Testing traction inverters & motor drives to LV 123 / LV 148
powertrain and drive engineering teams live inside a voltage window, and LV 123 / LV 148 is what defines its edges. With traction inverters, motor control units, on-board chargers on bidirectional HV DC with regeneration, the job is that the drive behaves across the whole DC input window, including regen — at the top of the band, at the bottom, and through every transition between them. Voltage-class bands is the whole test; 400 Hz never enters it. That calls for bidirectional DC supply spanning 0–800 V with ripple superposition and millisecond profile sequencing for HV work; 0–70 V with programmable milliohm output impedance for 48 V board-net work.
What you are testing
- Device under test
- traction inverters, motor control units, on-board chargers
- Bus
- bidirectional HV DC with regeneration
- Who buys this
- powertrain and drive engineering teams
What LV 123 / LV 148 does not cover
- 400 Hz
- harmonic immunity
- grid conformance
If your programme needs those, they come from a different standard and often different hardware.
The limits this test has to reproduce
A drive regenerates, so the supply has to sink as readily as it sources. That single requirement eliminates most unidirectional bench supplies before any other spec matters.
| Parameter | Value | Clause |
|---|---|---|
| HV_2b unlimited operating | 250–450 V | LV123 voltage classes |
| HV_3 unlimited operating | 520–750 V (circuit limit 800 V pk) | LV123 voltage classes |
| Overvoltage pulse slew | max 20 V/ms | LV123 §10.4 |
| LV148 unrestricted operating | 36–52 V | VDA 320 |
| LV148 transient overvoltage | 70 V for 40 ms | E48-02 |
| LV148 source impedance | 10–100 mΩ | VDA 320 |
The clauses ev-drive programmes actually face, as published in LV 123 / LV 148. See every limit in LV 123 / LV 148. Certification work should be run against the published standard.
What decides the rig here
The requirements that separate a system that can run this programme from one that only meets the headline numbers.
The supply must sink as well as source
A regenerating drive pushes energy back. Unidirectional supplies are eliminated at this requirement, whatever else they offer.
Battery emulation beats a real pack on a line
An emulated source is repeatable, always at the state of charge you asked for, and does not need charging between units.
Ripple superposition is usually the gap
Meeting the voltage window is straightforward. Superimposing the specified ripple across it is where bench supplies fail.
Other standards this DUT usually faces
Further reading on LV 123 / LV 148
- AQG 324 and SiC Modules: When the Named Guideline Does Not Cover Your Device
- The Battery Tester Voltage Window: Bought for 1500 V, Caught Out at 36 V
- High-Current Battery Testing: The Joint Fails Before the 8,000A Supply
- ISO 16750-2: The Code Letter Is the Specification, Not the Voltage
- 48 V and 800 V Answer to Different Documents, Not Just Different Voltages
- LV 123 and LV 148: Testing Across the Voltage Window, Not Just at Nominal
Send us the clauses you have to satisfy
We will come back with the source and load capability that covers them — and tell you plainly if something in your spec needs hardware we would not supply.
Talk to an engineer