Power electronic interfaces for low voltage residential networks

Abstract

A proposal to increase the existing residential LV grid voltage from 230 V to 300 V has been made in order to increase existing network capacity. A power-electronic AC-AC converter is then used to provide 230 V at each property. The equipment can also provide power-quality improvements to the network and load. Several constraints such as temperature rise at the converter location lead to a converter design requiring very high efficiency. In this paper different AC/AC converter topologies are presented which compares the power quality benefits, size and efficiency of each converter. The design and the control technique of the most suitable topology are verified using simulation and preliminary experimentally results of prototype hardware are also included.

Protection issues in the presence of power electronic converters in smart LV residential networks

“…A simple, low‐cost, low size/weight circuit, which also has a continuous neutral is the AC chopper shown in Figure 9, which was the chosen candidate for the PEC application [14,25].…”

“…This then precludes many traditional power electronic circuits, for example the so-called back-to-back AC/DC converter with sinusoidal pulse-width modulation is shown in Figure 8, which has a discontinuous neutral conductor. A simple, low-cost, low size/weight circuit, which also has a continuous neutral is the AC chopper shown in Figure 9, which was the chosen candidate for the PEC application [14,25].…”

“…This requires an additional voltage transducer VT i to detect the input voltage polarity, which is used to control the PWM and dead time sequencing logic. An alternative method uses the polarity of the output current fed from the current transducer CT , or a more robust function uses both input voltage and output current polarity [25].…”

Thermal aspects of a low cost power electronic converter for high capacity, smart residential distribution networks

“…Previous work [4,5] has shown that a bi-directional, AC chopper circuit using SiC MOSFETs is the best candidate to fulfil the above requirements for the PEC, as it requires a minimum number of transistors in the main power path and has a very simple structure and control requirement. The AC Chopper consists of two bi-direction switches.…”

“…This system will not only increase network capacity, but also overcome the problem of network over-voltages within a customer's premises caused by a high penetration of DG. The overvoltage problem is mitigated since the PEC can be used to regulate the voltage on the customer side to 230 V. As well as these desirable characteristics the PEC can also enable optimised connections for emerging EV charging, DG and energy storage -the so-called "smart-grid" [3,4,5]. The main objective of the project is the small-scale demonstration of several PECs deployed on part of a residential network.…”