Motor drive system

A motor drive system comprising:

• a rechargeable power storage device;
• a power control unit configured to drive a motor by using electric power supplied from said power storage device;
• an open/close device disposed on a power line connecting said power storage device to said power control unit;
• a first interlock mechanism configured to be activated to open said open/close device in response to transition to an operable state of an interruption device for interrupting an output of said power storage device;
• a second interlock mechanism configured to be activated to open said open/close device in response to transition to an openable state of a case containing said power control unit;
• and
• a control device for controlling said power control unit and said first and second interlock mechanisms,
• said power control unit including
• an inverter for converting the electric power from said power storage device to electric power for driving said motor, and
• a capacitor connected to a terminal of said inverter on the side of said power storage device,
• said control device being configured to perform, when said first interlock mechanism is activated, a first process of opening said open/close device after shutting down said power control unit, and to perform, when said second interlock mechanism is activated, a second process of opening said open/close device while driving said power control unit, instead of said first process, depending on a counter electromotive voltage generated by said motor.