This paper presents the design and experimental results of the first chip-scale radio frequency MEMS gyrator based on hybridizing Lorentz-force and piezoelectric transduction. The MEMS gyrator has a non-reciprocal phase response of 180° and can be used as the building blocks for synthesizing complex non-reciprocal networks. The equivalent circuit and measured performance of a fabricated MEMS gyrator are presented, both showing the anticipated 180° phase difference. The demonstration marks the first time that non-reciprocity is attained at radio frequencies with an entirely passive chip-scale mechanical device. Various challenges in achieving strong coupling and low insertion loss for the designed devices will be discussed.

@en

This paper investigates SiC power semiconductor devices in a three-phase active front-end Boost PWM rectifier for power conversion efficiency improvement. Different from Si IGBT based Boost PFC rectifier, the SiC MOSFET based Boost PFC rectifier can achieve the synchronous rectification by MOSFET channel reverse conduction for efficiency improvement. The operation principle difference of three-phase active frontend Boost PWM rectifier with SiC MOSFET and Si IGBT is introduced. The switching characterizations of 1.2kV SiC MOSFET are provided. 5kW 380VAC input, 800VDC output three-phase active front-end Boost PWM rectifier prototype is built in lab to evaluate the efficiency advantage with SiC device. All SiC power semiconductor devices based circuit achieves about 1.2% more efficient compared with all Si devices, and around 0.5% more efficient than Si IGBT & SiC diode hybrid device pair for the three-phase Boost PWM rectifier due to low switching loss of 1.2kV SiC MOSFET and reduced conduction loss from the synchronous rectification operation for 1.2kV SiC MOSFET.@en