Abstract: A pulse width modulation (PWM) interleaving system is provided. The PWM interleaving system includes active harmonic filters (AHFs). The AHFs are disposed in parallel with each other and with a load. The AHFs are electrically coupled to a common coupling point that is electrically interposed between a grid and the load. The AHFs are configured to affect, by PWM, a characteristic of current flowing between the grid and the load. The PWM interleaving system further includes a controller operably coupled to the AHFs and configured to synchronize the PWMs of the AHFs to thereby cancel ripple currents propagating towards the grid.

Abstract: A pulse width modulation (PWM) interleaving system is provided. The PWM interleaving system includes active harmonic filters (AHFs). The AHFs are disposed in parallel with each other and with a load. The AHFs are electrically coupled to a common coupling point that is electrically interposed between a grid and the load. The AHFs are configured to affect, by PWM, a characteristic of current flowing between the grid and the load. The PWM interleaving system further includes a controller operably coupled to the AHFs and configured to synchronize the PWMs of the AHFs to thereby cancel ripple currents propagating towards the grid.

Abstract: A conveyance system includes a machine having a motor; a source of AC power; a drive system coupled to the source of AC power, the drive system to provide multi-phase drive signals to the motor, the drive system including: a first drive having a first converter and a first inverter, the first convertor including a first positive DC bus and a first negative DC bus; a second drive having a second converter and a second inverter, the second convertor including a second positive DC bus and a second negative DC bus; wherein the first positive DC bus and the second DC positive bus are electrically connected and the first negative DC bus and the second negative DC bus are electrically connected.

Abstract: A conveyance system includes a machine having a motor; a source of AC power; a drive system coupled to the source of AC power, the drive system to provide multi-phase drive signals to the motor, the drive system including: a first drive having a first converter and a first inverter, the first convertor including a first positive DC bus and a first negative DC bus; a second drive having a second converter and a second inverter, the second convertor including a second positive DC bus and a second negative DC bus; wherein the first positive DC bus and the second DC positive bus are electrically connected and the first negative DC bus and the second negative DC bus are electrically connected.

Abstract: A hoist motor (12) for an elevator (14) is continuously driven from an irregular power supply (16). A regenerative drive (10) delivers power between the power supply (16) and the hoist motor (12). A controller (11) measures a power supply voltage in response to a detected change in the power supply voltage and controls the regenerative drive (10) to adjust a nominal motion profile of the elevator (14) in proportion with an adjustment ratio of the measured power supply voltage to a normal power supply voltage.

Abstract: An encoder failure in an elevator drive system is detected and managed. A velocity of the elevator drive system is provided by an encoder signal (60) and compared with a minimum velocity threshold (62). An encoder fault timer is incremented when the velocity is less than the minimum velocity threshold (64). The elevator drive system is disabled when the encoder fault timer reaches a fault threshold time (66).

Abstract: A hoist motor (12) for an elevator (14) is continuously driven from an irregular power supply (16). A regenerative drive (10) delivers power between the power supply (16) and the hoist motor (12). A controller (11) measures a power supply voltage in response to a detected change in the power supply voltage and controls the regenerative drive (10) to adjust a nominal motion profile of the elevator (14) in proportion with an adjustment ratio of the measured power supply voltage to a normal power supply voltage.

Abstract: An encoder failure in an elevator drive system is detected and managed. A velocity of the elevator drive system is provided by an encoder signal (60) and compared with a minimum velocity threshold (62). An encoder fault timer is incremented when the velocity is less than the minimum velocity threshold (64). The elevator drive system is disabled when the encoder fault timer reaches a fault threshold time (66).

Abstract: Elevator system hall fixtures such as lanterns, hall call button switches and lights, gongs, and floor position indicators are connected to a controller via wireless transceivers. The controller can be a system, group, and/or car controller. A low power wireless system connects all fixtures on one hallway, with a higher power wireless system connecting each hallway with the appropriate controller.

Abstract: Elevator system hall fixtures such as lanterns, hall call button switches and lights, gongs, and floor position indicators are connected to a controller via wireless transceivers. The controller can be a system, group, and/or car controller. A low power wireless system connects all fixtures on one hallway, with a higher power wireless system connecting each hallway with the appropriate controller.

Abstract: In a pulse width modulation-controlled, switched bridge, DC converter, the phase angle (44, 45) of the AC mains (4) is provided without sensing the voltage thereof, by a phase-locked loop (47) having one input (75) derived (126) from the in-phase voltage command Vde* (61) and another finit (77) approximating the line frequency; the phase-locked loop is initialized at a phase angle &thgr;init(76) equal to the arctangent (124) of the in-phase Vdest, and quadrature Vqest representation of estimated line voltages ere, ese, ete (119-121) derived during an initialization cycle from reconstruction of the fundamental component of the AC main currents at a phase angle (93) changing with said frequency. Reconstruction includes providing the discrete Fourier transform (DFT, 81) of signals indicative of currents (37) in the AC mains and the inverse DFT (122) of the resultant Fourier coefficients eia, eib.

Abstract: A system for position loss recovery for an elevator car includes a plurality of pairs of encoded floor magnets that uniquely identify each floor. Upon restoration of power, the encoded floor magnets are sensed by an encoded floor sensor and the precise floor location of the elevator car is determined.