Easing future low-voltage congestion with an AC chopper voltage regulator

Future urban distribution networks are likely to become overloaded, resulting in serious faults, due to a predicted increase in clean energy technologies such as heat pump boilers and electric vehicles. This will significantly increase demand by up to double the present demand levels. As a result, unless changes are made to the low voltage (LV) urban distribution network it will be over-stressed in the future. A possible solution to increase the capacity of the LV distribution network is to use point-of-use voltage regulation (PUVR), which increases the line-to-line distribution voltage from 415 V to 600 V. A key advantage of PUVR is that the present conductors do not need to be replaced, which can be expensive and prohibitive in an urban environment. However, when the 600 V supply is received at the end-user, it will need to be converted from 345-V phase to 230-V phase in order to be useable. This can be achieved with a power electronics converter. This presentation discusses two possible converter topologies for this application: the back-to-back inverter and the AC chopper. To make PUVR as attractive an option as possible, the most cost-effective and efficient topology (the AC chopper) was investigated via creation of a hardware prototype. The AC chopper was found to generate a loss of 1.6% to 2% at a peak input voltage of 200 V.