Analysis of the Angle Modulated Switching Strategy for use With Fractional Horse Power BLDC Motors

In recent years, electromagnetic compatibility (EMC) has become progressively important because of the rise in the number of electronic auxiliary devices in motor vehicles. This article presents an angle modulated switching strategy for fractional horsepower drives. It allows decreasing the size of the necessary EMC filter, for the example case drive used, down to less than 50%, from nine to four capacitors. Simultaneously, it reduces the radiated electromagnetic emissions over a wide frequency range by almost 10\,\text{dB}_{\mu \text{V/m}}. The EMC measurements performed in a shielded chamber are compared with the results for two conventional switching strategies. Subsequently, the influence of the presented switching strategy on the efficiency and on the emitted airborne and structure-borne noise is investigated.