed-loop control method of electric field intensity in cold storage space, comprising:

[0033] Several radiation electrodes are arranged on the ceiling of the cold storage to stimulate radiation voltage;

[0034] Several electric field strength sensors are distributed in the cold storage, and sensor array data is obtained;

[0035] The high-voltage electric field generating module is electrically connected to several radiating electrodes and several electric field strength sensors to obtain sensor array data, and a weighted average algorithm is used to generate a spatial field strength distribution model to obtain an electric field strength control value; a deviation is calculated based on the electric field strength control value and the measured sensor array data to obtain a voltage regulation control amount; and the voltage regulation control amount is used to perform PID closed-loop regulation on several radiating electrodes.

[0036] Furthermore, the high-voltage electric field generating module includes an AC-DC conversion module, a closed-loop control circuit, a boost circuit, a power switching circuit and a drive circuit; the AC-DC conversion module is externally connected to the AC mains and performs AC-DC conversion; the AC-DC conversion module is connected to the closed-loop control circuit, the boost circuit, the power switching circuit and the drive circuit.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The present invention uses sensor array data and a weighted average algorithm to generate a spatial field intensity distribution model to obtain an electric field intensity control value, which can obtain relatively accurate spatial radiation field intensity correction data.

[0039] (2) The present invention calculates the deviation between the electric field strength control value and the measured sensor array data to obtain the voltage regulation control quantity, and uses the voltage regulation control quantity to perform PID closed-loop regulation on several radiation electrodes. The advantage of this is that the control accuracy of the radiation voltage is more accurate and stable.

[0040] (3) The present invention divides the electric field strength data set of any electric field strength sensor within time t into uniform intervals, and obtains the average value of the electric field strength of the electric field strength sensor within time t, thereby ensuring the accuracy and reliability of the collected data and effectively avoiding interference from data distortion or mutation.

[0041] (4) The present invention sorts n stable electric field values ​​in ascending order, performs weighted average calculation, and uses natural numbers to allocate weights in reverse order, which can obtain dynamic electric field regulation control parameters that are close to spatially balanced distribution.

[0042] (5) The present invention adopts incremental PI control, which has the advantage that the continuous accumulation of measurement errors is eliminated, the calculated value is only related to the three most recent sampling values, the data is easy to process, and the oscillation impact of the control process is small.

[0043] In summary, the present invention has the advantages of simple logic and reliable control, and has high practical value and promotion value in the field of cold storage space electric field control technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope of protection. For those skilled in the art, other related drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 It is a schematic diagram of the layout of the radiation electrode, electric field strength sensor and high-voltage electric field generating module of the present invention.

[0046] Figure 2 It is a schematic diagram of the principle of the high voltage electric field generating module of the present invention.

[0047] Figure 3 It is a schematic diagram of PID control of the present invention.

[0048] Figure 4 It is a logic flow chart of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of this application clearer, the present invention is further described below in conjunction with the accompanying drawings and embodiments, and the embodiments of the present invention include but are not limited to the following embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0050] In this embodiment, the term "and / or" is merely a term used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0051] The terms "first" and "second" in the description and claims of this embodiment are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0052] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0053] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0054] like Figures 1 to 4As shown, this embodiment provides a closed-loop control method and device for the electric field intensity of a cold storage space, which is arranged on the ceiling of the cold storage to excite the radiation voltage; several electric field intensity sensors are distributed in the cold storage, and the sensor array data is obtained. In addition, the high-voltage electric field generation module includes an AC-DC conversion module, a closed-loop control circuit, a boost circuit, a power switch circuit and a drive circuit; the AC-DC conversion module is externally connected to the AC mains and performs AC-DC conversion; the AC-DC conversion module is connected to the closed-loop control circuit, the boost circuit, the power switch circuit and the drive circuit. In this embodiment, the AC power supply input from the AC-DC conversion module is AC / DC converted, which is used to control the power switch circuit and the drive circuit respectively. This embodiment designs PWM pulse width modulation to control the power switch circuit to generate a high-voltage AC voltage signal with a set amplitude and frequency, and then generates a spatial electric field through the radiation electrode. In use, parameters (such as the voltage amplitude and frequency corresponding to the preservation) are preset according to the object to be preserved, which belongs to conventional means and will not be repeated here.

[0055] The closed-loop control method of the electric field intensity in the cold storage space of this embodiment includes the following steps:

[0056] In the first step, the radiation electrode is used to excite the radiation voltage, and the electric field strength sensor is used to collect and obtain the sensor array data.

[0057] The second step is to generate a spatial field intensity distribution model based on the sensor array data and use a weighted average algorithm to obtain an electric field intensity control value. This includes:

[0058] (11) Obtain an electric field strength data set of one of the electric field strength sensors within a time period of t, and divide the electric field strength data set into evenly spaced intervals to obtain an average value of the electric field strength of the electric field strength sensor within a time period of t; wherein t is a natural number.

[0059] (12) Traverse and obtain the average electric field strength of the remaining electric field strength sensors within time t; and form n stable electric field values; wherein n is the number of electric field strength sensors; the electric field strength data sets of the n electric field strength sensors within time t together constitute the sensor array data.

[0060] (13) Sort the n stable electric field values ​​in ascending order, and perform weighted average calculation to obtain the electric field strength control value. Among them, the n stable electric field values ​​are sorted, and the weights are assigned in reverse order of natural numbers. That is, the weights are assigned to the sorted data, and the weights are required to be from large to small. The weights are assigned in reverse order of natural numbers, that is, the weight of the i-th data (index starts from 0) is w i =ni. In this way, the weight of the smallest data is n at most, and then decreases in sequence, and the weight of the largest data is 1.

