Not sure if you understand MPPT, otherwise what's the problem?
There are two requisites for MPPT implementation:
- an inverter with variable DC input voltage, e.g. 120 - 150 V as specified in post #1
- a MPPT control algorithm varying the inverter voltage ratio continuously to achieve maximum output power for the respective solar irradiation level.
The inverter voltage ratio is the ratio between a DC input and a sine output voltage. In so far the MPPT controller output isn't directly setting the PSB duty cycle, it's setting the magnitude of a sine modulator. In a grid-tied inverter implementation, it's more suitable to set a sinusoidal output current than a voltage.