Power electronic transformer with adaptive PLL technique for voltage-disturbance ride through

Abstract

The power electronic transformer (PET) has recently emerged as a type of power converter. It features the basic functions of power conversion and isolation as well as additional functions related to power quality control. A novel PET for a distribution grid called a flexible power distribution unit is proposed in this paper, and the energy exchange mechanism between the network and the load is revealed. A 30 kW 600 VAC/220 VAC/110 VDC medium-frequency isolated prototype is developed and demonstrated. This paper also presents key control strategies of the PET for electrical distribution grid applications, especially under grid voltage disturbance conditions. Moreover, stability issues related to the grid-connected three-phase PET are discussed and verified with an impedance-based analysis. The PET prototype is tested, and it passes the voltage-disturbance ride-through function. The experimental results verify the power quality control abilities of the PET.

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

“…1.2.2 | LVRT of the modular multilevel converter (MMC)-based PET In Ref. [12], an adaptive phase-locked loop is employed in a small-scale PET, and its efficacy to assist the moderate voltage-disturbance ride through is verified. In Ref.…”

A H-Bridge-Multiplexing-Based Novel Power Electronic Transformer

“…Presently, in the design of power electronic transformers (PET), various universities and institutes [6][7][8][9][10][11][12] have widely adopted the topology depicted in Figure 1. When a PET is employed in distribution networks, the H-bridge can be cascaded to enhance the voltage level of the rectifier when the power semiconductor device's voltage capability is limited.…”