Brushless DC motor drive

摘要

A brushless DC motor drive is disclosed which includes drive and control circuitry incorporated into an integrated drive unit. The drive circuitry includes a ground offset or signal conditioning circuit which receives command input signals from a command device and corrects for variations in ground potential between the power source and to the drive. The corrected command signal is used for closed-loop velocity control of a brushless DC motor. The signal conditioning circuit also provides a reference voltage signal for use by a controller which controls the drive circuitry. The command input signal is also applied to an energy conservation circuit. The circuit applies power to the control circuit only when the command is above a preset threshold. When the command is below the threshold level, power is interrupted to the control circuit to reduce the energy consumption of the system.