Overview
IEC 62891:2020 specifies a standardized procedure for measuring the maximum power point tracking (MPPT) efficiency of inverters used in grid‑connected photovoltaic (PV) systems. The standard covers both static MPPT efficiency (steady-state ability to find the MPP) and dynamic MPPT efficiency (response to irradiance fluctuations). Based on the static MPPT efficiency calculated per IEC 62891 and the steady‑state conversion efficiency measured according to IEC 61683, an overall inverter efficiency can be derived. Dynamic MPPT performance is reported separately.
Keywords: IEC 62891, MPPT efficiency, grid‑connected photovoltaic inverters, static MPPT efficiency, dynamic MPPT efficiency, PV inverter testing.
Key topics and technical requirements
- Scope and applicability
- Procedure applies to grid‑connected PV inverters and may also be used for devices with MPPT (e.g., charge controllers, optimizers).
- Measurement methodology
- Defines test set‑up, measured and calculated quantities, and clear procedures for static and dynamic MPPT tests.
- Static MPPT tests assess accuracy across representative operating points; dynamic tests use defined irradiance/voltage/time profiles to evaluate tracking under transient conditions.
- Test apparatus requirements (Annex A)
- Requirements for PV generator simulators, AC supplies, transient stability, dynamic characteristics and calibration/uncertainty are specified.
- Dynamic test profiles (Annex B)
- Standardized test sequences and ramp profiles for realistic irradiance fluctuations and start/stop behavior.
- PV generator models (Annex C)
- Reference current–voltage (I/V) and power characteristics for different PV technologies to ensure repeatable tests.
- Efficiency weighting and normalization (Annexes D & E)
- Weighting factors for regional efficiency metrics (e.g., European, CEC) and procedures to express efficiencies normalized to rated AC power.
- Reporting
- Static MPPT efficiency is combined with IEC 61683 conversion efficiency for an overall figure; dynamic MPPT efficiency is reported separately.
Practical applications and users
- Manufacturers - optimize MPPT algorithms, validate product performance and support datasheet claims.
- Test laboratories & certification bodies - perform repeatable MPPT efficiency measurements for conformity, performance labeling and certification.
- System designers & integrators - estimate real energy yield, inform inverter selection for sites with variable irradiance.
- Researchers & consultants - compare MPPT strategies and quantify transient tracking losses for modelling and optimisation.
- Regulators & procurement - set test-based performance requirements for incentive programs or procurement specifications.
Practical benefits include consistent, repeatable measurements for product comparison, improved accuracy in energy-yield estimation, and better understanding of transient losses due to MPPT behavior.
Related standards
- IEC 61683 - Procedure for measuring steady‑state conversion efficiency of power conditioners (used together to compute overall efficiency).
- IEC TS 61836 - PV terms and definitions.
- EN 50160 - Voltage characteristics of electricity supplied by public distribution networks.
Keywords (SEO): PV inverter testing, MPPT performance testing, photovoltaic standards, IEC 62891:2020, inverter efficiency measurement.