# Drive power measurement

**URL:** <https://forum.plexim.com/t/drive-power-measurement/2937>\
**Category:** PLECS\
**Created:** [March 23, 2026, 2:57am UTC](https://forum.plexim.com/t/drive-power-measurement/2937 "2026-03-23T02:57:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ssq](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@ssq](https://forum.plexim.com/u/ssq)\
**Post date:** [March 23, 2026, 2:57am UTC](https://forum.plexim.com/t/drive-power-measurement/2937/1 "2026-03-23T02:57:32Z")

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how to measure the bus power and output power of the drive. The bus power I currently measure is 7721.2637W, and the measured output active power of the drive is 7721.2315W, while the total inverter IGBT losses are 199.8W, which does not add up. The current measurement method is as follows: bus power is measured by taking the product of the bus voltage and bus current after the capacitor and before the inverter bridge, and then passing it through a Periodic Average module. Output active power is measured using the two-wattmeter method based on the inverter output line voltage and current, and then pa

 ![2](https://europe1.discourse-cdn.com/flex006/uploads/plecs/original/2X/f/f93ce88b600de02170747b9960875f744bdbf3dc.png)

 ![3](https://europe1.discourse-cdn.com/flex006/uploads/plecs/original/2X/c/c390ce911e2262a822f89a4439cc8a76c0a97320.png)

ssed through a Periodic Average module.

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**Author:** ![Munadir\_Ahmed](https://dub1.discourse-cdn.com/flex006/user_avatar/forum.plexim.com/munadir_ahmed/32/1540_2.png) [@Munadir\_Ahmed](https://forum.plexim.com/u/Munadir_Ahmed)\
**Post date:** [March 26, 2026, 1:27pm UTC](https://forum.plexim.com/t/drive-power-measurement/2937/2 "2026-03-26T13:27:24Z")

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Hi ssq,

Please have a look at [Formula for calculation of efficiency - #2 by RetoChristen](https://forum.plexim.com/t/formula-for-calculation-of-efficiency/2766/2) for a detailed explanation on why you are seeing the discrepancy in your efficiency calculation and how to measure efficiency in PLECS. Let me know if you have any additional questions or if anything is unclear.