Abstract: An electric motor system includes a drive shaft, a first electric motor, a second electric motor, a first inverter, a second inverter and a control unit. The drive shaft is rotatable around an axis. The first electric motor and the second electric motor rotate the drive shaft. The first inverter supplies power in order to generate a torque to the first electric motor. The second inverter supplies power in order to generate a torque to the second electric motor. The control unit controls the first inverter and the second inverter. The controller is configured to be able to change a ratio between an output torque of the first electric motor and an output torque of the second electric motor.

Abstract: A fluid temperature control device includes a magnetic circuit portion and a coil waterproof structure. The magnetic circuit portion includes a magnetic working substance container containing a magnetic working substance, and a coil that applies a magnetic field to the magnetic working substance container. The magnetic working substance container allows a fluid to flow through it to exchange heat with the magnetic working substance. The coil waterproof structure hinders water generated in the magnetic working substance container from flowing to the coil.

Abstract: An inverter circuit (120) is configured so as to perform synchronous rectification by six switching elements (130). The switching element (130) is formed of an unipolar device (SiC MOSFET in this case) using a wideband gap semiconductor. The inverter circuit (120) uses the body diode (131) of SiC MOSFET (130) as a freewheeling diode during synchronous rectification.

Abstract: A detector detects whether or not a first line induced voltage and a second line induced voltage match each other, the first line induced voltage being a potential difference of a first phase potential of phase potentials relative to a reference potential, and the second line induced voltage being a potential difference of a second phase potential of the phase potentials other than the first phase potential relative to the reference potential. The phase potentials is outputted by the armature due to an induced electromotive force. The reference potential is any one of a minimum phase and a maximum phase. A rotation-position setting unit sets, to a predetermined value, an estimation value of a rotation position of the motor 2 at a point in time when the first line induced voltage and the second line induced voltage match each other.

Abstract: A subtractor subtracts an angular speed correction amount from a rotational speed command to obtain a corrected rotational speed command. An adder adds a second-axis current correction value to a ?c-axis current to obtain a corrected second-axis current. An angular ripple extraction unit obtains, from a rotational angle on a mechanical angle of a synchronous motor, a rotational angle difference being a ripple component of the rotational angle. An nth-order component extraction unit extracts nth-order components of a fundamental frequency of the rotational angle from the rotational angle difference. A torque conversion unit obtains nth-order components of an estimated value of vibration torque. A correction amount calculation unit obtains the second-axis current correction value using the nth-order components.

Abstract: A feedback amount calculation unit uses a deviation of a current from its command value or a deviation of an air-gap flux from its command value to calculate a feedback amount. A voltage error calculation unit calculates a variation range of a voltage error between a voltage value based on a voltage equation of the electric motor and a voltage command. The presence or absence of step-out of the electric motor is determined by comparison between the variation range of the voltage error and the feedback amount.

Abstract: An inverter circuit (120) is configured so as to perform synchronous rectification by six switching elements (130). The switching element (130) is formed of an unipolar device (SiC MOSFET in this case) using a wideband gap semiconductor. The inverter circuit (120) uses the body diode (131) of SiC MOSFET (130) as a freewheeling diode during synchronous rectification.

Abstract: A subtractor subtracts an angular speed correction amount from a rotational speed command to obtain a corrected rotational speed command. An adder adds a second-axis current correction value to a ?c-axis current to obtain a corrected second-axis current. An angular ripple extraction unit obtains, from a rotational angle on a mechanical angle of a synchronous motor, a rotational angle difference being a ripple component of the rotational angle. An nth-order component extraction unit extracts nth-order components of a fundamental frequency of the rotational angle from the rotational angle difference. A torque conversion unit obtains nth-order components of an estimated value of vibration torque. A correction amount calculation unit obtains the second-axis current correction value using the nth-order components.

Abstract: An inverter circuit (120) is configured so as to perform synchronous rectification by six switching elements (130). The switching element (130) is formed of an unipolar device (SiC MOSFET in this case) using a wideband gap semiconductor. The inverter circuit (120) uses the body diode (131) of SiC MOSFET (130) as a freewheeling diode during synchronous rectification.

Abstract: A feedback amount calculation unit uses a deviation of a current from its command value or a deviation of an air-gap flux from its command value to calculate a feedback amount. A voltage error calculation unit calculates a variation range of a voltage error between a voltage value based on a voltage equation of the electric motor and a voltage command. The presence or absence of step-out of the electric motor is determined by comparison between the variation range of the voltage error and the feedback amount.

