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TIDM-1007: Control Loop Design of Totem-Pole Bridgeless PFC

Part Number: TIDM-1007
Other Parts Discussed in Thread: TMS320F280049C, TIDM-02008

Hi all,

I am a research intern at Havells India Ltd. We are designing and implementing a 1kW Bidirectional Totem-Pole Bridgeless PFC using SiC MOSFETs. We have completed the hardware design and are currently working on the control loop algorithm which is to be implemented on our TMS320F280049C microcontroller. We are currently referring the reference design TIDM-2008/TIDM-1007: Bidirectional Interleaved CCM Totem Pole Bridgeless PFC Reference Design Using C2000Tm MCU for the control loop design.

We plan to design the system in Simulink and generate auto-code which is to be ported into our microcontroller. We are facing issues in tuning our PI controllers. Currently our system is stable at higher loads and goes unstable at lighter loads in the simulation. We tuned our PI controllers using trial and error method hence we cannot explain the reason for choosing such values and nothing is learnt out of this. I am looking for some resources which I can refer to accurately design my controllers. Also, if any of the authors of this reference design (Manish Bhardwaj, Jongwan Kim) can give us some insights on how they designed the control loop, it would be of great help. 


  • Hi,

    Did you derive the transfer function of the PFC? The controller design has to be start from the duty to output transfer function (plant model).

    Based on the plant mode, you need to design the compensator to get the desired cross over frequency, gain/phase margins.

    TIDM-02008 User's Guide also includes controller design in page 9.



  • Hi,

    The document has only the plant transfer function. There is no explanation on how it is derived. Only the generalized control system blocks are present. There is no information on how to design the PI controllers and how to choose its respective constants.

    I found a reference design from Infineon on a classical boost PFC and it had the full control loop design. Will the equations used by Infineon work for us? I tried deriving from the basic Kirchhoffs laws for the Totem-Pole PFC and I arrived at similar equations. The reference design from Infineon is here: PFC CCM Boost Converter - 300W Design Example Using XMC 1400-AN-v01_00-EN.pdf

  • Hi,

    The typical compensator design stars from control to output transfer function. the role of compensator is to get the desired open loop response.

    Below is referenced from the reference guide that you mentioned. (page 15)

    Based on the uncompensated bode plots in Figure 14, the compensator was designed with the following zero, pole and gain values. This results a controller bode plot as shown in Figure 15.

    It clearly states that the compensator was designed based on the uncompensated bode plot (plant). It was not derived from universal equations. The equation (Eq.7) is  just a representation of the derived transfer function.

    The below link  gives the controller design procedure and hope this is helpful.