Power converter control and operation

A method of operating a wind turbine having a generator and a power converter, the method comprising:

• in a normal operating state, supplying active power from the generator to an electrical grid through a power converter having a line-side converter and a machine-side converter;
• in response to an operational grid condition, determining a first power setpoint for control of the line-side converter to reduce active power supplied from the line side converter to the electrical grid as compared to the active power from the generator to the machine-side converter;
• controlling the first power setpoint to reduce the active power from the line-side converter to the electrical grid at a first reduction rate;
• at a same time as determining the first power setpoint, determining a second power setpoint for control of the machine-side converter such that a torque applied to the generator by the machine-side converter reduces the active power from the generator and maintains the active power from the generator greater than the active power from the line-side converter to the electrical grid;
• controlling the second power setpoint to reduce the active power from the generator at a second reduction rate that is less than the first reduction rate, wherein the active power from the generator reduces at the second reduction rate and remains greater than the active power from the line-side converter to the electrical grid as the active power from the line-side converter reduces at the first reduction rate;
• and
• dissipating an active power surplus between the active power from the generator and the active power from the line-side converter to the electrical grid in one or more resistive elements as long as the second power setpoint is greater than the first power setpoint.