A generator system includes a generator including terminals, a generator circuit breaker coupled to the terminals and that couples and decouples the generator from a power grid, multiple sensors, and a controller that operates the generator system. The controller determines whether an active power is less than a reverse active power threshold and whether one or more turbine valves are closed, and determines that a breaker failure has occurred based on the active power being less than the reverse active power threshold and the one or more turbine valves being closed. If the active power remains less than the reverse active power and the turbine valves remain closed after a threshold time period after the trip command, and if a reactive power is less than a reverse reactive power threshold, then a breaker failure has occurred. In response, the controller may transmit another trip command to the generator circuit breaker to initiate the breaker failure protection.

A motor driving system includes first and second motors including multiple first windings and second windings; a first inverter including a DC terminal connected to a DC voltage source and an AC terminal connected to the multiple first windings; a first switch part including a plurality of first mode change switches connected to the multiple first windings; a second inverter including a DC terminal connected to the DC voltage source and an AC terminal connected to the plurality of first mode change switches; a second switch part including a plurality of second mode change switches connected to the AC terminal of the second inverter and the multiple second windings; a third switch part including a plurality of third mode change switches connected to the multiple first windings; and a controller configured to control the short-circuited state or the open state of the multiple first mode, second and third mode change switches, based on whether the first and the second motors are driven.

A wireless power receiver includes a resonance circuit configured to generate an induced current based on a magnetic field generated by a wireless power transmitter, a diode connected to a first end of the resonance circuit and to a second end of the resonance circuit, and an inductive load connected to a first end of the diode and a second end of the diode.

Provided is a method of controlling a multi-channel multi-phase electrical machine including a plurality of channels each with a set of phase windings connected to a converter, which method includes the steps of operating the converters to electrically phase-shift the channels; computing harmonic injection currents for a dominant harmonic on the basis of electrical quantities in a rotating reference frame; determining harmonic voltage references for the dominant harmonic on the basis of the harmonic injection currents; and regulating the AC output voltages of the channels according to the fundamental voltage references and the harmonic voltage references. Also provided is a control arrangement of a multi-channel multi-phase electrical machine; a wind turbine; and a computer program product.

According to an aspect of the present invention, an electric working machine is provided. The electric working machine comprises a motor, an operation portion, a working portion, and a controller. The working portion is configured to be driven by the motor and act on a work target. The operation portion is configured to be operated by an operator. The controller is configured to control a maximum power that can be input to the motor to a first power when receiving an operation signal indicating an amount of operation to the operation portion. Further, the controller is configured to perform first switching control to switch the maximum power to a second power that is less than the first power when rotation speed of the motor becomes less than a first threshold due to a load on the working portion.

A motor controller comprises a switch circuit and a driving circuit. The switch circuit is coupled to a three-phase motor for driving the three-phase motor. The driving circuit generates a plurality of control signals to control the switch circuit. The motor controller utilizes a first pulse width modulation waveform and a second pulse width modulation waveform for driving the three-phase motor, where the first pulse width modulation waveform and the second pulse width modulation waveform have different frequencies from each other. The motor controller utilizes the second pulse width modulation waveform to detect a phase switching time point, where the frequency of the first pulse width modulation waveform is greater than the frequency of the second pulse width modulation waveform.

The present disclosure relates to a motor control device and method. The motor control device includes an inverter for driving a motor, a first shunt resistor connected to a first low-side switching element included in the inverter, a second shunt resistor connected to a second low-side switching element included in the inverter, a DC-link shunt resistor in series with the inverter, and a controller for controlling the inverter based on first current value measured through the first and second shunt resistors and a second current value measured through the DC-link shunt resistor.

Driver circuits are disclosed having a high-side switch and a low-side switch. A pre-charging circuit is provided to pre-charge the low-side switch. In other implementations, methods are disclosed which involve precharging a low-side switch.

A press device includes a press device main body and a main breaker to supply or stop power from an external power supply to the press device main body. The press device main body includes a slide, a bolster disposed below the slide, a servomotor configured to drive the slide, a power storage unit able to supply stored power to the servomotor, a discharge unit configured to discharge a charge stored in the power storage unit, and a first contactor. An upper die can be mounted on the slide. A lower die can be disposed on the bolster. The first contactor interrupts an electrical connection between the power storage unit and the discharge unit in an energized state and electrically connects the power storage unit and the discharge unit in a non-energized state. The first contactor is supplied with power for energization from the external power source without passing through the main breaker.

A control device for an AC rotary machine includes: a DC power supply; an inverter; a magnetic flux generator; an angle detector; and a control arithmetic unit; wherein the control arithmetic unit is configured to: calculate, based on a positional relationship between a current path and the angle detector, a correction signal for correcting signal errors of a cosine signal and a sine signal, which are caused by a noise magnetic flux component due to at least one of a DC current flowing between the DC power supply and the inverter and multi-phase AC currents flowing between the inverter and armature windings; and control the inverter by using angle information obtained from values after the correction by the correction signal.