Custom geometries solutions for motor drive industry - Energy
Motors are widely utilized in household, commercial and industrial applications from moving gas and liquids, as in fans and pumps, to powering hand tools and heavy equipment. Automotive industry is also increasingly using traction motors for powering wheels. In many cases, an adjustable speed is required to accommodate changing needs. This is accomplished with a motor controller / motor drive in which a DC-AC converter chops up a DC input signal into discrete steps to create a custom AC waveform, with the desired frequency.
The resulting AC waveform produced by the switching action of the converter consists of sharp voltage rise and fall, which creates higher level harmonics that put a strain on the motor winding and produce unwanted EMI. An output filter with a smoothing inductor is used to mitigate this.
Common inputs for motors may be AC from 60Hz power grid or DC from solar power, fuel cells or battery pack. AC input would require conversion to DC before the DC-AC converter stage for speed control, as well as input filtering and power factor correction, with corresponding magnetics.
The ideal smoothing inductor can provide inductance at low cost, low core loss at motor frequency (<20Hz ~ 200Hz) and switching frequency (2kHz~<20kHz typical), with low leakage flux to minimize EMI and eddy current losses in the windings. Since operating frequency is within the audio range, a low magnetostriction material would introduce minimal additional noise.
Micrometals powder cores with their distribution gap structure are ideal in minimizing leakage by precluding the need for a large localized discrete gap and its accompanying fringing leakage flux. Micrometals also produce several cost effective materials, such as Sendust, with low to near zero magnetostriction. The higher saturation of powder cores (>8 to >10 kilogauss) compared to ferrites allow greater size reduction.
Typical Applications with Inductive components:
- AC Inductor – Differential-Mode Input Filter
- Power Factor Correction Inductor
- AC Inductor – DC-AC Inverter, Variable Speed Drive, Output Filter
To contact our engineering group regarding Micrometals solutions for Motor Drive applications please use our website contact form or send an e-mail to email@example.com