Patent ID: 8054020

Claim:
An electric motor for connection to a direct-current source ( 44 ), which motor ( 102 ) comprises: a DC link circuit ( 30 , 32 ); a permanent-magnet rotor ( 104 ; 232 ); a driver circuit having a full bridge ( 114 ; 200 ), in which semiconductor switches of one predetermined type are arranged in one bridge half that is connected to the one pole of the DC link circuit ( 30 , 32 ), and semiconductors of another predetermined type are arranged in the other bridge half that is connected to the other pole of the link circuit; a stator having a stator winding arrangement ( 106 ; 204 , 206 , 208 ), the current flow through said arrangement being controllable by the full bridge ( 114 ; 200 ); a program-controlled calculation arrangement ( 80 ) for controlling the full bridge ( 114 ; 200 ), which calculation arrangement ( 80 ) is configured to supply the semiconductor switches ( 120 , 124 ; 210 , 212 , 214 ) of a first bridge half with a PWM signal ( 136 , 136 ′, 136 ″, 136 ′″), and to supply the semiconductor switches ( 118 , 122 ; 218 , 220 , 222 ) of the other bridge half with a commutation signal (O 1 , O 2 ; 150 , 150 ′, 150 ″, 150 ′″) for the commutation of said semiconductor switches; a power supply device ( 52 ) for supplying power to the program-controlled calculation arrangement ( 80 ), which power supply device is separated by a diode arrangement ( 42 , 55 ) from the power supply system of the motor ( 102 ; 202 ) so that, in the event of a power outage, the program-controlled calculation arrangement ( 80 ) is deactivatable independently of the motor ( 102 ; 202 ) and then no longer supplies signals for the semiconductor switches of the full bridge; and at least one energy storage device ( 170 ) that is associated with at least one semiconductor switch ( 118 , 122 ; 218 , 220 , 222 ) of the other bridge half and, during operation of the motor ( 102 ; 202 ), is chargeable from the DC link circuit ( 30 , 32 ), a charge stored in the storage device serving, upon cessation of the signals from the program-controlled calculation arrangement ( 80 ), to make the at least one associated semiconductor switch ( 118 , 122 ; 218 , 220 , 222 ) of the other bridge half conductive, and thereby to short-circuit the stator winding arrangement ( 106 ; 204 , 206 , 208 ) through said at least one semiconductor switch ( 118 , 122 ; 218 , 220 , 222 ) so that the permanent-magnet rotor ( 104 ; 232 ) is automatically decelerated after cessation of the signals from the program-controlled calculation arrangement ( 80 ).