Two-Level Excitation Current Driver to Reduce the Driving Power of an Electromagnetic Contactor

Abstract

As the capacity of the electrical system increases, so does the capacity of the electromagnetic contactor (MC). This increases the burden on the MC drive, which consumes unnecessary power in the system. MC is characterized by different initial starting-operating currents and holding currents to maintain contact. However, the operating voltage is constant regardless of the operating state. The initial starting current is considerably larger than that required to maintain contact. However, once the electromagnetic contactor is in the closed state, the current to maintain the contact is relatively small compared to the initial starting operating currents. Therefore, this study proposes two types of two-level excitation-current type MC drives that can reduce the drive power by employing features that have different conditions depending on the operating state of the MC. The overall drive power is reduced by applying different excitation currents based on the operating state. The controller and system proposed in this study were simulated using Powersim 9.1 (PSIM), and the feasibility was verified by manufacturing an analog-type driver using LM2576 and a digital-type driver using an MCU. The simulation and experimental results provide significant data for verifying the high performance and reliability of the proposed controller and system.

Keywords

• electromagnetic contactor (MC)
• flux density
• excitation current
• analog-type driver
• digital-type driver