Abstract: An inverter drive device includes a drive circuit that outputs a gate voltage signal of a power semiconductor element; and a Zener clamping protection circuit that acquires an emitter electrode side voltage of the power semiconductor element, and, if that voltage is greater than a predetermined voltage value, performs clamping of the gate voltage of the drive circuit after a predetermined time interval has elapsed from the acquisition of the emitter electrode side voltage. The Zener clamping protection circuit includes a latch circuit that, after the emitter electrode side voltage has been acquired, continues the clamping of the gate voltage by the Zener clamping protection circuit during an interval.

Abstract: An overcurrent fault detection device includes: an inverter converting DC current to three-phase AC currents for driving a motor; a DC voltage detector; phase current detectors; a rotational position detector that detects a rotational angle of the motor; a control circuit that controls a gate drive circuit, which controls the inverter at every predetermined cycle, based upon the phase current values, a motor rotational angle detection value, and a speed command or a torque command from a higher-order control device; and a decision-making circuit that detects an overcurrent based upon the phase current values at every predetermined cycle, wherein: the decision-making circuit determines whether or not the phase current values exceed a predetermined amplitude threshold value by frequency detection for any of the phase current values exceeding the predetermined amplitude threshold value, and determines that an overcurrent has occurred upon detecting the frequency.

Abstract: According to the present invention, an overcurrent fault detection device includes: an inverter converting DC current to three-phase AC currents for driving a motor; a DC voltage detector; phase current detectors; a rotational position detector that detects a rotational angle of the motor; a control circuit that controls a gate drive circuit, which controls the inverter at every predetermined cycle, based upon the phase current values, a motor rotational angle detection value, and a speed command or a torque command from a higher-order control device; and a first decision-making circuit that detects an overcurrent based upon the phase current values at every predetermined cycle, wherein: the first decision-making circuit determines whether or not the phase current values exceed a predetermined amplitude threshold value by frequency detection for any of the phase current values exceeding the predetermined amplitude threshold value, and determines that an overcurrent has occurred upon detecting the frequency.

Abstract: A power conversion system according to the present invention includes: an inverter circuit unit that converts a direct current power supplied from a direct current source into an alternating current power, the direct current power being supplied to the inverter circuit through a contactor that conducts and interrupts the direct current; a capacitor that smoothes the direct current power; a discharge circuit unit that is connected to the capacitor in parallel, and that includes a discharge resistor for discharging a charge stored in the capacitor and a switching element for the discharge resistor, being connected in series to the discharge resistor; a voltage detection circuit unit that detects voltage between both terminals of the capacitor; a first discharge control circuit that includes a first microcomputer, and that outputs a control signal to control switching of the switching element for discharging; and a second discharge control circuit that outputs an interruption signal to interrupt the switching el

Abstract: An inverter drive device includes a drive circuit that outputs a gate voltage signal of a power semiconductor element; and a Zener clamping protection circuit that acquires an emitter electrode side voltage of the power semiconductor element, and, if that voltage is greater than a predetermined voltage value, performs clamping of the gate voltage of the drive circuit after a predetermined time interval has elapsed from the acquisition of the emitter electrode side voltage. The Zener clamping protection circuit includes a latch circuit that, after the emitter electrode side voltage has been acquired, continues the clamping of the gate voltage by the Zener clamping protection circuit during an interval.

Abstract: According to the present invention, an electrical power conversion system includes: a motor; an inverter circuit that outputs three-phase (U-phase, V-phase, W-phase) alternating currents to the motor; a current sensor that detects each of the three-phase alternating currents; and a control circuit that controls the inverter circuit based on a torque command value and values detected by the current sensor, so that the three-phase alternating currents outputted from the inverter circuit are formed as sine waves; and wherein the control circuit includes: a current component extraction unit that, based on the values detected by the current sensor, for each phase, extracts current components superimposed upon each of three-phase alternating currents; and an AC current abnormality detection unit that detects abnormality of an AC current flowing to the motor, based on the phases of the current components for any two phases among the three-phase alternating currents.

Abstract: The present invention provides a power converter including a power semiconductor device, a driver circuit section that outputs a driving signal for driving the power semiconductor device, a buffer circuit section that includes a PNP transistor and an NPN transistor and that outputs a gate voltage for driving the power semiconductor device, a first delay circuit section that receives the driving signal and that generates a first delay signal on the basis of the received driving signal, a first MOSFET that has a drain electrode connected with the output of the buffer circuit section and that is driven on the basis of the first delay signal.

