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TIDM-HV-1PH-DCAC: TIDM-HV-1PH-DCAC Controller Explanation

Phillip Karls
Prodigy 80 points

Part Number: TIDM-HV-1PH-DCAC

The controller running on the TIDM-HV-1PH-DCAC gets boiled down to the following:

voltage_error= invVoRefInst - invVoInst;
gv_out= DCL_runDF22_C1(&gv_pr1, voltage_error)
+ DCL_runDF22_C1(&gv_r3, voltage_error)
+ DCL_runDF22_C1(&gv_r5, voltage_error)
+ DCL_runDF22_C1(&gv_r7, voltage_error);

gv_lead_lag_out= DCL_runDF22_C1(&gv_lead_lag, gv_out);
invIiRefInst=(gv_lead_lag_out);

gi_out= DCL_runDF22_C1(&gi, (invIiRefInst - invIiInst));

invDutyPU= (gi_out+invVoInst)/invVbusInst;

I have a few questions:

1. Can anyone explain the reasoning why the output of the voltage controller (gv_lead_lag_out in this case) is considered  the "current reference" as described on page 12 of the Design Guide? I am assuming I am missing a simple mathematical justification somewhere.

2. Can anyone explain the final calculation of invDutyPU? It looks like it's possibly gi_out / invVbusInst + DFF (invVoInst/invVbusInst), but I am unsure.

3. Would using a modified unipolar modulation scheme have any impact on the above calculations?

Lastly, according to this post:

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/998672/tidm-hv-1ph-dcac-issue-with-tidm-hv-1ph-dcac_voltage-source-inverter-evm?tisearch=e2e-sitesearch&keymatch=TIDM-HV-1PH-DCAC#

the reference design was only tested with resistive loads. Can anyone confirm this controller works for non-linear loads?

I appreciate the support!

Phillip

  • 0
    TI__Genius 12225 points

    1. This is always the case for a two loop control system. Here outer loop is voltage. This loop tries to regulate the output voltage and accordingly commands the needed current to achieve that. That's why Voltage loop output is the reference or command current for the inner current loop

    2. This is the inverter output voltage and DC bus voltage feedforward calculation. Pls see the documentation

    3. PWM modulation can be different. No impact as long as the control scheme is not changed.

     The design has been tested in UPS mode (voltage source output) with a non-linear load.

    Shamim