1. A Novel DC Capacitor Voltage Balance Control Method for Cascade Multilevel STATCOM, PE-27(1) Zhao Liu; Bangyin Liu; Shanxu Duan; Yong Kang; Coll. of Electr. & Electron. Eng., Huazhong Univ. of Sci. & Technol., Wuhan, China
Abstract: This paper presents a novel dc capacitor voltage balance control method for cascade multilevel static synchronous compensator (STATCOM) and a general analytical method(解析法)
for balance control strategy. Considering that the imbalance of dc capacitor voltage is caused by the inconsistency of active power absorbed and consumed by chain；有功功率的交换？, a balance
control strategy based on active voltage vector superposition；叠加？is proposed, in which an
active voltage component is superposed；叠加？ to chain's output voltage to change its absorbed
active power. A general analytical method based on vector analysis is also presented, by which the performance of balance control strategy can be analyzed, including stability and regulation capacity. To find out the most appropriate balance control strategy, a comparison still based on vector analysis among the proposed and other two commonly used methods is provided, from
which it can be known that the proposed balance control strategy has the advantage of good stability and strong regulation capacity, and simulations are performed to prove it. The effectiveness of proposed control scheme has been verified ；证实？by experimental results based
on a three-phase 36-chain cascade multilevel STATCOM laboratory prototype. 文章核心，矢量叠加法解决直流电容电压平衡问题。
2. Multigoal Heuristic Model Predictive Control Technique Applied to a Cascaded H-bridge
StatCom , PE-27(3) Townsend, C. D.; Summers, T. J.; Betz , R. E.; School of Electrical Engineering and Computer Science, University of Newcastle, Callaghan, Australia Abstract: A multilevel H-bridge StatCom inherently ；内部的？contains redundancy；冗余？ in
the available switching states. This paper develops a variation on the typical model predictive
control scheme which is able to exploit this redundancy to simultaneously ；同时？balance the
H-bridge capacitor voltages, provide excellent current reference tracking, and minimize converter switching losses. The scheme consists of a dead-beat ；非周期的？current controller that has been
integrated；整合？ with heuristic ；启发式？models of the voltage balancing and switching loss
characteristics. The integration of a pulsewidth modulation scheme is also described. Simulation and experimental results are presented that confirm the correct operation of the control and modulation strategies. Comparison with traditional control and modulation schemes is provided in terms of the key performance indicators associated with multilevel H-bridge StatComs.
3. A Transformerless；不是用变压器的？ D-STATCOM Based on a Multi-Voltage Cascade
Converter Requiring No DC Sources , PE-2011-11, Sano, K.; Takasaki, M.; K. Sano is with
System Engineering Research Laboratory Central Research Institute of Electric Power Industry 2-11-1, Iwado Kita, Komae-shi, Tokyo, 201-8511,
Abstract: This paper deals with a cascaded multilevel converter which has multiple dc voltage
values (multi-voltage cascade converter, or hybrid multilevel converter) for a 6.6-kV transformerless distribution static synchronous compensator (D-STATCOM). A control method is proposed to realize dc voltage regulation of series-connected multiple cells in the STATCOM operation, making it possible to remove dc sources from all H-bridge cells. The simplified
configuration；结构？ without the dc sources makes the STATCOM small and lightweight. A downscaled ；规模缩小的？STATCOM model rated at ；额定？220 V and 10 kVA is built and a
series of verification tests is executed. Theoretical analysis and experimental results prove the stable operating performance of the proposed method in steady states and transient ；稳态和瞬
4. Fault-Tolerant Design and Control Strategy for Cascaded H-Bridge Multilevel Converter-Based STATCOM , IE-57(8), Wenchao Song; Huang, A.Q.; Dept. of Electr. Eng., North Carolina State Univ., Raleigh, NC, USA
Abstract: Cascaded H-bridge multilevel converter (CHMC) is a promising topology for flexible ac transmission systems such as static synchronous compensator (STATCOM) applications. Attention was drawn to the issue of converter reliability due to the large number of power devices
used in CHMC applications. This paper proposed an effective fault-tolerant strategy by using
H-bridge building block (HBBB) redundancy；冗余？ in CHMC-based STATCOM. The operating
principle and the control strategy of the fault tolerance are proposed and discussed. The controller design consideration for the fault-tolerant STATCOM is presented. The proposed fault-tolerant control strategy is implemented on a seven-level CHMC-based STATCOM simulation platform and a five-level CHMC-based STATCOM hardware prototype. Simulation and experimental results are illustrated to verify the feasibility of the proposed fault-tolerant design with the HBBB redundancy.
