Assessment of the Dynamic Properties of a Brushless Direct Current Motor Drive of a Centrifugal Flow Metering Unit for Bulk Materials

Abstract

The equations of the transition process are derived to relate the flow of a bulk material with the rate of phase change and current of a brushless direct current motor (BLDC). The example of the DVU2M165S brushless direct current motor shows the impossibility of natural organization of oscillatory damped process with a shorter transition process due to a twofold excess of the electromechanical time constant over the electromagnetic one. Under the above-mentioned ratio of the time constants of the BLDC, it is possible to realize an exclusively aperiodic exponential transient process with respect to the current and speed. In case of the DVU2M165S brushless direct current motor, when a single load is applied, the rate of phase change varies within 10%. To reduce the time of the transition process and give oscillating pattern, a controlled short-time voltage boost is required. The use of the DVU2M165S brushless direct current motor as a sensor of a centrifugal flowmeter of loose materials allows extending the measuring range from 5.4 to 21.3 t/h; the actuator impeller radius being 0.9 m within the rate of phase change from 26.16 to 104.7 s^–1.