Research On C+DSTATCOM In Dynamic Reactive Power Compensation

With the rapid economic development, more and more power quality problems become along with the increasing electricity load. DSTATCOM (Distribution Static Synchronous Compensator) is an important reactive power compensation device, By injected the requirements of capacitive or inductive current to the grid can significantly inhibit the grid voltage flicker, improve unbalanced system voltage, improve the power factor. This paper studies the control method of the DSTATCOM for distribution network reactive power compensation, and analysis of the DSTATCOM for oil well pumping unit dynamic reactive power compensation.Analysis the advantages and disadvantages of the two kinds bridge circuit (voltage and current)which is used by DSTATCOM in view of the comparison between the two circuits, in this article we using the voltage-bridge circuit. Otherwise, We can drawn that DSTATCOM has obvious advantages by comparison with the SVC traditional reactive power compensation device.Using the switch function method to establish a mathematical model of the DSTATCOM and described in detail the working principle of the DSTATCOM. Compensation current real-time and accuracy is one important indicator of good or bad performance of DSTATCOM compensation based on instantaneous reactive power theory algorithm ip-iq detection system reactive current. The paper design of an improved reactive current detection based on virtual symmetrical three-phase system, the grid voltage phase unbalance conditions accurately detect the reactive current in the grid. Meanwhile, in-depth study of DSTATCOM control strategy, in order to reduce the switching frequency and switching losses, we use three-leg two-level inverter main circuit structure, the compensation current the generation of direct current control hysteresis control based on space voltage vector hysteresis tracking control.In order to verify the accuracy of the control method, the proposed controller is simulated by Matlab/Simulink, the results show that the proposed control strategy can achieve fast dynamic pumping unit load reactive current compensation, through the load characteristics of the oil well pumping unit, operating status, and traditional pumping unit reactive power compensation device in compensation for the problems detailed analysis on the basis of a balanced capacitors, low cost, large capacity can quickly reactive power compensation and DSTATCOM hybrid modular dynamic reactive power compensator that C+DSTATCOM. In additional, the hardware circuit is designed using the TMS320C6747of TI, including starter circuit, sampling circuit and IGBT drive and protection circuit, The software design of the device, including the main program of the process design and the modular design of each subroutine.