Power Analyzer for EV Inverter Efficiency Testing: Recommended Models

A multi-brand guide to selecting a precision power analyzer for EV inverter work, with channel count, bandwidth, current sensing, and uncertainty requirements.

Last updated: 2026-09-18

The measurement system is the product

For EV inverter efficiency, the power analyzer, voltage leads, current sensors, synchronization, wiring topology, and averaging rule form one instrument system. The buyer must define DC-link voltage and current, inverter phases, motor/dynamometer points, switching frequency, current sensor ranges, and the allowable uncertainty at both rated and low load.

Recommended power analyzers

| Model | Useful published capability | Best fit |

| --- | --- | --- |

| Yokogawa WT5000 | Up to seven user-swappable elements, 18-bit resolution, 10 MS/s, 1 MHz power bandwidth, 0.03% basic power accuracy | Multi-phase inverter and motor efficiency work needing flexible element configuration |

| Hioki PW8001 | Up to eight input units; U7005 supports DC to 5 MHz, 18-bit, 15 MS/s; optional motor analysis | E-axle, SiC/GaN inverter, and multi-channel systems where current-sensor phase correction matters |

| ITECH IT9121E / IT9100 series | Chinese brand power-analysis platform for AC/DC electrical measurement and automated benches | General inverter, charger, and power-electronics test systems where domestic service and integration are important |

What to specify in the purchase brief

1. Draw the complete DC input, inverter output, motor, and auxiliary measurement paths.

2. State the channel count and whether each input is direct voltage, shunt, or an external current sensor.

3. Require accuracy at the actual frequency, power factor, current range, and operating temperature.

4. Require one common trigger/time base for all input and output channels.

5. Require raw/exported data, configuration records, and a repeatable efficiency calculation window.

Sensor and wiring checks

A 0.03% analyzer specification does not mean the finished system is 0.03% accurate. Include current-sensor accuracy and phase error, wiring, voltage range, calibration interval, sensor position, and low-load error in the uncertainty budget. For high-voltage inverter benches, record CAT ratings, isolation boundaries, and emergency-stop coordination separately from the performance specification.

Acceptance test

Run at least three real operating points: low-load, nominal torque/speed, and the highest switching-stress point. For each, retain measured input and output power, operating-point definition, sensor identification, averaging length, and calculated efficiency.