Current control of brushless dc motor based on a common dc signal for space operated vehicles

The objective of the paper is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but it requires constant maintenance. In the brushless permanent magnet motors, they do not have brushes and so there will be lesser maintenance. Brushless dc motors are widely used in applications which require wide range of speed and torque control because of its low inertia, fast response, high reliability and less maintenance. This current controlled technique is based on the generation of quasi-square wave currents using only one controller for the three phases. The current control strategy uses a triangular carrier for the power transistors which is simpler and more accurate than any other options. The advantages of this technique are: (a) The stator currents are completely characterized by their maximum amplitude. (b) The three phases are controlled with the same dc component, and then the phase currents are kept at exactly the same magnitude Imax. (c) The dc link current measurement is not required. (d) Phase currents are kept balanced and phase over currents are eliminated.

► In electric traction and most applications, a wide range of speed control is required. ► BLDC motors are used in applications like low inertia, fast response and high reliability. ► Generation of quasi-square wave currents using only one control for three phases. ► Three phases are controlled with the same dc signal and phase currents are kept balanced. ► The design of controllers plays a vital role in CAIR, ARDE and HAL in DRDO.