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I'm familiarizing myself lately with the usage of ESC (Electronic speed control).

I'm unable to determine when is it the best option to chose ESC over H-bridges? - in terms of advantages and disadvantages.

Why do -at least from what I've seen- people us ESC to drive and control brush-less DC motors rather than H-bridges?

What is the principle of operation of ESCs? I mean as for H-bridges it is a simple switching circuit of 4 MOSFETs transistors, but what is the case for ESCs?

Adel Bibi
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    Similar question was asked recently here: http://electronics.stackexchange.com/questions/102800/what-are-the-advantages-of-an-esc-over-a-pwm/102801#102801 – Spehro Pefhany Mar 15 '14 at 21:14

2 Answers2

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Quite a few ESCs use H bridges as the motor output stage so, in effect you are comparing a "system" made up of components, with one of those components. Basically a H bridge is used in a lot of ESCs but a H bridge on its own isn't an ESC.

A helicopter would use a collection of parts that could be described as an ESC but it won't use a H bridge; it would use open collector/drain transistor drivers because that is more efficient than a H-bridge. A H bridge is better suited to RC cars because you might want to run motors in reverse or apply dynamic braking.

Andy aka
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you can use two SN754410s to make a poor man's esc (might not be as strong/accurate as a real one, but it works). You just want to make an algorithm that creates the right waveforms on the three nodes of the motor. Take a look here for the waveform: https://e2e.ti.com/blogs_/b/motordrivecontrol/archive/2013/11/08/generate-your-own-commutation-table-trapezoidal-control-3-phase-bldc-motors-using-hall-sensors you will notice you need positive negative and neutral. Positive can be created by driving the SN754410 input pin high, and negative by driving it low. You must use another pin to set the enable low in order to create a neutral.

Sam Louis Milligan
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