HV Solar DC-AC Kit, running Piccolo MCU; using 120VAC -->380VDC PFC; without GUI

Hi Clay,

The GUI largely just edits variables in the C project (ie the GUI doesn't do much processing) so you'll find all these settings as variables in the underlying C project.

I believe that you're interested in the Gui_wUtility_Setting and Gui_Utility_Setting_Enable variables.


Thank you,
Brett

Hi Brett,

I've been temporarily side tracked. Can I get some clarification about running HV Solar DC-AC code without a GUI?

There is a comment in main.c saying, " Use this section only if you plan to instrument your application using the Microsoft C# freeware GUI template provided by TI."

Followed by:

#ifdef FLASH

#endif //(FLASH)

Can I just comment this code out?

Thanks.

Hi Clay,

What you're seeing is a bit misleading. Your question here revolves around code and lines of software that should be cleaned up.

I'll give a bit of insight though:
1) If the code sees that the value of FLASH is '1', then the code between the #ifdef and #endif will be active. If FLASH is '0' then the code between will be commented out by the compiler. I say that this is misleading because there is no code between #ifdef and #endif.
2) Further, based on the above you now know that the INITIALISATION - Gui Connections section is empty. Safely ignore lines 756-765.
3) For future reference FLASH is defined in the project settings. Depending on your configuration FLASH will be defined as '0' or '1'.

To run the C project you'll basically have to touch the same variables in the same order as you did in the GUI. In the project, these variables will precede with a Gui_.


Thank you,
Brett

Hi Brett,

My setup is as documented in SPRABR5 except without the DC-DC kit input. With 380VDC in, my inverter board is running 212 VAC @ 60 Hz out. It has from the beginning. Obviously, I expect it to run at 120VAC @ 60HZ.

The code seems to working as documented, including changing INCR_BUILD==1. The states change fine, the LEDs light accordingly and the output turns on without any error after SW1 is pressed and released. The sine output is clean and I can run a small AC fan load; the out put is just 212VAC, not 120VAC.

My speculation is that correct initialization is being over written by GUI info, which I am not using. I was hoping to disable the GUI code to verify my speculation. At this point, I will be content merely changing the output from 212VAC to 120VAC any way that works just to continue my system evaluation.

I originally started with the Concerto board which supports a multi-core MCU running 2 discrete code modules. I tried to get the multi-core project to build, but I kept getting obscure build errors, using code from the stick. I never had any build trouble using the Piccolo based project code.

If I can't get past this problem running the Piccolo MCU, can you send me the entire clean project and clean build for the Concerto version of the HV Solar DC-AC inverter? At least I could use the debugger in circuit and access the GUI.

Thanks.

Hi Bret,

Hoping you had a good Christmas and New Years Break.

My project has FLASH =1 active. Does this indicate I'm running in GUI mode, even though I don't have one connected?

How do I toggle this Project setting?

For grins, I tried my present Piccolo configuration as a Build 2. Build 1-Open Loop doesn't provide feedback or control loops, but I'm thinking the Open Loop Build suites my application.

The result of a Build 2 was that the AC RMS output increased from 208VAC to 380VAC, similar to my 380VDC input, so it appears feedback may have worked, just not getting the output voltage I want. Reverting back to Build 1 decreased my output back to 208VAC...not the desired 120VAC.

The GUI_* variable values look fine in the code. I just don't think those are what is actually being used by the MCU. Everything I'm seeing indicates the code is functioning otherwise.

Thanks.

Clay,

Sorry for delay in replying. The software we provide with the kit is current source inverter and does not regulate the output voltage. And the output voltage will be whatever the load and power fed relation will make it for build level 2 and level1. 

Can you elaborate if you want a voltage source inverter? 

Then the code we provide for the kit is not directly usable, it does not have the outer voltage control loop and will need to be modified. 

Regards,

Manish Bhardwaj

Hi Manish,

Thanks for the reply.

I do want a voltage source inverter for this kit. Do you have any baseline true sine 120VAC code compatible with this kit available for me to to start with?

Documentation indicates current sourcing on the input side, which I understand due to the nature of the solar panel application, but I wasn't sure about the output side, since it was designed to be switched into and phase locked to a 120VAC home circuit. I was in the process of coming to the realization that the kit is a current source, not a voltage source on the output side. Thank you for the confirmation.

Since I'm running CV on the input, documentation indicates in one place the outer voltage loop needs disabled 1st and in other places documentation indicates the outer voltage loop disables automatically. Based upon what I've seen so far and some simple code mods it seems to be the former, not the latter. Documentation also indicates that I can control the output voltage via disabling the voltage loop controller and modifying dwVoltageLoopOutConst realtime. I've seen promising results so far.

Waiting for your next reply concerning my application. Please acknowledge receipt.

Clay,

As this is a solar inverter it needs to run two loops

1. Inner current Loops

2. Outer Voltage Loop which regulated the DC Bus (required for MPPT operation)

As the kit has been designed for connection to the grid the current compensators have been tuned assuming there is a grid present and this makes the current control simple. 

In the documentation if it says that the outer voltage loop is disabled/enabled it refers to the DC Bus control loop and not the voltage of the inverter output which is not controlled by the SW associated with the kit. 

For what you are trying to do you will need an outer voltage loop on the inverter output voltage, and the inner current loop may need to be re-designed. In this case as the load can vary the performance of the inner current loop can vary. 

Please let me know if you are looking at a specific page in the documentation where it says the output voltage of the inverter can be controlled. And i'll investigate if there is a hidden mode i am not aware of :D

FYI some users have successfully use the kit as output voltage controlled  inverter (like a UPS), however i am fully aware of the control and methodology followed to achieve this. 

regards

Manish Bhardwaj

Also i looked for dwVoltageLoopOutConst references and the documentation says if MPPT is not available then we can use dwVoltageLoopOutConst directly to modify the current output of the board. The current output will translate to some voltage at the output and the relation between the dwVoltageLoopOutConst and otuput voltage is determined by the load.

Hi Manish,

Thank you for you time and your help. Your latest reply is what I was previously referring to.

You previously said, "FYI some users have successfully use the kit as output voltage controlled inverter (like a UPS), however i am fully aware of the control and methodology followed to achieve this. "

Please share.

Is it possible to mark up a build 1 or build 2 diagram? Example code is better.

Clay,

Do you know what load will be connected to the inverter or it can be anything?

regards
Manish Bhardwaj

Hi Manish,

It might be anything.

Clay,

As i had mentioned this is not a supported mode for the kit, however i have pinged my colleagues and will give you an answer in another day or so if by any luck or chance we have anything..

I do not know about the implementation of people who have used this kit for voltage mode control, just the fact that is has been used, so don't have anything to share for that unfortunately.

regards
Manish Bhardwaj