Case Study: Variable-Voltage DC Bus With Energy Recovery System for Industrial Plants

Andre Dos Santos Lima,Fernando Luiz Marcelo Antunes,Aderaldo Ricarte Guedes,Edilson Mineiro Sa

doi:10.1109/access.2021.3095754

Andre Dos Santos Lima, Fernando Luiz Marcelo Antunes + Show 2 more

Open Access

https://doi.org/10.1109/access.2021.3095754

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Abstract

Direct current (DC) buses and microgrids have drawn significant attention owing to the simple integration of distinct sources and energy storage systems. However, most research efforts refer to the use of DC buses for residential, datacenter, and telecommunications applications rather than manufacturing industry, where processes are controlled by alternating current (AC) motor drivers. This work proposes a novel approach of a DC bus used as primary power supply in manufacturing industrial plants for replacing the traditional AC bus. Unlike most applications, the DC bus voltage presents a variable magnitude and allows energy recovery aiming to improve energy efficiency. This arrangement employs a capacitor bank directly to the DC bus, which is responsible for storing the energy that, otherwise, would be lost during the motor braking. Simulation in PSIM software and experimental results on an industrial plant involving a real polyvinyl chloride (PVC) injection machine supplied directly by the DC bus, in which the voltage varies between 535 V and 600 V, are presented and discussed to validate the proposed approach. The obtained results show that the DC bus does not require a rigid control of the voltage magnitude, thus allowing a reduction of up to 5.05% in energy consumption.

Highlights

Since the late 19th century, distinct studies focused on the improvement of efficiency regarding alternating current (AC) transmission and distribution systems have been discussed in the literature and industry
AC systems became more popular than direct current (DC) ones due to the inherent simplicity to adapt distinct voltage levels associated with the use of transformers and consequent reduced cost
The growth in the use of electronics, and more and more equipment supplied by DC power, significant research effort has been dedicated to the development of DC buss in small-size networks to supply high-power loads and minimize losses [7]

Summary

INTRODUCTION

Since the late 19th century, distinct studies focused on the improvement of efficiency regarding alternating current (AC) transmission and distribution systems have been discussed in the literature and industry. EMerge Alliance, which is an open industry association of energy and telecommunication equipment manufacturers, was created to promote research and development of standards focused on energy efficiency in the context of data center equipment and residential applications where DC bus are employed. Since 2004, when the Berkeley National Lab has launched the work on DC bus for buildings, researchers have focused on a fixed voltage bus with different level for specified applications as seen in [34]–[36]. The effectiveness of the proposed system with variable voltage DC bus is validated through simulation and experimental results in a real shoes industrial plant

DC BUS USED IN INDUSTRIAL MOTOR DRIVES APPLICATIONS

SIMULATION OF ENERGY CHANGES BETWEEN MOTORS AND DC BUS

EXPERIMENT PERFORMED ON FACTORY

ENERGY RECOVERY SYSTEM

Findings

CONCLUSION