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: A power conversion device includes: an inverter that converts a DC current supplied from a DC power source to an AC current by engaging a plurality of switching elements, which constitute an upper arm, and a plurality of switching elements, which constitute a lower arm, in switching operation; a control unit that includes a signal generation unit that generates a switching signal carrying a command for execution of the switching operation in correspondence to each of the plurality of switching elements constituting the upper arm and the plurality of switching elements constituting the lower arm, and outputs the switching signal thus generated as a control signal; and a drive unit that individually drives each of the switching elements based upon the corresponding control signals.

Abstract: A discharge circuit for a DC power supply smoothing capacitor that is used in a power conversion device that supplies DC power via a switch to the DC power supply smoothing capacitor and an inverter, includes; a resistor that discharges charge in the capacitor; a switch connected in series with the resistor, that either passes or intercepts discharge current flowing from the capacitor to the resistor; a measurement circuit that measures a terminal voltage of the capacitor; and a control circuit that controls continuity and discontinuity of the switch; wherein the control circuit, after having made the switch continuous and starting discharge of the capacitor by the resistor, if a terminal voltage of the capacitor as measured by the measurement circuit exceeds a voltage decrease characteristic set in advance, makes the switch discontinuous and stops discharge by the resistor.

Abstract: An electrical power conversion device includes: a switching element in which a principal electrical current flows in a direction from a second electrode towards a first electrode based upon a voltage being applied to a control electrode; a voltage control circuit that controls the voltage that is applied to the control electrode; and a continuity control circuit that is connected between the second electrode and the control electrode and controls continuity between the second electrode and the control electrode.

Abstract: An electrically-operated power steering control system is disclosed for an electrically-operated power steering apparatus in which a motor is controlled in accordance with a predetermined function of the steering power applied to a steering wheel and an auxiliary steering power is supplied by this motor. The motor is controlled on the basis of a conduction ratio which is modified depending on a comparison between a change of a detected torque signal of a torque sensor and the rate of change of the steering angle.

Abstract: A device for detecting a load torque using angle detectors fitted with a certain spacing on a shaft which is rotated by a drive source and on the basis of a relative angular difference of angles detected by the angle detectors. The device includes two rotary drums or discs fitted with a certain spacing on the drive side and load side of the shaft, with a plurality of magnetic poles for generating magnetic signals being formed on the surface thereof, and a magnetic sensor disposed to confront the surface of the rotary drums or discs, with magnetic resistance effect elements which vary in internal resistance in response to the magnetism of the magnetic poles being provided thereon. The amount of torsion created by the load on the load side of the rotary shaft is measured as a phase difference of outputs of the magnetic sensor, and the torque is detected in terms of the angular difference between the magnetic drums or discs.

Abstract: A control system for a power steering apparatus having a steering wheel angle detection device comprising a steering angle sensor for generating reference pulses at a plurality of steering wheel angle positions, including a neutral position of a steering wheel, and generating angle pulses as the steering wheel is rotated, an up/down counter for counting up or down the angle pulses supplied from the steering angle sensor depending on the direction of rotation of the steering wheel, and a vehicle velocity sensor for detecting the vehicle velocity. When the vehicle velocity detected by the vehicle velocity sensor is higher than a predetermined velocity and a reference pulse is detected by the steering angle sensor which is determined to be a steering wheel straight ahead position then the up/down counter is reset to zero.

Abstract: An electro-motive power steering system includes a torque sensor for detecting a steering force exerted to a steering wheel, a motor controlled in accordance with the output of the torque sensor, a steering angle sensor for detecting a steering angle, acceleration/deceleration deciding circuit for deciding based on the outputs of the torque sensor and the steering angle sensor whether the steering of the steering wheel is accelerated or decelerated, and a function generator for generating a function of either one of acceleration or deceleration in accordance with the result of the decision by the acceleration/deceleration deciding circuit, wherein a steering assisting force corresponding to the acceleration or deceleration of the steering of the steering wheel is applied to the steering wheel.

Abstract: A power steering control apparatus includes apparatus for detecting a steering force applied to a steering wheel of a vehicle, an actuator controllable in accordance with an output of the steering force detecting apparatus and apparatus for detecting a steering angle, and the actuator is controlled in accordance with the steering angle and the steering force such that an assistant restoring force corresponding to the steering angle is applied to the steering wheel.

Abstract: A control apparatus for electric vehicles by using a chopper circuit which turns on or off a d-c drive motor responsive to the instruction of a microcomputer.The control apparatus of the present invention is characterized by the provision of a protection device. The protection device comprises means for generating a predetermined signal, means for adding the predetermined signal to a signal which varies depending upon the stepped-in amount of the accelerator pedal, means for comparing the added signal with an output signal of a current detector which detects a current that flows into the d-c drive motor, and means which sets the microcomputer when the output signal of the current detector is greater than the added signal and which permits the microcomputer to start again its operation after a predetermined period of time has passed.