Kabushiki Kaisha Meidensha

Tadashi Ashikaga

Takayuki Mizuno

Masakatsu Nomura

Kenji Yamada

Masayuki Terashima

Kazutoshi Nagayama

Yoshihide Kamanaka

Takafumi Hashimoto

Yoshihiro Murai

Keiko Suda

Isao Matsuda

Katsuyuki Watanabe

Masato Mori

Tadashi Ichioka

Kouhei Ohnishi

Michitaka Hori

Keiko Fushimi

An apparatus for a pole change induction motor and control method for the same which are applicable to, for example, a driving source of an electric vehicle without power transmission are disclosed. In the control apparatus and method for the pole change motor is electrically changed between an n number of poles and a 2n number of the poles (n=2, 4, - - - ) so as to secure an output torque of the pole change induction motor in a constant driving mode with a high rotation speed of the induction motor without increase in a dimension of either of the induction motor or an inverter associated with the pole change induction motor and without occurrence in a torque variation. In a preferred embodiment, two channels of exciting and torque instructions and slip frequency generators (current instruction calculating blocks and current control systems) are provided for the n number of pole driving and 2n number of pole driving.

Pole change induction motor and control apparatus and method for the same

In a drive circuit for a switched reluctance motor, a DC power supply is provided, a plurality of main circuit switching devices cause branched currents from a current derived from the DC power supply to flow through stator windings of the switched reluctance motor sequentially during their turned on states; a plurality of freewheel diodes are provided, each connected across a corresponding one of the main circuit switching devices in a reverse parallel connection; a plurality of reverse flow blocking diodes are provided, each cathode of which is connected to an output end of the corresponding one of the main circuit switching devices; a resonance purpose capacitor is provided whose one end is connected to a plus terminal of the DC power supply via a resistor and whose other end is connected to an anode of each reverse flow blocking diode; a serial circuit is connected across the resonance purpose capacitor and is constituted by a resonance purpose inductor and a resonance purpose switching device for causing the resonance purpose inductor and capacitor to be resonated when turned on at a time point at which it comes near an end of a turn on interval of time of each main circuit switching device; and a bypass diode is provided whose anode is connected to a minus terminal of the DC power supply and whose cathode is connected to the one end of the resonance purpose capacitor.

Drive circuit for switched reluctance motor

To extend an operable range of a hybrid excitation type permanent magnet synchronous motor having a field of a permanent magnet and a dc excitation coil, magnetic flux of the field is controlled so as to keep constant when a rotation speed of the motor is smaller than a predetermined base speed and so as to change in reverse proportion with the rotation speed of the motor when the rotation speed is larger than the predetermined base speed. Electric current and voltage to an armature of the motor is controlled such that a current ratio of a direct-axis component and a quadrature-axis component which components are obtained by dividing an electric current to the armature coil into the direct-axis component and the quadrature-axis component relative to the voltage induced in the armature coil, is kept constant.

Method and apparatus for controlling hybrid excitation type permanent

A motor speed control system takes one approach to establish dummy load models having characteristics equivalent to an electric motor to be controlled. One of the dummy load models is established for feedback controlling the electric motor on the basis of the speed of the dummy model. The dummy model is divided into first and second models. The first model is designed to have equivalent characteristics to output a first motor speed representative data. The current to supply to the first model is so adjusted as to reduce a difference between the motor speed representative data and a desired motor speed data to zero. A frequency signal is added to the current applied to the first model and supplied to the electric motor to drive the latter. The second model receives the frequency signal to output a frequency signal dependent second motor speed representative value. Sum of the first and second motor speed representative value is compared with a measured motor speed indicative value to derive a speed difference compensation value based on the error therebetween. Based on the speed difference between the sum value and the measured motor speed and the frequency signal, inertia condition on the motor is assumed for controlling transfer characteristics so that the inertia condition in the first model becomes coincident with that of the motor.

Control system for controlling revolution speed of electric motor

A method and apparatus for vector control of an induction motor. A slip frequency is calculated based on a desired motor torque, a desired motor flux and a motor secondary time constant. An actual value for induction motor angular velocity is estimated as a function of primary current and voltage applied to drive the induction motor. The calculated slip frequency is added to the estimated angular velocity to calculate an angular frequency. The calculated angular frequency is used along with the desired motor torque and the desired motor flux to vary the primary current and voltage so as to drive the induction motor with no .beta.-axis secondary flux.

Induction motor vector control

An induction motor vectro control apparatus calculates a slip factor using a secondary time constant. A reference signal is added as noise to the excitation current command signal. The secondary time constant is brought closer to its actual value by modifying the secondary time constant in a direction zeroing the correlation between the motor speed feedback signal and the reference signal.

Induction motor control apparatus

A secondary battery operating method for charging and discharging a secondary battery using zinc as the negative electrode active material. After the termination of the normal discharge, direct current supply means is connected to the secondary battery in opposite polarity relation with each other and the secondary battery is reverse charged in a polarity opposite to the normal polarity. As a result of this reversed charge, the zinc remaining on the negative electrode after the termination of the normal discharge is completely dissolved into the electrolyte. If necessary, the energy stored in the secondary battery after the termination of the normal discharge is regenerated during the reversed charge.

Method of operating a secondary battery to recondition the battery

Plural series of digital pattern data are determined by PWMing a sine wave by a triangular wave and further classified into each series by the number of triangles included within a half cycle of the sine wave. An appropriate series of data are selected according to a frequency command. The selected data are further adjusted in response to a voltage control command. On the basis of the selected and adjusted pattern data and in response to a half period signal of triangular wave and triangle slope signals, a PWMed pulse is generated through a logical circuit. In the case where the generator is incorporated with an induction motor driving system, it is possible to control speed (frequency), torque (voltage), rotational directions, and torque fluctuations (phase difference) of an induction motor accurately at high response speed.

Digital PWMed pulse generator

In a vector control method and system for an induction motor, the decoupling calculation and 2-3 phase transformation are combined to simplify the system configuration, and the plus and minus signs of trigonometric signals are changed according to the rotational direction to enable four-quadrant operation. Further, in the case of a 3-phase induction motor driven by a PWM inverter, the number of the triangular (carrier) wave signals generated during one period of the power supply signal is increased with decreasing frequency of the supply voltage signal to improve the response characteristics when the motor is rotating at a low speed. Furthermore, an initial supply voltage signal with a predetermined frequency is applied to the triangular wave signal generator, when the motor stops, to generate an initial secondary magnetic flux before starting the motor.

Vector control method and system for an induction motor

In a vector control method and system for an induction motor, the decoupling calculation and 2-3 phase transformation are combined to simplify the system configuration, and the plus and minus signs of trigonometric signals are changed according to the rotational direction to enable four-quadrant operation. Further, in the case of a 3-phase induction motor driven by a PWM inverter, the number of the triangular (carrier) wave signals generated during one period of the power supply signal is increased with decreasing frequency of the supply voltage signal to improve the response characteristics when the motor is rotating at a low speed.

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Tokyo, Japan

Tadashi Ashikaga