Gilbert Foo Hock Beng

Sensor Fault-Resilient Control of Interior Permanent-Magnet Synchronous Motor Drives

In a conventional ac motor drive using field-oriented control, a dc-link voltage, speed, and at least two current sensors are required. Hence, in the event of sensor failure, the performance of the drive system can be severely compromised. This paper presents a sensor fault-tolerant control strategy for interior permanent-magnet synchronous motor (IPMSM) drives. Three independent observers are proposed to estimate the speed, dc-link voltage, and currents of the machine. If a sensor fault is detected, the drive system isolates the faulty sensor while retaining the remaining functional ones. The signal is then acquired from the corresponding observer in order to maintain the operation of the drive system. The experimental results provided verify the effectiveness of the proposed approach.

A modified hysteresis-based DTC strategy for synchronous reluctance motors in high speed range

This paper presents a modified hysteresis-based direct torque control (DTC) for synchronous reluctance machines. The proposed method is utilized to achieve high torque capability in flux weakening region. It will be shown that hysteresis-based DTC is established by two hysteresis comparators. A higher torque capability is fulfilled by switching only the optimized voltage vector during torque dynamic condition, instead of alternating between two vectors. The selection of optimized voltage vector can be implemented by modifying the flux error status generated by the stator flux comparator before it is fed to the switching table. The main benefit of the proposed method is its simplicity because it requires only a minor modification to conventional hysteresis-based DTC and does not require a space vector block. The effectiveness is verified by simulation.

Soft-switching single inductor current-fed push-pull converter for PV applications

A switching control strategy is proposed for single inductor current-fed push-pull converter with a secondary side active voltage doubler rectifier or a voltage rectifier used in photovoltaic (PV) grid interfacing. The proposed switching control strategy helps to turn-on and turn-off the primary side power switches with zero-voltage and zero-current switching. The operation of the push-pull converter is analyzed for two modes of operation. The feasibility of the proposed switching control strategy is validated using simulation and experimental results.