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LMG34XX-BB-EVM: Power management forum

kai yan
Prodigy 75 points
Part Number: LMG34XX-BB-EVM
Other Parts Discussed in Thread: TIDA-00909, TIDA-00913, TIDM-02008, TIDA-00915, LMG3410R150, LMG3410R050, TIDA-01606

I have  seen LMG34xx GaN system-level evaluation motherboard, can you explain "this EVM is not suitable for transient measurements since it is an open loop board"?

  • 0
    TI__Genius 16390 points

    Hello Kai,

    Thanks for reaching out. Here the purpose of stating this is to emphasis this is an open loop board. Transient measurement here means the transient behavior to get the control loop stabilized etc. However, if you just feed in PWM signal, you can measure the switch node performance, slew rate, overshoot etc. 

    If you are paring this with the daughter card from TI, then please do the switch node measurement on the daughter card which has less inductance and yields more accurate measurement.

    Hope this helps.

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    I have seen their answer, and it solved my question. Each daughter card is a half bridge circuit. To have a single phase full bridge inverter I will need two daughter cards + two mother board + controller.

    Here are their links: Daughter card and mother board:

    Controller link:

    If the scheme works, can you provide a matching input/output device? Otherwise, we cannot use this inverter alone. If possible, please make a list of products for me.How much will this series cost.

  • 0 in reply to kai yan
    TI__Genius 16390 points

    Hello Kai,

    If you want to only evaluate the GaN performance, then a single motherboard and daughter card could allow you evaluate the switch node performance as well as the efficiency etc. 

    If you want to having working prototype for your design, it's suggested to have your own motherboard/daughter card design instead of using two motherboard+two daughter card (I don't think it will work in this case).

    We have reference design of three phase inverter - TIDA-01455, TIDA-00915, TIDA-00909 and TIDA-00913 available for evaluation, and there is a bidirectional PFC/inverter with interleaved configuration, TIDM-02008.

    You can start with these and proceed with a full bridge design.

    Please let me know if you have any questions.

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    Our laboratory needs a photovoltaic power generation inverter, the programmable one, so that we can achieve it by ourselves even without MPPT.

    What our laboratory needs to do is to control the parallel connection of multiple new energy devices, and the current equipment power of your company is too small, such as piccolo-based Solar Explorer Development Kit.

    The customer service has also recommended other ones, such as TMDSSOLARUINVKIT, but none is satisfied at present.

    We want to buy the finished product, but like the reference design, do we need to weld by ourselves?In this case, we are afraid that ourO own ability will not pass.

  • 0 in reply to kai yan
    TI__Genius 16390 points

    Hello Kai,

    Could you provide more details of your requirements? Such as input voltage, output voltage, output current, power level, as well as some special requirements such as prefer a digital controller etc.? With the requirements I can see if we have any available reference designs.

    Also what's the main reason for looking at GaN in this case?

    Thanks!

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    Hi Yichi,

    We mainly want to make the control system of the parallel equipment of photovoltaic power generation equipment, so we need an inverter to connect to grid Simulator or AC source. This inverter has better be a kilowatt level (above 2KW), and we want to find a DC source to replace its input voltage.
    As long as the inverter to meet the input as good.
    But we don't have a range of equipment at the moment, so we would like to ask if you can offer any solutions?
    For example, two sets of Piccolo-based Solar Explorer Development Kit are connected in parallel through the inverter, and then we do the parallel control system by ourselves.
    This Development Kit actually meets our needs, but the power is too small. Other teachers proposed to us that the previous MPPT and the analog output of photovoltaic power generation could be programmed by ourselves, and then they helped us design the scheme of two Daughter CARDS + two Mother Board + Controller.
    If this scheme works, can you provide his DC input equipment?
    And the corresponding AC source behind the inverter.

    Thanks,

    Kai

  • 0 in reply to kai yan
    TI__Genius 16390 points

    As our daughter card is only half bridge, I'm still not quite sure how are you going to make them become a full bridge inverter by using two daughter cards and two motherboards. Could you please elaborate on this?

    If you PV needs three phase AC output, then TIDA-00915 could be a good reference design as it uses C2000 for control and capable of going to 1.25kW. As you replace the LMG3410R150 device with higher rated power device such as LMG3410R050, you could go to higher power level.

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    Hi Yichi,

    The switch nodes of two half-bridge inverters are wired out, and the load is connected between the two nodes. Like this?

    Can you explain what is a reference design?
    Is it buying recommended parts and welding them in the lab?

  • 0 in reply to kai yan
    TI__Genius 16390 points

    Hello Kai,

    I doubt if this is going to work since there will be way too much parasatics by connecting two daughter cards together. Also by doing this, it will be very difficult to control since the propagation delay will be very different in different devices.

    A reference design is a design by TI for a popular end application. TIDA-00915 is a good example of the three phase inverter reference design. You could order it from TI for evaluation, and the design files are all available online if you want to take a closer look or make modifications.

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    Hi Yichi,

    what is "parasatics"? (You may have typed it wrong).  :)

    How does TIDA-01606 compare with TIDA-00915?

    For reference design, I know it's an end application, but if you don't offer a complete product, what things I need to buy? Do I need to choose one part by one? Do I have to assemble it by myself? I am very confused.

    We want to buy a set of equipment. Take TIDA-00915 for example, can you provide his DC input device and AC source? One inverter cannot be used by us, do you understand my meaning?

    Thanks,

    Kai

  • 0 in reply to kai yan
    TI__Genius 16390 points

    Hello Kai,

    Let me try to answer the questions.

    1. The parasatics is the parasitic capacitance and parasitic inductance associated with the long wire you are trying to connect the daughter cards. Too much of the parasatics will greatly reduce the performance and might damage the device due to the noise coupled or the overshoot of the switched node in high switching frequency application. Also the motherboard here does not have current/voltage sensing (it is meant to be an open loop device), and it might be difficult to do control with the motherboard+daughter card configuration here.

    2. TIDA-01606 requires input voltage at 800V-1000V while the TIDA-00915 needs input voltage of 200-400V. t

    3. The reference design the complete PCB you see in the image. You can buy the whole board and give appropriate input and start testing.

    4. For the last question, I assume you are talking about you need another DC-DC converter to boost up the voltage from the solar panel to the input voltage range that is acceptable by the inverter. For that, we do not have a reference design in GaN team for you regarding the DC-DC stage. The AC will be the output of the inverter, and the DC input voltage will be coming from the PV panel. For the DC-DC stage from the PV panel to the inverter, you might look into the boost converter/flyback converter TI has over here: https://www.ti.com/reference-designs/index.html.

    Regards,

  • 0 in reply to Yichi Zhang.
    Prodigy 75 points

    Hi Yichi，

    You have given me the answer I want.

    If I want to puchase: TIDA-01606 or TIDA-00915, is it showing that I need to buy all these devices? What are the respective prices for such a set?

  • 0 in reply to kai yan
    TI__Genius 16390 points

    Hello Kai,

    I see your point now. Normally the whole module would be available for purchase, but not these two apparently. Could you accept my friend request and I can work with you offline.

    Regards,