Air conditioner outdoor unit

Abstract

The invention discloses an air conditioner outdoor unit which comprises a three-phase motor, a frequency converter, a controller and a current sampling element. The three-phase motor is connected with the frequency converter; the current sampling element is connected to a direct current bus of the frequency converter; the current sampling element and the frequency converter are respectively connected with the controller; the controller is configured with an incomplete DPWM modulation mode, and the incomplete DPWM modulation mode comprises a first space vector modulation area and a same duty ratio modulation area; the first space vector modulation area accounts for 2/3 of a modulation wave period, and a space vector pulse width modulation strategy is adopted; the modulation area with the same duty ratio accounts for 1/3 of the period of the modulation wave, and a PWM wave modulation strategy with the same duty ratio is adopted, so that the wave crest voltage of the modulation wave is smaller than the positive voltage value of the direct current bus, and the wave trough voltage is larger than the negative voltage value of the direct current bus. When the three-phase motor runs at a low speed, the non-zero vector action time is prolonged by adopting an incomplete DPWM modulation mode, and the reliability of current sampling is improved.

Description

technical field [0001] The invention relates to the technical field of frequency conversion control, in particular to an air conditioner outdoor unit. Background technique [0002] The traditional Space Vector Pulse Width Modulation (SVPWM) is a continuous Space Vector Pulse Width Modulation (PWM), although the number of switching times of power switching devices is greatly reduced by reasonably arranging the action sequence of adjacent sector voltage vectors. However, there still exist the problems of many switching times of the power switching device and large loss of the switching tube. [0003] In order to reduce the switching loss of the space vector pulse width modulation (SVPWM) mode, the discontinuous space vector pulse width modulation (DPWM) mode has been widely concerned and applied. In DPWM modulation mode, the reference voltage of each phase bridge arm of the inverter is clamped to the positive or negative DC bus voltage in turn within 1 / 3 of the fundamental wa...

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problem of inaccurate sampling of the single current sampling element in the prior art when the three-phase motor is running at low speed, the present invention provides an outdoor unit of an air conditioner, which solves the problem of low-speed three-phase motor by using incomplete DPWM when the three-phase motor is running at low speed. When the non-zero vector action time is short, the current sampling is inaccurate, and the reliability of single current sampling is improved

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