Abstract: A motor current detecting device includes a first wire, an instantaneous current detecting unit, an average electric current detecting unit, and a calculation unit. The first wire is configured and arranged to carry flow of a motor current that has been passed through a motor and a drive current that has been passed through a motor drive unit to drive the motor. The instantaneous current detecting unit is configured and arranged to detect an instantaneous value for a sum of the motor current and the drive current flowing on the first wire. The average electric current detecting unit is configured and arranged to detect an average value of the sum of the motor current and the drive current flowing on the first wire. The calculation unit is configured to calculate the motor current on the basis of the instantaneous value and the average value.

Abstract: When an abnormality occurs in a refrigeration cycle, the inverter motor provided in the air conditioner is stopped reliably and contacts of the main relay are prevented from degradation and fusion. A power circuit 1 of the air conditioner includes a rectifier circuit RC, a capacitor C (smoothing unit), a main relay 10 provided on a current path between the rectifier circuit RC and the capacitor C, an inverter circuit 30, a microcomputer 100, and a delay circuit 40. The microcomputer 100 has an inverter circuit control unit 110, a main relay opening/closing control unit 120, a waveform forced cut-off unit 130, and a cut-off signal output unit 140.

Abstract: Triggered by a position detection sensor detecting that a rotor is positioned at any one of K predetermined electrical angles, for example, 60°, 180°, and 300°, a voltage vector to be given to a motor is updated. When, for example, the rotation frequency is equal to or higher than a specified value, the predetermined electrical angles is changed into M, for example, into one angle of 60°.

Abstract: A current detecting device includes a current leveling unit, a first wire and a current detecting unit. The current leveling unit is configured to level a drive current that is passed through a motor drive unit to drive a motor. The first wire is configured and arranged to carry flow of a motor current that has been passed through the motor and the drive current that has been leveled by the current leveling unit. The current detecting unit is configured to detect a sum of the motor current flowing on the first wire and the drive current that has been leveled flowing on the first wire.

Abstract: An increase in a ripple voltage of a capacitor in a smoothing circuit is prevented to achieve a compact capacitor and cost reduction for capacitors in an electric power supply circuit which performs PAM control using a switching element. An electric power supply circuit includes a bridge circuit for rectifying alternating current power, a smoothing circuit which has two capacitors serially connected to each other, and a PAM control section for turning a switching element on and off at a predetermined timing. The PAM control section includes a phase difference detection section which detects a phase shift of a PAM waveform based on a change in a voltage difference between the two capacitors, and a phase correction section which corrects the phase of the PAM waveform so that an input current has a sine waveform.

Abstract: The invention relates to a power conversion apparatus including a converter circuit and an inverter circuit. The invention allows more precise output control of the inverter circuit than a power conversion apparatus in which the output control is performed based on a current value only, thereby improving operation efficiency. A current sensor detects input current of the inverter circuit, and a voltage sensor detects input voltage of the inverter circuit. A power value calculator section in an inverter microcomputer obtains a power value based on the input current and the input voltage. The inverter microcomputer and the control microcomputer perform droop control of reducing the output of the inverter circuit to make the power value smaller than a predetermined power value.

Abstract: An electric power supply circuit includes a switching element (S) for causing a short-circuit for output power of a diode bridge circuit (12), a zero-cross detector section (5a) for detecting a point at which an input voltage reaches a level equal to or lower than a reference level, a timer section (5d) for starting a count upon the detection by the zero-cross detector section (5a), and a PAM waveform output section (5c) for causing the switching element (S) to perform switching with a predetermined output timing so that a waveform of the input current is caused to approximate to a sine wave. The circuit further includes a correction section (5e) for correcting, when a difference between a detection interval from detection to detection by the zero-cross detector section (5a), and an average value for detection intervals up to current detection occurs, an initial value of the count of the timer section (5d) according to the difference.

Abstract: The power supply device according to the present invention converts alternating-current power into direct-current power, and supplies the direct-current power to a load. Further, the power supply device includes a buffer, a control section, a rectifier circuit, a smoothing circuit, and a switch. After a predetermined zero cross point is detected, the control section uses in common, over a predetermined period of the alternating-current power, predetermined parameters retained in the buffer in calculating a timing at which a PAM interrupt pulse is generated.

Abstract: A boot capacitor that functions as an operating power supply for a high-arm-side transistor provided in an inverter has to be charged prior to normal operation of a motor. This operation of charging the boot capacitor is performed at a carrier frequency that is lower than a carrier frequency for the normal operation.

Abstract: When an abnormality occurs in a refrigeration cycle, the inverter motor provided in the air conditioner is stopped reliably and contacts of the main relay are prevented from degradation and fusion. A power circuit 1 of the air conditioner includes a rectifier circuit RC, a capacitor C (smoothing unit), a main relay 10 provided on a current path between the rectifier circuit RC and the capacitor C, an inverter circuit 30, a microcomputer 100, and a delay circuit 40. The microcomputer 100 has an inverter circuit control unit 110, a main relay opening/closing control unit 120, a waveform forced cut-off unit 130, and a cut-off signal output unit 140.

