Abstract: The converter device includes a rectification circuit that receives, as an input, AC power from an AC power supply, and performs full-wave rectification on the AC power received, a booster circuit that boosts an output voltage from the rectification circuit, a smoothing capacitor that smooths an output voltage from the booster circuit, and outputs a voltage smoothed, to the load, and a controller that controls the booster circuit. The booster circuit includes a plurality of booster sections each of which includes a reactor, a switching element, and a reverse-blocking diode. The controller maintains, in an ON state, the switching element included in at least one of the plurality of booster sections for a predetermined time period to determine the presence or absence of a fault of the booster section.

Abstract: A motor drive system can detect a misconnection. A motor drive system for driving a motor including a plurality of stator windings includes: an inverter that converts a DC voltage supplied from a DC voltage source into an AC voltage and applies the AC voltage to the motor; a connection switching device that is disposed between the inverter and the motor and can switch a connection state of the stator windings; and a controller that performs abnormality determination on a connection state of the connection switching device on the basis of a current value of a current flowing in each of the stator windings.

Abstract: A synchronous motor control device includes a voltage detector, a current detector, an inverter main circuit, and an inverter control unit. The inverter control unit includes: a phase current reproduction unit that reproduces a direct current into phase currents flowing to a permanent magnet synchronous motor; a current coordinate transformation unit that transforms the reproduced phase current into current on a control coordinate axis of a rotating coordinate system; a current control unit that calculates a voltage command value of the permanent magnet synchronous motor in such a manner that the current on the control coordinate axis equals a specific value; and a limiter unit that limits the value of the voltage command value.

Abstract: A converter device includes a rectifier circuit to rectify an AC voltage output from an AC power supply, a booster circuit including a plurality of reactors, a plurality of switching elements, and a plurality of backflow prevention elements to boost an output voltage of the rectifier circuit, a smoothing capacitor to smooth an output voltage of the booster circuit, a bus-current detection circuit to detect a value of a current that flows between the rectifier circuit and the booster circuit, a first filter circuit having a first filter time constant, a second filter circuit having a second filter time constant shorter than the first filter time constant, and a control unit to control an operation of the switching elements as a current value detected by the bus-current detection circuit is input to the control unit via the first filter circuit and the second filter circuit.

Abstract: The converter device includes a rectification circuit that receives, as an input, AC power from an AC power supply, and performs full-wave rectification on the AC power received, a booster circuit that boosts an output voltage from the rectification circuit, a smoothing capacitor that smooths an output voltage from the booster circuit, and outputs a voltage smoothed, to the load, and a controller that controls the booster circuit. The booster circuit includes a plurality of booster sections each of which includes a reactor, a switching element, and a reverse-blocking diode. The controller maintains, in an ON state, the switching element included in at least one of the plurality of booster sections for a predetermined time period to determine the presence or absence of a fault of the booster section.

Abstract: A synchronous motor control device includes: a DC power supply; an inverter main circuit; a three-phase synchronous motor; and an inverter control unit that outputs a PWM signal used to control the inverter main circuit. The inverter control unit includes: a PWM signal generation unit; a start-up control unit that outputs a start-up voltage command value to the PWM signal generation unit at the time of start-up; a steady state control unit that calculates a steady state voltage command value in a steady state and outputs the value to the PWM signal generation unit; and a steady state control parameter initial value calculation unit that outputs an initial value of a control parameter to the steady state control unit such that an output voltage vector from the inverter main circuit to the three-phase synchronous motor is consistent before and after switching from the start-up to the steady state.

Abstract: A synchronous motor control device includes a voltage detector, a current detector, an inverter main circuit, and an inverter control unit. The inverter control unit includes: a phase current reproduction unit that reproduces a direct current into phase currents flowing to a permanent magnet synchronous motor; a current coordinate transformation unit that transforms the reproduced phase current into current on a control coordinate axis of a rotating coordinate system; a current control unit that calculates a voltage command value of the permanent magnet synchronous motor in such a manner that the current on the control coordinate axis equals a specific value; and a limiter unit that limits the value of the voltage command value.