A method of protecting a converter of a wind turbine and a respective protection system are provided. The converter is coupled to a generator of the wind turbine to perform conversion of electrical power produced by the generator, the converter including plural semiconductor components that are operational to provide the conversion of the electrical power. The method includes the performing of a step of estimating a junction temperature of at least one of the semiconductor components by determining a current in the converter associated with power loss in one or more of the semiconductor components; estimating power loss associated with the one or more semiconductor components based on the determined current and on a state of the one or more semiconductor components; and using a thermal model to estimate the junction temperature of the semiconductor components based on the estimated power loss. The estimating step is repeatedly performed.

A processing machine includes: a static pressure bearing configured to support a drive shaft; a fluid feeder configured to output a fluid to be supplied to the static pressure bearing, in accordance with rotation of a servomotor; a sensor configured to detect a physical quantity of the fluid output from the fluid feeder; and a control unit configured to control the rotation speed of the servomotor according to the physical quantity of the fluid.

A processing machine includes: a static pressure bearing configured to support a drive shaft; a fluid feeder configured to output a fluid to be supplied to the static pressure bearing, in accordance with rotation of a servomotor; a sensor configured to detect a physical quantity of the fluid output from the fluid feeder; and a control unit configured to control the rotation speed of the servomotor according to the physical quantity of the fluid.

A cart may include: a driving wheel; a motor configured to rotate the driving wheel; a motor drive circuit configured to drive the motor; a motor brake circuit configured to electrically brake the motor; a rotation speed sensor configured to detect a rotation speed of the motor; and a control device configured to control the motor via the motor drive circuit and the motor brake circuit based on a target rotation speed of the motor and the rotation speed detected by the rotation speed sensor. The motor brake circuit may include an electronically variable resistance element configured to operate in a linear mode and a switching mode in response to a control input signal. The motor brake circuit may be configured to operate. the electronically variable resistance element in the linear mode when braking the motor.

A cart may include a driving wheel, a motor configured to rotate the driving wheel, a motor drive circuit configured to drive the motor, a motor brake circuit configured to electrically brake the motor, a control device configured to control the motor via the motor drive circuit and the motor brake circuit so that a travelling speed of the cart becomes equal to or lower than an upper limit travelling speed, and a temperature sensor configured to detect a temperature of the motor brake circuit. The control device may be configured to change the upper limit travelling speed to a second upper limit travelling speed lower than the first upper limit travelling speed when the upper limit travelling speed is a first upper limit travelling speed and the temperature detected by the temperature sensor exceeds a first predetermined temperature.

A fan control system according to the present disclosure includes a controller that selects a control mode from a plurality of control modes including a first mode and a second mode. The first mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at the first rotation speed. The second mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at a second rotation speed lower than the first rotation speed. The controller has a function of selecting the second mode in a period after the start of the fan motor and before the selection of the first mode.

A fan control system according to the present disclosure includes a controller that selects a control mode from a plurality of control modes including a first mode and a second mode. The first mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at the first rotation speed. The second mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at a second rotation speed lower than the first rotation speed. The controller has a function of selecting the second mode in a period after the start of the fan motor and before the selection of the first mode.

A motor driving device for driving a motor is provided. The motor driving device includes: a driver outputting a drive signal for driving the motor to the motor; and a controller controlling a duty ratio of the drive signal based on three control parameters which are an initial duty ratio, a duty ratio increasing speed, and a target duty ratio. The controller has a normal control mode in which each of the three control parameters is a predetermined value, and a cryogenic control mode in which at least one of the three control parameters is a smaller value than in the normal control mode.

A motor driving device for driving a motor is provided. The motor driving device includes: a driver outputting a drive signal for driving the motor to the motor; and a controller controlling a duty ratio of the drive signal based on three control parameters which are an initial duty ratio, a duty ratio increasing speed, and a target duty ratio. The controller has a normal control mode in which each of the three control parameters is a predetermined value, and a cryogenic control mode in which at least one of the three control parameters is a smaller value than in the normal control mode.

A steer-by-wire steering system including a steering device including a steering motor and a controller configured to supply a steering current to the steering motor based on a steering request. The controller includes a plurality of microcomputers, a plurality of drive circuits, and a plurality of temperature sensors. When a detection temperature difference that is a difference between detection temperatures of any two of the plurality of temperature sensors is greater than a predetermined threshold, each of the plurality of microcomputers executes an independent calculation control to independently calculate and set a current limit value, which is an upper limit value of the steering current, based on a detection temperature of one of the plurality of temperature sensors corresponding to itself, irrespective of detection temperatures of one or more of the plurality of temperature sensors other than the one of the plurality of temperature sensors corresponding to itself.