A phase shifted-pwm d-statcom using a modular multilevel cascade converter (ssbc)—part i modeling, analysis, and design of current control,2015 Power Electronics Projects Training
Contact: IIS TECHNOLOGIES
A phase shifted-pwm d-statcom using a modular multilevel cascade converter (ssbc)—part i modeling, analysis, and design of current control
A Phase-Shifted-PWM D-STATCOM Using a Modular Multilevel
Cascade Converter (SSBC)—Part I: Modeling, Analysis, and Design of
No: 40, C-Block,First Floor,HIET Campus,
North Parade Road,St.Thomas Mount,
Chennai, Tamil Nadu 600016.
Landline:044 4263 7391,mob:9952077540.
• This project presents and discusses a phase shifted- PWM distribution static synchronous
compensator (D-STATCOM) using the modular multilevel cascade converter based on single-star
bridge cells (MMCC-SSBC).
• An analytical model for the phase-shifted PWM is proposed to design the current control gains.
• Two phase-shifted PWM methods, which are named as one-cell and all-cells update methods, are
theoretically and experimentally compared.
• Among the MMCC family members, the SSBC is the most basic and suitable for the static
synchronous compensator (STATCOM).
• An SSBC-based STATCOM yields three-phase multilevel voltage waveforms with low voltage steps.
• This results in requiring no shunt harmonic filter at the ac side of the STATCOM. Moreover, the
modularity facilitates an eventual expansion of cascaded bridge cells.
• As a result, when it is applied to power distribution systems with nominal voltages of 6.6 kV in
Japan and 13.8 kV in the U.S., a reasonable compromise between the blocking voltage of
switching devices and the cascaded bridge-cell count per cluster enables to eliminate a medium-
voltage line-frequency transformer from the distribution STATCOM (also known as D-STATCOM).
However, since the SSBC-based D STATCOM installs a split and floating dc capacitor on the dc side
of each bridge cell, it is mandatory to keep all of the mean dc capacitor voltages regulated and
• This project achieves general modeling and analysis of current control in an SSBC-based D-
STATCOM intended for a distribution system, considering a time delay caused by phase-shifted
• As the bridge-cell count gets higher, the all-cells update method can reduce the time delay more
significantly than the one-cell update method.
• A three-phase downscaled SSBC-based D-STATCOM is designed, constructed, and tested to
confirm the validity and effectiveness of the modeling, analysis, and design. The D-STATCOM
consists of six cascaded bridge cells per cluster.
• This project includes experimental comparisons in current control performance between the all
cells and one-cell update methods.
• Transient waveforms obtained from the experiment agree well with those from the computer
simulation using a software package of PSCAD/ EMTDC.
TOOLS AND SOFTWARE USED
• MP LAB