Powerware Corporation

Joseph R Wade

Donald K Zahrte, Sr

Peter William Jungwirth

Derek Laufenberg

Craig Edevold

Cary Frank Winch

Glenn A Koosmann

Presented is a control system and method for minimizing the adverse affects resulting from conventional hysteretic current control of power inverters, and an uninterruptible power supply using same. The system of the present invention uses control circuitry for monitoring and classifying the PWM switching events commanded by conventional hysteretic current control and adjusting the dead time delay injected based on these PWM events. Preferably, the control circuitry uses a minimum delay dead time component to preclude the possibility of a shoot through condition from occurring, and also includes a frequency control component of the total dead time delay. In one embodiment this frequency control component may vary in proportion to the switching frequency commanded by the hysteretic current control loop. In an alternate embodiment, the PWM switching events are classified into differing modes of operation, during which a particular fixed frequency control dead time delay is selected. The control of the present invention may also use a maximum difference current control limit for the dead time delay to preclude excessive output current swings beyond the typical hysteretic current control limits.

Hysteretic current control method and an uninterruptible power supply using same

A charging control circuit for severe battery conditions and an uninterruptible power supply (UPS) system including same are presented. The charging control circuit utilizes both hardware and microprocessor control to allow the UPS to start with depleted or no batteries installed. Initially, the hardware control loops regulate DC bus voltage generation to charge the batteries to a safe level to allow the UPS housekeeping circuitry to wake up and assume control of the UPS operation. Once the microprocessor has awoken, it assumes control of the DC bus and charging of the batteries. If no batteries are installed, the hardware control loop utilizes a fast responding voltage mode control to regulate the DC bus, while a microprocessor-based current mode control is used when batteries are installed. Hardware over voltage control and microprocessor shut off control is also provided.

Battery charger control circuit and an uninterruptible power supply utilizing same

Presented is a single-stage power converter topology allowing for power factor correction during operation. The topology utilizes an integration of &Cacute;uk converter and single-ended primary inductance converter (SEPIC) topologies to provide AC-to-AC, AC-to-DC, DC-to-AC, and AC/DC-to-AC operation. Shared use of the &Cacute;uk converter's output inductor by the SEPIC-type circuit elements provides continuous output current, typically unknown to a SEPIC converter. Application of the single-stage power converter topologies may be had in a line conditioner circuit, a battery charger circuit, and as an uninterruptible power supply (UPS).

Single-stage power converter and an uninterruptible power supply using same

Presented is a modular uninterruptible power supply system utilizing common power modules, and providing redundant coordinated control thereof. The system and method of the instant invention provides identical control logic within each of the individual power modules, thus dispensing with the requirement for a separate control module to control and coordinate the operating modes and parameters of the UPS system. A system is presented whereby a virtual master is established through an arbitration scheme at initialization of the UPS system. The master then assigns a virtual vice master to provide the redundant back up control should the virtual master no longer be able to perform its functions. Nearly simultaneous control of operational mode and state change functions is accomplished through a coordinated communications system including a high-speed communications bus and digital control logic lines. Also provided is a mechanism for removal of the virtual master from its duties upon the detection of a problem that is not detected by the virtual master itself.

Method and apparatus for coordinating uninterruptible power supply modules to provide scalable, redundant power

A modular uninterruptible power supply is presented having multiple power modules installed therein. Each of the individual power modules contains an internal bypass circuit sized for its particular power module. Preferably internal bypass circuitry is sized to carry two per unit load. The system and method of the invention also includes internal control circuitry for each of the modular power modules that control transitions between the inverter and bypass modes of operation. This transition control is coordinated with the other controllers for the other modular power modules installed in the uninterruptible power supply. Both the high speed communication bus and a high level interrupt line are utilized to minimize the transfer break time between different modes of operation while ensuring that the inverter is never paralleled with the utility line voltage. To further minimize this transfer time, a solid state switching circuit is utilized to provide the initialization between operational modes. To maximize the efficiency during the bypass mode of operation, and electromechanical relay is utilized in coordinated operation with the solid state switching device to provide long-term power requirements during the bypass mode.

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Mindoro, WI, United States of America

Joseph R Wade