参考跟踪和扰动抑制解耦的双三相永磁同步电机容错控制策略

An Fault-Tolerant Control Strategy Based on Decoupling between Reference Tracking and Periodic Disturbance Attenuation for Dual-Three-Phase Permanent Magnet Synchronous Machine

双三相永磁同步电机发生断相故障时,转速及电流中将会出现明显的周期性扰动。为了解决这一问题,该文提出了一种容错控制器,该控制器包含基于主控制器的参考值跟踪环路和基于重复控制器的周期性扰动抑制环路。所提出的容错控制器不仅可以实现对周期性扰动的闭环抑制,有效降低断相故障后系统中的转速脉动和谐波电流,还能够实现系统参考值追踪与周期性扰动抑制之间的解耦,避免重复控制器对暂态性能的影响。将所提出的控制器分别应用于驱动系统的转速环和电流环中,实验结果表明,与传统策略相比,该容错控制策略不仅能够有效抑制周期性扰动,还拥有更快更平稳的暂态跟踪响应。

Under open-phase fault conditions,the dual three-phase permanent magnet synchronous machine(DT-PMSM)suffers from periodic disturbances,which may cause significant performance degradation.Therefore,it is regarded as a major concerno of fault-tolerant control.The feed-forward compensation method is widely used under postfault situation to suppress periodic disturbances.However,the effect of disturbance suppression can be easily affected by non-ideal factors,such as parameter variation,inverter dead-time,cogging torque,and flux harmonic of permanent magnet.In order to solve this problem,the proportional resonance(PR)controller is paralleled to the original proportional integral(PI)controller in some references.The closed-loop control structure can effectively suppress the periodic disturbances without being affected by non-ideal factors.However,the coupling effects between reference tracking and periodic disturbance attenuation will lead to significant transient oscillations under the situation of a reference step change.In order to realize decoupling between reference tracking and disturbance attenuation,this paper proposes a novel fault-tolerant controller which contains two independent control loops.The reference tracking is only determined by the primary controller,and the disturbance rejection loop is embedded to achieve periodic disturbance attenuation.Firstly,the PI controller outputs the initial reference value,while the extended state observer(ESO)predicts the system output value based on the initial reference value.Then,the error signal between the predicted value and actual value is input to resonant controller.Finally,the initial reference value and output signal of resonant controller are added to obtain the final reference value.The main transfer function of the proposed controller is consistent with that of the feed-forward compensation controller,and the resonant controller only responds to periodic disturbances.With the proposed controller adopted,periodic disturbances are strongly attenuated while smooth and fast transient performances are simultaneously guaranteed.The performances of different controllers are compared experimentally in this paper.Firstly,when the speed is 1000r/min and load torque is 5N·m,the steady-state performances are compared under open-phase fault condition.With the feed-forward compensation controller,parallel controller,and the proposed controller adopted,the total harmonic distortion(THD)of phase current is 11.86%,9.07%,and 8.81%,respectively.The speed fluctuation is 19.7r/min,12.2r/min,and 11.3r/min,respectively.And the torque fluctuation is 1.15N·m,0.9N·m,and 0.84N·m,respectively.From the above experimental results,it can be seen that the steady-state performance of the proposed controller is obviously better than that of the feed-forward compensation method.The transient experiments are also carried out in this paper.When the speed reference is step changed from 100r/min to 200r/min,the transient responses are compared.With the feed-forward compensation controller,parallel controller,and the proposed controller adopted,the speed fluctuation is 25.1r/min,74.6r/min,and 9.5r/min,respectively.The adjustment time is 0.1s,0.13s,and 0.06s,respectively.When the reference value of iq is step changed from 2A to 5A,the transient responses are compared.The iq fluctuation is 0.95A,1.12A,and 0.44A,respectively.The adjustment time is 10ms,36ms,and 6ms,respectively.The experimental results prove the efficiency of the proposed method.The reference tracking loop and periodic disturbance suppression loop are decoupled.The proposed fault-tolerant controller improves the transient performance and steady-state performance simultaneously.