Experienced Power Electronics Engineer Needed for 3–5 kW Residential Hybrid Solar Inverter — Complete Design Files

I am looking for an experienced power electronics engineer or engineering team to design a residential-scale hybrid solar inverter for commercial production.

The project involves developing a single-phase, 230 V AC, 50 Hz pure sine-wave hybrid inverter that integrates rooftop solar panels, a lithium battery bank and the utility grid. The design should prioritise high efficiency, reliability, safety and ease of manufacturing.

I prefer an engineer with previous experience designing working solar inverters, grid-connected converters, MPPT controllers and bidirectional battery systems. An existing, validated reference design that can be licensed or transferred is preferred.

1. Target Specifications

Rated power: 1–5 kW continuous

AC output: 230 V RMS, single phase, 50 Hz

Output waveform: Pure sine wave

Battery systems: 12 V, 24 V and upto 96 V variants, subject to practical power limitations

Battery chemistry: LiFePO4 and other supported lithium chemistries

Solar input: Photovoltaic array with MPPT

Grid operation: Grid synchronisation and controlled power export

Operating modes: Solar self-consumption, battery charging/discharging, grid import/export and backup operation

Monitoring: Wi-Fi and/or RS-485, preferably Modbus RTU

Control: DSP or microcontroller-based digital control

Design priorities: High efficiency, thermal performance, protection and cost-effective manufacturing

The engineer should recommend a suitable power-stage topology, explaining the trade-offs in efficiency, isolation, complexity, component cost and manufacturability.

2. Required Engineering Deliverables

A. Circuit Design and Documentation

Complete functional block diagram

Full circuit schematics

Editable native schematic files

Power-stage calculations and component-selection rationale

DC-link, gate-driver and protection circuit designs

Solar MPPT and battery charging circuitry

Grid-interface and output-filter design

Thermal management and component derating documentation

B. PCB Design and Manufacturing Files

Editable native PCB layout files

Gerber and drill files

PCB fabrication and assembly drawings

Component footprints and libraries

Complete BOM with manufacturer part numbers

Suggested component suppliers and alternative parts

Connector, wiring and assembly documentation

Preferred EDA tools include Altium Designer, KiCad, OrCAD or an equivalent professional platform.

C. Firmware and Control Software

Provide complete firmware source code or an agreed, sufficiently detailed control implementation.

Required functions include:

Grid voltage and frequency synchronisation

Digital inverter control and current regulation

Solar MPPT algorithm

Lithium battery charging and discharging control

Grid import/export power control

Self-consumption prioritisation

Programmable export limits

Scheduled battery charging based on time-of-use tariffs

Fault detection, logging and safe shutdown

Monitoring and communication interfaces

Deliver the source code, build instructions, required libraries, configuration settings and programming documentation.

D. Grid Interaction and Protection

The design must address:

Anti-islanding protection

Grid overvoltage and undervoltage protection

Grid overfrequency and underfrequency protection

Overcurrent and short-circuit protection

Battery overvoltage, undervoltage and overcurrent protection

Overtemperature protection

Appropriate grounding, isolation, creepage and clearance

DC injection and residual-current considerations

Safe transitions between grid-connected and backup operation

Export limiting using suitable metering or current sensing

The engineer must identify the applicable Indian grid-interconnection and product-safety standards. IEEE 1547 or equivalent requirements should be considered where relevant.

Certification must not be claimed unless the applicable testing and approval processes have been completed.

E. Monitoring and Communication

Provide a basic monitoring interface or documented communication implementation supporting Wi-Fi and/or RS-485.

Monitor at least:

Solar voltage, current and power

Battery voltage, current, state of charge and status

AC voltage, current, frequency and power

Grid import/export power

Operating mode and power limits

Temperature, alarms and fault codes

Energy-generation and consumption data

Modbus RTU over RS-485 is preferred where appropriate.

F. Simulation and Test Plan

Provide simulation files and results where applicable, along with a documented validation plan covering:

Conversion efficiency and power losses

MPPT operation

Battery charging and discharging

Load-step and transient response

Overload and short-circuit protection

Thermal performance

Grid synchronisation and export control

Anti-islanding validation

Monitoring and communication

Prototype commissioning and troubleshooting

Clearly distinguish simulated results, estimated performance and measurements from a physical prototype.

3. Preferred Qualifications

Applicants should have demonstrable experience in:

1–5 kW solar or hybrid inverter design

Grid-connected power electronics

SPWM, current-mode control and digital control loops

MPPT and bidirectional DC/DC converters

Lithium battery charging systems

DSP/MCU firmware development

Power MOSFET, SiC or GaN device selection

Gate drivers, EMI/EMC and thermal design

High-current and high-voltage PCB design

Prototype testing and troubleshooting

Experience with dsPIC, STM32, TI C2000 or comparable controllers is preferred.

Please specify the tools you use, such as Altium, KiCad, MATLAB/Simulink, PLECS, LTspice or PSpice.