Abstract: An apparatus for carrying out a current control and method therefor are disclosed in which the current control is such that no 0 vector defect is present by switching from a three-arm modulation method to a two-arm modulation method in the vicinity to a voltage saturation in a PWM inverter using the three-arm modulation method. The structure of the current control apparatus is such that in the PWM inverter using the three-arm modulation method having a time point data preparing section which prepares a time point data for the three-arm modulation mode from voltage vector times T .lambda., T.mu.

Abstract: An apparatus and method for measuring at least one desired motor constant applicable to an equivalent circuit of the induction motor according to the present invention utilizes a vector controlled speed variable apparatus for the induction motor. After the input and output parameters of the induction motor are measured, the apparatus calculates and measures the desired motor constant using a corresponding equation. For example, the secondary circuit time constant is calculated using the following equation. That is to say,.tau..sub.2 .apprxeq..tau..sub.2q * and V.sub.1q *(t)=(V.sub.1q *).sub.+0.exp(-(1/.tau.2q*).t)wherein (V .sub.1q *).sub.+ denotes a control q-axis primary voltage component immediately after torqu and excitation current instructions have been changed to zero and output from a current control system (ACR), V.sub.1q *(t) denotes a time function of V.sub.1q * at each sampling period after the current instructions have been changed in the stepwise manner to zero.

Abstract: A current detection method for current detection of an output of a PWM inverter utilitizes current sampling at the timings of two zero vectors of the PWM inverter and selecting the sample value least influenced by noise as the detected current sample value and, when a time difference between the two vectors is large, an average value of the two sample values is selected.

Abstract: A digital control system such as a digital temperature compensated crystal oscillator (DTCXO) system is arranged to offer superior oscillating performance with reduced size and cost. For example, to reduce the memory capacity, a memory 31 receives upper 6 bits of temperature data, and a decoder 32 calculates temperature compensation data from lower 4 bits and output data from the memory (FIGS. 1-11). For a one-chip configuration and low power consumption, a MOS type Colpitts oscillator (FIG. 16) is provided with a circuit for adjusting the source resistance of the MOS. For size reduction and fine frequency adjustment, a DTCXO is provided with sections such as an adder 341, an up-down counter 342 and an auxiliary frequency control section (AFC) 332 (FIGS. 20, 21, 24 and 25). An adding section 415 is provided between a D/A converting section 414 and a capacitance varying section 416 to obtain superior linearity with respect to a control voltage and quality of offset.

Abstract: A control system for a chassis dynamometer for bench testing vehicular performance, comprises at least one roller rotatably coupled with a vehicular wheel the roller to be driven by driving torque transmitted from the vehicular wheel therefrom, at least one dynamometer coupled with the roller to be driven by driving torque transmitted through the roller, a first monitor for monitoring preselected control parameters for providing first chassis dynamometer control data, a second monitor for monitoring rotary components in a system associated with the dynamometer including the dynamometer per se, for providing second chassis dynamometer control data, and a control signal generator for receiving the first and second chassis dynamometer control parameters for deriving a dynamometer control signal generating a control signal to the dynamometer for providing a rolling resistance to the vehicular wheel at the roller simulating a predetermined vehicular driving condition.

Abstract: An electromagnetic compatibility simulating apparatus for an automobile including an electromagnetically shielded cell having a wall dividing the interior of the cell into a first chamber for the automobile and a second chamber. Road simulator units are mounted within the second chamber. Dynamometers are mounted within the second chamber in driving relation with the road simulator units. The wall has windows for allowing driving contact of the road simulator units with the road wheels, and blower openings for allowing air feed from blowers. Electromagnetic wave absorbers and reflecting wall portions are disposed on the windows. Expanded metals cover the blower openings or metal pipes are disposed between the blower and the blower openings. The wall has inspection windows with shutters on which electromagnetic shielding net is disposed. A controller is disposed outside the first and second chambers. Conductors connect the controller with the dynamometers and blowers.

Abstract: A method for calculating a speed estimated value in a speed control system, comprises the steps of: (a) storing the number of speed detection pulses obtained at each interval of a speed control process and time that the speed detection pulse was obtained; (b) calculating a detection speed from the number of latest speed detection pulses and its detection time, and the number of the previously stored speed detection pulses and its detection time; (c) executing an averaging process of motor model output corresponding to time that the detection speed was obtained; (d) obtaining a difference between an output obtained at said step (c) and the detection speed; (e) executing a calculation of a load torque estimation by multiplying the difference of the step (d) by an observer gain; (f) executing an estimation of a motor speed for next processing from the difference of the step (d) and a difference between the detection speed and the motor model output; (g) calculating an output of a speed amplifier by constituting

