A method and system for suppressing low-frequency vibration of a compressor

Abstract

The invention provides a method for suppressing low-frequency vibration of a compressor and a system for suppressing low-frequency vibration of the compressor. Different from a moment control method for compensation aiming at loading moment in the prior art, the method based on pulsating loading moment includes the steps of controlling motor moment to a leading phase by means of presetting, and then computing leading phase determination of the motor moment by means of phase detection of velocity pulsation components and computing current commands for reducing vibration by means of velocity pulsation, so that real-time phase moment compensation is performed for the motor moment by means of the leading phase determination, and the current commands have a great effect on vibration suppression, particularly vibration suppression in low-speed operation. By the aid of the leading phase moment compensation technology of low frequencies of the variable-frequency compressor, vibration and pipe stress of the low-frequency compressor are reduced, and a null displacement state of a pipeline is achieved when the compressor is in ultralow-frequency operation, so that the refrigerating capacity of an air conditioner is expanded to a low-capacity side, and energy-saving and comfortable effects of variable frequencies are achieved.

Description

technical field [0001] The present invention relates to a method and a system for suppressing vibration of a compressor, and more specifically, relates to a method and a system for suppressing low-frequency vibration of a DC frequency conversion compressor. Background technique [0002] With the advent of the worldwide energy crisis, traditional air conditioners will gradually withdraw from the market due to their low operating efficiency. As a new technology with outstanding energy-saving effects, inverter air conditioners are an inevitable trend in the development of the air-conditioning industry. However, for DC inverter air conditioner compressors, especially for single-rotor compressors, there will be a prominent problem of load imbalance during low-frequency operation. In order to prevent the overall vibration of the DC inverter air conditioner compressor due to the vibration of the compressor, the air conditioner is loosely fixed to the chassis through an elastic sup...

AI Technical Summary

Problems solved by technology

If the piping is allowed to vibrate, in the worst case, due to vibration stress fatigue, the piping may break.

[0005] 2. Moreover, due to low-frequency vibration, low-speed operation cannot be performed, the cooling capacity of the air conditioner cannot be expanded to the low-capacity side, and the power consumption of repeated switch control increases, and the inverter compressor cannot operate at a wide frequency.

[0017] (1) Under normal circumstances, the change of the motor output torque always lags behind the load of the compressor, so the control will lag behind the actual, so that the torque will be compensated when the load changes from heavy to light, such as Figure 4 As shown, the variable torque control waveform will have a significant difference in size within one cycle; if the motor torque is determined by combining the load ripple ΔτL according to the torque control, it may exceed the allowable current of the inverter and cannot run. Then, set the current command to In the current-limited state, the motor torque cannot be combined with the load torque, and the feedback control system cannot be established. The phase delay of the motor torque compared with the pulsating load torque also increases the vibration of the compressor compared to when torque control is not performed. , which leads to the imbalance between the output torque of the motor and the load torque of the compressor, and finally makes the compressor experience two states of acceleration and deceleration during one revolution, and the vibration increases instead, such as Figure 5 As shown, when the speed pulsation becomes the smallest, the vibration of the compressor is not necessarily the smallest

[0018] (2) Motor loss increases due to motor current pulsation

Images