Abstract

Bidirectional functionality in onboard chargers (OBCs) has emerged as a significant trend for electric vehicles (EV). This trend is enabling vehicle-to-everything (V2X) applications. Enhanced safety measures for vehicle-to-load (V2L) and vehicle-to-home (V2H) implementations are essential for protecting users from electrical shock hazards, which result from insulation failures. Consequently, insulation monitoring devices (IMDs) have become crucial components in bidirectional OBC systems. This document examines three prevalent IMD options for monitoring insulation: the basic architecture, dual-switch architecture, and active single-switch architecture—all options utilize electric bridge switch technology. This document thoroughly analyzes the advantages and limitations of each approach and presents comparative simulation results to evaluate the performance of each approach. Additionally, this document integrates theoretical analysis with specific device recommendations of Texas Instruments, offering a comprehensive reference guide for IMD circuit designs across various application scenarios.