Method and device for triggering adc when detecting dc bus current through a single resistor

Abstract

The invention discloses a method for triggering an ADC when detecting a DC bus current through a single resistance, comprising the following steps: obtaining the dead time of a power module, the rising and stabilizing time of a DC bus current signal, ADC sampling and holding time and the minimum pulse width, and calculating the minimum Non-zero basic vector working time; judge whether the non-zero basic vector working time is less than the minimum non-zero basic vector working time; if yes, correct the PWM waveform; according to the non-zero basic vector working time and dead time of the corrected PWM waveform Calculate the effective non-zero vector working time, and judge it to obtain the trigger moment of the ADC to trigger the ADC. In the triggering method, the ADC sampling is triggered by judging the effective non-zero vector working time to obtain the triggering moment of the ADC, thereby improving the accuracy of the ADC sampling. The invention also discloses an ADC trigger device when detecting the DC bus current through a single resistance.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method for triggering an ADC when detecting a DC bus current through a single resistor and a trigger device for an ADC when detecting a DC bus current through a single resistor. Background technique [0002] With the continuous development of home appliances such as air conditioners, it is necessary to continuously reduce their production costs to meet market demand. In home appliances such as air conditioners, the drive motor and its control circuit have a greater impact on production costs. [0003] Among them, the technology of detecting the DC bus current through a single resistor has been developed rapidly because of its high cost performance. When the DC bus current is detected through a single resistor, only one sampling resistor can be used to detect the DC bus current, and the detected DC bus current can be re- The three-phase phase current of the motor is cons...

AI Technical Summary

Problems solved by technology

At the same time, in order to reduce switching losses, it is also necessary to limit the minimum pulse width of the PWM waveform, and this minimum pulse width limit is also affected by the rise and stabilization time of the DC bus current signal and the ADC sampling and holding time.

The combined effect of these constraints makes the ADC triggering of the technique of detecting the DC bus current with a single resistor extremely complicated, and the existing technology generally triggers ADC sampling at the midpoint of the non-zero basic vector working time. This rough ADC trigger setting There is the problem of inaccurate DC bus current detection

[0005] In addition, a related technology proposes a circuit for improving motor phase current reconstruction through the DC link. Although considering the long ADC conversion time, the two ADC conversion processes are separated, and the analog-to-digital conversion is performed uniformly in the zero-vector interval. This complicates the ADC processing

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