Konstantinos Xyderos

Eunice Energy Group

Firmware engineer — HEDNO/FoSE gateway

Context

Greek law requires renewable and cogeneration stations above 400 kW to be equipped so the distribution operator, HEDNO, can supervise them and curtail or disconnect them when network stability demands it. HEDNO publishes the specification for that equipment, and a station cannot connect to the network until the interface has been tested and certified. I am building Eunice's implementation from scratch: an industrial Kunbus RevPi in the station's control cabinet, backed by a UPS, acting at once as a protocol mediator between the operator and the plant, and as the control application that applies the operator's commands to real power electronics.

Responsibilities

• Own the architecture and implementation of the controller against HEDNO's published specification.
• Serve as the IEC 60870-5-104 server that the operator's SCADA commands and interrogates.
• Read plant output and write active-power setpoints to the inverters over Modbus TCP.
• Read measurements and protection signals from the station's IEC-61850 relay over MMS.
• Write setpoints through an OPC XML-DA park controller as an alternate path.
• Actuate and sense the breaker, earth switch and relays over digital I/O.
• Implement the RfG grid-code behaviours: LFSM-O, FSM and LFSM-U.
• Define precedence between the operator, the aggregator and the local producer.
• Hold the plant on its last settings and cycle the router when the SCADA link drops.
• Mirror telemetry to a cloud broker over mutual TLS.
• Own cyber-security across both command origins, and the packaging and provisioning of the device for field deployment.

Achievements

• Consolidated five downstream plant interfaces behind a single regulated upstream one, so equipment can change without altering the HEDNO-facing contract.
• Designed the station to stay predictable through a lost SCADA link rather than only through the normal case.
• Treated the cloud command downlink as a control-plane path, since it can reach the same inverter setpoints the operator commands.
• Formal HEDNO conformance testing is the gating commissioning activity ahead.

Technologies

• C
• Python
• IEC 60870-5-104
• IEC 61850
• Modbus
• OPC XML-DA
• MQTT
• Kunbus RevPi
• Debian
• aarch64
• Bash
• Git

Polarium

Firmware engineer

Context

Polarium Home is a residential battery energy storage system. The product has to coordinate a battery, an inverter and the grid safely and continuously in an unattended domestic installation.

Responsibilities

• Own the control and communication module coordinating battery and inverter.
• Built a Yocto-based controller for a proof-of-concept system coordinator.
• Integrated a new inverter supporting PV and grid services.
• Developed Battery Management System functionality, including pre-charge.
• Work with product and project managers on requirements definition and risk assessment.

Achievements

• Delivered a working proof-of-concept system coordinator on Yocto.
• Brought a new inverter into the product, extending it to PV and grid services.
• Implemented BMS pre-charge, a prerequisite for safe energisation of the system.

Technologies

• C
• Go
• Python
• Yocto
• Compute Module 4
• ESP32-S3
• Modbus
• MQTT
• Protocol Buffers
• Git

Getinge

Team / tech lead

Context

Regression testing for a ventilator platform was largely manual, which made it slow and therefore infrequent. The assignment was to replace it with an automated framework covering both the hardware rig and the software driving it.

Responsibilities

• Led the software team building the automated testing and regression framework.
• Defined the architecture and implemented the core components, hardware and software alike.
• Worked with the cyber-security team to build their requirements into the test mechanisms and the firmware update flow.
• Coordinated between the team and the ventilator department that owned the product under test, including agreement on acceptance criteria.
• Reduced regression testing time by approximately 45% through full automation.

Achievements

• Reduced regression testing time by approximately 45% through full automation.
• Built cyber-security requirements into the framework from the start rather than retrofitting them onto a finished system.
• Established acceptance criteria agreed jointly with the department owning the product under test.

Technologies

• C++
• Python
• Linux
• Bash
• Linux networking
• GitLab
• Git

Wittra

Firmware engineer

Context

Wittra runs a low-power mesh network of tracking tags coordinated by gateways from the cloud. Airtime and battery life are the limiting resources, so protocol overhead has a direct cost across every device in the field.

Responsibilities

• Developed on a Yocto-based distribution coordinating the network system from the cloud.
• Routed data, capabilities and configuration to cloud and on-premises endpoints over MQTT and gRPC.
• Built remote software update and the positioning engine within the network mesh.
• Implemented a 16-bit addressing scheme for connected devices, reducing payload by approximately 25%.
• Mentored a summer intern through OTA firmware update work for both gateway and tags.

Achievements

• Reduced payload by approximately 25% across the mesh through the 16-bit addressing scheme.
• Took a summer intern to independent work on OTA firmware updates for gateway and tags.

Technologies

• C
• Go
• Python
• Yocto
• Compute Module 4
• STM32
• MQTT
• gRPC
• Protocol Buffers
• MIOTY
• 6LoWPAN
• Bluetooth LE
• Git

Eunice Energy Group

Firmware engineer — inverter data gateway

Context

A gateway for harvesting operational data from inverters across a photovoltaic installation and issuing commands back to them. Taken from initial concept and requirements through to the production line.

Responsibilities

• Conceptualised the gateway and carried it from design and requirements to production.
• Developed on a Linux distribution coordinating metrics and commands across inverters.
• Implemented the services handling network configuration and inverter communication.
• Built cloud data routing and a request–response scheme for executing commands on inverters.
• Built the internal tooling, inverter simulators and the hardware-in-the-loop test platform.

Achievements

• Carried the gateway from concept through to the production line.
• Built a hardware-in-the-loop platform and inverter simulators, allowing firmware to be exercised against realistic behaviour without occupying physical hardware.

Technologies

• C#
• .NET
• Python
• Compute Module 4
• Modbus
• MQTT
• Protocol Buffers
• Redis
• Linux
• Docker
• Git