Energy Efficiency of the Vibratory Device Electromagnetic Drive System

Abstract

Introduction. Vibration devices are widely used in industry for many processes, such as vibratory compaction of concrete mixtures, vibrational transportation, separation, etc. [7]. Among the known types of vibratory drives the most promising is an electromagnetic one, which has advantages, such as high reliability, long operating life, high energy efficiency when operating in near-resonance mode, easy control of vibration amplitude, the ability to generate vibrations at frequencies above 100 Hz [6]. The frequency and amplitude of the vibration device oscillations should firstly satisfy the requirements of the technological process and secondly, the vibration frequency should be close to the resonant one, to minimize energy consumption. Since the mechanical properties of the processed material can change over time, to support the near-resonant mode at a fixed vibration frequency, it is necessary to use elements with adjustable stiffness or mass, which significantly complicates the device design and increases its price. But in most cases the technological process allows to change the frequency of the forced oscillations in a certain range, which makes it possible to support the nearresonant mode by its regulation [3]. For example, to provide high quality of concrete products the vibration frequency during their processing should be in the range of 65 − 85 Hz [12]. In this case, it is expedient to choose the spring stiffness of the vibrator so that the device resonant frequency will be 75 Hz at a nominal mass of the product, and when changing the mass − to adjust vibration frequency tracking the changing frequency of the resonance within the predetermined frequency range. Thus it is possible to provide the vibration device work in the mode of the highest energy efficiency without having to change its mechanical properties.In many works, including [3,7], the authors approve, that the most energy-efficient mode takes place at the resonant frequency. This statement is based on the fact, that in the resonant mode to create a certain vibration amplitude the smallest amplitude of the electromagnetic force is required. But the calculations of the vibratory device electromagnetic drive system energy efficiency at different values of the oscillation frequency and the load are not made in any known work. Therefore, today it is not known what efficiency value can be achieved by configuring the system to resonance, and how it will change at the deviation of the vibration frequency from the resonant one. This information is needed for the synthesis of the control system.The aim of the work is to obtain the energy characteristics of vibratory device electromagnetic drive system at a variation of oscillation frequency and the load, as well as to determine the optimal frequency, providing the maximum efficiency.Equations of electromagnetic drive system energy losses. Energy efficiency of a drive system is defined as the product of the efficiencies of its constituent units: the converter, the motor and the gear [8]. There is no a g...

Control of Electromagnetic Vibratory Drive Using a Phase Difference Between Current Harmonics

“…The structure of subsystem Electromagnetic system of vibrator was described in [8,9]. It was supplemented with the unit for calculating the efficiency coefficient of a drive constructed based on equations from [3].…”

“…Currently due to their simplicity the devices with centrifugal drive are the most common [2]. Electromagnetic vibratory drive significantly surpasses centrifugal one in reliability, service life time, control capability, operating frequencies range and efficiency coefficient (when operating at nearresonant frequency) [1,3]. However its application field is considerably limited by complexity and high cost of automatic control system (ACS) which should provide stable vibrations in a near-resonant mode with a prescribed amplitude [4].…”

“…Investigations conducted in work [3] showed that with sinusoidal voltage supply to an electromagnetic vibrator winding through it there flows nonsine current whose spectrum has the first and the third harmonics. The presence of the third current harmonic is accounted for by the impact of electromotive force (EMF) induced in the winding due to change of air gap.…”

Resonant Modes of a Linear Permanent Magnet Vibratory Motor

“…To date, there is no clear idea in which mode (in terms of providing the necessary electromechanical performance) a vibrating machine with the permanent magnet motor drive should operate. It is considered generally acceptable to provide a mode close to mechanical resonance, since otherwise the drive efficiency is low [5][6][7]. It is also known that the frequency of phase mechanical resonance (hereinafter the phase mechanical resonance means the coincidence of the main harmonic components of electromagnetic force and mover speed) does not coincide with the frequency of maximum motor efficiency and maximum amplitudes of acceleration and displacement [8].…”

The System of Forming the Control Mode of the Electric Drive During the Start-Up of the Vibration Machine

“…To partially solve this problem, in practice, it is used the unregulated induction motor drive with 2-5 times high capacity of drive motors. This solution allows you quickly overcome the resonance zone, but leads to low energy performance compared to the electromagnetic drive of vibration device [7]. In this regard, a number of ways have been developed to reduce the amplitude of oscillations of VM actuating device during passing the resonance zone both by upgrading the mechanical part of VM and with the help of electric drive systems.…”