SPECIFICATION OF 10KVA EIGHT PHASED INTER-LEAVED SWITCHING MPPT

Hardware designed by Martin Xavier, software developed by Thomas Jude

Control PCB and one POWER PCB. Control PCB can control up to 4 Power PCBs

Features

DSP based eight phased interleaved switching.

Control device – DSP

Power topology – eight phased interleaved switching

Switching element – MOSFETs

Isolation - No isolation, positive common

Switching frequency in each phase is 18KHz, resultant switching frequency in the final output 144KHz.

Very low ripple current in input and output due to inter-leaved switching.

MCCV battery charger with temperature compensation – Maximum Current Constant Voltage (MCCV) battery charging method. When the battery is discharged or not fully charged, the MPPT action will track the panel impedance and give the maximum current to charge the battery. When the battery voltage is close to full charge voltage, it will reduce the current to keep the battery voltage constant. The current will become zero when the battery voltage is equal or more than the full charge voltage.

Temperature compensated charging -22mv to -30mV per Deg C per battery (settable).

Internal monitoring and recording of data like panel current, panel voltage, battery current, battery voltage is done using RTC and flash memory with year, month, date, day, hour, minute with leap year correction.

Every 55 micro-second the unit will read the data and display on the LCD. Average of these samples will be taken every fifteen minutes which will be used for data logging. Data can be stored up to one year which can be monitored through RS485 / USB.

Protections –

Ø Panel input high voltage – usually the panel voltage should be equal or lesser than the rated voltage of the MPPT. But if accidentally, the connected panel is more voltage than the MPPT’s rated voltage, it will be protected.

Ø Lightning surges at panel input – due to lightning, high voltage spikes coming to the panel input will not cause any damage to the system.

Ø Accidental high current panel connection – usually the panel current and VA should be equal or lesser than the rated current and VA of the MPPT. But if accidentally, the connected panel is more current and more VA than that of MPPT, the MPPT will trip and indicate “Over-rated panel” in the LCD.

Ø Battery full charge cut off

Efficiency – because of inter-leaved switched high efficiency can be achieved, >99%

Total input voltage range: 48V to 220V, Total output voltage range: 40V to 150V

Material cost of 5KVA MPPT solar charger is approx. Rs.8000

Technical know-how cost up to 10KVA is Rs.7 lacs.

A discount of Rs.1 lac is available to all companies that have purchased MEDI’s low power MPPT solar charger up to 48V (old design using micro-controller)