State of health (SOH) estimation of multiple switching devices using a single intelligent gate driver module

摘要

This paper presents a new platform for intelligent gate-driver architecture that enables real-time health monitoring of power devices while performing features offered by a commercially available driver. The novelty of this new technique is the application of spread spectrum time domain reflectometry (SSTDR) embedded pulse width modulated (PWM) sequence across the gate and the source of a power MOSFET. A degraded MOSFET experiences an increase in both ON-state channel resistance and equivalent series resistance of gate-source capacitance, and the SSTDR sequence can characterize the level of aging in a live circuit based on these impedance variations. To validate our proposed method, the SSTDR incident signal was applied across the high side MOSFET of a synchronous buck converter, and corresponding reflections were recorded and analyzed. Extensive variation in impedances throughout the circuit using PWM switching scheme makes the degradation detection more challenging. However, a new algorithm has been introduced in this paper to solve the problem mentioned above. Included experimental results demonstrate that the developed method can perform online degradation monitoring of multiple devices from a single measurement point, which will eliminate the need of a separate state of health (SOH) monitoring module for detecting degradation in each device. Although the initial test results are obtained for power MOSFETs, the proposed technique is equally applicable to other power devices such as IGBTs and silicon carbide (SiC) MOSFETs.