Abstract: A projection system incorporating a prism with dual total internal reflection function, to increase the performance of DLP™ projection, by offering a solution to combine 2 light paths to contribute to the brightness on the screen and at the same time rejecting flat-state and off-state light from entering the projection lens thereby enhancing contrast. In one implementation those two light paths can be collecting light from 2 different light sources which are driven in a pulsed manner with a duty cycle of approximately 50% for each of the two light sources at increased power. In a second implementation with a color sequential single DMD™ projector, while one light path passes a primary color the second light path passes the complementary secondary color. A special color transformation algorithm is proposed to transform the image input signals to make optimal use of the capabilities offered by the second implementation, and create maximum brightness and color saturation of the image.

Abstract: A converter includes a converter circuit 1 having a plurality of bridge-connected semiconductor switching devices for converting AC power into DC power, a smoothing condenser connected in parallel to the DC side of the converter circuit and a current detector provided in a condenser circuit to control a condenser current flowing through the smoothing condenser to be a set value. The condenser current is controlled to be the set value (e.g. zero) to thereby reduce the capacity of the smoothing condenser and make the converter small.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, a charging circuit for controlled charging the storage capacitor and an output circuit for controlled discharge of the storage capacitor to provide single phase AC power to a third output terminal. The charging circuit controls input to the storage capacitor to provide a sinusoidal input current and to step up the voltage to the storage capacitor. The output circuit provides output power to the third output terminal of a predetermined phase and amplitude, relative to the other two output terminals, to result in balanced three phase AC power at the three output terminals.

Abstract: The present invention provides a control algorithm which instantaneously detects magnetic pole positions in the inside of a motor including polarities of the motor. A controller 1 applies a minute voltage change vhd to a voltage command on a dc axis which constitutes an estimation magnetic pole axis of the motor 3, detects electric currents Idc, Iqc of a motor 3 and discriminates the polarities of the magnetic pole axes by making use of the difference between a cycle in which ripple components of the electric currents Idc, Iqc become positive and a cycle in which the ripple components become negative or the difference between positive-side and negative-side current change rates. Further, the minute voltage change vhd with respect to the above-mentioned voltage command is generated on both of the dc axis and the qc axis rectangular thereto, and the magnetic pole positions of the motor are directly estimated based on the current ripple components on the respective axes.

Abstract: The present invention relates to a power factor compensation device for a motor driving inverter which can improve a power factor of a voltage and a current inputted to the inverter driving a motor. The present invention detects a zero crossing point of an utility alternating current power, and outputs a driving signal corresponding to a plurality of sine wave form voltage values stored in a memory according to a detection result, when the zero crossing point of the utility alternating current power is detected in a state where the plurality of sine wave form voltage values corresponding to a voltage of the utility alternating current power and frequencies are stored in the memory. A switching transistor is switched according to the driving signal, and the voltage applied to the inverter is switched according to the switching operation, thereby improving the power factor.