Overview
IEC TS 63156:2021 - "Photovoltaic systems - Power conversion equipment performance - Energy evaluation method" provides a procedure for evaluating the energy conversion performance of power conversion equipment (PCE) used in photovoltaic (PV) systems. The Technical Specification covers both stand‑alone and grid‑connected converters (inverters) and defines how to calculate expected energy yield from inverter performance using site‑specific solar load profiles. It extends standard efficiency test procedures to account for real‑world dynamic conditions and can be used as the PCE energy evaluation method referenced in IEC TS 61724‑3.
Key topics and requirements
- Energy conversion efficiency: Defines the ratio of AC energy delivered to DC energy received over a measurement period (ηCONV) and provides a framework for measuring and calculating it.
- MPPT efficiency: Includes definitions and methods for evaluating maximum power point tracking performance under changing conditions.
- Static and dynamic evaluation: Specifies separate test sequences and measurement conditions for static (steady‑state) and dynamic (time‑varying irradiance) performance of PCE.
- Weighted efficiency calculation: Describes how to compute an overall (site‑weighted) energy conversion efficiency using solar load profiles and weighting factors to reflect local irradiance distributions.
- Irradiance characterization: Addresses analysis of irradiance profiles and the rate of change of irradiance (R) to capture transient behavior relevant to converter performance.
- Test circuits and conditions: Specifies energy efficiency test circuit arrangements and required measurement conditions for repeatable evaluation.
- Workflow and calculation flowcharts: Provides procedural flowcharts for test execution and energy conversion efficiency calculation.
Practical applications and users
Who uses IEC TS 63156:2021:
- Inverter and PCE manufacturers for performance claims, R&D and product benchmarking under realistic irradiance profiles.
- Test laboratories and certification bodies performing energy‑based efficiency testing beyond steady‑state methods.
- PV system designers and integrators who need site‑specific energy yield predictions incorporating converter dynamics.
- Performance analysts and O&M teams comparing actual system output to modeled expectations (for use with IEC TS 61724‑3).
- Project developers and asset owners evaluating vendor equipment for long‑term energy yield and warranty assessments.
Typical applications:
- Predicting annual or seasonal energy yield accounting for dynamic converter response.
- Evaluating MPPT and transient behavior under fluctuating irradiance (clouds, shading).
- Comparative testing of PCE models for procurement and specification.
- Supporting performance modeling used in monitoring, loss analysis and contractual performance guarantees.
Related standards
- IEC 61683 - Procedure for measuring PCE efficiency (static tests)
- IEC 62891 - MPPT efficiency of grid‑connected inverters
- IEC TS 61724‑3 - PV system energy performance monitoring (uses IEC TS 63156 for PCE energy evaluation)
Keywords: IEC TS 63156:2021, photovoltaic systems, power conversion equipment, energy evaluation method, inverter performance, energy conversion efficiency, MPPT, dynamic efficiency, irradiance, PV energy yield.