Abstract: According to at least one embodiment, an uninterruptible power supply (UPS) is provided. The UPS includes a first input configured to couple to a primary power source to receive primary power; a power bus coupled to a plurality of battery modules to receive back-up power; an output operatively coupled to the first input and the power bus to selectively provide, from at least one of the primary power source and the plurality of battery modules, uninterruptible power to a load; and a charge bus coupled to the plurality of battery modules to provide power to the plurality of battery modules. The UPS is configured to detect at least one battery module of the plurality of battery modules has reached a charging threshold and discontinue charging of the at least one battery module in response to detecting the at least one battery module has reached the charging threshold.

Abstract: A system applicable for use in an electric vehicle, for example, for controlling a separately-excited DC motor, permits field current control over all operating speed ranges of the motor. Below base speed a current limiting resistor is placed in series with the armature winding and the torque is directly proportional to field current. Above base speed, the resistor is shorted, and the speed is inversely proportional to field current. A feedback network is responsive to acceleration and deceleration input signals for controlling the magnitude of field current. A logic network provides automatic control, including switching battery interconnections, for changing the operating speed range of the motor by changing the level of voltage applied across the armature winding.

Abstract: A control system for a multi-phase synchronous machine having a shaft driven at variable speed or for developing a variable torque angle includes shaft angular position detectors that derive first and second output pulses respectively representing a shaft angular displacement corresponding with each pole of the machine and a predetermined shaft angular displacement within each pole. In response to a plurality of the second output pulses, a frequency locked loop derives a variable frequency pulse output. Individual pulses are selectively inserted and deleted from the variable frequency output to derive a variable phase pulse output representing machine torque angle. A triangle up/down counter responds to the variable phase output to derive a pulse output signal having a frequency that is a submultiple of the variable frequency output and a phase determined by the phase of the variable phase output.

Abstract: A method and apparatus for producing a plurality of pulse width modulated control signals, the combination of which are pulsed representations of the pattern of a reference waveform, comprises a sine wave generating network for producing the reference sine wave, a triangular waveform generating network for producing a triangular wave, a plurality of level shifting circuits for level shifting the triangular wave to produce a plurality of triangular waves each at a different level and having a different range of amplitudes, and a plurality of comparators each for comparing an individual one of the plurality of level shifted triangular waves with each half-cycle of the reference sine wave, for producing the plurality of control signals. The control signals may be decoded by decoding networks, the decoded control signals being applied for operating a waveform synthesizer or inverter stage to produce a multitiered steplike notched waveform equivalent of the reference waveform.

Abstract: A method and apparatus for producing control signals for operating an inverter circuit to convert a DC voltage into multitiered steplike notched N phase AC output signals (N=some positive integer number other than zero). A plurality of N reference sine waves are generated 90.degree. out of phase with one another for N=2, and for N greater than 2, successive ones of said N reference sine waves are generated 360.degree./N out of phase with each other. First through third triangular sampling or timing waveforms are generated and concurrently compared with the uppermost, central and lowermost portions, respectively, of each individual one of said N reference sine waves, for producing N sets of first, second and third pulse width modulated pulse trains, respectively. Decoding logic networks are receptive of these N sets of first through third pulse trains, for decoding these pulse trains into the necessary control signals for operating a particular inverter circuit.