Power generation system and controller for power generation system

A power generation system, comprising:

• a prime mover;
• a magnetic gear generator configured to be driven by an input from the prime mover to generate power;
• a power converter connected to the magnetic gear generator;
• an operation mode switch unit configured to switch an operation mode of the magnetic gear generator to a step-out avoidance mode in response to that a step-out parameter indicating a risk of step-out of the magnetic gear generator exceeds a prescribed allowable range;
• and
• a reduction command unit configured to give the prime mover an input reduction command to reduce the input from the prime mover and configured to give the power converter a torque reduction command to reduce a generator torque of the magnetic gear generator, in the step-out avoidance mode, wherein
• the magnetic gear generator includes:
• a low-speed rotor configured to be driven by an input torque from the prime mover;
• a high-speed rotor configured to be driven by a magnetic torque generated as the low-speed rotor rotates;
• and
• a stator with a stator winding configured to generate supply power to the power converter as the high-speed rotor rotates, and
• the reduction command unit is configured to give the torque reduction command to the power converter such that an amount of variation in the generator torque is proportional to an amount of variation in angular acceleration of the high-speed rotor with reference to a reference state in which the step-out parameter is included within the allowable range.

A power generation system, comprising:

• a prime mover;
• a magnetic gear generator configured to be driven by an input from the prime mover to generate power;
• a power converter connected to the magnetic gear generator;
• an operation mode switch unit configured to switch an operation mode of the magnetic gear generator to a step-out avoidance mode in response to that a step-out parameter indicating a risk of step-out of the magnetic gear generator exceeds a prescribed allowable range;
• and
• a reduction command unit configured to give the prime mover an input reduction command to reduce the input from the prime mover and configured to give the power converter a torque reduction command to reduce a generator torque of the magnetic gear generator, in the step-out avoidance mode, wherein
• the prime mover is a renewable energy extraction apparatus configured to extract renewable energy to generate the input to the magnetic gear generator,
• the reduction command unit is configured to give the input reduction command to the renewable energy extraction apparatus to decrease an extraction amount of the renewable energy regardless of whether the step-out parameter exceeds the allowable range if a future predicted value of the renewable energy is greater than an upper limit value,
• the renewable energy extraction apparatus includes:
• an energy extraction part configured to extract the renewable energy;
• a prime mover rotor configured to be driven by the extracted renewable energy;
• and
• a control device configured to give a control command to the energy extraction part such that a rotation speed of the prime mover rotor approaches a target rotation speed, and
• the reduction command unit is configured to:
• give the control device a command to reduce the target rotation speed as the input reduction command, when the step-out parameter exceeds the allowable range if the future predicted value of the renewable energy is not greater than the upper limit value;
• and
• give the input reduction command to the energy extraction part to decrease the extraction amount of the renewable energy, without via the control device, if the future predicted value of the renewable energy is greater than the upper limit value.

A controller for a power generation system, comprising:

• an operation mode switch unit configured to switch an operation mode of a magnetic gear generator to a step-out avoidance mode in response to that a step-out parameter indicating a risk of step-out of the magnetic gear generator exceeds a prescribed allowable range, the magnetic gear generator being configured to be driven by an input from a prime mover to generate power;
• and
• a reduction command unit configured to give the prime mover an input reduction command to reduce the input from the prime mover and configured to give a power converter connected to the magnetic gear generator a torque reduction command to reduce a generator torque of the magnetic gear generator, in the step-out avoidance mode, wherein
• the magnetic gear generator includes:
• a low-speed rotor configured to be driven by an input torque from the prime mover;
• a high-speed rotor configured to be driven by a magnetic torque generated as the low-speed rotor rotates;
• and
• a stator with a stator winding configured to generate supply power to the power converter as the high-speed rotor rotates, and
• the reduction command unit is configured to give the torque reduction command to the power converter such that an amount of variation in the generator torque of the high-speed rotor is proportional to an amount of variation in the input torque of the low-speed rotor with reference to a reference state in which the step-out parameter is included within the allowable range.

A controller for a power generation system, comprising:

• an operation mode switch unit configured to switch an operation mode of a magnetic gear generator to a step-out avoidance mode in response to that a step-out parameter indicating a risk of step-out of the magnetic gear generator exceeds a prescribed allowable range, the magnetic gear generator being configured to be driven by an input from a prime mover to generate power;
• and
• a reduction command unit configured to give the prime mover an input reduction command to reduce the input from the prime mover and configured to give a power converter connected to the magnetic gear generator a torque reduction command to reduce a generator torque of the magnetic gear generator, in the step-out avoidance mode, wherein
• the magnetic gear generator includes:
• a low-speed rotor configured to be driven by an input torque from the prime mover;
• a high-speed rotor configured to be driven by a magnetic torque generated as the low-speed rotor rotates;
• and
• a stator with a stator winding configured to generate supply power to the power converter as the high-speed rotor rotates, and
• the reduction command unit is configured to give the torque reduction command to the power converter such that an amount of variation in the generator torque is proportional to an amount of variation in angular acceleration of the high-speed rotor with reference to a reference state in which the step-out parameter is included within the allowable range.

A controller for a power generation system, comprising:

• an operation mode switch unit configured to switch an operation mode of a magnetic gear generator to a step-out avoidance mode in response to that a step-out parameter indicating a risk of step-out of the magnetic gear generator exceeds a prescribed allowable range, the magnetic gear generator being configured to be driven by an input from a prime mover to generate power;
• and
• a reduction command unit configured to give the prime mover an input reduction command to reduce the input from the prime mover and configured to give a power converter connected to the magnetic gear generator a torque reduction command to reduce a generator torque of the magnetic gear generator, in the step-out avoidance mode, wherein
• the prime mover is a renewable energy extraction apparatus configured to extract renewable energy to generate the input to the magnetic gear generator,
• the reduction command unit is configured to give the input reduction command to the renewable energy extraction apparatus to decrease an extraction amount of the renewable energy regardless of whether the step-out parameter exceeds the allowable range if a future predicted value of the renewable energy is greater than an upper limit value,
• the renewable energy extraction apparatus includes:
• an energy extraction part configured to extract the renewable energy;
• a prime mover rotor configured to be driven by the extracted renewable energy;
• and
• a control device configured to give a control command to the energy extraction part such that a rotation speed of the prime mover rotor approaches a target rotation speed, and
• the reduction command unit is configured to:
• give the control device a command to reduce the target rotation speed as the input reduction command, when the step-out parameter exceeds the allowable range if the future predicted value of the renewable energy is not greater than the upper limit value;
• and
• give the input reduction command to the energy extraction part to decrease the extraction amount of the renewable energy, without via the control device, if the future predicted value of the renewable energy is greater than the upper limit value.