Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Method and apparatus for operating an electric vehicle drive system during periods of sensor malfunction
 The present invention provides a protection apparatus in a control system for an electric vehicle which is capable of performing back-up driving by using a back-up control method, without using output from sensors even if the sensor in the control system for ordinary driving is failed. When at least one of the current sensor, the speed sensor and the accelerator sensor is detected to be abnormal, a back-up control voltage v1 is output as an abnormal signal from a running back-up control circuit. As a result, the running back-up control circuit sets the limiter of the output of the current control circuit to zero and switches the control signal to the inverter from vector control to V/f voltage control. 
Hitachi, Ltd. Hitachi Car Engineering Co., Ltd.
B
B60L
inventional
Nobunori Hiroyuki Shigeyuki Sanshiro
Matsudaira Yamada Yoshihara Obara