CN118066135A - Automatic control system and automatic control method for steam compressor - Google Patents

Abstract

The application provides an automatic control system and an automatic control method of a vapor compressor, wherein the system comprises the following components: the state monitoring module is used for acquiring state information of the steam compressor; the work control module is used for determining the expected working state of the vapor compressor based on the evaporation task execution instruction of the user, controlling the vapor compressor to start and execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and the state information of the vapor compressor, controlling the vapor compressor to enter a standby state, and being capable of realizing full-automatic control of the vapor compressor and avoiding faults such as abnormal tripping caused by manual operation.

Description

Automatic control system and automatic control method for steam compressor

Technical Field

The application relates to the technical field of compressor monitoring, in particular to an automatic control system and an automatic control method of a steam compressor.

Background

Vapor compressors are critical devices for heat recovery systems to raise the temperature and pressure of the vapor produced by compression. The function is to raise the temperature of low pressure (or low temperature) steam to meet the temperature and pressure requirements of the process or engineering.

In the traditional control of the steam compressor, the start-stop adjustment and the abnormal working condition treatment of the steam compressor are manually operated by technicians, and the adjustment mode is complex and easy to cause misoperation, so that the faults such as abnormal tripping of the steam compressor are caused.

Disclosure of Invention

The application provides an automatic control system and an automatic control method of a steam compressor, which are used for realizing full-automatic control of the steam compressor and avoiding faults such as abnormal tripping caused by manual operation.

The present application provides an automatic control system of a vapor compressor, the system comprising:

The state monitoring module is used for acquiring state information of the steam compressor;

The work control module is used for determining the expected working state of the vapor compressor based on the evaporation task execution instruction of the user, and controlling the vapor compressor to start to execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and the state information of the vapor compressor so as to control the vapor compressor to enter the standby state.

The application also provides an automatic control method of the steam compressor, which is applied to the working control module of the automatic control system of the steam compressor, and comprises the following steps:

Determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state;

starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor;

Determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters;

And controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

According to the automatic control method of the vapor compressor provided by the application, the expected inlet pressure and the expected outlet pressure of the vapor compressor are determined in response to the evaporation task execution instruction of a user, and the automatic control method concretely comprises the following steps:

Responding to an evaporation task execution instruction of a user, and acquiring job indication information in the evaporation task execution instruction; the operation indication information comprises names of materials to be evaporated;

Determining the evaporation temperature and the preheating temperature of the material to be evaporated based on the name of the material to be evaporated, determining the evaporation rate range corresponding to different material flow rates based on the preheating temperature and the evaporation temperature of the material to be evaporated and the design parameters of an evaporator in a current evaporation system, and determining the inlet temperature range and the inlet pressure range of a vapor compressor corresponding to the evaporation rate range based on the temperature and the pressure loss model of the current evaporation system;

Determining a desired inlet pressure of the vapor compressor and a corresponding optimal material flow rate based on a comparison of the vapor compressor inlet pressure range corresponding to the evaporation rate range and a design inlet pressure of the vapor compressor;

The desired outlet temperature of the vapor compressor is determined based on the evaporation temperature of the material to be evaporated, and the desired outlet pressure of the vapor compressor is determined based on the desired outlet temperature of the vapor compressor and the vapor compressor inlet temperature corresponding to the optimal material flow rate.

According to the automatic control method of the vapor compressor provided by the application, the design parameters of the evaporator comprise the heat transfer area and the heat transfer coefficient of the evaporator, and correspondingly, the evaporation rate range corresponding to different material flow rates is determined based on the preheating temperature and the evaporation temperature of the material to be evaporated and the design parameters of the evaporator in the current evaporation system, and the method specifically comprises the following steps:

Determining heat transfer amounts corresponding to different material flow rates based on the preheating temperature, the evaporating temperature and the heat transfer area and the heat transfer coefficient of an evaporator in a current evaporating system of the material to be evaporated;

And determining the evaporation rate range corresponding to the different material flow rates based on the heat transfer quantity corresponding to the different material flow rates and the evaporation latent heat of the material to be evaporated.

According to the automatic control method of the vapor compressor provided by the application, the method for determining the expected inlet pressure of the vapor compressor based on the comparison result of the vapor compressor inlet pressure range corresponding to the evaporation rate range and the design inlet pressure of the vapor compressor specifically comprises the following steps:

When the design inlet pressure of the vapor compressor is in the vapor compressor inlet pressure range corresponding to the evaporation rate range, taking the design inlet pressure as the expected inlet pressure of the vapor compressor;

when the design inlet pressure of the vapor compressor is not in the vapor compressor inlet pressure range corresponding to the evaporation rate range, the target vapor compressor inlet pressure with the smallest difference from the design inlet pressure is taken as the expected inlet pressure of the vapor compressor.

According to the automatic control method of the vapor compressor provided by the application, the vapor compressor is controlled to enter a starting preparation state, and the method specifically comprises the following steps:

monitoring and adjusting state information of a target part of the steam compressor based on preset starting conditions of the steam compressor; wherein, the starting condition of the steam compressor is as follows: the oil temperature and the oil pressure of the lean oil station are not lower than preset thresholds; the opening and closing states of the air compensating valve and the anti-surge valve are that the air compensating valve is closed and the anti-surge valve is opened; the working state of the motor temperature control system is that the cooling system works, the heating system is closed, and the frequency converter is ready.

