Based On DSP Design And Implementation Of STATCOM In The Distribution Network

With the development of power electronics，a large number of non-linear loads haveappeared more and more many. It gradually increases, that the influencing factors of thesafe and stable operation to the power system. People pay on more and more attention tothe problems including the lack of reactive capacity, harmonic wave, therefore, it becomesmore important to the development and improvement of the reactive power compensationequipment.In this paper, the problem of power system reactive power compensation is analyzedand designed systematically, it introduces the research background and significance ofreactive compensation, the development of reactive power compensation device, and thecurrent situation of the development and advantages to the Static SynchronousCompensator(STATCOM). The working principle and characteristics and control mode ofSTATCOM are elaborated in detail.Based on the three-phase instantaneous reactive power theory, the detection methodsof instantaneous reactive current is elaborated systematically. Three phase voltage currentdetection circuit is deigned, and it was simulated about single-phase harmonic circuit inMATLAB/SIMULINK. The fundamental current and harmonic current are separated fromthe power grid. It proves that this method is effective in reactive compensation. Then thethree phase’s current and voltage signal detection circuit and the hardware connectioncircuit are analyzed in detail. Based on the essential principle of SPWM waveform, it ismodeled and simulated in MATLAB/SIMULINK; the three-phase SPWM waveform isgenerated.The core part of this paper is the system control unit, but the sampling accuracy andspeed of the control signal impact on the compensation effect. In order to solve thisproblem, ADS8364is maked use in connecting DSP; it is an AD conversion chip with highprecision, high speed. The sampling channel is controlled by DSP to achieve more accuratedata collection. The paper introduces the working principle and performance of ADS8364and the pin connection with DSP. It degines the signal conditioning circuit. Meanwhile, it introduces the characteristics, application fields and external structure. The last it analyzesand debugged for software in CCS3.3, provides the control flow chart of each part of themodule.It brings about the signal sampling and transformation through the connection withADS8364and DSP. The sampling precision is12bit for the internal AD of DSP, butonly9bit is worked in practice，the sampling time is accurate to milliseconds. However,the ADS8364sampling precision is16bit, sampling time reaches microsecond grade. Itproves that the sampling rate and conversion accuracy are improved through theconnection with ADS8364and DSP; it better meets the demand of reactive powercompensation.