The Design And Research Of Intelligent Capacitor Control System Based On DSP

In the power system, the load is inductive and needs to provide a large amount of reactive power, the transmission of reactive power will increase the line loss, the power supply capacity will also be increased.Therefore, the reactive power compensation technology is adopted to avoid the long distance transmission of reactive power from the point of reducing the power loss and improving the voltage quality of the network.The paper research the reactive power compensation device of low-voltage capacitor with DSP TMS320F2812 as controller,monitoring the signal of the power grid in real time,calculating electric parameters and input device when the voltage of switch reaches zero,cut off the device when the current of switch reaches zero according to concerned control strategy.Then the reactive power compensation device will compensate reactive power with rapid and no inrush.We can group many devices in a cordwood system through intercommunication when the load changes in a large range which needed dynamic reactive power compensation,achieving large capacity reactive power compensation by flexible combination.This paper mainly includes two aspects of hardware design and software design.The hardware design mainly includes: voltage and current sampling and conditioning circuit, synchronous square wave circuit, RS-485 communication circuit,switch switching circuit, power circuit, and man-machine interface.In software, use C programming language according to the principle of modular design.At the same time,the integrated control strategy is adopted to avoid the light load oscillation.The paper selects the composite switch as switching device which connecting double coil magnetic holding relay and thyristor in parallel.The double coil magnetic holding relay does not require the polarity of the conversion circuit to drive, making the circuit simple and reliable.At the same time, it can avoid the loss of the thyristor normal conduction which need to use a large area of heat sink.Finally, simulate and analyze the reactive power compensation device with MATLAB,verify the intelligent capacitor control by experiments.In the practical engineering application, it can adapt to the demand of dynamic reactive power compensation.