The simulation research of STATCOM based on cascaded multi-level converter

Abstract

Cascaded multi-level converter based STATCOM (CMC-STATCOM), with a topology of modular-cascaded structure, has a wide prospect of applications in both transmission and distribution system. Under the background of application of STATCOM in high voltage power grid, there are many advantages of CMC-STATCOM compared with other kinds of STATCOM. On the basis of mathematical model of main topology, the states feedback decoupled reactive power control strategy based on the d-q coordinate system is studied in this paper, together with the application principle of carrier phase shift PWM modulation method in CMC. The balance of DC bus voltage is a key factor to the stable operation of devices. In this paper, the hierarchical control method is used to achieve a balance of DC bus voltage, and it involves the DC bus voltage overall control and individual control of each cascade module. At last, the simulation results of 10-kV, 1-MVA CMC-STATCOM verify the correctness and effectiveness of the control strategy and modulation method in this paper using PSCAD/EMTDC.

State feedback control strategy and voltage balancing scheme for a transformer‐less STATic synchronous COMpensator based on cascaded H‐bridge converter

“…An imbalance condition may occur in the H‐bridge cells of a CHB converter because of the following reasons: Unequal losses of H‐bridge cells. Measurement errors in voltage/current sensors. Tolerance of passive elements, especially in DC‐link capacitors [18]. In [23], a method has been proposed which distributes the active power among the H‐bridge cells by superimposing the cosine value of grid voltage to the reference modulating voltage of each cell. This method, however, will cause unequal distribution of reactive power and current flow among the H‐bridge cells which affects the equal distribution of power losses among the power switches and the reliability.…”

Design and Implementation of a Modular Multilevel Inverter with FACTS Capability for Wind and PV systems

“…Also, different modulation methods such as sinusoidal pulse width modulation (PWM), selective harmonic elimination, optimized harmonic stepped waveform tech-nique, and space vector modulation were discussed and com-pared. Among all multilevel topologies [6]- [9] , the cascaded H-bridge multilevel converter is very well known for STATCOM applications for several reasons [10]- [12] . The main reason is that it is simple to obtain a high number of levels, which can help the statcom to connect directly to medium voltage grids.…”

A Novel Single-phase Inverter with Distribution Static Compensator Capability for Wind Applications

“…There are a large number of publications on different aspects of H-bridge STATCOM. For instance, [11][12][13] present new control methods for multi-level H-bridge cascaded STATCOMs to improve the power quality. The modular multilevel converter (MMC) was introduced in the early 2000s.…”