According to the automatic control method of the vapor compressor provided by the application, the production starting conditions comprise vapor compressor starting conditions and associated equipment state conditions, and the associated equipment state conditions comprise: the evaporator starts feeding; correspondingly, the main motor frequency of the vapor compressor is controlled based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor, and the main motor frequency comprises the following specific components:

determining a current demand compression ratio based on a real-time inlet pressure and a real-time inlet temperature of the vapor compressor;

A demand frequency of the main motor is determined based on the current demand compression ratio, and the frequency of the main motor is adjusted to the demand frequency.

According to the automatic control method of the vapor compressor provided by the application, the basic state parameters comprise: the temperature of the motor bearing, the temperature of the motor stator winding, the oil supply temperature and pressure of the thin oil station, the temperature of the speed increasing box bearing and the vibration amplitude of the speed increasing box bearing; the compression state parameters include: vapor compressor inlet pressure and vapor compressor outlet pressure;

The abnormal working conditions comprise basic state abnormality and compression state abnormality; correspondingly, the method for monitoring and processing the abnormal working condition based on the target state information of the steam compressor specifically comprises the following steps:

monitoring and processing basic state anomalies based on basic state parameters of the vapor compressor; meanwhile, compression state abnormality monitoring and processing are performed based on compression state parameters of the vapor compressor.

According to the automatic control method of the vapor compressor provided by the application, the compression state abnormality monitoring and processing are carried out based on the compression state parameters of the vapor compressor, and the method concretely comprises the following steps:

Step S1, determining whether the inlet pressure of the vapor compressor is abnormal or not based on the ratio of the inlet pressure of the vapor compressor to the expected inlet pressure, if so, executing step S2, otherwise, jumping to execute step S3;

step S2, adjusting the opening of the air compensating valve until the inlet pressure of the compressor returns to normal, and executing step S3;

step S3, based on the comparison result of the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor and the expected value, determining whether the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is abnormal, if yes, executing step S4, otherwise, jumping to execute step S5;

step S4, adjusting the anti-surge valve to a first opening degree until the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is recovered to be normal, and executing step S5;

step S5, determining whether the operation current of the steam compressor fluctuates or not based on the sampling value of the operation current of the steam compressor at preset time intervals, if so, adjusting the anti-surge valve to a second opening degree until the operation current of the steam compressor does not fluctuate, executing step S6, otherwise, directly executing step S6; wherein the second opening is larger than the first opening;

and S6, closing the anti-asthma valve, and jumping to execute the step S1.

According to the automatic control method of the vapor compressor, provided by the application, when the ratio of the vapor compressor inlet pressure to the expected inlet pressure is lower than a first preset percentage and lasts for a first preset duration, the abnormality of the vapor compressor inlet pressure is determined;

determining that the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is abnormal if the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is greater than a second preset percentage of the desired value;

And determining the fluctuation of the operation current of the steam compressor under the working condition that the difference value of the operation current sampling values of the adjacent steam compressors exceeds a preset fluctuation threshold value and lasts for a second preset duration.

The application provides an automatic control system and an automatic control method of a vapor compressor, wherein the system comprises the following components: the state monitoring module is used for acquiring state information of the steam compressor; the work control module is used for determining the expected working state of the vapor compressor based on the evaporation task execution instruction of the user, controlling the vapor compressor to start and execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and the state information of the vapor compressor, controlling the vapor compressor to enter a standby state, and being capable of realizing full-automatic control of the vapor compressor and avoiding faults such as abnormal tripping caused by manual operation.

Drawings

In order to more clearly illustrate the application or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an automatic control system for a vapor compressor according to the present application;

FIG. 2 is a schematic flow chart of an automatic control method of a vapor compressor provided by the application;

FIG. 3 is a schematic illustration of a determined flow path for a desired inlet pressure and a desired outlet pressure of a vapor compressor provided by the present application;

FIG. 4 is a schematic diagram of a process flow for monitoring and handling compression state anomalies provided by the present application;

FIG. 5 is a schematic view of the structure of an automatic control device of a vapor compressor according to the present application;

fig. 6 is a schematic structural diagram of an electronic device provided by the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Fig. 1 is a schematic structural diagram of an automatic control system of a vapor compressor according to the present application, as shown in fig. 1, the system includes:

A state monitoring module 101, configured to obtain state information of the vapor compressor;

The operation control module 102 is configured to determine an expected operation state of the vapor compressor based on an evaporation task execution instruction of a user, and control the vapor compressor to start to execute the evaporation task until the evaporation task is completed based on the expected operation state of the vapor compressor and state information of the vapor compressor, and control the vapor compressor to enter a standby state.

In particular, it is understood that the automatic control system of the vapor compressor according to the embodiments of the present application is used to automatically control the vapor compressor in the existing MVR (MECHANICAL VAPOR RECOMPRESSION ) system. The MVR system includes a preheater, an evaporator, a circulation pump, a separator, and a vapor compressor. The material to be evaporated is preheated by a preheater and then enters the evaporator for evaporation, secondary steam generated after evaporation enters the vapor compressor after entrained liquid drops are removed by the separator, the secondary steam enters the evaporator as heating steam after being compressed by the vapor compressor so as to reheat the material to be evaporated, the secondary steam is condensed and discharged as clean water, and meanwhile, the material is circularly fed into the evaporator by a circulating pump so as to be continuously evaporated and concentrated. The water in the material to be evaporated can be removed by the circulation and the repeated operation, thereby achieving the purpose of concentration or crystallization. It should be noted that, in particular, the existing MVR system refers to an MVR system in which each device type is already fixed (hereinafter referred to as a given MVR system). The prior art generally assembles the MVR system based on the requirements of the evaporation tasks (i.e. performs the selection of the evaporator, the vapor compressor, etc. to form the complete MVR system), which will result in frequent adjustment of the device model in the MVR system or provision of multiple MVR systems in order to meet the requirements of different evaporation tasks, which will greatly increase the production cost and reduce the production efficiency. Aiming at the problem, the automatic control system of the vapor compressor provided by the embodiment of the application aims to realize the full-automatic control of the evaporation process flow of the vapor compressor in the given MVR system, so that the given MVR system realizes automatic production on the basis of matching different evaporation task requirements.

