A Resonant Frequency Tracking Control Method of Linear Compressor

Abstract

The invention relates to the technical field of linear compressor control, in particular to a resonance frequency tracking control method for a linear compressor. According to the method, a current instantaneous value i of a stator current signal and a current instantaneous value x of a rotor displacement signal are detected separately; the stator current signal i and the rotor displacement signalx are accessed into a multiplier to obtain a product i.x of the stator current signal i and the rotor displacement signal x; an error signal as shown in the specification is acquired through a low-pass filter; the power supply frequency is adjusted through a PI adjuster by using the error signal, that is to say, the modulation frequency of motor-powered SPWM is adjusted until the steady-state error signal as shown in the specification is zero; and meanwhile, the power supply frequency of the linear compressor is equal to the resonance frequency of the linear compressor and the linear compressor works in a resonance state. By adopting the low-pass filter and the PI adjuster, the resonance frequency of the linear compressor can be effectively and quickly tracked, and the system efficiency of the linear compressor during variable load operation is improved.

Description

technical field [0001] The invention relates to the technical field of linear compressor control, in particular to a resonant frequency tracking control method of a linear compressor. Background technique [0002] The linear compressor is a new type of compressor directly driven by a linear oscillating motor. Compared with the traditional piston compressor, it can save the intermediate conversion mechanism such as the crank connecting rod that converts the rotary motion into the linear reciprocating motion, and has a compact structure. , high transmission efficiency and easy control. At present, it has been widely used in regenerative cryogenic systems such as thermoacoustic, pulse tube and Stirling. The linear compressor can be equivalent to a typical second-order spring oscillation system. When the electrical drive frequency of the linear oscillating motor is the same as the resonant frequency of the linear compressor system, the system is in a state of resonance at this ...

AI Technical Summary

Problems solved by technology

Since the phase detection of the current and position signals requires at least half an electrical cycle T / 2 (T=2π / ω), that is, the power supply frequency is adjusted every T / 2 time, which will cause the tracking response of the resonant frequency tracking control to slow down

In addition, a Chinese invention patent with application number 201610842155.9 discloses a resonant frequency tracking control method for linear oscillating motors. This method requires a second-order generalized integrator and coordinate transformation, and the calculation is complicated.

It can be seen that the existing linear compressor resonant frequency tracking control method has problems such as slow response, complex calculation and poor anti-interference ability.

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