Application Case: Solar Inverter Efficiency Verification Before Type Testing

An anonymous solar-inverter manufacturer workflow that selected a Yokogawa power analyzer and aligned DC input, AC output, sensor calibration, and averaging before external verification.

Last updated: 2026-09-18

Project context

A commercial solar-inverter manufacturer was preparing a new three-phase unit for internal verification before sending samples to an external laboratory. The product team reported an efficiency figure from its bench, while the compliance group obtained a different value with another analyzer and current-sensor arrangement. Neither result was necessarily wrong, but the operating point, averaging window, and sensor phase behavior were not identical.

How the bench was built

The test group drew the energy path from PV simulator to DC input and from the inverter's AC output to the grid simulator. It identified voltage and current measurement points on every relevant conductor, the current-sensor model and calibration date, inverter control mode, DC input level, AC power level, power factor, thermal stabilization rule, and calculation interval. A run only became valid after the inverter operated stably at the defined point.

Equipment selected

The laboratory selected a Yokogawa WT5000 because its modular multi-element arrangement covered the DC input and three-phase output with one synchronized chassis. The purchase package included the correct current elements/sensors and software export pathway. Hioki PW8001 was evaluated for its eight-channel architecture and high-frequency U7005 input option; it is the stronger choice when the same lab will extend to e-axle or high-switching-loss work.

Result in use

The first comparison did not reveal a software error. It showed that one earlier setup used a different averaging interval and a sensor whose phase performance was not included in the uncertainty discussion. Once the system was standardized, the teams could compare results across inverter variants and identify true efficiency shifts rather than test-bench variation.

What to verify before publishing

Check the claimed inverter class, operating-point grid, standards context, and whether your customers normally use a PV simulator plus grid simulator. The selected instruments and workflow are grounded in common solar-inverter practice but must be approved by your technical reviewer.