考虑双馈异步发电机转速限制的电网频率协调控制策略

Coordinated grid frequency control strategy of doubly-fed induction generator considering its rotor speed constraints

双馈异步发电机(DFIG)参与惯性调频能减小频率变化率,一次调频能减小稳态频率偏差。为解决上述两种策略协调控制过程中因频率偏差和微分系数选择而易导致异步发电机转子转速越限的问题,提出一种考虑转速限制的电网频率协调控制策略。通过控制DFIG的输出功率,确保转速偏差和频率偏差成正比。以转子转速为约束,整定频率信号的比例系数。根据电网频率变化情况,调整输出功率参考值,使得转速保持恒定,且有利于频率的恢复。仿真结果验证了所提策略能有效防止转子转速越限,有助于提高系统频率的稳定性。

The doubly-fed induction generator （DFIG） participating in inertia and primary frequency regulation can reduce the rate of change of frequency and steady state frequency deviation respectively. A coordinated grid frequency control strategy considering its rotor speed constraints is proposed to solve the problem that the rotor speed is easy to exceed its constraints due to the frequency deviation and differential coefficients selection when coordinating the aforementioned two frequency control strategies. Controlling the DFIG output power can ensure that the rotor speed deviation is proportional to the frequency deviation. The coefficients of frequency signal are set based on the rotor speed constraints. According to the change of grid frequency, the output power reference value is adjusted to ensure constant rotor speed and assist the frequency recovery. Simulation results verify that the proposed control strategy can effectively keep the rotor speed within its limits and enhance the system frequency stability.