Dynamic Performance Comparison of a Moving Magnet Linear Compressor Under Symmetrical and Asymmetrical Voltage Waveforms

Linear compressors are commonly used in household appliances owing to their high efficiency. Previous studies on linear compressor dynamics neglected voltage waveform impact. In this paper, a moving magnet linear compressor is proposed and its numerical model incorporating stator assembly vibration is established. Dynamic properties of the linear compressor are compared in time and frequency domains driven by symmetrical and asymmetrical voltage waveforms. Simulation results show that the piston and stator assemblies exhibit a relative motion irrespective of waveforms. Under symmetrical voltage waveforms, greater oscillation amplitudes and velocities are exhibited, driven by the cosine waveform. The maximum compressor efficiency is achieved under the cosine waveform. Among asymmetrical voltage waveforms, the cosine waveform without troughs results in larger oscillation amplitudes. However, the maximum compressor efficiency is observed under the cosine waveform without crests. The maximum COP is achieved under the trapezoid waveform among all the symmetrical and asymmetrical waveforms. The smoother current curve is obtained driven by the voltage waveform with larger trough heights. Experimental results validate the analytical model.