Abstract: A power conversion apparatus is for converting polyphase ac power directly to ac power. A conversion circuit includes a plurality of first switching devices 311, 313, 315 and a plurality of second switching devices 312, 314, 316 connected, respectively, with the phases R, S, T of the polyphase ac power, and configured to enable electrical switching operation in both directions. There are provided a plurality of condensers 821˜826 connected with the conversion circuit. At least one of the condensers is provided, for each of the first switching devices and the second switching devices, between two of the phases of the polyphase ac power. It is possible to reduce a wiring distance between the condenser and the switching devices.

Abstract: An electrical power converter for an incoming AC transformer connected to a multiphase power source and having multiple secondary windings. Each secondary winding is connected to multiple switching cells, each of which functions like a matrix converter. The secondary windings can be either single or multi-phase and more than one transformer can be provided such that the multiple secondary windings can be distributed among individual transformers. The output of at least two of the switching cells are connected in series. The switching cells can be either bi-directional or unidirectional and can also have a three-phase input. A combination of IGBTs and diodes can form the switching cells.

Abstract: Electrical power monitoring apparatus comprises a loop and a first conductor. A current sensor coupled to the first conductor provides a current signal that is representative of the current in the first conductor. A voltage sensor coupled at least to the first conductor provides a voltage signal that is representative of the voltage on the first conductor relative to that on a reference terminal. A multiplier coupled to the current sensor and voltage sensor has a power output which provides a power signal that is proportional to the instantaneous value of electrical power carried by the first conductor. A calibration circuit in the loop has an input coupled to the power output and has an adjustable output. A current regulator in the loop has an input coupled to the adjustable output to maintain the current in the loop between predetermined minimum and maximum loop current values.

Abstract: A method and apparatus for providing a source of alternating current electrical power to a plurality of loads in an office environment, including a plurality of non-linear loads which draw power for only a portion of the alternating current cycle, includes an input source of electrical power to a primary side of a power transforming device which provides an output at its secondary side which comprises at least two phases and a shared neutral. The plurality of loads are evenly distributed between each phase of the output power source and the shared neutral so as to reduce by current cancellation the current which would otherwise flow in the shared neutral conductor due to the presence of the non-linear loads. In one embodiment, each of six output phase is separated from the other by 120 electrical degrees, and the fourth, fifth and sixth phases are separated from the first, second and third phases, respectively, by 180 electrical degrees.

Abstract: Two-phase voltage signals for use with a resolver-to-digital converter (RDC) are produced as a periodic function of permeance developed across an air gap between a rotor and stator wherein the permeance varies as a periodic sinusoidal function which can be related to the electrical angle of the position of the rotor. The two-phase voltage signals are developed as a function of inductive reactance and follow the form ##EQU1## wherein the phase angle between V.sub.x and V.sub.y is exactly 90.degree. and the term [A+A.sub.n +B+B.sub.n ] is completely free of second harmonics.

Abstract: In apparatus for indirectly measuring the output DC current of a rectifier device on the input side of a polyphase rectifier transformer, a polyphase auxiliary current transformer is provided and the polyphase primary or secondary windings thereof are combined such that the area of the decreasing secondary current waveform is made equal to the area of the increasing secondary current waveform during commutation thereby releaving the secondary current from the adverse effect of the overlap angle.

Abstract: This phase converter utilizing a reference alternating voltage and producing a phase displaced voltage of same frequency having a common point with the reference voltage comprises a first summation and rectifying unit receiving at a first input the reference voltage and at a second input the phase displaced voltage a second summation and rectifying device receiving a first input the reference voltage and at a second input the phase-displaced voltage a second inverter being switched in at one of said inputs of said second summation and rectifying device both summation and rectifying devices having each an output connected to one input of a summation and filtration device receiving at another input a reference voltage a third inverter being switched in at the output of one of said summation and rectifying devices and said summation and filtration device having an output connected to a control terminal of a field effect transistor.