| 摘要 |
<p>Variable speed rotary electrical machines, specifically induction motors and motor drive systems. A main induction motor (15) and an auxiliary induction motor (17) have respective stators (21) housed in a common housing (19) and have respective rotors (23, 27) which are electrically concatenated and mounted on a common shaft (29). The main stator (21) is supplied with a constant a.c. voltage by a main inverter (35) connected to a constant-voltage d.c. link (45, 47, 43) and the auxiliary stator is supplied with a variable a.c. voltage by an auxiliary inventor (37) which is forced-commutated and connected to a variable-voltage d.c. link.
<??>A controller (40) controls the gating of the inverters (35, 37) and enables the forced-commutated inverter (37) to supply an a.c. signal of selected frequency and voltage level to the auxiliary stator such that a prescribed reactive power will be coupled through the auxiliary and main rotors (27, 23) to the main stator (21) to cause the latter to appear to constitute a leading power factor load, permitting the main inverter (35) to be line-commutated and supplied from a substantially constant voltage d.c. link. Alternatively, a drive system may comprise a plurality of the machines each with a main motor and an auxiliary motor. The stators of the main machines are all supplied from a single common main inverter which is line-commutated and the stators of the auxiliary machines are separately supplied from separate forced-commutated auxiliary inverters. </p> |
