Abstract: A motor-driven compressor includes an electric motor driven by a motor driver, which includes a switching element that converts DC voltage from a battery to AC voltage. A control unit controls the switching operation of the switching element. A temperature detector detects the temperature of the switching element. The control unit suspends the switching operation of the switching element when the temperature detected by the temperature detector rises to a temperature threshold. The temperature threshold includes a first temperature threshold, corresponding to a withstand temperature of the switching element, and a second temperature threshold, which is higher than the first temperature threshold. The control unit switches the temperature threshold from the first temperature threshold to the second temperature threshold when the control unit activates a field weakening control that reduces counter electromotive force generated by the electric motor.

Abstract: An in-vehicle motor-driven compressor includes a housing, a compression portion, an electric motor, and an inverter device. The inverter device includes a low-pass filter circuit, which reduces normal-mode noise included in DC power, and an inverter circuit, which converts the DC power into AC power. The low-pass filter circuit includes a normal-mode coil, which includes a pillar-shaped core extending in one direction and a winding wound around the core and forms an open magnetic circuit. The core includes two end faces in a direction in which the core extends. The inverter device includes a damping portion. The damping portion is arranged at a position where the damping portion is opposed to at least one of the two end faces of the core and an eddy current is generated by magnetic force lines produced in the normal-mode coil.

Abstract: An in-vehicle inverter driving device is used to perform PWM control of an inverter circuit that drives an electric motor. The electric motor includes a rotor having a permanent magnet and a stator about which three-phase coils are wound. The in-vehicle inverter driving device includes a bootstrap circuit, which uses a capacitor to turn ON upper arm switching elements of the inverter circuit. The in-vehicle inverter driving circuit includes a PWM control section that controls the inverter circuit by a lower-arm-fixing two-phase modulation method. The PWM control section performs shift correction and dead-time correction in the lower-arm-fixing two-phase modulation method.

Abstract: A motor-driven compressor includes an electric motor driven by a motor driver, which includes a switching element that converts DC voltage from a battery to AC voltage. A control unit controls the switching operation of the switching element. A temperature detector detects the temperature of the switching element. A voltage detector detects DC voltage applied to the switching element from the battery. The control unit suspends the switching operation of the switching element when the temperature detected by the temperature detector rises to a predetermined temperature threshold. The control unit also reduces counter electromotive force generated by the electric motor. The temperature threshold includes a first temperature threshold, corresponding to a withstand temperature of the switching element, and a second temperature threshold, which is higher than the first temperature threshold. The control unit switches the temperature threshold between the first and second temperature thresholds.

Abstract: A protective device protects an LC filter in a vehicle. The vehicle includes a first vehicle-mounted electric device and a second vehicle-mounted electric device. The first vehicle-mounted electric device includes a first power converter. The second vehicle-mounted electric device includes a second power converter and shares a power supply with the first vehicle-mounted electric device. The LC filter is arranged between the first power converter and the power supply. The LC filter is configured such that the resonance frequency band of the LC filter can be changed. The resonance frequency band of the LC filter is changed based on a ripple amount in a current flowing in the LC filter.

Abstract: A motor-driven compressor includes an electric motor driven by a motor driver, which includes a switching element that converts DC voltage from a battery to AC voltage. A temperature detector detects the temperature of the switching element. A voltage detector detects DC voltage applied to the switching element from the battery. A control unit suspends the switching operation of the switching element when the detected temperature rises to a temperature threshold. The control unit reduces counter electromotive force generated by the electric motor. The controller changes the temperature threshold such that the temperature threshold gradually increases from when the detected DC voltage is the highest voltage in the applicable voltage range of the battery to when the detected DC voltage is the lowest voltage in the applicable voltage range.

