Abstract: The present disclosure provides an optical aluminum alloy and a preparation method thereof. The preparation method includes the following steps: step S1, preparing an original aluminum alloy cast ingot from raw materials by adopting a semi-continuous casting process; step S2, subjecting the original aluminum alloy cast ingot to homogenization, head and tail cutting and skin turning, to obtain a surface treated alloy raw material; step S3, subjecting the surface treated alloy raw material to rapid solidification treatment through a melt spinning method to obtain a rapid solidification alloy strip; step S4: subjecting the rapid solidification alloy strip to crushing treatment and then to sheathing and cold pressing, to obtain a cold pressed blank; step S5, subjecting the cold pressed blank to 1-2 passes of hot extrusion procedures to prepare a bar; and step S6, subjecting the bar to solution treatment and aging treatment, to obtain the finished aluminum alloy material.

Abstract: A winding switching signal generator is configured to obtain information indicating a degree of field weakening from at least one of a current command calculator and a constant output controller, and to generate a winding switching signal for switching from a low speed rotation state to a high speed rotation state when the degree of the field weakening exceeds a predetermined condition in the low speed rotation state.

Abstract: An inverter device according to an embodiment includes a constant power controller. The constant power controller computes and outputs, when a value of a voltage reference to an AC motor exceeds a predetermined threshold value, a d-axis current reference correction value on the basis of the value of the voltage reference and the predetermined threshold value. Moreover, the constant power controller generates the d-axis current reference correction value by using a constant power model determined by a torque reference or a speed reference and a supplied direct voltage at an output switching timing determined based on a winding switching signal and outputs the d-axis current reference correction value for a predetermined time.

Abstract: A winding switching signal generator is configured to obtain information indicating a degree of field weakening from at least one of a current command calculator and a constant output controller, and to generate a winding switching signal for switching from a low speed rotation state to a high speed rotation state when the degree of the field weakening exceeds a predetermined condition in the low speed rotation state.

Abstract: An inverter device according to an embodiment includes a constant power controller. The constant power controller computes and outputs, when a value of a voltage reference to an AC motor exceeds a predetermined threshold value, a d-axis current reference correction value on the basis of the value of the voltage reference and the predetermined threshold value. Moreover, the constant power controller generates the d-axis current reference correction value by using a constant power model determined by a torque reference or a speed reference and a supplied direct voltage at an output switching timing determined based on a winding switching signal and outputs the d-axis current reference correction value for a predetermined time.