INTRODUCTION

This guide provides integration support for connecting the AES CAB BMS (the SBAU controller) to your Energy Management System (EMS) software. It facilitates the communication and control needed for deploying localized PCS and EMS coordination in large-scale BESS systems.

The guide serves as a technical bridge between the AES high-voltage BESS hardware and third-party or custom-built EMS solutions.

For AES CAB Systems utilizing the Battery Array Unit (BAU), the BAU functions as the centralized controller for the high-voltage battery management system (BMS). It plays a critical role in orchestrating and aggregating data, controls, and safety functions across the distributed Battery Cluster Control Units (BCUs) that make up the system.

The BAU performs both stack-level management and external interface functions, ensuring that the entire battery array operates safely, efficiently, and in coordination with upstream systems such as Energy Management Systems (EMS), Microgrid Controllers (MGC), or Power Conversion Systems (PCS).

Core Functions of the BAU

• System-wide Command Execution
  The BAU receives commands from upstream controllers (EMS/MGC) and executes actions across all clusters, such as power-on/off sequencing, remote fault clearing, and synchronized parameter updates.

• Cluster Coordination and Protection Logic
  The BAU consolidates operational and protection data from each cluster, evaluates stack-wide conditions (e.g., voltage imbalance, overcurrent, insulation fault), and issues coordinated actions such as relay open/close, charging/discharging inhibition, or precharge initiation.

• Relay and Balancing Management
  Through a combination of Modbus and CAN-based communication, the BAU manages relay control and cabinet operations. Ensuring electrical balance throughout the stack.

• Gateway Communication Interface
  The BAU acts as the Modbus TCP/IP and/or CAN interface point for upper-level systems, aggregating cluster-level data into a unified register map and supporting system-level monitoring, diagnostics, and control from an EMS or MGC.

Communication Interfaces:

• To SBCUs: Over CANbus, with support for real-time fault, status, and telemetry exchange.

• To EMS/MGC: Via Modbus TCP/IP, providing access to stack-level metrics, relay statuses, fault flags, alarm thresholds, and time-synchronized operating parameters.

Application Relevance

The BAU architecture is ideal for modular and scalable high-voltage energy storage systems, particularly where multiple battery clusters must be coordinated as a unified whole. Whether in grid-tied C&I systems, off-grid microgrids, or hybrid renewable plants, the BAU enables seamless PCS and EMS integration and centralized system control.