TIDA-010062: The calculations of some variables.

? ?

Part Number: TIDA-010062

Tool/software:

Hi Experts,

I have some questions about the Lab4 of the TIDA-010062.

1. What are the EPWM1-A and EPWM1-B used for? It seems that the duty cycle of them are not changed during the whole period.

2. How to understand the following codes? What's the mechanism calculating TTPLPFC_ac_cur_ref_pu and TTPLPFC_ac_cur_ref_inst_pu?

Why should we use such a method to generate the duty cycle of EPWM3?

TTPLPFC_ac_cur_ref_pu = TTPLPFC_gv_out *
TTPLPFC_vBusAvg_pu / (TTPLPFC_vACRmsMeasAvg_pu);

TTPLPFC_ac_cur_ref_inst_pu = TTPLPFC_ac_cur_ref_pu *
                        TTPLPFC_spll_sine
                        + TTPLPFC_thetaOffset_pu * TTPLPFC_spll_cosine;

Best regards,

Power

9 months ago

0 ? ? 9 months ago

Prodigy 110 points

Hi,

Is there any update?

Best regards,

Power

0 Desheng, Guo 8 months ago

TI__Expert 6650 points

Hi,

1, EPWM1-A and EPWM1-B are used to trigger the MOSFET leg with line frequency, and they are operated as GPIO, other than PWM.

2, The function is using the output of voltage compensator to calculate the instanuous current reference to the current loop. And, the energy is avarage value and related to the Vin and Vout, so it need to be convert to the input current same with average, and then use the average value multiply a sine wave with the same phase of grid line, to get the instanuous value. The theta offset is used to compensate the X capacitance.

I suggest you learn the boost pfc control with c2000 in first before you goto totempole pfc.