Position-sensorless control device for wide speed regulating range brushless DC motor without filter

Abstract

The invention relates to a filter-free brushless DC motor control device with wide speed regulation range and no position sensors. The filter-free brushless DC motor control device comprises a DC power supply, a three-phase inverter, a brushless DC motor, a rotor position detection circuit, a microcontroller and a three-phase inverter power device drive circuit, wherein the DC power supply is connected with the brushless DC motor through a power voltage regulating unit and the three-phase inverter; the output signal of a rotor position detection circuit connected with the brushless DC motor is directly connected with the A / D conversion input pin of the microcontroller; ant the PWM output signal of the microcontroller is connected with the power voltage adjusting unit through a power voltage adjusting unit power device drive circuit. The control device can control the rotation speed of the brushless DC motor by PWM chopping control of a power switch VT7. Six commutation control signals outputted by the microcontroller are connected with the three-phase inverter through the three-phase inverter power device drive circuit to achieve commutation control of the brushless DC motor. The filter-free brushless DC motor control device has the advantages of improved reverse potential detection accuracy of the brushless DC motor, simplified system and lowered cost.

Description

Technical field: [0001] The invention relates to a position sensorless control device for a brushless direct current motor, in particular to a position sensorless control device for a brushless direct current motor with a wide speed regulation range without a filter. Background technique: [0002] In the conventional brushless DC motor position sensorless control device, the motor rotor position signal is obtained indirectly by detecting the motor disconnected phase winding terminal voltage to obtain the motor rotor position signal, which has the characteristics of simple structure, low cost, and convenient implementation. , has been widely used in industrial practice. The structure of conventional brushless DC motor without position sensor control device is as follows: figure 1 As shown, its main circuit is as figure 2 shown, where VT 1 ~VT 6 A bridge inverter circuit 2 is formed; A, B, and C are respectively the three-phase windings 3 of the brushless DC motor. In th...

AI Technical Summary

Problems solved by technology

The common defects of these detection methods are: due to the relatively weak amplitude of the back EMF signal during low-speed operation, coupled with the influence of PWM modulation, it is difficult to accurately detect the zero-crossing point of the back EMF, resulting in the low-speed operation of the brushless DC motor position sensorless control system. The scope and performance are not ideal, and it also seriously limits the application and promotion of the brushless DC motor sensorless control system in the above fields

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