High-voltage brushless DC motor sensing overload, stall and over-current predictive protection method

Abstract

The invention provides an intelligent sensing and overcurrent prediction and protection method for overload and locked-rotor of a high-voltage brushless DC motor. An intermediate soft starting moduleand a locked-rotor protection module are added to a work logic of a motor controller; and the controller can adjust a speed adjustment strategy and timely carry out protection in a locked-rotor faultof the motor. Intermediate soft starting is timely carried out by adopting the method and the duty ratio is gradually increased, so that the problem of long-term overcurrent of a drive circuit when the rotating speed is suddenly reduced is solved. The motor controller has an overcurrent prediction function, so that the overcurrent risk is avoided by the controller under the overcurrent predictionfunction in the locked-rotor and overload. The motor controller has locked-rotor protection, so that the controller can sense the external overload and locked-rotor degrees and carry out correspondingprotection operation. Therefore, the controller can avoid the overcurrent risk and can also sense the external load condition in the overload and locked-rotor, and the sensing capacity and the protective capability of the controller are improved.

Description

technical field [0001] The invention belongs to aviation electrical design technology, and relates to a high-voltage brushless DC motor's intelligent sensing and over-current prediction protection method for overload and locked-rotor. Background technique [0002] At present, the high-voltage brushless DC motor controller adopts such as figure 1 The control flow, PI control diagram such as figure 2 . The DSP uses the interrupt method to adjust the speed in a loop. Each time, it first calculates the required PWM wave duty cycle according to the current speed; Send the final duty ratio value to the PWM control register of DSP to obtain the PWM wave output of the required duty ratio to control the energy input of the motor to ensure that the motor maintains the rated speed under different loads. [0003] However, this control logic has a serious problem in actual use, that is, when the motor stalls, the duty cycle of the PI output will increase due to the large difference b...

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Problems solved by technology

[0003] However, this control logic has a serious problem in actual use, that is, when the motor stalls, due to the decrease in speed, the duty cycle of PI output will increase due to the large difference between the current speed and the target speed. The speed is low and the back EMF is small, so the high duty cycle and low speed will cause the forward current to increase

The lower the rotational speed is, the lower the counter electromotive force will be, resulting in excessive current passing through the motor controller, and in severe cases, it will cause the internal power drive circuit of the controller to burn out

[0004] Since the existing motor system can only provide the controller with three-phase Hall signals and the internal current and voltage signals of the controller, the controller cannot accurately perceive the specific conditions of the external load. Therefore, when the load is locked, the current design cannot accurately know degree of external jam

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