“LabVIEW has made it easier for us to visualize data and manage controls related to power generation, also having advanced visualization controls.”
The challenge:
Develop a control and monitoring system for a power generation system through the electrochemical reaction between Hydrogen and Oxygen.
This system must allow more than one work mode, handling different controls for each mode, and storing the most relevant values in terms of energy generation.
The solution:
Use of LabVIEW to monitor the data and manage the controls of each generator.
In addition, due to the ease with which LabVIEW manages the files, standard functions are used to store the obtained values.
Introduction
Today, it is increasingly common to see how companies invest in the search for new sources of energy generation to save costs and reduce the level of pollutants. One of the most popular alternatives on the market is the electrochemical reaction based on hydrogen, since it is easily transportable, storable, clean and inexhaustible. Hydrogen is an element that is found throughout the planet. However, it has to be extracted from natural sources, since it is not a primary source. Obtaining energy from said element offers several advantages: it does not contaminate or consume natural resources, its operation is silent, it requires little maintenance and it has a long useful life.
In order to get the most out of this technology, many companies are investing in finding the most profitable solutions.
In this context, CEGASA, in collaboration with ULMA Embedded Solutions, has developed a power generation system through the electrochemical reaction of hydrogen and oxygen. Said system is in charge of controlling the transformation process of the mixture of hydrogen and air under tension. The design is capable of generating a maximum power between 1 and 1,5 kW in a modular way combining up to 5 individual generators. Each generator is connected to a CAN bus and is commanded by a central control system (GCS) in master/slave mode.
Control and data acquisition
As can be seen in the image below, the application (PcApp_STH2C) is based on LabVIEW technology and incorporates a CANopen communications library through which data is exchanged between the application itself, the GCS subsystem and a maximum of 5 generators (GE1V2). The application is compiled for three different types of profiles: administrator, user, and monitor. Each profile will offer different levels of control to the end user.
The system called STH2C consists of a string of 5 generators (GE1V2) and converters, as shown in the figure. It is accompanied by an external UPS necessary for startup.
The GCS is the control element that regulates the operation of the set of controllers.
The control system manages the generation of electrical energy from hydrogen according to the indications received by an operator or an external management system. In the same way, it allows visualizing the performance of the system as well as acting on the outputs manually.
The operator can also configure the parameters of the system to adjust it to the needs of a specific application.
For the correct persistence of the data shared by all the elements that take part in the generation (generator, GCS and control application), an object dictionary (DO) has been designed in which all the variables to be exchanged between the GCS and all generators.
This DO must also be implemented in LabVIEW for the PC application, since the application will be fed with the data offered by the CAN communications interface for the visualization and control of the generators. Cluster-type variables have been used for each structure of the DO, maintaining a memory map as closely adjusted to that of the GCS. (see figure 1)
The application is made up of a series of screens whose navigation depends on the different user profiles and the availability of the generators themselves and/or GCS. If no element is identified on the CAN bus, there is no navigation possibility.
Once inside the application, the data acquired through the CAN communications interface will be displayed in LabVIEW display elements such as tables, graphs, images, leds... (see figure 2).
As the states of the generators and the GCS change, these states will be reflected in the different display elements that have been used, and control elements such as buttons, slides... will be enabled accordingly.
Parallel to the control of the generators, the possibility of storing the data of each and every one of the generators is offered.
The generated power, current, voltage, and temperature are displayed on the screen using LabVIEW graphical controls. The data obtained is also stored on the PC disk at a frequency set by the user. (see figure 3)
alarm management
To warn of a possible malfunction of the generation string, some alarms have been defined so that the end user can have a complete report of the generation process. These alarms use LabVIEW visual elements. (see figure 4)
Both in the statistics and in the alarms, the events that have been registered in the generators themselves and/or GCS can be read, and they can be stored in tabulated text format, prepared for reading using Microsoft Excel.
The main statistics are those related to the number of starts, the total hours of execution and the total energy per hour distributed by the string.
Both the statistics and the alarms can be deleted from memory as long as we are in manual mode. All the events detected so far will be cleaned, and everything that has happened from this moment will be stored again.
system usage
For each type of end customer that uses this system, a different application installation profile is provided, which has its respective restrictions in terms of execution.
Conclusion
LabVIEW has provided us with the visualization of the data and management of controls related to power generation, also having advanced visualization controls, such as graphics, LEDs, customizable buttons with different images...
Regarding the generation of installables according to different profiles, LabVIEW simplifies the creation of various levels of permissions using the initialization files.
