Abstract: An object of the invention is to provide a transistor in which the channel length of the transistor is changed depending on voltages applied to plural gate electrodes which are dividedly formed, and plural kinds of operation states are attained. In a MOS transistor 31, a second gate electrode 36 is formed via an insulating film 35 on a first gate electrode 34 formed in a region E2. The channel length formed in a semiconductor substrate 32 is determined in accordance with the combination of voltages applied to the first and second gate electrodes 34 and 36. The MOS transistor 31 can operate in either of states of different threshold voltages.

Abstract: An electric vehicle torque controller has a torque calculating unit and an actual torque detecting unit. The calculated torque is compared with the actual torque to generate a torque compensation value, which is converted to a torque current signal. The torque current signal is used to generate a slip frequency, which is added to an output of an angular speed detector and used to set a secondary magnetic flux value. A secondary magnetic flux signal is generated according to the secondary magnetic flux value and the torque current signal. A secondary magnetic flux estimating unit generates an estimated secondary magnetic flux value, which is used to determine the exciting current. Primary motor current is controlled in response to the exciting current, the torque current, motor speed and slip value.

Abstract: When a voltage level determinator judges from the terminal voltage of a smoothing capacitance that a battery is in an over-charged state and cannot receive regeneration energy, a regeneration/free-wheel mode selector switches to a free-wheel mode for consuming the energy of the battery. For this purpose, a torque reducing signal generator executes a control in which only a magnetizing component of current flows through the primary winding and no driving force is generated in the motor, with the result that the energy of the battery is consumed as heat loss inside the motor. Then, when the over-charged state is eliminated and the energy receiving capability of the battery is recovered, the regeneration/free-wheel mode selector switches the mode to the regeneration mode to obtain regeneration braking.

Abstract: The object of the present invention is to provide an electric drive system which ensures effective generation of torque from the start to the maximum speed, and extended cruising distance and upgraded running performances. The drive system according to the present invention is characterized in that, in a electric vehicle to be driven by the wheels which are driven by the rotary output of two or more motors, said two or more motors comprise at least two different types of motors, and the system is provided with the control means to adjust the share of the vehicle driving force to be generated by each of said motors in conformity to the running state of said vehicle. These two or more motors comprise a combination of a low speed drive motor and high speed drive motor, and a highly efficient motor is used as said low speed motor, while a motor having a greater capacity and greater base speed than said low speed drive motor is used as the high speed drive motor.

Abstract: An electric vehicle torque controller has a torque calculating unit and an actuate torque detecting unit. The calculated torque signal is compared with the actual torque to generate a torque compensation value, which is converted to a torque current signal. The torque current signal is used to a slip frequency, which is added to the output of an angular speed detector and used to set a secondary magnetic flux value. A secondary magnetic flux signal is generated according to the secondary magnetic flux value and the torque current signal. A secondary magnetic flux estimating unit generates an estimated secondary magnetic flux value, which is used to determine the exciting current. Primary motor current is controlled in response to the exciting current, the torque current, motor speed and slip value.

Abstract: An electric vehicle control system for driving a battery powered motor with use of power inverters. First and second inverters are connected with the respective three-phase primary windings of an induction motor. If one of the inverters fails, failure detection circuits detect it, and a control unit stops the failed inverter and allows the other normal inverter to drive the induction motor to move the electric vehicle. Driving the single motor with a plurality of power inverters allows the electric vehicle to move and run even if one of the power inverters fails.

Abstract: A control apparatus of a motor drive vehicle includes a unit for generating a target vehicle speed; a speed instruction unit for generating a target motor rotational speed of the motor based upon a preset motor control pattern in response to the target vehicle speed; a power circuit for operating the motor at the target motor rotational speed upon receipt of the target motor rotational speed; a variable transmission unit for converting a drive output from the motor into a transmission ratio for instructing a rotational speed of the drive output, and transferring the converted transmission ratio to a drive shaft of the motor drive vehicle; and a transmission ratio calculating unit for determining the transmission gear ratio based on the target vehicle speed and the target motor rotational speed thereby to instruct the determined transmission gear ratio to the variable transmission unit.

