Analog Digital Converter (ADC) triggering method and device during direct-current bus current detection through single resistor

Abstract

The invention discloses an ADC triggering method during direct-current bus current detection through a single resistor. The method comprises the steps of obtaining power module dead-band time, direct-current bus current signal rising stabilization time, ADC sampling maintaining time and minimum pulse width, and calculating minimum nonzero basic vector work time; determining whether nonzero basic vector work time is shorter than the minimum nonzero basic vector work time; correcting the Pulse Width Modulation (PWM) waveform if the basic vector work time is shorter, calculating effective nonzero vector work time according to the nonzero basic vector work time and the dead-band time of the corrected PWM waveform, and performing determination to obtain the ADC triggering moment to trigger ADC. By the aid of the method, the effective nonzero vector work time is determined to obtain the ADC triggering moment to trigger ADC sampling, and accordingly, the ADC sampling accuracy is improved. The invention further discloses an ADC triggering device during direct-current bus current detection through the single resistor.

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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