Research on EMI Based on Automobile DC Brushed Motor

Abstract

Automobile seat motor, as a commonplace component in the automotive electric seat system, is more and more widely used in passenger vehicles in their automotive seat. Based on the existing method of controlling system and consideration from the minimum cost perspective, in present automotive seat controlling system, automobile manufacturers all use DC (Direct Current) brushed motors as the executing components of the electrified seat control system. DC brushed motors adopts PWM (Pulse Width Modulation) modulation method on the H-bridge as a controlling strategy in order to control the revolution. Compared with DC brushless motors, DC brushed motors are fast in start-up, timely responsive with smooth slope of speed modulation, easily controllable and low-cost. However, the drawback to the brushed motors is also evident: due to the existence of electric brushes and commutators, brushed motors are usually complicated in structure, poor in reliability, filled with faults and excessive repairing workload, and short in working life; more importantly, sparkles by commutators in brushed motors usually creates electromagnetic interference. This article is based on the automobile seat motors to investigate the electromagnetic compatibility (EMC) problems caused by the operation of DC brushed motors and try to find some improvement solution. KEYWORDS