More specifically, in order to realize full-automatic control of the evaporation process flow of the vapor compressor in the given MVR system, the embodiment of the application obtains the state information of the vapor compressor through the state monitoring module, and it can be understood that the state monitoring module comprises sensor sub-modules arranged at each part of the vapor compressor and corresponding monitoring data collecting sub-modules, each sensor sub-module is used for measuring the state data of the vapor compressor, and the monitoring data collecting sub-module is used for collecting the state data measured by each sensor sub-module. It is further understood that the state monitoring module further includes a state information transmission sub-module for actively or passively (i.e. after receiving the data transmission command, the operation is performed) transmitting the state information of the vapor compressor to the operation control module. Based on the above, the automatic control system provided by the embodiment of the application can accurately grasp the state information of the vapor compressor in the whole period in the evaporation process flow, thereby realizing the full-automatic refined control of the vapor compressor. Specifically, the work control module is used for determining an expected working state of the vapor compressor based on an evaporation task execution instruction of a user, and controlling the vapor compressor to start to execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and state information of the vapor compressor to control the vapor compressor to enter a standby state.

It will be appreciated that the desired operating conditions of the vapor compressor include a desired inlet pressure and a desired outlet pressure of the vapor compressor. In case the inlet pressure and the outlet pressure of the vapor compressor are constant (i.e. the compression ratio is constant), if the inlet temperature of the vapor compressor is known, the corresponding warming effect (i.e. the warming) can be directly determined. Based on the method, the optimal working state (namely, the expected working state, namely, the working state which is most matched with the evaporation task) of the vapor compressor can be determined based on the corresponding requirement of the evaporation task and the design parameters of each device in the evaporation system, and the vapor compressor is controlled to continuously work in the expected working state by combining the state information of the vapor compressor, so that the accurate and efficient execution of the evaporation task is ensured. It should be noted that, considering that in actual production, in order to ensure that the production efficiency is maximized, the interval time between the continuous evaporation tasks is shortened as much as possible, and the starting and the stopping of the vapor compressor are delayed for a long time (the time required for the rising and the falling of the frequency of the main motor of the vapor compressor), therefore, the frequent starting and stopping of the vapor compressor will reduce the production efficiency, and also affect the stability of the system, and bring surge risk. However, if the evaporation task execution instruction is not received after the vapor compressor enters the standby state for a preset downtime, the vapor compressor is controlled to enter the shutdown state so as to avoid energy waste.

It can be further understood that a user can release the evaporation task through a preset interaction interface of the evaporation task monitoring terminal or the work control module, and the work control module can determine the control time sequence and the control parameters of the MVR system according to the associated information of the evaporation task, and meanwhile, can automatically process abnormal working conditions. The evaporation task monitoring terminal can be an intelligent terminal such as a mobile phone or a computer, and the embodiment of the application is not particularly limited. The work control module may be built in the evaporation task monitoring terminal or may be disposed in a remote server, which is not particularly limited in the embodiment of the present application.

The application provides a system, comprising: the state monitoring module is used for acquiring state information of the steam compressor; the work control module is used for determining the expected working state of the vapor compressor based on the evaporation task execution instruction of a user, controlling the vapor compressor to start and execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and the state information of the vapor compressor, controlling the vapor compressor to enter a standby state, and realizing full-automatic control of the vapor compressor in a given MVR system, and realizing adaptation of different evaporation tasks while avoiding faults such as abnormal tripping caused by manual operation.

Fig. 2 is a schematic flow chart of an automatic control method of a vapor compressor according to the present application, where the method is applied to a work control module of an automatic control system of a vapor compressor as described above, and as shown in fig. 2, the method includes:

in step 201, in response to a user's evaporation task execution instruction, a desired inlet pressure and a desired outlet pressure of the vapor compressor are determined, and the vapor compressor is controlled to enter a start-up preparation state.

In particular, it will be appreciated based on the foregoing that for a vapor compressor, the inlet pressure and outlet pressure will directly determine the performance of the vapor compressor, and that after a user issues an evaporation task, the desired inlet pressure and desired outlet pressure (i.e., the inlet pressure and outlet pressure that best match the evaporation task) of the vapor compressor will need to be determined. Based on this, smooth and efficient execution of the evaporation task can be ensured. More specifically, fig. 3 is a schematic flow chart of determining a desired inlet pressure and a desired outlet pressure of the vapor compressor according to the present application, and as shown in fig. 3, the determining the desired inlet pressure and the desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user specifically includes:

step 2011, responding to an evaporation task execution instruction of a user, and acquiring job indication information in the evaporation task execution instruction; the operation indication information comprises names of materials to be evaporated;

