Toshiba International Corporation

David Westmoreland

Yoichi Morishima

Tatsuaki Ambo

Jigarkumar Lakshmanbhai Patel

Stephen A Hallacy

The presently disclosed embodiments are directed to an improved communication system that may have a plurality of control board modules and a display. The object of the disclosure is to transfer critical communication from the critical communication channel to the non-critical communication channel in the event of communication failure in the critical communication channel. Another object of the disclosure is to share data transfer between communication channels in order to manage bandwidth and system reliability.

Redundant communication system to increase operational reliability

In accordance with presently disclosed embodiments, a 5-switch power conversion circuit that improves the power conversion efficiency (PCE) of a DC-DC converter with a double chopper topology is provided. The power conversion circuit adds minimal complexity through an additional switch, while preserving the benefits of a 3-level boost converter topology. The disclosed power conversion circuit uses four switches that are arranged in a 3-level boost converter arrangement, and a fifth switch that is connected in parallel with two of the other switches. The fifth switch helps to reduce the conduction power losses through the DC-DC converter by providing a one-switch ON-state conduction path instead of a two-switch path during part of the DC-DC power conversion cycle.

Multi-switch power converter

An inductor-capacitor (LC) filter designed to comply with EMC (Electromagnetic Compatibility) standards comprises capacitors; switches for coupling capacitors; differential-mode inductors for coupling capacitors and switches; and common-mode inductors or a combination of differential-mode inductors and common-mode inductors, where an input signal changes the inductance of differential-mode inductors in the LC filter to modify a frequency response of the LC filter. In the LC filter, differential-mode inductors further comprise identical multiple-winding inductors, and the input signal, which biases the plurality of differential-mode inductors, includes a DC signal or a combination of DC and AC signals. A corner-frequency of the LC filter is adjusted and approximated as: fc=1/(2&#xd7;pi&#xd7;sqrt(L&#xd7;C)), where fc is the corner-frequency, L is a composite value of inductance, and C is a composite value of capacitance.

Tunable LC filter

According to some preferred embodiments, power converter includes a comparator circuit with feedback from current-fed PI or PID control to select one of two regeneration times of at least one active clamp: i) wherein at low loads a regeneration circuit is turned ON for substantially an entire current-transfer cycle such as to avoid output of current-fed converter continuing to rise; and ii) wherein at high loads the regeneration period is reduced to between about &#xbc; to &#xbd; of a resonance-frequency cycle so that a resonance between the regeneration capacitance and the transformer's leakage inductance avoids excessive ringing currents and/or lost efficiency.

Active clamp resonance control

An uninterruptable power supply (UPS) designed to switch power inputs between an alternating current mode and a battery mode by adjusting the amplitude and/or frequency windows of the input voltage so that the uninterruptible power supply accepts the unstable voltage and/or frequency. This prevents the uninterruptible power supply to switch back to the battery mode during a transfer time between the battery mode and the AC mode. The uninterruptable power supply includes a control circuit. The control circuit modifies the monitored value and/or actual amplitude and/or the frequency window when unstable amplitude and/or an unstable frequency are detected at the input terminal of the input voltage.

Adjustable UPS protection

An uninterruptable power supply (UPS) designed to switch power inputs between an alternating current mode and a battery mode having a sensor to monitor a load current, and a central processing unit (CPU) to boost a bus voltage of the uninterruptable power supply by increasing a calculated reference voltage to a target reference voltage by a slope. The calculated reference voltage is calculated by the CPU based on a voltage drop value in main capacitors that occurs during a transfer time between the battery mode and the AC mode. The target reference voltage is the voltage across an equivalent circuit of the main capacitors before the voltage drop. The slope is based on a ratio of a voltage drop value across an equivalent circuit of main capacitors and a charging up time to reach the target reference voltage.

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Houston, TX, United States of America

David Westmoreland