MC PCDU

Status

Ongoing
Status date

2025-06-09
Activity Code

4F.168

Objectives

The project aims to develop modular power conditioning units for solar array sections using a switching regulator. This approach ensures precise power regulation while integrating a Battery Charge Control and Monitoring System based on a battery follower architecture. The main goals are:

Battery current control: which dynamically adjusts charge current and voltage limits.
Solar Array integration: the number of SA sections connected to the main bus are based on power demand and system constraints.
Deliverable outcome: an engineering qualification model of a market-driven PCDU, optimized for cost, mass, volume, and efficiency, while maintaining compatibility with existing Airbus Crisa PCDUs.

Challenges

The key technical challenge is adapting battery level control and solar array power regulation functions to Commercial Off-The-Shelf (COTS) components while preserving the performance, reliability, and integration of heritage designs. Additionally:

Both designs must fit within the existing mechanical design of previously developed Printed Circuit Boards (PCBs).
The controller architecture must ensure a seamless adaptation of the SA power regulation stage, including regulation and switch control via the Main Error Amplifier in the battery module.
The control system must allow programmable battery charge current and voltage limits via the CTRL module.

Benefits

Controller Area Network (CAN) bus interface: Adopting this widely used standard ensures compatibility with most low Earth orbit (LEO) constellation market interface requirements.
Enhanced bus quality: Direct battery control at the Modular to Constellations Power Control and Distribution Unit (MC PCDU) level reduces ripple and transients.
Unregulated bus design: Optimised for mass and volume savings, enabling efficient charge/discharge regulation for the battery interface.
Fully industrialised design: Competitive unit pricing reduces overall subsystem costs, making it a cost-effective power solution for large satellite constellations.

Features

The Modular to Constellations Power Control and Distribution Unit (MC PCDU) delivers up to 4 kW @ 28V with 98% efficiency in a modular and scalable configuration, enabling adaptable power distribution. It features an unregulated main power bus, Linac Coherent Light Sources (LCLs) for precise power management, stepper motor drivers, and fuses for circuit protection. Integrated CAN Bus communication ensures conventional system integration, while its compact, high-efficiency design optimises mass and volume.

System Architecture

This project is limited to the development of battery module to provide battery charge control and monitoring, the development of a conditioning module to condition the solar array sections by a switching regulator. The Telemetry and Telecommand (TM/TC) management is implemented via CAN serial bus is implemented.

Plan

The project aims to develop an Engineering Quality Model (TRL7) with a distributed design across three phases:

Architecture and Preliminary Design Phase (RR to PDR): Verify feasibility of design;
Detailed Design Phase (PDR to CDR): Unit characterisation. Design approval;
Validation Phase (CDR to QR): Unit Qualification.

Current status

Requirement Review is planned on June 2025.