The automatic control system of diesel generator unit involves the computer control technology and related control theory of industrial machinery automation. In this paper, the situation and problems of diesel engine unit controller are briefly described, and then the matters needing attention in the application of MCU in diesel generator unit controller are analyzed, and the application value of intelligent controller of diesel generator unit based on MCU in industrial machinery automation is also discussed. As a common standby power generation equipment, diesel generating units have been widely used in various industrial fields.
At present, both the telecommunication system, the power system, the station and the computer room of the flood control and emergency department of water resources need uninterrupted power supply. However, the geographical location of these places is very different, some in the city center, some in the mountains. It is very difficult for the remote power supply room to be on duty all the time, which requires that these diesel generating units can be monitored and managed by computer, and that diesel generating units have efficient and good control system. At present, the controllers used in diesel generating units are mainly based on electronic governors, thermostatic element which are composed of external load distributors, parallel and disassembly controllers and voltage regulators. Therefore, it has become an inevitable trend and requirement for the development to improve the functions of the diesel generator unit controller, simplify the control system structure of the diesel generator unit and reduce the cost of the controller. By controlling the serial port of the generator set to communicate with the computer, the communication between the diesel engine set and the host computer is realized. The software program of the host computer is written by VC through the self-defined communication protocol on the computer, and the remote control of the generator set is implemented by the host computer. This can improve the level of work efficiency. It can also reduce the work intensity of the staff on duty and meet the actual needs. When the computer breaks down, it is necessary to realize the manual panel control of the generator set. When the controller of the generator set is in the manual state, the functions of the engine set can be realized by the function buttons on the control panel, such as the start-up, shutdown, switch-over of the generator set, etc. When the main batteries in the generator unit fail, they can be automatically converted to the standby batteries to start the generator unit. Sampling circuit: Firstly, the generator unit controller samples and analyses the voltage and frequency of the external network circuit to provide real and reliable data for the MCU controller.
SCM: As the core of the whole generator unit controller, SCM is composed of hardware and software. The chip used in the hardware part is 12 times higher than that of the ordinary single chip computer, and the macrocrystal ST89C52RC is famous for its high speed and low consumption. When the switch state changes, it reverses as a judgment condition. When the I0 port of MCU chip changes from high level to low level, according to the program already designed in MCU, the phase change of another group of I0 port can be controlled to drive the relay to turn on or off, so as to start the generator set and supply power to the equipment. The chip also has EEPR0M function, which can be compatible with 8951 instructions and update programs online. Flow Description: After the controller is started, the relevant data of the controller is acquired after the initialization of the serial port. On the interface of the computer remote control, the switch status of the external power, oil engine and ATS is displayed. When the controller detects the power supply problem of the external power grid, wait for 8 seconds; if the power supply of the external power grid is still abnormal, the program of the controller starts to open the custom generator function, first turn on the throttle of the generator, after one second start the generator, detect the voltage state of the generator, and if the voltage of the generator is normal, turn on the ATS. Turn off to the oil engine to generate electricity; if the voltage of the generator is abnormal, then choose to restart the generator, the whole process cycle three times. During this period, if the main batteries are abnormal, the ATS switch will automatically select the standby batteries to generate electricity. Similarly, the controller detects that the power supply of the external power grid begins to return to normal, and waits for 8 seconds, the power supply of the external power grid is still normal. The controller will convert the ATS switch to the municipal power supply, and the generator will start to shut down after 3 minutes of cooling. If abnormal phenomena occur in the cooling process of the generator in the external power grid, the controller will choose to change the ATS switch to the municipal power supply. Oil engine power supply. Output relay: Driven by MCU, the output relay sucks and disconnects according to the instructions of MCU to control the throttle, ATS switch and so on. PC: The controller in the generator set keeps communication with the computer through the serial port. The user-defined communication protocol is input into the programming of the single chip computer. The PC software is written by VC. The generator can be monitored remotely by the PC software. As shown in Fig. 2, the schematic diagram of the intelligent communication controller is shown. Under the action of the level conversion driving circuit, the I/O line and SIOO form a 9-pin RS232 serial port, which is connected with the modem. After confirming that the connection is correct, it is initialized. Similarly, under the action of TTL-RS485 level conversion drive circuit, SI01 forms RS485 serial port, which connects with all