Brushless direct current motor control system based on electrolytic capacitor-free inverter and control method

Abstract

The invention discloses a brushless direct current motor control system based on an electrolytic capacitor-free inverter and a control method. The method comprises the steps of detecting system input voltage, bus current, motor speed and a motor rotor position; carrying out error adjustment on given rotating speed and actual rotating speed; calculating bus given current according to the input voltage, speed ring output and a thin-film capacitor capacitance value; calculating bus error current, and carrying out PI adjustment, thus obtaining a duty ratio controlled by square wave PWM; obtaining a square wave PWM drive signal according to the duty ratio, the motor rotor position and a commutation logic; modulating the inverter for controlling a motor. According to the brushless direct current motor control system based on the electrolytic capacitor-free inverter and the control method provided by the invention, the application of the electrolytic capacitor-free inverter in the brushless direct current motor control system can be realized, a grid side high power factor is acquired, a control structure is simplified, and the system reliability is improved.

Description

technical field [0001] The invention belongs to the technical field of AC variable frequency drive, and more specifically relates to a brushless DC motor control method based on an electrolytic capacitor inverter. Background technique [0002] Brushless DC motors have been well developed in industries such as automobiles, aerospace, and household appliances due to their high efficiency, long life, good speed-torque characteristics, simple control, and wide speed range. It has become a research hotspot of scholars from all over the world. [0003] Household appliances such as air conditioners, whose input voltage is single-phase AC, and the pre-stage circuit is a single-phase uncontrolled rectifier bridge, the bus voltage is prone to fluctuations, causing harmonic pollution and power factor drop. my country's 3C certification and European CE certification have clear regulations on the current harmonics of household air conditioners. For systems with each phase current less t...

AI Technical Summary

Problems solved by technology

[0004] At present, the commonly used power factor correction schemes for household appliances mostly adopt BOOST circuit topology. Because the circuit contains power devices, switching losses are introduced, and the control circuit is relatively complicated.

At the same time, the large-capacity DC bus capacitor in the circuit is greatly affected by temperature, has a limited service life and low system reliability

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