Clear the trip by writing 1 to the CLLLC_clearTrip variable. The
converter will operate in open loop as the
CLLLC_closeGvLoop variable is not yet set to “0”.
As there is no soft start implemented in the
firmware, first soft-start the voltages on the
primary and secondary sides manually.
In the watch view, check if the CLLLC_vPrimSensed_Volts, CLLLC_iPrimSensed_Amps, CLLLC_vSecSensed_Volts, and CLLLC_iSecSensed_Amps variables are updating periodically. (Note: As no power is applied right now, these will be close to zero.)
Now, slowly increase the input PRIM DC voltage from 0 V to 400 V to soft-start the converter. Make sure CLLLC_vPrimSensed_Volts displays the correct values for VPRIM (that is, close to 400 V).
By default, the CLLLC_pwmPeriodRef_pu variable is set to 0.6, which is 500.8 kHz. This is close to the series resonant frequency of the converter; however, due to variation in the components on the actual hardware, it can be lower or higher than the series resonant frequency.
For the 400-V primary input, with turns ratio being 1.33, the CLLLC_vSecSensed_Volts variable will be close to 300 V. Also, for the load specified in the test conditions, the load will be close to 6.5 A. Set the CLLLC_iSecRef_Amps variable to 6.5 A. If, for some reason, the measured current is different from the 6.5 A, set the Ref close to the measured value. As there is no soft start in the software, it is critical to keep this reference close to the operating point.
Now, set the CLLLC_closeGiLoop variable to 1. This will close the
current loop and the controller will now try to
regulate the current.
Test the closed-loop operation by varying CLLC_iSecRef_Amps from 6.3 A to 6.8 A. The user cannot vary the current too much as a resistive load is connected at the output whose voltage will change with current much more than a battery. This rapid increase in voltage can quickly put the converter in a range that exceeds the controllable range for the fixed VPRIM. Within the small range, the user can see the tracking of the current.