ISO 21782-4:2021

Overview

ISO 21782-4:2021 - Electrically propelled road vehicles - Test specification for electric propulsion components - Part 4: Performance testing of the DC/DC converter - defines standardized performance tests for DC/DC converters used in voltage class B electric propulsion systems. The standard specifies test objectives, diagrams, operating points, environmental and cooling conditions, measurement procedures and the required test report format to verify converter loss, efficiency and thermal behaviour.

Key topics and requirements

• Scope and context
  • Applies to DC/DC converters in voltage class B propulsion systems; uses definitions and ambient/test-condition references from ISO 21782-1:2019 and voltage sub-classing in ISO 21498-1.
• Measurement of loss and efficiency
  • Test setup and diagram for DUT, supply, load and power meters.
  • Operating points defined in Annex B (p1…p18) cover combinations of output currents (0.2×I to I) and input voltages (maximum, rated, minimum) for long (1 800 s) and short (2 or 10 s) durations.
  • Record averages of input and output power (averaged over the last 1 s of each operating time).
  • Loss and efficiency are calculated from measured input and output power (efficiency = output power / input power × 100%).
• Temperature rise (thermal) test
  • Test diagram with temperature measurement points and thermometers.
  • Measure temperature at power-semiconductor/electrode parts and at coolant/air inlet and outlet (liquid or air cooling).
  • Recommended coolant temperature is 65 °C where technically feasible; coolant examples: ethylene or propylene glycol.
• Test conditions and reporting
  • Ambient conditions per ISO 21782-1; specified coolant flow/air flow minimums.
  • Test report content and templates provided in Annex A (common conditions, measured values, calculated results).

Applications

• Performance validation of automotive DC/DC converters during design verification and production acceptance.
• Thermal design verification and cooling-system validation for converters in electric vehicles (EVs).
• Supplier qualification, component characterization, and laboratory certification tests.
• Benchmarking efficiency and loss maps for system-level energy management and range optimization.

Who should use this standard

• EV OEMs, powertrain and electronics engineers
• DC/DC converter manufacturers and suppliers
• Independent test laboratories and certification bodies
• R&D teams focused on converter efficiency and thermal reliability

Related standards

• ISO 21782-1:2019 - General test conditions and definitions
• ISO 21498-1 - Specification of voltage sub-classes for voltage class B

Keywords: ISO 21782-4:2021, DC/DC converter, electrically propelled road vehicles, performance testing, efficiency, temperature rise, voltage class B, test specification, operating points, loss measurement.