The impact of switch mode regulated vibratory resonance conveyors with electromagnetic drive on the power supply network

Abstract

Vibratory resonance conveyors (VRC) having electromagnetic drives are often used to control the gravimetric flow of particulate materials. The realization of vibrations of variable intensity and frequency is achieved by means of a suitable power converter and the corresponding controller. Standard power stages intended for control of vibratory conveyance using SCR imply the use of phase angle control. Phase angle variation can only accomplish tuning the amplitude of oscillations of a VRC, but not their frequency. Also, it is generally known that SCR converters have a very negative influence on the power supply network. Application of switch mode power converters (SMPC) enables accomplishing the amplitude and/or frequency control of a VRC. The use of SMPC makes the excitation of a resonant VRC independent of the supply network frequency. The frequency control ensures operation of a VRC in the region of mechanical resonance. The resonance is the most efficient, because large output displacement is provided by small input power. Despite many advantages, switch mode regulated VRC having electromagnetic drive under certain conditions can have unfavourable influence on the network supply, especially if one takes into account the work of the resonant frequency which is close or equal to the network frequency.