TIDA-00652: Capacitor regulator at the input

Aswathy Kanth

Part Number: TIDA-00652
Other Parts Discussed in Thread: DRV10983

Hi,

I am using a similar design as that of TIDA-00652. ie, Buck PFC+ DC-AC Converter+ BLDC Driver for a BLDC fan application. The circuit was designed for 90-265Vac input range. In the 230Vac input, I connected a series capacitive regulator for fan speed control, then the buck PFC is going to hiccup mode. I understand that, because of high impedance at the input, the voltage is drooping & power supply is not getting sufficient current. Do we have to go for a different architecture to use a series capacitive regulator for speed control? do you have any reference design available for BLDC fan with normal wall mounted regulator speed control option? Kindly support.

Thanks & regards,

Aswathy

over 4 years ago

0 Hawken Li over 4 years ago

TI__Intellectual 2585 points

Hi,

I'm not sure what kind of issues that you need add more capacitors. For the motor control, the DRV10983 is an open speed loop controller which cannot support a constant speed control. It would not solve any speed accuracy problem when you change the capacitor. If the 24V is unstable at 230V AC, please check the PFC part parameters.

B.R

Hawken

0 Aswathy Kanth over 4 years ago in reply to Hawken Li

Intellectual 700 points

Hi,

Thanks for the reply. Do you have any reference design available for bldc fan speed control with normal capacitive type regulator?

Regards,

Aswathy

0 Hawken Li over 4 years ago in reply to Aswathy Kanth

TI__Intellectual 2585 points

Hi, We do have a close speed loop design with DRV1098x. Please refer to www.ti.com/.../TIDA-01585

0 Aswathy Kanth over 3 years ago in reply to Hawken Li

Intellectual 700 points

Hi,

The paper states that "The board accepts the speed command through pulse-width modulation (PWM) or through analog voltage from an external signal". Actually, my requirement of speed control is through a capacitive regulator in the input as shown below. Do you have any solution for this? When we are connecting the capacitive regulator in the input, the buck pfc is not working & is going to hiccup mode. Do we have to go for any other architecture/circuit to achieve speed control using input regulator? Please share your thought on this.

0 Hawken Li over 3 years ago in reply to Aswathy Kanth

TI__Intellectual 2585 points

i cannot open your image. could you resend it? i'm not sure what kind circuit you designed. But from your description, I suggest to tune the motor firstly. After motor can operate normally, tune the pfc.

0 Aswathy Kanth over 3 years ago in reply to Hawken Li

Intellectual 700 points

My issue is when capacitve regulator is connected in serires at the input, the AC-dc is not working. Do you have any solution for this? Any other circuit do we need to follow?

0 Aswathy Kanth over 3 years ago in reply to Aswathy Kanth

Intellectual 700 points

0 Hawken Li over 3 years ago in reply to Aswathy Kanth

TI__Intellectual 2585 points

Hi,

Your target is to change the fan speed, either to change the output voltage from buck PFC, either to change the MCU output of PWM Freq/duty to change the motor speed. I cannot understand how to use a serial capacitors to change the motor speed. Please understand the design firstly then change the design. You cannot change the motor through changing the AC voltage. It is a buck PFC circuit. The output voltage is constant.

0 Aswathy Kanth over 3 years ago in reply to Hawken Li

Intellectual 700 points

Hi,

Please see comments below

Your target is to change the fan speed, yes. either to change the output voltage from buck PFC. either to change the MCU output of PWM Freq/duty to change the motor speed. I cannot understand how to use a serial capacitors to change the motor speed. Capacitive fan regulators are available in the market for BLDC fan speed control. https://www.amazon.in/Generic-Anchor-Panta-Speed-Regulator/dp/B07FS9X2Z5/ref=asc_df_B07FS9X2Z5/?tag=googleshopdes-21&linkCode=df0&hvadid=396985556319&hvpos=&hvnetw=g&hvrand=7990985097772358082&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007776&hvtargid=pla-949572753789&psc=1&ext_vrnc=hi

Please understand the design firstly then change the design. You cannot change the motor through changing the AC voltage. It is a buck PFC circuit. The output voltage is constant. Yes. I understand that the voltage will be constant. That is why I am looking for a variable voltage solution with high PF. Do you have any solution?

0 Hawken Li over 3 years ago in reply to Aswathy Kanth

TI__Intellectual 2585 points

Hi,

The theory of capacitor regulator is to change the AC phase to tune the output power then change the AC fan speed. It can be used for only AC fan. If you want to change the BLDC fan speed, you need add an additional circuit to change the phase signal to output voltage signal. A much easier way is to use a resistance-based speed controller tune the PWM signal through MCU. It would be preferred and much safety without tuning any high-voltage circuit.

0 Aswathy Kanth over 3 years ago in reply to Hawken Li

Intellectual 700 points

Thanks for the reply. Do you have any resistor based speed controller solution available with you?

0 Aswathy Kanth over 3 years ago in reply to Aswathy Kanth

Intellectual 700 points

We are also looking for high PF solution with capacitor regulator based speed control

0 Hawken Li over 3 years ago in reply to Aswathy Kanth

TI__Intellectual 2585 points

Hi,

Please change your mind to low voltage BLDC motor control. Our design has an active PFC inside which can support a 95+% PF. You can easily change the MCU sw to support the resistance based speed regulator.

Please close this discussion by click resolved button.

0 Aswathy Kanth over 3 years ago in reply to Hawken Li

Intellectual 700 points

Hi,

Thanks for the support provided so far. We could successfully change the motor speed with capacitive regulator using a different open loop topology(with varying the input voltage & acheived high PF)!!!!.

You can close this post.

Regards,

Aswathy

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TIDA-00652: Capacitor regulator at the input