Development Of Measuring And Controlling System Of Single-phase Programmed AC Power Supply

In recent years, with the development of technology of power electronics and technology of automatic controlling, the performance of variable-frequency power source which is an important part of the power supply is directly related to the security and reliability of the system. In this paper, the measuring and controlling system of single-phase AC programmed power supply is a controlling and measuring system of a high-power frequency conversion power, and its output is the sine power signal that the frequency and amplitude can be adjusted and it can monitor and control the large power signal at the same time. The output of the system is a ideal signal and the amplitude(180V~300V) and the frequency(30Hz~1000Hz) of the signal can be adjusted freely responding to the user’s orders. The max output power is 40KW. In a sense, these characters can meet the demands of the user. So the user can get slight harmonic pollution supply and can get the right signal easily by changing the parameters through the man-machine mutual panel.In this paper, combining the theory of the electric machine control and using Direct Digital Frequency Synthesis (which is short for DDS or DDFS), we design a circuit that can generate modulated signal and carried signal. We chose the complex programmable logic(CPLD) device-EPM570T144I5 which is of high performance and low cost, and we design the logic circuit of DDS in it. The data of the modulated signal and carried signal is inputted into a high-speed static random access memory-61LV6416. Then, the data can convert to the analog signal through the DAC-AD5445. At last we can get the smooth signal through the low pass filter. In order to monitor and control the voltage, the current and other parameters of the system, we use the high-performance synchronous sample analog to digital converter(ADC) AD7656 to sample the signal from the mutual-inductor mutual. The output signal is regulated through the software PID. It can practice the stability output and ensure the high-sensibly.In this paper, the 32bit ARM7-LPC2214 processor of NXP company is used as the core of controlling and the high-speed CPLD EPM570T144I5 is used as the logic control unit, we can get a much better signal sample, analyse and processing, wave output and related controlling. In order to guarantee the performance of a real time of the arithmetic and controlling of the LPC2214, we use another ARM7 processor LPC2136 to process the key and LCD display specially.At last, through the practice and testing, we prove that the system satisfy the require of design with much better stability.