Vacuum pump and motor controller

Abstract

A vacuum pump and a motor controller that make a safe transition to a regeneration mode while avoiding an overvoltage are provided. A turbo molecular pump includes a power supply unit that converts alternating-current power to direct-current power and outputs the power, the alternating-current power being obtained from an alternating-current power supply, and the motor controller that controls a motor. The motor controller includes: a motor driving circuit that drives the motor when receiving direct-current power or regenerated power; a backflow prevention diode interposed between the power supply unit and the motor driving circuit; a power-failure detection circuit that detects a primary voltage of the backflow prevention diode; a driving-voltage sensing circuit that detects a secondary voltage of the backflow prevention diode; and a motor control circuit that determines, when the primary voltage drops to a predetermined power-failure detection threshold value, whether a power failure is a primary power failure of the alternating-current power or a secondary power failure of the direct-current power based on a voltage difference between the primary voltage and the secondary voltage, and controls the motor driving circuit so as to enter a regeneration mode.