EV Powertrain Controller Thermal Design

Project Title: Thermal Simulation and Heatsink Design for a 72 V EV Powertrain Controller – 15 kW Rated, 25 kW Peak We are developing an electric-vehicle powertrain controller and are looking for an experienced freelancer to undertake semiconductor loss estimation, thermal simulation, cooling-system selection and manufacture-ready heatsink design. The assignment must include complete editable calculation files, simulation models, mechanical CAD files and manufacturing drawings so that our team can manufacture the cooling system and modify the design independently. PROJECT SPECIFICATIONS * Nominal DC input voltage: 72 V/108V * Continuous rated power: 15 kW * Peak power: 25 kW * Application: EV traction motor controller * Power semiconductor: To be selected through analysis, with low-voltage silicon MOSFETs as the initial candidate. * Cooling method: To be selected after evaluating passive, forced-air and liquid cooling. The battery voltage range, motor phase-current limits, switching frequency, peak-power duration, operating temperature and packaging constraints will be finalised before detailed simulation. The basis of the power ratings—DC input, inverter electrical output or motor shaft output—will also be confirmed. SCOPE OF WORK 1. Requirements Review and Semiconductor Selection * Review the available controller, motor and mechanical specifications. * Provide an input checklist and identify missing information. * Document assumptions for our approval before proceeding. * Evaluate MOSFET versus IGBT suitability using actual device characteristics. * Compare at least two suitable MOSFET options. * Recommend device part numbers, voltage rating, package type and number of parallel devices. * Consider maximum battery voltage, switching overshoot, current capability, losses, thermal performance and mounting requirements. 2. Electrical Power-Loss Estimation Calculate component-level losses under the agreed operating conditions, including: * Semiconductor conduction and switching losses. * Dead-time/freewheeling and reverse-recovery losses. * Temperature-dependent losses and unequal current sharing between parallel devices. * DC-link capacitor losses. * PCB, busbar, shunt and connection losses. * Other significant heat sources within the controller. Provide editable calculations and a component-wise heat-source map. The calculations must use the proposed circuit, device data and operating conditions rather than relying only on an assumed overall efficiency. 3. Thermal Simulation Develop steady-state and transient thermal models covering: * Continuous operation at 15 kW until thermal equilibrium. * Peak operation at 25 kW for the agreed duration. * Repeated peak operation, including peaks starting from an already-hot controller. * Low-speed, high-torque operation. * Relevant high-speed and regenerative-braking conditions. * Worst-case battery voltage and switching-frequency conditions. * Maximum specified ambient or coolant temperature. * Reduced cooling or cooling failure, with recommended derating and shutdown behaviour. The model must include semiconductor thermal paths, PCB/baseplate, thermal-interface materials, contact resistance, enclosure and relevant airflow or coolant conditions. Report estimated semiconductor junction temperatures, component temperatures, heatsink temperatures and identified hot spots. Use temperature-dependent losses consistently with the predicted operating temperatures. 4. Cooling-System and Mechanical Design * Compare passive, forced-air and liquid cooling based on thermal performance, dimensions, weight, complexity and manufacturability. * Develop the selected cooling solution in detail. * Optimise heatsink/baseplate dimensions, fin geometry, component placement and thermal interfaces. * For forced-air cooling, specify the fan/blower and its operating point considering system pressure drop. * For liquid cooling, specify cold-plate geometry, coolant type, inlet temperature, flow requirement and pressure drop. Clearly identify whether external pump and radiator sizing are included. * Recommend temperature-sensor locations and thermal operating limits. * Review the proposed design for manufacture using the agreed fabrication process. INPUTS PROVIDED BY OUR TEAM We will provide available: * Motor and controller specifications. * Electrical schematics and candidate component datasheets. * PCB layout, layer stack-up and copper details. * Mechanical dimensions and enclosure constraints. * Operating conditions and duty-cycle requirements. * Cooling resources and installation details. * Manufacturing preferences and prototype-testing arrangements. As this is a development project, some inputs may not be finalised at the start. The freelancer must identify these gaps and propose the information or calculations required. All assumptions must be documented and approved. Final simulation must use the agreed design geometry. MANDATORY DELIVERABLES 1. Design-basis document containing specifications, operating cases, assumptions and acceptance criteria. 2. Semiconductor selection report containing device comparisons, recommended part numbers and parallel-device configuration. 3. Editable electrical-loss calculations, including spreadsheets, scripts or simulation models and supporting device data. 4. Complete native thermal simulation projects, including geometry, material properties, thermal contacts, heat sources, boundary conditions, mesh, solver settings and all required dependencies. 5. Thermal simulation report containing junction and component temperatures, hot spots, transient curves, cooling performance, energy-balance checks, convergence and mesh-sensitivity results. 6. Native editable mechanical CAD parts and assemblies, together with STEP exports. 7. Manufacture-ready drawings containing: • Overall dimensions and material grades. • Base thickness and fin dimensions. • Device mounting positions. • Hole locations, threads and depths. • Dimensional tolerances. • Contact-surface flatness and finish. • Surface-treatment requirements. • Assembly and exploded views. 8. Cooling-system bill of materials identifying thermal pads/grease, electrical insulation, fans/pumps, fittings and fasteners, as applicable. 9. Assembly instructions covering surface preparation, thermal-interface thickness, mounting sequence, clamping and fastening requirements. 10. Thermal operating recommendations, including sensor locations, continuous/peak limits and proposed derating/shutdown thresholds. 11. Prototype validation plan covering instrumentation, sensor locations, operating conditions, test sequence and comparison of measured and simulated temperatures. 12. Final handover session demonstrating how to open the files, modify inputs, rerun the simulation and export results. For a liquid cold plate, the drawings must also specify coolant channels, ports, seals, joining methods, working pressure and proposed leak/proof-testing requirements. Screenshots, PDF reports or STEP files alone will not be accepted as the complete design handover. All native editable source files must be supplied. ACCEPTANCE AND REVISIONS * Component temperatures must remain within agreed design limits, with documented margins to datasheet limits. * The design must support 15 kW continuous operation and 25 kW peak operation for the agreed duration and repetition rate. * Cooling performance must be evaluated under the specified installation conditions. * Manufacturing drawings must be suitable for fabrication by our selected vendor. * Include two design-review revisions in the base quotation. * Quote separately for one prototype-test correlation and subsequent model/design update. * Clearly state responsibilities for prototype fabrication, component procurement and physical testing. * Software versions, licence requirements and third-party model restrictions must be disclosed before award. All project-specific files must be handed over with rights for our team to modify the design, manufacture it and share the necessary files with our fabricators. REQUIRED EXPERIENCE The freelancer should have experience in power-electronics loss calculation, motor-drive thermal analysis, CFD/FEA and practical heatsink or cold-plate design. Please share examples of relevant completed projects and identify the proposed software. If electrical-loss modelling requires a separate specialist, disclose this in the proposal. PLEASE INCLUDE IN YOUR PROPOSAL * Relevant experience and sample deliverables. * Proposed methodology and input requirements. * Software and licence requirements. * Estimated timeline and milestone-wise quotation. * Included revisions, assumptions and exclusions. * Separate cost for prototype-test correlation. * Confirmation of complete editable simulation, CAD and manufacturing-drawing handover.

Project ID: 40740323