Low-ripple driving method of alternating-current motor

Abstract

The invention discloses a low ripple driving method of an alternating current motor. An adopted power topological structure comprises a high-frequency power switch, a high-frequency diode and a high-frequency direct-current filter inductor, six low-frequency power switches are connected with six low-frequency diodes and three alternating-current filter capacitors in series, and the rotor position,the speed, the stator current and the preceding-stage inductive current of the alternating-current motor are detected. During control, the current amplitude is controlled through high-frequency chopping of the high-frequency power switch, and the current phase is adjusted through the low-frequency power switch. According to the invention, the high-frequency power switch carries out high-frequencychopping, thereby facilitating the reduction of current ripples, and reducing the size of an inductor. The direct-current filter inductor realizes voltage stabilization without a large capacitor; theadoption of the low-frequency power switch is beneficial to the reduction of system cost and switching loss; the alternating-current filter capacitor improves the current harmonic performance and reduces adverse effects caused by high dv / dt; a post-stage control scheme with a constant modulation ratio facilitates the application of various modulation strategies.

Description

technical field [0001] The invention relates to a low-ripple driving method for an AC motor, which belongs to the technical field of electric power transmission. Background technique [0002] The traditional AC power transmission system usually directly drives the AC motor by a general-purpose or special-purpose frequency converter, but the performance of the traditional frequency converter is limited, and it is difficult to meet the motor drive of higher performance occasions. There are mainly the following problems: On the one hand, the output current of the traditional frequency converter Large harmonics will further increase the loss of the stator and rotor, resulting in serious heat generation, and will lead to aggravated torque ripple and increase the difficulty of motor control; on the other hand, the output dv / dt of the traditional inverter is very high, and there is serious electromagnetic interference , Further damage the motor insulation and bearings, reducing the...

AI Technical Summary

Problems solved by technology

[0002] The traditional AC power transmission system usually directly drives the AC motor by a general-purpose or special-purpose frequency converter, but the performance of the traditional frequency converter is limited, and it is difficult to meet the motor drive of higher performance occasions. There are mainly the following problems: On the one hand, the output current of the traditional frequency converter Large harmonics will further increase the loss of the stator and rotor, resulting in serious heat generation, and will lead to aggravated torque ripple and increase the difficulty of motor control; on the other hand, the output dv / dt of the traditional inverter is very high, and there is serious electromagnetic interference , further damage the motor insulation and bearings, reducing the system reliability

[0006] (3) High-frequency switching devices are used, but the problems of high cost and electromagnetic interference cannot be ignored;

Images