Abstract: The control section controls the electric motor to be driven such that the number of revolutions becomes equal to the target number of revolutions. If the control section sets the target number of revolutions to a number of revolutions of the electric motor requested by another control section, the control section changes the number of revolutions of the electric motor at an increase rate lower than or equal to the upper limit value of the increase rate or at a decrease rate lower than or equal to the upper limit value of the decrease rate. If the control section sets the target number of revolutions to a number-of-revolutions limit value, which is determined based on the voltage of a vehicle battery, the control section is able to decrease the number of revolutions of the electric motor at a decrease rate exceeding the upper limit value.

Abstract: An in-vehicle inverter device includes a noise reduction circuit, which has a common mode choke coil configured to reduce common mode noise and normal mode noise contained in DC power, and an inverter circuit, which receives the DC power in which the noise has been reduced. The noise reduction circuit includes: an input-side capacitor and an input-side resistor provided on the input side of the choke coil; an output-side capacitor and an output-side resistor provided on the output side of the choke coil; a first filter circuit that includes the choke coil, the input-side capacitor, and the input-side resistor; and a second filter circuit that includes the choke coil, the output-side capacitor, and the output-side resistor. The first and the second filter circuits reduce leakage noise generated in the inverter circuit.

Abstract: An inverter controller is used to control an inverter circuit that drives an electric motor including a rotor and a stator. The inverter controller includes a voltage detector configured to detect input voltage, a current detector configured to detect motor current, an instruction value calculation unit configured to calculate an instruction value based on an external instruction value and a detection result of the current detector, a correction unit configured to calculate a corrected instruction value by correcting the instruction value in accordance with the input voltage, a PWM control unit configured to control the motor current based on the corrected instruction value and the input voltage, and a position estimation unit configured to estimate a rotation position of the rotor based on the instruction value and the detection result of the current detector.

Abstract: An inverter apparatus includes an inverter circuit, a capacitor, and a control unit. In the first control mode, the control unit shifts a phase of at least one of PWM signals of three phases such that a time period during which polarities of output voltages of three phases are the same is shorter in the first control mode than the time period in the second control mode; and controls the inverter circuit so as to supply a direct current to the three-phase AC motor as a d-axis current by outputting the PWM signals of three phases, each having a phase after the phase shift processing. In the second control mode, the control unit controls the inverter circuit so as to supply an alternating current to the three-phase AC motor by outputting the PWM signals of three phases, each having a phase before the phase shift processing.

Abstract: When the magnitude of a motor current Iu is smaller than a threshold value at a timing when a polarity of the motor current Iu is expected to be reversed after the elapse of one control cycle, a control device sets a correction amount of a width of a pulse generated by PWM control at a correction amount +?. When the magnitude of the motor current is greater than the threshold value at the timing, the control device sets the correction amount of the width of the pulse generated by the PWM control at zero or a value ? smaller than the correction amount +?. As a result, an error of a dead time period in inverter control can be reduced.

Abstract: A motor drive device drives a multi-phase synchronous motor in an electric compressor. The multi-phase synchronous motor includes a rotor that is provided with a permanent magnet and a stator having coils of different phases. The motor drive device includes an inverter that supplies current to the coils and a control unit that controls the inverter. The control unit executes an initial angular position calculation processing of detecting a d-axis and a q-axis as an initial angular position of the rotor, a rotating processing of rotating the d-axis and the q-axis in a direction opposite to rotation of the rotor, an acceleration processing of accelerating the rotation of the rotor, and a sensorless control processing of controlling the rotation of the rotor.

Abstract: A vehicle inverter device is configured to convert DC power to AC power. The vehicle inverter device includes a circuit having switching elements and a noise reducer. The noise reducer is provided on an input side of the circuit and is configured to reduce common mode noise and normal mode noise contained in the DC power. The noise reducer is configured by a common mode choke coil, which includes a core, a first winding wound about a first winding portion of the core, and a second winding wound about a second winding portion of the core.

