Reivindicaciones

1. Method for controlling the voltage and frequency in an isolated grid comprising a busbar (5) that receives energy from at least one wind-driven power generator (1) and outputs same by means of a rectifier (2) towards a DC transmission link (4), the busbar (5) being connected to a capacitor bank (6), wherein said method comprises the step of keeping the direct component d (9) and quadrature component q (10) of the voltage vector (11) in the busbar (5) constant in order to keep the magnitude and frequency of the voltage in the busbar (5) constant, respectively, characterized in that : - the quadrature component q (10) of the voltage vector (11) is kept constant by regulating the reactive current injected into the busbar (5), - when the rectifier (2) is an uncontrolled diode rectifier, the direct component d (9) of the voltage vector (11) is automatically regulated in a passive manner, a specific value of the AC voltage being established starting from an established DC voltage, and - when the rectifier (2) is a controlled thyristor rectifier, the direct component d (9) of the voltage vector (11) is kept constant by controlling the firing angle (8) of the thyristors so that said rectifier (2) absorbs all the active power generated by the wind-driven power generator (1). 2. Method according to claim 1, wherein control over the reactive current injected into the busbar (5) is performed by means of regulating the reactive power generated by the wind-driven power generator (1). 3. Method according to claim 1, wherein control over the reactive current injected into the busbar (5) is performed by means of a reactive power regulation device connected to said busbar (5). 4. Method according to claim 3, wherein the reactive power regulation device is an SVC or a STATCOM. 5. Method according to any of the preceding claims, wherein control over the firing angle (8) of the thyristors of the rectifier (2) is performed directly or indirectly by means of a subordinate control loop.