Reduction in Harmonics of BLDC Motor Drive Using Controlled LC Filter

Brushless DC (BLDC) motor drives have witnessed an increasing demand in recent times for various industrial applications. One of the main advantage of these motors is that they can be controlled in a wide frequency range. Harmonic mitigation plays a vital role in improving the drive performance and further increases the longevity of motor. There are methods which reduce the harmonic distortion but these are limited to a narrow frequency band. This article deals with a novel filter mechanism by introducing a servo controlled inductor instead of fixed LC filters to improve the THD of the drive. The proposed strategy is advantageous over wide frequency range and hence over complete speed range of BLDC motor drives and is verified via simulations using MATLAB/Simulink and experimented on a laboratory setup of a 3 kW, 48 V, 8 pole pair, 400 Hz BLDC motor and a three-phase IGBT-based inverter. TI's DSP TMS320F2812 is used as a central controller to implement the control algorithm. Results presented in this article validate the effectiveness of the proposed strategy.