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LMG3410EVM-018: Bi-directional controlled rectifier

Sam Ref
Expert 1610 points
Part Number: LMG3410EVM-018
Other Parts Discussed in Thread: TIDA-010062, TIDM-1007, TIDM-02008

Hello,

We are trying to implement Bi-directional 3-phase Controlled rectifier + PFC. Bi-directional where input can be provided to the DC side or AC side & Controlled where DC side can vary from 48 to 400VDC. Further, we prefer to use the new GaN power switches.

 

Designs & Questions

* TIDA-00961 (GaN). If this design is adapted to three-phase we will realize the PFC sought. It seems that this design does not allow controlling the DC voltage level. We have been advised (by TI senior engineer) that this design would not support 48VDC, only 400VDC with much voltage ripple

Questions;

  1. What is the ripple level as percentage of the output DC volt?
  2. The design produces 400VDC. This is a controlled GaN rectifier and further has two controlled MOSFETs. For sure the system has enough degrees of freedom to control both DC output and power factor and hence we must be able to reduce that DC volt output as well as PFC? What would be the minimum DC level that we can realize? And why cannot we have full control over the DC range.
  3. Why have not we used GaN switches to replace the auxiliary MOSFET switches.
  4. Is this design bi-directional? Can we supply 400VDC and get AC output?

 

* TIDM-1007 (GaN). This design is very similar to TIDA-00961.

Questions;

  1. The location of the auxiliary MOSFETs has changed as compared to TIDA-00961. What does it do?
  2. Do we get higher or lower DC voltage ripple as compared to TIDA-00961?
  3. Does this design generate three phases out of a single phase? If so are these 120degrees phase shifted? If so why do we do that?
  4. Same 4 questions posed for TIDA-00961.

 

* TIDA-010062 (GaN). This is a two-stage design PFC à DC-DC.

Questions;

  1. Is this design bi-directional? Can we supply 400VDC and get AC output?

 

* TIDA-00951 (no GaN). This is a design that allows 48VDC 400VDC bi-directional

Questions;

  1. Would you recommend using TIDM-1007 + TIDA-00951 OR TIDA-010062 to realize the target listed above (ie bi-directional controlled rectification +PFC)
  2. Does TI have any reference design that realizes bi-directional 48VDC-400VDC using GaN?

Regards

Sam 

 

  • 0
    TI__Genius 16390 points

    Hi Sam,

    Thanks for the interested and detailed investigation on GaN. We will get back to you with answers and comments in next few days.

    Thank you!

    Regards,

  • 0
    TI__Genius 16390 points

    Hello Sam,

    Let me try to answer some of the questions.

     TIDA-00961


    1. As specified in the user guide, the pk-pk voltage ripple will be around 25V.

    2. It works like boost converter where the output voltage will be higher than the input voltage. The output voltage will be 380V min.

    3. If you are talking about line frequency FET, then the advantage of GaN is not so obvious at low switching frequency. By using GaN will add system cost.

    4. Since it's CRM PFC, it would be really difficult to control. Doing it bidirectional will be even more difficult.

     TIDM-1007 


    1. I'm not quite follow you on the location part. Are you talking about the line frequency MOSFET? What do you mean by location?

    2. From the results collected, the voltage ripple at the same power level, the TIDM-1007 will be lower.

    3. This design is an interleaved design. It's converting one phase AC to DC. Interleaved to make the output capacitor smaller since the inductor ripple added together will be smaller. The control of the switch will be 120 degree out of phase.

    4.1 The ripple level will be in the test waveform here: https://www.ti.com/lit/ug/tidud61c/tidud61c.pdf?ts=1592873514510&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FTIDM-1007

    4.2 Same reasoning as previous.

    4.3 Same reasoning as previous.

    4.4 This design is bidirectional.

     TIDA-010062 


    No this one is not bidirectional.

     TIDA-00951

     1. TIDM-1007 + TIDA-00951 seem to be a viable solution. Does the power level meets your need? Again, 010062 is not a bidirectional solution.

    2. Currently no. Most of customer is looking at single direction or bidirection with higher DC output level at this moment.


    Please let me know any follow up comments and questions.

    Regards,

  • 0 in reply to Yichi Zhang.
    Expert 1610 points

    Thanks Yitchi

    If we want a bi-directional PFC design (1.5-2KW)

    1. we have 2 reference designs available. TIDA-00961 & TIDM-1007/02008. Correct?
    2. Is there any further reference designs available?
    3. TIDM-1007/02008 seems to excel as it has less ripple at the DC side. Also, it can work with either single phase or three phase. Correct?

    Regards

    Sam

  • 0 in reply to Sam Ref
    TI__Genius 16390 points

    Hello Sam,

    1. For bidirectional, TIDM-02008 is a good reference design. TIDA-00961 is not bidirectional.

    2. For bi-directional PFC, the above-mentioned is the only one currently available. Feel free to check back on https://www.ti.com/power-management/gallium-nitride/reference-designs.html#search?famid=3321 this page if you need to find other GaN related designs.

    3.  It's single phase AC input. The three DC phase you saw is three parallel module for interleaving topology.

    Please let us know of any further questions.

    Regards,