Low-cost quick reconstruction method for phase current of permanent magnet motor of fan

Abstract

The invention discloses a low-cost reconstruction method for phase current of a permanent magnet motor of a fan. The low-cost reconstruction method includes that in a Space Vector Pulse Width Modulation (SVPWM) control process for the permanent magnet motor, when the rotational speed of the motor is higher than a rated rotational speed by 5%, a reference voltage vector is prevented from being in a low-modulation area; when the reference voltage vector is in an unobservable area, the position of a voltage vector process and obtained by a microcontroller of the motor when the microcontroller of the motor is withdrawn from an effective solvable area at a previous moment replaces the position of the reference voltage vector which is just in the unobservable area, and the magnitude of the current reference voltage vector keeps unchanged so as to solve problems caused by insufficient action time of each nonzero basic voltage space vector when an existing reference voltage vector is in a low-modulation area and an unobservable area; and the reference voltage vector in the low-modulation area or the unobservable area is switched into the effective solvable area, so that the phase current of the motor is reconstructed by a single-resistance sampling bus direct-current process. The low-cost reconstruction method has the advantages of simplicity, practicality, high reconstruction speed and suitability for meeting application requirements of low-cost household electrical appliance products.

Description

technical field [0001] The method of the invention is applied in the field of permanent magnet motor control, and in particular relates to the fan permanent magnet motor control technology under the Space Vector Pulse Width Modulation (SVPWM) method. Background technique [0002] In the permanent magnet motor control system, the commonly used permanent magnet motor current sampling methods mainly include: 1) using two current Hall sensors to sample the two-phase phase current of the motor; 2) using a single Hall sensor to sample the positive and negative DC bus currents Perform current reconstruction. These two methods have the advantages of simple use and electrical isolation, but they are expensive and bulky. Therefore, the method of using a single resistor to sample the DC bus current to reconstruct the phase current of the permanent magnet motor has a good price advantage and application prospect for some price-sensitive civil motor speed control products. [0003] Und...

AI Technical Summary

Problems solved by technology

However, the realization of the PWM wave phase shifting method has high requirements on the motor microcontroller, the algorithm is complex to implement, and the cost is high, which is not suitable for the application requirements of low-cost civilian products (such as electric fans).

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