Research And Design Of Multifunctional Data Acquisition System Based On DSP And CPLD

Hydropower is a clean and renewable energy,the hydropower industry is developing rapidly in China,and the installed capacity of hydropower units is increasing.To ensure the safe and stable operation of the hydroelectric generating units,a real-time monitoring of the operation status is essential.So the hidden problems can be detected in time,and then appropriate measures will be taken to prevent accidents.It also instructs the condition-based maintenance.Data acquisition is a very important part of the condition monitoring,and it is the basic task of data acquisition system to acquire the state parameters of hydropower units accurately.As one of the key control equipment of hydropower units,the health statuses of hydraulic turbine governing system are directly related to the safe and stable operation of hydropower units.So the main research object of this paper is the hydraulic turbine governing system.With comparison of various data acquisition schemes,and in consideration of the characteristics of signals to be monitored,a multifunctional data acquisition system is designed.It mainly consists of DSP chip TMS320F2812,CPLD chip EPM7128 S,and Ethernet chip W5100 which is used to realize communication with remote server.With the study of Nyquist Sampling Theorem and anti aliasing filter,a high performance ADC chip is adopted,and it is helpful to simplify the circuit design.The data acquisition system also have analog output function,through the DAC chip and the voltage/current output driver chip combination design,the system can output voltage signals and current signals.In addition,the data acquisition system can measure the frequency of signals,and output square wave signals with adjustable frequency.It also can measure switch signals,and meanwhile output switch signals.All in all,the data acquisition system is functionally complete,it can measure a variety of signals in hydraulic turbine governing system.The data acquisition system also makes full use of existing analog measurement module.It samples three-phase voltage and current signals,and then obtains active power through DSP programming in which IIR digital filter and other algorithms are used.It is compatible with different connection mode of three-phase three-wire and three-phase four-wire system.In view of the large number of signals that need to be measured in the condition monitoring system,the SPI extension interface is reserved.So an additional data acquisition module can be connected with the data acquisition through SPI communication interface.By employing CPLD in the design,the weakness of DSP logic control ability and the lack of I/O interface are improved.The application of CPLD makes the system more flexible.The data acquisition system has the advantages of high sampling precision,fast transmission speed,convenient operation,complete functions,easy expansion and portability,so it can be widely used in the condition based maintenance of hydraulic turbine governing system.