How to reduce input power consumption?

Ajay P

Hi,

1. I need to know about the methods to improve efficiency or reduce input power consumption of BLDC motor controller. If the input current is not stable, how can we stabilize the input current?

2. Does heating of current sense resistor a cause of increase in input current instability?

3. Does noises in the gate pulse of the inverter a cause of input current instability?

over 2 years ago

0 Akshay Rajeev Menon over 2 years ago

TI__Mastermind 23426 points

Hey Ajay,

1) There are many ways to reduce power loss in BLDC motor drivers. Is there any specific part of the driver you are concerned about? Is this for integrated MOSFET drivers or gate drivers?

For example, the MOSFETS, or integrated regulators?

Or are you more interested in PCB layout considerations to improve power consumption?

Please consult the following links on improving thermals.

https://www.ti.com/lit/an/slva959b/slva959b.pdf?ts=1664307040485

https://www.ti.com/lit/an/slva938a/slva938a.pdf

Ajay P said:
If the input current is not stable, how can we stabilize the input current?

Please consult point 3).

2) In theory the current flowing through a resistor can fluctuate its value leading to slightly less accurate CSA output. However, in practice they don’t heat up that much and shouldn’t be a point of concern.

3) So, one should design their system to avoid large spikes in voltage at the CSA inputs to reduce noise. You can do this by adjusting the IDRIVE settings of the driver to control slew rate of the MOSFETS and follow proper PCB layout practices to reduce the effects of parasitics.

One can also add external components to mitigate the effects of any transients. Please consult the following app note for more information on system design considerations.

https://www.ti.com/lit/an/slvaf66/slvaf66.pdf

I might also suggest checking out the following E2E FAQ on thermal calculator.

https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1078268/faq-bldc-integrated-mosfet-thermal-calculator?tisearch=e2e-sitesearch&keymatch=faq%3Atrue

Best Regards,

Akshay