Patent ID: 8080953
Filing Date: 2011-12-20
Classification: H02P

Abstract:
1. A control device for controlling an electric motor having an electromagnetic coil and a permanent magnet, comprising: a drive control unit that performs control for driving the electromagnetic coil; and a regeneration control unit that performs control for regenerating power from the electromagnetic coil, wherein an induced voltage is induced at the electromagnetic coil responsive to movement of the permanent magnet, the induced voltage having a waveform whose polarity is reversed at a π phase point of the waveform, the drive control unit includes an excitation interval setting unit that sets an excitation interval and a non-excitation interval such that voltage is applied to the electromagnetic coil during the excitation interval while not applied to the electromagnetic coil during the non-excitation interval, the excitation interval having a symmetrical shape whose center corresponds to a π/2 phase point of the induced voltage waveform, the non-excitation interval having a symmetrical shape whose center corresponds to the π phase point of the induced voltage waveform, a multiplication unit that calculates a multiplication value by multiplying a signal value of a change signal indicating changes over time and a control value which can be set at a desired value within a specific range; a PWM signal generating unit that generates PWM signals having a pulse width according to the multiplication value by performing PWM control on the multiplication value; a mask circuit that generates drive signals of the electric motor by masking the PWM signal at the non-excitation interval; and an adjustment unit that adjusts both the control value and partition between the excitation interval and the non-excitation interval according to an output power request for the electric motor, the regeneration control unit includes a regeneration interval setting unit that sets a regeneration interval and a non-regeneration interval such that power is regenerated from the electromagnetic coil during the regeneration interval while not regenerated from the electromagnetic coil during the non-regeneration interval, the regeneration interval having a symmetrical shape whose center corresponds to the π/2 phase point of the induced voltage waveform, the non-regeneration interval having a symmetrical shape whose center corresponds to the π phase point of the induced voltage waveform.