Abstract: An AC-DC converter includes an adjusting unit 13 which operates to zero the difference between a DC output voltage instruction value and a DC output voltage detection value; and a modulator 16 which compares a carrier wave based on an output signal of the adjusting unit 13 with a modulating wave to output drive pulses, a switching element 3 is turned on and off with the drive pulses to provide a DC output voltage which is higher than a full-wave rectification voltage of an AC input voltage. In order to obtain the carrier wave, the AC-DC comprises further includes an AC input voltage polarity detector 7, a PLL circuit 11, and a multiplier 14 for multiplying the sine wave by an output signal of the adjusting unit 13.

Abstract: A magnet rotor for a synchronous motor includes a yoke formed of a magnetic material. A generally cylindrical permanent magnet is disposed around the yoke magnet and has N and S poles alternately located in the circumferential direction of the permanent magnet. An adhesive is filled in the clearance between the outer peripheral surface of the yoke and the inner peripheral surface of the permanent magnet. The adhesive is hardened at a hardening temperature, which is around a maximum temperature encountered during operation of the motor to accomplish bonding between the yoke and the permanent magnet. The clearance between the yoke and the permanent magnet has a dimension L given by the following formula:L.gtoreq.(E.times..DELTA.L) / .sigma.swhere E is a tensile elastic modulus of the adhesive; .DELTA.L is a change amount of the clearance upon thermal expansion or contraction; and .sigma.s is a tensile stress applied to the adhesive.

Abstract: A driving device controls a permanent-magnet synchronous motor having a permanent magnet in its rotor using a voltage-type inverter supplying drive power for the synchronous motor, makes the torque of the synchronous motor and the d-axis current flowing in the synchronous motor in the direction of the magnetic flux generated by the permanent magnet approach their own command values, and performs weakening field control by decreasing the d-axis current. To perform the above described control without complicated d-axis current command value operations or temperature amendments to motor constants, the driving device includes a proportional controller for outputting a d-axis signal proportional to the deviation between a d-axis current detection value and a d-axis current command value for the motor.

Abstract: An inverter converting by using semiconductor power switching devices a DC voltage supplied from a main battery to an AC voltage supplied to an AC motor. Unipolar switching devices such as MOSFETs are used as the power switching devices. The power switching devices are controlled so that the output voltage of the inverter is composed of pulses taking three levels in the operation range of high output power. This makes it possible to reduce the stationary loss and switching loss of the switching devices, and to increase the efficiency of the inverter.

Abstract: A control circuit for controlling a power converting apparatus, maintaining a stable operation of an induction motor. The control circuit includes an exciting current obtaining circuit which obtains the exciting current component from a detected signal of primary currents of the induction motor, a circuit which obtains an exciting current oscillation component from the exciting current correlate, a circuit which obtains correcting quantity from the exciting current oscillation component, and circuits which correct the voltage command or the flux command by the correcting quantity, and provide it to the power converting apparatus as stator axis voltage command values.

Abstract: In an electric system for an electric vehicle, DC power of a main battery is converted into AC power by an inverter which has a power regenerative function. At startup, the system charges an input smoothing capacitor on the DC side of the inverter through an initial charging circuit with an initial charging switch and resistor. A main circuit switch that can stop current is connected between the main battery and the inverter. A rheostatic braking circuit with a rheostatic braking switch and a braking resistor is connected to the DC input side of the inverter for rheostatic breaking when required. Rheostatic braking takes over after regenerative braking when the main battery loses its power absorption capability, with the main circuit switch off. Semiconductors can be used as switches, and can be placed on a cooling body or modularized. Low-noise wires can be used to reduce noise.

Abstract: An AC variable speed driving apparatus including an AC motor and an inverter for driving the motor. The AC motor includes a synchronous motor and an induction motor. The synchronous motor includes first stator windings and a first rotor having a permanent magnet. The induction motor includes second stator windings and a second rotor. The first and second stator windings are disposed so that they do not magnetically interfere with each other. The first and second rotors are mounted on a common axis of rotation. The inverter supplies AC power to the stator windings so that the synchronous motor and the induction motor are driven independently. A highly efficient, large output and low cost system can be realized in a wide speed range.

Abstract: An electric system for an electric vehicle includes a main battery used for driving the vehicle, an auxiliary battery used for accessories of the vehicle, an AC motor for driving one or more wheels, an inverter for converting DC power supplied from the main battery to AC power to be supplied to the AC motor, and an auxiliary battery charging circuit for charging the auxiliary battery by using the AC power from the inverter. When charging the auxiliary battery, the AC power is insulatedly transformed and then rectified. In another example, an input capacitor in the inverter is charged by a DC-DC converter connected with the auxiliary battery as its power supply when the inverter starts. The system enables the auxiliary battery charging circuit to be small, light and low cost. The system can also charge the auxiliary battery for accessories even when the vehicle is stopping.

Abstract: A current transformer (4) detects the output currents of a voltage-type inverter (INV), and comparators (6) check whether the outputs from the current transformer exceed a predetermined limit value. The detected output currents are fed to a vector analyzer (8) to determine the location of the output current vector. A zone determining circuit (9) determines the location of the current vector in the zones. An output pattern generating circuit (10) responds to the output from the zone determining circuit (9) and provides a switching pattern corresponding to the voltage vector nearest to a vector having the direction opposite to that of the output current vector. A selector (2), being controlled by the comparator (6), selects a switching pattern from the output pattern generating circuit and provides it to the inverter (INV), when the comparator (6) detects that the magnitude of the current vector exceeds the predetermined limit value.

Abstract: A photoelectric conversion-type rotational position indicator for indicating the rotational position of a rotating body, including a light receiving member having one or more identically shaped light receiving portions made from a photoelectric converting material at predetermined spacings on the light receiving member to generate sinusoidal signals out of phase from each other, and a light shielding member operably connected to the rotating body such that the light shielding member rotates with the rotating body, the light shielding member having windows shaped with an inner curve and an outer curve such that the visible area of each light receiving portion through each of the windows varies in a sinusoidal form of one cycle as the light shielding member rotates, and means for obtaining the phased separated sinusoidal signals by connecting groups of light receiving portions in parallel or series.

Abstract: A non-contact, non-electromagnetic, compact, lightweight rotating body rotational-position detecting apparatus in which a disk or ring-shaped light source is spaced from a light receiving plate having thereon a region of photovoltaic material, by a shield plate which is coupled to the rotating body. The shield plate has a light-passing aperture therein so that the area of the photovoltaic material which is exposed to the light source varies with the angular position of the rotating body. The light source, photovoltaic regions, light shield and the shaft carrying the light shield and coupled to the rotating body are coaxial, the voltage produced across the load coupled to each of the photovoltaic regions being a function of the angle of rotation of the rotating body, thus indicating the angular position of the rotating body at any moment.