Abstract: A three-phase multilevel inverter is connected to a first direct-current voltage source having a first voltage. Single-phase inverters are each connected in series to a corresponding phase of the three-phase multilevel inverter, and include a second direct-current voltage source, respectively, each having a second voltage. Combined output voltages, which are combinations of boost voltages generated by the three single-phase inverters and output voltages of the three-phase multilevel inverter, are supplied to a load. The control device adjusts a common mode voltage of the combined output voltages to be within a predetermined allowable range, and variation ranges of the line voltages in the combined output voltages to satisfy a specified condition established with the second voltage as a reference.

Abstract: A motor control device includes: a power source device including a DC-output power conversion device having a first mode for outputting first voltage and a second mode for outputting second voltage higher than the first voltage; a power supply device; and a control device, and controls a motor. When a flying object takes off, the control device controls the power conversion device in the second mode. When the control device judges that flight information which is one or both of information of a motor parameter obtained along with control for the motor and information of an environmental factor relevant to the flight altitude satisfies a predetermined condition, or when the control device has received an operation mode signal for which the first mode is selected on the basis of the flight information during control for the motor, the control device controls the power conversion device in the first mode.

Abstract: A motor control device includes: a step-down device including a DC-output power conversion device having a first mode for outputting first voltage and a second mode for outputting second voltage lower than the first voltage; a power supply device; and a control device, and controls a motor. When a flying object takes off, the control device controls the power conversion device in the first mode. When the control device judges that flight information which is one or both of information of a motor parameter obtained along with control for the motor and information of an environmental factor relevant to the flight altitude of satisfies a predetermined condition, or when the control device has received an mode signal for which the second mode is selected on the basis of the flight information during control for the motor, the control device controls the power conversion device in the second mode.

Abstract: A three-phase multilevel inverter is connected to a first direct-current voltage source having a first voltage. Single-phase inverters are each connected in series to a corresponding phase of the three-phase multilevel inverter, and include a second direct-current voltage source, respectively, each having a second voltage. Combined output voltages, which are combinations of boost voltages generated by the three single-phase inverters and output voltages of the three-phase multilevel inverter, are supplied to a load. The control device adjusts a common mode voltage of the combined output voltages to be within a predetermined allowable range, and variation ranges of the line voltages in the combined output voltages to satisfy a specified condition established with the second voltage as a reference.

Abstract: A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.

Abstract: A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.