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Abstract Chiral iridium (III) complexes are very important for the preparation of circularly polarized organic diodes light‐emitting diodes (CP‐OLEDs). Three novel iridium (III) complexes, Ir(dnfppy)2(Cl/pyrrole), Ir(dfppy)2(dpp), and Ir(tfmqz)2(sdpp), have been synthesized and characterized, respectively. These iridium (III) complexes emitted deep‐blue, blue, and red photoluminescence with high quantum yields (Ir(dnfppy)2(Cl/Pyrrole): λmax = 447 nm, F = 62.4%; Ir(dfppy)2(dpp): λmax = 467 nm, F = 25%; Ir(tfmqz)2(sdpp): λmax = 609 nm, F = 73.7%). Compared with Ir(dnfppy)2(Cl/pyrrole), the HOMO energy levels of Ir(dfppy)2(dpp) and Ir(tfmqz)2(sdpp) were calculated to be −5.71/−5.73 eV, and the LUMO energy levels were increased to be −2.75/−3.36 eV, respectively. The circular dichroism spectra of two pairs of the enantiomers for Ir(dfppy)2(dpp) or Ir(tfmqz)2(sdpp) displayed symmetry with opposite polarization between 300 and 600 nm. The maximum external quantum efficiency (EQEmax) of OLEDs based on Ir(tfmpqz)2(sddp) was 13.8%, showing a relatively low efficiency roll‐off with the EQE of 10.7% at 5000 cd/m2.

Abstract Electro‐mechanical actuators with redundancy design use a cross‐coupling control strategy to enhance the coordinated control capability of the aviation motors. Due to its linear control characteristic, traditional cross‐coupling control reveals moderate dynamic response performance and synchronisation control accuracy. To further reduce the susceptibility to load torque and parameter perturbations in the application of a dual permanent magnet synchronous motor system, this paper proposes a non‐linear active disturbance rejection control (ADRC)‐based synchronisation control strategy. Considering the low gain problem of traditional ADRC when the speed tracking error is large, a non‐linear ADRC speed controller with an efal function is designed. Meanwhile, a Levant differentiator is proposed to improve the speed tracking performance during dynamic processes. Moreover, a non‐linear synchronous controller with current constraints is applied to the cross‐coupling control to enhance the synchronisation convergence performance of the dual‐PMSM system. Finally, simulation and experimental results demonstrate the effectiveness of the proposed non‐linear ADRC speed synchronisation control.

Abstract The utilization of novel cascode GaN devices can significantly increase the power density and the efficiency of convertors. However, owing to high switching speed (high dv/dt or di/dt) and inevitable parasitic inductance in device packages and external circuits, cascode GaN devices are more prone to oscillate, resulting in voltage overshoot, electromagnetic interference (EMI), and even device breakdown, which reduces the reliability of the drive system. Therefore, effective suppression of the switching oscillation becomes highly critical. This paper presents an integrated modelling and a parameter design method for cascode GaN‐based bridge convertors. Firstly, a high‐frequency equivalent circuit model is derived for the switching oscillation of cascode GaN‐based bridge convertors. Secondly, a quantitative RC snubber parameter design method is established based on root locus analysis, which makes up for defects of the previous trial‐and‐error empirical method. Then impacts of the RC snubber on power loss and EMI are also studied, with the optimal snubber resistance and capacitance obtained by minimizing power loss. Finally, the effect of oscillation suppression is verified by simulation and experiment, and results show good agreement with the theoretical analysis.