Abstract: A power converting apparatus includes: a boost circuit including a reactor supplied with first voltage output from an alternating-current power supply, a first leg including first upper-arm and lower-arm switching elements connected in series, and a second leg connected in parallel with the first leg and including second upper-arm and lower-arm switching elements connected in series, and boosting the first voltage; a first voltage detecting unit detecting the first voltage; a smoothing capacitor smoothing voltage output from the boost circuit; and a second voltage detecting unit detecting second voltage smoothed by the smoothing capacitor. When the second voltage is larger than the first voltage and is lower than or equal to twice the first voltage, a width of a second drive pulse to turn on the first upper-arm switching element is larger than a width of a first drive pulse to turn on the first lower-arm switching element.

Abstract: In a motor driving apparatus including a DC power supply circuit of variable output voltage value, an inverter of variable frequency, and a connection switching device for selecting connection, switching of the connection switching device is performed in a state where an output voltage of the DC power supply circuit is increased, a rotational speed of a motor is increased, and a current flowing through the motor is made not greater than a predetermined threshold. For example, the switching of the connection switching device is performed in a state where the current through the motor is made zero. For example, the switching is performed in a state where the output voltage of the DC power supply circuit is set at a value corresponding to the rotational speed of the motor during the switching. It is possible to prevent increase in apparatus size and switch the connection of windings while the motor is rotating.

Abstract: There are provided an inverter connected to n (n being as integer not less than 2) motors each including a rotor having a permanent magnet and capable of driving the n motors, and a connection switching device to switch a connection state of at least one motor of the n motors and the inverter between connection and disconnection. While the n motors are connected to the inverter and driven by the inverter, when an abnormality is detected in the at least one motor, the connection switching device switches the connection state to the disconnection and the inverter drives the n motors except the at least one motor.

Abstract: In a motor driving apparatus having an inverter for driving a motor capable of switching between a star connection and a delta connection, when currents detected by winding current detecting elements detecting currents flowing through windings become excessive, the inverter is made to stop. Moreover, inverter output currents are calculated after removing a circulating current component at the time of the delta connection, from the winding currents detected by the winding current detecting elements, and the inverter is controlled using the calculated inverter output currents. Because over-current protection is performed based on the detected values of the winding currents, it is possible to prevent demagnetization taking account oSf the circulating current. Also, the inverter control is prevented from being affected by the circulating current in the delta connection. Accordingly, it is possible to reduce the number of the current detecting elements, and perform the over-current protection and control properly.

Abstract: An over-current protection circuit for a motor capable of selecting one of a plurality of connection states has a plurality of decision circuits, a combining circuit, and a nullifying circuit. The combining circuit combines results of the comparisons in the plurality of decision circuits. The nullifying circuit nullifies part of the comparisons in the plurality of decision circuits. The number of outputs of the over-current protection circuit is one, so that for controlling the driving and stopping of the inverter needs just one terminal is required for receiving the output of the combining circuit. Moreover, because the over-current protection circuit is formed of hardware, the protection can be performed at a high speed.

Abstract: An over-current protection circuit for a motor capable of selecting one of a plurality of connection states has a plurality of decision circuits, a combining circuit, and a nullifying circuit. The combining circuit combines results of the comparisons in the plurality of decision circuits. The nullifying circuit nullifies part of the comparisons in the plurality of decision circuits. The number of outputs of the over-current protection circuit is one, so that for controlling the driving and stopping of the inverter needs just one terminal is required for receiving the output of the combining circuit. Moreover, because the over-current protection circuit is formed of hardware, the protection can be performed at a high speed.

Abstract: An electric-motor driving apparatus according to the present invention is the electric-motor driving apparatus that drives an electric motor having a winding structure in which a first multi-phase winding and a second multi-phase winding are wound and includes a first DC/AC converter connected to the first multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a second DC/AC converter connected to the second multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a first three-phase switching unit to perform connecting and disconnecting between phases of the first multi-phase winding, a second three-phase switching unit to perform connecting and disconnecting between phases of the second multi-phase winding, and a winding switching unit to perform connecting and disconnecting between the first multi-phase winding and the second multi-phase winding.