Step 2012, determining an evaporation temperature and a preheating temperature of the material to be evaporated based on the name of the material to be evaporated, determining evaporation rate ranges corresponding to different material flow rates based on the preheating temperature and the evaporation temperature of the material to be evaporated and design parameters of evaporators in the current evaporation system, and determining an inlet temperature range and an inlet pressure range of the vapor compressor corresponding to the evaporation rate ranges based on the temperature and the pressure loss model of the current evaporation system;

It can be understood that the evaporation task execution instruction includes operation indication information, where the operation indication information includes a name of a material to be evaporated, and based on this, the embodiment of the present application can quickly determine thermodynamic characteristics of the material to be evaporated, so as to quickly and accurately determine a combination of an evaporation temperature (i.e., a boiling point temperature, at which the evaporation speed is the fastest) and a preheating temperature of the material to be evaporated. According to the embodiment of the application, the evaporation temperature and the preheating temperature of the material to be evaporated can be rapidly determined through the pre-established material information lookup table, and the material information lookup table comprises the mapping relation between the boiling point temperatures and the preheating temperatures of different materials to be evaporated, which are set based on the existing material property data and the experience knowledge.

After the evaporation temperature and the preheating temperature of the material to be evaporated are determined, the evaporation rate range corresponding to different material flow rates can be rapidly determined based on the preheating temperature and the evaporation temperature of the material to be evaporated and the design parameters of the evaporator in the current evaporation system. Specifically, the design parameters of the evaporator include a heat transfer area and a heat transfer coefficient of the evaporator, and correspondingly, the determining the evaporation rate range corresponding to different material flow rates based on the preheating temperature and the evaporation temperature of the material to be evaporated and the design parameters of the evaporator in the current evaporation system specifically includes:

Determining heat transfer amounts corresponding to different material flow rates based on the preheating temperature, the evaporating temperature and the heat transfer area and the heat transfer coefficient of an evaporator in a current evaporating system of the material to be evaporated;

And determining the evaporation rate range corresponding to the different material flow rates based on the heat transfer quantity corresponding to the different material flow rates and the evaporation latent heat of the material to be evaporated.

It will be appreciated that for a given MVR system, the heat transfer area and heat transfer coefficient of the evaporator are known, and therefore, after the preheating temperature and evaporating temperature of the material to be evaporated are determined, the evaporation process can be simulated by a fluid mechanical (CFD) model, and the heat transfer amounts at different material flow rates can be calculated. On the basis, the evaporation rate range corresponding to different material flow rates can be determined based on the heat transfer quantity corresponding to the different material flow rates and the evaporation latent heat of the material to be evaporated. The evaporation latent heat refers to the heat absorbed by a substance in unit mass in the evaporation process, and the evaporation rate is the ratio of the heat transfer quantity to the evaporation latent heat of the material to be evaporated.

After the evaporation rate ranges corresponding to different material flow rates are determined, the embodiment of the application can determine the inlet temperature range and the inlet pressure range of the vapor compressor corresponding to the evaporation rate ranges based on the temperature and pressure loss model of the current evaporation system. According to the embodiment of the application, the inlet temperature and the inlet pressure conditions of the vapor compressor under different working conditions (different materials and different flow rates) of the current evaporation system can be determined through experiments in advance, and the temperature and pressure loss model is established based on experimental results. Based on the above, after determining the evaporation rate ranges corresponding to the material types and different material flow rates, the vapor compressor inlet temperature range and the inlet pressure range corresponding to the evaporation rate ranges can be quickly determined based on the temperature and pressure loss model of the current evaporation system.

Step 2013, determining the expected inlet pressure of the vapor compressor and the corresponding optimal material flow rate based on the comparison result of the vapor compressor inlet pressure range corresponding to the evaporation rate range and the designed inlet pressure of the vapor compressor;

It will be appreciated that for a given vapor compressor, a corresponding design inlet pressure will be set to ensure proper operation and efficiency of the compressor. However, for the application scenario of the embodiment of the present application, the desired inlet pressure of the vapor compressor may deviate from the design inlet pressure due to the different requirements of different evaporation tasks. In view of this problem, after determining the vapor compressor inlet temperature range and the inlet pressure range corresponding to the evaporation rate range, the embodiment of the present application further determines the desired inlet pressure and the corresponding optimal material flow rate of the vapor compressor based on the comparison of the vapor compressor inlet pressure range corresponding to the evaporation rate range and the design inlet pressure of the vapor compressor. Specifically, the determining the desired inlet pressure of the vapor compressor based on the comparison result of the vapor compressor inlet pressure range corresponding to the evaporation rate range and the design inlet pressure of the vapor compressor specifically includes:

When the design inlet pressure of the vapor compressor is in the vapor compressor inlet pressure range corresponding to the evaporation rate range, taking the design inlet pressure as the expected inlet pressure of the vapor compressor;

when the design inlet pressure of the vapor compressor is not in the vapor compressor inlet pressure range corresponding to the evaporation rate range, the target vapor compressor inlet pressure with the smallest difference from the design inlet pressure is taken as the expected inlet pressure of the vapor compressor.

Based on the method, the difference between the expected inlet pressure and the designed inlet pressure can be reduced to the greatest extent on the basis of matching the evaporation task requirement, so that the abnormal working condition of the steam compressor is avoided.

Step 2014, determining a desired outlet temperature of the vapor compressor based on the evaporation temperature of the material to be evaporated, and determining a desired outlet pressure of the vapor compressor based on the desired outlet temperature of the vapor compressor and a vapor compressor inlet temperature corresponding to the optimal material flow rate.

