A control apparatus for a voltage source converter comprising: a reference voltage generator provided as part of a voltage control loop configured to generate a voltage control signal in a feedforward path extending from the reference voltage generator to a valve of said voltage source converter; and said reference voltage generator is configured to receive at least one feedback signal of DC voltage and/or power and generate the voltage control signal based on said feedback signal and a defined operating set-point, an overcurrent controller configured to generate a current control signal; wherein the overcurrent controller, is located in a control path that is separated and independent from the voltage control loop insofar as the overcurrent controller does not receive the DC voltage, wherein the overcurrent controller is configured to generate the current control signal for modulating the voltage control signal to prevent an overcurrent, overcurrent limiting being applied to the voltage control signal in said feedforward path, the overcurrent controller being further configured to calculate an error between a DC current limit (I DC _lim) and an absolute value of a DC measured current (I DC), and to pass said error through a Proportional-Integral-Derivative controller that is configured to generate a modulating value, the overcurrent controller being configured to multiply said modulating value by the sign of said measured DC current (I DC), such multiplication being employed to give the correct sign of the modulating value depending on the converter operating mode, whether it is a rectifying or an inverting mode, and to further divide the modulating value by two to become the modulating value for each of the valve voltage references. a reference voltage generator provided as part of a voltage control loop configured to generate a voltage control signal in a feedforward path extending from the reference voltage generator to a valve of said voltage source converter; and said reference voltage generator is configured to receive at least one feedback signal of DC voltage and/or power and generate the voltage control signal based on said feedback signal and a defined operating set-point, an overcurrent controller configured to generate a current control signal; wherein the overcurrent controller, is located in a control path that is separated and independent from the voltage control loop insofar as the overcurrent controller does not receive the DC voltage, wherein the overcurrent controller is configured to generate the current control signal for modulating the voltage control signal to prevent an overcurrent, overcurrent limiting being applied to the voltage control signal in said feedforward path, the overcurrent controller being further configured to calculate an error between a DC current limit (I DC _lim) and an absolute value of a DC measured current (I DC), and to pass said error through a Proportional-Integral-Derivative controller that is configured to generate a modulating value, the overcurrent controller being configured to multiply said modulating value by the sign of said measured DC current (I DC), such multiplication being employed to give the correct sign of the modulating value depending on the converter operating mode, whether it is a rectifying or an inverting mode, and to further divide the modulating value by two to become the modulating value for each of the valve voltage references.