Industrial Technology Research Institute

Hsing-Cheng Yu

Shyh-Jier Wang

Li-Te Kuo

Tzung-Yuan Lee

Shir-Kuan Lin

Hsing-Yu Lin

A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60&#xb0; is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30&#xb0;, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30&#xb0;&#x2212;&#x394;&#x3b8; and 30&#xb0;+&#x394;&#x3b8; are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Sensorless driving method for brushless DC motor

A method and an apparatus for estimating the position of a moving part of a linear actuator are provided. The method comprises the following steps. Move the moving part towards a target position. Receive magnetic signals generated by the magneto-resistive sensor of the linear actuator, which include a sine signal and a cosine signal. Then, generate a first square wave, a second square wave, and a regional square wave based on the sine signal and the cosine signal. Generate a saw-tooth wave based on the sine signal, the cosine signal, the second square wave, and the regional square wave. Next, calculate the number of regions which the moving part is across from the origin point based on the first square wave, the second square wave, and the regional square wave. Finally, estimate the current position of the moving part based on the saw-tooth wave and the number of regions.

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Hsinchu County, Taiwan

Hsing-Cheng Yu