It will be appreciated that the desired outlet temperature of the vapor compressor may be set directly to the evaporation temperature of the material to be evaporated in general. On the basis, the expected temperature rise of the vapor compressor can be determined based on the expected outlet temperature of the vapor compressor and the inlet temperature of the vapor compressor corresponding to the optimal material flow rate, the expected compression ratio (the compression ratio is the ratio of the outlet pressure to the inlet pressure) of the vapor compressor is determined based on the corresponding relation between the predetermined temperature rise of the vapor compressor and the compression ratio, and the expected outlet pressure of the vapor compressor is determined based on the expected inlet pressure and the expected compression ratio.

Based on the means, the automatic control method of the vapor compressor can enable the set MVR system to be matched with different evaporation task demands, and determine the optimal working state of the vapor compressor. After determining the desired inlet pressure and the desired outlet pressure of the vapor compressor, the vapor compressor may be controlled to enter a start-up preparation state.

The control of the vapor compressor into a start-up preparation state specifically comprises:

monitoring and adjusting state information of a target part of the steam compressor based on preset starting conditions of the steam compressor; wherein, the starting condition of the steam compressor is as follows: the oil temperature and the oil pressure of the lean oil station are not lower than preset thresholds; the opening and closing states of the air compensating valve and the anti-surge valve are that the air compensating valve is closed and the anti-surge valve is opened; the working state of the motor temperature control system is that the cooling system works, the heating system is closed, and the frequency converter is ready.

It should be noted that, whether the vapor compressor is in a standby state or in a shutdown state before entering the start-up preparation state, the state information of the target components of the vapor compressor needs to be monitored and adjusted based on the preset start-up condition of the vapor compressor after entering the start-up preparation state, so that the vapor compressor meets the start-up condition, and faults such as failure in starting the vapor compressor or surge are avoided. It can be appreciated that if the oil temperature and the oil pressure of the lean oil station are lower than the preset threshold, performing targeted adjustment until the oil temperature and the oil pressure of the lean oil station are not lower than the preset threshold; if the open and close states of the air compensating valve and the anti-surge valve are not the air compensating valve closing state and the anti-surge valve opening state, the adjustment is carried out until the air compensating valve is closed and the anti-surge valve opening state; if the working state of the motor temperature control system is not that of the cooling system, the heating system is closed, and the motor temperature control system is adjusted until the cooling system works, and the heating system is closed; if the frequency converter is not ready, the frequency converter is adjusted until the frequency converter is ready.

Step 202, starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor.

Specifically, the production start-up conditions include a vapor compressor start-up condition and an associated plant status condition, the associated plant status condition including: the evaporator starts feeding; correspondingly, the main motor frequency of the vapor compressor is controlled based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor, and the main motor frequency comprises the following specific components:

determining a current demand compression ratio based on a real-time inlet pressure and a real-time inlet temperature of the vapor compressor;

A demand frequency of the main motor is determined based on the current demand compression ratio, and the frequency of the main motor is adjusted to the demand frequency.

It will be appreciated that in order to avoid energy waste caused by the long-term operation of the vapor compressor in an idle state, embodiments of the present application only start the main motor of the vapor compressor if it is determined that both the vapor compressor start-up condition and the associated equipment state condition (i.e., the evaporator is beginning to feed) are met. Further, since the evaporator does not generate enough steam when the evaporator starts feeding, there is also not enough secondary steam (i.e. the steam compressed by the vapor compressor) to heat the material to be evaporated, and thus external steam needs to be introduced to heat the material to be evaporated, and at this time, the inlet pressure and the inlet temperature of the vapor compressor are not expected. In view of this problem, embodiments of the present application control the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor, specifically, first determine the current demand compression ratio based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor, then determine the demand frequency of the main motor based on the current demand compression ratio, and adjust the frequency of the main motor to the demand frequency. More specifically, the required temperature rise is first determined based on the real-time inlet temperature and the desired outlet temperature, and then the required compression ratio is determined based on the correspondence between the temperature rise and the compression ratio. After the required compression ratio is determined, the required frequency can be determined based on the corresponding relation between the compression ratio and the frequency of the main motor, and then the frequency of the main motor is adjusted to be the required frequency. Based on this, the evaporation rate of the material to be evaporated can be increased as much as possible, thereby bringing the vapor compressor into production (i.e. to the desired inlet pressure and the desired outlet pressure) at the fastest speed.

Step 203, determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information includes a basic state parameter and a compression state parameter.

Based on the foregoing, it can be understood that as the evaporation rate of the material to be evaporated increases, the vapor compressor will gradually enter the production state (i.e. reach the desired inlet pressure and the desired outlet pressure), and since the compression ratio of the vapor compressor has a corresponding relationship with the main motor frequency, the embodiment of the application can directly determine whether the vapor compressor enters the production state based on the real-time main motor frequency of the vapor compressor, and perform abnormal condition monitoring and processing based on the target state information of the vapor compressor after the vapor compressor enters the production state. Specifically, the target state information includes a basic state parameter and a compression state parameter. The basic state parameters include: the temperature of the motor bearing, the temperature of the motor stator winding, the oil supply temperature and pressure of the thin oil station, the temperature of the speed increasing box bearing and the vibration amplitude of the speed increasing box bearing; the compression state parameters include: vapor compressor inlet pressure and vapor compressor outlet pressure;

The abnormal working conditions comprise basic state abnormality and compression state abnormality; correspondingly, the method for monitoring and processing the abnormal working condition based on the target state information of the steam compressor specifically comprises the following steps:

monitoring and processing basic state anomalies based on basic state parameters of the vapor compressor; meanwhile, compression state abnormality monitoring and processing are performed based on compression state parameters of the vapor compressor.

