Background: A leading international manufacturer of industrial water purification equipment uses, as an integral part of the process, a DC power supply that is used to drive ions in the water through a permeable membrane. The volume of water purified by the process is directly proportional to the electrical power available to drive the ions through the membrane. Conventional power supplies have either constant voltage or constant current outputs. In either case, a change in the load causes a change in the output power.

Project: Product Resources designed a 1.5 kilowatt power supply which automatically compensates for changes in the electrical load caused by changes in the salinity of the feed water, yet maintains constant output power. The Product Resources design consists of a switching series regulator with a feedback circuit that responds to a change in load impedance by adjusting both voltage and current simultaneously. This enables one power supply to deliver the low voltage and high current required for high salinity water and automatically adjust to high voltage and low current as the salinity drops. The Product Resources power supply is able to replace no less than seven different models of conventional power supplies at a very competitive cost. Immediate advantages are increased water production efficiency and the replacement of a significant inventory of power supplies with one model.

Technologies: integral kilowatt linear power supplies, high current transistor switching DC-DC regulators, analog feedback circuits, isolated DC current measurement, sheetmetal work, corrosive operating environments

Back to Engineering Design Services