• Energy Research

Interior permanent-magnet synchronous motors (IPMSMs) become attractive candidates in modern hybrid electric vehicles and industrial applications. Usually, to obtain good control performance, the electric drives of this kind of motor require one position, one dc link, and at least two current sensors. Failure of any of these sensors might lead to degraded system performance or even instability. As such, sensor fault resilient control becomes a very important issue in modern drive systems. This paper proposes a novel sensor fault detection and isolation algorithm based on an extended Kalman filter. It is robust to system random noise and efficient in real-time implementation. Moreover, the proposed algorithm is compact and can detect and isolate all the sensor faults for IPMSM drives. Thorough theoretical analysis is provided, and the effectiveness of the proposed approach is proven by extensive experimental results.

The optimal sizing of the unified power quality conditioner (UPQC) system has been investigated in this paper. The optimal VA ratings of the transformer and series/shunt converter of the UPQC system are designed by a two-level algorithm. The UPQC-P and UPQC-VAmin based systems are chosen as the benchmarks in this paper. Furthermore, the displacement angle control (DAC) is utilized to minimize the overall VA loading of the power converters for all operational points. Finally, the corresponding controllers are developed for the designed systems.

This paper presents an improved field weakening (FW) algorithm for synchronous-reluctance-motor drives. The proposed algorithm is robust to the variations in the machine $d$ - and $q$ -axis inductances. The transition between the maximum torque per ampere, current and voltage limits, and the maximum torque per flux trajectories is smooth. The proposed technique is combined with the direct-torque-control method to attain a high performance drive in the FW region. Simulation and experimental results are supplemented to verify the effectiveness of the proposed approach.

This paper introduces a novel sliding mode controller to regulate frequency within a decentralized control framework. The decentralized frequency regulation model is a continuous-time linear system with mismatch disturbance that cannot be effectively removed. The proposed method combines the sliding mode and active disturbance rejection theories to reject the effects of mismatched disturbances with the aid of a disturbance observer to achieve a fully decentralized frequency regulation control. Furthermore, the sliding variables can be directly computed using the proposed steady-state method. In addition, by incorporating a constant delay into the input of the sliding mode controller, the transient performance is improved, resulting in a smaller overshoot and a shorter response time. Specifically, the proposed method demonstrated enhancements over the liner active disturbance rejection algorithm (5.04% and 54.4%, respectively), conventional proportional integral derivative method (5.09% and 68.03%, respectively), disturbance observer–based integral sliding mode control method (6.59% and 84.34%, respectively), and disturbance observer–based adaptive integral sliding mode control method (5.93% and 82.47%) in terms of both overshoot and response time.

Induction motors (IMs) have been extensively used in industrial applications because of their inexpensiveness, ruggedness and reliability. Generally, to improve the performance of IM drives, one position sensor, one DC-link voltage sensor and at least two AC current sensors are necessary. However, failure of any of these sensors can cause degraded system performance or even instability. Consequently, it is very important to develop a sensor fault resilient control system for IMs drives so that continuous and normal operation is maintained even in cases of sensor faults. This study proposes a compact and robust sensor fault detection, isolation and system reconfiguration algorithm based on extended Kalman filter and reduced number of adaptive observers. A comprehensive set of experimental results are provided to verify the effectiveness of the proposed algorithm.