Abstract: A DC link is provided, which includes a capacitor connected in parallel to an output of a converter circuit, and outputs a pulsating DC link voltage. An inverter circuit is provided, which converts an output of the DC link to AC by switching, and supplies the AC to a motor connected thereto. A controller is provided, which controls switching of the inverter circuit so that motor currents pulsate in synchronization with pulsation of a power-supply voltage. The controller controls the switching of the inverter circuit in accordance with a load of the motor or an operational state of the motor, and reduces pulsation amplitude of the motor currents.

Abstract: A bidirectional switch circuit includes two switching elements connected to conduct a current in both directions. The two switching elements are connected in series to each other. Of the two switching elements, the switching element to which a reverse voltage is applied, a voltage of a source of one of the switching elements being higher than a voltage of a drain of the one, is configured to conduct a current from the source to the drain even when an on-drive signal is not being input to a gate terminal of the one.

Abstract: A detector detects whether or not a first line induced voltage and a second line induced voltage match each other, the first line induced voltage being a potential difference of a first phase potential of phase potentials relative to a reference potential, and the second line induced voltage being a potential difference of a second phase potential of the phase potentials other than the first phase potential relative to the reference potential. The phase potentials is outputted by the armature due to an induced electromotive force. The reference potential is any one of a minimum phase and a maximum phase. A rotation-position setting unit sets, to a predetermined value, an estimation value of a rotation position of the motor 2 at a point in time when the first line induced voltage and the second line induced voltage match each other.

Abstract: A carrier generating unit applies a carrier that monotonically decreases to a switching control unit during either one of a first period that is a period immediately following a period in which a voltage command value is a value not more than a minimum value of the carrier, the voltage command value taking a first predetermined value larger than the minimum value of the carrier in the first period, and a second period that is a period immediately preceding a period in which the voltage command value is not less than a maximum value of the carrier, the voltage command value taking a second predetermined value smaller than the maximum value in the second period.

Abstract: A DC voltage value from a DC voltage detection section is input directly to a voltage correction section without passing through a compensator or a filter. Therefore, even when rapid voltage change occurs, such as short power interruptions, instantaneous voltage drop and return from instantaneous voltage drop, the voltage correction section can quickly perform the correction operation in response to the rapid voltage change. Since the amount of link resonance compensation is limited by the limitation section to a certain range, it is possible to prevent the amount of link resonance compensation from fluctuating excessively upon rapid voltage change. Since the amount of link resonance compensation which is limited by the limitation section to a certain range is input to one compensator that has an appropriate control band, among all control calculation sections, the response does not have to be unnecessarily fast, thus realizing a stable control.

Abstract: A control section which repeats inverter control in units of an inverter control period having a predetermined length is provided. In the control section, a phase current detection period in which a phase current is detected is provided between predetermined two inverter control periods, each of switching states of switching elements of a inverter circuit is controlled so that a voltage pulse having a larger width than a width of a voltage pulse in the inverter control period is output from a shunt resistor in the phase current detection period.

Abstract: A carrier generating unit applies a carrier that monotonically decreases to a switching control unit during either one of a first period that is a period immediately following a period in which a voltage command value is a value not more than a minimum value of the carrier, the voltage command value taking a first predetermined value larger than the minimum value of the carrier in the first period, and a second period that is a period immediately preceding a period in which the voltage command value is not less than a maximum value of the carrier, the voltage command value taking a second predetermined value smaller than the maximum value in the second period.

Abstract: The power converter includes a diode rectifier which rectifies alternating current power output from an alternating current power supply, a reactor provided between the alternating current power supply and the diode rectifier, an inverter circuit to which power output from the diode rectifier is directly supplied, and a capacitor provided between power supply lines on a primary side of the diode rectifier.

Abstract: A control section which repeats inverter control in units of an inverter control period having a predetermined length is provided. In the control section, a phase current detection period in which a phase current is detected is provided between predetermined two inverter control periods, each of switching states of switching elements of a inverter circuit is controlled so that a voltage pulse having a larger width than a width of a voltage pulse in the inverter control period is output from a shunt resistor in the phase current detection period.

Abstract: A DC voltage value from a DC voltage detection section is input directly to a voltage correction section without passing through a compensator or a filter. Therefore, even when rapid voltage change occurs, such as short power interruptions, instantaneous voltage drop and return from instantaneous voltage drop, the voltage correction section can quickly perform the correction operation in response to the rapid voltage change. Since the amount of link resonance compensation is limited by the limitation section to a certain range, it is possible to prevent the amount of link resonance compensation from fluctuating excessively upon rapid voltage change. Since the amount of link resonance compensation which is limited by the limitation section to a certain range is input to one compensator that has an appropriate control band, among all control calculation sections, the response does not have to be unnecessarily fast, thus realizing a stable control.