A motor driving apparatus includes a driving circuit that drives a motor based on a driving instruction signal at a first state of the first state and a second state which are binarized, a current feedback circuit including a latch circuit, and a controller that outputs the driving instruction signal and a current command signal. The latch circuit latches a third state of the third state and a fourth state which are binarized if a motor current value exceeds a current command value. When the driving instruction signal becomes the second state, the latch circuit releases the latching of the third state and outputs a signal of the fourth state. The controller outputs the driving instruction signal of the second state along with the current command signal so as to release the latching of the latch circuit when outputting the current command signal with the current command value changed.

According to embodiments, a drive circuit includes a control portion configured to, when a duty ratio is set to a first predetermined value, and a load apparatus is in an overload state, set the duty ratio to a second predetermined value smaller than the first predetermined value during a predetermined time period.

An electric propulsion machine includes an electric motor, an electric motor control circuit, a propulsion device to generate thrust from an output of the electric motor, and a battery unit to supply electric power to the electric motor. The battery unit includes a mode selector to accept a designation of an operating mode. The electric motor control circuit outputs a control signal that controls the electric motor based on an operating mode which is designated from among a plurality of operating modes.

A control device for an electric compressor, capable of successfully controlling a drive motor of the compressor in response to the load fluctuation having complicated frequency components even when the motor is controlled in a sensorless manner, is provided. The control device for an electric compressor includes: a repetitive control portion 5 to which a rotation speed difference between a target rotation speed of a motor which drives the compressor and the estimated rotation speed is input to perform a repetitive operation using the rotation speed difference of one preceding cycle of the compressor, thereby reducing the rotation speed difference; a pressure detecting portion 1 for the compressor; and a reset signal generation portion 4 calculating a timing of one rotation of the compressor by counting the number of predetermined parts of load fluctuations of the compressor based on the pressure value of the compressor, thereby outputting a reset signal to the repetitive control portion according to the timing.

A primary strut, which extends integrally from a heat sink main body, supports a circuit board at a location between a connector terminal and one of a switching device or a drive wiring. A secondary strut, which extends integrally from the heat sink main body, supports the circuit board at a location that is on an opposite side of the switching device and the drive wiring, which is opposite from the connector terminal. A temperature sensor is installed to the circuit board at a location, which is spaced from the primary strut, the switching device and the drive wiring, and at which the temperature sensor senses a temperature of the secondary strut. A control device limits an electric current supplied to the switching device upon estimating a temperature of the switching device while using the temperature, which is sensed with the temperature sensor, as a reference temperature.

Electromechanical systems using magnetic fields to induce eddy currents and generate lift are described. Magnet configurations which can be employed in the systems are illustrated. The magnet configuration can be used to generate lift and/or thrust. Arrangements of hover engines, which can employ the magnet configurations, are described. Methods of controlling translating hover engines to operate at a zero drag condition are described.

An electrical system includes a direct current (DC) voltage bus, a power supply providing a supply voltage to the DC voltage bus, an electric machine connected to the power supply, a reverse current protection (RCP) circuit positioned between the power supply and the electric machine, the RCP circuit including an energy dissipating element, and a controller. As part of an associated method, the controller detects a reverse current condition in which a current flows from the electric machine toward the power supply when an induced voltage of the electric machine exceeds a voltage level of the voltage bus. The controller transmits a control signal to the RCP circuit to direct the electrical current through the energy dissipating element for a duration of the reverse current condition or for a predetermined duration equal to or greater than that of the reverse current condition.

A system and method for determining the load in a material handling system is disclosed. The load weight detection system measures torque at four operating conditions both at constant speed and during acceleration. The level of torque generated by the motor under each of these operating conditions is stored in the motor drive. The motor drive also receives a signal corresponding to the speed of the hoist motor. Based on the measured torque, as well as the expected torque at no load and at rated load for the measured speed, the motor drive then determines the load present on the hoist. In some systems, two or more hoists are required to operate in tandem to lift a load. Each motor drive determines the weight of the load supported by its respective hoist motor and determines a total weight of the load based on the weights determined by each motor drive.

The invention relates to a device for controlling an alternator of the type that controls a DC voltage (B+A) generated by the alternator (11) according to a predetermined set voltage (U.sub.0) by monitoring the intensity of an energizing current (I.sub.EXC) flowing through an energizing circuit of the alternator. According to the invention, the device includes a voltage-control loop (7) and a temperature-control loop (17) which comprises a temperature sensor supplying a current temperature (T) of components of the alternator, a subtracter (19) supplying a temperature error (.sub.t) between the current temperature (T) and a maximum acceptable temperature (T.sub.max) and a control module (20) supplying a maximum admissible energizing percentage (r.sub.max) in accordance with the temperature error according to a predetermined control law.

An integrated controller for an operator unit for powering an overhead garage roller door or roller shutter is described. The operator unit comprises a motor, an output drive assembly, a timing assembly unit, and a clutch assembly for providing selective engagement between motor powered operation and manual operation (provided by a chain rotating a chain wheel). The motor is arranged to drive a shaft which, in turn, provides drive to the roller door or shutter assembly (not shown), which includes an axle around which the roller door or shutter is wound. The integrated controller comprises an inverter for receiving a single phase power supply and supplying three phase power to drive the motor; and a drive controller in operable association with the inverter for providing active management of the operation of the motor.