直流无刷电动机（Brushless DC Motor）是没有电刷和换向器的直流电动机。

结构上是交流同步马达，利用电力电子技术（逆变器）输入交流信号到马达。但这些交流信号不是正弦波，只是双向的直流电，波形没有限制。

较简单的结构是有一枚永久磁铁及两组（四个）线圈，两组线圈轮流开关。永久磁铁是转子，线圈是定子。当磁铁与线圈成一直线的时候，断开该组线圈，启动下一组线圈。

与传统有刷式直流电动机相比，无刷式较为安全和可靠。碳刷长期使用有碳粉，高温环境下，碳粉可能会爆炸。因此，需要定期清理，同时保养成本较高。

Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors that are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor. In this context, AC, alternating current, does not imply a sinusoidal waveform, but rather a bi-directional current with no restriction on waveform. Additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).