Abstract: Improved speaker independent speech recognition system and method are disclosed in which an utterance by an unspecified person into an electrical signal is input through a device such as a telephone, the electrical signal from the input telephone converting the electrical signal into a time series of characteristic multidimensional vectors, the time series of characteristic multidimensional vectors are received, each of the vectors being converted into a plurality of candidates so that the plurality of phonemes constitutes a plurality of strings of phonemes in time series as a plurality of candidates, the plurality of candidates of phonemes are compared simultaneously (one at a time) with a reference pattern of a reference string of phonemes for each word previously stored in a dictionary to determine which string of phonemes derived from the phoneme recognition means has a highest similarity to one of the reference strings of the phonemes for the respective words stored in the dictionary using a predetermine

Abstract: A speed estimation observer for a motor control system outputs a motor speed estimate in a motor speed control system upon receiving a torque command and an averaged motor speed value. The speed estimation observer includes a time lag correction value calculating block for implementing a correction of a model output speed estimate. Therefore, the accuracy and stability of the speed estimation are improved, and the control system keeps the stability in a speed range of low to high speed and ensures the disturbance suppressing effect in a high speed range.

Abstract: A pulse generator is composed of switch means to switch supply of a first current through a circuit, a first condenser connected to the switch means in series and primary charged by the first current, voltage raising means having a primary winding serially connected to the first condenser and a secondary winding to obtain voltage output by the first current, magnetic switch means of current flow switchable having a primary winding serially connected to the secondary winding of the voltage raising means and a secondary winding, a second condenser connected to the secondary winding of the magnetic switch means and charged by the output therefrom, and discharging means connected to the second condenser to generate pulse discharge when charged voltage of the second condenser is applied thereto by switching the magnetic switch means.

Abstract: A process for forming an electrode assembled into a vacuum interrupter is composed of the steps of blending silver(Ag) powder and chromium(Cr) powder in a content ratio such that Ag powder forms a matrix and Cr powder being dispersed therein, the blending ratio is prefer to be determined to contain 50 to 95 wt. % of Ag powder and 5 to 50 wt. % of Cr powder, compacting the blended powder to a compacted body, sintering the body at temperatures around melting point of Ag, and regulating density of the sintered article at least 90%. Particle size of Cr to be blended may be determined less than 150 .mu.m, more preferably, less than 60 .mu.m. Sintering temperature may be determined between 800.degree. to 950.degree. C.

Abstract: A method for forming an electrical contact material comprises the steps of melting a mixture of Cu and Cr into a molten alloy, atomizing the molten alloy into fine particles to obtain alloyed particles. Cr particles in the alloyed powder disintegrate to less than 5 .mu.m in mean particle diameter. The alloyed powder is sintered thereafter and a mean particle diameter of chromium in the sintered article is fined in a range of 2 to 20 .mu.m. An electrical contact material is composed of a copper matrix and chromium particles having a mean particle diameter of 2 to 20 .mu.m. The chromium particles are homogeneously dispersed in the copper matrix.

Abstract: A vector control system of an induction motor using the slip frequency control method comprises means for minimizing an error with regard to compensation for variation of a secondary resistance.

Abstract: A system for testing a power train assembly such as a transaxle of a vehicle has first and second gear units each having separate input members for receiving input torque from the power train assembly to be tested, a mounting member for supporting the power train assembly between the first and second gear units, a drive motor for supplying input torque to the power train assembly, and a dynamometer connected with the second gear unit. The drive motor is connected with the input member of the power train assembly by a driving shaft passing through the first gear unit. Preferably, the first and second gear units are connected by at least one interconnecting shaft extending under the power train assembly. With this arrangement, the test system is smaller in required space, smaller in inertia, capable of high speed testing, and readily applicable to different types of power train assemblies.

Abstract: A method and system for estimating an inertia of 2-mass system constituted by a motor and a load connected through a torsionable shaft during operation. The estimating method is implemented as follows: (a) obtaining a deviation between a motor speed preset value and a motor speed in a deviation section; (b) inputting the deviation from the deviation section into an adding section through a speed control amplifier; (c) obtaining a motor generating torque by inputting the output from the speed control amplifier and the load torque estimate into an adding section; (e) inputting the motor generating torque into a model of the 2-mass system; and (f) obtaining an inertia error by inputting the load torque estimate into the inertia error estimating section. With this method, it becomes possible to estimate the inertia of the 2-mass system even if the load inertia is varied during operation.

Abstract: An apparatus for synthesizing speech from text includes a language processing section which determines an accent environment of each mora of the text. In a basic accent pattern table, a basic accent pattern is classified according to the accent environment of the mora. The basic accent pattern includes a pitch data which is edited from real voice data according to the accent environment. A basic accent pattern processing section selects the basic accent pattern of each more from the basic accent pattern table according to the accent environment and processes the basic accent pattern in pitch according to the accent environment. A correcting section receives the corrected pitch data in the basic accent patter processing section and corrects the corrected pitch data according to the number of mora in each phrase and the position of the mora in phrase so as to correct the data into the corrected accent component.