Hello
I have developed a Solar driven Pump and am having a bit of a trouble in tuning the whole thing.
The algorithm works in 3 blocks
1) Sine PWM generation for driving Power MOSFETS : 6 PWM pulses sine weighted
2) MPPT using Solar voltage and current : Gets wattage and determines max power point
3)Variable frequency : to maintain constant V/F ratio on pump motor
I am observing that a small cloud cover in the sky renders the circuit dead and unusable. Whereas a healthy solar insolation guarantees optimum withdrawal of water.
Same thing happens in the evening.
I am powering the Microcontroller and the driver for MOSFETS through a branch of the 700Vdc panel. 400Vdc to be precise which powers an SMPS to get 15V for entire circuit
Whenever a cloud shadow falls on the PV panels, the MPPT starts acting and increases duty and so the panel voltage reduces.
But once it drops below minimum required input SMPS voltage, the circuit restarts (SMPS off and on)
I have a soft start implemented as well , which increases the frequency 1 Hz at a time for 20 seconds after which the V/F ratio comes in picture. So in the evening when it is starting, i see water being drawn, but as soon as it quits Soft start and enters dynamic V/F ratio maintaining, the Panel voltage drops quite rapidly by increasing duty (since the algorithm is not able to determine the Max power yet)
I have checked my MPPT algorithm and i find that satisfactory.
So i am stuck here...Can someone help me?
Thanks in advance
I have developed a Solar driven Pump and am having a bit of a trouble in tuning the whole thing.
The algorithm works in 3 blocks
1) Sine PWM generation for driving Power MOSFETS : 6 PWM pulses sine weighted
2) MPPT using Solar voltage and current : Gets wattage and determines max power point
3)Variable frequency : to maintain constant V/F ratio on pump motor
I am observing that a small cloud cover in the sky renders the circuit dead and unusable. Whereas a healthy solar insolation guarantees optimum withdrawal of water.
Same thing happens in the evening.
I am powering the Microcontroller and the driver for MOSFETS through a branch of the 700Vdc panel. 400Vdc to be precise which powers an SMPS to get 15V for entire circuit
Whenever a cloud shadow falls on the PV panels, the MPPT starts acting and increases duty and so the panel voltage reduces.
But once it drops below minimum required input SMPS voltage, the circuit restarts (SMPS off and on)
I have a soft start implemented as well , which increases the frequency 1 Hz at a time for 20 seconds after which the V/F ratio comes in picture. So in the evening when it is starting, i see water being drawn, but as soon as it quits Soft start and enters dynamic V/F ratio maintaining, the Panel voltage drops quite rapidly by increasing duty (since the algorithm is not able to determine the Max power yet)
I have checked my MPPT algorithm and i find that satisfactory.
So i am stuck here...Can someone help me?
Thanks in advance