Abstract: Provided is a air purge device that can effectively discharge air.

Abstract: A setting unit sets a duty ratio of a PWM signal based on a target voltage value, and outputs the duty ratio to a voltage conversion circuit. An estimated value calculation unit cyclically calculates an estimated duty ratio value based on the detected input voltage value and the detected output voltage value. An abnormality detection unit cyclically calculates, as a difference value, a difference between an updated estimated value and a comparison reference value, and detects abnormality of a voltage detection unit based on a change in calculated difference value. The updated estimated value is a newly calculated estimated duty ratio value. The comparison reference value is a value based on the estimated duty ratio value calculated in a cycle prior to a cycle in which the updated estimated value is calculated.

Abstract: An inverter is provided for driving a motor. A first capacitor, and a second capacitor including capacitors connected in series, are connected in parallel to a DC power supply. A switch circuit having switching elements is connected between the inverter and the second capacitor. A control circuit is provided for controlling the inverter and the switch circuit. The control circuit performs control to switch the switch circuit so as to supply current from the second capacitor to the inverter during 3-level operation, and supply current from both of the first capacitor and the second capacitor to the inverter during 2-level operation.

Abstract: A power conversion device and a motor system according to the present disclosure comprises an inverter circuit which is connected to a motor, a switch circuit, and a control circuit. The power conversion device and the motor system are characterized in that the inverter circuit and the switch circuit are capable of two-level operation and three-level operation, and the control circuit switches between the two-level operation and the three-level operation on the basis of the motor torque command and the rotational speed command. As a result, it is possible to reduce the total loss in the power conversion device and the motor.

Abstract: An inverter is provided for driving a motor. A first capacitor, and a second capacitor including capacitors connected in series, are connected in parallel to a DC power supply. A switch circuit having switching elements is connected between the inverter and the second capacitor. A control circuit is provided for controlling the inverter and the switch circuit. The control circuit performs control to switch the switch circuit so as to supply current from the second capacitor to the inverter during 3-level operation, and supply current from both of the first capacitor and the second capacitor to the inverter during 2-level operation.

Abstract: A specific heat based moisture sensor comprises: a cylindrical member formed with two parallel axially-extending hollow portions; a heater provided on an outer circumferential surface of the cylindrical member; a temperature sensor formed by leads passed through the two hollow portions of the cylindrical member; and a waterproof synthetic resin formed so as to cover said cylindrical member and the heater. Since the difference in distance between the heater and the temperature sensor lead is determined precisely, the sensing reliability can be improved. Since the ceramic cylindrical member is used, temperature sensitivity can be improved. Since the sensor is covered with a waterproof resin, it is possible to prevent metallic ions from entering the substance to be sensed, without increasing the size and cost of the moisture sensor.