Jet cooling system solution based on ICP DAS WinPAC

1. Application Background

"Jet technology" refers to various jet devices and process systems mainly composed of jet pumps, ejectors, and nozzles. They include devices and process flows such as the transportation and compression of fluids (liquids, gases, and bulk solids), jet vacuum, jet refrigeration, jet deoxidation, jet propulsion, jet mixing and reaction, jet combustion, sprinkler irrigation, spraying, spraying, jet aeration, jet cutting, and jet control. "Jet technology" is a new high-tech discipline involving energy transfer, mass transfer, and chemical reactions of multiphase fluids such as liquids, gases, and solids. At present, it has been widely used in various sectors of my country's national economy and has gradually formed an emerging industry. In particular, in the cooling system of water turbine generator sets, there is a strong demand for intelligent hydraulic jet devices.

2. Application Requirements

The basic structure diagram of the intelligent cooling device for hydro-generators is as follows (Figure 1). The electrical automation system of the device is one of the core components of the entire system. It is used for key data acquisition and implementation of control strategies and is the key to the intelligence of the entire device. The biggest challenge of the system is the need to realize the self-learning function of the system, that is, the entire device requires the automation system to automatically adjust the control strategy according to the characteristics of the environment and find the best control strategy. This requires that the automation system must have intelligent modeling capabilities based on fuzzy algorithms in addition to traditional data acquisition and control.

In addition to realizing the self-learning function of the system, the automation system also has three major challenges:

1. Realize control redundancy of the main controller and establish a dual-controller redundant system to ensure uninterrupted operation of the system;

2. Integrate stepper motor drive into traditional I/O control system to achieve efficient motor control function;

3. The control system works in a high temperature and high humidity environment, and each component needs to have good environmental adaptability.

3.ICPDAS Solutions

1. Hardware Solution

The control platform uses ICP DAS W-8331 WinPAC controller, which can handle more complex tasks and realize main control unit and I/O redundancy. Its features are as follows:

ü Provide 32-bit CPU, 64M SDRAM and 1G CF card to handle complex business

ü Adopt Windows CE.net operating system, providing multi-threaded processing capabilities

ü Support eVC++ programming to help users realize complex fuzzy control program design

ü Provide multiple communication methods to meet users' needs for redundant functions

ü Stronger wide temperature working capability to meet efficient working conditions in various working conditions

ü Built-in RTC and dual watchdogs ensure system stability

In the system, W-8331 is matched with I-87017RC and I-87057 to realize the functions of analog quantity acquisition and switch quantity output.

2. Integrated Solutions

The basic control system architecture of the intelligent water turbine generator set jet cooling system is shown in Figure 2. The system integrates analog signal processing, digital signal processing, and stepper electrical control into one control system, greatly simplifying the work required for system design and system implementation. ICP DAS also provides users with a wealth of development functions, allowing traditional IT developers to quickly master the characteristics of automation system development, and allowing developers to focus on application development without having to consider the hardware implementation process too much. It is this effective combination that has enabled developers to develop innovative control systems based on ICP DAS PAC products in a short period of time, realizing the intelligent modeling function based on fuzzy control that is rare in the traditional automation industry, winning a reputation for system developers and gaining high praise from users.

3. Low-cost redundant control solution

The cooling of the turbine generator set is an uninterrupted task, which requires the jet cooling system to maintain a continuous working state. To achieve this requirement, the developers used two W-8331 controllers for dual-machine redundant configuration to ensure the continuous and reliable operation of the jet cooling system. The system redundant control architecture is shown in Figure 3:

1. Two W-8331 controllers are equipped with the same I/O modules and the same stepper motor drive system. Both W-8331 controllers are connected to the monitoring server through the network, one as the main controller and the other as the backup controller;

2. Two W-8331 controllers are connected through RS-485 interface. The main controller writes the real-time operation status and various parameters into the internal database of the standby W-8331 controller through RS-485 port;

3. When the main controller fails or needs maintenance, the standby controller can automatically enter the working state and record the real-time status data and parameters. When the main controller resumes working, the standby controller will first refresh the data and parameters on the main controller, and then start the main controller to enter the working state.

4. Benefits of the system

Due to the openness and ease of use of the ICP DAS PAC system, a computer professional completed the system development in just 4 weeks, and completed the design of a redundant system by using two W-8331 controllers without adding other control devices, which greatly improved the stability and reliability of the system. More importantly, the user only spent less than half of the hardware investment of traditional solutions. Currently, the system is running stably in foreign hydropower stations, providing cooling services for hydro-turbine generators.