Abstract: Provided is an inverter apparatus capable of preventing occurrence of overcurrent in an AC motor and stably controlling driving of the AC motor. The inverter apparatus controlling the AC motor included in an electric compressor includes a shunt resistor for detecting current flowing in the AC motor, and a limit value control unit controlling a current limit value for a detected current detected at the shunt resistor. The limit value control unit determines whether the number of times the detected current becomes equal to or more than the first threshold within a first predetermined time is equal to or more than a first number of times. The limit value control unit decreases the current limit value when the number of times the detected current becomes equal to or more than the first threshold within the first predetermined time is equal to or more than the first number of times.

Abstract: A motor-driven compressor includes a compression portion, which compresses a fluid, an electric motor, which drives the compression portion, a drive circuit, which drives the electric motor, a temperature obtaining section, which obtains the temperature of the drive circuit, and a drive mode controller, which controls the drive mode of the drive circuit. The drive mode controller controls the drive mode based on the temperature obtained by the temperature obtaining section and at least one of the rotational speed and the modulation factor of the electric motor.

Abstract: A motor-driven compressor includes an electric motor, a drive circuit, a modulation method controller, a temperature measuring section, a high-temperature (HT) stop controller, and a high-temperature (HT) stop temperature setting section. The high-temperature (HT) stop controller stops the electric motor when the temperature measured by the temperature measuring section is higher than or equal to a predetermined high-temperature (HT) stop temperature. When the modulation method is the three-phase modulation, the HT stop temperature setting section sets the HT stop temperature to a three-phase high-temperature (HT) stop temperature. When the modulation method is the two-phase modulation, the HT stop temperature setting section sets the HT stop temperature to a two-phase high-temperature (HT) stop temperature, which is higher than the three-phase HT stop temperature.

Abstract: An inverter apparatus includes an inverter circuit, a capacitor, and a control unit. In the first control mode, the control unit shifts a phase of at least one of PWM signals of three phases such that a time period during which polarities of output voltages of three phases are the same is shorter in the first control mode than the time period in the second control mode; and controls the inverter circuit so as to supply a direct current to the three-phase AC motor as a d-axis current by outputting the PWM signals of three phases, each having a phase after the phase shift processing. In the second control mode, the control unit controls the inverter circuit so as to supply an alternating current to the three-phase AC motor by outputting the PWM signals of three phases, each having a phase before the phase shift processing.

Abstract: A motor drive device drives a multi-phase synchronous motor in an electric compressor. The multi-phase synchronous motor includes a rotor that is provided with a permanent magnet and a stator having coils of different phases. The motor drive device includes an inverter that supplies current to the coils and a control unit that controls the inverter. The control unit executes an initial angular position calculation processing of detecting a d-axis and a q-axis as an initial angular position of the rotor, a rotating processing of rotating the d-axis and the q-axis in a direction opposite to rotation of the rotor, an acceleration processing of accelerating the rotation of the rotor, and a sensorless control processing of controlling the rotation of the rotor.

Abstract: An electric compressor capable of appropriately starting a motor depending on a condition of a compressing unit is provided. The electric compressor includes: an AC motor including a rotor having a permanent magnet and a stator where a multi-phase coil is wound, and driving a scroll compressor; and an inverter apparatus controlling the AC motor. The inverter apparatus includes: a switching circuit supplying the AC motor with current; and a motor control unit controlling the switching circuit. The motor control unit: measures an elapsed time from a stop to a start of the AC motor for controlling the switching circuit depending on a load on the scroll compressor; calculates a target acceleration of the rotor followed when starting the AC motor, based on the measured elapsed time; and controls the switching circuit so that the rotor is started with the target acceleration.

Abstract: Provided is an inverter apparatus capable of preventing occurrence of overcurrent in an AC motor and stably controlling driving of the AC motor. The inverter apparatus controlling the AC motor included in an electric compressor includes a shunt resistor for detecting current flowing in the AC motor, and a limit value control unit controlling a current limit value for a detected current detected at the shunt resistor. The limit value control unit determines whether the number of times the detected current becomes equal to or more than the first threshold within a first predetermined time is equal to or more than a first number of times. The limit value control unit decreases the current limit value when the number of times the detected current becomes equal to or more than the first threshold within the first predetermined time is equal to or more than the first number of times.