Abstract: An electric power supply circuit includes a diode bridge circuit (12) for rectifying an alternating current, a switching element (S) for causing a short-circuit for output power of the diode bridge circuit (12), and a PAM control section (15) for causing the switching element (S) to perform switching with a predetermined timing so that a waveform of an input current approximates to a sine wave. The PAM control section (15) outputs ON/OFF pulses so that five pulses are output for each zero-cross point and one of the five pulses located in center extends over the zero-cross point at any time.

Abstract: The invention relates to a power conversion apparatus including a converter circuit and an inverter circuit. The invention allows more precise output control of the inverter circuit than a power conversion apparatus in which the output control is performed based on a current value only, thereby improving operation efficiency. A current sensor detects input current of the inverter circuit, and a voltage sensor detects input voltage of the inverter circuit. A power value calculator section in an inverter microcomputer obtains a power value based on the input current and the input voltage. The inverter microcomputer and the control microcomputer perform droop control of reducing the output of the inverter circuit to make the power value smaller than a predetermined power value.

Abstract: Triggered by a position detection sensor detecting that a rotor is positioned at any one of K predetermined electrical angles, for example, 60°, 180°, and 300°, a voltage vector to be given to a motor is updated. When, for example, the rotation frequency is equal to or higher than a specified value, the predetermined electrical angles is changed into M, for example, into one angle of 60°.

Abstract: A motor current calculation device includes a first wire, a current detecting unit, a decision unit, and a calculation unit. The first wire is configured and arranged to carry flow of a motor current that has been passed through a motor and a drive current that has been passed through a motor drive unit to drive the motor. The current detecting unit is configured and arranged to detect a sum of the motor current and the drive current flowing through the first wire. The decision unit is configured and arranged to determine a first detection result of the current detecting unit when the motor is not rotating as the drive current. The calculation unit is configured to calculate the motor current by subtracting the drive current determined by the decision unit from a second detection result of the current detecting unit when the motor is rotating.

Abstract: A motor current detecting device includes a first wire, an instantaneous current detecting unit, an average electric current detecting unit, and a calculation unit. The first wire is configured and arranged to carry flow of a motor current that has been passed through a motor and a drive current that has been passed through a motor drive unit to drive the motor. The instantaneous current detecting unit is configured and arranged to detect an instantaneous value for a sum of the motor current and the drive current flowing on the first wire. The average electric current detecting unit is configured and arranged to detect an average value of the sum of the motor current and the drive current flowing on the first wire. The calculation unit is configured to calculate the motor current on the basis of the instantaneous value and the average value.

Abstract: A boot capacitor that functions as an operating power supply for a high-arm-side transistor provided in an inverter has to be charged prior to normal operation of a motor. This operation of charging the boot capacitor is performed at a carrier frequency that is lower than a carrier frequency for the normal operation.

Abstract: A current detecting device includes a current leveling unit, a first wire and a current detecting unit. The current leveling unit is configured to level a drive current that is passed through a motor drive unit to drive a motor. The first wire is configured and arranged to carry flow of a motor current that has been passed through the motor and the drive current that has been leveled by the current leveling unit. The current detecting unit is configured to detect a sum of the motor current flowing on the first wire and the drive current that has been leveled flowing on the first wire.

Abstract: An increase in a ripple voltage of a capacitor in a smoothing circuit is prevented to achieve a compact capacitor and cost reduction for capacitors in an electric power supply circuit which performs PAM control using a switching element. An electric power supply circuit includes a bridge circuit (12) for rectifying alternating current power, a smoothing circuit (13) which has two capacitors (C1 and C2) serially connected to each other, and a PAM control section (15) for turning a switching element (S) on and off at a predetermined timing. The PAM control section (15) includes a phase difference detection section (15d) which detects a phase shift of a PAM waveform based on a change in a voltage difference between the two capacitors (C1 and C2), and a phase correction section (15e) which corrects the phase of the PAM waveform so that an input current has a sine waveform.

Abstract: An electric power supply circuit includes a switching element (S) for causing a short-circuit for output power of a diode bridge circuit (12), a zero-cross detector section (5a) for detecting a point at which an input voltage reaches a level equal to or lower than a reference level, a timer section (5d) for starting a count upon the detection by the zero-cross detector section (5a), and a PAM waveform output section (5c) for causing the switching element (S) to perform switching with a predetermined output timing so that a waveform of the input current is caused to approximate to a sine wave. The circuit further includes a correction section (5e) for correcting, when a difference between a detection interval from detection to detection by the zero-cross detector section (5a), and an average value for detection intervals up to current detection occurs, an initial value of the count of the timer section (5d) according to the difference.

Abstract: The power supply device according to the present invention converts alternating-current power into direct-current power, and supplies the direct-current power to a load. Further, the power supply device includes a buffer, a control section, a rectifier circuit, a smoothing circuit, and a switch. After a predetermined zero cross point is detected, the control section uses in common, over a predetermined period of the alternating-current power, predetermined parameters retained in the buffer in calculating a timing at which a PAM interrupt pulse is generated.