Abstract: A motor system according to the present invention includes: a motor including a first winding portion and a second winding portion, the second winding portion having a larger number of turns than the first winding portion; a first inverter connected to the first winding portion; and a second inverter connected to the second winding portion.

Abstract: A power converting apparatus includes: a boost circuit including a reactor supplied with first voltage output from an alternating-current power supply, a first leg including first upper-arm and lower-arm switching elements connected in series, and a second leg connected in parallel with the first leg and including second upper-arm and lower-arm switching elements connected in series, and boosting the first voltage; a first voltage detecting unit detecting the first voltage; a smoothing capacitor smoothing voltage output from the boost circuit; and a second voltage detecting unit detecting second voltage smoothed by the smoothing capacitor. When the second voltage is larger than the first voltage and is lower than or equal to twice the first voltage, a width of a second drive pulse to turn on the first upper-arm switching element is larger than a width of a first drive pulse to turn on the first lower-arm switching element.

Abstract: An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate a DC voltage, an inverter to generate three-phase AC voltages from the DC voltage, a motor to produce a driving force for driving the compressor with a plurality of coils, the three-phase AC voltages being applied to the coils, a connection switching unit to switch connection states of the coils between a first connection state and a second connection state, and a controller to detect an abnormality of the connection switching unit.

Abstract: An over-current protection circuit for a motor capable of selecting one of a plurality of connection states has a plurality of decision circuits, a combining circuit, and a nullifying circuit. The combining circuit combines results of the comparisons in the plurality of decision circuits. The nullifying circuit nullifies part of the comparisons in the plurality of decision circuits. The number of outputs of the over-current protection circuit is one, so that for controlling the driving and stopping of the inverter needs just one terminal is required for receiving the output of the combining circuit. Moreover, because the over-current protection circuit is formed of hardware, the protection can be performed at a high speed.

Abstract: An electric-motor driving apparatus is used to drive an electric motor including a plurality of winding groups constituting a three-phase winding. The electric-motor driving apparatus includes a switch that switches connection of windings of a first winding group and a second winding group, an inverter that drives an electric motor, and a controller that controls the inverter and the switch.

Abstract: In a motor driving apparatus having an inverter for driving a motor capable of switching between a star connection and a delta connection, when currents detected by winding current detecting elements detecting currents flowing through windings become excessive, the inverter is made to stop. Moreover, inverter output currents are calculated after removing a circulating current component at the time of the delta connection, from the winding currents detected by the winding current detecting elements, and the inverter is controlled using the calculated inverter output currents. Because over-current protection is performed based on the detected values of the winding currents, it is possible to prevent demagnetization taking account oSf the circulating current. Also, the inverter control is prevented from being affected by the circulating current in the delta connection. Accordingly, it is possible to reduce the number of the current detecting elements, and perform the over-current protection and control properly.

Abstract: An electric-motor driving apparatus according to the present invention is the electric-motor driving apparatus that drives an electric motor having a winding structure in which a first multi-phase winding and a second multi-phase winding are wound and includes a first DC/AC converter connected to the first multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a second DC/AC converter connected to the second multi-phase winding and applying a multi-phase alternating-current voltage to the electric motor, a first three-phase switching unit to perform connecting and disconnecting between phases of the first multi-phase winding, a second three-phase switching unit to perform connecting and disconnecting between phases of the second multi-phase winding, and a winding switching unit to perform connecting and disconnecting between the first multi-phase winding and the second multi-phase winding.

Abstract: A motor system according to the present invention includes: a motor including a first winding portion and a second winding portion, the second winding portion having a larger number of turns than the first winding portion; a first inverter connected to the first winding portion; and a second inverter connected to the second winding portion.