Hybrid DC-Bus Capacitor Discharge Strategy Using Internal Windings and External Bleeder for Surface-mounted PMSM based EV Powertrains in Emergency

Chao Gong, Yihua Hu, Wenzhen Li, Jinqiu Gao, Jinglin Liu, Huiqing Wen, Jiankang Yang

Research output: Contribution to journalArticlepeer-review


When electric vehicles (EVs) encounter an
emergency, the voltage of the DC-bus capacitor in the
surface-mounted permanent magnet synchronous motor
(SPMSM) based powertrain requires to be reduced as fast
as possible. In order to eliminate the disadvantages and
synthesize the advantages of the traditional machine
winding-based and external bleeder-based discharge
techniques, this paper proposes a hybrid discharge
strategy which can achieve five-second discharge in
minimum sacrifice of the bleeder size and weight for any
EV drives. For the purpose of evaluating the size reduction
of the new method, the individual bleeder-based scheme is
modelled and analyzed at first. Then, the combined
discharge method is developed, which contains two
sequential procedures: bleeding resistor (BR) design and
discharge control algorithm design. The BR design
process has to be implemented under the extreme
condition. But concerning that the emergency might occur
at the moment when the machine operates below the
maximum speed, three different discharge modes
including full-power, partial-power and bleeder-based
discharge modes are developed. The proposed discharge
techniques are verified by experiments which are
conducted on a three-phase SPMSM drive system used for
EVs. 7
Original languageEnglish
JournalIEEE Transactions on Industrial Electronics
Early online date26 Feb 2020
Publication statusE-pub ahead of print - 26 Feb 2020

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