A low-cost digital control scheme for Brushless DC motor drives in domestic applications

Electric motors are an integral part of industrial plants with no less than 5 billon motors built worldwide every year. Residential and commercial appliances such as refrigerators and air conditioning systems have been using conventional motor drive technology. The machines in these applications typically have low efficiencies and high maintenance. Brushless DC (BLDC) drives are known for higher efficiency, lower maintenance and higher cost. In a market driven by profit margins, the appliance industry is reluctant to replace the conventional motor drives with the advanced motor drives (BLDC) due to their higher cost. Therefore it is necessary to have a cost-efficient, but effective BLDC motor controller. This paper lays the groundwork for the development of a new low-cost IC for control of BLDC motors. A simple novel digital pulse width modulation (PWM) control has been implemented for a trapezoidal BLDC motor drive system. Due to the simplistic nature of this control, it has the potential to be implemented in a low cost application specific integrated circuit (ASIC). The novel controller is modeled and verified using simulations. Experimental verification is carried out using Field Programmable Gate Arrays (FPGA) to validate the claims presented.