5. Fault Detection and Mitigation in Multilevel Converter STATCOMs
IE-58(4), Yazdani, A. ; Sepahvand, H. ; Crow, M.L. ; Ferdowsi, M. ; Quanta Technol.,
Raleigh, NC, USA
Many static synchronous compensators (STATCOMs) utilize multilevel converters due to the following: 1) lower harmonic injection into the power system; 2) decreased stress on the electronic components due to decreased voltages; and 3) lower switching losses. One disadvantage, however, is the increased likelihood of a switch failure due to the increased number of switches in a multilevel converter. A single switch failure, however, does not necessarily force an (2n + 1)-level
STATCOM offline. Even with a reduced number of switches, a STATCOM can still provide a significant range of control by removing the module of the faulted switch and continuing with (2n
- 1) levels. This paper introduces an approach to detect the existence of the faulted switch, identify which switch is faulty, and reconfigure the STATCOM. This approach is illustrated on an eleven-level STATCOM and the effect on the dynamic performance and the total harmonic distortion (THD) is analyzed.
6. Negative-Sequence Reactive-Power Control by a PWM STATCOM Based on a Modular Multilevel Cascade Converter (MMCC-SDBC), Akagi, H. ; Hagiwara, M. ; Maeda, R. ;
H. Akagi is with the Department of Electrical and Electronic Engineering Tokyo Institute of Technology, Tokyo, Japan.(email@example.com),IE-2011-12
This paper presents the application of a modular multilevel cascade converter based on single-delta bridge-cells (MMCC-SDBC) to a STATic synchronous COMpensator
(STATCOM),particularly for negative-sequence reactive-power control.The SDBC is
characterized by cascade connection of multiple single-phase H-bridge (or full-bridge) converter cells per leg,thus facilitating flexible circuit design, low voltage steps, and low electro-magnetic interference (EMI) emissions. This paper designs, constructs, and tests a 100-V 5-kVA PWM STATCOM based on the SDBC, with focus on the operating principle and performance. Experimental results verify that it can control not only positive-sequence reactive power but also negative-sequence reactive power and low-frequency active power intended for flicker compensation of arc furnaces.
7. Cascade multilevel static synchronous compensator configuration for wind farms PE,IET 4(5) Jayasingha, S.D.G. ; Vilathgamuwa, D.M. ; Madawala, U.K. ; Sch. of Electr. &
Electron. Eng., Nanyang Technol. Univ., Singapore, Singapore
Modulation and control of a cascade multilevel static synchronous compensator (STATCOM) configuration to improve the quality of voltage generated by wind power systems are presented. The proposed STATCOM configuration needs only four dc-link capacitors and 24 switches to synthesise nine-level operation. In addition to that, switching losses are further reduced by splitting the voltage source inverter of the STATCOM into two units called the `bulk inverter` and the `conditioning inverter`. The high-power bulk inverter is operated at low frequency whereas the low-power conditioning inverter is operated at high frequency to suppress harmonics produced by the bulk inverter. Fluctuations at the point of common coupling voltage, caused by sudden wind changes, are suppressed by controlling reactive power of the STATCOM. Simulation and experimental results are presented to verify the efficacy of the proposed modulation and control techniques used in the STATCOM.