Patent ID: 8880236

Claim:
A control device for an inverter, the control device implementing a model of a synchronous generator comprising: a computer processor; variables representing an angular position and rotational speed of a virtual generator rotor; logic for calculating a virtual electromagnetic torque acting on the virtual generator rotor from measured inverter output current and from a variable representing a virtual excitation current; logic for calculating the rotational speed of the virtual rotor from the virtual electromagnetic torque and from at least one variable representing a virtual drive torque applied to the virtual generator rotor, and from a parameter representing the rotor's virtual inertia; and logic for calculating, from the variables representing angular position and rotational speed of the virtual generator rotor and from the variable representing the excitation current, a control signal for controlling the inverter to produce an AC output which corresponds to that of the virtual synchronous generator, wherein the control device further comprising logic which implements a first feedback loop in which deviation of the rotational speed of the virtual generator rotor from a reference rotational speed is detected and used to adjust the virtual drive torque, thereby to regulate the angular speed of the virtual generator rotor, and hence to regulate frequency of the AC output from the inverter and the real power supplied by the inverter, wherein at least one of said logic for calculating is executed by said computer processor.