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In hybrid and electric vehicles, the control of the electric motor is a critical component of vehicle functions such as motoring, generating, engine-starting and braking. The efficient and accurate control of motor torque is performed by the motor controller. It is a complex system incorporating sensor sampling, data processing, controls, diagnostics, and 3-phase Pulse Width Modulation (PWM) generation which are executed in sub-100 uSec periods. Due to the fast execution rates, care must be taken in the software coding phase to ensure the algorithms will not exceed the target processor's throughput capability. Production motor control development often still follows the path of customer requirements, component requirements, simulation, hand-code, and verification test due to the concern for processor throughput. In the case of vehicle system controls, typically executed no faster than 5-10 mSec periods, auto-coding tools are used for algorithm development as well as testing.

A complete system approach to power semiconductor analysis and selection is set forth in this paper. In order to address design overkill, a suitable power profile across the desired drive schedule is obtained through vehicle simulation in lieu of worse case operating conditions. The representative profile is then applied to detailed models of the inverter, power device, and power device thermal stack-up in order to predict worse case, silicon junction temperature rise. The simulation stream includes a closed silicon thermal loop that leads to more accurate power loss and junction temperature calculations. The models are combined and exercised in a single platform for ease of integration and fast simulation. Herein, the methods will be applied to a working example of an inverter for motor drives, and analytical results will be reviewed.

This paper presents a monitoring, feedback and control system for SCR urea dosing utilizing an embedded model and NH3 sensing after the SCR for loop closing control. A one-dimensional SCR model was developed and embedded in a Simulink/Matlab environment. This embedded model is utilized for on-line, real time control of 32.5% aqueous urea dosing in the exhaust stream. Engine testing and simulation are used with the embedded SCR model and NH3 sensor closed loop feedback to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. The paper explores these advantages under heavy duty FTP cycle conditions. The potential benefits include SCR size optimization and fuel consumption rate reduction under certain operating conditions.