| 초록 |
The 2-Stage motor system is a technology that can enhance the performance of electric vehicles by increasing the power through the use of an open-end winding motor and a dual inverter system. It helps increase the available voltage size of the motor based on the same battery voltage standard. 2-Stage refers to two driving modes, and it allows the use of closed-end winding (CEW) mode and open-end winding (OEW) mode in one motor system using a switching switch. However, when the mode is switched, the available voltage ellipse size changes rapidly by about 1.7 times. This causes a significant change in the d-axis and q-axis current commands in the control area of the Interior permanent-magnet synchronous motor (IPMSM). As a result, torque ripple can occur in the vehicle during mode switching, which can significantly degrade vehicle speed and driving quality, and act as a factor of instability in mode switching. In this paper, variable modulation index control logic is proposed to prevent torque shock during switching. The logic was developed to prevent the rapid change in current command caused by the inverter's available voltage difference in the CEW ↔ OEW switching boundary area. In this study, we proposed linear logic that can linearize the changes in the reference value of the voltage utilization ratio that determines the size of the voltage limit ellipse. It was confirmed that the available voltage change in the switching area can be linearized, and the current change, torque shock, and ripple were greatly improved. It is expected that the use of this control algorithm will alleviate the switching shock of the 2-Stage motor system, thereby improving the driving quality of the EV powertrain. |