the devices located at the bottom by using double wiring. In addition, the controller has another function, that is, it is used to manage RS485 bus. The communication mode is mainly based on the communication protocol of the underlying equipment to establish information exchange. The on-chip RAM in MCU is used as the central memory of the system, and the controller is converted according to the system standard protocol, so that the information between the underlying equipment and the computer can be exchanged. The controller supports HDLC protocol. As shown in Table 1, the standard frame format is shown. The termination mark and the start mark are the same. They all occupy one byte. The address of the lower computer occupies the second byte. The control code occupies one byte after the address of the lower computer. The variable length data occupies M bytes. It is mainly composed of the state and data of each lower computer. Two kinds of checking methods are available. One is frame checking, which takes 2 bytes. The other is cyclic redundancy checking, which takes 4 bytes. The maximum data transmission rate of the controller is 33.6K baud, which supports many protocols and is easy to operate. In addition, the intelligent communication controller constructed in this paper can coordinate the management of the underlying equipment. For example, in the case of multi-unit interconnection, the controller has two identities, one is the power distributor, the other is the unit operation manager, which transmits power to each unit in a predetermined proportion. The software used in the development of man-machine interface program and communication program of this system is VC 6.0. The technology used in programming is Windows multithreading technology and Windows API technology. The control interface is displayed in the way of information query, as shown in Figure 3. Dialogue template is the basis of programming. API functions are packaged and processed.
AT instructions are used to complete dialing operation. At the same time, three threads are opened to wait for receiving events to generate signals. According to the content of signal commands, the underlying devices are read and operated. If the system runs normally, the timeout timer will be set during event 1 after three threads are opened; if the data reading operation is successful, continue to set event 2 and set the timeout timer accordingly; if event 2 is successful, return event 1 and update the data. Once the time-out occurs, the type and code of the current operating lower computer are recorded. When the time-out number reaches the set value, the alarm information is sent to the lower computer by the controller, and the operator is reminded by the form of status code. If the lower computer is confirmed to be in the shutdown state, the unit is no longer queried, and when the remote start-up occurs, the alarm information is sent to the lower computer. Query. The communication protocol of HDLC is used between the controller and the computer. When writing the program, the operation commands of the lower computer are limited. By contradictory commands, the purpose of locking each other is achieved. Thus, the operator can be effectively prevented from entering wrong operation commands. At the same time, the state of the operation buttons is observed, and the real-time state of the buffer commands and the commands of the lower computer can be known. When the alarm information is sent out by the system, the information will be printed automatically for the operator to watch. In addition, the operation interface can simultaneously grasp the power status, oil engine status, unit status, battery status, support manual control and automatic control. The practice proves that the accident rate caused by manual control is 15%, while the correct operation rate of intelligent control (automatic control) established in this paper is 6%.
It can be seen that the intelligent controller of diesel generator set constructed in this paper can find problems in time and take corresponding measures to reduce the accident occurrence. Rate. In addition, the application of intelligent controller can save manpower, reduce costs to a certain extent, and has great application value. At present, mobile pumping stations have been more and more widely used in flood control and rescue work in China. Mobile pumping stations have the characteristics of convenient operation and have become the main disaster relief weapons. The main components of mobile pumping station are diesel generator set, sewage pump, electrical control cabinet, rubber lining tape, refitted vehicle and other accessories such as lighting equipment. The performance of mobile pumping station mainly includes: full intelligent control; detection automation, program control process automation, data acquisition and display automation, which can automatically diagnose faults. At present, the controller chips of diesel engine pumps in China are fixed programming through single chip computer. They have complete functions and cover all the control programs of diesel engine pumps. They are used together with submersible pumps, mixed-flow pumps and centrifugal pumps for pumping and draining in flood control, rescue and disaster relief. No secondary programming is needed by professionals. They are simple, fast and safe. Reliable. The automatic control system of mobile power station based on MCU has the advantages of simple operation, clear structure, easy maintenance, reliable performance, etc. It has high use value, greatly improves the control system performance of mobile power station, and improves the work efficiency; the automatic updating and upgrading of its software system design The function can maintain the circuit in time, and further improve the security and efficiency of mobile power station. It effectively solves the problems of short use time and high wear degree of equipment, and greatly promotes the further development of industrial machinery automation in China.