英文原文SVPWM Switched DSTATCOfor Power Factor and Voltage SagCompensationBishnu P. Muni, S. Eswar Rao, and JVR VithalAbstract：In a power distribution network of a power utility or industry, the reactive power management plays a major role in reducing distribution loss and maintaining constant distribution voltage. Voltage source PWM inverter based reactive power generator has fast response to reactive power demand and hence can be used for power factor improvement and voltage support. With the availability of new generation DSPs with inbuilt event manager module, the space vector PWM(SVPWM) switching patterns can be generated easily. This paper proposes SVPWM switched DSTATCOM for power factor and voltage sag compensation. The paper presents the simulation studies on SVPWM switched DSTATCOM in power factor control mode. It also gives the mathematical model of DSTATCOM in voltage sag compensation mode. The simulation results show that the space vector PWM strategy can be used for power factor and voltage compensation. Further, experimental studies on SVPWM switched DSTATCOM have been presented to validate the control philosophy.Index Terms： DSTATCOM, DSP control, Reactive power compensation, SVPWM, Voltage Sag.I. INTRODUCTIONThe industrial loads with low power factor cause excessive loading of the distribution transformer and low voltage at the point of common coupling (PCC). The distribution static synchronous compensators (DSTATCOM) can help in generating leading reactive volt-ampere (VAR) at the PCC and avoid the problems associated with the low power factor 1. The availability of high power self commutating semiconductor devices, new control philosophies and high performance computing elements, like, micro-controller and DSP, are revolutionizing the electric power transmission and distribution systems. Shunt connected, PWM converter based DSTATCOM are gaining popularity for improving power factor and power quality in industrial premises. In addition to the reactive power compensation, the DSTATCOM can also act as active filter or load conditioner to improve the power quality. DSTATCOM are generally used for reactive power management in distribution network with highly fluctuating loads, like arc furnace, rolling mills or high power induction motors, induction machine based wind electric generator, voltage regulation in distribution network etc.Momentary power interruptions and voltage sags are most important power quality problems affecting industrial and large commercial customers. Voltage sags cause the malfunction of the modem process control, programmable logic control, and variable speed drives. Voltage sags can initiate tripping off for voltage-sensitive loads. Voltage sags are usually associated with a fault somewhere on power system network. Voltage sags are much more common since they can be associated with faults remote from the customer. Motor starting also results in voltage sags but the magnitudes are usually not severe enough to cause equipment malfunction. VSC based series compensators are the ideal choice for voltage sag compensator. DSTATCOM are the most preferred device for voltage flicker compensation. Reference 6 presents the experimental study of advanced static VAR compensator for voltage sag mitigation. Kalman filter based unified approach for voltage sag and voltage flicker mitigation with DSTATCOM has been reported 7.In a DSTATCOM, the voltage source is normally controlled with hysteresis or ramp comparison type current regulated PWM inverter 1-4. The hysteresis and ramp comparison type current regulated PWM inverter can be implemented with conventional analog and digital circuit. The PWM switching pattern for DSTACOM can also be generated by comparing phase shifted reference voltage signal generated PLL and associated circuitry with triangular carrier wave. The application of SVPWM for DSTACOM is not explored fully. SVPWM technique offers several advantages like higher output voltage (15% more than conventional sine - triangle modulation technique and hence, better utilization of DC link), lower harmonics contents and suitability for complete digital implementation with new generations DSPs.This paper presents a novel DSTATCOM with SVPWM technique for generation of PWM pattern. The suitability of SVPWM technique for reactive power management in DSTATCOM has been verified by simulation by using SimPower System of MATLAB and Simulink. Further, the control logics for DC link voltage control, reactive power generation and PWM paper generation with SVPWM. technique have been implemented on TMS320F240 based control card. Further, this paper also presents the mathematical analysis of DSTATCOM for voltage sag mitigation.The paper has been organised in five sections. The second section gives the control methodology for power factor compensation and brief introduction of SVPWM technique; the third section gives modelling of DSTATCOM and simulation result