A novel single-phase motor drive circuit topology has been developed at the Power Electronic Systems ERC, with headquarters at Virginia Polytechnic and State University (EEC 9731677), for low-cost, adjustable speed motor drives for heating, ventilation, and air conditioning (HVAC) systems. Throughout the US, fans, pumps, and compressors used in HVACs are mostly powered by constant-speed drives rather than by the more energy efficient adjustable-speed drives because of lower initial capital investment. HVAC systems consume more than 20 percent of the total energy in the world, according to an EPRI report. The use of adjustable speed drives will save over 35 percent of the energy currently used and will help improve indoor air quality and overall system efficiency.