It can be understood that, for basic state anomalies such as motor bearing temperature, motor stator winding temperature, thin oil station oil supply temperature and pressure, speed increasing box bearing temperature and speed increasing box bearing vibration amplitude, can judge based on corresponding preset threshold value, under normal circumstances, speed increasing box bearing can carry out periodic maintenance, and the probability of occurrence of bearing vibration amplitude anomaly is extremely low. The motor bearing temperature, the motor stator winding temperature, the oil supply temperature and pressure of the thin oil station and the speed increasing box bearing temperature are high in abnormal probability, and when abnormal conditions are monitored, the abnormal conditions can be processed through corresponding cooling or depressurization equipment, so that normal production cannot be influenced. However, when the compression state is abnormal, the damage to the vapor compressor and the production interruption can be caused, so that the monitoring and treatment of the abnormal compression state are focused on in the embodiment of the application. Specifically, fig. 4 is a schematic diagram of a process flow for monitoring and handling abnormal compression state provided by the present application, and as shown in fig. 4, the process for monitoring and handling abnormal compression state based on the compression state parameters of the vapor compressor specifically includes:

Step S1, determining whether the inlet pressure of the vapor compressor is abnormal or not based on the ratio of the inlet pressure of the vapor compressor to the expected inlet pressure (the inlet pressure abnormality may be caused by an external factor or a system fault), if so, executing step S2, otherwise, jumping to execute step S3;

Step S2, adjusting the opening of the air compensating valve until the inlet pressure of the compressor is recovered to be normal (the opening of the air compensating valve is adjusted to increase or decrease the air compensating amount so as to adjust the inlet pressure of the vapor compressor to be recovered to a normal value, so that the normal operation and performance of the vapor compressor can be ensured), and executing step S3;

Step S3, based on the comparison result of the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor and the expected value, determining whether the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is abnormal (the abnormal outlet pressure may be caused by internal faults of the vapor compressor or system problems), if so, executing step S4, otherwise, jumping to execute step S5;

Step S4, adjusting the anti-surge valve to a first opening degree until the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is recovered to be normal (the outlet pressure of the vapor compressor is regulated to be recovered to a normal value by adjusting the opening degree of the anti-surge valve to increase or decrease the leakage flow rate;

Step S5, determining whether the operation current of the steam compressor fluctuates or not based on the sampling value of the operation current of the steam compressor at preset time intervals, if so, adjusting the anti-surge valve to a second opening degree until the operation current of the steam compressor does not fluctuate, executing step S6, otherwise, directly executing step S6; wherein the second opening is larger than the first opening (current fluctuation is extremely liable to cause surge, so the second opening is set to be larger than the first opening to provide a larger adjustment range and avoid surge at the fastest speed);

step S6, the anti-surge valve is closed, and the step S1 is performed in a jumping manner (thus, the stable operation of the vapor compressor and the normal adjustment of the compression state can be maintained).

The method is used for monitoring and adjusting in real time by comparing the pressure parameter and the current fluctuation condition of the compressor so as to ensure the normal operation and performance of the vapor compressor. The system can timely find and process the abnormal condition of the compression state, improve the reliability and stability of the system, and reduce the energy consumption and loss.

More specifically, determining that the vapor compressor inlet pressure is abnormal in the event that the ratio of the vapor compressor inlet pressure to the desired inlet pressure is below a first preset percentage for a first preset duration;

determining that the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is abnormal if the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is greater than a second preset percentage of the desired value;

And determining the fluctuation of the operation current of the steam compressor under the working condition that the difference value of the operation current sampling values of the adjacent steam compressors exceeds a preset fluctuation threshold value and lasts for a second preset duration.

Wherein the first preset percentage is preferably 75%, the desired value is a ratio of a desired outlet pressure to a desired inlet pressure of the vapor compressor, and the second preset percentage is obtained based on the following calculation formula:

Wherein f is the actual running frequency of the main motor, k is the surge coefficient, and when the expected value is not less than 2.1, the value of k is 1.06-1.07; when the expected value is not more than 1.95, the k takes the value of 1.08-1.1; when the expected value is more than 1.95 and less than 2.1, k takes the value of 1.07-1.08. Because the vapor compressor will quickly enter a surge condition when the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is abnormal, the abnormal ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure can be accurately captured and quickly responded based on the above formula.

Further, the preset time interval, the preset fluctuation threshold, the first opening and the second opening may be set according to actual situations, which is not specifically limited in the embodiment of the present application. Meanwhile, it is considered that the variation of the inlet pressure and the operation current of the vapor compressor does not immediately induce surge, and the variation of the inlet pressure and the operation current may be caused by other disturbances, and the fluctuation is not sustained when the fluctuation is caused by the other disturbances. Based on the above, in order to avoid erroneous judgment of abnormal working conditions to the maximum extent on the basis of ensuring process safety, the embodiment of the application adds a time length judgment condition (namely, a first preset time length and a second preset time length) to the judgment conditions of abnormal inlet pressure and abnormal running current respectively. The first preset time period is preferably 3-5 seconds, and the second preset time period is preferably 1-3 seconds.

And step 204, controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

Specifically, whether the current evaporation is finished or not can be judged based on the material level in the evaporator. It can be understood that if it is judged that the evaporation task is finished in the process of monitoring the abnormal compression state based on the compression state parameter of the vapor compressor, the monitoring is stopped and the vapor compressor is controlled to enter the standby state. The specific implementation of the standby state is described in detail in the foregoing, and will not be repeated here.

