A Phase-Shifted PWM STATCOM Using the Modular Multilevel Cascade Converter (MMCC-SSBC)

Current control of modular multilevel converters with phase‐shifted pwm using a daisy‐chained distributed control system

“…Sampling all the voltage references at the peak and bottom of all the carriers as shown in the figure ensures good control performance. The sampling period T S is defined as …”

“…The current control model of the MMC using the phase‐shifted PWM considering the reference sampling was reported in ; however, the daisy‐chained controller system and the communication delay were not included in the past discussion. We discuss and reveal the current control model considering the stepwise delays caused by the communication delay and the reference sampling, which is obtained in the previous section.…”

“…This allows us to consider that the inductor integrates the average voltage during the sampling period T S as shown in Fig. (b) . The integrated value is from the relationship between voltage and current in the inductors.…”

“…Figure presents the step responses with various current control gain K C and types of control system. In the model of the centralized control, the phase‐shifted PWM was also assumed and all the cells were assumed to sample the voltage reference in the equivalent switching frequency with no communication delay. The numbers of sample delays N S n ( n = 1 – 4) were set at zero for the case without the communication delay; hence, the closed‐loop pulse transfer function of the current control with the centralized control was determined as follows from (14): …”

“…This article describes a current control of an MMC with a phase‐shifted pulse width modulation (PWM) using the daisy‐chained distributed control. We theoretically reveal the current control model considering the stepwise lagged output caused by the communication delays.…”