Development of inverter simulation system and its applications for hybrid vehicles

This article describes an electro-thermal-mechanical coupled simulation newly developed for HV inverters, a modeling technique for fast and accurate calculation, simulation results, several applications and their verifications. The model is based on an electric circuit simulation technique and is obtained by modeling a motor, motor controller, power semiconductor devices and their driver circuits, interconnection, smoothing capacitors, and thermal circuits of power semiconductors including package structure. The current, voltage, and carrier frequency data computed from the control system model containing many dynamic characteristics of motor and vehicle specifications as driving conditions were inputted into the inverter circuit. Using this modeling technique, a five-second full-throttle simulation was completed in sixteen hours of computation time because of the model parameter determined by the effect of acceleration performance. This inverter system model enables simulations with various characteristics from all inverter components, such as the controller, the silicon chip, device packages, cooling structure and driver circuits. The error in the simulation is below five percent. This technique enables not only simulation of single components but also of the mutual impact among several components in an inverter system. As a result, the inverter design could be optimized, thus contributing to significant improvements in the high acceleration performance of HVs.