Thanks. I am going through the PDF and finding it quite helpful. I have a doubt in something mentioned on Pg. 41, could you help me understand it?
"It is worth knowing that if the Vq component is controlled to zero then the Vd component follows the grid-voltage rotation. In this case, the active power injected into the grid may be controlled, transforming the current in the same reference frame and by acting on the amplitude of the Id component. The Iq component must also be controlled in order to ensure zero reactive power injection. On the contrary, if the Vq component is controlled to zero in the PLL, the active power is controlled with the Iq current component and the Id current component is used to control the reactive power to zero or to the desired value."
Something seems quite off in this explanation. If my understanding is right, it should read "On the contrary, if the Vd (not Vq) component is controlled to zero in the PLL, the active power is controlled with the Iq current component and the Id current component is used to control the reactive power to zero or to the desired value"
Could you comment on the need for d-q transformation etc. in the case of Stand-alone loads (for ex. Motors & Resistive banks) In these cases do we need the inverter control specified here, or would there be a simpler way of doing things?