Abstract: Connection portions (225UP through 225WP) to which upper arm control terminals (320UU through 320UW) are connected are disposed at a first edge portion of a drive circuit board (22). And connection portions (225UN through 225WN to which lower arm control terminals (320LU through 320LW) are connected are disposed at a second edge portion of the drive circuit board (22). Upper arm implementation regions (227UP through 227WP), lower arm implementation regions (227UN through 227WN), and a low voltage pattern region (228) in which photo-couplers (221U through 221W) are implemented are formed in the board region between these board edge portions. And signal wiring (40U) that transmits a control signal from a photo-coupler (221U) to an implementation region (227UN) is formed in a conductor layer that is a lower layer than the conductor layer in the lower arm implementation region in which the lower arm driver circuit is implemented.

Abstract: According to the present invention, an overcurrent fault detection device includes: an inverter converting DC current to three-phase AC currents for driving a motor; a DC voltage detector; phase current detectors; a rotational position detector that detects a rotational angle of the motor; a control circuit that controls a gate drive circuit, which controls the inverter at every predetermined cycle, based upon the phase current values, a motor rotational angle detection value, and a speed command or a torque command from a higher-order control device; and a first decision-making circuit that detects an overcurrent based upon the phase current values at every predetermined cycle, wherein: the first decision-making circuit determines whether or not the phase current values exceed a predetermined amplitude threshold value by frequency detection for any of the phase current values exceeding the predetermined amplitude threshold value, and determines that an overcurrent has occurred upon detecting the frequency.

Abstract: A power conversion system according to the present invention includes: an inverter circuit unit that converts a direct current power supplied from a direct current source into an alternating current power, the direct current power being supplied to the inverter circuit through a contactor that conducts and interrupts the direct current; a capacitor that smoothes the direct current power; a discharge circuit unit that is connected to the capacitor in parallel, and that includes a discharge resistor for discharging a charge stored in the capacitor and a switching element for the discharge resistor, being connected in series to the discharge resistor; a voltage detection circuit unit that detects voltage between both terminals of the capacitor; a first discharge control circuit that includes a first microcomputer, and that outputs a control signal to control switching of the switching element for discharging; and a second discharge control circuit that outputs an interruption signal to interrupt the switching el

Abstract: According to the present invention, an electrical power conversion system includes: a motor; an inverter circuit that outputs three-phase (U-phase, V-phase, W-phase) alternating currents to the motor; a current sensor that detects each of the three-phase alternating currents; and a control circuit that controls the inverter circuit based on a torque command value and values detected by the current sensor, so that the three-phase alternating currents outputted from the inverter circuit are formed as sine waves; and wherein the control circuit includes: a current component extraction unit that, based on the values detected by the current sensor, for each phase, extracts current components superimposed upon each of three-phase alternating currents; and an AC current abnormality detection unit that detects abnormality of an AC current flowing to the motor, based on the phases of the current components for any two phases among the three-phase alternating currents.

Abstract: Connection portions (225UP through 225WP) to which upper arm control terminals (320UU through 320UW) are connected are disposed at a first edge portion of a drive circuit board (22). And connection portions (225UN through 225WN to which lower arm control terminals (320LU through 320LW) are connected are disposed at a second edge portion of the drive circuit board (22). Upper arm implementation regions (227UP through 227WP), lower arm implementation regions (227UN through 227WN), and a low voltage pattern region (228) in which photo-couplers (221U through 221W) are implemented are formed in the board region between these board edge portions. And signal wiring (40U) that transmits a control signal from a photo-coupler (221U) to an implementation region (227UN) is formed in a conductor layer that is a lower layer than the conductor layer in the lower arm implementation region in which the lower arm driver circuit is implemented.

Abstract: A power converter unit comprises: a metal casing; a power module mounted in the metal casing and equipped with two or more power semiconductor devices; a metal plate disposed on the power module and fixed to the metal casing; a heat dissipating sheet disposed on the metal plate; and a drive circuit board disposed on the heat dissipating sheet and is equipped with a control circuit for controlling the power semiconductor devices.

Abstract: A power converter unit has a metal case; a power module having a plurality of power semiconductor devices that is provided inside the metal case; a gate drive circuit board having a circuit for driving the plurality of the power semiconductor devices that is mounted on the power module; a voltage sensor that is mounted on the gate drive circuit board; a metal plate for electrically connecting the metal case with the gate drive circuit board; screws and soldered parts for fixing the metal plate to the gate drive circuit board; a first wiring that is set up on the gate drive circuit board for electrically connecting the voltage sensor with the soldered parts; and a second wiring that is set up on the gate drive circuit board for electrically connecting the screws and the soldered parts.

Abstract: A power converter unit comprises: a metal casing; a power module mounted in the metal casing and equipped with two or more power semiconductor devices; a metal plate disposed on the power module and fixed to the metal casing; a heat dissipating sheet disposed on the metal plate; and a drive circuit board disposed on the heat dissipating sheet and is equipped with a control circuit for controlling the power semiconductor devices.