Abstract: An electric vehicle control device is disclosed, which includes an AC motor for driving a vehicle; a main electric power conversion unit for supplying an AC voltage to the AC motor; a battery for supplying a DC voltage to the main electric power conversion unit; an auxiliary electric power conversion unit connected to the battery and adapted to be connected to a load or a power supply; a controller for controlling the main and auxiliary electric power conversion units so as to act selectively as an inverter or a converter; and a switching unit for giving selectively the AC motor the AC voltage from the main and auxiliary electric power conversion units under control of the controller. In the running mode of the electric vehicle, the controller described above makes the main electric power conversion unit act as an inverter and controls the switching unit so that the AC voltage from the main electric power conversion unit is given to the AC motor.

Abstract: An electric power steering apparatus for a vehicle comprises a steering shaft, an electric motor operable to generate an auxiliary steering force having a magnitude corresponding to a value of electric current supplied thereto, a steering toque sensor for detecting a steering torque applied to the steering shaft, a vehicle weight sensor for detecting a vehicle weight, and a control device. The control device is constituted to increase and decrease the value of electric current to be supplied to the electric motor in accordance with not only the increase and decrease of the value detected by the steering torque sensor but also the increase and decrease of the value detected by the vehicle weight sensor.

Abstract: An electric power steering control system includes an electric motor for producing an assisting torque for the vehicle steering system through a reduction gear, a steering torque sensor fitted on the steering shaft, a controller for controlling the input to the motor in accordance with the torque sensor output, a battery for supplying power to the controller, and a voltage step-up circuit connected to the battery for driving the motor at a voltage higher than the battery voltage. The controller drives the motor at a high voltage.

Abstract: The steering power assist control comprises a main assist control and an auxiliary assist control. When an abnormality occurrence signal from the main assist control is inputted to an abnormality state detection and changing decision circuit 134, the selector circuit changes the PWM signal from the main assist control side to the auxiliary assist control side and outputs the PWM signal to a motor drive circuit. When the main assist control fails, the auxiliary assist control immediately takes over the main assist control to provide, if the operation condition permits, a continued steering power assist control. This prevents an abnormal steering state of the vehicle that would otherwise result when the steering power assist is suddenly lost.

Abstract: A vehicle height control apparatus responsive to power steering operation is disclosed in which a torque signal indicative of the steering torque imparted to the steering wheel by a driver's operation thereof is used for controlling the power steering system and also for controlling the operation of actuators for adjusting damping force of shock absorber provided to each wheel thereby controlling the height of the vehicle.

Abstract: A counter is provided to count an output pulse which a pulse generator generates each time a vehicle moves by a predetermined distance. A microprocessor is provided to actuate a timer in synchronism with the leading edges of the output pulse from the pulse generator. The timer is set to a constant time interval during which the speed of the vehicle is to be detected. The microprocessor calculates the speed of the vehicle from the count of the counter which count is a value during the time interval from when the timer starts to operate to when the pulse generator generates a pulse just before or after the end point of the set time interval. Thus, the speed of the vehicle can be detected with good resolution and precision.

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.

Abstract: A power switching apparatus for use in the control of a D.C. load such as a D.C. motor comprises a power transistor with its emitter-collector path connected in series with the D.C. motor and a battery. A base current of the power transistor is supplied from the battery through a controllable impedance element. A control unit is provided to vary the impedance of the controllable impedance element in response to the current flowing through the emitter-collector path in such a manner that the base current changes as substantially the inverse-function of a characteristic curve indicating a D.C. amplification factor versus collector current of the power switch transistor.

Abstract: An automatic change-gear control device for use in an electromobile which incorporates a multi-stage change gear drive system. This automatic change gear control device selects and controls a gear ratio for an optimum ratio, depending on the running condition of a vehicle, and particularly provides a change-gear logic by detecting a load torque for every individual condition, in an attempt to improve the running performance of a vehicle at the time of acceleration or at the time of running on an upward slope.

Abstract: A system is disclosed for controlling the speed and torque of an electric motor throughout its entire operating range from low speed operation to high speed operation, while minimizing the total loss of energy in the motor. The minimization of energy loss is facilitated by controlling the motor field current during the low running speed of the motor as well as during the high running speed.