A new resonant DC link/boost converter topology applied to extended speed operation of a brushless DC machine

Although the brushless DC machine (BDCM) is a strong contender for use in an electric vehicle (EV) drive system due to its size and efficiency, it has one major drawback; its maximum speed is restricted such that the back EMF is always less than or equal to the battery voltage. This paper presents the use of the well established actively clamped resonant DC link inverter (ACRLI) to control a BDCM in an EV, with a modification to allow boost operation. With the addition of one diode and one switch the average output voltage of the converter can be boosted. A hard-switched current control method is presented in this paper which allows full regenerative operation of the BDCM in both normal and boosted modes.