With the development of electronic information technology and semiconductor technology, the application of embedded system is becoming more and more widespread. In the field of control, more and more high-performance microprocessors are used to meet the demands of more and more control applications. Based on ARM embedded platform digital voltage control system, to overcome the traditional knob or sliding type rheostat AC voltage analog control of the drawbacks. The system is based on embedded technology, in the embedded platform using ARM microprocessor real-time control of digital-analog signal conversion to control the sine wave voltage regulator module to adjust the size of the AC voltage. In this paper, the actual test of the system to verify the digital voltage control system of the functional characteristics, and quantitative testing of the system can be achieved AC voltage linear regulation of the conclusions. Digital voltage control system can be used as intelligent regulating device for voltage, home, medical and industrial automation and other fields, and has a high degree of regulation, good linearity adjustment, easy to operate and other characteristics. Voltage regulator control system as an intelligent regulator of the voltage management device commonly used in the family, medical and industrial automation and other fields. In the past, adjustment of AC voltage was usually realized by using slip or rotary rheostat connected to the voltage circuit. The long rotation of the knob could cause the adjustment insensitivity or even failure. The adjustment accuracy was reduced and the error was large. With the rapid development of electronic technology and embedded technology, more and more embedded systems are applied in control field. It is very important to realize digital voltage control system of digital intelligent control on embedded platform. In this paper, ARM Cotrex-A8 microprocessor is used to build the hardware control platform, and Linux is used as the embedded operating system, which is real-time and easy to develop.
The Design of ARM Digital Voltage Control System
ARM digital voltage control embedded system hardware design includes the overall design of the hardware, the processor selection and detailed hardware design. ARM digital voltage control system, the overall design phase of the main task is to follow the embedded system design process, a clear system needs to achieve the function of the hardware module division of the system hardware architecture framework to determine the selected processor model, set up the development environment has been Complete the system design goals.
1.1 ARM Digital Voltage Control System Structure
The overall hardware design of the system is based on the functional requirements of the system. The goal of this system is ARM digital voltage control system, the need to achieve through the digital signal control to complete the AC voltage intelligent regulation. A complete digital voltage control system includes the core control module, digital-analog signal conversion module, input and output modules and sine wave voltage regulator module composed of four parts. System block diagram shown in Figure 1. The user inputs the instruction from the input and output module to the control module. After receiving the instruction, the control module controls the digital-analog conversion module to execute the conversion of the digital signal to the analog signal. The conversion result is output to the sine wave voltage regulation module. Design and Realization of Digital Voltage Regulating Control System Based on ARM Core control module includes ARM processor, memory, NANDFlash, power management module, digital voltage control system of all control operations by the processor to complete. Processor with 512MB of DDR2 memory, SD card is used to store Linux system kernel image, file system, drivers and applications, the system after boot Bootloader will boot the operating system boot, and load the application to run in memory. Digital-analog signal conversion module mainly includes high-precision digital-analog conversion chip, use DAC7311 to achieve digital control signal to analog control signal conversion work, the conversion accuracy of up to 12 bits, through the serial synchronous interface with the processor connected. Input and output module as the user interface with the system, including an LCD touch screen, the user button, used to display system-related information, application program interface and control procedures for the operation. he sine wave voltage regulator module is connected with the digital-to-analog signal conversion module, and the analog control signal outputted after the digital-analog conversion is output to the sine wave voltage regulator module to realize the modulation of the AC voltage.
1.2 Microprocessor Selection
The main components of the core control module in this system is the embedded microprocessor. Embedded microprocessor selection in order to consider the performance of microprocessors, technical indicators, power consumption and the support of development tools. PCB design in the main consideration to the processor packaging and Layout design, layout, ease of wiring and the cost of plate and other issues. According to the system design goals and functional requirements, and integrated the design process of the relevant factors, this design chose Texas Instruments introduced ARM embedded microprocessors AM3354. AM3354 peripheral resource-rich, superior processing performance, and low power consumption, low cost. The AM3354 is available in two form-factor packages, 298-pin ZCE packages with 0.65 mm ball pitch, and 324-pin ZCZ packages with 0.80 mm pitch. According to PCB design principles in the design of 324 pins used ZCZ package chip.