A new method for efficient drive and current control of small-sized brushless DC motor: Experiments and its evaluation

In the low inductance and small-sized brushless DC motor, the conventional PWM driving method makes relatively large copper loss because of an unintended directional transition current caused by ordinary complementary switching in the halfbridge circuits. We implemented the experimental feedforward current control system based on the method proposed by us in which the bridge circuits are driven non-complementarily to improve the power efficiency based on the circuit analysis and measured an actual power consumption. In the experimental system, driving circuits and micro controller are existing products in which control software is replaced, without current pickup circuit. In this paper, we report on the detail of the implementation and results of experiments on the real small-sized motor. And also the discussions on the effectiveness of proposed method is given.