A Novel Local Voltage Sensing Mode for High Voltage IGBT Sensor

Collector-emitter voltage (
V
_ce
) detection of insulated gate bipolar transistors (IGBTs) is important for safety-critical and mission-critical power applications. The conventional voltage sensing method is characterized by the detection range from 0 V to the rated voltage in the application (
V
_r
), which is limited by the contradiction between the dynamic range of the signal and the ADC resolution in high voltage situations. This letter proposes a novel local voltage sensing (LVS) mode, in which the detection range is from
V
_st
to
V
_r
, where
V
_st
is a controllable starting point for the sensed voltage. Based on the LVS mode, a novel controllable voltage sensor structure is given, which can provide a sensing signal that is a scaled version of the large
V
_ce
when
V
_ce
≥
V
_st
.
V
_st
can be controlled by applying a negative voltage to a control electrode gate (
V
_G2
). An analytical model is derived to understand the mechanism of the sensor and simplify the design. The effects of internal and external parameters on the sensing characteristics are simulated using Medici & TS4. Furthermore, the sensor is incorporated into a prototype 1200-V IGBT. The test results show that, under the condition of
V
_G2
= 0 V or
V
_G2
= −1 V,
V
_st
and nonlinear error are 622 V and 3.9% or 708 V and 3.4%, respectively, and the experimental data agree with the analytical model results. Finally, an application of dc-bus voltage monitoring using the LVS mode is presented.