The method provided by the embodiment of the application comprises the following steps: determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state; starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor; determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters; under the condition that the current evaporation task is finished, the vapor compressor is controlled to enter a standby state, full-automatic control of the vapor compressor in a given MVR system can be realized, and adaptation of different evaporation tasks is realized while faults such as abnormal tripping caused by manual operation are avoided.

The following describes the automatic control device of the vapor compressor provided by the application, and the control device of the automatic control system of the vapor compressor and the control method of the automatic control system of the vapor compressor described below can be correspondingly referred to each other.

Based on any of the above embodiments, fig. 5 is a schematic structural diagram of an automatic control device for a vapor compressor according to the present application, as shown in fig. 5, the device includes:

A first control unit 301 for determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state;

a second control unit 302 for starting the main motor of the vapor compressor in case that the production start condition is judged to be satisfied, and controlling the main motor frequency of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor;

A first processing unit 303, configured to determine whether the vapor compressor enters a production state based on a real-time main motor frequency of the vapor compressor, and perform abnormal condition monitoring and processing based on target state information of the vapor compressor after the vapor compressor enters the production state; the target state information comprises basic state parameters and compression state parameters;

And a third control unit 304, configured to control the vapor compressor to enter a standby state when the current evaporation task is finished.

According to the device provided by the embodiment of the application, the first control unit 301 responds to the evaporation task execution instruction of the user to determine the expected inlet pressure and the expected outlet pressure of the vapor compressor and control the vapor compressor to enter a starting preparation state; the second control unit 302 starts the main motor of the vapor compressor in the case that the production start condition is judged to be satisfied, and controls the main motor frequency of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor; the first processing unit 303 determines whether the vapor compressor enters a production state based on the real-time main motor frequency of the vapor compressor, and monitors and processes abnormal working conditions based on target state information of the vapor compressor after the vapor compressor enters the production state; the target state information comprises basic state parameters and compression state parameters; the third control unit 304 controls the vapor compressor to enter a standby state when the current evaporation task is finished, so that full-automatic control of the vapor compressor in the given MVR system can be realized, and adaptation of different evaporation tasks can be realized while faults such as abnormal tripping caused by manual operation are avoided.

Fig. 6 illustrates a physical schematic diagram of an electronic device, as shown in fig. 6, which may include: processor 401, communication interface (Communications Interface) 402, memory 403 and communication bus 404, wherein processor 401, communication interface 402 and memory 403 complete communication with each other through communication bus 404. The processor 401 may call logic instructions in the memory 403 to perform the automatic control method of the vapor compressor provided by the above methods, the method comprising: determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state; starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor; determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters; and controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

Further, the logic instructions in the memory 403 may be implemented in the form of software functional units and stored in a computer readable storage medium when sold or used as a stand alone product. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

In another aspect, the present application also provides a computer program product comprising a computer program, the computer program being storable on a non-transitory computer readable storage medium, the computer program, when executed by a processor, being capable of executing the method for automatically controlling a vapor compressor provided by the above methods, the method comprising: determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state; starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor; determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters; and controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

In yet another aspect, the present application also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, is implemented to perform the method for automatically controlling a vapor compressor provided by the above methods, the method comprising: determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state; starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor; determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters; and controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. An automatic control system for a vapor compressor, the system comprising:

The state monitoring module is used for acquiring state information of the steam compressor;

The work control module is used for determining the expected working state of the vapor compressor based on the evaporation task execution instruction of the user, and controlling the vapor compressor to start to execute the evaporation task until the evaporation task is completed based on the expected working state of the vapor compressor and the state information of the vapor compressor so as to control the vapor compressor to enter the standby state.

2. A method for automatically controlling a vapor compressor, the method being applied to an operation control module of an automatic control system of a vapor compressor according to claim 1, the method comprising:

Determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, and controlling the vapor compressor to enter a start-up preparation state;

starting a main motor of the vapor compressor under the condition that the production starting condition is judged to be met, and controlling the frequency of the main motor of the vapor compressor based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor;

Determining whether the steam compressor enters a production state based on the real-time main motor frequency of the steam compressor, and monitoring and processing abnormal working conditions based on target state information of the steam compressor after the steam compressor enters the production state; the target state information comprises basic state parameters and compression state parameters;

And controlling the vapor compressor to enter a standby state under the condition that the current evaporation task is ended.

3. The automatic control method of a vapor compressor according to claim 2, wherein said determining a desired inlet pressure and a desired outlet pressure of the vapor compressor in response to an evaporation task execution instruction of a user, specifically comprises:

Responding to an evaporation task execution instruction of a user, and acquiring job indication information in the evaporation task execution instruction; the operation indication information comprises names of materials to be evaporated;

Determining the evaporation temperature and the preheating temperature of the material to be evaporated based on the name of the material to be evaporated, determining the evaporation rate range corresponding to different material flow rates based on the preheating temperature and the evaporation temperature of the material to be evaporated and the design parameters of an evaporator in a current evaporation system, and determining the inlet temperature range and the inlet pressure range of a vapor compressor corresponding to the evaporation rate range based on the temperature and the pressure loss model of the current evaporation system;

Determining a desired inlet pressure of the vapor compressor and a corresponding optimal material flow rate based on a comparison of the vapor compressor inlet pressure range corresponding to the evaporation rate range and a design inlet pressure of the vapor compressor;

The desired outlet temperature of the vapor compressor is determined based on the evaporation temperature of the material to be evaporated, and the desired outlet pressure of the vapor compressor is determined based on the desired outlet temperature of the vapor compressor and the vapor compressor inlet temperature corresponding to the optimal material flow rate.

