Design Of CPLD Dual Power Intelligent Transfer Switch System

With the development of social-economic and the improvement of the living quality, power supply has been more and more important. In order to ensure the continuity and stability of the power supply, many important occasions are equipped with double power. The double power can be switched effectively and accurately with the use of the automatic transfer switch. Now, the overall level of low-voltage electrical has been improved in the condition of the modern science and technology, and double power automatic transfer switch has occupied a very important position in low voltage electrical field, its comprehensive performance has improved continuously. So, double power transfer switch is widely used in various important load occasions.This article will take CPLD EMP1270as the core to accomplish the design of software and hardware. And the present widely-used AVR ATmega32micro-controller is applied to this design to communicate with CPLD to collect and process the double power supply signal related parameters. Through single chip CPLD device to realize the internal digital logic function of control system. In this way, it can reduce the use of discrete components, replacing the traditional design of the hardware circuit, to solve the problem of the high failure rate, low reliability and large volume. At the same time, it has the characteristics of high-speed parallel data processing. And has the advantage of high speed in controlling rather than micro-controller. Therefore, in the whole system design, using CPLD as the main control chip and AVR as auxiliary chips, by combining the two, it is possible to further improve the comprehensive performance of the system. This paper is mainly about the several parts listed below:First, according to the applications’ needs and expansibility of the power controller board, divide the functions into several parts to build the functional architecture, the main functional chips are chose and the peripheral circuit is designed, the schematic and PCB board are finished, the hardware platform is implemented.Second, complete the system design of digital logic functions by using Verilog HDL. Write the programs to realize the function of every circuit module. Verify whether the circuit design is reasonable or not by circuit simulation in Quartus Ⅱ9.0.Third, carries on the system software design. Use the ATmega32micro-controller to deal with the voltage and converts binary of frequency and temperature from CPLD into BCD code. Based on using PROFIBUS connection of RS-485, and write the communication protocols between the host and the slave. Then, accomplish to compile the program for micro-computer following the procedures for modular design, and realize remote telemeter, remote signaling, remote regulating, remote control and alarm/trouble shooting features. Keep voltage, current, temperature showing on PC and the controller panel, intuitive interface for image showing a real-time dynamic.Finally, through a lot of experiments, verify the operation of the system is correct operating modes. As certified by the test, when fault occurs, double power intelligent switch can quickly switch to another power supply, realizing the safe and reliable electricity, and can achieve full range current protection and remote control.