Research On DC Voltage Balancing Control Strategy Of Cascade STATCOM

In the power system, both the power generation, transmission or distribution partsrequire stable voltage level for the user to provide a stable, reliable, non-pollution electric energy. Dynamic reactive power compensation is one of the important means to stabilize voltage levels. STATCOM has many advantages, which represents the development direction of reactive power compensation device, caused widespread concern of scholars at home and abroad.This paper main research is suitable for the 6 kv coal mine power supply system of cascade multilevel, studying of the topology structure of fault-tolerant technology.This paper studies the principle of multi-level control, and chooses the carrier phase-shift PWM as the basic control method.This paper studies the commonly used reactive current detection algorithm, putting forward an improved ip-iq detection algorithm of the reactive power and harmonic current. The algorithm does not need phase locked loop circuit, and has the characteristics of high precision, strong real-time, small computation. Research on control method of cascade multilevel STATCOM DC capacitor voltage,putting forward a control strategy of the tability control of a DC side capacitor voltage and the balance control of the total phase within the capacitor voltage. Finally, the paper designed the compensation plan of Henan dongrong three coal mine, validated by simulation.Simulation experiments show that, the proposed reactive current detection algorithm, multilevel converter topology and its control algorithm can be applied to power system reactive power compensation, which has certain practical and engineering implementation significance.