4. The automatic control method of a vapor compressor according to claim 3, wherein the design parameters of the evaporator include a heat transfer area and a heat transfer coefficient of the evaporator, and the determining the evaporation rate range corresponding to different material flow rates based on the preheating temperature, the evaporation temperature, and the design parameters of the evaporator in the current evaporation system specifically includes:

Determining heat transfer amounts corresponding to different material flow rates based on the preheating temperature, the evaporating temperature and the heat transfer area and the heat transfer coefficient of an evaporator in a current evaporating system of the material to be evaporated;

And determining the evaporation rate range corresponding to the different material flow rates based on the heat transfer quantity corresponding to the different material flow rates and the evaporation latent heat of the material to be evaporated.

5. The method of automatic control of a vapor compressor according to claim 4, wherein said determining a desired inlet pressure of the vapor compressor based on a comparison of a vapor compressor inlet pressure range corresponding to said evaporation rate range and a design inlet pressure of the vapor compressor, specifically comprises:

When the design inlet pressure of the vapor compressor is in the vapor compressor inlet pressure range corresponding to the evaporation rate range, taking the design inlet pressure as the expected inlet pressure of the vapor compressor;

when the design inlet pressure of the vapor compressor is not in the vapor compressor inlet pressure range corresponding to the evaporation rate range, the target vapor compressor inlet pressure with the smallest difference from the design inlet pressure is taken as the expected inlet pressure of the vapor compressor.

6. The method for automatically controlling a vapor compressor according to claim 5, wherein said controlling the vapor compressor to enter a start-up preparation state comprises:

monitoring and adjusting state information of a target part of the steam compressor based on preset starting conditions of the steam compressor; wherein, the starting condition of the steam compressor is as follows: the oil temperature and the oil pressure of the lean oil station are not lower than preset thresholds; the opening and closing states of the air compensating valve and the anti-surge valve are that the air compensating valve is closed and the anti-surge valve is opened; the working state of the motor temperature control system is that the cooling system works, the heating system is closed, and the frequency converter is ready.

7. The automatic control method of a vapor compressor of claim 6, wherein the production start-up conditions include a vapor compressor start-up condition and an associated equipment status condition, the associated equipment status condition comprising: the evaporator starts feeding; correspondingly, the main motor frequency of the vapor compressor is controlled based on the real-time inlet pressure and the real-time inlet temperature of the vapor compressor, and the main motor frequency comprises the following specific components:

determining a current demand compression ratio based on a real-time inlet pressure and a real-time inlet temperature of the vapor compressor;

A demand frequency of the main motor is determined based on the current demand compression ratio, and the frequency of the main motor is adjusted to the demand frequency.

8. The automatic control method of a vapor compressor according to claim 7, wherein the basic state parameters include: the temperature of the motor bearing, the temperature of the motor stator winding, the oil supply temperature and pressure of the thin oil station, the temperature of the speed increasing box bearing and the vibration amplitude of the speed increasing box bearing; the compression state parameters include: vapor compressor inlet pressure and vapor compressor outlet pressure;

The abnormal working conditions comprise basic state abnormality and compression state abnormality; correspondingly, the method for monitoring and processing the abnormal working condition based on the target state information of the steam compressor specifically comprises the following steps:

monitoring and processing basic state anomalies based on basic state parameters of the vapor compressor; meanwhile, compression state abnormality monitoring and processing are performed based on compression state parameters of the vapor compressor.

9. The automatic control method of a vapor compressor according to claim 8, wherein the compression state abnormality monitoring and processing based on the compression state parameter of the vapor compressor specifically comprises:

Step S1, determining whether the inlet pressure of the vapor compressor is abnormal or not based on the ratio of the inlet pressure of the vapor compressor to the expected inlet pressure, if so, executing step S2, otherwise, jumping to execute step S3;

step S2, adjusting the opening of the air compensating valve until the inlet pressure of the compressor returns to normal, and executing step S3;

step S3, based on the comparison result of the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor and the expected value, determining whether the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is abnormal, if yes, executing step S4, otherwise, jumping to execute step S5;

step S4, adjusting the anti-surge valve to a first opening degree until the ratio of the outlet pressure of the vapor compressor to the inlet pressure of the vapor compressor is recovered to be normal, and executing step S5;

step S5, determining whether the operation current of the steam compressor fluctuates or not based on the sampling value of the operation current of the steam compressor at preset time intervals, if so, adjusting the anti-surge valve to a second opening degree until the operation current of the steam compressor does not fluctuate, executing step S6, otherwise, directly executing step S6; wherein the second opening is larger than the first opening;

and S6, closing the anti-asthma valve, and jumping to execute the step S1.

10. The automatic control method of a vapor compressor according to claim 9, wherein the vapor compressor inlet pressure abnormality is determined in the case where a ratio of the vapor compressor inlet pressure to the desired inlet pressure is lower than a first preset percentage for a first preset period of time;

determining that the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is abnormal if the ratio of the vapor compressor outlet pressure to the vapor compressor inlet pressure is greater than a second preset percentage of the desired value;

And determining the fluctuation of the operation current of the steam compressor under the working condition that the difference value of the operation current sampling values of the adjacent steam compressors exceeds a preset fluctuation threshold value and lasts for a second preset duration.