Abstract: Motor control architecture including a travel, a hoist, and a controller is disclosed. The travel disposed on a main rail having an auxiliary-encoder includes a master-driver and a slave-driver for driving two motors. Each motor has a main-encoder. The hoist drives a rope and calculates a rope length continuously. The controller calculates an anti-sway position command based on the rope-length and a position command. The two drivers perform a full closed-loop computation based on a feedback of one main-encoder, a feedback of the auxiliary-encoder, and the anti-sway position command. Wherein, the master-driver controls one motor based on a speed command generated by the full closed-loop computation and the slave-driver follows the speed command and a torque command of the master-driver to drive another motor; or the two drivers compensate the torque command based on an error value between the feedback of one main-encoder and the feedback of the auxiliary-encoder.

Abstract: Motor control architecture including a travel, a hoist, and a controller is disclosed. The travel disposed on a main rail having an auxiliary-encoder includes a master-driver and a slave-driver for driving two motors. Each motor has a main-encoder. The hoist drives a rope and calculates a rope length continuously. The controller calculates an anti-sway position command based on the rope-length and a position command. The two drivers perform a full closed-loop computation based on a feedback of one main-encoder, a feedback of the auxiliary-encoder, and the anti-sway position command. Wherein, the master-driver controls one motor based on a speed command generated by the full closed-loop computation and the slave-driver follows the speed command and a torque command of the master-driver to drive another motor; or the two drivers compensate the torque command based on an error value between the feedback of one main-encoder and the feedback of the auxiliary-encoder.

Abstract: A method of detecting phase loss of a three-phase AC power source includes steps of: acquiring any two line voltages of the AC power source with a first cycle period, acquiring a first digital signal and a second digital signal, performing an exclusive OR operation between the first digital signal and the second digital signal to generate a level signal, accumulating a high-level time count value, or accumulating a low-level time count value, resetting the low-level time count value when the high-level time count value is accumulated, or resetting the high-level time count value when the low-level time count value is accumulated, and determining that the AC power source occurs a phase-loss abnormality when the high-level time count value is greater than or equal to ? of the first cycle period or the low-level time count value is greater than or equal to ? of the first cycle period.

Abstract: A method of detecting phase loss of a three-phase AC power source includes steps of: acquiring any two line voltages of the AC power source with a first cycle period, acquiring a first digital signal and a second digital signal, performing an exclusive OR operation between the first digital signal and the second digital signal to generate a level signal, accumulating a high-level time count value, or accumulating a low-level time count value, resetting the low-level time count value when the high-level time count value is accumulated, or resetting the high-level time count value when the low-level time count value is accumulated, and determining that the AC power source occurs a phase-loss abnormality when the high-level time count value is greater than or equal to ? of the first cycle period or the low-level time count value is greater than or equal to ? of the first cycle period.

Abstract: A control method is used with a control system to control a screw pump. The control system includes an electric motor and a motor drive. The control method includes following steps. Firstly, a DC bus voltage is monitored. If the DC bus voltage is smaller than a first threshold value, a potential energy stored in the pump screw and released by a backspin action is converted into a regenerative electrical energy so as to maintain a normal operation of the motor drive. Then, the motor drive drives the electric motor to control the backspin action of the screw pump according to a backspin torque limit strategy. If the electrical power from the power source is not restored and the level of a reverse regenerative torque is smaller than a preset torque value, the backspin action of the screw pump is stopped freely.

Abstract: A control method is used with a control system to control a screw pump. The control system includes an electric motor and a motor drive. The control method includes following steps. Firstly, a DC bus voltage is monitored. If the DC bus voltage is smaller than a first threshold value, a potential energy stored in the pump screw and released by a backspin action is converted into a regenerative electrical energy so as to maintain a normal operation of the motor drive. Then, the motor drive drives the electric motor to control the backspin action of the screw pump according to a backspin torque limit strategy. If the electrical power from the power source is not restored and the level of a reverse regenerative torque is smaller than a preset torque value, the backspin action of the screw pump is stopped freely.

Abstract: Proposed is a parallel inverter drive system including includes a plurality of inverter drives connected in parallel with each other, in which each inverter drive includes a switch; a PWM controller connected to the switch for controlling switching operations of the switch device according to a duty cycle signal; and a circulating current suppressor for collecting current information associated with the current of each inverter drive and a summation current, and generating an index according to the collected current information and the desired circulating current quantity. A zero-sequence voltage is generated for each phase of a three-phase voltage command according to the index and the voltage command and the operating mode of the inverter drive, thereby injecting the zero-sequence voltage into the voltage command with a feed-forward configuration so as to fix the voltage command. The PWM controller can generate the duty cycle signal according to the fixed voltage command.

Abstract: Proposed is a parallel inverter drive system including includes a plurality of inverter drives connected in parallel with each other, in which each inverter drive includes a switch; a PWM controller connected to the switch for controlling switching operations of the switch device according to a duty cycle signal; and a circulating current suppressor for collecting current information associated with the current of each inverter drive and a summation current, and generating an index according to the collected current information and the desired circulating current quantity. A zero-sequence voltage is generated for each phase of a three-phase voltage command according to the index and the voltage command and the operating mode of the inverter drive, thereby injecting the zero-sequence voltage into the voltage command with a feed-forward configuration so as to fix the voltage command. The PWM controller can generate the duty cycle signal according to the fixed voltage command.