A Hybrid Diagnosis Method for Inverter Open-circuit Faults in PMSM Drives

In order to improve the evaluation process of inverter open-circuit faults diagnosis in permanent magnet synchronous motor(PMSM)drives,this paper presents a diagnosis method based on current residuals and machine learning models.The machine learning models are introduced to make a comprehensive evaluation for the current residuals obtained from a state observer,instead of evaluating the residuals by comparing with thresholds.Meanwhile,fault diagnosis and location are conducted simultaneously by the machine learning models,which simplifies the diagnosis process.Besides,a sampling strategy is designed to implement the proposed scheme online.Experiments are carried out on a DSP based PMSM drive,and the effectiveness of the proposed method is verified.

Switching Behavior of Cascode GaN Under Influence of Gate Driver

With high-frequency,low power dissipation and high-efficiency characteristics,Gallium nitride(GaN)power devices are of significant benefit in designing high-speed motor drives,as they improve performance and reduce weight.However,due to the cascode structure,coupling with the parasitics in gate driver and power circuits,power converters based on cascode GaN are prone to overshoot and oscillate on switching waveforms,which may lead to serious EMC problems,or even device breakdown.The complicated structure of cascode GaN device makes the gate driver design comparatively complex.An analytical model of the switching process considering gate driver parameters is proposed in this article.The influence of gate driver parameters on switching behavior is investigated from the perspective of switching speed,waveform overshoot,and power loss.Trade-offs among overshoot,switching speed,and power loss are discussed;guidelines to design gate driver parameters are given.

A linear ADRC-based robust high-dynamic double-loop servo system for aircraft electro-mechanical actuators

Compared with traditional hydraulic actuators, an Electro-Mechanical Actuator(EMA)is small in size and light in weight, so it has become more widely used. Aerodynamic load on aircraft control surface varies dramatically, and a change of flight environment leads to uncertainties of motor parameters. Therefore, high-dynamic response and strong anti-disturbance capability of an EMA are of great significance for aircraft rudder control and flight attitude adjustment. In order to improve dynamic response and disturbance rejection of an EMA and simplify control parameters tuning, a robust high-dynamic servo system based on Linear Active Disturbance Rejection Control(LADRC) is proposed for an EMA employing a Permanent Magnet Synchronous Motor(PMSM).Firstly, total disturbances of the EMA are analyzed, including parameter uncertainties, load variation, and static friction. A disturbance observer based on a reduced-order Extended State Observer(ESO) is designed to improve the anti-interference ability and dynamic performance. Secondly, the servo control architecture is simplified to a double-loop system, and a composite control of position and speed with acceleration feed-forward is presented to improve the EMA frequency bandwidth.Thirdly, the ideal model of the EMA is transformed into a simple cascade integral form with a disturbance observer, which makes it convenient to analyze and design the controller. Robustness performance comparisons are realized in frequency domain. Finally, simulation and experimental results have verified the effectiveness of the proposed strategy for EMAs.