A method for detecting the initial state of a permanent magnet synchronous motor

Abstract

The invention discloses a method for detecting the initial state of a permanent magnet synchronous motor. The method includes outputting a fixed PWM signal 100 by a microcontroller, sampling the U-phase current Ia in real time through a sampling circuit, recording the maximum value Ia_max of Ia, and respectively recording Ia reaching the adjacent Calculate the time difference ΔT=T2‑T1 for the two Ia_max times T1 and T2; calculate the average value of ΔT ΔT_p, if the Ia obtained by real-time sampling is always a fixed value and does not change in a sine wave, it means that the fan is in a static state; The controller outputs a fixed PWM signal 010, records the time T_U when the PWM signal is changed, samples the V-phase circuit Ib in real time through the sampling circuit, records the time T_V when Ib reaches Ib_max, and calculates the time difference ΔT'=T_V‑T_U; by comparing ΔT' and ΔT_p The size of the motor rotor can be judged by the size of the motor rotor. The present invention can realize the state detection of upwind and upwind through the upper layer software algorithm combined with the existing sampling circuit. It does not need additional circuits and is not limited by the sampling circuit. It is suitable for various sampling circuits. The control system saves a lot of cost.

Description

technical field [0001] The invention relates to the technical field of permanent magnet synchronous motor detection, in particular to a method for detecting the initial state of a permanent magnet synchronous motor. Background technique [0002] Due to its simple structure, high power density, high efficiency, and high power factor, the permanent magnet synchronous motor (PMSM) is currently mostly used in the home appliance industry, and it is most widely used in fan applications. For fan start-up, compared with other applications where the initial state of the rotor is stationary, the initial state of the fan motor rotor cannot be determined at start-up. There are downwind state, headwind state and static state of the wind turbine. Inaccurate judgment of the initial state can easily lead to the failure of the wind turbine to start. The determination of the initial position state of the wind turbine is the difficulty of the current motor control technology. [0003] In trad...

AI Technical Summary

Problems solved by technology

For fan start-up, compared with other applications where the initial state of the rotor is static, the initial state of the fan motor rotor is uncertain at start-up

Fans exist in downwind state, headwind state and static state. Inaccurate initial state judgment can easily lead to fan startup failure. The determination of the initial position state of the fan is the difficulty of current motor control technology.

[0003] In the traditional PMSM fan application, Hall detection circuit or reverse electromotive force detection circuit is commonly used to detect the initial state of the motor, but it also increases the hardware circuit control cost accordingly

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