[0061] The weights are normalized and the sum S of all weights is calculated, which is expressed as:

[0062]

[0063] Among them, w i represents the weighted value, and k represents the weight sequence.

[0064] Get the weighted average A V , whose expression is:

[0065]

[0066] Among them, d i Represents the electric field strength data value measured for the i-th time.

[0067] The weighted average A V As the electric field strength control value (ie, the desired field strength).

[0068] The third step is to calculate the deviation between the electric field strength control value and the measured sensor array data (ie, the actual field strength) to obtain the voltage regulation control quantity, and use the voltage regulation control quantity to perform PID closed-loop regulation on several radiation electrodes.

[0069] Here, incremental PI control is adopted, which is expressed as:

[0070] Δu(k)=u(k)-u(k-1)=K P ×[e(k)-e(k-1)]+K I ×e(k)

[0071]

[0072] Among them, u(k) represents the PI control amount at the kth moment; u(k-1) represents the PI control amount at the k-1th moment; K P Indicates the proportional control coefficient; K I represents the integral control coefficient; e(k) represents the field strength error value at the kth moment; e(k-1) represents the field strength error value at the k-1th moment; e(n) represents the field strength error value at the nth moment; Δu(k) represents the control increment parameter.

[0073] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any changes that adopt the design principles of the present invention and are made through non-creative labor on this basis should fall within the protection scope of the present invention.

Claims

1. A closed-loop control method for electric field intensity in cold storage space, characterized in that: The following steps are involved: Several radiation electrodes are arranged on the ceiling of the cold storage, and several electric field strength sensors are distributed in the cold storage; The radiation electrode is used to excite the radiation voltage, and the electric field intensity sensor is used to collect and obtain the sensor array data; Based on the sensor array data, a spatial field intensity distribution model is generated by using a weighted average algorithm to obtain an electric field intensity control value; The voltage regulation control amount is obtained by calculating the deviation between the electric field intensity control value and the measured sensor array data; The voltage regulation control quantity is used to perform PID closed-loop regulation on several radiation electrodes.

2. A closed-loop control method for electric field intensity in cold storage space according to claim 1, characterized in that: The radiation electrodes and electric field strength sensors are arranged in a grid pattern, and the distance between adjacent electrodes is 2 m.

3. A closed-loop control method for electric field intensity in cold storage space according to claim 1, characterized in that: The method of generating a spatial field intensity distribution model based on the sensor array data and using a weighted average algorithm to obtain an electric field intensity control value includes the following steps: Obtaining an electric field strength data set of one of the electric field strength sensors within a time period of t, and evenly dividing the electric field strength data set into segments, and obtaining an average value of the electric field strength of the electric field strength sensor within a time period of t; t is a natural number; Traverse and obtain the average value of the electric field strength of the remaining electric field strength sensors within the time t; and form n stable electric field values; wherein n is the number of electric field strength sensors; the electric field strength data sets of the n electric field strength sensors within the time t together form the sensor array data; The n stable electric field values ​​are sorted in ascending order, and weighted average calculation is performed to obtain the electric field intensity control value.

4. A closed-loop control method for electric field intensity in cold storage space according to claim 3, characterized in that: The method of sorting the n stable electric field values ​​in ascending order and performing weighted average calculation to obtain the electric field intensity control value comprises the following steps: Sort the n stable electric field values ​​and assign weights in reverse order of natural numbers; The weights are normalized and the sum S of all weights is calculated, which is expressed as: Among them, w i represents the weighted value, k represents the weight sequence; Get the weighted average A V , whose expression is: Among them, d i represents the electric field strength data value measured for the i-th time; The weighted average A V As the electric field strength control value.

5. A closed-loop control method for electric field intensity in cold storage space according to claim 3, characterized in that: The method of using the voltage regulation control amount to perform PID closed-loop regulation on a plurality of radiation electrodes comprises the following steps: Incremental PI control is adopted, which is expressed as: Δu(k)=u(k)-u(k-1)=K P ×[e(k)-e(k-1)]+K I ×e(k) Among them, u(k) represents the PI control amount at the kth moment; u(k-1) represents the PI control amount at the k-1th moment; K P Indicates the proportional control coefficient; K I represents the integral control coefficient; e(k) represents the field strength error value at the kth moment; e(k-1) represents the field strength error value at the k-1th moment; e(n) represents the field strength error value at the nth moment; Δu(k) represents the control increment parameter.

6. A device using the closed-loop control method of electric field intensity in cold storage space according to any one of claims 1 to 5, characterized in that: include: Several radiation electrodes are arranged on the ceiling of the cold storage to stimulate radiation voltage; Several electric field strength sensors are distributed in the cold storage, and sensor array data is obtained; The high-voltage electric field generating module is electrically connected to several radiating electrodes and several electric field strength sensors to obtain sensor array data, and a weighted average algorithm is used to generate a spatial field strength distribution model to obtain an electric field strength control value; a deviation is calculated based on the electric field strength control value and the measured sensor array data to obtain a voltage regulation control amount; and the voltage regulation control amount is used to perform PID closed-loop regulation on several radiating electrodes.

7. The device using the closed-loop control method of the electric field intensity in the cold storage space according to claim 6 is characterized in that: The high-voltage electric field generating module includes an AC-DC conversion module, a closed-loop control circuit, a boost circuit, a power switch circuit and a drive circuit; the AC-DC conversion module is externally connected to the AC mains and performs AC-DC conversion; the AC-DC conversion module is connected to the closed-loop control circuit, the boost circuit, the power switch circuit and the drive circuit.

Images